The Frame Relay LMI conveys the PVC status from the switch to you. The Frame Relay router
talks to the Frame Relay switch using LMI. There are three standards. Two of them, the ANSI
and the ITU, are very similar. The third standard, Cisco LMI, is a public specification by four
companies in 1988, including Stratacom, Northern Telecom, Cisco, and DEC. They are
commonly known as the Gang of Four.
switch and the router. This message is locally significant only, not end-to-end. Part of this
signaling is keepalive, or status-inquiry messages every 10 seconds to make sure that the other
end of the circuit is still there. The router needs to see a response to this short status inquiry to
mark the line protocol as up.
DLCI numbers assigned to that router's serial interface. This is when you should see the PVCs
become active. If a change occurs in the PVC status, the router will not mark the PVC down
until the next full status inquiry (every 60 seconds), unless you're using Cisco LMI on both the
router and the switch and have configured asynchronous updates on the switch.
if Router B's circuit goes down, Router A's interface remains up but shows Inactive for DLCI
100 upon issuance of the command show frame-relay pvc.