Operation Manual – Multicast Protocol
H3C S3610&S5510 Series Ethernet Switches
Chapter 2 IGMP Snooping Configuration
2-20
Note:
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When the number of multicast groups a port has joined reaches the maximum
number configured, the system deletes all the forwarding entries persistent to that
port from the IGMP Snooping forwarding table, and the hosts on this port need to
join the multicast groups again.
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If you have configured static or simulated joins on a port, however, when the number
of multicast groups on the port exceeds the configured threshold, the system
deletes all the forwarding entries persistent to that port from the IGMP Snooping
forwarding table and applies the static or simulated joins again, until the number of
multicast groups joined by the port comes back within the configured threshold.
2.6.6 Configuring Multicast Group Replacement
For some special reasons, the number of multicast groups that can be joined on the
current switch or port may exceed the number configured for the switch or the port. In
addition, in some specific applications, a multicast group newly joined on the switch
needs to replace an existing multicast group automatically. A typical example is
“channel switching”, namely, by joining a new multicast group, a user automatically
switches from the current multicast group to the new one.
To address such situations, you can enable the multicast group replacement function
on the switch or certain ports. When the number of multicast groups joined on the
switch or a port has joined reaches the limit:
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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.
I. 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
—
Configure multicast group
replacement
overflow-replace
[
vlan
vlan-list
]
Required
Disabled by default
