The Internet Group Management Protocol (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.
| Field | Description |
|---|---|
| Snooping | Select this option to enable IGMP snooping. If grayed out, snooping on a per VLAN basis is also turned off. This feature is selected by default. If not selected, the settings under the bridge configuration are overridden. For example, if IGMP snooping is not selected, but the bridge VLAN is enabled, the effective setting is not enabled |
| Forward unknown multicast packets | Select this option to enable the forwarding of multicast packets from unregistered multicast groups. If grayed out, the unknown multicast forward feature is also not selected for individual VLANs. This setting is enabled by default |
| Fast leave | Select this option to remove a layer 2 LAN interface from IGMP snooping 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 |
| Enable Querier | Select this option to enable IGMP querier. IGMP snoop querier is used to keep host memberships alive. It's primarily used in a network where there's a multicast streaming server and 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 |
| Version | Type the version to set the IGMP version compatibility to either version 1, 2, or 3. IGMPv1 is defined by RFC 1112, IGMPv2 is defined by RFC 2236, and IGMPv3 defined by RFC 4604 which defines both IGMPv3 and MLDv2. IGMPv2 improves over IGMPv1 by adding the ability for a host to signal desire to leave a multicast group. IGMPv3 improves over IGMPv2 by adding the ability to listen to multicast traffic originating from a set of source IP addresses exclusively. The default setting is 3 |
| Query interval | Set the interval IGMP queries are made. This parameter is used only when the querier functionality is enabled. Define an interval value in seconds (1 to 18,000). The default setting is 60 seconds |
| Robustness variable | Sets the IGMP robustness variable. The robustness variable is a way of indicating how susceptible the subnet is to lost packets. IGMP can recover from robustness variable minus 1 lost IGMP packets. Define a robustness variable from 1 to 7. The default robustness value is 2 |
| Maximum response time | Specify the maximum interval (from 1 to 25 seconds) before sending a responding report. When no reports are received from a radio, radio information is removed from the snooping table. Only multicast packets are forwarded to radios present in the snooping table. For IGMP reports from wired ports, the controller or service platform forwards these reports to the multicast router ports. The default setting is 10 seconds |
| Timer expiry | Specify an interval in seconds (60 to 300) used as a timeout interval for other querier resources. The default setting is 60 seconds |
MLD snooping caps the flooding of IPv6 multicast traffic on controller, service platform or access point VLANs. When enabled, MLD messages are examined between hosts and multicast routers and to discern which hosts are receiving multicast group traffic. The controller, service platform, or access point then forwards multicast traffic only to those interfaces connected to interested receivers instead of flooding traffic to all interfaces.
| Field | Description |
|---|---|
| Snopping | Enable MLD snooping to examine MLD packets and make content forwarding for this profile. Packets delivered to group members are identified by a single multicast group address. Multicast packets are delivered to a group using best effort reliability, just like IPv6 unicast. MLD snooping is not selected by default |
| Forward unknown multicast packets | Select this option to either enable or clear IPv6 unknown multicast forwarding. This setting is enabled by default |
| Enable Querier | Select this option to enable MLD querier on the controller, service platform, or access point. When enabled, the device sends query messages to discover which network devices are members of a given multicast group. This setting is not selected by default |
| Version | Define whether MLD version 1 or 2 is utilized as the MLD querier. MLD version 1 is based on IGMP version 2 for IPv4. MLD version 2 is based on IGMP version 3 for IPv4 and is fully backward compatible. IPv6 multicast uses MLD version 2. The default MLD version is 2 |
| Query interval | Set the interval in which query messages are sent to discover device multicast group memberships. Set an interval in seconds (1 to 18,000). The default interval is 60 seconds |
| Robustness variable | Set a MLD IGMP robustness value (1 to 7) used by the sender of a query. The MLD robustness variable enables refinements to account for expected packet loss on a subnet. Increasing the robust count allows for more packet loss, but increases the leave latency of the subnetwork unless the value is zero. The default variable is 2 |
| Maximum response time | Specify the maximum response time (from 1 to 25,000 seconds) before sending a responding report. Queriers use MLD reports to join and leave multicast groups and receive group traffic. The default setting is 10 seconds |
| Timer expiry | Specify an interval in seconds (60 - 300) used as a timeout interval for other querier resources. The default setting is 60 seconds |