Network Topolog
-
Upload
sammy17 -
Category
Technology
-
view
112 -
download
1
description
Transcript of Network Topolog
![Page 1: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/1.jpg)
Network Topologies
![Page 2: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/2.jpg)
04/10/23 2
Objectives
• Describe the basic and hybrid LAN physical topologies, their uses, advantages, and disadvantages
• Describe a variety of enterprise-wide and WAN physical topologies, their uses, advantages, and disadvantages
• Compare the different types of switching used in data transmission
• Understand the transmission methods, or logical topologies, underlying Ethernet, Token Ring, LocalTalk, and FDDI networks
![Page 3: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/3.jpg)
04/10/23 3
Simple Physical Topologies
• Physical topology– Physical layout of a network
• A Bus topology consists of a single cable—called a bus— connecting all nodes on a network without intervening connectivity devices
![Page 4: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/4.jpg)
04/10/23 4
Advantages of Bus Topology
• Works well for small networks
• Relatively inexpensive to implement
• Easy to add to it
![Page 5: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/5.jpg)
04/10/23 5
Disadvantages ofBus Topology
• Management costs can be high
• Potential for congestion with network traffic
![Page 6: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/6.jpg)
04/10/23 6
Simple Physical Topologies
• Ring topology– Each node is connected to the two nearest nodes so the entire
network forms a circle– One method for passing data on ring networks is token passing
• Active topology– Each workstation transmits data
![Page 7: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/7.jpg)
04/10/23 7
Advantages of Ring Topology
• Easier to manage; easier to locate a defective node or cable problem
• Well-suited for transmitting signals over long distances on a LAN
• Handles high-volume network traffic
• Enables reliable communication
![Page 8: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/8.jpg)
04/10/23 8
Disadvantages ofRing Topology
• Expensive
• Requires more cable and network equipment at the start
• Not used as widely as bus topology– Fewer equipment options– Fewer options for expansion to high-speed
communication
![Page 9: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/9.jpg)
04/10/23 9
Simple Physical Topologies
• Star topology– Every node on the network is connected through
a central device
![Page 10: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/10.jpg)
04/10/23 10
Advantages of Star Topology
• Good option for modern networks
• Low startup costs
• Easy to manage
• Offers opportunities for expansion
• Most popular topology in use; wide variety of equipment available
![Page 11: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/11.jpg)
04/10/23 11
Disadvantages ofStar Topology
• Hub is a single point of failure
• Requires more cable than the bus
![Page 12: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/12.jpg)
04/10/23 12
Hybrid Physical Topologies
• Hybrid topology– Complex combination of the simple physical topologies
• Star-wired ring– Star-wired topologies use physical layout of a star in
conjunction with token ring-passing data transmission method
![Page 13: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/13.jpg)
04/10/23 13
Hybrid Physical Topologies
• Star-wired bus– In a star-wired bus topology, groups of workstations are
star-connected to hubs and then networked via a single bus
![Page 14: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/14.jpg)
04/10/23 14
Hybrid Physical Topologies
• Daisy-Chained– A Daisy chain is linked series of devices
![Page 15: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/15.jpg)
04/10/23 15
Hybrid Physical Topologies
• Hierarchical hybrid topology– Uses layers to separate devices by priority or function
![Page 16: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/16.jpg)
04/10/23 16
Enterprise-Wide Topologies
• Enterprise– An entire organization
• Backbone networks– Serial backbone– Distributed backbone– Collapsed backbone– Parallel backbone
![Page 17: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/17.jpg)
04/10/23 17
Enterprise-Wide Topologies
• Serial backbone– Two or more hubs connected to each other by a single cable
• Distributed backbone– Hubs connected to a series of central hubs or routers in a hierarchy
![Page 18: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/18.jpg)
04/10/23 18
Enterprise-Wide Topologies
• Collapsed backbone– Uses a router or switch as the single central
connection point for multiple subnetworks
![Page 19: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/19.jpg)
04/10/23 19
Enterprise-Wide Topologies
• Parallel Backbone– Collapsed backbone arrangement that consists of more than one
connection from central router or switch to each network segment
![Page 20: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/20.jpg)
04/10/23 20
Enterprise-Wide Topologies
• Mesh networks– Routers are interconnected with other routers, with at least two
pathways connecting each router
![Page 21: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/21.jpg)
04/10/23 21
Wide Area Network (WAN) Topologies
• Peer-to-peer topology– WAN with single interconnection points for each location– Dedicated circuits
• Continuous physical or logical connections between two access points that are leased from a communication provider
![Page 22: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/22.jpg)
04/10/23 22
Wide Area Network (WAN) Topologies
• Ring WAN topology– Each site is connected to two other sites so that entire
WAN forms a ring pattern
![Page 23: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/23.jpg)
04/10/23 23
Wide Area Network (WAN) Topologies
• Star WAN topology– Single site acts as the central connection point for several
other points
![Page 24: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/24.jpg)
04/10/23 24
Wide Area Network (WAN) Topologies
• Mesh WAN topology– Many directly interconnected locations forming a complex mesh
![Page 25: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/25.jpg)
04/10/23 25
Logical Topologies
• Refers to the way in which data are transmitted between nodes
• Describes the way:– Data are packaged in frames
– Electrical pulses are sent over network’s physical media
• Logical topology may also be called network transport system
![Page 26: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/26.jpg)
04/10/23 26
Switching
• Component of network’s logical topology that determines how connections are created between nodes– Circuit switching
• Connection is established between two network nodes before they begin transmitting data
– Message switching• Establishes connection between two devices, transfers
information to second device, and then breaks connection
– Packet switching• Breaks data into packets before they are transmitted
![Page 27: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/27.jpg)
04/10/23 27
Ethernet
• Carrier Sense Multiple Access with Collision Detection (CSMA/CD)– The access method used in Ethernet
– Collision• In Ethernet networks, the interference of one network node’s
data transmission with another network node’s data transmission
– Jamming• Part of CSMA/CD in which, upon detection of collision,
station issues special 32-bit sequence to indicate to all nodes on Ethernet segment that its previously transmitted frame has suffered a collision and should be considered faulty
![Page 28: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/28.jpg)
04/10/23 28
Ethernet
CSMA/CD process
![Page 29: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/29.jpg)
04/10/23 29
Ethernet
• On an Ethernet network, an individual network segment is known as a collision domain– Portion of network in which collisions will occur if
two nodes transmit data at same time
• Data propagation delay– Length of time data take to travel from one point
on the segment to another point
![Page 30: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/30.jpg)
04/10/23 30
Ethernet
• Demand priority– Method for data transmission used by 100BaseVG Ethernet networks– Demand priority requires an intelligent hub
CSMA/CD versus demand priority
![Page 31: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/31.jpg)
04/10/23 31
Ethernet
• Traditional Ethernet LANs, called shared Ethernet, supply fixed amount of bandwidth that must be shared by all devices on a segment
• Switch– Device that can separate network segments into
smaller segments, with each segment being independent of the others and supporting its own traffic
• Switched Ethernet– Newer Ethernet model that enables multiple nodes to
simultaneously transmit and receive data over logical network segments
![Page 32: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/32.jpg)
04/10/23 32
Ethernet
A switched Ethernet network
![Page 33: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/33.jpg)
04/10/23 33
Ethernet
• Gigabit Ethernet– 1 Gigabit Ethernet
• Ethernet standard for networks that achieve 1-Gbps maximum throughput
– 10 Gigabit Ethernet• Standard currently being defined by IEEE 802.3ae
committee• Will allow 10-Gbps throughput• Will include full-duplexing and multimode fiber
requirements
![Page 34: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/34.jpg)
04/10/23 34
Ethernet
• Padding– Bytes added to data portion of an Ethernet frame to
make sure this field is at least 46 bytes in size
• Ethernet frame types:– IEEE 802.3 (“Ethernet 802.2” or “LLC”)– Novell proprietary 802.3 frame (or “Ethernet 802.3”)– Ethernet II frame– IEEE 802.3 SNAP frame
![Page 35: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/35.jpg)
04/10/23 35
IEEE 802.3 (“Ethernet 802.2” or “LLC”)
• Default frame type for versions 4.x and higher of Novell NetWare network operating system– Sometimes called LLC frame– In Novell’s lexicon, this frame is called Ethernet 802.2 frame
An IEEE 802.3 frame
![Page 36: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/36.jpg)
04/10/23 36
IEEE 802.3 (“Ethernet 802.2” or “LLC”)
• Service Access Point (SAP)– Identifies node or internal process that uses LLC
protocol
• Frame Check Sequence (FCS)– This field ensures that data are received just as
they were sent
• Cyclical Redundancy Check (CRC)– Algorithm used by FCS field in Ethernet frames
![Page 37: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/37.jpg)
04/10/23 37
Novell Proprietary 802.3 (or “Ethernet 802.3”)
• Original NetWare frame type• Also called:
– 802.3 Raw– Ethernet 802.3 frame
A Novell proprietary 802.3 frame
![Page 38: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/38.jpg)
04/10/23 38
Ethernet II
• Original Ethernet frame type developed by DEC, Intel and Xerox, before IEEE began to standardize Ethernet
An Ethernet II frame
![Page 39: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/39.jpg)
04/10/23 39
IEEE 802.3 SNAP
• Adaptation of IEEE 802.3 and Ethernet II• SNAP stands for Sub-Network Access Protocol
An IEEE 802.3 SNAP frame
![Page 40: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/40.jpg)
04/10/23 40
Understanding Frame Types
• Learning about networks is analogous to learning a foreign language, with the frame type being the language’s syntax– Just as you may know the Japanese word for go but
how to use it in a sentence, you may know all about the IPX/SPX protocol but not how devices handle it
• Autosense– Feature of modern NICs that enables a NIC to
automatically sense what types of frames are running on a network and set itself to that specification
![Page 41: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/41.jpg)
04/10/23 41
Design Considerations for Ethernet Networks
• Cabling
• Connectivity devices
• Number of stations
• Speed
• Scalability
• Topology
![Page 42: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/42.jpg)
04/10/23 42
LocalTalk
• Logical topology designed by Apple Computer, Inc.
• Uses a transmission method called Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA)
• A teleconnector is a transceiver used on a LocalTalk network
• Macintosh version of TCP/IP is called MacTCP
![Page 43: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/43.jpg)
04/10/23 43
Token Ring
• Token Ring networks use the token passing routine and a star-ring hybrid physical topology
• The 100-Mbps Token Ring standard is known as High-Speed Token Ring (HSTR)
• On a Token Ring network, one workstation, called the active monitor, acts as the controller for token passing
![Page 44: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/44.jpg)
04/10/23 44
Token Ring
• Multistation Access Unit (MAU)– Regenerates signals
Interconnected Token Ring MAUs
![Page 45: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/45.jpg)
04/10/23 45
Token Ring
• Control Access Unit (CAU)– Connectivity device used on a Token Ring
network
• Lobe Attachment Module (LAM)– Device that attaches to a CAU to expand the
capacity of that device
![Page 46: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/46.jpg)
04/10/23 46
Token Ring
• Token Ring networks with STP cabling may use a type 1 IBM connector
• A DB-9 connector is another type of connector found on STP Token Ring networks
Type 1 IBM and DB-9 Token Ring connectors
![Page 47: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/47.jpg)
04/10/23 47
Token Ring
• Media filter– Device that enables two types of cables or connectors to be linked
• Token Ring media filter– Enables DB-9 cable and type 1 IBM cable to be connected
A Token Ring media filter
![Page 48: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/48.jpg)
04/10/23 48
Token Ring
• Token Ring switching– Like Ethernet networks, Token Ring networks can take
advantage of switching to better utilize limited bandwidth
• Token Ring frames– IEEE 802.5 Token Ring frame– IBM Token Ring frame
An IBM Token Ring frame
![Page 49: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/49.jpg)
04/10/23 49
Design Considerations for Token Ring Networks
• Cabling
• Connectivity devices
• Number of stations
• Speed
• Scalability
• Topology
![Page 50: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/50.jpg)
04/10/23 50
Fiber Distributed Data Interface (FDDI)
• Logical topology whose standard was originally specified by ANSI in mid-1980s and later refined by ISO
![Page 51: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/51.jpg)
04/10/23 51
Asynchronous Transfer Mode (ATM)
• Logical topology that relies on a fixed packet size to achieve data transfer rates up to 9953 Mbps
• The fixed packet in ATM is called a cell• A unique aspect of ATM technology is that it
relies on virtual circuits
![Page 52: Network Topolog](https://reader030.fdocuments.us/reader030/viewer/2022020122/54c8ac374a79594b1c8b4574/html5/thumbnails/52.jpg)
04/10/23 52
Asynchronous Transfer Mode (ATM)
• ATM uses circuit switching, which allows ATM to guarantee a specific quality of service (QOS)
• ATM technology can be integrated with Ethernet or Token Ring networks through the use of LAN Emulation (LANE)