Layer 2 Issues on the Access Link (Step 2)
If a router’s physical interface line status is up, but the line protocol status (second status code) is down, the link usually has a Layer 2 problem between the router and the local Frame Relay switch. With Frame Relay interfaces, the problem is often related to either the encapsulation command or the Frame Relay LMI.
The potential problem related to the encapsulation command is simple to check. If a router’s serial interface configuration omits the encapsulation frame-relay interface subcommand but the physical access link is working, the physical interface settles into an up/down state. If the configuration is unavailable, the show interfaces command can be used to see the configured encapsulation ...
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