Frame-Relay DLCI values

When implementing a Frame-Relay topology, Data Link Connection Identifiers (DLCIs) are used as the Layer 2 addressing scheme. DLCIs are 10 bit values that identify virtual circuits (VCs).

These values must be locally unique (within the scope of the local device). Take a look at the following Frame-Relay topology:


The DLCI values on the hub must be unique for each VC that terminates on the Hub. The values of the DLCIs on the spokes can be different or can be the same, it makes no difference.

It is typically best practice to use the same DLCI numbers on either end of a VC. This makes it easier to manage a network, especially one with many spokes.