The quantity and {HEAD ~ nature} of actual message transmissions involved in {TAIL ~ the primary communications test} varies in accordance with embodiments of the invention 
The quantity and { HEAD ~ nature } of actual message transmissions involved in { TAIL ~ the primary communications test } varies in accordance with embodiments of the invention
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH