25-08-2012, 10:12 AM
SEMINAR ON COMPUTER NETWORKS
COMPUTER NETWORKS.ppt (Size: 334.5 KB / Downloads: 44)
INTRODUCTION
Computer network is an interconnected connection of autonomous computers.
Interconnection means that two or more computers are linked together with a medium and data communication devices for the purpose of communicating data and sharing resources.
Local Area Network (LAN)
It is privately owned and links the devices in a single office, building, or campus and is limited to a few kilometers.
Easy physical connection of computers in a LAN.
Addition of new computer to network is easy.
High rate of data transmission is possible.
Peripheral devices like magnetic disk and printer can be shared by the computers in a LAN.
High reliability since failure of one computer in the network does not affect the functioning of other computers.
Metropolitan Area Network (MAN)
A MAN connects a number of LANs into a larger network so that the resources may be shared.
MANs cover much greater distance than LANs do.
MAN can recover very quickly from a link failure.
Wide Area Network (WAN)
A WAN provides long distance transmission of information over large geographic areas that may comprise a country, continent or the whole world.
WAN covers great distance and operate nationwide or even worldwide.
In case of WAN, the cost of data transmission is very high because the transmission medium used are telephone lines or satellite links.
The sped of data transmission is less. It ranges from 1800 to 9600 bits per second (bps).
NETWORK TOPOLOGY
Network topology refers to the way in which network is laid out physically.
Two or more devices connect to a link, two or more links form a topology.
Topology of a network is the geometric representation of the relationship of all links and linking devices to one another.
Mesh Topology
Every device has a dedicated point to point link to every other device. (Dedicated means that the link carries traffic only between the two devices it connects.)
Every device on the network must have n-1 i/o ports.
Advantages of Mesh Topology:-
Dedicated links eliminate traffic problems.
Provides privacy and security.
Failure of any computer does not affect the entire network.
Disadvantages of Mesh Topology:-
Cabling and hardware cost is high.
Installation is difficult.
APPLICATIONS OF COMPUTER NETWORKS
Resource sharing.
Provides high reliability.
Saves money.
Provides a powerful communication medium.
Provides access to remote databases from servers or other computers.
Access to remote information.
Electronic commerce.
CONCLUSION
Computer networks help to share data and programs among various computers with the advancement of data communication facilities.
Computer networks enable the transfer of information between users located at various geographical points.