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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
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Configuring IGMP Snooping and MVR
This chapter describes how to configure Internet Group Management Protocol (IGMP) snooping on the
Cisco ME 3400 Ethernet Access switch, including an application of local IGMP snooping, Multicast
VLAN Registration (MVR). It also includes procedures for controlling multicast group membership by
using IGMP filtering and procedures for configuring the IGMP throttling action.
Note For complete syntax and usage information for the commands used in this chapter, see the switch
command reference for this release and the “IP Multicast Routing Commands” section in the Cisco IOS
IP Command Reference, Volume 3 of 3:Multicast, Release 12.2.
This chapter consists of these sections:
• Understanding IGMP Snooping, page 21-1
• Configuring IGMP Snooping, page 21-6
• Displaying IGMP Snooping Information, page 21-14
• Understanding Multicast VLAN Registration, page 21-15
• Configuring MVR, page 21-18
• Displaying MVR Information, page 21-23
• Configuring IGMP Filtering and Throttling, page 21-23
• Displaying IGMP Filtering and Throttling Configuration, page 21-29
Note You can either manage IP multicast group addresses through features such as IGMP snooping and MVR,
or you can use static IP addresses.

Understanding IGMP Snooping

Layer 2 switches can use IGMP snooping to constrain the flooding of multicast traffic by dynamically
configuring Layer 2 interfaces so that multicast traffic is forwarded to only those interfaces associated
with IP multicast devices. As the name implies, IGMP snooping requires the LAN switch to snoop on
the IGMP transmissions between the host and the router and to keep track of multicast groups and
member ports. When the switch receives an IGMP report from a host for a particular multicast group,
the switch adds the host port number to the forwarding table entry; when it receives an IGMP Leave
Group message from a host, it removes the host port from the table entry. It also periodically deletes
entries if it does not receive IGMP membership reports from the multicast clients.