CHAPTER
20-1
Cisco ME 3400 EthernetAccess Switch SoftwareConfiguration Guide
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20
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 grou p 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 20-1
•Configuring IGMP Snooping, page 20-6
•Displaying IGMP Snooping Information, page 20-15
•Understanding Multicast VLAN Registration, page 20-16
•Configuring MVR, page 20-18
•Displaying MVR Information, page 20-22
•Configuring IGMP Filtering and Throttling, page 20-22
•Displaying IGMP Filtering and Throttling Configuration, page 20-28
Note You can either manage IP multicast group addresses through features such as IGMP snoop ing 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 Layer2 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 t rac k of mul ticas t gr oups and
member ports. When the switch receives an IGMP report from a ho st fo r a pa rti cul ar m ul tica st gr oup ,
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.