It also enables users, remotely located across one or more circuit switched networks, to access services offered by {TAIL ~ one or more machines} situated on {HEAD ~ one or more heterogeneous local networks} 
It also enables users , remotely located across one or more circuit switched networks , to access services offered by { TAIL ~ one or more machines } situated on { HEAD ~ one or more heterogeneous local networks }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD