Multicast Subnets for the Management NetworkΒΆ

A multicast subnet specifies the range of addresses that the system can use for multicast messaging on the network. You can use this subnet to prevent multicast leaks in multi-region environments. Addresses for the affected services are allocated automatically from the subnet.

The requirements for multicast subnets are as follows:

  • IP multicast addresses must be in the range of through

    For IPv6, the recommended range is ffx5::/16.

  • IP multicast address ranges for a particular region must not conflict or overlap with the IP multicast address ranges of other regions.

  • IP multicast address ranges must not conflict or overlap with the well-known multicast addresses listed at:

  • IP multicast addresses must be unique within the network.

  • The lower 23-bits of the IP multicast address, used to construct the multicast MAC address, must be unique within the network.

  • When interfaces of different regions are on the same L2 network / IP subnet, a separate multicast subnet is required for each region.

  • The minimum multicast network range is 16 host entries.


Addresses used within the IP multicast address range apply to services using IP multicast, not to hosts.


ToR switches with snooping enabled on this network segment require a IGMP/MLD querier on that network to prevent nodes from being dropped from the multicast group.

The default setting for the multicast subnet is The default for IPv6 is ff05::14:1:1:0/124.