Troubleshoot a serial PPP link

This lab uses two Cisco routers with serial ports and a separate Ethernet path.

Check the port inventory before configuring the serial link.

Set both serial interfaces to use PPP and assign addresses on the same subnet.

Verify that the line is up and both PPP control protocols are open.

Change the far end to HDLC to reproduce an encapsulation mismatch.

The PPP session closes and the serial probe fails while Ethernet still works.

Restore PPP on the far end and verify that the serial connection works again.