Data Link Connection Identifier
A Data Link Connection Identifier (DLCI) is the number assigned to a virtual circuit on a frame relay user-to-network interface (UNI), or network-to-network interface (NNI). In the two-octet frame relay frame header, the DLCI field is 10 bits long, permitting a total of 1024 DLCI values, some of which are reserved:
- DLCI 0 (zero) and 1023 are reserved for management purposes, including the Local Management Interface (LMI).
- DLCI 1-15 and 1008-1022 are reserved for future use.
- DLCI 16 to 991 are available for subscriber use.