Troubleshooting Guide

Variable Value
file [tail] Displays the trace results saved to a file.
level Displays the current trace level for all modules.
modid-list Specifies the module ID list.
Troubleshooting IGMPv3 backwards compatibility
If you configure the switch to operate in v2-v3 compatibility mode, the switch supports all IGMPv2
and v3 messages. The switch parses the group address of the messages. If the group address is
out of SSM range and it is a v3 message, the switch drops the message. If it is a v2 message, IGMP
snoop processes handle the message.
To troubleshoot issues with the IGMPv3 backwards compatibility feature, perform the following
procedure.
Procedure
1. Enter Privileged EXEC mode:
enable
2. Verify that the SSM static channel is configured for the v1/v2 joins received. Display the
configured SSM static channels:
show ip igmp ssm-map
3. Verify that the SSM group range is configured for the v1/v2 joins received. Display the
configured SSM group range:
show ip igmp ssm
Example
Display the configured SSM static channels and display the configured SSM group range:
Switch:>enable
Switch:1#show ip igmp ssm-map
================================================================================
Igmp Ssm Channel
================================================================================
GROUP SOURCE MODE ACTIVE STATUS
--------------------------------------------------------------------------------
233.252.0.1 192.0.2.200 dynamic false enabled
233.252.0.2 192.0.2.200 dynamic false enabled
233.252.0.3 192.0.2.200 dynamic false enabled
233.252.0.4 192.0.2.200 dynamic false enabled
233.252.0.5 192.0.2.200 dynamic false enabled
233.252.0.6 192.0.2.200 dynamic false enabled
233.252.0.7 192.0.2.200 dynamic false enabled
233.252.0.8 192.0.2.200 dynamic false enabled
233.252.0.9 192.0.2.200 dynamic false enabled
233.252.0.10 192.0.2.200 dynamic false enabled
10 out of 10 entries displayed
Multicast feature troubleshooting
January 2017 Troubleshooting 265
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