Thursday 15 December 2011

Topologies (Medium)

Network topologies.

Network topologies are names for how the networks are setup (shape, description etc.)

The basic types of topologies are...

  • Bus.
  • Star
  • Tree
  • Ring
  • Mesh

 Bus.


A bus network can be described as one long network cable that has multiple cables coming off of it to the computers. Terminators are required at the end of the long network cable to stop any signals getting sent back.

Why you should have a Bus network.

It is cost efficient as you only need one cable.
Costs much less than other topologies
No hassle with tangled wires.
Easy to install.
Best suited for small networks.

Why you shouldn’t have a bus network.

If the cable gets damaged or broken the whole network will go down.
All computers on the network will share bandwidth so performance will be slow.
Limited cable length and hard to add new stations.



Star.


A star network is one central switch, hub or computer which all other workstations connect to the central device. This network topology is the most common of all the other networks and is best suited for computers that are scattered around and can’t be connected with an Ethernet cable.


Why you should have a Star network.

Better performance, unlike the Bus network or ring network because data lines aren’t being shared with other work stations.
Easy to install
No interruptions to the network if stations are added or taken away.



Why you shouldn’t have a Star network

If the central device fails the network will go down.
If one workstation is using up most of the central devices processing capacity.
Network size is limited to amount of workstations that can connect to the central device.
Performance of the network depends on the capabilities of the central device.


Tree.


 A tree network is made when two or more star networks are connected.
If one star network (the central hub) goes down all the computers in that star network will be effected but the other star networks will not. It connects the different star networks together by a wire exactly like the bus network does to connect all the different work stations/nodes.


Why you should have a tree network.

Easy to add and remove stations
 You can add whole star networks at one time to the network.
Perfect for schools, universities and colleges.


Why you shouldn’t have a tree network.

A lot of cable is required.
The network can get really big and be hard to manage.
The length of the network depends on the length of the cable.


Ring.


A ring network is a circle of computers that are all connected by one cable. Kind of like a bus network but the cable loops. In a ring network the data flows in all of the same direction, so there is no risk of packet collision.

Why you should have a ring network.

It’s faster than other network topologies because the data flows in one way.
Cheap and easy to expand.



Why you shouldn’t have a ring network.

If the ring is broken then the whole network will go down.
If extra workstations are added the network will slow down with more users.
Network adapter cards are more expensive than Ethernet cards or hubs.

Mesh.


Mesh networking is where workstations are used as independent router. This is so the data can get transferred to the target location in the fastest way possible. If one connection is blocked either by being offline or having a cable damaged the network will allow data too “hop” to another workstation to find the next quickest route. It can be called a self healing network because it will find a connection if the one it is using breaks down.

Why you should get a mesh network.

Self healing
Not dependent on a single switch or hub
Perfect for lots of workstations
If one connection fails the whole network does not go down.
No traffic problems
If one connection should fail it is easy to see where the failure happened as all nodes are connected to each other.


Why you shouldn’t have a mesh network.

A lot of cable is required to connect all the nodes together.
Can be difficult when trying to connect all nodes together.
Much more expensive than any of the other networks.

















All network topologies have their advantages and disadvantages. They are all used in businesses, some more than others but it ultimately depends on what you want the network to do. I you want the network to be stable, a mesh network would be the most reliable or if you want a home network, then the star network is efficient.

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