3com S7906E Instruccion De Instalación

 

1-22 

On an IGMP snooping proxy, IGMP membership reports are suppressed if the entries for the 

corresponding groups exist in the forwarding table, no matter the suppression function is enabled or 

not. 

 

Configuring Maximum Multicast Groups that Can Be Joined on a Port  

By configuring the maximum number of multicast groups that can be joined on a port, you can limit the 

number of multicast programs on-demand available to users, thus to regulate traffic on the port.  

Follow these steps to configure the maximum number of multicast groups allowed on a port or ports:  

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 

Configure the maximum 
number of multicast groups 
allowed on the port(s)  

igmp-snooping group-limit 
limit [ vlan vlan-list ] 

Optional 

1000 by default.  

 

z 

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.  

z 

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.  

 

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: