Data Communication & Networking IRISET TA-2122.252.230.113/content/ppt/tele/TA_2hl.pdf · Message:...

TA-2 Data Communication & Networking

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Basics of Data Communications

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Introduction to Datacom Communication means sharing of information

either it can be local (or) remote.

Data refers to facts. Concepts & instructions presented in what ever form is agreed upon by the parties creating and using the data

Data communication is the exchange of data (bits) between two devices via some form of transmission medium

In the context of computer information systems, data is presented by binary information units (or) bits.

J.Vijay Kumar, INW-2, Network Lab

Datacom Basics 3

To occur data communication it requires certain Hardware and Software

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Data communication system is made up of five components. They are

Message

Sender

Medium

Receiver

Protocol J.Vijay Kumar, INW-2, Network Lab

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Datacom Components

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Message: The information to be communicated, consists of text, numbers, pictures, sound & video.

Sender: Device that sends the message (data). It can be a computer, server, video camera etc.

Receiver: Device that receives the message (data). It can be a computer, server, television.

Medium: Physical path by which messages travels from sender to receiver. It may be twisted pair, co-axial cable , OFC, radio waves etc.


Datacom Basics 5

Datacom Components

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Protocols : Set of rules that governs data communication, represents an agreement between communicating devices. without protocol two devices may not communicate at all. Protocol defines what is communicated, how it is communicated and when it is communicated.

The key elements of protocols are

Syntax: Structure (or) format of the data divided into section of bits

Semantics: Refers to the meaning of each section of bits

Timing: The speed of sending & receiving systems should match the speed


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Datacom Components

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The Effectiveness of the data communication depends upon three (3) fundamental characteristics. They are

Delivery

Accuracy

Timeliness

J.Vijay Kumar, INW-2, Network Lab Datacom Basics 7

Effectiveness of Datacom

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Delivery The system must deliver data to the correct

destination

Accuracy The system must deliver data accurately, altered and

un-correct data are unusable

Timeliness The system must deliver data in a timely manner.

Data delivered late are useless J.Vijay Kumar, INW-2, Network Lab

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Effectiveness of Datacom

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Information or Data can be in the form of text, voice, picture or image, audio & video.

This Information can be in analog (or) digital form.

Analog Information is continuous.

In nature every information is in analog form.


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Information (or) Data

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It can have any instantaneous value in a range & it is called as periodic signal (periodic signal consists of a continuously repeated pattern)

Digital information is in discrete form.

It can have only a limited number of values & it is called as a-periodic Signal, a-periodic signal has no repetitive pattern

To transmit this information it must be converted into electromagnetic signals J.Vijay Kumar, INW-2,

Network Lab Datacom Basics 10

Information (or) Data

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Bandwidth: In context of Analog signal the Bandwidth is the range of frequencies that a medium can pass without loosing one-half of the power contained in that Signal.

e.g. for voice signal the Bandwidth is Highest - Lowest Frequency = 4000 – 0 Hz = 4000 Hz


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Bandwidth

In context of Digital signal the Bandwidth is the maximum bit rate that a medium can pass and is called as

BPS (bits per second)

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A digital signal can be decomposed into an infinite number of simple sine waves called harmonics each with different amplitude, frequency & phase.

Although the frequency spectrum of a digital signal contains an infinite no. of frequencies with different amplitudes. We Send only those components whose amplitudes are significant

Bit rate has a relation ship to significant BW, when bit rate increases significant BW increases.

e.g. 1000 bps = significant BW of 200HZ 2000bps = Significant BW of 400 HZ


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Bandwidth

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Hence medium’s BW capacity puts a limit on the bit rate

The maximum bit rate a transmission medium can transfer is called channel capacity of the medium

The capacity of a channel depends on the type of encoding technique and the signal- to- noise ratio of the system

A normal telephone line with a BW of 3000HZ is capable of transferring up to 20000bps

As significant BW increases with bit rate, we need a medium with wider significant BW to transfer signal


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Bandwidth

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Bit rate (BPS) is no. of bits transmitted in one second.

Baud rate refers to the symbol rate, how many symbol changes are transmitted per second.

Symbols can contain one or more bits, bit has only two states but symbols can have more than 2 states

Baud rate is less than (or) equal to Bit rate .


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BPS = Baud per second x Number of Bits per Baud

Bit rate & Baud rate

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. A figure of 2400 bits per second means 2400 zeros or ones can be

transmitted in one second, hence the abbreviation 'bps'.

Baud rate by definition means the number of times a signal in a

communications channel changes state.

For example, a 2400 baud rate means that the channel can change states

up to 2400 times per second.

Whether you can transmit 2400 zeros or ones in one second (bit rate), or

change the state of a digital signal up to 2400 times per second (baud rate),

it the same thing.

So we can conclude that in the above example, the bit rate is the same as

the baud rate. Hence, 1 bit rate = 1 baud rate for this example.

There are cases though where a channel can send 4 bits per baud,

meaning that for every 4 bits, we have one change, and in this case, the

baud rate is 1/4th of the bit rate.

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There are four(4) types of encoding techniques used Digital – to – Digital Digital – to – Analog Analog – to – Digital Analog – to – Analog

Before sending the data from one place to another, it should be encoded into signal.

Digital – to – Digital: Computer to Printer

Polar Bi-polar

RZ NRZ

Bi-Phase

AMI B8ZS HDB3

Uni-polar

(absolute)


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Encoding

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Digital - to – Analog: Used in MODEMs

ASK FSK PSK

QAM

Analog – to – Analog: Radio is familiar utility Amplitude Modulation Frequency Modulation Phase Modulation

Analog – to – Digital: recording voice onto CD (CODEC) PAM PCM


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Encoding

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QAM

PSK is limited by the ability of the equipment to distinguish small differences in phase.

This factor limits its potential bit rate.

It is a combination of ASK & PSK

8 QAM uses 2 amplitude & 4 phase changes

16 QAM uses 3 amplitude & 12 phase changes (or ) 4 amplitude & 8 phase changes.


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011

010

000 001

100 101

110

111

8 QAM


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Transmission of Digital Data

Parallel Transmission Serial Transmission

Synchronous Asynchronous

1. In parallel transmission multiple bits are sent with each clock pulse 2. parallel transmission is high speed, costly, suitable for short distance 3. In serial one(1) bit is send with each clock pulse.


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Asynchronous Serial Transmission

Extra bit called start bit is added at the beginning of each byte and also one or more stop bits are added at the end of the byte

In addition the transmission of each byte may then be followed by a gap of varying duration, this may be represented by additional stop bits

Asynchronous is at Byte level

Asynchronous is cheap, slow speed between a terminal and computer.


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Synchronous Serial Transmission

In synchronous transmission bits are send one after another without start / stop bits (or) gaps.

It is the responsibility of the receiver to group the bits

Byte synchronization is accomplished in data link layer

Synchronous transmission is high speed & software controlled


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A network is a set of devices (or) nodes connected by media links. A node can be a Computer, Printer (or) any other device capable of sending / receiving the data generated by other nodes on the network.

Network Criteria: For effective and efficient network it should meet the following.

Performance

Reliability

Security J.Vijay Kumar, INW-2, Network Lab

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Network

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Performance: is measured on transit time and response time. The performance depends upon number of users, type of transmission medium, the capabilities of Hardware and the efficiency of the Software

Reliability: is measured by frequency of failure, the time it takes a link to recover from a failure

Security: Protection from un-authorised access and Viruses. At lowest level the protection is user identification codes & passwords. At highest levels the protection is encryption techniques.


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Network Criteria

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Computer networks can be used for several purposes Sharing hardware e.g. CD drives, Printers, Hard drives etc.

Sharing files, data, and information

Sharing software.

Facilitating communications.

e.g. Applications SW, System SW, Drivers etc.

Network Usage

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Networks may be classified according to a wide variety of characteristics

Based on Connection method

Wired Networks

Twisted pair

Co-axial cable

Optical fiber

Wireless Networks

Satellite Link (VSAT)

Wireless LAN (Wi-Fi, Wi-Max)

Infrared Networks (Blue tooth)

Network Classification

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Networks are classified based on functional relationship(network architecture)

Host Based Network (Dumb terminals)

Client Server Networks

Peer to Peer Networks


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Local Area Network(LAN)

Networks are classified based on physical scope


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Metropolitan Area Networks(MAN)

Wide Area Networks(WAN)


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Bus Topology

ii. Ring Topology

Networks are classified based on topology


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Star Topology

Mesh Topology


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Standards

De facto (by fact)

De jury (by law)

Proprietary Non-proprietary


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Datacom Standards

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The Standard Organizations

1. ISO (International Standard Organization)

2. ITUT (International Telecommunication Union) Formerly known as CCITT 3. ANSI (American National Standard Institute)

4. IEEE (Institute of Electrical & Electronic Engineers)

5. EIA / TIA ( Electronic Industries Association / Telecommunication Industries Association)

6. IEC (International Electro Technical Commission)

7. ISOC & IETF (Internet Society & Internet Engineering Task Force) J.Vijay Kumar, INW-2, Network Lab Datacom Basics

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ITU-T: It is an agency of united nations, it sets standards for modems & switching networks

ITU-T STANDARDS

V-Series X-Series

V.24, V.32, V.33, V.35

Which defines data transmission over phone lines

X.21, X.25, X.400

Which defines data transmission Over switching digital networks E-mail & directory services, ISDN Broadband(or) information super highway J.Vijay Kumar, INW-2,


ITU-T

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ISO: It is a non governmental organization based in Geneva, the most significant activities is its work on open systems, which defines the protocols that would allow any two computers to communicate independent of their architecture

ANSI: It is a private agency, it sets up the standards for FDDI (which is one of the LAN interface) & ASCII (which is used by many computers for storing information.

IEEE: It is the largest professional organization for developing standards for LAN called as IEEE 802

e.g. 802.3 for Ethernet LAN J.Vijay Kumar, INW-2, Network Lab

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IEEE Standards

These are also called as LAN (Ethernet) standard and represented with IEEE 802

IEEE 802.1 defines about Ethernet 10 Base 2

IEEE 802.2 defines about Ethernet 10 Base 5

IEEE 802.3 defines about Ethernet 10 Base T

IEEE 802.4 defines about Ethernet 100 Base t

IEEE 802.5 defines about Gigabit Ethernet

IEEE 802.11 defines about Wire-less LAN J.Vijay Kumar, INW-2, Network Lab

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IEEE 802.10 Defines standard for interoperable LAN/MAN IEEE 802.11 Defines standards for wire-less media access control

IEEE 802.12 Demand priority access method for 100 Mbps LAN

(100 BASE VG or 100 VG or 100 VG-Any LAN)

IEEE 802.13 13 avoided

IEEE 802.14 Cable TV based broad band communication


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IEEE Standards

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EIA/TIA: Defines physical connection interfaces and Electronic signaling specifications for data communications Their most well known standard is the RS-232(EIA-232), EIA-449 & EIA-530 defines serial transmission between two digital devices (i.e. computer to modem) IEC: It is a non governmental agency devising standards for data processing and safety in office equipments. It has devised a compression standard for images like JPEG ISOC & IETF: Internet Society concentrates on user issues Including enhancement to the TCP/IP protocol IETF focuses on technical Internet issues (hardware & software) it Developed SNMP(Simple Network Management Protocol)


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EIA Standards

Defines physical connection interfaces and electrical Signaling specifications for data-communication

e.g. EIA-232, EIA-449 EIA-232 is a 25 wire cable 25 pin DB-25 connector Transmits at a speeds of 20KBPS, The distance should not exceed 15mtr (or) 50 feet NRZ coding is used EIA-449 is a 37 pin connector Transmits data speed of 10MBPS The distance should not exceed 40 feet The above standard defines serial transmission between two

digital devices e.g. computer to modem


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V.35 Standard

It is normally used in WAN interfaces

Commonly used for above 64 Kbps

Generally called as Digital interface

It can transmit @ 100 Kbps for a distance of 600 to 1200

meters

It can transmit @ 10 Mbps for a distance of 90 meters

It is a 34-pin a male connector, out of which only 18

pins are used J.Vijay Kumar, INW-2, Network Lab

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G.703 Standard

Basically it is a PCM standard

Originally described for voice over digital networks

Used on MUX side

Works over 64 Kbps speed(digital)


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MODEMS

Bell modems ITU-T modems Baud rate Bit rate Modulation 103

1200 1200 V.23

4-PSK 1200 600 V.22

FSK 300 300 V.21

202

4-PSK 2400 1200 V.26

FSK

16-QAM 9600 2000 V.29

8-PSK 4800 1600 V.27

112

209

201

208

2400 28800 4096-QAM V. 34


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The Universal Serial Bus, (USB) is a universal port that allows you to connect external devices to Windows and Macintosh computers. USB devices such as Digital Cameras, Mice, Scanners, Printers and a

host of others. The USB standard supports data transfer rates of 12Mbps (million bits per second). Aside from speed advantages, USB devices can be connected or disconnected without the need to restart the computer, also known as hot swappable. USB 2.0 is the next generation of USB that simply builds off its

predecessor even looking the same. USB 2.0 does however offer speeds of 40x faster then the original and is also backward compatible with USB devices

USB


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Fire-Wire IEEE 1394

The IEEE 1394 standard for the High Performance Serial Bus, also called Fire-Wire.

It is a serial data transfer protocol and interconnection system. The main feature of the Fire-Wire that assures its adoption for the digital video and audio (A/V).

Fire wire interface is capable of supporting various high-end

digital A/V applications, such as consumer A/V device control and signal routing, Digital Video (DV) editing, home networking, and more than 32 channels of digital mixing


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High data transfer rate up to 50 MB/s (400 Mbps), which is about 30 times faster than USB.

Supports up to 63 devices (16 - daisy chained) with

cable length up to about 4.5 m (14 feet).

Hot-pluggable (like USB). No need to turn of your device to connect or disconnect, and you don't need to reboot your PC. Also, Fire-wire is a plug-and-play bus.

Fire-wire cables are very easy to connect (Like USB). J.Vijay Kumar, INW-2,


Advantages of Fire-Wire IEEE 1394

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OSI Layers

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OSI Model – History, Origin, Purpose

Introduced in 1970 by ISO, that covers all aspects of network Communications is the open systems Interconnections model . An Open system is a set of protocols that allows any two different

systems to communicate regardless of their underlying architecture. The purpose of the OSI model is to show how to facilitate

communication between different systems without requiring changes to the logic of the underlying hardware and software. The OSI model is not a protocol ; it is a model for understanding

and designing a network architecture that is flexible, robust and interoperable. The OSI model is a seven-layer framework that allows

communication between all types of computer systems

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The OSI Model is a way of thinking about how networks 'work'. The OSI Model is a theoretical model--it is not a technology, it is

not a protocol, it is not a program or software. The OSI Model sorts out network communication functions into

layers The OSI Model does not specify how a layer will work internally--

that is a matter left to the programmers. The OSI Model specifies how layers should talk to each other. The OSI Model specifies that any layer's processes should be

invisible to the layer above it, and below it. The OSI Model defines how information should be handled when

being transported over a network. The OSI Model defines how software should interact with the

network.

What is OSI Model ?

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Learning the OSI Model helps us to understand what functions occur where and when

The OSI Model helps us to understand how a Web browser works The OSI Model helps us to understand what Internet Protocol does

and how it works The OSI Model helps us to understand why we need ARP The OSI Model helps us to understand what is MAC address Learning the OSI Model makes it easier to learn. Learning the OSI Model makes it easier to perform

troubleshooting. Learning the OSI Model makes it easier to troubleshoot any

problem, including computer problems. Learning the OSI Model makes it easier to communicate with other

technical people and discuss technical issues.

Why Should We Learn the OSI model ?

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Network architecture based on the OSI model

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OSI Layers 51

OSI Model Layers

Application

Presentation

Session

Transport

Network

Data Link

Physical

Layer - 7

Layer - 6

Layer - 5

Layer - 4

Layer - 3

Layer - 2

Layer - 1

Upper Layer

or

Software

Layer

Lower Layer

or

Hardware Layer

Heart of OSI

OSI Layers

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Application Layer is

responsible for providing

Networking Services to user.

It also known as Desktop Layer.

Identification of Services is done

using Port Numbers.

Ports are nothing but Socket i.e.

Entry and Exit Point to the

Layer

Total No. Ports 0 – 65535

Reserved Ports 0 – 1023

Open Ports 1024 – 65535

Application

Presentation

Session

Transport

Network

Data Link

Physical

Application

Application Layers

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Applications

Computer Applications:

MS Office, Data Base, Presentation Graphics, Animations etc.

Network applications:

Electronic Mail, File Transfer, Client Server Processor, Network Management.

Inter Network Applications:

WWW, Internet Browsers, Conference (A+V+D).

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Example of HTTP request

Client Web Server

HTTP Request

http:// www.iriset.ac.in

Webpage

HTTP Request

Listen on

Port 80

Sending HTTP Reply

Webpage

Received HTTP Reply

http://www.iriset.ac.in

Webpage

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http (webpage/port no.80) request

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FTP Request

ftp://ftp.microsoft.com

FTP Request

Listen on

Port 21

Sending FTP Reply

Received FTP Reply

ftp://ftp.microsoft.com

Client FTP Server

ftp (file transfer port no.21) request

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Service Port No.

HTTP 80

FTP 21

SMTP 25

TELNET 23

TFTP 69

HTTPS 443

Port numbers & Services

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Application

21 80 25 67 53 69

How data flows through Application Layer from Application Layer

Data

Presentation

Session

Transport

Network

Data Link

Physical

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Presentation Layer

Presentation Layer is responsible for converting data into standard format.

Examples : ASCII, EBCDIC, JPEG, MPEG, BMP, MIDI, WAV, MP3

Following tasks are perform at Presentation layer :

Encoding – Decoding

Encryption – Decryption

Compression – Decompression

Application

Presentation

Session

Transport

Network

Data Link

Physical

Presentation

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How data flows through Presentation Layer

Data

Data Application

Presentation

Session

Transport

Network

Data Link

Physical

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Session Layer is responsible establishing, maintaining and terminating session.

Session ID also works at Session Layer.

Examples :

RPC Remote Procedure Call

SQL Structured Query language

NFS Network File System

Application

Presentation

Session

Transport

Network

Data Link

Physical

Session

Session Layer

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Data

Data

Data

Application

Presentation

Session

Transport

Network

Data Link

Physical

How data flows through Session Layer

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Transport Layer is responsible for end-to-end connectivity. It is also known as heart of OSI Layers. Following task are performed at Transport Layer : -

Identifying Service

Multiplexing & De-multiplexing

Segmentation

Sequencing & Reassembling

Flow Control

Error Correction

Application

Presentation

Session

Transport

Network

Data Link

Physical

Transport

Transport Layer

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Service point addressing.

Segmentation and reassembly.

Connection control i.e. end to end connection

Flow control & Error control.

The Transport layer is responsible for the delivery of a message from one process to another with reliability.

Transport Layer

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How data flows from Transport

Layer

Data

Data

Data

Data TH Segment

Application

Presentation

Session

Transport

Network

Data Link

Physical

How data flows through Transport Layer

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OSI Layers 66

Identifying Service

Transmission Control Protocol

Connection Oriented

Acknowledgement

Reliable

Slower

Port No. 6

e.g. HTTP, FTP, SMTP

User Datagram Protocol

Connection less

No Acknowledgement

Unreliable

Faster

Port No. 17

e.g. DNS, DHCP, TFTP

TCP UDP

Transport Layer Protocols

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OSI Layers 67

Application

Presentation

Session

Multiplexing & De-multiplexing

21 80 25 67 53 69

Transport

TCP - 6 UDP - 17

Network

Data Link

Physical

Transport Layer Protocols with port numbers

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Network Layer

Network Layer is responsible for providing best path to data to reach destination. Logical Addressing sits on this layer. Device working on Network Layer is Router.

It is divided into two parts

Routed Protocols

e.g. IP, IPX, Apple Talk.

Routing Protocols

e.g. RIP, IGRP, OSPF, EIGRP

Application

Presentation

Session

Transport

Network

Data Link

Physical

Network

Network Layer

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Logical addressing.

Routing and best path selection.

Routes packets according to unique network device addresses.

Provides flow & congestion control.

Network layer is responsible for the delivery of individual packets from source (Server) to destination (Host).

Network Layer

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OSI Layers 70

How data flows from Network Layer

Data

Data

Data

Segment

Segment

N

H

e.g. Router

Packet

Application

Presentation

Session

Transport

Network

Data Link

Physical

How data flows through Network Layer

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Routing Protocols

A

www.iriset.ac.in

How Packet is routed from source to Destination

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Datalink Layer

Datalink Layer is divided into two Sub Layers :

LLC – Logical Link Control

It talks about Wan protocols

e.g. PPP, HDLC, Frame-relay

MAC – Media Access Control

It talks about Physical Address.

It is 48 bit Addressing

i.e. 12 digit Hexadecimal Number.

It is also responsible for Error Detection

Device working on Data Link Layer is Switch, Bridge, NIC.

Application

Presentation

Session

Transport

Network

Data Link

Physical

Data Link

Datalink Layer

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Access to Media

Physical addressing and network topology.

Flow control, Error control & Access control.

Data link layer is responsible for moving frames from hop to hop or node to node & its delivery. It defines procedure for operating the communication links.

Datalink Layer

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OSI Layers 74

e.g. Switch

How data flows from Data Link Layer

Data

Data

Data

Segment

DH

Packet

DT

Application

Presentation

Session

Transport

Network

Data Link

Physical

Packet Packet Frame

How data flows through Datalink Layer

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Physical Layer

Physical Layer is responsible for electrical, mechanical or procedural checks.

Data will be converted in Binary that is 0’s & 1’s.

Data will be in the form of electrical pulses if it is Coaxial or Twisted Pair cable and in the form of Light if it is Fiber Optic Cable.

Devices working at Physical Layer are Hubs, Repeaters, Cables, Modems etc.

Application

Presentation

Session

Transport

Network

Data Link

Physical Physical

Physical Layer

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Physical characteristics of interfaces & medium.

Representation of bits.

Data rate or transmission rate.

Synchronization of bits.

Line configurations.

Physical topology

Transmission modes

Physical layer is responsible for bit to bit binary transmission.

Physical Layer

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OSI Layers 77

How data flows from Physical Layer

Data

Data

Data

Segment

Packet

Frame

Bits

e.g. Hub

Application

Presentation

Session

Transport

Network

Data Link

Physical

How data flows through Physical Layer

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OSI Layers 78

Segment

Packet

Frame

A B

Packet

Data

Data

Data

Bits

Data

Segment

Data Encapsulation & De-capsulation

Packet

Data

Data

Data

Application

Presentation

Session

Transport

Network

Data Link

Physical

Application

Presentation

Session

Transport

Network

Data Link

Physical Bits

DH DT

NH

TH Segment

Packet

DT Packet DH DT DH

NH Segment NH

TH Data TH

Frame Packet

How data transmits from source to destination using OSI layer

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OSI Layers 79

Application

Transport

Internet

Network

Access

Comparing OSI with TCP/IP Layers

OSI Layers TCP/IP Layers

Application

Presentation

Session

Transport

Network

Data Link

Physical

OSI & TCP / IP Layers

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Objectives of layers

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Application

Presentation

Session

Transport

Network

Data Link

Physical

Virtual terminal SW for user appl. and services

Syntax and Semantics

Manages timings and dialogs (Synchronization)

Splits data and passes to NW layer

Controls subnet and does Routing

Checks access ,data and frames

Raw data or Binary transmission

Summary of OSI layers

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Addition of headers & trailers in OSI layers

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TCP/IP

Technically, Transmission Control Protocol (TCP) and Internet Protocol (IP) are two distinct network protocols.

TCP and IP are so commonly used together, though, that TCP/IP has become standard terminology to refer to either *or* both of the protocols.

IP roughly corresponds to the Network layer (layer 3) in the OSI model

TCP corresponds to the Transport layer (layer 4) in OSI.

TCP/IP refers to network communications where the TCP transport is used to deliver data across IP networks.

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TCP/IP

TCP/IP is basically a protocol suit which consists of two protocols TCP and IP. It is also referred to as a protocol stack i.e. a group of protocols that all work together to allow software or hardware to perform a function. It uses four layers that map to the OSI model as follows:

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Why TCP/IP a suite for Internet ?

Can be used to communicate across any set of interconnected networks.

Equally suited for both LAN & WAN communication.

Includes specifications for common applications as e-mail, remote login, terminal emulation, file transfer etc.

File Transfer- TFTP, FTP, NFS

E-mail- SMTP

Remote Login -TELNET, Rlogin

Network Management - SNMP

Name Management - DNS

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TCP/IP Concepts

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Similarities of OSI & TCP/IP Layers

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Both have layered architecture. Layers provide similar functionalities. Both are protocol stack. Both are reference models

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OSI Layers TCP/IP Layers 7 layers 4 layers

Protocols replaceable Not easy

Protocol fitting into the model Does not fit

A guidance tool. A way of implementing OSI model.

Follows vertical approach. Follows horizontal approach.

Provides both connection oriented and connectionless

service.

Provides connectionless service.

Transport Layer is Connection Oriented Transport Layer is both Connection Oriented and

Connection less.

Transport layer guarantees the delivery of packets Transport layer does not guarantee delivery of packets.

Still the TCP/IP model is more reliable

OSI is a generic, protocol independent standard, TCP/IP model is based on standard protocols around

which the Internet has developed. It is a communication

protocol, which allows connection of hosts over a

network.

OSI model defines services, interfaces and protocols

very clearly and makes clear distinction between them.

It is protocol independent.( Explicit & protocol

independent )

In TCP/IP, services, interfaces and protocols are not

clearly separated. It is also protocol dependent.(

Protocol dependent.)

Differences of OSI & TCP/IP Layers

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IPv4 Address

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TCP /IP defined different addresses at different layers

like MAC address at data link layer, for node to node delivery of frames

IP address at network layer, for host to host delivery of packets

PORT address at transport layer, for process to process and application to application communication.

MAC is 48 bit divided in to 6 blocks each contains 8 bits and represented in Hexadecimal form

PORT numbers is 16 bit (65536 numbers)

Out of which 0 to 1023 are Well known port numbers.

1024 to 49151 - Registered ports and 49152 to 65536 - Dynamic or private ports.

IP Address

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IP Addressing

When systems are grouped and networked using shared media, they must be identified with unique LOGICAL numbers and those numbers are called IP address.

The Internet Society(ISOC) , The Internet Corporation for Assigned Names and Numbers (ICANN), The Internet Assigned Numbers Authority IANA and IEEE are responsible for the global coordination of the DNS Root, IP addressing, as well as the Autonomous System Numbers used for routing Internet traffic.

Both IPv4 and IPv6 addresses are generally assigned in a hierarchical manner. Users are assigned IP addresses by Internet service providers (ISPs). ISPs obtain allocations of IP addresses from a local Internet registry (LIR) or National Internet Registry (NIR), or from their appropriate Regional Internet Registry (RIR)

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IP Address is a Logical Address

It works on Network Layer (Layer 3)

Each & every device existing on the network should be given with one IP address

Two Versions of Address Scheme

IP version 4 – 32 bit address

IP version 6 – 128 bit address

IP Address

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IPv1, 2, & 3 would be part of the TCP/IP protocols, of which there were 3 versions before the IP protocol was split of it.

IPv4 is actually the first version of the IP protocol.

IPv5 is an experimental TCP/IP protocol called the Internet Stream Protocol

This IPv5 never really went anywhere because increases in bandwidth made streaming over IPv4 feasible.

So IPv5 was never finalized and they skipped to IPv6.

IP Address

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IP Address allocation / IANA

IANA (Internet Assigned Numbers Authority) www.iana.org allocates IPs (both IPv4 & IPv6) to RIR (Regional Internet Registry)

These RIRs will further distribute the IPs to NIR (National Internet Registry)

These NIRs will further distribute the IPs to LIR (Local Internet Registry)

These LIRs will further distribute the IPs to ISP (Internet Service Provider)

ISPs in turn will provide the IPs to end users/companies/ organizations

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http://www.iana.org/

There are five (5) regional Internet Registry are existing over the globe

These registries are responsible for distributing both IPv4 & IPv6 address.

1.AFRINIC: African Region

2.APNIC: Asia/Pacific Region

3.ARIN: North America Region

4.LACNIC: Latin America and some Caribbean Islands

5.RIPE NCC: Europe, the Middle East, and Central Asia

IP Address allocation / RIR

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Regional Internet Registry (RIRs)

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IPv4 Address / History

IPv4 was introduced in 1981

It was designed with 32 bits

Total number of IPv4 addresses are 232 (4.2 billion)

It is represented as octet form.

During 1980s, very few Companies/Organizations had computer networks, Internet came into existence later on

As more companies & organizations started building networks and Internet started to grow the need for IPv4 addresses to grow

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IPv4 is a 32 bit address and these bits are shown as 4

blocks or octets, and each block or octet will have 8 bits

Total number of IPv4 addresses are 232 (4.2 billion)

Each block or octet of 8 bits is converted into a decimal

number and each decimal is separated by dots.

IPv4 address is represented by dotted-decimal notation

e.g. 192.168.1.1

IPv4 Address

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IPv6 is 128 bit address and these bits are shown as 8 blocks,

and each block will have 16 bits

total address possible are 2128

340,282,366,920,938,463,463,374,607,431,768,211,456

Each block of 16 bits is converted into a 4 digit hexadecimal

number and each hexadecimal is separated by colons

IPv6 address is represented by colon-hex notation

e.g. FEDC:BA98:7654:3210:FEDC:BA98:7654:3210

IPv6 Address

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Bit is a value that will represent either ‘0’ or ‘1’, but 32 bits may be 01010101000001011011111100000001

These 32 bits are shown as 4 octets known as Dotted Decimal Notation

01010101. 00000101. 10111111. 00000001

1st Octet 2nd Octet 3rd Octet 4th Octet

IPv4 Representation

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Taking Example for First Octet :

Total 8 bits, bit value can ‘0’s & 1’s

i.e. 28 = 256 combination

27 26 25 24 23 22 21 20

0 0 0 0 0 0 0 0 = 0

0 0 0 0 0 0 0 1 = 1

0 0 0 0 0 0 1 0 = 2

0 0 0 0 0 0 1 1 = 3

0 0 0 0 0 1 0 0 = 4

1 1 1 1 1 1 1 1 = 255

Total IP Address Range

0 . 0 . 0 . 0

to

255.255.255.255

IPv4 Representation

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Total IPv4 Address (4.2 billion) are divided into 5 Classes

CLASS A

CLASS B

CLASS C

CLASS D

CLASS E

LAN & WAN

Multicasting

Research & Development

IPv4 Classes

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Broadcast messages is sent all the stations or nodes in the

network.

By default IPv4 supports broadcast, broadcast is the enemy

of the network, it is un-desirable in the network, wherever

feasible try to reduce the scope of the broadcast.

Unicast messages is sent to one station only in the

network. Unicast is most desirable in the network, but

consumes more bandwidth.

Multicast messages are sent to a group of stations, used

mostly in real-time applications, more software specific.

e.g. video conference, stock market updates, live

telecast

Broadcast, Unicast & Multicast

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IPv4 address / Priority Bits Concept

To identify the range of each class, Priority Bits Concept is used

Priority Bits are the left most bits in the First Octet of IP address

CLASS ‘A’ priority bit is 0

CLASS ‘B’ priority bit is 10

CLASS ‘C’ priority bit is 110

CLASS ‘D’ priority bit is 1110

CLASS ‘ ‘E priority bit is 1111

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In Class ‘A’ the first bit in first octet, is reserved and it’s value is ‘0’ the value of this bit is not going to change, but remaining ‘7’ bits value may change.

0xxxxxxx. xxxxxxxx. xxxxxxxx. xxxxxxxx

27 26 25 24 23 22 21 20

0 0 0 0 0 0 0 0 = 0

0 0 0 0 0 0 0 1 = 1

0 0 0 0 0 0 1 0 = 2

0 0 0 0 0 0 1 1 = 3

0 0 0 0 0 1 0 0 = 4

0 1 1 1 1 1 1 1 = 127

Class A Range

0 . 0 . 0 . 0

to

127.255.255.255

Except

0.X.X.X (used for default network)

&

127.X.X.X (used for universal loop back

address)

IPv4 address/Class ‘A’/Priority bit ‘0’

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In Class ‘B’ the first two bits in first octet, is reserved and value is ‘10’ the value of these bits are not going to change, but remaining ‘6’ bits value may change.

10xxxxxx. xxxxxxxx. xxxxxxxx. xxxxxxxx

27 26 25 24 23 22 21 20

1 0 0 0 0 0 0 0 = 128

1 0 0 0 0 0 0 1 = 129

1 0 0 0 0 0 1 0 = 130

1 0 0 0 0 0 1 1 = 131

1 0 0 0 0 1 0 0 = 132

1 0 1 1 1 1 1 1 = 191

Class B Range

128. 0 . 0 . 0

to

191.255.255.255

IPv4 address/Class ‘B’/Priority bits’10’

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In Class ‘C’ the first three bits in first octet, is reserved and value is ‘110’ the value of these bits are not going to change, but remaining ‘5’ bits value may change.

110xxxxx. xxxxxxxx. xxxxxxxx. xxxxxxxx

27 26 25 24 23 22 21 20

1 1 0 0 0 0 0 0 = 192

1 1 0 0 0 0 0 1 = 193

1 1 0 0 0 0 1 0 = 194

1 1 0 0 0 0 1 1 = 195

1 1 0 0 0 1 0 0 = 196 1 1 0 1 1 1 1 1 = 223

Class C Range

192. 0 . 0 . 0

to

223.255.255.255

IPv4 address/Class ‘C’/Priority bits’110’

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In Class ‘D’ the first four bits in first octet, are reserved and value is ‘1110’ the value of these bits are not going to change, but remaining ‘4’ bits value may change.

1110xxxx. xxxxxxxx. xxxxxxxx. xxxxxxxx

27 26 25 24 23 22 21 20

1 1 1 0 0 0 0 0 = 224

1 1 1 0 0 0 0 1 = 225

1 1 1 0 0 0 1 0 = 226

1 1 1 0 0 0 1 1 = 227

1 1 1 0 0 1 0 0 = 228 1 1 1 0 1 1 1 1 = 239

Class D Range

224. 0 . 0 . 0

to

239.255.255.255

IPv4 address/Class ‘D’/Priority bits’1110’

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In Class ‘E’ the first four bits in first octet, are reserved and value is ‘1111’ the value of these bits are not going to change, but remaining ‘4’ bits value may change.

1111xxxx. xxxxxxxx. xxxxxxxx. xxxxxxxx

27 26 25 24 23 22 21 20

1 1 1 1 0 0 0 0 = 240

1 1 1 1 0 0 0 1 = 241

1 1 1 1 0 0 1 0 = 242

1 1 1 1 0 0 1 1 = 243

1 1 1 1 0 1 0 0 = 244 1 1 1 1 1 1 1 1 = 255

Class E Range

240. 0 . 0 . 0

to

255.255.255.255

IPv4 address/Class ‘E’/Priority bits’1111’

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Class C network id host11 0

Network Prefix24 bits

Host Number8 bits

bit # 0 1 23 242 313

Class B 1 network id host

bit # 0 1 15 162


Host Number16 bits

0

31

Class A 0


bit # 0 1 7 8

Host Number24 bits

31

Class D multicast group id11 1

bit # 0 1 2 313

0

4

Class E (reserved for future use)11 1

bit # 0 1 2 313

1

4

0

5

IPv4 address/Classes

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CLASS FROM TO

A 0.0.0.0 127.255.255.255

B 128.0.0.0 191.255.255.255

C 192.0.0.0 223.255.255.255

D 224.0.0.0 239.255.255.255

E 240.0.0.0 255.255.255.255

IPv4 address/Classes-Range

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Every IPv4 address (32 bits) is a combination of network ID and Host ID

e.g. 192.168.1.1/24 is having two parts

192.168.1.0 (MSB ’24’ bits) is a network ID

0.0.0.1 (LSB ‘8’ bits) is a Host ID

Subnet Mask will extract (or) differentiate the network ID from the given IP address

In the LAN network, by keeping the subnet mask same for all the systems in the network, thereby keeping the network IDs same, the data & resouces can be shared easily among these LAN systems

IPv4 address/Network ID & Host ID

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e.g. IP address is represented as 192.168.1.1/24 , out of this we have to find out what is network ID & what is host ID, here subnet mask will help you to find out network ID. Subnet mask bits are equivalent to Network bits and they

are ’24’ & these bits value is always ‘1’ & host bits are ‘8’ and bit value is ‘0’

i.e. 11111111.11111111.11111111.00000000 Hence, now decimal equivalent of this subnet mask is 255.255.255.0

To extract the network ID from the given IP address, the subnet mask will do the bit-vise ANDing with the IP

(IP) 192.168.1.1 = 11000000.10101000.00000001.00000001

(S/M) 255.255.255.0 = 11111111.11111111.11111111.00000000 Bit vise ANDing ----------------------------------------------------------

(N/ID)192.168.1.0 = 11000000.10101000.00000001.00000000

-----------------------------------------------------------

IPv4 address/Subnet Mask

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Subnet Mask is of two types. They are

Default Mask

Customized Mask

The networks which uses the default mask, are called as Class-full networks, here only IP address is mentioned no information of masking bits is given, but based on the IP address 1st byte value, the subnet mask is automatically added.

e.g. 192.168.1.1

Here subnet mask is automatically added as 255.255.255.0

The networks which uses the customized mask, are called as Class-less networks, here along with IP address, the masking bits is also mentioned in CIDR notation.

e.g. 192.168.1.1 /26 Here subnet mask is calculated as 255.255.255.192

e.g. 192.168.1.1 /27 Here subnet mask is calculated as 255.255.255.224

IPv4 address/Subnet Mask

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The network prefix identifies a network and the host number identifies a specific host work).

How do we know how long the network prefix is?

Before 1993: The network prefix is implicitly defined (see class-

based addressing) /or class-full network After 1993: The network prefix is indicated by a netmask (see CIDR

notation) /or class-less network

network prefix host number

IPv4 address/Network Prefix & Host Number

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CLASS ‘A’ is written as N.H.H.H

CLASS ‘B’ is written as N.N.H.H

CLASS ‘C’ is written as N.N.N.H

IPv4 address/Network bits/Host bits

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Class A Octet Format is N.H.H.H

Network bits : 8; Host bits : 24

No. of Networks

= 28-1 (-1 is Priority Bit for Class A)

= 27 = 128

= 128-2 (-2 is for 0 & 127 Network )

= 126 Networks

No. of Host

= 224 – 2 (-2 is for Network ID & Broadcast ID)

= 16777216 – 2

= 16777214 Hosts/Network

CLASS A

126 Networks &

16777214 Hosts

IPv4 address/Class ‘A’/Network bits/Host bits

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Class B Octet Format is N.N.H.H

Network bits : 16 Host bits : 16

No. of Networks

= 216-2 (-2 is Priority Bit for Class B)

= 214

= 16384 Networks

No. of Host


= 65536 – 2

= 65534 Hosts/Network

CLASS B

16384 Networks &

65534 Hosts

IPv4 address/Class ‘B’/Network bits/Host bits

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Class C Octet Format is N.N.N.H

Network bits : 24 Host bits : 8

No. of Networks

= 224-3 (-3 is Priority Bit for Class C)

= 221

= 2097152 Networks

No. of Host


= 256 – 2

= 254 Hosts/Network

CLASS C

2097152 Networks &

254 Hosts

IPv4 address/Class ‘C’/Network bits/Host bits

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Class A : N.H.H.H

11111111.00000000.00000000.00000000

Default Subnet Mask for Class A is 255.0.0.0

Class B : N.N.H.H

11111111.11111111.00000000.00000000

Default Subnet Mask for Class B is 255.255.0.0

Class C : N.N.N.H

11111111.11111111.11111111.00000000

Default Subnet Mask for Class C is 255.255.255.0

IPv4 address/Class ‘A’, ‘B’ & ‘C’/Default Subnet Mask

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Network address: is represented with all bits as ZERO in the host portion of the address

Broadcast address: is represented with all bits as ONES in the host portion of the address

Valid IP Addresses: lie between the Network Address and the Broadcast Address. Only Valid IP Addresses are assigned to hosts/clients

IPv4 address/network address/broadcast address/valid IP address

Only Valid IP addresses are allotted to hosts/clients

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Class A : N.H.H.H

Network Address :

0xxxxxxx.00000000.00000000.00000000

Broadcast Address :

0xxxxxxx.11111111.11111111.11111111

Class A 10.0.0.0

10.0.0.1

10.0.0.3

10.255.255.254

10.255.255.255 Broadcast Address

Network Address

Valid IP Addresses

Class ‘A’/ network address/broadcast address/valid IP address

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Class B : N.N.H.H

Network Address :

10xxxxxx.xxxxxxxx.00000000.00000000

Broadcast Address :

10xxxxxx.xxxxxxxx.11111111.11111111

Class B 172.16.0.0

172.16.0.1

172.16.0.2

172.16.255.254


Network Address

Valid IP Addresses

Class ‘B’/ network address/broadcast address/valid IP address

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Class C : N.N.N.H

Network Address :

110xxxxx.xxxxxxxx.xxxxxxxx.00000000

Broadcast Address :

110xxxxx.xxxxxxxx.xxxxxxxx.11111111

Class C 192.168.1.0

192.168.1.1

192.168.1.2

192.168.1.254


Network Address

Valid IP Addresses

Class ‘C’/ network address/broadcast address/valid IP address

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There are certain addresses in each class of IP address that are reserved for LAN. These addresses are called private addresses. These addresses are not routable & invalid over the Internet.

They can be used for: LAN, Private Networks, home & office networks, ATM machines, networks not connected to Internet.

Class A

10.0.0.0 to 10.255.255.255 Class B

172.16.0.0 to 172.31.255.255 Class C

192.168.0.0 to 192.168.255.255

IPv4 address/Private IP addresses (PIPA addresses)

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Public IP addresses vs Private IP addresses

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Reserved Address Block/IANA

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Universal Loopback address All addresses of 127.0.0.0 network (from 127.0.0.1 to 127.255.255.255 ) are reserved for testing the integrity of your NIC card, called as universal loopback address. Universal network All the bit numbers (32) is set to all zero’s, e.g., 0.0.0.0 used for default network. Universal host or universal broadcast address All the bit numbers (32) is set to all one’s, e.g., 255.255.255.255 used for sending the broadcast messages. Network Address In a network, if all the host bits value is set to zero’s , this address is used in the Routing Broadcast Address In a network, if all the host bits value is set to one’s , this address is used for sending broadcast messages to all the hosts in that network Automatic Private IP addresses (APIPA) In a network, if there is a DHCP server is there, all the hosts will get the IP address automatically, in the event of DHCP server failure, all the hosts in the network will get the IP address in the range of 169.254.0.0, these addresses are not routable, but by using these address local LAN resources can be shared.

Reserved or Special IPv4 Address

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IP address to a host can be assigned in two ways Static method Dynamic method

Static IP address is a permanent number assigned to a computer by Network administrator. Static IP addresses are useful for gaming, website hosting or Voice over Internet Protocol (VoIP) services. Speed and reliability are key advantages. Assigning static IP addresses is a time consuming job, will

burden the Network administrator. Dynamic IP addresses are assigned to a computer by

DHCP Server, using DHCP protocol, with no time entire network can be configured, it easies the administrative job. Static IP addresses pose potential security weak points

since hackers will have sufficient time to attack the network.

Assigning an IP address to a host

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How DHCP Works/DORA process

A dynamic IP address is an automatically configured IP address assigned by DHCP server to every new network node.

DHCP server uses the DORA (Discover, Offer, Request & Acknowledge) process for assigning IP address to the node.

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How DNS works

DNS server will resolve URL address into IP address, to access Internet, these DNS servers will be maintained by ISPs

IRIS

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DHCP and DNS Services

Parameters DHCP DNS

Basic A protocol for assigning IP address

to the host statically or dynamically.

An address resolving mechanism.

Related protocols UDP UDP and TCP

Server

DHCP server is responsible for allocating the temporary addresses to the client computer for a lease

time, and then extending the lease according to the requirement.

DNS server is responsible for accepting the queries

through client and responding back with the

results.

Working methodology Centralized Decentralized

Features

1. Provide additional information such as IP addresses of the host

and Subnet mask of the computer. 2. Assigns IP to host for a

particular lease time.

1. Coverts symbolic names into IP address and vice-

versa. 2. Used for locating active directory domain servers.

Advantage Reliable IP address configuration

and reduced network administration.

Eliminate the need to remember the IP address;

instead, the domain name is used for the web address.

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MAC, IP, Port address, DHCP & DNS Services

MAC Address is how your system is uniquely physically identified for networking;

IP Addressing is used to locate and identify networking devices on TCP/IP networks.

Port Address is used for end to end process or service connectivity Data to flow to its logical (software) endpoint, the port number identifies what is being listened to across the network and connects that to its software that is useful.

DHCP server assigns the IP addresses to client computers, while DNS server resolves them.

They are two essential technology developed for us to use the network or Internet conveniently.

In addition, both DHCP and DNS are essential tools in the network administrator's toolkit for managing all the IP devices on a corporate network.

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Problems with Class-full IP Addresses

Flat address space. Routing tables on the backbone Internet need to have an entry for each network address.

When Class C networks were widely used, this created a problem.

By the 1993, the size of the routing tables started to outgrow the capacity of routers.

Too few network addresses for large networks

Class A and Class B addresses were gone

Limited flexibility for network addresses:

Class A and B addresses are overkill (>64,000 addresses)

Class C address is insufficient (requires 40 Class C addresses)

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CIDR - Classless Inter Domain Routing

Goals: New interpretation of the IP address space Restructure IP address assignments to increase efficiency

Permits route aggregation to minimize route table entries

CIDR:

Abandons the notion of classes Key Concept: The length of the network prefix in the IP

addresses is kept arbitrary

Consequence: Size of the network prefix must be provided with an IP address CIDR notation allows to drop trailing zeros of network

addresses: 192.0.2.0/18 can be written as 192.0.2/18

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Dividing a Single Network into Multiple Networks.

Sub-netting is done to conserve the IP addresses and reducing the broadcast scope

Sub-netting is done by barrowing or transferring some of the host bits towards the network

After sub-netting the network is called classless network

Classless networks is represented in CIDR (Classless Inter Domain Routing)notation

IPv4 address/ Sub-netting

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Basic Idea of Sub-netting

Split the host number portion of an IP address into a subnet number and a host number.

Result is a 3-layer hierarchy

Subnets can be freely assigned within the organization Internally, subnets are treated as separate networks Subnet structure is not visible outside the organization

network prefix host number

subnet number network prefix host number

extended network prefix IRIS

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128.143.0.0/16 is the IP address of the network

128.143.137.0/24 is the IP address of the subnet or sub-network

128.143.137.144 is the IP address of the host

255.255.255.0 (or) ffffff00 is the subnet mask of the host

When sub-netting is used, one generally speaks of a “subnet mask” (instead of a net mask) and a “subnet” (instead of a network)

Use of sub-netting or length of the subnet mask if decided by the network administrator

Consistency of subnet masks is responsibility of administrator

Basic Idea of Sub-netting/Subnet Mask

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e.g. A division is having 100 PC

Which Class IP addresses you will using in the network ?

Answer : Class ‘C’ / Private IP address / 192.168.1.0/24

In that division we have five (5) departments with 20 PCs each

The IP Planning for these five departments of the division with the IP address 192.168.1.0/24 is S&T 192.168.1.1 to 192.168.1.20

192.168.1.21 to 192.168.1.40 ENG

ELECT 192.168.1.41 to 192.168.1.60

MECH 192.168.1.61 to 192.168.1.80

ACCOUNTS 192.168.1.81 to 192.168.1.100

IPv4 address/ Sub-netting Planning

With the above IP Planning all the departments can access each other & all the departments are in one broadcast domain results in poor performance and security breach.

IRIS

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Administration Requirement

Inter-department communication should not be possible ?

Solution: allocate a different Network IDs to each Department

S&T 192.168.1.1 to 192.168.1.20

192.168.2.1 to 192.168.2.20 ENG

ELECT 192.168.3.1 to 192.168.3.20

MECH 192.168.4.1 to 192.168.4.20

ACCOUNTS 192.168.5.1 to 192.168.5.20

With the different network IDs for each department the administrative requirement of Inter departmental communication will not be possible, hence administrative requirement is fulfilled.


IRIS

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Problem with the allotment of different network IDs to each department will result in

Wastage of IP addresses (Each department wastes about 234 IP addresses, that comes to a total approximately more than 1000 IP addresses )

Broadcast scope is increased, security breach Solution: Divide this 192.168.1.0/24 network into five (5)

subnets and allocate each subnet to each department To have five (5) subnets, transfer 3 host bits towards

network side, now the network bits becomes 27 (24+3) and host bits becomes 5 (8-3), now network becomes classless & network is represented with CIDR notation as 192.168.1.0/27


IRIS

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In any network / subnet there will be four (4) parameters to be calculated. They are Subnet Mask Network ID Broadcast ID Valid IP address or range

Considering the requirement of five subnets for five departments.

The Network is represented as 192.168.1.0/27 Network bits = 27 (original network bits 24 + 3 transferred

bits), Host bits in each network = 5 Total subnets = 23 = 8 subnets Total no. of hosts in each subnet is = 25- 2 = 32-2 = 30

hosts (-2 to be done for not considering Network & Broadcast

address) Subnet Mask bits = Network bits = 27 The decimal equivalent Subnet Mask = 255.255.255.224


IRIS

ET

Now sub-netting to be done for the network 192.168.1.0/24

The sub-netted network is 192.168.1.0/27(there will be 8 subnets)

Subnet Mask: 11111111. 11111111. 11111111.11100000 Subnet Mask: 255.255.255.224

Network ID for 1st subnet: 192.168.1.00000000 Network ID for 1st subnet : 192.168.1.0

Broadcast ID for 1st subnet: 192.168.1.00011111 Broadcast ID for 1st subnet: 192.168.1.31 Valid IP range for this 1st subnet: 192.168.1.1

to 192.168.1.30

IPv4 address/ Sub-netting Planning/1st Subnet

Host bits

Network bits

Host bits

Network bits

30 Host

s This Subnet may be allotted to S&T department

IRIS

ET






to 192.168.1.62

IPv4 address/ Sub-netting Planning/2nd Subnet

Host bits

Network bits

Host bits

Network bits

30 Host

s This Subnet may be allotted to Engineering department

IRIS

ET






to 192.168.1.94

IPv4 address/ Sub-netting Planning/3rd Subnet

Host bits

Network bits

Host bits

Network bits

30 Host

s This Subnet may be allotted to Electrical department

IRIS

ET






to 192.168.1.126

IPv4 address/ Sub-netting Planning/4th Subnet

Host bits

Network bits

Host bits

Network bits

30 Host

s This Subnet may be allotted to Mechanical department

IRIS

ET




Network ID for 1st subnet: 192.168.10000000 Network ID for 1st subnet : 192.168.1.128


to 192.168.1.158

IPv4 address/ Sub-netting Planning/5th Subnet

Host bits

Network bits

Host bits

Network bits

30 Host

s This Subnet may be allotted to Accounts department

IRIS

ET

Sub-netting is done with the help of customized mask and there are two types of customized masks: FLSM & VLSM Fixed Length Subnet Mask (FLSM) will provide equal & fixed

no. of hosts in each subnet, here subnet mask is same for all the subnets, this is the most popular type of customized mask. Variable Length Subnet Mask (VLSM) will provide variable

no. of hosts in each subnet based on the subnet bits. Here subnet mask is different for different subnets. Here better utilization of IP addresses & the broadcast scope is drastically reduces. VLSMs provide the capability to include more than one

subnet mask within a major network.

Sub-netting /FLSM & VLSM

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VLSM: The process of sub-netting a network and further & further sub-netting that network, to meet your needs

Example: 1.Network 10.0.0.0/8 is sub-netted to10.1.0.0/16, by barrowing 8 bits from the host side to create 256 subnets 2.Sub-networked 10.1.0.0/16 is further sub-netted to10.1.1.0/24, by barrowing 8 bits from the host side to create further 256 subnets.

3.With Sub -sub network of 10.1.1.0/24 each Sub-sub network will provide 254 hosts.

Sub-netting / VLSM

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1.64/28

1.79/28

1.96/30

1.100/30

1.104/30

1.108/30

1.112/30

1.32/27

1.64/27

1.96/27

1.128/27

1.160/27

1.128/29

1.136/29

1.144/29

EXTERNAL WAN ROUTER 192.168.1.0/24

Sub-netting / VLSM

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Network with no Sub-netting

All hosts think that the other hosts are on the same network

128.143.70.0/16

128.143.137.32/16

subnetmask: 255.255.0.0

128.143.71.21/16


128.143.137.144/16


128.143.71.201/16


IRIS

ET

128.143.0.0/16

128.143.137.32/24


128.143.71.21/24


128.143.137.144/24


128.143.71.201/24


128.143.137.0/24

Subnet

128.143.71.0/24

Subnet

Network with Sub-netting/FLSM & Super-netting

Hosts with same extended network prefix belong to the same network

FLSM

FLSM

Super netting

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Network with Sub-netting/VLSM & Super-netting

Different subnet masks lead to different views of the size of the scope of the network

128.143.0.0/16

128.143.137.32/26

subnetmask: 255.255.255.192

128.143.71.21/24


128.143.137.144/26

subnetmask: 255.255.255.192

128.143.71.201/16


128.143.71.0/24

Subnet128.143.137.128/26

Subnet

128.143.137.0/26

Subnet

VLSM

VLSM

Super netting

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IPv6 Address

IRIS

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IP Address Purpose

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IPv4 Address History

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IPv4 workarounds

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IP address allocation - Hierarchy

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Internet background

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IPv6 - Introduction

IRIS

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Why IPv6 ?

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What’s new from IPv6 ?

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Large address space: IPv6 uses 128-bit addresses, which means that for

each person on the Earth there are 48,000,000,000,000,000,000,000,000,000 addresses!

Enhanced security: IPSec (Internet Protocol Security) is built into IPv6

as part of the protocol . This means that two devices can dynamically create a secure tunnel without user intervention.

IPv6 features

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Header improvements:

The packed header used in IPv6 is simpler than the one

used in IPv4.

The IPv6 header is not protected by a checksum so

routers do not need to calculate a checksum for every

packet.

No need for NAT:

Since every device has a globally unique IPv6 address,

there is no need for NAT.

Stateless address auto configuration:

IPv6 hosts can automatically configure themselves with an IPv6 address.

IPv6 features

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IPv6 utilizes a 128 - bit address.

128 - bit address can provides nearly unlimited supply of address (2128=40,282,366,920,938,463,463,374,607,431,768,211,456)

= 3.4 x 1038)

This provides roughly 50 octillion addresses per person alive on Earth today, or roughly 3.7 x 1021 addresses per square inch of the Earth’s surface

An example of an IPv6 address would be:

1254:1532:26B1:CC14:0123:1111:2222:3333

IPv6 address

IRIS

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Necessity for IPv6 adoption

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Current IPv6 usage on Internet

IRIS

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IPv6 address

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Rules for representing IPv6 address

IRIS

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Omission of zeros

We can drop any leading zeros in each field of an IPv6 address.

For example, consider the following address:

1423:0021:0C13:CC1E:3142:0001:2222:3333

We can condense that address to: 1423:21:C13:CC1E:3142:1:2222:3333

Only leading zeros can be condensed.


IRIS

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If we have an entire field comprised of zeros, we can further compact the following address:

F12F:0000:0000:CC1E:2412:1111:2222:3333 The condensed address would be:

F12F::CC1E:2412:1111:2222:3333 Notice the double colons (::). We can only condense one set

of contiguous zero fields. Thus, if we had the following address:

F12F:0000:0000:CC1E:2412:0000:0000:3333 We could not condense that to:

F12F::CC1E:2412:0000:0000:3333 further F12F::CC1E:2412:0:0:3333


IRIS

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IPv4 utilizes a subnet mask to define the network “prefix” and “host” portions of an address.

This subnet mask can also be represented in Classless network as

Classless Inter-Domain Routing (CIDR) format.

IPv6 always use CIDR notation to determine what bits will represent the prefix of an address: the host bits are fixed.

.

The IPv6 Prefix

IRIS

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Full Address: 1254:1532:26B1:CC14:123:1111:2222:3333/64

Prefix ID: 1254:1532:26B1:CC14:

Host ID: 123:1111:2222:3333

The /64 indicates that the first 64 bits of this address identify the prefix.

The IPv6 Prefix

IRIS

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Understanding Global IPv6 address format

IRIS

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The host portion of an IPv4 address is not based on the hardware address of an interface. IPv4 relies on Address Resolution Protocol (ARP) to map between the logical IP address and the 48-bit hardware MAC address.

IPv6 unicasts generally allocate the first 64 bits of the address to identify the network (prefix), and the last 64 bits to identify the host (referred to as the interface ID). The interface ID is based on the interface’s hardware address.

This interface ID adheres to the IEEE 64-bit Extended Unique Identifier(EUI-64) format. Since most interfaces still use the 48-bit MAC address, the MAC must be converted into the EUI-64 format.

The IPv6 Interface ID and EUI-64 Format

IRIS

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Consider the following MAC address: 1111.2222.3333. The first 24 bits, the Organizationally Unique Identifier (OUI), identify the manufacturer. The last 24 bits uniquely identify the host. To convert this to EUI-64 format: 1. The first 24 bits of the MAC (the OUI), become the first 24 bits

of the EUI-64 formatted interface ID. 2. The seventh bit of the OUI is changed from a “0” to a “1”. 3. The next 16 bits of the interface ID are FFFE. 4. The last 24 bits of the MAC (the host ID), become the last 24

bits of the interface ID. Thus, the MAC address 1111.2222.3333 in EUI-64 format would

become 1311:22FF:FE22:3333, which becomes the interface ID.

The IPv6 Interface ID and EUI-64 Format

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IPv6 has three types of addresses, which can be categorized by type and scope:

Unicast addresses. A packet is delivered to one interface.

Multicast addresses. A packet is delivered to multiple interfaces.

Anycast addresses. A packet is delivered to the nearest of multiple interfaces (in terms of routing distance).

IPv6 does not use broadcast messages.

IPv6 address types

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Unicast and anycast addresses in IPv6 have the following scopes

For multicast addresses, the scope is built into the address structure:

Link-local. The scope is the local link (nodes on the same subnet).

Unique local or Site-local. The scope is the organization (private site addressing).

Global. The scope is global (IPv6 Internet addresses).

IPv6 address types

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IPv6 address types

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Link-Local IPv6 Addresses Link-local IPv6 addresses are used only on a single link

(subnet). Any packet that contains a link-local source or destination

address is never routed to another link. Every IPv6-enabled interface on a host (or router) is assigned a

link-local address. This address can be manually assigned, or auto-configured.

IPv6 (Link-local) address

IRIS

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The first field of a link-local IPv6 address will always begin FE8x (11111110 10).

Link-local addresses are unicasts, and represent 1/1024th of the available IPv6 address space.

A prefix of /10 is used for link-local addresses. FE80::1311:22FF:FE22:3333/10 There is no hierarchy to a link-local address: The first 10 bits are fixed (FE8), known as the Format

Prefix (FP). The next 54 bits are set to 0. The final 64 bits are used as the interface ID

IPv6 Link-local address

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Unique local or Site Local IPv6 Addresses

Site-local IPv6 addresses are the equivalent of “private” IPv4 addresses.

Site-local addresses can be routed within a site or organization, but cannot be globally routed on the Internet.

Multiple private subnets within a “site” are allowed. The first field of a site-local IPv6 address will always begin

FCx (1111110). Site-local addresses are unicasts, and represent 1/128th of

the available IPv6 address space.

IPv6 Unique-local or Site-local address

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Site-local addresses do adhere to a hierarchy: FC00::2731:E2FF:FE96:C283/64 The first 7 bits are the fixed FP (FC). The next 41 bits are set to 0. The next 16 bits are used to identify the private subnet ID. The final 64 bits are used as the interface ID. To identify two separate subnets (1111 and 2222): FEC0::1111:2731:E2FF:FE96:C283/64 FEC0::2222:97A4:E2FF:FE1C:E2D1/64

IPv6 Unique-local or Site-local address

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Aggregate Global IPv6 Addresses Aggregate Global IPv6 addresses are the equivalent of “public”

IPv4 addresses.

Aggregate global addresses can be routed publicly on the Internet.

Any device or site that wishes to traverse the Internet must be uniquely identified with an aggregate global address.

Currently, the first field of an aggregate global IPv6 address will always begin 2xxx (001).

Aggregate global addresses are unicasts, and represent 1/8th of the available IPv6 address space.

IPv6 Aggregate Global IPv6 address

IRIS

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Aggregate global addresses adhere to a very strict hierarchy:

2000::2731:E2FF:FE96:C283/64

The first 3 bits are the fixed FP

The next 13 bits are the top-level aggregation identifier (TLA ID)

The next 8 bits are reserved for future use.

The next 24 bits are the next-level aggregation identifier(NLA ID)

The next 16 bits are the site-level aggregation identifier (SLA ID)

The final 64 bits are used as the interface ID

IPv6 Aggregate Global IPv6 address

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Multicast IPv6 Addresses Multicast IPv6 addresses are the equivalent of IPv4 multicast

addresses. Interfaces can belong to one or more multicast groups.

Interfaces will accept a multicast packet only if they belong to

that group. Multicasting provides a much more efficient mechanism than

broadcasting, which requires that every host on a link accept and process each broadcast packet.

IPv6 Multicast address

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Multicast IPv6 Addresses The first field of a multicast IPv6 address will always

begin FFxx (11111111).

The full multicast range is FF00 through FFFF.

Multicasts represent1/256th of the available IPv6 address space.

FF01:0:0:0:0:0:0:1


IRIS

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Multicast addresses follow a specific format: The first 8 bits identify the address as a multicast (1111 1111)

The next 4 bits are a flag value. If the flag is set to all zeroes (0000),

the multicast address is considered well-known.

The next 4 bits are a scope value: The final 112 bits identify the actual multicast group.

IPv4 multicast addresses had no mechanism to support multiple “scopes.”

IPv6 scopes allow for a multicast hierarchy, a way to contain multicast traffic.


IRIS

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Anycasts There are no broadcast addresses in IPv6. Thus, any IPv6 address that is not a multicast is a unicast

address.

Anycast addresses identify a group of interfaces on multiple hosts.

Thus, multiple hosts are configured with an identical address Packets sent to an anycast address are sent to the nearest

(i.e., least amount of hops) host.

IPv6 Anycast address

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Anycasts Anycasts are indistinguishable from any other IPv6 unicast

address.

Practical applications of anycast addressing are a bit murky One possible application would be a server farm providing

an identical service or function.

Anycast addressing would allow clients to connect to the nearest server

IPv6 Anycast address

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Special (Reserved) IPv6 Addresses The first field of a reserved or special IPv6

address will always begin 00xx. Reserved addresses represent 1/256th of

the available IPv6 address space.

IPv6 Special reserved address

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Various reserved addresses exist, including: 0:0:0:0:0:0:0:0 (or ::) is an unspecified or unknown

address. It is the equivalent of the IPv4 0.0.0.0 address.

It indicates the absence of a configured or assigned address. In routing tables, the unspecified address is used to identify all or any possible hosts or networks.

0:0:0:0:0:0:0:1 (or ::1) is the loopback or local host address.

It is the equivalent of the IPv4 127.0.0.1 address.

IPv6 Special reserved address

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Reserved Addresses - IPv4 and IPv6 Compatibility To alleviate the difficulties of immediately migrating

from IPv4 to IPv6,

specific reserved addresses can be used to embed an IPv4 address into an

Data Communication & Networking IRISET TA-2122.252.230.113/content/ppt/tele/TA_2hl.pdf · Message:...

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