Network Topology

A network topology is the arrangement of a network devices connecting various nodes(sender and receiver) through lines of connection.

There are two ways of defining network geometry:

•  The physical topology
•  The logical topology

The physical topology of a network is the actual geometric layout of workstations. Some  common physical typologies are Bus, Star, Ring, Mash, Tree,  and Hybrid

BUS Topology

 Bus topology is a network type in which every computer and network device is connected to single 

cable. When it has exactly two endpoints, then it is called Linear Bus topology.

Features

Bus topology is used to connect small network.

In bus topology transmission of data is only in one direction and all devices are connected to a single cable.

Advantage of bus topology

It is cost effective.

Cable required is least compared to other network topology.

It is easy to understand.

Easy to expand joining two cables together.

Disadvantage of bus topology

If 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.

It is slower in speed

Ring Topology

In this topology each computer is connected to other in a form of ring. The last Computer is connected to first.

Each computer has two neighbors

. Features

Repeaters are used in ring topology to prevent data loss because the data will have to pass all the connected computer

The transmission is unidirectional

Data is transferred in a sequential bit-by-bit manner. Transmitted data has to pass each node till the desired destination node.

Advantage of Ring topology

Cheap to install and expend network

Transmitted data is not affected by adding more nodes or high traffic because only the nodes having can transmit data

Disadvantage of Ring topology

Failure of one node effect whole network

Adding or removing nodes disturb all network activity

Difficult in troubleshooting

Star Topology

In Star topology all the computer are connected to a central connection point which may be a Hub or Switch.

Device is connected to the hub or switch with UTP Ethernet cable.

Features

Every node has its own connection to central connection device

Can be used with twisted pair, Optical Fibre or coaxial cable.

Advantage of Ring topology

Easy to troubleshoot.

Fast performance with few nodes and low network traffic.

Easy to setup and modify.

Failure of one node did not affect other network

Disadvantage of Ring topology

Installation cost is high

If the Central connection devise fail then all network stop working

Mesh Topology

In Mesh topology all devices is connected to other in a point-to-point connection. If there are n devices in mesh 

topology then each device has n(n-1)/2 connection to link.

There are two technology to transmit data in mesh technology: Flooding & Routing

Flooding  In flooding technique same data is transmitted to all network, no routing logic is required.

Routing  In routing a routing logic is required to connect the nodes as per connection requirement.

Features

Fully connected

Robust

Not Flexible

Advantage of Ring topology

Each connection can carry its own data-load

Provide more security and privacy

Fault can be diagnosed easily

Disadvantage of Ring topology

Installation cost is high

Configuration is difficult

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 joins multiple star typologies together onto a bus and only the hub is directly connected to tree bus and 

each  hub functions as the root of a tree of devices.

Features

Ideal if workstations are located in groups

Used in wide area network

Advantage of Tree topology

Easy management of devices

Expansions of nodes are easy

Extension of star and bus topology

Error detection is easy

Disadvantage of Tree topology

Very Costly

Heavy cabling

Central connection device failed affect whole network.

Maintenance is difficult

Hybrid Topology

Hybrid topology is mixture of different types of topology. If we connect different topology together then it 

will called hybrid topology.

Feature

It is a Mixture of two or more topology

Advantage and disadvantage of the typologies included

Advantage of hybrid topology

Error detection and correction is easy

Effective and flexible

Easy to increase the size of network

Disadvantage of hybrid topology

Costly

Complex design

You can also download these notes from google drive, use following link:

https://drive.google.com/open?id=0B6Ov-Oe4YuYUODZ6a2NZMnJab2c