Configuration notes and feature limitations for IGMP snooping and Layer 3 multicast routing
The following notes apply to all devices:
- Layer 2 IGMP multicast is automatically enabled with Layer 3 multicast routing. If Layer 3 multicast routing is enabled on your system, do not attempt to enable Layer 2 IGMP snooping.
- The default IGMP version is V2.
- A user can configure the maximum numbers of group address entries.
- An IGMP device can be configured to rate-limit the forwarding IGMP V2 membership reports to queriers.
- The device supports static groups. The device acts as a proxy to send IGMP reports for the static groups when receiving queries.
- A user can configure static router ports to force all multicast traffic to these specific ports.
- If a VLAN has a connection to a PIM-enabled port on another router, the VLAN must be configured as a non-querier (passive). When multiple snooping devices connect together and there is no connection to PIM ports, one device must be configured as a querier (active). If multiple devices are configured as active (queriers), only one will keep sending queries after exchanging queries.
- The querier must configure an IP address to send out queries.
- IGMP snooping requires hardware resource. Hardware resource is installed only when there is data traffic. If resource is inadequate, the data stream without a resource is mirrored to the CPU in addition to being VLAN flooded, which can cause high CPU usage. Brocade recommends that you avoid global enabling of snooping unless necessary.
- IGMP snooping requires clients to send membership reports in order to receive data traffic. If a client application does not send reports, you must configure static groups on the snooping VLAN to force traffic to client ports. Note that servers (traffic sources) are not required to send IGMP memberships.
- Support for VSRP together with IGMP snooping on the same interface.
- When VSRP or VSRP-aware is configured on a VLAN, only IGMP version 2 is recommended; IGMP version 3 is not recommended.
- Each VLAN can independently enable or disable IGMP, or configure IGMP v2 or IGMP v3.
- IGMP/PIM-SM snooping over Multi-Chassis Trunking is supported on ICX devices.