Vrrp Troubleshooting - 3Com 3C13636 Configuration Manual

3Com Router 3000 Ethernet Family
Configuration Guide

3.5 VRRP Troubleshooting

The configuration of VRRP is simple. You can locate most of the problems by checking
the output of the display command and the debugging command. The following
present some troubleshooting cases.
Symptom 1:
The console screen displays error prompts frequently.
Solution:
Check that the received VRRP packets are correct.
The router may receive an incorrect VRRP packet for two reasons: its configuration is
inconsistent with that on another router in the standby group; a device is attempting to
send illegitimate VRRP packets. In the first case, modify the configuration. In the
second case, you must resort to non-technical measures.
Symptom 2:
Multiple masters are present in the same standby group.
Solution:
If presence of multiple masters lasts a short period, this is normal and requires no
manual intervention. If it lasts long, you must check that these masters can receive
VRRP packets and the received packets are legitimate.
Do the following:
Have these routers ping each other.
If they can be pinged, check that their configurations are consistent, making sure that
the same number of virtual IP addresses, the configured virtual IP addresses, timer
setting and authentication mode are configured for the same VRRP standby group.
If they cannot be pinged, check for other reasons.
Symptom 3:
Frequent VRRP state transition is present.
Solution:
Set the Adver_Timer of the standby group to a larger value or configure a preemption
delay.
3Com Corporation
3-12
Chapter 3 VRRP Configurations