Proxy server 105 may aggregate and store {TAIL ~ performance data} provided by {HEAD ~ control units} 150 and 165, respectively 
Proxy server 105 may aggregate and store { TAIL ~ performance data } provided by { HEAD ~ control units } 150 and 165 , respectively
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH