Users Guide

When a host receives a query, it does not respond immediately, but rather starts a delay timer. The delay time is set to a random
value between 0 and the maximum response time. The host sends a response when the timer expires; in IGMP version 2, if
another host responds before the timer expires, the timer nullifies, and no response is sent.
The querier advertises the maximum response time in the query. Lowering this value decreases leave latency but increases
response burstiness because all host membership reports are sent before the maximum response time expires. Inversely,
increasing this value decreases burstiness, but increases leave latency.
To configure maximum response time:
OS10# configure terminal
OS10# interface vlan120
OS10(conf-if-vl-120)# ip igmp query-max-resp-time 20
IGMP immediate leave
If the IGMP querier does not receive a response to a group-specific or group-and-source query, it sends another query based
on the configured querier robustness value. This value determines the number of times the querier sends the message. If the
querier does not receive a 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. Immediate leave does not send group-specific or group-and-source queries before deleting the
entry.
To configure IGMP immediate leave:
OS10# configure terminal
OS10# interface vlan14
OS10(conf-if-vl-14)# ip igmp immediate-leave
Select an IGMP version
OS10 enables IGMP version 3 by default.
If hosts require an IGMP version other than 3, use the following to select a different IGMP version:
OS10# configure terminal
OS10# interface vlan12
OS10(conf-if-vl-12)# ip igmp version 3
IGMP snooping
IGMP snooping uses the information in IGMP packets to generate a forwarding table that associates ports with multicast
groups. When switches receive multicast frames, they forward them to their intended receivers. OS10 supports IGMP snooping
on virtual local area network (VLAN) interfaces.
Effective with OS10 release 10.4.3.0, IGMP snooping is enabled by default.
NOTE:
OS10 supports IGMP snooping only with proxy reporting. OS10 does not relay the IGMP join packets received from
hosts as is. Instead, OS10 generates, bundles, and sends IGMP join packets to mrouter port based on the version of IGMP
queries received from IGMP routers. Proxy reporting reduces the number of IGMP control packets sent to the multicast
router.
Configuration notes
All Dell EMC PowerSwitches except MX-Series, S4200-Series, S5200 Series, and Z9332F-ON:
If you configure and unconfigure a static connection to a multicast router on an interface using the ip igmp snooping mrouter
interface command in VLAN mode, the router port still appears in the show ip igmp snooping mrouter vlan output. To remove
the VLAN port from the show output, configure the VLAN port again using the ip igmp snooping mrouter interface
command, and then unconfigure it using the no version of the command.
Configure IGMP snooping
Multicast
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