The method 1, wherein the old and {HEAD ~ the new packet data} support node comprise SGSN and {TAIL ~ CGSN} 
support
The method 1 , wherein the old and { HEAD ~ the new packet data } support node comprise SGSN and { TAIL ~ CGSN }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL