Administrator Guide

Layer 2 Switching Commands 484
The VLAN IP address takes precedence over the global IP address when both
are configured. IGMP Querier does not detect when the local switch is
configured as a multicast router. It is not recommended to configure both L3
multicast routing and IGMP Querier on the same switch.
IGMP snooping (and IGMP querier) validates IGMP packets. As part of the
validation, IGMP checks for the router alert option. If other devices in the
network do not send IGMP packets with the router alert option, IGMP
snooping (and snoooping querier) will discard the packet. Use the no ip igmp
snooping router-alert-check command to disable checking for the router alert
option.
Example
The following example enables IGMP snooping querier in Global
Configuration mode.
console(config)#ip igmp snooping querier vlan 1 address 10.19.67.1
ip igmp snooping querier election participate
This command enables the Snooping Querier to participate in the Querier
Election process when it discovers the presence of another Snooping Querier
in the VLAN. When election mode is enabled, if the Snooping Querier finds
that the other Querier source address is numerically higher than the
Snooping Querier address, it stops sending periodic queries. The Snooping
Querier with the numerically lower IP address wins the election, and
continues sending periodic queries. The no form of this command sets the
snooping querier not to participate in the querier election but to stop sending
queries as soon as it discovers the presence of another querier in the VLAN.
Syntax
ip igmp snooping querier election participate vlan-id
no ip igmp snooping querier election participate vlan-id
Parameters
• vlan-id —The VLAN identifier on which the querier is expected to operate.
Range 1-4093.
2CSNXXX_SWUM204.book Page 484 Monday, January 25, 2016 1:25 PM