5.7 Monitoring the ISDN Interface
5.7.4 Troubleshooting MLP
The debug dialer command indicates whether the multilink is up after authentication. As shown in Figure , the debug dialer command also shows when the overload occurs.

Note: Click on the topology to view the command output.

If the second link fails to come up, use Table to troubleshoot your MLP configuration.

Following are different debugging commands that are used to monitor MLP in an ISDN DDR environment:

  • The debug ppp multilink command displays packet sequence numbers. It is useful only as a last resort because it does not help troubleshoot when connections are not being bundled.
  • The debug ppp negotiation command displays the Maximum-Receive-Reconstructed Unit (MRRU) option negotiation.
  • The debug ppp authentication command is useful for displaying the steps in the PPP authentication process.
  • The debug isdn events command also displays information that is useful for monitoring and troubleshooting MLP.