31.3.6 Multi-homed use

(1) Selection of representative querier

When using IGMP snooping in a multi-homed VLAN, select a representative querier for each network. When IGMP querier function is enabled in the multi-homed VLAN, the Switch sends IGMP Query messages periodically to the representative querier's network.

(2) Enabling IGMP Querier Function

If you receive a IGMPv2 Leave message or a IGMPv3 Report message on a multihomed VLAN, enable IGMP Querier feature so that you can check the presence of group members for all networks. However, the Switch does not need to be a representative querier.

(3) Entry timeout period

When you register an entry in a multihomed VLAN, the entry timeout period is the longest timeout period in the applicable VLAN's networking.

Notes

The timeout period is calculated in Query IntervalNGRobustness Variable+Query Response Interval(10 seconds).

Query Interval and Robustness Variable are as follows:

• When another device is a representative querier and is operating in IGMPv3.

  Query Interval:IGMPv3 Query messaging QQIC field-value

  Robustness Variable:IGMPv3 Query messaging QRV field-value

• When the local device operates in IGMPv3 with the representative querier or in IGMPv2.

  Query Interval:125 seconds

  Robustness Variable:2