4.1 General

23.1213GPPArchitectural requirements for Release 1999Release 1999TS

The phase 1 UMTS/Release ’99 GSM standards should provide the capability to support:

– a core network based on an evolved 2G MSC and an evolved SGSN;

– an optionally evolved Gs interface;

– mobile Ipv4 with Foreign Agent care-of addresses to end users over the UMTS/GPRS network, where the FA is located in the GGSN;

– class A GSM’ mobiles;

– transcoder location shall be according to 23.930;

– UMTS/IMT2000 Phase1 (Release 99) network architecture and standards shall allow the operator to choose between Integrated and Separated core networks for transmission (including L2);

– the UMTS standard shall allow for both separated and combined MSC/VLR and SGSN configurations;

– the UE shall be able to handle separated or combined MSCs and SGSNs;

– there can be several user planes to these CN nodes.

The following general concepts should be followed:

– separate the layer 3 control signalling from the layer 2 transport discussion (do not optimise layer 3 for one layer 2 technology);

– MSC-MSC layer 3 call control is out of scope of standardisation in SMG;

– as future evolution may lead to the migration of some services from the CS-domain to the PS-domain without changes to the associated higher-layer protocols or functions. UMTS release 99 shall provide the flexibility to do this in a way that is backwards compatible with release 99 Ues provided this does not introduce significant new complexity or requirements in the system.