Post on 31-Dec-2015
6
Chapter 1
Introduction
Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display
7
1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS
The term The term telecommunicationtelecommunication means means communication at a distance The word communication at a distance The word datadata refers refers to information presented in whatever form is to information presented in whatever form is agreed upon by the parties creating and using the agreed upon by the parties creating and using the data data Data communicationsData communications are the exchange of are the exchange of data between two devices via some form of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable
ComponentsData RepresentationData Flow
Topics discussed in this sectionTopics discussed in this section
8
Figure 11 Five components of data communication
9
Data Representation
bull TEXT ndash unicode (32 bits to represent character)- ASCII
bull NUMBERS bull IMAGES-composed of a matrix of pixelbull AUDIO- recording or broadcasting of sound or
musicbull VIDEO- recording or broadcasting of a bull picture or movie
10
Figure 12 Data flow (simplex half-duplex and full-duplex)
11
1-2 NETWORKS1-2 NETWORKS
A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) connected by communication ) connected by communication linkslinks A node A node can be a computer printer or any other device can be a computer printer or any other device capable of sending andor receiving data generated capable of sending andor receiving data generated by other nodes on the networkby other nodes on the network
Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork
Topics discussed in this sectionTopics discussed in this section
12
NETWORKS
Set of nodes connected via physical links ndash 1) Distributing Processing ndash 2) Sharing Data and centralization ndash 3) Security and robustness
13
Network Criteria
bull
1) Performance Transmission and response times - throughput and delay 2) Reliability How often the networks fail 3) Security Privacy and integrity of communication Data recovery from breaches and data loss
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
7
1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS
The term The term telecommunicationtelecommunication means means communication at a distance The word communication at a distance The word datadata refers refers to information presented in whatever form is to information presented in whatever form is agreed upon by the parties creating and using the agreed upon by the parties creating and using the data data Data communicationsData communications are the exchange of are the exchange of data between two devices via some form of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable
ComponentsData RepresentationData Flow
Topics discussed in this sectionTopics discussed in this section
8
Figure 11 Five components of data communication
9
Data Representation
bull TEXT ndash unicode (32 bits to represent character)- ASCII
bull NUMBERS bull IMAGES-composed of a matrix of pixelbull AUDIO- recording or broadcasting of sound or
musicbull VIDEO- recording or broadcasting of a bull picture or movie
10
Figure 12 Data flow (simplex half-duplex and full-duplex)
11
1-2 NETWORKS1-2 NETWORKS
A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) connected by communication ) connected by communication linkslinks A node A node can be a computer printer or any other device can be a computer printer or any other device capable of sending andor receiving data generated capable of sending andor receiving data generated by other nodes on the networkby other nodes on the network
Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork
Topics discussed in this sectionTopics discussed in this section
12
NETWORKS
Set of nodes connected via physical links ndash 1) Distributing Processing ndash 2) Sharing Data and centralization ndash 3) Security and robustness
13
Network Criteria
bull
1) Performance Transmission and response times - throughput and delay 2) Reliability How often the networks fail 3) Security Privacy and integrity of communication Data recovery from breaches and data loss
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
8
Figure 11 Five components of data communication
9
Data Representation
bull TEXT ndash unicode (32 bits to represent character)- ASCII
bull NUMBERS bull IMAGES-composed of a matrix of pixelbull AUDIO- recording or broadcasting of sound or
musicbull VIDEO- recording or broadcasting of a bull picture or movie
10
Figure 12 Data flow (simplex half-duplex and full-duplex)
11
1-2 NETWORKS1-2 NETWORKS
A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) connected by communication ) connected by communication linkslinks A node A node can be a computer printer or any other device can be a computer printer or any other device capable of sending andor receiving data generated capable of sending andor receiving data generated by other nodes on the networkby other nodes on the network
Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork
Topics discussed in this sectionTopics discussed in this section
12
NETWORKS
Set of nodes connected via physical links ndash 1) Distributing Processing ndash 2) Sharing Data and centralization ndash 3) Security and robustness
13
Network Criteria
bull
1) Performance Transmission and response times - throughput and delay 2) Reliability How often the networks fail 3) Security Privacy and integrity of communication Data recovery from breaches and data loss
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
9
Data Representation
bull TEXT ndash unicode (32 bits to represent character)- ASCII
bull NUMBERS bull IMAGES-composed of a matrix of pixelbull AUDIO- recording or broadcasting of sound or
musicbull VIDEO- recording or broadcasting of a bull picture or movie
10
Figure 12 Data flow (simplex half-duplex and full-duplex)
11
1-2 NETWORKS1-2 NETWORKS
A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) connected by communication ) connected by communication linkslinks A node A node can be a computer printer or any other device can be a computer printer or any other device capable of sending andor receiving data generated capable of sending andor receiving data generated by other nodes on the networkby other nodes on the network
Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork
Topics discussed in this sectionTopics discussed in this section
12
NETWORKS
Set of nodes connected via physical links ndash 1) Distributing Processing ndash 2) Sharing Data and centralization ndash 3) Security and robustness
13
Network Criteria
bull
1) Performance Transmission and response times - throughput and delay 2) Reliability How often the networks fail 3) Security Privacy and integrity of communication Data recovery from breaches and data loss
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
10
Figure 12 Data flow (simplex half-duplex and full-duplex)
11
1-2 NETWORKS1-2 NETWORKS
A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) connected by communication ) connected by communication linkslinks A node A node can be a computer printer or any other device can be a computer printer or any other device capable of sending andor receiving data generated capable of sending andor receiving data generated by other nodes on the networkby other nodes on the network
Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork
Topics discussed in this sectionTopics discussed in this section
12
NETWORKS
Set of nodes connected via physical links ndash 1) Distributing Processing ndash 2) Sharing Data and centralization ndash 3) Security and robustness
13
Network Criteria
bull
1) Performance Transmission and response times - throughput and delay 2) Reliability How often the networks fail 3) Security Privacy and integrity of communication Data recovery from breaches and data loss
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
11
1-2 NETWORKS1-2 NETWORKS
A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) connected by communication ) connected by communication linkslinks A node A node can be a computer printer or any other device can be a computer printer or any other device capable of sending andor receiving data generated capable of sending andor receiving data generated by other nodes on the networkby other nodes on the network
Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork
Topics discussed in this sectionTopics discussed in this section
12
NETWORKS
Set of nodes connected via physical links ndash 1) Distributing Processing ndash 2) Sharing Data and centralization ndash 3) Security and robustness
13
Network Criteria
bull
1) Performance Transmission and response times - throughput and delay 2) Reliability How often the networks fail 3) Security Privacy and integrity of communication Data recovery from breaches and data loss
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
12
NETWORKS
Set of nodes connected via physical links ndash 1) Distributing Processing ndash 2) Sharing Data and centralization ndash 3) Security and robustness
13
Network Criteria
bull
1) Performance Transmission and response times - throughput and delay 2) Reliability How often the networks fail 3) Security Privacy and integrity of communication Data recovery from breaches and data loss
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
13
Network Criteria
bull
1) Performance Transmission and response times - throughput and delay 2) Reliability How often the networks fail 3) Security Privacy and integrity of communication Data recovery from breaches and data loss
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
14
Physical Structures
bull Types of connections bull 1) Point to Point (P to P) Dedicated link to be
utilized only by end devices bull 2) Multipoint (Multidrop) Many end devices
share the link capacity
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
15
Figure 13 Types of connections point-to-point and multipoint
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
16
Physical Topology
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
17
Figure 14 Categories of topology
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
18
Physical Topology
bull A) Mesh
bull Each device has dedicated point-to-point link to other devices Fully connected mesh will have n( n-1) 2 FD links ndash Where n = number of nodes
bull Advantages Fast communication Robust and Privacy (Security)
bull Disadvantages Cabling Space and cost
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
19
Figure 15 A fully connected mesh topology (five devices)
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
20
Physical Topology (cont)
bull B) Star
bull Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger)
bull Advantages Less cabling and HW ports two hops only
bull Disadvantage Not robust
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
21
Figure 16 A star topology connecting four stations
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
22
Figure 17 A bus topology connecting three stations
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
23
ndash C) Bus
bull Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into the bus
Advantage Less Cabling bull Disadvantages Topology dependent limit
number of nodes on the bus due to signal power loss with distance not so robust
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
24
Figure 18 A ring topology connecting six stations
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
25
bull C) Ring Each device connects Point to Point with only two other devices in a left and right neighbors arrangement via a repeater
bull Advantages easy installation better fault isolation and robustness
bull Disadvantages N2 hops communication
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
26
Figure 19 A hybrid topology a star backbone with three bus networks
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
27
bull D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo bull Pros Better robustness still low cost Delay is
1 hop (until the star is not with a ring cut max 2 bull Star of busses
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
28
Categories of Networks
bull Local Area Networks (LAN) Few Kilometers Connects devices (PCs printers servers) within the same room building company and campus
bull Topologies most used are bus ring and star
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
29
Figure 110 An isolated LAN connecting 12 computers to a hub in a closet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
30
Categories of Networks(cont)
bull Wide Area Networks (WAN)bull span a large geographical area about 100rsquos ndash
1000rsquos of Km bull 1) Switched End users connected via a cloud
of switches (subnet) bull 2) Point-to Point Line leased from telephone
company TV connecting users
to the ISP for Internet access
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
31
bull alternative technologies used includendash circuit switchingndash packet switchingndash frame relayndash Asynchronous Transfer Mode (ATM)
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
32
Circuit Switching
bull uses a dedicated communications path established for duration of conversation
bull comprising a sequence of physical linksbull with a dedicated logical channelbull eg telephone network
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
33
Packet Switching
bull data sent out of sequencebull small chunks (packets) of data at a timebull packets passed from node to node between
source and destinationbull used for terminal to computer and computer to
computer communications
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
34
Frame Relay
bull packet switching systems have large overheads to compensate for errors
bull modern systems are more reliablebull errors can be caught in end systembull Frame Relay provides higher speedsbull with most error control overhead removed
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
35
Asynchronous Transfer Mode(ATM)
bull evolution of frame relaybull fixed packet (called cell) lengthbull with little overhead for error controlbull anything from 10Mbps to Gbpsbull constant data rate using packet switching
technique with multiple virtual circuits
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
36
Figure 111 WANs a switched WAN and a point-to-point WAN
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
37
Figure 112 A heterogeneous network made of four WANs and two LANs
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
38
Categories of Networks(cont)
bull Metropolitan Area Networksbull MAN towncity bull High-speed backbone linking multiple LANrsquos
DSL TV cables
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
39
1-3 THE INTERNET1-3 THE INTERNET
The The InternetInternet has revolutionized many aspects of our has revolutionized many aspects of our daily lives It has affected the way we do business daily lives It has affected the way we do business as well as the way we spend our leisure time The as well as the way we spend our leisure time The Internet is a communication system that has Internet is a communication system that has brought a wealth of information to our fingertips brought a wealth of information to our fingertips and organized it for our use and organized it for our use
A Brief History The Internet Today (ISPs)
Topics discussed in this sectionTopics discussed in this section
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
40
The Internet
bull Internet evolved from ARPANETndash first operational packet networkndash applied to tactical radio amp satellite nets alsondash had a need for interoperabilityndash lead to standardized TCPIP protocols
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
41
The Internet
bull Huge number of interconnected Networks (100000rsquos) private organized egrsquo government schools research facilities in many countries
bull Collection of LANrsquoS MANrsquoS and WANrsquos ndash 1048708 The internet protocol stack is the TCPIP ndash 1048708 End users use the internet via Internet Service providers
(ISPs) which are of the following hierarchies
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
42
Figure 113 Hierarchical organization of the Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
43
Internet Elements
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
44
Internet Architecture
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
45
Example Configuration
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
46
1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS
In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol First we define protocol which is synonymous with rule Then we discuss which is synonymous with rule Then we discuss standards which are agreed-upon rulesstandards which are agreed-upon rules
ProtocolsStandardsStandards OrganizationsInternet Standards
Topics discussed in this sectionTopics discussed in this section
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
47
What is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamplesInternet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
48
bull Elements bull 1) Syntax PDU format
ndash 2) Semantics The meaning of each PDUrsquos field ndash 3) Timing Synchronization of communication when
PDU is to be transferred and its data rate
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
49
What is a standard
ndash bull A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity
ndash 1) ldquoDefactordquo not approved but widely used (TCPIP)
ndash 2) ldquoDejurerdquo approved by recognized body (IEEE 802X)
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet
50
Summary
bull introduced data communications needsbull communications modelbull defined data communicationsbull overview of networksbull introduce Internet