C.3 Reference Points

23.2723GPPCircuit Switched (CS) fallback in Evolved Packet System (EPS)Release 17Stage 2TS

C.3.1 General

The following reference points specifically enable support of SMS in MME.

C.3.2 S6a

In order to support "SMS in MME" the S6a shall allow the MME to request SMS subscription information and to register as a serving node for SMS. If the HSS supports this and has SMS subscription information available, it sends SMS subscription data to the MME. The SMS subscription data include for example the barring status of MO-SMS and MT-SMS and the MSISDN. If the HSS determines that the MME shall be deregistered for SMS, it shall indicate to the MME that it is not registered for SMS.

C.3.3 S6c

In order to support "SMS in MME" the Diameter based S6c shall allow the SMS central functions to request routing information from the HSS.

C.3.4 SGd

In order to support "SMS in MME" the Diameter based SGd shall provide the Short Message Relay Layer (SM-RL) between MME serving the UE and SMS central functions.