At times, the Layer 1 and 2 functions are operational, but IP communication is not occurring over the PVC. For a router to reach a remote router across the Frame Relay network, it must map the IP address of the remote router with the correct local DLCI. If the IP address of the remote router does not appear in the Frame Relay mapping table, it may not support Inverse ARP. It may require the IP address-to-DLCI mapping to be configured using the frame-relay map ip {ip address}{dlci} [broadcast] command.