Immediate-Leave Processing; Configuring Igmp Snooping; Default Igmp Snooping Configuration - Cisco Catalyst 3750 Software Configuration Manual

Metro switch

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Configuring IGMP Snooping and MVR

Immediate-Leave Processing

The switch uses IGMP snooping Immediate-Leave processing to remove from the forwarding table an

interface that sends a leave message without the switch sending MAC-based general 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 processing 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 processing 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 be inadvertently dropped. Immediate Leave is only supported with IGMP

version 2 hosts.

IGMP snooping allows switches to examine IGMP packets and make forwarding decisions based on their

These sections describe how to configure IGMP snooping:

Table 17-3 Default IGMP Snooping Configuration

IGMP snooping

Multicast routers

Multicast router learning (snooping) method

IGMP snooping Immediate Leave

Static groups

Default IGMP Snooping Configuration, page 17-5

Enabling or Disabling IGMP Snooping, page 17-6

Setting the Snooping Method, page 17-6

Configuring a Multicast Router Port, page 17-8

Configuring a Host Statically to Join a Group, page 17-9

Enabling IGMP Immediate-Leave Processing, page 17-10

shows the default IGMP snooping configuration.

Default Setting

Enabled globally and per VLAN

None configured

None configured

Catalyst 3750 Metro Switch Software Configuration Guide