Data Communication & networking

This blog is for undergraduate/graduate students who require some basic information about their subjects or any other topic related to data communication.

Monday, 28 March 2011

WAN (Wide Area Network)

Wide Area Network is a computer network that covers a broad area i.e. any network whose communications links cross metropolitan, regional or national boundaries.
For transmission of data beyond local area communication is typically achieved throught a network of intermediate switching nodes. The purpose of switching nodes is to provide a switching facility that will move the data from node to node until it reaches to its destination.

Network Services Available For MAN & WAN:
1- Dialed Circuit Services: There services includes direct dialing and wide area telephone services.
2- DedicatedCircuit Services: It includes voice-grade circuits wideband analog services, T-carrier circuits & synchronous Optical Network (SONET).
3- Circuit Switched Services: it includes Integrated Service Digital Network (ISDN).
4- PacketSwitched Services: It includes X.25, Frame Relay, ATM, SMDS and Ethernet-IP.

Following technologies are used in wide area switched networks,
(1) Circuit Switching (2) Packet Switching (3) Message Switching.
  • Circuit Switching: Requires a dedicated communication path for duration of transmission; wastes bandwidth, but minimizes delays.
  • Message Switching: Entire path is not dedicated, but long delays result from intermediate storage and repetition of message.
  • Packet Switching: Specialized message switching, with very little delay.

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