Chapter 10 - WAN Link Protocols | 165 |
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The Data Link Connection Identifier (DLCI) is a number which uniquely identifies one end of a Permanent Virtual Circuit (PVC) to your Frame Relay carrier’s Frame Relay switch. The DLCIs are not interchangeable between the two ends of a PVC, since they only identify one end of the PVC. Unless you use the correct DLCI numbers at each end of your PVC,
This database lets you create static mappings between the Frame Relay PVCs on this interface (identified by their DLCI number) and the protocol (e.g. IP, IPX, etc.) addresses of the router interfaces at the far ends of the PVCs.
ϖNote: If the router at the far end of a PVC is another Compatible Systems router, you will generally not need any entries in the DLCI database for it. Compatible Systems routers use the IARP (Inverse Address Resolution Protocol) to dynamically create the same type of mappings that are manually entered in the DLCI database.
ϖNote: A router will not use IARP to attempt to discover addresses for a particular protocol on a PVC if there is already a DLCI database entry for the PVC for that protocol. Therefore, if you wish to use IARP to dynamically discover the addresses at the far end of a PVC, do not make any entries for its DLCI number in the DLCI database.
ϖNote: Frame Relay DLCIs must be statically mapped using the DLCI mapping database when IP subinterfaces are in use, because IARP can only resolve a physical port, not a logical subinterface on that port.
>DLCI #
This is the decimal number between 16 and 991 which uniquely identifies this end of a PVC. A DLCI number will be provided to you by your Frame Relay carrier for each end of each PVC.
IP Address
This is the IP address of the router interface at the other end of the PVC. It should be entered in standard IP
AppleTalk Address
This is the AppleTalk address of the interface of the router WAN interface at the other end of the PVC. It should be entered in decimal as a “network:node” pair (e.g. 24:1).
The AppleTalk network number must be between 1 and 65,279. The node address must be between 1 and 254.
