Network Topologies

The common topologies are Bus, Tree, Ring, and Star.

1. Bus topology : Bus are characterized by the use of a multi-point medium. In Bus, all stations attach through hardware interfacing known as Tap directly to a linear transmission medium or bus.

Full duplex operation between the station and the tap allows the data to be transmitted onto the bus and received from bus .

Advantage is that Low installation cost and Disadvantage is that If cable break-down all the network will be down .

2. Tree topology: The tree topology is a generalization of Bus topology . The Tree layout begins at a point known as the Headend, where one or more cables start and each of these may have branches.

Advantage is that faster data rate and Disadvantage is that High Installation rate.

3. Ring topology : The network consist of a set of repeaters joined by point-to-point. The repeater is a device of receiving data on one link and transmitting them, bit by bit on other link as fast as they are received.

The links are unidirectional i.e. data are transmitted in one direction only. Data circulates around the ring in one direction .

Advantage is that Low communication cost and Disadvantage is that If Ring is break-up then whole Ring is Divided into two parts .

4. Star topology : In Star topology, each station is directly connected to a central node, referred to as the star coupler, via two point-to-point links, one for transmission in each direction .

The central node to act as a frame switching device. An incoming frame is buffered in the node and then retransmited on an outgoing link to the destination station.

Advantage is that No installation cost with unshielded twisted pair and Disadvantage is that If two devices transmit it the same time, there will be a collision.