Dell POWEREDGE M1000E - Manual (Page 591)

24-9
Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
OL-13270-03
Chapter 24 Configuring IGMP Snooping and MVR
Configuring IGMP Snooping
Setting the Snooping Method
Multicast-capable router ports are added to the forwarding table for every Layer 2 multicast entry. The
switch learns of such ports through one of these methods:
• Snooping on IGMP queries, Protocol-Independent Multicast (PIM) packets, and Distance Vector
Multicast Routing Protocol (DVMRP) packets
• Listening to Cisco Group Management Protocol (CGMP) packets from other routers
• Statically connecting to a multicast router port with the ip igmp snooping mrouter global
configuration command
You can configure the switch either to snoop on IGMP queries and PIM/DVMRP packets or to listen to
CGMP self-join or proxy-join packets. By default, the switch snoops on PIM/DVMRP packets on all
VLANs. To learn of multicast router ports through only CGMP packets, use the ip igmp snooping vlan
vlan-id mrouter learn cgmp global configuration command. When this command is entered, the router
listens to only CGMP self-join and CGMP proxy-join packets and to no other CGMP packets. To learn
of multicast router ports through only PIM-DVMRP packets, use the ip igmp snooping vlan vlan-id
mrouter learn pim-dvmrp global configuration command.
Note If you want to use CGMP as the learning method and no multicast routers in the VLAN are CGMP
proxy-enabled, you must enter the ip cgmp router-only command to dynamically access the router. For
more information, see
Chapter 44, “Configuring IP Multicast Routing.”
Beginning in privileged EXEC mode, follow these steps to alter the method in which a VLAN interface
dynamically accesses a multicast router:
To return to the default learning method, use the no ip igmp snooping vlan vlan-id mrouter learn cgmp
global configuration command.
This example shows how to configure IGMP snooping to use CGMP packets as the learning method:
Switch# configure terminal
Switch(config)# ip igmp snooping vlan 1 mrouter learn cgmp
Switch(config)# end
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 ip igmp snooping vlan vlan-id mrouter
learn {cgmp | pim-dvmrp} Enable IGMP snooping on a VLAN. The VLAN ID range is 1 to 1001
and 1006 to 4094.
Specify the multicast router learning method:
• cgmp—Listen for CGMP packets. This method is useful for
reducing control traffic.
• pim-dvmrp—Snoop on IGMP queries and PIM-DVMRP
packets. This is the default.
Step 3 end Return to privileged EXEC mode.
Step 4 show ip igmp snooping Verify the configuration.
Step 5 copy running-config startup-config (Optional) Save your entries in the configuration file.