Cisco 2950G 24 Software Configuration Guide - Page 391

17 C H A P T E R Configuring IGMP Snooping and MVR This chapter describes how to configure Internet Group Management Protocol (IGMP) snooping on your 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. Note For complete syntax and usage information for the commands used in this chapter, refer to the switch command reference for this release and the Cisco IOS Release Network Protocols Command Reference, Part 1, for Release 12.1. This chapter consists of these sections: • Understanding IGMP Snooping, page 17-1 • Configuring IGMP Snooping, page 17-5 • Displaying IGMP Snooping Information, page 17-11 • Understanding Multicast VLAN Registration, page 17-13 • Configuring MVR, page 17-15 • Displaying MVR Information, page 17-19 • Configuring IGMP Filtering, page 17-20 • Displaying IGMP Filtering Configuration, page 17-24 Note For MAC addresses that map to IP multicast groups, you can either manage them through features such as IGMP snooping and MVR, or you can use static MAC addresses. However, you cannot use both methods simultaneously. Therefore, before using IGMP snooping or MVR, you should remove all statically configured MAC addresses that map to IP multicast groups. Understanding IGMP Snooping Layer 2 switches can use IGMP snooping to constrain the flooding ofmulticast 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, 78-14982-01 Catalyst 2950 Desktop Switch Software Configuration Guide 17-1