Enabling Igmp Immediate-Leave; Igmp Snooping; Igmp Snooping Implementation Information - Dell S4048T Configuration Manual

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Enabling IGMP Immediate-Leave

If the querier does not receive a response to a group-specific or group-and-source query, it sends another
(querier robustness value). Then, after no response, it removes the group from the outgoing interface for the
subnet.
IGMP immediate leave reduces leave latency by enabling a router to immediately delete the group
membership on an interface after receiving a Leave message (it does not send any group-specific or group-
and-source queries before deleting the entry).
• Configure the system for IGMP immediate leave.
ip igmp immediate-leave
• View the enable status of the IGMP immediate leave feature.
EXEC Privilege mode
show ip igmp interface
View the enable status of this feature using the command from EXEC Privilege mode, as shown in the
example in Selecting an IGMP

IGMP Snooping

IGMP snooping enables switches to use information in IGMP packets to generate a forwarding table that
associates ports with multicast groups so that when they receive multicast frames, they can forward them
only to interested receivers.
Multicast packets are addressed with multicast MAC addresses, which represent a group of devices, rather
than one unique device. Switches forward multicast frames out of all ports in a virtual local area network
(VLAN) by default, even though there may be only some interested hosts, which is a waste of bandwidth.
If you enable IGMP snooping on a VLT unit, IGMP snooping dynamically learned groups and multicast router
ports are made to learn on the peer by explicitly tunneling the received IGMP control packets.

IGMP Snooping Implementation Information

• IGMP snooping on Dell Networking OS uses IP multicast addresses not MAC addresses.
• IGMP snooping is supported on all stack members.
• IGMP snooping reacts to spanning tree protocol (STP) and multiple spanning tree protocol (MSTP)
topology changes by sending a general query on the interface that transitions to the forwarding state.
ip pim sparse-mode
ip address 10.11.4.1/24
untagged TenGigabitEthernet 1/2
ip igmp access-group igmpjoinfilR2G2
no shutdown
Version.
Internet Group Management Protocol (IGMP) 437