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NETWORK TOPOLOGY

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Diagram of different network topologies.

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Introduction

A topology refers to both the physical and

logical layout of a network. The physical

topology of a network refers to the actual layout

of the computer cables and other network

devices.

The logical topology of a network, on the other

hand, refers to the way in which the network

appears to the devices that use it.

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Types

Several topologies are in use for networks

today. Some of the more common include.

Bus topology

Ring topology

Star topology

Mesh topology

Tree topology

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Bus TopologyAll devices are connected to a central

cable, called the bus or backbone.

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Advantages

Compared to other topologies, a bus is

cheap and easy to implement.

Requires less cable than other topologies.

Does not use any specialized network

equipment.

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Disadvantages

There might be network disruption when

computers are added or removed.

Because all systems on the network

connect to a single backbone, a break in

the cable will prevent all systems from

accessing the network.

Difficult to troubleshoot.

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Ring Topology

All devices are connected to one another

in the shape of a closed loop, so that each

device is connected directly to two other

devices, one on either side of it.

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Advantages

Cable faults are easily located, making

troubleshooting easier.

Ring networks are moderately easy to

install.

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Disadvantages

Expansion to the network can cause

network disruption.

A single break in the cable can disrupt the

entire network.

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Star Topology

In the star topology, all computers and other network

devices connect to a central device called a hub or

switch.

Each connected device requires a single cable to be

connected to the hub, creating a point-to-point

connection between the device and the hub.

Using a separate cable to connect to the hub allows the

network to be expanded without disruption to the

network. A break in any single cable will not cause the

entire network to fail.

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Star Topology

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Advantages

Star networks are easily expanded without

disruption to the network.

Cable failure affects only a single user.

Easy to troubleshoot and isolate problems.

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Disadvantages

Requires more cable than most of the

other topologies.

A central connecting device allows for a

single point of failure.

More difficult than other topologies to

implement.

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Mesh Topology

The mesh topology incorporates a unique network

design in which each computer on the network

connects to every other, creating a point-to-point

connection between every device on the network.

The purpose of the mesh design is to provide a

high level of redundancy. If one network cable

fails, the data always has an alternative path to

get to its destination.

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Mesh topology

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Advantages

Provides redundant paths between

devices

The network can be expanded without

disruption to current users.

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Disadvantages

Requires more cable than the other LAN

topologies.

Complicated implementation.

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Tree topology

Tree topologies are comprised of the multiple star

topologies on a bus. Tree topologies integrate

multiple star topologies together onto a bus.

Only the hub devices can connect directly with the

tree bus and each Hub functions as a root of a tree

of the network devices.

This bus/star/hybrid combination supports future

expandability of the computer networks, much

better than a bus or star.

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Tree Topology

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Advantages

It is the best topology for a large computer network for

which a star topology or ring topology are unsuitable due

to the sheer scale of the entire network. Tree topology

divides the whole network into parts that are more easily

manageable.

Tree topology makes it possible to have a point to point

network.

All computers have access to their immediate neighbors in

the network and also the central hub. This kind of network

makes it possible for multiple network devices to be

connected with the central hub.

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Advantage

It overcomes the limitation of star network

topology, which has a limitation of hub

connection points and the broadcast traffic

induced limitation of a bus network

topology.

A tree network provides enough room for

future expansion of a network.

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Disadvantage

Dependence of the entire network on one

central hub is a point of vulnerability for

this topology.

A failure of the central hub or failure of

the main data trunk cable, can cripple the

whole network.

With increase in size beyond a point, the

management becomes difficult.

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The End

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