Flowire IGMP Settings

These settings are important to consider for multi-endpoint Flowire clusters.

IGMP querier

In order to secure the reliability of multicast handling in Flowire clusters, the network should have an active "IGMP querier".

If the core network is an unmanaged switch with no IGMP querier, it is possible to enable an "IGMP querier" in Flowire. The setting is in the Flowire web, and activates an IGMPv3 querier. It is recommended to enable "IGMP querier" in the network-side Flowire.

If the core network has an IGMP querier, do not enable "IGMP querier" in any of the Flowires.

IGMPv2 compatibility

Current versions of Cisco industrial switches only handle IGMPv2. Therefore the Cisco switch should be the IGMP querier, forcing the system to IGMPv2 reporting.

In systems where the network has a IGMPv2 querier, and there are several endpoints in the cluster, the "IGMPv2 compatibility mode" must be enabled. This setting is available in Flowire SW version 4.1.3.10 and later.

"IGMPv2 compatibility mode" must be enabled in the web on endpoint-side Flowires. It must not be set on network side Flowires! Do not enable "IGMP querier" in any of the Flowires.

If "IGMPv2 compatibility mode" is not set in an IGMPv2 network, then endpoint randomly loose multicast membership for periods of time. Both the DIP control message multicast and audio multicasts are affected. These problems are due to unfortunate design of the IGMPv2/IGMPv1 protocol itself, problems which are solved in IGMPv3. Issue AL-2720 explains the details.