{HEAD ~ A hierarchical version} including multiple star couplers and {TAIL ~ selection devices} is also disclosed, to handle a relatively large number of stations 
including
{ HEAD ~ A hierarchical version } including multiple star couplers and { TAIL ~ selection devices } is also disclosed , to handle a relatively large number of stations
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH