3com WX3000 Manuel D’Utilisation

 

2-7 

Follow these steps to enable fast leave processing in Ethernet view: 

Enter system view  

system-view — 

Enter Ethernet port view  

interface interface-type 
interface-number 

— 

Enable fast leave processing 
for specific VLANs 

igmp-snooping fast-leave 
[ vlan vlan-list ] 

Required 

By default, the fast leave 
processing feature is disabled. 

 

z 

The fast leave processing function works for a port only if the host attached to the port runs IGMPv2 

or IGMPv3. 

z 

The configuration performed in system view takes effect on all ports of the device if no VLAN is 

specified; if one or more VLANs are specified, the configuration takes effect on all ports in the 

specified VLAN(s). 

z 

The configuration performed in Ethernet port view takes effect on the port no matter which VLAN it 

belongs to if no VLAN is specified; if one or more VLANs are specified, the configuration takes 

effect on the port only if the port belongs to the specified VLAN(s). 

z 

If fast leave processing and unknown multicast packet dropping are enabled on a port to which 

more than one host is connected, when one host leaves a multicast group, the other hosts 

connected to port and interested in the same multicast group will fail to receive multicast data for 

that group. 

 

On an IGMP Snooping-enabled device, the configuration of a multicast group allows the service 

provider to define restrictions on multicast programs available to different users.  

In an actual application, when a user requests a multicast program, the user’s host initiates an IGMP 

report. Upon receiving this report message, the device checks the report against the ACL rule 

configured on the receiving port. If the receiving port can join this multicast group, the device adds this 

port to the IGMP Snooping multicast group list; otherwise the device drops this report message. Any 

multicast data that has failed the ACL check will not be sent to this port. In this way, the service provider 

can control the VOD programs provided for multicast users. 

Make sure that an ACL rule has been configured before configuring this feature.