In some alternative embodiments, {HEAD ~ terminal 501 m} might communicate via other means with {TAIL ~ content terminal 502 n} 
In some alternative embodiments , { HEAD ~ terminal 501 m } might communicate via other means with { TAIL ~ content terminal 502 n }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL