TRILL facilitates loop free connectivity to non-TRILL legacy networks via choice of an Appointed Forwarder for a set of VLANs. Appointed Forwarder provides load sharing based on VLAN with an active-standby model. Mission critical operations such as High Performance Data Centers require active-active load sharing model. Active-Active load sharing model can be accomplished by representing any given non-TRILL legacy network with a single virtual RBridge. Virtual representation of the non-TRILL legacy network with a single RBridge poses serious challenges in multi-destination RPF (Reverse Path Forwarding) check calculations. This document specifies required enhancements to build Coordinated Multicast Trees (CMT) within the TRILL campus to solve related RPF issues. CMT provides flexibility to RBridges in selecting desired path of association to a given TRILL multi-destination distribution tree.