Troubleshooting Vrrp - 3Com 5500-SI Configuration Manual

162 C 12: VRRP C
HAPTER

Troubleshooting VRRP

ONFIGURATION
b Create backup group 1.
[LSW-B-Vlan-interface2] vrrp vrid 1 virtual-ip 202.38.160.111
c Create backup group 2.
[LSW-B-Vlan-interface2] vrrp vrid 2 virtual-ip 202.38.160.112
d Set the priority for backup group 2.
[LSW-B-Vlan-interface2] vrrp vrid 2 priority 110
Normally, multiple backup groups are used in actual use.
As the configuration of VRRP is not very complicated, almost all the malfunctions can
be located through viewing the configuration and debugging information. Here are
some possible failures you might meet and the corresponding troubleshooting
methods.
Symptom 1: Frequent prompts of configuration errors on the console
This indicates that incorrect VRRP packets are received. It may be because of the
inconsistent configuration of the switches within the backup group, or the attempt of
other devices sending out illegal VRRP packets. The first possible fault can be solved
through modifying the configuration. And as the second possibility is caused by the
malicious attempt of some devices, non-technical measures should be resorted to.
Symptom 2: More than one master existing within a backup group
There are also 2 reasons. One is short time coexistence of many master switches,
which is normal and needs no manual intervention. Another is the long time
coexistence of many master switches, which may be because the original master
switch and other member switches in a backup group cannot receive VRRP packets
from each other, or receive some illegal packets.
To solve such a problem, an attempt should be made to ping among these masters
and if such an attempt fails, check the connectivity between related devices. If they
can be pinged through, check VRRP configuration. For the configuration of a VRRP
backup group, complete consistency for the number of virtual IP addresses, each
virtual IP address, timer duration and authentication type configured on each member
switch must be guaranteed.
Symptom 3: Frequent switchover of VRRP state
Such a problem occurs when the backup group timer duration is too short. So the
problem can be solved through prolonging this duration or configuring the
preemption delay period.