The l2tracemroute command is a proprietary command that allows the user to trace the multicast tree for a certain multicast flow. The user specifies source, group, and service context (either VLAN or VRF) for the multicast flow to trace.
CFM sends a multicast LTM using an internal calculation to map the source, group, and context to the corresponding target address. The LTR comes from all leaves of the multicast tree for that flow, as well as transit nodes. The target MAC used in the LTM is a combination of the data I-SID and the nickname and the packet is sent on the appropriate SPBM B-VLAN. The user can see the generated multicast tree for that flow, which includes the data I-SID and nickname.