This Annex specifies interworking between the EPS and 3GPP 2G and/or 3G SGSNs, which provide only Gn and Gp interfaces but no S3, S4 or S5/S8 interfaces, i.e. these Gn/Gp SGSNs provide no functionality that is introduced specifically for the EPS or for interoperation with the E-UTRAN.
Interoperation scenarios for operating E-UTRAN with a PLMN maintaining Gn/Gp SGSNs are supported only with a GTP-based S5/S8.
The S5/S8 interface for the Operator with Gn/Gp SGSNs will be GTP-based, but can be changed to PMIP-based S5/S8 when the Gn/Gp SGSNs evolve to S4 SGSNs.
For these interoperation scenarios the GERAN/UTRAN has to support interoperation with E-UTRAN.
TS 23.682 defines the Monitoring Events feature, and TS 23.060 specifies that the Monitoring Events feature for the Gn/Gp SGSN is not supported. Therefore, during interoperation with Gn/Gp SGSNs Monitoring Event information shall not be expected by the MME/S4-SGSN from a Gn/Gp SGSN, nor shall the MME/S4-SGSN or the HSS transfer Monitoring Event information to a Gn/Gp SGSN. This applies to all operations defined in this Annex.
In the roaming scenario the vPLMN operates Gn/Gp 2G and/or 3G SGSNs as well as MME and S-GW for E-UTRAN access. The hPLMN operates a P-GW.
Roaming and inter access mobility between Gn/Gp 2G and/or 3G SGSNs and an MME/S-GW are enabled by:
Gn functionality as specified between two Gn/Gp SGSNs, which is provided by the MME, and
Gp functionality as specified between Gn/Gp SGSN and Gn/Gp GGSN that is provided by the P-GW.
All this Gp and Gn functionality bases on GTP version 1 only.
The architecture for interoperation with Gn/Gp SGSNs in the non-roaming case is illustrated in Figure D.2.1-1.
In the non-roaming scenario the PLMN operates Gn/Gp 2G and/or 3G SGSNs as well as MME and S-GW for E-UTRAN access.
Intra PLMN roaming and inter access mobility between Gn/Gp 2G and/or 3G SGSNs and an MME/S-GW are enabled by:
Gn functionality as specified between two Gn/Gp SGSNs, which is provided by the MME, and
Gn functionality as specified between Gn/Gp SGSN and Gn/Gp GGSN that is provided by the P-GW.
All this Gn functionality is based on GTP version 1 only.
The architecture for interoperation with Gn/Gp SGSNs in the non-roaming case is illustrated in Figure D.2.2-1.