IGMP Snooping
Table 13-4 Configure port fast-leave
Enter global configuration mode
interface ethernet
interface-num
Configure port fast-leave
By default, port fast-leave
disables
13.2.5 Configuring Number of Multicast Group
Allowed Learning
Use igmp-snooping group-limit command to configure the number of the multicast group
allowed learning.
Table 13-5 Configure the number of the multicast group allowed learning
Enter global configuration mode
interface ethernet
interface-num
Configure the number of the
multicast group allowed
learning
igmp-snooping group-limit
number
By default, the number of the
multicast group allowed learning
is NUM_MULTICAST_GROUPS
13.2.6 Configuring IGMP Snooping Querier
In an IP multicast network running IGMP, a multicast router or Layer 3 multicast switch is
responsible for sending IGMP general queries, so that all Layer 3 multicast devices can
establish and maintain multicast forwarding entries, thus to forward multicast traffic correctly
at the network layer. his router or Layer 3 switch is called IGMP querier.
However, a Layer 2 multicast switch does not support IGMP, and therefore cannot send
general queries by default. By enabling IGMP Snooping on a Layer 2 switch in a VLAN where
multicast traffic needs to be Layer-2 switched only and no multicast routers are present, the
Layer 2 switch will act as the IGMP Snooping querier to send IGMP queries, thus allowing
multicast forwarding entries to be established and maintained at the data link layer.