23.3 The mobile terminated short message transfer procedure

29.0023GPPMobile Application Part (MAP) specificationRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The mobile terminated short message transfer procedure is used for forwarding a short message or several short messages from a Service Centre to a mobile subscriber. The message flow for the mobile terminated short message procedure for a single short message transfer is shown in figure 23.3/1.

Figure 23.3/1: Mobile terminated short message service procedures

1) Short Message (3GPP TS 23.040).

2) MAP_SEND_ROUTING_INFO_FOR_SM.

3) MAP_SEND_ROUTING_INFO_FOR_SM_ACK.

4) TCAP BEGIN (***)

4a) TCAP CONTINUE (***)

4b) MAP_MT_FORWARD_SHORT_MESSAGE.
The message should include the timer value used at the SMS-GMSC for the supervision of the MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

5) MAP_SEND_INFO_FOR_MT_SMS (*).

5a) MAP_CONTINUE_CAMEL_SMS_HANDLING (*)(**)

5b) MAP_SEND_INFO_FOR_MT_SMS (*)(**)

6) MAP_PAGE/MAP_SEARCH_FOR_MOBILE_SUBSCRIBER (*).

7) Page (3GPP TS 24.008 [35]).

8) Page response (3GPP TS 24.008 [35]).

9) MAP_PROCESS_ACCESS_REQUEST_ACK and
MAP_SEARCH_FOR_MOBILE_SUBSCRIBER_ACK (*).

10) MAP_SEND_INFO_FOR_MT_SMS_ACK (*).

11) Short Message (3GPP TS 24.011 [37]).

12) Short Message Acknowledgement (3GPP TS 24.011 [37]).

13) MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

14) Short Message Acknowledgement (3GPP TS 23.040).

(*) Messages 5), 5a), 5b), 6), 9), and 10) are not used by the SGSN.

(**) These messages are used only for a subscriber provisioned with MT-SMS-CSI in the VLR.

(***) If

a)
– the capacity of a message signal unit in the lower layers of the protocol is enough to carry the content of the MAP_OPEN request and the content of the MAP_MT_FORWARD_SHORT_MESSAGE request in a single TC message,

and

b) the SMS Gateway MSC operator and the serving node (MSC or SGSN) operator
agreed not to use the TCAP handshake countermeasure against SMS fraud for
messages exchanged between their networks (see 3GPP TS 33.204 [34a])

then
the TCAP handshake may be omitted.

The message flow for the mobile terminated short message procedure for multiple short message transfer is shown in figure 23.3/2.

Figure 23.3/2: Mobile terminated short message procedure for multiple short message transfer

1) Short Message (3GPP TS 23.040 [26]).

2) MAP_SEND_ROUTING_INFO_FOR_SM.

3) MAP_SEND_ROUTING_INFO_FOR_SM_ACK.

4) TCAP BEGIN (***)

4a TCAP CONTINUE (***)

4b) MAP_MT_FORWARD_SHORT_MESSAGE (note 1).
The message should include the timer value used at the SMS-GMSC for the supervision of the MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

5) MAP_SEND_INFO_FOR_MT_SMS (*).

5a) MAP_CONTINUE_CAMEL_SMS_HANDLING (*)(**)

5b) MAP_SEND_INFO_FOR_MT_SMS (*)(**)

6) MAP_PAGE/MAP_SEARCH_FOR_MOBILE_SUBSCRIBER (*).

7) Page (3GPP TS 48.008 [49]).

8) Page response (3GPP TS 24.008 [35]).

9) MAP_PROCESS_ACCESS_REQUEST_ACK and
MAP_SEARCH_FOR_MOBILE_SUBSCRIBER_ACK (*).

10) MAP_SEND_INFO_FOR_MT_SMS_ACK (*).

11) Short Message (3GPP TS 24.011 [37]).

12) Short Message Acknowledgement (3GPP TS 24.011 [37]).

13) MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

14) Short Message Acknowledgement (3GPP TS 23.040 [26]).

15) Short Message (3GPP TS 23.040 [26]).

16) MAP_MT_FORWARD_SHORT_MESSAGE (note 2).
The message should include the timer value used at the SMS-GMSC for the supervision of the MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

17) Short Message (3GPP TS 24.011 [37]).

18) Short Message Acknowledgement (3GPP TS 24.011 [37]).

19) MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

20) Short Message Acknowledgement (3GPP TS 23.040 [26]).

(*) Messages 5), 5a), 5b) 6), 9), and 10) are not used by the SGSN.

(**) These messages are used only for a subscriber provisioned with MT-SMS-CSI in the VLR.

(***) If

a) the capacity of a message signal unit in the lower layers of the protocol is enough to carry the content of the MAP_OPEN request and the content of the MAP_MT_FORWARD_SHORT_MESSAGE request in a single TC message,

and

then the TCAP handshake may be omitted.

NOTE 1: The "More Messages To Send" flag is TRUE.

NOTE 2: The "More Messages To Send" flag is FALSE.

In the multiple short message transfer the service MAP_MT_FORWARD_SHORT_MESSAGE can be used several times. However, the short message transfer is always acknowledged to the Service Centre before the next short message is sent.

In addition the following MAP services are used:

MAP_PROCESS_ACCESS_REQUEST (see clause 8.3); (*)

MAP_PAGE (see clause 8.2); (*)

MAP_SEARCH_FOR_MS (see clause 8.2); (*)

MAP_AUTHENTICATE (see clause 8.5); (*)

MAP_SET_CIPHERING_MODE (see clause 8.6); (*)

MAP_CHECK_IMEI (see clause 8.7);

MAP_FORWARD_NEW_TMSI (see clause 8.9); (*)

MAP_REPORT_SM_DELIVERY_STATUS (see clause 12.3);

MAP_INFORM_SERVICE_CENTRE (see clause 12.6);

MAP_TRACE_SUBSCRIBER_ACTIVITY (see clause 9.1); (*)

MAP_READY_FOR_SM (see clause 12.4).

(*) These services are not used by the SGSN.

A message flow example for the mobile terminated short message procedure for a single short message transfer in an environment that makes use of an SMS Router for MT-short-message-transfer is shown in figure 23.3/2a.

NOTE: This message flow can be applied only if no IP-SM-GW deployed in the same network.

Figure 23.3/2a Mobile terminated short message procedure with SMS Router

1) Short Message (3GPP TS 23.040 [26])

2) & 3) MAP_SEND_ROUTING_INFO_FOR_SM

NOTE: The HLR relays the message MAP_SEND_ROUTING_INFO_FOR_SM received from the SMS-GMSC to the SMS Router on SCCP level. How this is done is implementation specific.

4) MAP_SEND_ROUTING_INFO_FOR_SM

5) MAP_SEND_ROUTING_INFO_FOR_SM_ACK and conditionally MAP_INFORM_SERVICE_CENTRE

6) MAP_SEND_ROUTING_INFO_FOR_SM_ACK and conditionally MAP_INFORM_SERVICE_CENTRE

7) Conditionally: Inform Service Centre (3GPP TS 23.040 [26])

8) MAP_MT_FORWARD_SHORT_MESSAGE
The message should include the timer value used at the SMS-GMSC for the supervision of the MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

NOTE: In this example the SMS-GMSC decides to attempt delivery via MSC. Therefore the SCCP called party SSN shall be set to SSN for MSC.

9) MAP_MT_FORWARD_SHORT_MESSAGE
The message should include the timer value used at the SMS-GMSC for the supervision of the MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

10) MAP_MT_FORWARD_SHORT_MESSAGE_ERROR

NOTE: In this example delivery via the MSC is unsuccessful e.g. due to IMSI detached

11) MAP_MT_FORWARD_SHORT_MESSAGE_ERROR

12) MAP_MT_FORWARD_SHORT_MESSAGE

NOTE: In this example the SMS-GMSC decides to retry delivery via the SGSN. Therefore the SCCP called party SSN shall be set to the SSN for SGSN.

13) MAP_MT_FORWARD_SHORT_MESSAGE
The message should include the timer value used at the SMS-GMSC for the supervision of the MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

14) MAP_MT_FORWARD_SHORT_MESSAGE_ACK

NOTE: In this example delivery via SGSN is successful

15) MAP_MT_FORWARD_SHORT_MESSAGE_ACK

16) Conditionally: MAP_REPORT_SM_DELIVERY_STATUS

NOTE: In this example unsuccessful delivery via MSC and successful delivery via SGSN is reported

17) MAP_REPORT_SM_DELIVERY_STATUS_Ack

18) Short Message Acknowledgement (3GPP TS 23.040 [26]).

A message flow example for the mobile terminated short message procedure for a single short message transfer in an environment that makes use of an IP-SM-GW (see 3GPP TS 23.204 [134]) for MT-short-message-transfer is shown in figure 23.3/2b.

NOTE: SMS Routers can apply this message flow as well.

Figure 23.3/2b Mobile terminated short message procedure with IP-SM-GW

1) Short Message (3GPP TS 23.040 [26])

2) MAP_SEND_ROUTING_INFO_FOR_SM

the message is forwarded to the IP-SM-GW assigned to the recipient of the SM

the message may contain IP-SM-GW Guidance support indication

3) MAP_SEND_ROUTING_INFO_FOR_SM

4) MAP_SEND_ROUTING_INFO_FOR_SM

since the message is received from an IP-SM-GW, it is not forwarded to an IP-SM-GW

5) MAP_SEND_ROUTING_INFO_FOR_SM_ACK and conditionally MAP_INFORM_SERVICE_CENTRE

6) MAP_SEND_ROUTING_INFO_FOR_SM_ACK and conditionally MAP_INFORM_SERVICE_CENTRE

The IP-SM-GW returns its own address within the network node number parameter

The message may include IP-SM-GW Guidance

7) Conditionally: Inform Service Centre (3GPP TS 23.040 [26])

8) MAP_MT_FORWARD_SHORT_MESSAGE

If the IP-SM-GW-Guidance support indicator was present in message 2 and IP-SM-GW-Guidance was present in message 6, message 8 shall contain the used timer value for supervision of MAP_MT_FORWARD_SHORT_MESSAGE_ACK; the used timer should be identical to the recommended value received in message 6 to ensure that the IP-SM-GW can attempt delivery to multiple domains if necessary and shall not be lower than the minimum value received in message 6 to ensure that an IP-SM-GW can attempt delivery to at least one domain.
Otherwise, The message should include the timer value used at the SMS-GMSC for the supervision of the MAP_MT_FORWARD_SHORT_MESSAGE_ACK.

9) MAP_MT_FORWARD_SHORT_MESSAGE_ACK

10) Conditionally: MAP_REPORT_SM_DELIVERY_STATUS

NOTE: As an IP-SM-GW is deployed the message is acknowledged ignoring its content

11) MAP_REPORT_SM_DELIVERY_STATUS_Ack

12) Conditionally: MAP_REPORT_SM_DELIVERY_STATUS

since the message is received from an IP-SM-GW, it is processed

13) MAP_REPORT_SM_DELIVERY_STATUS_Ack

NOTE: Step 12 and 13 is independent of steps 10, 11, and 14. They can run in parallel.

14) Short Message Acknowledgement (3GPP TS 23.040 [26]).