Extreme Networks is leading the industry with a new approach to transporting IP multicast using IP Multicast over Fabric Connect. IP Multicast over Fabric Connect greatly simplifies multicast deployment, with no need for any multicast routing protocols such as Protocol Independent Multicast-Sparse Mode (PIM-SM) or Protocol Independent Multicast-Source Specific Multicast (PIM-SSM). A BEB can forward a multicast stream anywhere in an SPBM network where IS-IS advertises the stream to the rest of the fabric.
The advantage of this solution over traditional approaches is the simplicity in provisioning and deploying IP multicast bridging and routing. Also, due to the fact that only one control plane protocol (IS-IS) exists, convergence times in the event of a network failure, are typically sub second.
You can compare the quick convergence times for IP Multicast over Fabric Connect to Interior Gateway Protocols like Open Shortest Path First (OSPF) combined with PIM-SM or PIM-SSM. OSPF combined with PIM-SM or PIM-SSM can have recovery times that are sub optimal with convergence times that take tens of seconds. PIM experiences longer convergence times, in part, because unicast IP routing protocols must converge before PIM can converge. PIM also maintains the network state for every multicast group and uses a mechanism based on each hop to update the network about state changes, which affects scalability.
IP Multicast over Fabric Connect is extremely scalable because you only apply the multicast bridging and routing functionality at the SPBM fabric edge, with the streams mapped to SPBM multicast trees in the fabric.
IP Multicast over Fabric Connect introduces extensions to the SPBM IS-IS control plane to exchange IP multicast stream advertisement and membership information. IP Multicast over Fabric Connect uses these extensions, along with the Internet Group Management Protocol (IGMP) Snooping and Querier functions at the edge of the SPBM cloud, to create sub-trees of the VSN SPB for each multicast group to transport IP multicast data.
Layer 2 Virtual Services Network with IGMP support on the access networks for optimized forwarding of IP multicast traffic in a bridged network (Layer 2 VSN with IP Multicast over Fabric Connect). Example application: Multicast in data centers.
IP multicast routing support for IP Shortcuts using SPBM in the core and IGMP on the access (IP Shortcuts with IP Multicast over Fabric Connect). Example applications: Video surveillance, TV/Video/Ticker/Image distribution, VX-LAN.
Layer 3 Virtual Services Network with VRF based routing support for IP Multicast over Fabric Connect in the core and IGMP on the access (Layer 3 VSN with IP Multicast over Fabric Connect). Example applications: Video surveillance, TV/Video/Ticker/Image Distribution, VX-LAN, Multi-tenant IP multicast.