ETSI TS 123 234 specifies the network selection, including authentication and access authorization using authentication, authorization and accounting (AAA) procedures used for the interworking of the 3GPP system and WLANs. In addition to these, the present document also specifies the tunnel management procedures used for establishing an end-to-end tunnel from the WLAN UE to the 3GPP network via the Wu reference point.

The present document is applicable to the WLAN user equipment (UE) and the network. In this technical specification the network includes the WLAN and 3GPP network.

Tunnel management signalling is carried between WLAN-UE and WLAN by WLAN access technology specific protocols, however this signalling is transparent to the WLAN.

Tunnel management procedures are defined to be independent of the underlying WLAN access technology and as such can be reused independently of the underlying technology.

The present document specifies procedures within I-WLAN necessary in order for IMS emergency calls to be supported when I-WLAN is used as the underlying access network. These involve both network selection as well as tunnel management procedures.

WLAN Network Selection supersedes I-WLAN for UE WLAN selection as specified in 3GPP TS 24.302 [28] from Rel-12 onwards.

No further changes to this specification are intended. If any future evolution of the procedures in this specification is necessary, it should be documented in other specifications.