(1) Topology is the geometric Network of the Computer in a Network.

(2) Network Topology define how various computers or nodes are connected to one another.

(3) Topology defines the physical / logical arrangement of link in a Network.

(4) Topology refers to the way in which endpoints or station / terminals attached to the network are interconnected.

Topologies are classified as :-

I. Mesh Topology

(1) Mesh Topology is also called complete Topology.

(2) Every Device has a dedicated point to point link to other device.

(3) Mesh Topology designed for long distance data transmission between nodes.

4) Numbers of links/cables for full connected mesh of N nodes – N(N-1)/2

(5) Numbers of ports = N – 1

Advantages

(1) No traffic problem

(2) Better Security

(3) Robust

Disadvantages

(1) Hardware required to connect each link can be expensive.

(2) Installation and Reconnections are difficult.

(3) Each devices should be connected with other.

II. Star Topology

Star Topology uses twisted pair cable (10 base T to 100 base T) cabling and requires all devices are connect to a hub

If one link fails their is no alternate to connect the rest of Network.

Advantages

(1) Ease of used.

(2) Reconfiguration of Network is easy.

(3) Useful when centralised control is required.

(4) Centralised control problem diagonsed.

(5) Add and Remove a computer without distrubing other computer

(6) Fault identification is easy.

(7) If any node fails doesn’t affect.

Disadvantages

(1) Each devices require its own cable segment.

(2) Centralized is expensive.

(3) Installation and Configuration is difficult.

III. Ring Topology

(1) Ring Topology is also called as circular Topology.

(2) Each devices are connected as a dedicated and point-to-point.

(3) Line configuration only takes place when the two device are connected to each other / on either side.

(4) A signal is passed along the ring one direction from device to device until it reaches to its destination.

(5) Each devices in the ring in corporates as a Repeater.

(6) when devices receives a signal intended for another devices,its repeated

(7) Regenerates the bits and pass them along.

(8) Ring operates communication Network, if it perform following function.

(a) Data Insert

(b) Data Delete

(c) Data Reception

Advantages

(1) Insertion and deletion is easy with the help of ring.

(3) Link Failure can be easily found as devices is immediate connected to Neighbour.

Disadvantages

(1) Failure of one node on the ring can affect the entire Network.

(2) Adding and removing node disrupts the network.

(3) Maximum ring length of device is limited.

IV. BUS Topology

(1) Bus Topology is also known as Linear Topology.

(2) All topology like Mesh, Star, Ring are decdicated a single (point-to-point) configuration.

(3) Bus topology acts as Multipoint, because one cable acts as a backbone to link all other devices in a network.

(4) The Speed of bus topology is slow because one computer can send a message at a time. A computer must wait until the bus is free before it can transmit.

(5) Dropline give connection between devices and main cable.

(6) A tap is a connection that punctures with metallic core.

(7) It require both cable end for start and closed terminal.

Advantage

(1) Early to Extend.

(2) Short cable.