Article ID: 15105
Products
C5-Series, firmware 6.71.01.0067 and higher
B5-Series, firmware 6.71.01.0067 and higher
A4-Series, firmware 6.71.01.0067 and higher
Changes
Enabled IGMP Snooping with L2 Querier election; for example on VLAN 196:
code:set igmpsnooping adminmode enable
code:set igmpsnooping querier enable
code:set igmpsnooping 196 enable
code:set igmpsnooping querier 196 enable
code:set igmpsnooping querier 196 address 10.26.196.23
code:set igmpsnooping querier election participate 196 enable
Deployed two or more such systems into the network, so that they negotiate for the Querier role.
Symptoms
Each non-querier system cycles between Non-Querier and Querier states; remaining Non-Querier for about 60 seconds, briefly moving to Querier, then reverting back to Non-Querier to repeat the cycle.
For example:
C5(su)->
show igmpsnooping querier detail
Last Querier
VLAN ID Address IGMP Version
------- ---------------- ------------
196 10.26.196.1 v2
197 10.26.197.1 v2
198 10.26.198.1 v2
199 10.26.199.1 v2
Global IGMP Snooping querier status
-----------------------------------
IGMP Snooping Querier Mode Enable
Querier Address 0.0.0.0
IGMP Version 2
Querier Query Interval 125
Querier Expiry Interval 60
VLAN 196 : IGMP Snooping querier status
----------------------------------------------
IGMP Snooping Querier VLAN Mode Enable
Querier Election Participate Mode Enable
Querier VLAN Address 10.26.196.23
Operational State Non-Querier
Last Querier Address 10.26.196.1
Operational version 2
Operational Max Resp Time 11
C5(su)->
show igmpsnooping querier detail
. . .
Operational State Querier
. . .
C5(su)->
show igmpsnooping querier detail
. . .
Operational State Non-Querier
. . .
C5(su)->
Cause
The Querier Expiry Interval (default 60 seconds) should not be less than the Querier Query Interval (default 125 seconds).
The Querier Expiry Interval is expiring all local knowledge of a previously established active querier before the Querier Query Interval triggers that active querier to send out a general query refresh. As a result, there is a period of time when this Non-Querier becomes what it believes is the sole Querier, resulting in multiple queriers on the VLAN.
Solution/Workaround
To be corrected in a future firmware release.
Contact the GTAC for an update, as necessary.
Workaround:
On each affected system, issue the command '
code:set igmpsnooping querier timer expiry 255
', which will make the local device the querier only if the previously known querier is no longer performing that function.
