The method 1, wherein establishing a session between {HEAD ~ the first control unit} and {TAIL ~ the proxy server} includes coupling through a second firewall, the proxy server being inside the second firewall 
The method 1 , wherein establishing a session between { HEAD ~ the first control unit } and { TAIL ~ the proxy server } includes coupling through a second firewall , the proxy server being inside the second firewall
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH