16.2.4 Checking IGMP info

The following are the types of information you can check in the IPv4 multicast routing information for the Switch when the IGMP functionality is set.

<Structure of this section>

(1) Interface information

Execute the show ip igmp interface command and check the following.

Check the interface within Address. If none exists, IGMP will not run on the interface. In the configuration, make sure that IGMP setting and IPv4 PIM-SM setting are enabled on the corresponding interface. In addition, check whether a failure has occurred on the interface.
Check the Group Count value (number of groups hosts have joined) for the target interface. If the value is 0, either groups hosts have joined might not exist, or the group member hosts might not advertise IGMP-Report. Check the hosts.
Check whether the version displayed in the Version field allows connection with the host used by the interface.

If a code is displayed in the Notice field, IGMP packets have been discarded. Use the code to determine why the packets were discarded.

Figure 16-15: Result of executing show ip igmp interface command
> show ip igmp interface Date 20XX/04/10 15:10:00 UTC Total: 5 Interfaces Address Interface Version Flags Querier Expires Group Count Notice 192.168.1.2 VLAN0001 2 S 192.168.1.2 - 2 192.168.2.2 VLAN0002 2 S 192.168.2.1 02:30 0 192.168.3.2 VLAN0003 3 192.168.3.1 00:50 2 192.168.30.2 VLAN0004 (3) 192.168.30.2 - 0 Q 192.168.40.2 VLAN0005 3 192.168.40.1 03:15 3 L

Figure 16-15: Result of executing show ip igmp interface command

> show ip igmp interface
Date 20XX/04/10 15:10:00 UTC
Total: 5 Interfaces
Address      Interface  Version  Flags  Querier     Expires  Group Count  Notice
192.168.1.2  VLAN0001      2     S      192.168.1.2    -               2
192.168.2.2  VLAN0002      2     S      192.168.2.1  02:30             0
192.168.3.2  VLAN0003      3            192.168.3.1  00:50             2
192.168.30.2 VLAN0004     (3)           192.168.30.2   -               0   Q
192.168.40.2 VLAN0005      3            192.168.40.1 03:15             3  L

(2) Group information

Execute the show ip igmp group command and check the groups displayed in the Group Address field. If there are none, check for the following:

The group members (hosts) might not advertise IGMP-Report. Check the hosts.
Check the version of the IGMP interfaces for the Switch and for each host, and make sure that the Switch can connect to the hosts.

If the hosts ignore IGMPv3-Query, IGMPv3 cannot be used. Set the IGMP version of the corresponding interface to 2.

Figure 16-16: Result of executing show ip igmp group command
> show ip igmp group brief Date 20XX/08/01 15:10:00 UTC Total: 7 groups Group Address Interface Version Mode Source Count 224.1.1.1 VLAN0001 2 EXCLUDE 0 232.1.1.2 VLAN0001 2 EXCLUDE 2 234.1.1.1 VLAN0003 2 EXCLUDE 1 234.1.1.2 VLAN0003 3 INCLUDE 1 232.1.1.1 VLAN0004 3 INCLUDE 1 232.1.1.3 VLAN0004 3 INCLUDE 2 235.1.1.1 VLAN0004 3 EXCLUDE 3

Figure 16-16: Result of executing show ip igmp group command

> show ip igmp group brief
Date 20XX/08/01 15:10:00 UTC
Total: 7 groups
Group Address   Interface       Version  Mode      Source Count
224.1.1.1       VLAN0001           2     EXCLUDE              0
232.1.1.2       VLAN0001           2     EXCLUDE              2
234.1.1.1       VLAN0003           2     EXCLUDE              1
234.1.1.2       VLAN0003           3     INCLUDE              1
232.1.1.1       VLAN0004           3     INCLUDE              1
232.1.1.3       VLAN0004           3     INCLUDE              2
235.1.1.1       VLAN0004           3     EXCLUDE              3