ETSI TS 123 040 describes the Short Message Service (SMS) for GSM/UMTS networks. It defines:

• the services and service elements;
• the network architecture;
• the Service Centre functionality;
• the SMS Router functionality;
• the MSC functionality (with regard to the SMS);
• the SGSN functionality (with regard to the SMS);
• the MME functionality (with regard to the SMS);
• the routing requirements;
• the protocols and protocol layering;

for the Mobile Originated and Mobile Terminated Short Message Service Teleservices, as specified in 3GPP TS 22.003 [2] and 3GPP TS 22.105 [32].

The use of radio resources for the transfer of short messages between the MS and the MSC or the SGSN or the MME is described in 3GPP TS 24.011 [13].

The present document also describes the Short Message Service (SMS) for EPS networks supported via "SMS in MME" (see 3GPP TS.23.272 [45], annex C).

The present document also describes the SGSN supporting Diameter based protocol for SMS between the SGSN and the central SMS functions (SMS-GMSC, SMS-IWMSC, SMS-Router) in annex J.

The network aspects of Short Message Service provision are outside the scope of the present document (i.e. the provision of network connectivity between the PLMN subsystems). There is no technical restriction within the present document for the transfer of short messages between different PLMNs. Any such restriction is likely to be subject to commercial arrangements and PLMN operators must make their own provision for interworking or for preventing interworking with other PLMNs as they see fit.

The required and assumed network service offered to the higher layers is defined in the present document.