Configuring Igmp Snooping; Default Igmp Snooping Configuration; Enabling Or Disabling Igmp Snooping - Cisco 2950G 24 - Catalyst Switch Software Configuration Manual

Chapter 17 Configuring IGMP Snooping and MVR
Note 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 supported with only IGMP
version 2 hosts.

Configuring IGMP Snooping

IGMP snooping allows switches to examine IGMP packets and make forwarding decisions based on
their content.
These sections describe how to configure IGMP snooping:
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Default IGMP Snooping Configuration

Table 17-3
Table 17-3 Default IGMP Snooping Configuration
Feature
IGMP snooping
Multicast routers
Multicast router learning (snooping) method
IGMP snooping Immediate Leave
Static groups
IP multicast-source-only learning

Enabling or Disabling IGMP Snooping

By default, IGMP snooping is globally enabled on the switch. When globally enabled or disabled, it is
also enabled or disabled in all existing VLAN interfaces. IGMP snooping is by default enabled on all
VLANs, but can be enabled and disabled on a per-VLAN basis.
Global IGMP snooping overrides the VLAN IGMP snooping. If global snooping is disabled, you cannot
enable VLAN snooping. If global snooping is enabled, you can enable or disable VLAN snooping.
78-14982-01
Default IGMP Snooping Configuration, page 17-5
Enabling or Disabling IGMP Snooping, page 17-5
Setting the Snooping Method, page 17-6
Configuring a Multicast Router Port, page 17-7
Configuring a Host Statically to Join a Group, page 17-8
Enabling IGMP Immediate-Leave Processing, page 17-9
Disabling IP Multicast-Source-Only Learning, page 17-9
shows the default IGMP snooping configuration.
Default Setting
Enabled globally and per VLAN
None configured
PIM-DVMRP
Disabled
None configured
Enabled
Catalyst 2950 Desktop Switch Software Configuration Guide
Configuring IGMP Snooping
17-5