Troubleshooting Igmp Snooping - 3Com 7757 Configuration Manual

440 C 43: IGMP S
HAPTER
Troubleshooting IGMP
Snooping
C
NOOPING ONFIGURATION
Configuration procedure
# Configure Router A.
<Router-A> system-view
[Router-A] multicast routing-enable
[Router-A] interface GigabitEthernet0/0/0
[Router-A-GigabitEthernet0/0/0] pim sm
[Router-A-GigabitEthernet0/0/0] igmp enable
[Router-A-GigabitEthernet0/0/0] quit
# Configure Switch B.
<SW7750> system-view
[SW7750] igmp-snooping enable
[SW7750] vlan 1024
[SW7750-vlan1024]igmp-snooping enable
[SW7750-vlan1024] multicast-vlan enable
[SW7750-vlan1024] quit
[SW7750] multicast-vlan 1024 subvlan 2 to 7
Symptom: Multicast function does not work on the switch.
Solution:
The reason may be:
1 IGMP Snooping is not enabled.
Use the display current-configuration command to check the status of IGMP
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Snooping.
If IGMP Snooping is disabled, check whether it is disabled globally or on the
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corresponding VLAN. If it is disabled globally, use the igmp-snooping enable
command in both system view and VLAN view to enable it both globally and
on the corresponding VLAN at the same time. If it is only disabled on the
corresponding VLAN, use the igmp-snooping enable command in VLAN view
only to enable it on the corresponding VLAN.
2 Multicast forwarding table set up by IGMP Snooping is wrong.
Use the display igmp-snooping group command to check if the multicast
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groups are expected ones.
If the multicast group set up by IGMP Snooping is not correct, contact your
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technical support personnel.
Continue with solution 3) if the second step does not work.
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If it is not the reason, the possible reason may be:
3 Multicast forwarding tables set up by IGMP Snooping is wrong.
Use the display mac-address vlan command to check whether the MAC
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multicast forwarding table set up in the vlan-id VLAN view is consistent with
the one set up by IGMP Snooping.
If they are not consistent, contact your technical support personnel.
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