H3C Technologies H3C SecPath F1000-E - Manual (Page 57)

13
Symptom 2
Physical link is down.
Solution
Check that
• The interface has been brought up.
• The interface has not been administratively shut down.
• LCP negotiation has passed.
Execute the display interface serial command to check the state of the interface. The output information
can be:
•
serial number is administratively down, line protocol is down
, which indicates that the
interface is shut down by the administrator.
•
serial number is down, line protocol is down
, which indicates that the interface is not activated
or the physical layer has not gone up yet.
•
serial number is up, line protocol is up
, which indicates that LCP negotiation succeeded.
•
serial number is up, line protocol is down
, which indicates that the interface is active, but
LCP negotiation failed.
Symptom 3
Configure an IPv6 address on a PPP-encapsulated interface when IPv6 is disabled. The PPP link fails
IPv6CP negotiation and cannot go up. After enabling IPv6, the interface still cannot go up.
Analysis
IPv6CP negotiation cannot succeed when IPv6 is disabled. As IPv6CP does not support re-negotiation,
IPv6CP negotiation cannot succeed even if you enable IPv6 subsequently.
Solution
To resolve the problem, do the following:
• Enable IPv6 before configuring an IPv6 address on a PPP link.
• If IPv6CP negotiation fails, re-enable the interface with the shutdown command and the undo
shutdown command to re-enable IPv6CP negotiation.