Multimedia Traffic Control with IP Multicast (IGMP) 
CLI: Configuring and Displaying IGMP 
Note s  Whenever IGMP is enabled, the switch generates an Event Log message 
indicating whether querier functionality is enabled. 
IP multicast traffic groups are identified by IP addresses in the range of 
224.0.0.0 to 239.255.255.255. Also, incoming IGMP packets intended for 
reserved, or “well-known” multicast addresses automatically flood through all 
ports (except the port on which the packets entered the switch). For more on 
this topic, see 
“Excluding Well-Known or Reserved Multicast Addresses from 
IP Multicast Filtering” on page 4-20. 
For more information, refer to “How IGMP Operates” on page 4-11. 
CLI: Configuring and Displaying IGMP 
IGMP Commands Used in This Section 
show ip igmp configuration 
ip igmp 
high-priority-forward 
auto <[ethernet] <port-list> 
blocked <[ethernet] <port-list> 
forward <[ethernet] <port-list> 
querier 
show ip igmp 
page 4-7 
page 4-8 
page 4-10 
page 4-9 
page 4-9 
page 4-9 
page 4-10 
Refer to the section titled “Internet Group 
Management Protocol (IGMP) Status” in appendix B 
of the Management and Configuration Guide for your 
switch. 
Note for 3400cl and  IGMP and ACLs share resources. If ACLs use up all allotted masks, then IGMP 
6400cl Switches 
cannot be configured on the switch. Conversely, configuring IGMP on any 
VLAN uses one mask resource on all switch ports, which reduces by 1 the 
mumber of masks available for ACL configuration. 
4-6