Enabling The Igmp Snooping Querier; Configuring Parameters For Igmp Queries And Responses - HP FlexFabric 5700 Series Configuration Manual

Determine the IGMP last member query interval.
•
• Determine the maximum response time for IGMP general queries.

Enabling the IGMP snooping querier

This feature enables the switch to periodically send IGMP general queries to establish and maintain
multicast forwarding entries at the data link Layer. You can configure an IGMP snooping querier on a
network without Layer 3 multicast devices.
Configuration guidelines
When you enable the IGMP snooping querier, follow these guidelines:
Do not enable the IGMP snooping querier on a multicast network that runs IGMP. An IGMP
•
snooping querier does not take part in IGMP querier elections. However, it might affect IGMP
querier elections if it sends IGMP general queries with a low source IP address.
On a TRILL network, if an RB acts as both the IGMP snooping querier and the AVF of a VLAN, HP
•
recommends that you configure the designated port as a static router port. Otherwise, IGMP
snooping forwarding entries cannot be created. For more information about TRILL, RB, AVF, and
designated ports, see TRILL Configuration Guide.
Configuration procedure
To enable the IGMP snooping querier for a VLAN:
Step
1. Enter system view.
2. Enter VLAN view.
3. Enable the IGMP snooping
querier.

Configuring parameters for IGMP queries and responses

CAUTION:
Make sure the IGMP general query interval is larger than the maximum response time for IGMP general
queries. Otherwise, multicast group members might be mistakenly deleted.
You can modify the IGMP general query interval based on the actual condition of the network.
A receiver host starts a timer for each multicast group that it has joined when it receives an IGMP query
(general query or group-specific query). This timer is initialized to a random value in the range of 0 to the
maximum response time advertised in the IGMP query. When the timer value decreases to 0, the host
sends an IGMP report to the multicast group.
To speed up the response of hosts to IGMP queries and to avoid simultaneous timer expirations which
cause IGMP report traffic bursts, you must correctly set the maximum response time.
• The maximum response time for IGMP general queries is set by the max-response-time command.
The maximum response time for IGMP group-specific queries equals the IGMP last member query
•
interval, which is set by the last-member-query-interval interval command.
Command
system-view
vlan vlan-id
igmp-snooping querier
24
Remarks
N/A
N/A
By default, IGMP snooping querier
is disabled.