Deployment Guide

IGMP Snooping Commands
Dell EMC Networking OS supports IGMP Snooping version 2 and 3 on all Dell EMC Networking systems.
Important Points to Remember for IGMP Snooping
● Dell EMC Networking OS supports version 1, version 2, and version 3 hosts.
● Dell EMC Networking OS IGMP snooping implementation is based on IP multicast address (not based on Layer 2 multicast
mac address) and the IGMP snooping entries are in Layer 3 flow table not in Layer 2 forwarding information base (FIB).
● Dell EMC Networking OS IGMP snooping implementation is based on draft-ietf-magma-snoop-10.
● Dell EMC Networking OS supports IGMP snooping on JUMBO-enabled cards.
● IGMP snooping is not enabled by default on the switch.
● A maximum of 1800 groups and 600 VLAN are supported.
● IGMP snooping is not supported on a default VLAN interface.
● IGMP snooping is not supported over VLAN-Stack-enabled VLAN interfaces (you must disable IGMP snooping on a VLAN
interface before configuring VLAN-Stack-related commands).
● IGMP snooping does not react to Layer 2 topology changes triggered by spanning tree protocol (STP).
● IGMP snooping reacts to Layer 2 topology changes multiple spanning tree protocol (MSTP) triggers by sending a general
query on the interface that comes in the FWD state.
Important Points to Remember for IGMP Querier
● The IGMP snooping Querier supports version 2.
● You must configure an IP address to the VLAN interface for IGMP snooping Querier to begin. The IGMP snooping Querier
disables itself when a VLAN IP address is cleared, and then it restarts itself when an IP address is reassigned to the VLAN
interface.
● When enabled, IGMP snooping Querier does not start if there is a statically configured multicast router interface in the
VLAN.
● When enabled, IGMP snooping Querier starts after one query interval in case no IGMP general query (with IP SA lower than
its VLAN IP address) is received on any of its VLAN members.
● When enabled, IGMP snooping Querier periodically sends general queries with an IP source address of the VLAN interface. If
it receives a general query on any of its VLAN member, it checks the IP source address of the incoming frame.
If the IP SA in the incoming IGMP general query frame is lower than the IP address of the VLAN interface, the switch
disables its IGMP snooping Querier functionality.
If the IP SA of the incoming IGMP general query is higher than the VLAN IP address, the switch continues to work as an
IGMP snooping Querier.
clear ip igmp snooping groups
Clear snooping entries from the group cache table.
Syntax
clear ip igmp snooping groups [group-address interface | interface]
Parameters
group-address (OPTIONAL) Enter the IP multicast group address in dotted decimal format.
interface
interface
Enter the following keywords and the interface information:
● For a 10-Gigabit Ethernet interface, enter the keyword
TenGigabitEthernet then the slot/port/subport information.
● For a 25-Gigabit Ethernet interface, enter the keyword twentyFiveGigE
then the slot/port/subport information.
● For a 40-Gigabit Ethernet interface, enter the keyword fortyGigE then the
slot/port/subport information.
636 Internet Group Management Protocol (IGMP)