Computer NetworksTo : Sir Ahsan Shah

Group MembersI. Raja Zeeshan.II. Parvez Ahmed Butt.III. Faizan Butt.IV. Zohaib Qureshi.V. Khavar maqsood.VI. Mariyam Tariq.VII. Irfan liaqat.VIII.Munir akhoon.

University of Azad Jammu & Kashmir

What is Computer?Computer is a machine which consists of various hardware parts and different software to process the store data in a memory.

Computer NetworksA computer network is a system in which computers are connected to share information and resources.

Kinds of Computer NetworksComputer Networks Classify in different way:o Based on transmission Medium:i. Wiredii. Wirelesso Based on topology:i. Bus, Star, Ring…o Based on network size:i. LAN,MAN and WANo Based on management method:i. Peer-to-peer and Client/server

Based on transmission mediumWired Media

Based on transmission mediumWireless Media

Based on transmission mediumWire pair• Made by copper insulated by PVC.• Commonly used in telephone line .• Transmission speed is 1200bits/s.Advantages• Un expensive • Easy to used and install.Disadvantages • Easily pickup noise signal which produce high

error rate.

Based on transmission mediumCoaxial cables• Made of copper insulated by PVC and copper

mesh.• Transmission speed is 10mb/s.• Extensive used in telephone line and CCTV.• Transmit 15000 voice calls at same time.• Offers cleaner and crisper data transmission with

low error.

Based on transmission mediumOptical fiber• It is thin like human hair made by glass.• Transmit 50,000 voice calls same time.• Transmit data in form of light • Provided high quality transmission of signal.• Data transmission speed is 1gega/s• Used to communicate analog and digital signal.

Topology• TopologyNetwork consist of two or more computer that are linked in order to share resource, exchange file and allow electronic communication.

Based on topology• Types of Topology:

Tree Topology Mesh Topology

Ring Topology

Star Topology

Based on topology Bus topology.• A bus network is an arrangement in a local area network (LAN) in which each node (workstation or other device) is connected to a main cable or link called the bus.• A bus network is simple and reliable. If one node fails to operate, all the rest can still communicate with each other. 

Based on topology

Bus topology. Advantages.• Easy to connect.• Require less cable length than a star topology. Disadvantages• Speed is slow.• Depend on central wire.• More than one system cannot operate at same time.

Based on topology

Star topology.A star network is a local area network (LAN) in which all nodes (workstations or other devices) are directly connected to a common central computer.

Based on topology Star topology.• In star topology switch and hub both are used.• Number of port in hub is less than switch. Disadvantages• If central device (hub or switch) fail or stop working

properly than network does not work..

Based on topology Ring topology.• A ring topology in a local area network (LAN) in

which the nodes (workstations or other devices) are connected in a closed loop configuration

Based on topologyRing topology.Advantages • Each computer has equal access to resources.• Even when the load on the network increases, its

performance is better than that of Bus topology.

Disadvantages • Messages will pass in clock wise or anti clock

wise … but if any one system fail than the message will not pass and the network stop working ..

Based on topology Mesh topology.• A mesh topology is the type of topology in which

every one node is directly connect to other.

Based on topologyMesh topology. Advantages• High speed.• High security.

Disadvantages • And it is difficult to handle too much wire.

Based on topologyTree topology.Tree topology integrates the characteristics of Star and Bus topology.Advantages • Error detection and correction is easy.• If one segment is damaged, other segments are

not affected.

Based on topologyTree topology.

Disadvantages • As more and more nodes and segments are added,

the maintenance becomes difficult.

Based on Network Size

• Network Size There are three types of Network size.I. LANII. MANIII. WAN

Based on Network SizeLocal Area Network (LAN)

A Computer Network that interconnects computers within a limited area i.e. office, home, laboratory.• Used by organization • Transmission speed is 100-1000mbps.• Fast speed due to limited distance.

Based on Network Size

Metropolitan Area Network (MAN)• Combination of two LAN.• Organization have multiple branches used this

network.• Slow speed due to large distance.

Based on Network SizeWide Area Network (WAN):• Combination of thousand of LAN and MAN.• Transmission speed is much faster.• It can accommodate billion of used at same time. e.g internet

Based on Management Method

There are two type of Management.

• Client-server model.

• Peer to peer model.

Based on Management Method

• Client-server model.In the client server model. Two processes are involved, one on the client side and one on the server side. First the client sends a message over the network to the server, the client then waits for a reply. When the server receives the request it performs the requested work and send back a reply.

Based on Management Method

• Client-server model.

Based on Management Method

• Peer to Peer model. In the peer to peer architecture individuals form a loose group and can communicate with other in the group. There is no need to distinguish client and servers in this architecture.

Uses of Computer Networks

Facilitating Communication

Sharing Hardware:

Sharing Files, Data & Info :

Sharing Software's:

Future of Computer Networks

In future Networks will be completely different from present networks.• We are expecting even house hold appliances like electric bulb and toaster to be a part of network. • They will have their own IP Addresses to make them accessible & Controlled by Network.

Future of Computer Networks• Bluetooth will replace every wire that we use. • Its primary purpose was to replace USB but in future we are expecting to connect our TV to DVD Player by Bluetooth or even speaker to radio.

Future of Computer Networks• Bluetooth will replace every wire that we use. • Its primary purpose was to replace USB but in future we are expecting to connect our TV to DVD Player by Bluetooth or even speaker to radio.