A.1 Definitions

23.0603GPPGeneral Packet Radio Service (GPRS)Release 17Service descriptionStage 2TS

The SGSN knows from the subscription data the following parameters (S for Subscribed): PDP type (S), PDP address (S), APN (S), and VPLMN address allowed. In addition, the S4-SGSN and MME receive a PDN subscription context that is marked as default (and associated default APN) for E-UTRAN UEs.

The SGSN may know from configuration the Local APN supporting a given PDP type. This APN is called APN (SGSN) and does not include an APN Operator Identifier. APN (SGSN) shall not be an APN with LIPA permisssions set to "LIPA-only" or "LIPA-conditional".

The SGSN knows the parameters requested by the MS (R for Requested): PDP type (R), PDP address (R), and APN (R). APN (R) is the APN Network Identifier requested by the MS.

In case of "an APN chosen by the SGSN" the activated PDP context is always linked with a dynamic PDP address.

An MS may have multiple subscription records for the same PDP type and the same PDP address, but with different APNs.

An MS may have one or two subscription records with the same PDP type and the same APN: one with a static PDP address, one with a dynamic PDP address.

An MS may have multiple subscription records with the same APN, but with different PDP types.

When the MS is in its HPLMN, if the MS requests an APN that does not correspond to any GGSN or P-GW of its HPLMN, the request shall be rejected by the SGSN. When the MS is in a VPLMN, if the MS requests an APN that does not correspond to any GGSN or P-GW of its HPLMN nor of this VPLMN or any of its associated PLMNs when the VPLMN is a shared network, the request shall be rejected by the SGSN.

If APN (S) = wild card (see TS 23.003 [4]), it means either:

– that a Local APN (a locally defined PDN) has to be chosen by the SGSN (APN (SGSN)) if no APN (R) has been provided; or

– that a PDP context with dynamic PDP address may be activated towards any APN requested by the MS.

The PDN subscription context that is marked as default for the default bearer activation, defines a Default APN that takes precedence over the locally defined APN for the S4-SGSN and MME.

In order to derive APN (R) from the APN sent by the MS, the SGSN shall check if the APN sent by the user ends with ".gprs". If not, then APN (R) is equal to APN sent by the MS. If yes, then APN (R) is the APN sent by the MS without the three last labels.

NOTE 1: If yes, then the APN-OI shall be saved for later use, see Figure A.4.

NOTE 2: If the APN OI Replacement field in the subscriber’s profile is present, then the default APN-OI is overwritten before performing a DNS look-up on the full APN.

NOTE 3: The APN as constructed by the SGSN for GGSN resolution takes into account the APN-OI Replacement field. This differs from the APN that is provided in charging data and to another SGSN and MME over the Gn, S3 and S16 interfaces as well as to the Serving GW and PDN GW over the S4 and S5/S8 interface, in that the APN-OI Replacement field is not applied. See clause 13.2 of the present document for more details.

NOTE 4: The UE should not be provisioned with the APN-OI Replacement FQDN, otherwise APN resolution might fail.

For deriving a GGSN by the procedure defined in the SDL Diagram, PDPtype(R) shall be assumed equal to PDPtype(S) if PDPtype(R) is IPv4 or IPv6 and PDPtype(S) is IPv4v6.