06-26-2023 12:36 PM - edited 06-26-2023 12:37 PM
Hello,
I have a pair of Nexus 5548 in VPC and one VLAN used for multicast. A 3750X stack is connected to Nexus-1 and Nexus-2 through a port-channel. The issue I am seeing is that the 3750 sees the IGMP querier changes from time to time between the HSRP IPs of the SVIs:
IDF-3750X#sh ip igmp snooping querier | inc 819
819 172.30.19.2 v3 Po10
IDF-3750X#sh ip igmp snooping querier | inc 819
819 172.30.19.3 v3 Po10
IDF-3750X#sh ip igmp snooping querier vlan 819
IP address : 172.30.19.2
IGMP version : v3
Port : Po10
Max response time : 10s
Query interval : 125s
Robustness variable : 2
IDF-3750X#sh ip igmp snooping querier vlan 819
IP address : 172.30.19.3
IGMP version : v3
Port : Po10
Max response time : 10s
Query interval : 125s
Robustness variable : 2
SVIs are configured as follows:
CORE-1# sh run int vlan 819
interface Vlan819
description AUDIO
no shutdown
ip address 172.30.19.3/24
ip pim sparse-mode
ip pim dr-priority 10
ip igmp version 3
hsrp version 2
hsrp 819
preempt
ip 172.30.19.1
CORE-2# sh run int vlan 819
interface Vlan819
description AUDIO
no shutdown
ip address 172.30.19.2/24
ip pim sparse-mode
ip igmp version 3
hsrp version 2
hsrp 819
preempt
priority 110
ip 172.30.19.1
I did a pcap at the switch on each port-channel member on VLAN 819 and there are PIM hellos and IGMP query from each of the SVI IPs.
So is this expected? the switch keeps changing what IPs it sees as the querier and the traffic during those time are sent to new querier? How can I make this work to make the switch seeing a single querier all the time on that VLAN and if there is a failure then the standby HSRP IP being the querier.
the PIM-DR config I added to see if it helped but it didn't.
Thanks
Thanks
06-26-2023 12:55 PM
I discovered that each Nexus SVI from time to time see themselves as the active querier: (these output was taken at the same time) and during that brief time there was no querier showing on any of the Nexus:
CORE-1# sh ip igmp snooping querier | inc 819
CORE-1# sh ip igmp snooping querier
Vlan IP Address Version Expires Port
150 172.16.50.1 v2 00:02:34 Vlan150 (internal)
250 10.35.250.253 v2 00:02:49 Vlan250 (internal)
502 172.17.2.2 v2 00:02:48 Vlan502 (internal)
504 172.17.4.2 v2 00:02:37 Vlan504 (internal)
CORE-2# sh ip igmp snooping querier
Vlan IP Address Version Expires Port
150 172.16.50.1 v2 00:03:59 port-channel4096
250 10.35.250.253 v2 00:04:01 port-channel4096
502 172.17.2.2 v2 00:04:10 port-channel4096
504 172.17.4.2 v2 00:04:06 port-channel4096
CORE-1# sh ip igmp interface vlan 819
IGMP Interfaces for VRF "default"
Vlan819, Interface status: protocol-up/link-up/admin-up
IP address: 172.30.19.3, IP subnet: 172.30.19.0/24
Active querier: 172.30.19.3, version: 3, next query sent in: 00:00:10
Membership count: 67
Old Membership count 0
IGMP version: 3, host version: 3
IGMP query interval: 125 secs, configured value: 125 secs
IGMP max response time: 10 secs, configured value: 10 secs
IGMP startup query interval: 31 secs, configured value: 31 secs
IGMP startup query count: 2
IGMP last member mrt: 1 secs
IGMP last member query count: 2
IGMP group timeout: 260 secs, configured value: 260 secs
IGMP querier timeout: 255 secs, configured value: 255 secs
IGMP unsolicited report interval: 10 secs
IGMP robustness variable: 2, configured value: 2
IGMP reporting for link-local groups: disabled
IGMP interface enable refcount: 1
IGMP interface immediate leave: disabled
IGMP VRF name default (id 1)
IGMP Report Policy: None
IGMP State Limit: None
IGMP interface statistics: (only non-zero values displayed)
General (sent/received):
v2-queries: 0/27, v2-reports: 0/580187, v2-leaves: 0/913
v3-queries: 16129/88823, v3-reports: 0/1049461
Errors:
Interface PIM DR: Yes
Interface vPC SVI: Yes
Interface vPC CFS statistics:
DR queries sent: 1
DR queries rcvd: 1
DR updates sent: 1
DR updates rcvd: 22
CORE-2# sh ip igmp interface vlan 819
IGMP Interfaces for VRF "default"
Vlan819, Interface status: protocol-up/link-up/admin-up
IP address: 172.30.19.2, IP subnet: 172.30.19.0/24
Active querier: 172.30.19.2, version: 3, next query sent in: 00:01:33
Membership count: 67
Old Membership count 0
IGMP version: 3, host version: 3
IGMP query interval: 125 secs, configured value: 125 secs
IGMP max response time: 10 secs, configured value: 10 secs
IGMP startup query interval: 31 secs, configured value: 31 secs
IGMP startup query count: 2
IGMP last member mrt: 1 secs
IGMP last member query count: 2
IGMP group timeout: 260 secs, configured value: 260 secs
IGMP querier timeout: 255 secs, configured value: 255 secs
IGMP unsolicited report interval: 10 secs
IGMP robustness variable: 2, configured value: 2
IGMP reporting for link-local groups: disabled
IGMP interface enable refcount: 1
IGMP interface immediate leave: disabled
IGMP VRF name default (id 1)
IGMP Report Policy: None
IGMP State Limit: None
IGMP interface statistics: (only non-zero values displayed)
General (sent/received):
v2-queries: 0/27, v2-reports: 0/841548, v2-leaves: 0/915
v3-queries: 55295/72729, v3-reports: 0/1276255
Errors:
Packets with Local IP as source: 0, Source subnet check failures: 0
Query from non-querier:16129
Interface PIM DR: vPC Peer
Interface vPC SVI: Yes
Interface vPC CFS statistics:
DR queries sent: 1
DR queries rcvd: 1
DR updates sent: 1
DR updates rcvd: 22
After a while in that weird state it converges and either .2 or .3 are seeing as the querier on both Nexus. It continues on that behavior all the time.
CORE-1# sh ip igmp interface vlan 819
IGMP Interfaces for VRF "default"
Vlan819, Interface status: protocol-up/link-up/admin-up
IP address: 172.30.19.3, IP subnet: 172.30.19.0/24
Active querier: 172.30.19.2, expires: 00:02:31, querier version: 3
CORE-2# sh ip igmp interface vlan 819
IGMP Interfaces for VRF "default"
Vlan819, Interface status: protocol-up/link-up/admin-up
IP address: 172.30.19.2, IP subnet: 172.30.19.0/24
Active querier: 172.30.19.2, version: 3, next query sent in: 00:00:23
What I am missing here? Is there any particular debug/log to understand why is this happening?
06-26-2023 12:57 PM
What the hell??
CORE-2# sh ip igmp snooping querier | inc 819
819 172.30.19.3 v3 00:03:16 port-channel4096
CORE-2# sh ip igmp interface vlan 819 | inc Active
Active querier: 172.30.19.2, version: 3, next query sent in: 00:00:43
CORE-2#
Shouldn't it be like CORE-1:
CORE-1# sh ip igmp snooping querier | inc 819
819 172.30.19.2 v3 00:03:40 port-channel4096
CORE-1# sh ip igmp interface vlan 819 | inc Active
Active querier: 172.30.19.2, expires: 00:03:43, querier version: 3
CORE-1#
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