Nexus5k with FEX 2K_ %IGMP-4-QUERY_DROP_ON_SAT_PORT

[Hongju Jung]

Dear on duty

we have some logging message as a below

2014 Apr 21 21:49:26.044 U8_9_Service_SW_1 %VSHD-5-VSHD_SYSLOG_CONFIG_I:
Configured from vty by admin on 172.21.1
00.4@pts/0
2014 Apr 21 21:49:58.716
U8_9_Service_SW_1 %VSHD-5-VSHD_SYSLOG_CONFIG_I: Configured from vty by socool on
172.21.
86.85@pts/1
2014 Apr 21
21:51:01.243 U8_9_Service_SW_1 %IGMP-4-QUERY_DROP_ON_SAT_PORT:  igmp
[3578]  Since router ports on fe
xes is not supported, dropping queries
received on fex interface Eth106/1/40.
2014 Apr 21 21:53:06.685
U8_9_Service_SW_1 last message repeated 1 time
2014 Apr 21 21:53:11.821
U8_9_Service_SW_1 %VSHD-5-VSHD_SYSLOG_CONFIG_I: Configured from vty by admin on
172.21.1
00.4@pts/0
2014 Apr 21
21:54:57.988 U8_9_Service_SW_1 last message repeated 1 time
2014 Apr 21
21:55:12.124 U8_9_Service_SW_1 %IGMP-4-QUERY_DROP_ON_SAT_PORT:  igmp
[3578]  Since router ports on fe
xes is not supported, dropping queries
received on fex interface Eth106/1/40.
2014 Apr 21 21:56:02.721
U8_9_Service_SW_1 %VSHD-5-VSHD_SYSLOG_CONFIG_I: Configured from vty by admin on
172.21.1
00.4@pts/0
2014 Apr 21
21:56:57.742 U8_9_Service_SW_1 last message repeated 1 time
2014 Apr 21
21:57:17.565 U8_9_Service_SW_1 %IGMP-4-QUERY_DROP_ON_SAT_PORT:  igmp
[3578]  Since router ports on fe
xes is not supported, dropping queries
received on fex interface Eth106/1/40.
2014 Apr 21 21:59:23.006
U8_9_Service_SW_1 last message repeated 1 time
2014 Apr 21 22:00:09.390
U8_9_Service_SW_1 %VSHD-5-VSHD_SYSLOG_CONFIG_I: Configured from vty by admin on
172.21.1
00.4@pts/0
2014 Apr 21
22:01:28.446 U8_9_Service_SW_1 %IGMP-4-QUERY_DROP_ON_SAT_PORT:  igmp
[3578]  Since router ports on fe
xes is not supported, dropping queries
received on fex interface Eth106/1/40.
2014 Apr 21 22:01:32.715
U8_9_Service_SW_1 %LIBIFMGR-5-ALL_COUNTERS_CLEARED: All interface counters
cleared by us
er
2014 Apr 21 22:03:33.887 U8_9_Service_SW_1
%IGMP-4-QUERY_DROP_ON_SAT_PORT:  igmp [3578]  Since router ports on
fe
xes is not supported, dropping queries received on fex interface
Eth106/1/40.
2014 Apr 21 22:05:39.330 U8_9_Service_SW_1 last message repeated
1 time
2014 Apr 21 22:07:44.768 U8_9_Service_SW_1 last message repeated 1
time
2014 Apr 21 22:09:50.209 U8_9_Service_SW_1 last message repeated 1
time
2014 Apr 21 22:11:55.649 U8_9_Service_SW_1 last message repeated 1
time
2014 Apr 21 22:14:01.090 U8_9_Service_SW_1 last message repeated 1
time
2014 Apr 21 22:16:06.530 U8_9_Service_SW_1 last message repeated 1

ther is looks like IGMP message droppoing on the system but we not configured multicast routing protocol yet.

Anybody know it why come up the theose kind message and what is problem with them now.

Please let me know how to resolve the issue or guide for troubleshooting for us

thanks.
 

[Vishal Mehta]

Hello,

"IGMP-4-QUERY_DROP_ON_SAT_PORT" log messages are the result of enhancement CSCug39029.

https://tools.cisco.com/bugsearch/bug/CSCug39029/?reffering_site=dumpcr

Starting NX-OS 5.2(1)N1(5), IGMP general queries received on FEX interfaces would be dropped preventing from FEX interface becoming an mrouter port.

This should not be causing any service impact or forwarding issues.

Mrouter/IGMP querier is not supported on FEX HIF ports and the above enhancement was added to drop IGMP Query packets and log an error message.

In order to get rid of the messages, you have the following options:

option1 - suppress these log messages with command: Nexus5000(config)# logging level igmp 3

option2 - disable IGMP snooping globally: Nexus5000(config)# no ip igmp snooping

option3 - disable multicast on the end host connected to this port

Please let me know if you need more details.

Also kindly open TAC case with Nexus 5000 keywords and we can get in-depth analysis done

Hope this answer helps!

Thanks

Vishal

[Roberto Pancrazio Loiudice]

Hello everyone,

the bug CSCug39029 says: 

Symptom:
Mrouter port on FEX Is not supported . When you have multiple mrouter port on the same fex in same vlan, if the host sends igmp report, then we would flood the igmp on the same interface where it was received.Issue can be observed even if you have mrouter port across diff fex in same vlan (as the packets are flood to vlan). 

I don't understand why the Nexus will flood the igmp report back to the interface where it was received. Could anybody explain me why?

Thanks.

Best regards,

Roberto Loiudice