Bridge VLAN IGMP Snooping

IGMP is used for managing IP multicast group members. Controllers and service platforms listen to IGMP network traffic and forward IGMP multicast packets to radios on which the interested hosts are connected. On the wired side of the network, the controller or service platform floods all the wired interfaces. This feature reduces unnecessary flooding of multicast traffic in the network.

To define a profile's bridge VLAN IGMP settings:

  1. Select the IGMP Snooping tab.

  2. Define the following General parameters for the bridge VLAN configuration:

    Enable IGMP Snooping

    Select the check box to enable IGMP snooping. If disabled, snooping on a per VLAN basis is also disabled. This feature is enabled by default. If disabled, the settings under bridge configuration are overridden. For example, if IGMP snooping is disabled, but the bridge VLAN is enabled, the effective setting is disabled.

    Forward Unknown Unicast Packets

    Select the check box to enable to forward multicast packets from unregistered multicast groups. If disabled (the default setting), the unknown multicast forward feature is also disabled for individual VLANs.

    Enable Fast Leave Processing

    Select this option to remove a Layer 2 LAN interface from the IGMP snooping forwarding table entry without initially sending IGMP group-specific queries to the interface. When receiving a group specific IGMPv2 leave message, IGMP snooping removes the interface from the Layer 2 forwarding table entry for that multicast group, unless a multicast router was learned on the port. Fast-leave processing enhances bandwidth management for all hosts on the network.

    Last Member Query Count

    Specify the number of group specific queries sent before removing an IGMP snooping entry.

  3. Within the Multicast Router section, select those interfaces used as multicast router interfaces. Multiple interfaces can be selected and overridden. Set the pim-dvmrp or static Multicast Routing Learn Mode. DVMRP builds a parent-child database using a constrained multicast model to build a forwarding tree rooted at the source of the multicast packets. Multicast packets are initially flooded down this source tree. If redundant paths are on the source tree, packets are not forwarded along those paths.

  4. Set the following IGMP Querier parameters for the profile‘s bridge VLAN configuration:

    Enable IGMP Snooping

    IGMP snoop querier is used to keep host memberships alive. It‘s primarily used in a network where there‘s a multicast streaming server, hosts subscribed to the server and no IGMP querier present. An IGMP querier sends out periodic IGMP query packets. Interested hosts reply with an IGMP report packet. IGMP snooping is only conducted on wireless radios. IGMP multicast packets are flooded on wired ports. IGMP multicast packet are not flooded on the wired port. IGMP membership is also learnt on it and only if present, then it is forwarded on that port.

    Source IP Address

    Define an IP address applied as the source address in the IGMP query packet. This address is used as the default VLAN querier IP address.

    IGMP Version

    Use the spinner control to set the IGMP version compatibility to either version 1, 2 or 3. The default setting is 3.

    Maximum Response Time

    Specify the maximum time (from 1 - 25 seconds) before sending a responding report. When no reports are received from a radio, radio information is removed from the snooping table. For IGMP reports from wired ports, reports are only forwarded to the multicast router ports. The default setting is 10 seconds.

    Other Querier Timer Expiry

    Specify an interval in either Seconds (60 - 300) or Minutes (1 - 5) used as a timeout interval for other querier resources. The default setting is 1 minute.

  5. Select the OK button to save the changes to the bridge VLAN IGMP Snooping tab. Select Reset to revert to the last saved configuration.