03.553GPPDual Transfer Mode (DTM)Release 1999Stage 2TS
In this procedure, the mobile station sends a GPRS Attach Request message to the SGSN. The sequence of messages is very similar to the Routeing Area Update procedure, shown in figure 14 and figure 15. The presence of the Gs interface (i.e. network mode of operation I or II/III) needs to be indicated in the SACCH (e.g. SI 6) so that the MS knows what attach type needs to be performed.