R2511-HP MSR Router Series IP Multicast Configuration Guide(V5)
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• If the IPv6 multicast group replacement is disabled, the IGMP snooping-enabled router or the port
discards IGMP reports for joining a new IPv6 multicast group.
In some specific applications, such as channel switching, a newly joined multicast group must
automatically replace an existing multicast group. In this case, the function of IPv6 multicast group
replacement must also be enabled so a user can switch from the current multicast group to a new one.
IMPORTANT:
Be sure to confi
g
ure the maximum number of multicast
g
roups that a port can join to a value other than the
default one (see "Setting the maximum number of multicast grou
ps that a port can join") before enablin
g
multicast group replacement. Otherwise, the multicast group replacement functionality will not take effect.
Enabling multicast group replacement globally
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter IGMP-snooping view.
igmp-snooping N/A
3. Enable multicast group
replacement.
overflow-replace [ vlan vlan-list ] Disabled by default.
Enabling multicast group replacement on a port
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view, or
enter port group view.
• Enter Layer 2 Ethernet interface
view or Layer 2 aggregate
interface view:
interface interface-type
interface-number
• Enter port group view:
port-group manual
port-group-name
Use either command.
3. Enable multicast group
replacement.
igmp-snooping overflow-replace
[ vlan vlan-list ]
Disabled by default.
Setting the 802.1p precedence for IGMP messages
When congestion occurs on outgoing ports of a switch, it forwards IGMP messages according to their
802.1p priorities, from highest to lowest. You can assign higher forwarding priority to IGMP messages by
changing their 802.1p precedence.
Setting the 802.1p precedence for IGMP messages globally
Step Command Remarks
1. Enter system view.
system-view N/A
2. Enter IGMP-snooping view.
igmp-snooping N/A
3. Set the 802.1p precedence for
IGMP messages.
dot1p-priority priority-number
The default 802.1p precedence for
IGMP messages is 0.