Инструкции По Установке для 3com S7906E

 

1-6 

You can configure the IGMP snooping proxying function on an edge device, which then can represent 

its attached hosts to send membership reports and leave messages, thus reducing the number of IGMP 

reports and leave messages sent to its upstream device. The device configured with IGMP snooping 

proxying is called an IGMP snooping proxy. It is a host from the perspective of its upstream device.  

 

Even though an IGMP snooping proxy is a host from the perspective of its upstream device, the IGMP 

membership report suppression mechanism for hosts does not take effect on it. For the IGMP report 

suppression mechanism for hosts, refer to IGMP Configuration in the IP Multicast volume.  

 

Figure 1-3 Network diagram for IGMP snooping proxying  

 

 

 

As shown in 

, Switch A works as an IGMP Snooping proxy. It represents its attached hosts to 

send membership reports and leave messages to Router A.  

 describes how an IGMP snooping proxy processes IGMP messages.  

Table 1-2 IGMP message processing on an IGMP snooping proxy 

General query 

When receiving an IGMP general query, the proxy forwards it to all ports but the 
receiving port. In addition, the proxy generates a report according to the group 
memberships it maintains and sends the report out all router ports.  

Group-specific 
query 

In response to the IGMP group-specific query for a certain multicast group, the 
proxy sends the report to the group out all router ports if the forwarding entry for 
the group still contains a member port.