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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter24 Configuring IP Multicast Routing
Cisco Implementation of IP Multicast Routing
Configuring Basic DVMRP Interoperability Features, page 24-43
Configuring Advanced DVMRP Interoperability Features, page 24-50
Monitoring and Maintaining IP Multicast Routing, page 24-57
For information on configuring the Multicast Source Discovery Protocol (MSDP), see Chapter 25,
Configuring MSDP.
Note When you are configuring multicast routing parameters for the switch, to allocate system resources
to maximize the number of possible multicast routes allowed, you can use the sdm prefer routing
global configuration command to set the Switch Database Management feature to the routing
template. For more information on the SDM templates, see the Optimizing System Resources for
User-Selected Features section on page6-57.
Cisco Implementation of IP Multicast Routing
The Cisco IOS software supports these protocols to implement IP multicast routing:
Internet Group Management Protocol (IGMP) is used among hosts o n a LA N a nd the rout ers (and
multilayer switches) on that LAN to track the multicast groups of which hosts are members.
Protocol-Independent Multicast (PIM) protocol is used among routers and multilayer switches to
track which multicast packets to forward to each other and to their directly connected LANs.
Distance Vector Multicast Routing Protocol (DVMRP) is used on the multicast backbone of the
Internet (MBONE). The Cisco IOS software supports PIM-to-DVMRP interaction.
Cisco Group Management Protocol (CGMP) is used on Cisco router s and m ult ilaye r sw itche s
connected to Layer 2 Catalyst switches to perform tasks similar to those performed by IGMP.
Figure 24-1 shows where these protocols operate within the IP multicast environment.
Figure24-1 IP Multicast Routing Protocols
Host
Host
PIM
IGMP
CGMP
DVMRP
Internet
MBONE
Cisco Catalyst switch
(CGMP client)
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