DLCI Addressing
The DLCI is an addressing mechanism used to identify a VC so that when multiple VCs use the same access link the Frame Relay switches know how to forward the frames to the correct remote sites.
Two important features of the DLCI are:
• The Frame Relay headers, which have a single DLCI field, not both Source and Destination DLCI fields.
• The local significance of the DLCI, which means that the addresses need to be unique only on the local access link. This is called local addressing.
Because there is only a single DLCI field in the Frame Relay header, Global addressing can be used, making DLCI addressing look like LAN addressing in concept. Global addressing is a way of choosing DLCI numbers when planning a Frame Relay network so that working with DLCIs is much easier.