Computer Networks & Topologies

Group Members

Shahid Ahmed Sp11-Bba-100Shahzad Zeb Sp11-Bba-084Nadia Naseer Abbasi Sp11-Bba-079Ahsan Bashir Sp11-Bba-007Nosherwan Zafar Sp11-Bba-080Muhammad Fahad Sp11-Bba-082

Computer Network

A way of connecting computers together so that they can communicate, share information and other resources with each other is called computer network.A computer network is also called the information network.

Types of Computer Networks

LAN

WAN

MAN

LAN

LAN• LAN stands for Local Area Network• It is used to cover a small area• The network of computers in a computer lab of a

college and network of computers in an office building are examples of LAN

• In a LAN, the nodes are connected via cables• A LAN may use star topology, ring topology or bus

topology• A LAN covers small distance such as one office or

building

WAN

WAN• WAN stands for wide area network• It is used to cover a large or vide area• The computers connected to WAN can be in

different cities or countries• Nodes are connected through telephone lines

however they can be connected through microwave or satellite systems

• Typically a WAN consists of two or more LANs connected together

• The internet is world’s largest WAN

MAN

MAN• MAN stands for metropolitan area network• It covers area of a single city• Usually MAN connects more than one LANs in a

city or town• It covers smaller geographical area than WAN• Fibre optic cables are used as communication

media• So it is very high-speed network• Mobile phones (cellular) system often use MAN

Network Topology

There are many ways in which computers can be connected together in computer network.

The way in which computers or other devices are connected in network is called network topology.

Types of network Topology

Bus topology

Star topology

Ring topology

Tree topology

Mesh topology

Bus topology

Bus topology• All nodes or devices are connected to a

common communication medium or central single cable that is backbone cable

• This cable is called Bus • It is very simple network and less expensive• But it supports only a small number of nodes• It does not need much cabling to connect

nodes as compared to other networks

Star topology

Star topology• Each node is directly connected to a central

connection point known as Hub• nodes are connected to the Hub with unshielded

twisted pair Ethernet• Star topology is most commonly used in LAN• Many home networks uses the Star topology• This network forms a shape like star • It is easy to install and to maintain• It requires more cabling than Bus topology

Ring topology

Ring topology

• In a ring topology, each node is connected to two adjacent nodes or neighbours

• It forms a closed ring or loop• In this way the last node connects to the first

node to complete the ring• All the messages travel through a ring in one

direction (clockwise or anti-clockwise)• Token passing method is used in this topology• It is less expensive than star topology

Tree topology

Tree topology• Nodes are connected to each other in such a way that

it forms a tree like structure • Multiple star topologies are used to form a tree

network• It has combined features of bus and star topology• One central hub and multiple secondary hubs are

used • The cable TV network is an example of tree network• Main cable is divided into branches and each branch

is further divided in to smallest branches and so on

Mesh topology

Mesh topology

• Each node is directly connected to every other node on the network

• This type of network involves concept of routes• Some WANs like internet uses Mesh topology• Each node can send message to its destination

through multiple paths• Its performance is not affected with heavy load

of data transmission• It is difficult to install and is much expensive