Disabling Multicast Flooding; Specifying A Port As Connected To A Multicast Router; Configuring The Switch As Querier - Dell S4820T Configuration Manual

• View the configuration.
INTERFACE VLAN mode
show config
Example of Configuration Output After Removing a Group-Port Association
Dell(conf-if-vl-100)#show config
!
interface Vlan 100
no ip address
ip igmp snooping fast-leave
shutdown
Dell(conf-if-vl-100)#

Disabling Multicast Flooding

If the switch receives a multicast packet that has an IP address of a group it has not learned (unregistered
frame), the switch floods that packet out of all ports on the VLAN.
When you configure the no ip igmp snooping flood command, the system drops the packets
immediately. The system does not forward the frames on mrouter ports, even if they are present. Disable
Layer 3 multicast (no ip multicast-routing) in order to disable multicast flooding.
• Configure the switch to only forward unregistered packets to ports on a VLAN that are connected to
mrouter ports.
CONFIGURATION mode
no ip igmp snooping flood

Specifying a Port as Connected to a Multicast Router

To statically specify or view a port in a VLAN, use the following commands.
• Statically specify a port in a VLAN as connected to a multicast router.
INTERFACE VLAN mode
ip igmp snooping mrouter
• View the ports that are connected to multicast routers.
EXEC Privilege mode.
show ip igmp snooping mrouter

Configuring the Switch as Querier

To configure the switch as a querier, use the following command.
Hosts that do not support unsolicited reporting wait for a general query before sending a membership
report. When the multicast source and receivers are in the same VLAN, multicast traffic is not routed and
so there is no querier. Configure the switch to be the querier for a VLAN so that hosts send membership
reports and the switch can generate a forwarding table by snooping.
• Configure the switch to be the querier for a VLAN by first assigning an IP address to the VLAN
interface.
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Internet Group Management Protocol (IGMP)