Network Topology
 Logical layout of wires and equipment
 Choice affects
Network performance
 Network size
 Network collision detection

BUS
 Also called linear bus
 One wire connects all nodes
 Terminator ends the wires
 Advantages
 Easy to setup
 Small amount of wire
 Disadvantages
 Slow
 Easy to crash
STAR
 All nodes connect to a hub
 Packets sent to hub
 Hub sends packet to destination
 Advantages
 Easy to setup
 One cable can not crash network
 Disadvantages
 One hub crashing downs entire network
 Uses lots of cable
 Most common topology
Token Ring Network
 Originally developed by IBM in 1970’s Still IBM’s primary
LAN technology
 In cases of heavy traffic, the token ring network has higher
throughput than ethernet due to the deterministic (nonrandom) nature of the medium access
 Nodes connected in a circle
 Tokens used to transmit data
 Nodes must wait for token to send
 Is a robust network i.e. it is fault tolerant through fault
management mechanisms
 Can support data rates of around 16 Mbps
 Typically uses twisted pair
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 Advantages
 Time to send data is known
 No data collisions
 Disadvantages
 Slow
 Lots of cable
• Token Ring Topology
• Every computer serves as
a repeater to boost signals
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• Typical way to send data:
• Token passing
• only the computer who
gets the token can send
data
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• Disadvantages
• Difficult to add computers
• More expensive
• If one computer fails, whole network fails
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FDDI (Fiber Distributed Data Interface)
 FDDI is a standard developed by the
American National Standards
Institute (ANSI) for transmitting data
on optical fibers

 Supports transmission rates of up to
200 Mbps
 Supports up to 1000 nodes
 Has a range of up to 200 km
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MESH

All computers connected together

Internet is a mesh network

Advantage
 Data will always be delivered

Disadvantages
 Lots of cable
 Hard to setup
 To identify
 No of Llinks = n(n-1)/2
 No of Ports
= n -1