DLCI or Data Link Connection Identifier is a unique number assigned by a Frame Relay service provider that helps the network to identify the destination router of an incoming packet. It is required by the Frame Relay switch or DCE to determine the path for forwarding the packet to its destination.
How does DLCI work?
When a packet is received by a DCE, it identifies the DLCI and determines the destination router. The DLCI is locally significant, which means that the same DLCI can be used by different endpoints. But, it cannot be the same for two different destinations as it would create ambiguity for the DCE in selecting the right destination. To resolve this issue, each endpoint is assigned with a unique DLCI that is used for communication.
Benefits of DLCI
DLCI helps to efficiently route the frames to the correct destination, thus saving the bandwidth as it is shared among all the DCEs in the network. It also allows communication with multiple sites by configuring multiple DLCIs. The Committed Information Rate (CIR) ensures a minimum bandwidth for the service.
UNI and DLCI
The User Network Interface or UNI is the boundary between the FRAD and the Frame Relay network. It works with DLCI to specify the endpoint for a virtual circuit. The DLCI numbers are assigned by the user and usually range between 1 and 1022.
Popular Frame Relay PVCs
Frame Relay PVCs or Permanent Virtual Circuits are widely used for communication between enterprise circuits. PVCs offer extremely reliable and secure communication with a minimum requirement of leased lines. Other forms of carrier-provisioned Frame Relay virtual circuits are SVC and Soft PVC.
FAQs
What is the full form of DLCI?
DLCI stands for Data Link Connection Identifier and is a unique number used to identify the destination router for an incoming packet.
What is the UNI in Frame Relay?
The User Network Interface or UNI is the interface between the Frame Relay Access Device (FRAD) and the Frame Relay network.
What is the benefit of using Frame Relay PVCs?
Frame Relay PVCs offer reliable and secure communication between enterprise circuits with a minimum requirement of leased lines. It also saves bandwidth as it is shared among all the DCEs in the network.
Conclusion
In summary, DLCI is a unique number used in Frame Relay networks to identify the destination router of an incoming packet. It helps in efficient routing and saves bandwidth while allowing communication with multiple sites. The UNI interface works with DLCI to specify the endpoint for communication.
