3Com S7902E, Configuration Manual

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If the multicast group replacement feature is enabled, the newly joined multicast group
automatically replaces an existing multicast group with the lowest address.
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If the multicast group replacement feature is not enabled, new IGMP reports will be automatically
discarded.
Configuring multicast group replacement globally
Follow these steps to configure multicast group replacement globally:
To do... Use the command... Remarks
Enter system view system-view —
Enter IGMP snooping view igmp-snooping —
Enable multicast group
replacement overflow-replace [ vlan
vlan-list ]
Required
Disabled by default
Configuring multicast group replacement on a port or a group of ports
Follow these steps to configure multicast group replacement on a port or a group of ports:
To do... Use the command... Remarks
Enter system view system-view —
interface interface-type
interface-number
Enter Ethernet port/ONU
port/Layer 2 aggregate
interface view or port group
view
port-group manual
port-group-name
Required
Use either approach
Enable multicast group
replacement
igmp-snooping
overflow-replace
[ vlan
vlan-list ]
Required
Disabled by default
Be sure to configure the maximum number of multicast groups allowed on a port (refer to Configuring
Maximum Multicast Groups that Can Be Joined on a Port ) before enabling multicast group replacement.
Otherwise, the multicast group replacement functionality will not take effect.
Configuring 802.1p Precedence for IGMP Messages
You can change 802.1p precedence of IGMP messages so that they can be assigned higher forwarding
priority when congestion occurs on their outgoing ports.
Configuring 802.1p precedence for IGMP messages globally
Follow these steps to configure 802.1p precedence for IGMP messages globally:
To do... Use the command... Remarks
Enter system view system-view —