C H A P T E; Configuring Igmp Snooping; Information About Igmp Snooping - Cisco Nexus 3000 Series Configuration Manual

Configuring IGMP Snooping

This chapter contains the following sections:
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Information About IGMP Snooping

The IGMP snooping software examines IGMP protocol messages within a VLAN to discover which interfaces
are connected to hosts or other devices interested in receiving this traffic. Using the interface information,
IGMP snooping can reduce bandwidth consumption in a multiaccess LAN environment to avoid flooding the
entire VLAN. The IGMP snooping feature tracks which ports are attached to multicast-capable routers to help
it manage the forwarding of IGMP membership reports. The IGMP snooping software responds to topology
change notifications.
IGMP snooping is supported on all Ethernet interfaces. The term snooping is used because Layer 3 control
Note
plane packets are intercepted and influence Layer 2 forwarding decisions.
Cisco NX-OS supports IGMPv2 and IGMPv3. IGMPv2 supports IGMPv1, and IGMPv3 supports IGMPv2.
Although not all features of an earlier version of IGMP are supported, the features related to membership
query and membership report messages are supported for all IGMP versions.
OL-29545-03
Information About IGMP Snooping, page 135
Configuring IGMP Snooping Parameters, page 138
Verifying the IGMP Snooping Configuration, page 140
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