If multicast loopback is disabled (this value is set to 1), then when sending multicast packets, RTI Connext will not put a copy of the packets on the loopback interface. This prevents applications on the same node (including itself) from receiving those packets.

This value is set to 0 by default, meaning multicast loopback is enabled.

Disabling multicast loopback (setting this value to 1) may result in minor performance gains when using multicast.