Chapter 15 Configuring Multicast Services; Understanding How Multicasting Works; Understanding Multicasting And Multicast Services Operation - Cisco WS-C2948G-GE-TX Configuration Manual

Configuring Multicast Services
This chapter describes how to configure multicast services, including Cisco Group Management
Protocol (CGMP), Internet Group Management Protocol (IGMP) snooping, and GARP Multicast
Registration Protocol (GMRP) on the Catalyst enterprise LAN switches.
For complete syntax and usage information for the commands that are used in this chapter, refer to the
Note
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Command
Reference.
This chapter consists of these sections:
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Understanding How Multicasting Works

The following sections describe how multicasting works on the Catalyst enterprise LAN switches.

Understanding Multicasting and Multicast Services Operation

CGMP, IGMP snooping, and GMRP manage multicast traffic in switches by allowing directed switching
of IP multicast traffic. Switches can use CGMP, IGMP snooping, or GMRP to dynamically configure
switch ports so that IP multicast traffic is forwarded only to ports that are associated with IP multicast
hosts.
For more information on IP multicast and IGMP, refer to RFC 1112. GMRP is described in IEEE 802.1p.
Note
CGMP and IGMP software components run on the Cisco router and the switch. A CGMP/IGMP-capable
IP multicast router sees all IGMP packets and can inform the switch when specific hosts join or leave IP
multicast groups.
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
78-15908-01
Understanding How Multicasting Works, page 15-1
Configuring CGMP, page 15-4
Configuring GMRP, page 15-9
Configuring Multicast Router Ports and Group Entries, page 15-15
Filtering IGMP Traffic, page 15-17
C H A P T E R
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