TOPOLOGIES OF COMPUTER NETWORK

MESH

STAR

TREE

BUS

RING

TOPOLOGY

• DEFINATION

It is the geometric representation of the relationship of all the links & linking devices to each other.

-Two relationship are possible

1.Peer-to-peer

2.Primary-Secondary

Mesh• Every device has a dedicated point to point

link to every other device.

• n(n-1)/2 physical channels to links n devices.

• Every device on network must have n-1 input/output parts.

Diagram

Advantages

• Point to point links make fault.

• Privacy or security.

• Robust one unusable link doesn’t affect entire system.

Disadvantages

• Many cabling & i/o parts are required.

• Installation & reconfiguration are difficult.

• Network required are expensive .

Star• Each device has a dedicated point to point link

only to a central controller called a hub.

• It doesn’t allow direct traffic between devices.

• Controller acts as an exchange.

Diagram

Hub

Advantages

• Star topology is less expensive than mesh topology.

• Easy to install & configure because in star topology each device need only one link & one i/o part.

• This topology is robust.

Disadvantages

• One of the disadvantage of this topology is the dependency of whole topology on one single point the hub.

Tree

• It is a variation of a star.

• Nodes to the tree are linked to central hub that control the traffic to the network.

• Central hub is active hub contains repeats.

• Secondary hubs may be active & passive hub.

Diagram

HUB

HUB HUB HUB

Advantages

• Allows the network the isolation & prioritize communication from different computers.

• Allows more devices to be attached to a single central hub.

Bus• Bus topology is multipoint connection.

• One long cable acts as a backbone to link all the devices in the network.

• Nodes are connected to bus cable by drop lines &taps.

• The drop line is the connection running between the devices & main cable.

Diagram

Drop line Drop line Drop line Drop line

Trap Trap Trap Trap

Advantages

• Easy for installation.

• Less cabling than mesh star or tree topology.

Disadvantages

• Difficult reconnection and fault isolation.

• A fault or break in bus cable stops all transmission.

• Adding a new device may require modification or replacement of backbone.

Ring

• Each device has dedicated point to point line configuration only with two devices on either side of it.

• Each device incorporates a repeater.

• To add or delete a device requires changing only two connection.

Diagram

Advantages

• It is easy for installation.

• Fault isolation is simplified means if one device not receive a signal within a specific period it can issue an alarm it alert the n/w operator to the problem.

Disadvantages

• It has unidirectional traffic.

• Break in a ring can disable entire network.

Thank You

Thank You