There is interest in providing 3GPP messaging services across WLAN, and, more generically across any form of 3GPP IP access. Although some initial work has been documented within Annex D of the WLAN interworking stage 2 (TS 23.234), there are many topics that cannot be tackled in isolation. These include (but are not limited) to:

1. the impact on existing SMS services and the HSS (e.g. the impact on SMS message waiting flags and on voice mail services.) If this is not studied, then there is a risk that existing operator services will be degraded by the introduction of "SMS over WLAN";
2. the investigation of the use of SS7 and/or IP protocols to communicate with the SMS-GMSC/SMS-IWMSC and the HSS;
3. providing SMS/MMS services over any 3GPP IP access needs authentication (e.g. specification of security mechanisms);
4. potential synergies between solutions for SMS, MMS and IMS messaging (e.g. common (re)registration mechanisms);
5. addressing mechanisms when multiple IP-SMS Gateways are in use; and
6. reliable deregistration mechanisms to cope with cases when the 3GPP IP access link is lost suddenly (e.g. when WLAN coverage is lost).
7. mechanisms to handle SMS and MMS when there is more than one 3GPP IP connection active with the mobile (e.g. a WLAN/GPRS/UMTS card may be GPRS attached and/or CS attached while also having the WLAN connection active).

The overall objective is to enhance the 3GPP specifications to support delivery of SMS and MMS over WLAN and any other 3GPP IP access in a manner which guarantees existing SMS and MMS services are not degraded.

The present document investigates solutions for providing 3GPP messaging services across WLAN, and, more generically across any form of IP access that is part of the 3GPP system.

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.