16.1.1 Architecture

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

When the WLAN is considered as trusted by the operator, the Trusted WLAN Access Network (TWAN) is interfaced with the EPC as a trusted non-3GPP access via the STa interface to the 3GPP AAA Server/Proxy and the S2a interface to the PDN GW.

Roaming scenarios where the TWAN does not support a STa interface to the UE’s registered PLMN or to the UE’s HPLMN are not supported in this release of the specification.

Figure 16.1.1-1: Non-roaming architecture for Trusted WLAN access to EPC

Figure 16.1.1-2: Roaming architecture for Trusted WLAN access to EPC – Home Routed, VPLMN provides WLAN service

Figure 16.1.1-3: Roaming architecture for Trusted WLAN access to EPC – Local break-out

Figure 16.1.1-4: Roaming architecture for Trusted WLAN access to EPC – Home routed, HPLMN provides WLAN service