Immediate Leave; Igmp Report Suppression - Cisco Catalyst 3560-X Software Configuration Manual
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Also See for Catalyst 3560-X:
- Command reference manual (1188 pages) ,
- Software configuration manual (1438 pages) ,
- Manual (276 pages)
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Understanding IGMP Snooping
Immediate Leave
Immediate Leave is only supported on IGMP Version 2 hosts.
The switch uses IGMP snooping Immediate Leave to remove from the forwarding table an interface that
sends a leave message without the switch sending group-specific queries to the interface. The VLAN
interface is pruned from the multicast tree for the multicast group specified in the original leave message.
Immediate Leave ensures optimal bandwidth management for all hosts on a switched network, even
when multiple multicast groups are simultaneously in use.
You should only use the Immediate Leave feature on VLANs where a single host is connected to each
Note
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
IGMP Configurable-Leave Timer
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
Note
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
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
1-6
"Enabling IGMP Immediate Leave" section on page
"Configuring the IGMP Leave Timer" section on page
"Disabling IGMP Report Suppression" section on page
Chapter 1
Configuring IGMP Snooping and MVR
1-11.
1-11.
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Troubleshooting
