In one embodiment, messages may be sent only to {HEAD ~ the one or more endpoints} bound to {TAIL ~ the pipe} 
In bound
In one embodiment , messages may be sent only to { HEAD ~ the one or more endpoints } bound to { TAIL ~ the pipe }
REL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH TAIL TAIL TAIL TAIL TAIL TAIL