One reason for this is {HEAD ~ the limited capability} of {TAIL ~ these systems} to actually ensure proper performance of the client clocks 
of
One reason for this is { HEAD ~ the limited capability } of { TAIL ~ these systems } to actually ensure proper performance of the client clocks
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH