NETWORK TOPOLOGIES

TOPOLOGY

·        Network topology is the arrangement of the various elements (node,links etc.) of a communication network.

Types of topology

1.      Star topology

2.      Bus topology

3.      Ring topology

4.      Tree topology

5.      Mesh topology

Star topology

·        A star topology is a topology for a Local Area Network (LAN) in which all nodes are individually connected to a central connection point, like a hub or a switch.

Advantages of star topology

·        Easy to add another computer to the network.

·        If one computer on the network fails, the rest of the network continues to function normally

·         Easy to troubleshoot

Disadvantages of star topology

·        The central network device determines the performance and number of nodes the network can handle.

·        If the central computer, hub, or switch fails, the entire network goes down and all computers are disconnected from the network

·        More cables are required to be connected because each computer individually connects to the central server

Bus topology

·        Bus topology uses one main cable to which all nodes are directly connected. The main cable acts as a backbone for the network. One of the computers in the network typically acts as the computer server

Advantages of Bus Topology

·        Cable required is least compared to other network topology.

·        Used in small networks.

·        It is easy to understand.

·        Easy to expand joining two cables together.

Disadvantages of Bus Topology

·        Cables fails then whole network fails.

·        If network traffic is heavy or nodes are more the performance of the network decreases.

·         Cable has a limited length.

Ring topology

·        A ring topology is a Network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node.

Advantages of Ring Topology

·        Token passing makes ring topology perform better than bus topology under heavy traffic

·        No need of server to control connectivity among the nodes

·        Equal access to the resources

Disadvantages of Ring Topology

·        In Unidirectional Ring, a data packet must pass through all the nodes.

·        Adding or deleting the computers disturbs the network activity.

·         Failure of one computer disturbs the whole network.

Tree Topology

It has a root node and all other nodes are connected to it forming a hierarchy. It is also called hierarchical topology.

A tree topology combines characteristics of  bus and star topologies. It consists of groups of star-configured workstations connected to a bus backbone cable.

Advantages of Tree Topology

·        Expansion of nodes is possible and easy.

·        Easily managed and maintained.

• Error detection is easily done.

Disadvantages of Tree Topology

·        Heavily cabled.

·        Costly.

·        If more nodes are added maintenance is difficult.

·        Central hub fails, network fails.

Mesh topology

In mesh topology ,each node is connected to more than one node to provide an alternative root in the case the host is either down or too busy.

Advantages of  Mesh Topology

·        Each connection can carry its own data load.

·        It is robust.

• Fault is diagnosed easily.

Disadvantages of Mesh Topology

·        Installation and configuration is difficult.

·        Cabling cost is more.

• Bulk wiring is required.