Cisco Systems 3560 Manual Do Utilizador

You should only use the Immediate Leave feature on VLANs where a single host is connected to each 
port. If Immediate Leave is enabled in VLANs where more than one host is connected to a port, some 
hosts might inadvertently be dropped. 

For configuration steps, see the 

You can configure the time that the switch waits after sending a group-specific query to determine if 
hosts are still interested in a specific multicast group. The IGMP leave response time can be configured 
from 100 to 5000 milliseconds. The timer can be set either globally or on a per-VLAN basis. The VLAN 
configuration of the leave time overrides the global configuration.

For configuration steps, see the 

IGMP report suppression is supported only when the multicast query has IGMPv1 and IGMPv2 reports. 
This feature is not supported when the query includes IGMPv3 reports.

The switch uses IGMP report suppression to forward only one IGMP report per multicast router query 
to multicast devices. When IGMP router suppression is enabled (the default), the switch sends the first 
IGMP report from all hosts for a group to all the multicast routers. The switch does not send the 
remaining IGMP reports for the group to the multicast routers. This feature prevents duplicate reports 
from being sent to the multicast devices.

If the multicast router query includes requests only for IGMPv1 and IGMPv2 reports, the switch 
forwards only the first IGMPv1 or IGMPv2 report from all hosts for a group to all the multicast routers. 

If the multicast router query also includes requests for IGMPv3 reports, the switch forwards all IGMPv1, 
IGMPv2, and IGMPv3 reports for a group to the multicast devices.

If you disable IGMP report suppression, all IGMP reports are forwarded to the multicast routers. For 
configuration steps, see the 

.

IGMP snooping allows switches to examine IGMP packets and make forwarding decisions based on 
their content. These sections contain this configuration information: