{HEAD ~ A network} includes a source of multicast packets in a multicast session and {TAIL ~ a plurality} of multicast recipients in that session 
includes
{ HEAD ~ A network } includes a source of multicast packets in a multicast session and { TAIL ~ a plurality } of multicast recipients in that session
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH