Optimized assignment of replication-multicast IP addresses to overlay-multicast groups

A non-transitory machine readable medium storing a program which, when executed by at least one processing unit, causes the at least one processing unit to perform a method for efficiently assigning replication-multicast network addresses to overlay-multicast groups of machines executing on a plurality of host computers of a software-defined network (SDN), the method comprising:

• receiving, by one or more controllers of the SDN from a particular source machine, (i) an overlay-multicast group network address of a particular overlay-multicast group for which the particular source machine is a source, and (ii) an overlay-multicast source network address associated with the particular source machine;
• computing, by the one or more controllers using the received overlay-multicast group network address and overlay-multicast source network address, a first replication-multicast network address for the particular overlay-multicast group;
• and
• transmitting the computed first replication-multicast network address by the one or more controllers to the particular source machine, wherein the computed first replication-multicast network address is used by the particular source machine to transmit one or more multicast data message flows to a plurality of destination machines that are members of the particular overlay-multicast group.