Review the following restrictions for the IP Multicast over Fabric Connect feature.
The BEB must be the only IGMP querier in the network. If the BEB receives an IGMP query from any other device, it causes unpredictable behavior, including traffic loss.
SPBM supports IGMP Snooping on a C-VLAN, but it does not support PIM on a C-VLAN. If you enable IGMP Snooping on a C-VLAN, then its operating mode is Layer 2 VSN with IP Multicast over Fabric Connect.
SPBM supports Network Load Balancing (NLB) unicast and multicast modes. SPBM does not support NLB Multicast operation with IGMP.
Note
The NLB Multicast operation feature is not supported on all hardware platforms. For more information about feature support, see VLAN Feature Support.
You must enable SSM snoop before you configure IGMP version 3, and you must enable both ssm-snoop and snooping for IGMPv3.
For IGMP Snooping, ensure that the IGMP version used by multicast hosts and other devices in the network is either the same as the IGMP version configured on the IGMP Snooping VLAN, or that compatibility mode is enabled.
If you delete any ssm-map in a static range group, the switch deletes the entire static range group. For example, create an ssm-map for 232.122.122.122 to 232.122.122.122.128 and after that configure this same range in a static group. If you delete any ssm-map between 232.122.122.122. to 232.122.122.128, the switch deletes the entire static range group.
There can be no interaction with PIM and multicast routers on the access.
The BEB only interacts with IGMP messages and not PIM, so all multicast traffic must be drawn towards the BEB, which acts as the IGMP querier, for the stream to be announced.
You must configure static IGMP receivers on the BEB access interface facing the PIM network when the sender is on the SPBM access network and the receiver is on the PIM network. Static IGMP receivers make the PIM router accept streams and avoid a Reverse Path Forwarding (RPF) check that can change the source of the stream.
You must configure static IGMP receivers on the PIM interface facing the IP Multicast over Fabric Connect network when the sender is on the PIM network and the receiver is on the SPBM access network.
You must configure Access Control Lists (ACLs) on the BEB facing the PIM network for security.
The BEB matches a single multicast stream to a particular data I-SID. As a result there is a one-to-one mapping between the S,G to data I-SID for each BEB.
The switch does not support IP Multicast over Fabric Connect routing on inter-VSN routing interfaces.
Layer 2 VSN multicast service — Multicast traffic remains within the same Layer 2 VSN across the SPBM cloud.
Layer 3 VSN multicast service — Multicast traffic remains within the same Layer 3 VSN across the SPBM cloud.
IP Shortcuts multicast service — Multicast traffic can cross VLAN boundaries but remains confined to the subset of VLANs with the Global Routing Table that have IP Multicast over Fabric Connect enabled.