Sunday, 28 August 2016

Frame Relay

Frame Relay
         Frame relay is packet - switching telecommunication service designed for cost efficient data transmission for internet traffic between local area network and between endpoints in wide area network. This service is widely available and implemented, is in the process of being discontinued by major internet service providers.
        In frame relay environment data is travel source to destination in a virtual link safety, If multiple endpoint (destination) is available than we are assign DLCI (data link connection Identifier) number on each virtual link for identification. This circuit is also known as permanent virtual circuit(PVC).

  There are two endpoint BO1 and BO2 and each of them has same HQ.



If we are arrange all of them in Frame relay cloud than scenario is :



There, Red virtual circuit is between HQ and BO1 and blue is between HQ and BO2.

      There is no virtual circuit between BO1 and BO2, so we can not forward traffic between them.
      Each and every VC is payable, that know CIR (committed Information Rate). The main benefit  of frame relay is that when no other customers are using the frame relay network it's possible we get a higher speed than what we paid for the CIR however is a speed that is guaranteed.

  How to know  if PVC is working or not?

  Frame relay is use something called LMI stand for Local management Interface.

   

LMI has two function:
    1. keepalive
    2. PVC status (active or not)
    3. DLCI

LMI has 3 types:
    1. Cisco
    2. ANSI T1.617 Annex D
    3. ITU-T Q.933 Annex A

  WAN protocol describe the physical layer and data link layer. Frame relay use on the data link layer. it's donn't use MAC address since that's Ethernet but we do have something else called a DLCI number and its use iarp (inverse address resolution protocol) for conversation.

  Frame-relay supports multiple topologies:
    1. Full - mesh
    2. partial - mesh
    3. Hub and Spoke

 Continue read Frame relay - part 2 post....