FIG 5 illustrates an embodiment with a dual mode SGSN, here denoted old SGSN, which supports {HEAD ~ access} over WCDMA as well as {TAIL ~ 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 
over
FIG 5 illustrates an embodiment with a dual mode SGSN , here denoted old SGSN , which supports { HEAD ~ access } over WCDMA as well as { TAIL ~ 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
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