For Epipe only, the B-MACs need to be advertised. There is no multicast for PBB Epipes. Unicast traffic follows the unicast path shortest path or single tree. By configuring remote B-MACs Epipes can be setup to non-SPBM systems. A special conditional static-mac is used for SPBM PBB B-VPLS SAPs/SDPs that are connected to a remote system. In the diagram ISID 500 is used for the PBB Epipe but only conditional MACs A and B are configured on the MC-LAG ports. The B-VPLS advertises the static MAC either always or optionally based on a condition of the port forwarding.