FIG 5 illustrates an embodiment with a dual mode SGSN, here denoted old SGSN, which supports {HEAD ~ access} over {TAIL ~ WCDMA} as well as GSM/GPRS, i.e. it shows an IRAT PS handover or an intra SGSN WCDMA to GSM/GPRS handover with only of those parts of the execution phase which are necessary for carrying out the inventive concept 
FIG 5 illustrates an embodiment with a dual mode SGSN , here denoted old SGSN , which supports { HEAD ~ access } over { TAIL ~ WCDMA } as well as GSM / GPRS , i.e. it shows an IRAT PS handover or an intra SGSN WCDMA to GSM / GPRS handover with only of those parts of the execution phase which are necessary for carrying out the inventive concept
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH