8.4. Troubleshoot WAN implementation issues

If you have a point-to-point link, but the encapsulations aren't the same, the link will never come up. Figure 8.4 shows one link with PPP and one with HDLC.

Figure 8.4. Mismatched WAN encapsulations

Look at router Pod1R1 in this output:

Pod1R1#sh int s0/0
Serial0/0 is up, line protocol is down
  Hardware is PowerQUICC Serial
  Internet address is 10.0.1.1/24
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 254/255, txload 1/255, rxload 1/255
  Encapsulation PPP, loopback not set
  Keepalive set (10 sec)
  LCP REQsent
Closed: IPCP, CDPCP

The serial interface is down, and LCP is sending requests but ...

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