Network Topolgies

By Louise Haigh

The bus network

This is the bus network it looks a little confusing but its not really.


In this type of topology, all the nodes are connected to the single cable , by the help of interface connectors. This central cable is the backbone of the network and is known as Bus . Every workstation communicates with the other device through this Bus.


Advantages


It is easy to set-up and extend bus network.
Cable length required for this topology is the least compared to other networks.

Bus topology costs very less.
Linear Bus network is mostly used in small networks. Good for LAN.


Disadvantages


There is a limit on central cable length and number of nodes that can be connected.
Dependency on central cable in this topology has its disadvantages. If the main cable encounters some problem, whole network breaks down.
Proper termination is required to dump signals. Use of terminators is must.

The ring network

This is the ring network it just goes around and around and around


In Ring Topology, all the nodes are connected to each-other in such a way that they make a closed loop. Each workstation is connected to two other components on either side, and it communicates with these two adjacent neighbours. Data travels around the network, in one direction. Sending and receiving of data takes place by the help of token.


Advantages


This type of network topology is very organized. Each node gets to send the data when it receives an empty token. This helps to reduces chances of collision. Also in ring topology all the traffic flows in only one direction at very high speed. Even when the load on the network increases, its performance is better than that of Bus topology


Disadvantages


Each packet of data must pass through all the computers between source and destination. This makes it slower than Star topology
If one workstation or port goes down, the entire network gets affected. Network is highly dependent on the wire which connects different components.

The Star Network

This is the Star Network it just goes up and down.


In Star topology, all the components of network are connected to the central device called “hub” which may be a hub, a router or a switch. Unlike Bus topology where nodes were connected to central cable, here all the workstations are connected to central device with a point-to-point connection. So it can be said that every computer is indirectly connected to every other node by the help of “hub”.


Advantages


As compared to Bus topology it gives far much better performance, signals don’t necessarily get transmitted to all the workstations. A sent signal reaches the intended destination after passing through no more than 3-4 devices and 2-3 links. Performance of the network is dependent on the capacity of central hub. Easy to connect new nodes or devices. In star topology new nodes can be added easily without affecting rest of the network. Similarly components can also be removed easily.


Disadvantages


Too much dependency on central device has its own drawbacks. If it fails whole network goes down. The use of hub, a router or a switch as central device increases the overall cost of the network. Performance and as well number of nodes which can be added in such topology is depended on capacity of central device.