33
Configuration restrictions and guidelines
When you set the maximum number of multicast groups on a port, follow these restrictions and
guidelines:
•
This configuration takes effect only on the multicast groups that a port joins dynamically.
•
If the number of multicast groups on a port exceeds the limit, the system removes all the
forwarding entries related to that port. The receiver hosts attached to that port can join multicast
groups again before the number of multicast groups on the port reaches the limit.
Configuration procedure
To set the maximum number of multicast groups 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.
interface
interface-type
interface-number
N/A
3.
Set the maximum number of
multicast groups on a port.
igmp-snooping group-limit
limit
[
vlan vlan-list
]
By default, no limit is placed on
the maximum number of multicast
groups on a port.
Enabling multicast group replacement
This feature enables the device to replace an existing group with a newly joined group when the
number of groups exceeds the upper limit. This feature is typically used in the channel switching
application. Without this feature, the device discards IGMP reports for new groups, and the user
cannot change to the new channel.
Configuration restrictions and guidelines
When you enable multicast group replacement, follow these restrictions and guidelines:
•
This configuration takes effect only on the multicast groups that a port joins dynamically.
•
You can enable this feature globally for all ports in IGMP-snooping view or for a port in interface
view. For a port, the port-specific configuration takes priority over the global configuration.
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 globally.
overflow-replace
[
vlan vlan-list
] By default, multicast group
replacement is disabled globally.
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.
interface
interface-type
interface-number
N/A
3.
Enable multicast group
replacement on a port.
igmp-snooping
overflow-replace
[
vlan vlan-list
]
By default, multicast group
replacement is disabled on a port.
