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