Appendix; Processing Of Multicast Protocol Messages - HP 6125G Configuration Manual

The multicast group policy is not correctly applied.
•
• The function of dropping unknown multicast data is not enabled, so unknown multicast data is
flooded.
Solution
Use the display acl command to check the configured ACL rule. Make sure that the ACL rule
1.
conforms to the multicast group policy to be implemented.
Use the display this command in IGMP-snooping view or in the corresponding interface view to
2.
verify that the correct multicast group policy has been applied. If not, use the group-policy or
igmp-snooping group-policy command to apply the correct multicast group policy.
Use the display current-configuration command to verify that the function of dropping unknown
3.
multicast data is enabled. If not, use the drop-unknown or igmp-snooping drop-unknown
command to enable the function of dropping unknown multicast data.

Appendix

Processing of multicast protocol messages

With Layer 3 multicast routing enabled, an IGMP snooping–enabled switch processes multicast protocol
messages differently under different conditions, as follows:
If only IGMP is enabled on the switch, or if both IGMP and PIM are enabled on the switch, the
1.
switch does the following:
Maintains dynamic member ports or dynamic router ports according to IGMP packets
Maintains dynamic router ports according to PIM hello packets
If only PIM is enabled on the switch, the following occur:
2.
The switch broadcasts IGMP messages as unknown messages in the VLAN.
After receiving a PIM hello message, the switch maintains the corresponding dynamic router
port.
If IGMP is disabled on the switch, one of the following occurs:
3.
If PIM is disabled, the switch deletes all its dynamic member ports and dynamic router ports.
If PIM is enabled, the switch deletes only its dynamic member ports but not its dynamic router
ports.
NOTE:
On a switch with Layer-3 multicast routing enabled, use the display igmp group port-info command to
display Layer-2 port information. For more information about this command, see
Reference
.
If PIM is disabled on the switch, one of the following occurs:
4.
If IGMP is disabled, the switch deletes all its dynamic router ports.
If IGMP is enabled, the switch maintains all its dynamic member ports and dynamic router
ports.
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IP Multicast Command