NSX Data Center 6.4.2 and later supports multicast routing.

NSX uses two multicast routing protocols: Internet Group Management Protocol (IGMPv2) and Protocol Independent Multicast (PIM). PIM sparse mode is supported (PIM-SM). PIM is used on ESGs, but not on the DLR.

  • Multicast routing is supported between the ESG and the DLR.
  • Receiving hosts advertise their group membership to a local multicast router, enabling them to join and leave multicast groups.
  • Protocol-Independent Multicast (PIM) is used for a router-to-router signaling. It maintains the current IP multicast service mode of receiver-initiated membership.

After any routing protocol is first enabled (or disabled and re-enabled), traffic is not forwarded until the protocol has converged, and the routes corresponding to the traffic have been learned and installed. In a multicast network, traffic forwarding requires both the unicast and the multicast routing protocols to converge. PIM Sparse-mode also requires that the Rendezvous Point (RP) for a multicast group is known before any control or data traffic for the multicast group is processed. When the PIM Bootstrap mechanism is used to disseminate the RP information, the Candidate RPs are learned only after a Bootstrap message from a PIM neighbor is received. These messages have an RFC default periodicity of 60 secs. If a Static RP is configured, the RP information is available immediately and the delay associated with the Bootstrap mechanism is avoided.

Support and Limitations:
  • IPv4 support.
  • IGMPv2 support.
  • PIM Sparse mode is supported.
  • Rendezvous point information can be delivered through bootstrap messages, or statically configured.
  • Replication Multicast Range should not overlap with a Transport Zone multicast range.
  • An Edge Services Gateway (ESG) cannot be a Bootstrap Candidate Router.
  • An ESG cannot be the Rendezvous Point (RP).
  • During vMotion of virtual machines that are receivers of multicast, a 1–2 second multicast traffic loss can occur.
Topologies:
  • In a Cross-VC environment, connecting two Edge Services Gateways with multicast to the same universal TLS is not supported.
  • Single tier of Edge Services Gateway only.
  • Single distributed logical router, that is, only one downlink on ESG.
  • In NSX 6.4.5 or later, multicast is supported on a maximum of two uplink interfaces and one downlink interface per ESG. However, if an NSX Edge is at 6.4.4 or earlier, multicast is supported on a single uplink interface and a single downlink interface per ESG.
  • On a DLR, multicast is supported on a single uplink interface and on multiple internal interfaces.
  • Active-standby high availability is supported by enabling ESG HA. Active-active high availability using ECMP is not supported.
  • High availability failover time of 30 seconds.
  • Cold standby, no sync of mroutes or mFIB.
  • L2 bridging is not supported on a logical switch with multicast routing.
  • Hardware VTEP gateways (ToR gateways) are not supported on a logical switch with multicast routing.