Computer network topology is the way various components of a network (like nodes, links, peripherals, etc) are arranged. Network topologies define the layout, virtual shape or structure of network, not only physically but also logically. The way in which different systems and nodes are connected and communicate with each other is determined by topology of the network. Topology can be physical or logical. Physical Topology is the physical layout of nodes, workstations and cables in the network; while logical topology is the way information flows between different components.
In general, physical topology relates to a core network whereas logical topology relates to basic network.
Types of Physical Network Topologies:
1. Bus Topology
2. Star Topology
3. Ring Topology
4. Mesh Topology
5. Tree Topology
(i) Bus Topology:
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.
(ii) Star Topology:
Advantages:
- As compared to Bus topology it gives far much better performance, signals don’t necessarily get transmitted to all the workstations. 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.
- Centralized management. It helps in monitoring the network.
- Failure of one node or link doesn’t affect the rest of network. At the same time its easy to detect the failure and troubleshoot it.
(iii) Ring Topology:
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.
- There is no need for network server to control the connectivity between workstations.
- Additional components do not affect the performance of network.
- each computer has equal access to resources.
(iv) Mesh Topology:
Advantages:
- Data can be transmitted from different devices simultaneously. This topology can withstand high traffic.
- Even if one of the components fails there is always an alternative present. So data transfer doesn’t get affected.
- Expansion and modification in topology can be done without disrupting other nodes.
(v) Tree Topology:
Advantages:
- It is an extension of Star and bus Topologies, so in networks where these topologies can’t be implemented individually for reasons related to scalability, tree topology is the best alternative.
- Expansion of Network is possible and easy.
- Here, we divide the whole network into segments (star networks), which can be easily managed and maintained.
- Error detection and correction is easy.
- Each segment is provided with dedicated point-to-point wiring to the central hub.
- If one segment is damaged, other segments are not affected.
