23.3.6 Procedure in the SMS Router
29.0023GPPMobile Application Part (MAP) specificationRelease 17TS
If SMS Router is deployed together with IP-SM-GW, then mobile terminated short message transfer process for IP-SM-GW applies as described in clause 23.3.7.
The mobile terminated short message transfer process in the SMS Router is shown in figure 23.3/14.
Procedure MT_SM_SMS_ROUTER sheet 2: Allocated MT Correlation IDs have a limited lifetime, managed by Timer T1. The value of Timer T1 shall be operator configurable (its value being dependant on such factors as subscriber base, network size, number of roaming/SMS‑interworking partners, average and peak SMS traffic load, etc.).
The value of the timer T1 shall cover at least the time indicated by the SM Delivery Start Time and SM Delivery Timer and, if the SMS Router support the Alert Service Centre procedure specified in clause 12.5, the Maximum Retransmission Time signalled in the MAP-MT-FORWARD-SHORT-MESSAGE.
Procedure MT_SM_SMS_ROUTER sheet 2: MAP parameters to be stored against the MT Correlation ID are IMSI, networkNode-Number, gprsNodeIndicator, and additional-Number (if and as received within MAP_SEND_ROUTING_INFO_FOR_SHORT_MESSAGE_cnf), and optionally MSISDN as received within MAP_SEND_ROUTING_INFO_FOR_SHORT_MESSAGE_ind from the SMS-GMSC (and relayed by the HLR)). The SMS Router may also store the GT, or just the CC and NDC parts of the GT, of the SMS-GMSC from which the MAP_SEND_ROUTING_INFO_FOR_SHORT_MESSAGE_ind was received.
Procedure MT_SM_SMS_ROUTER sheet 3: The SCCP called party SSN received with Open_ind is used to decide whether the new dialogue is opend with the MSC or with the SGSN.
The detail of replacing RP-OA is described in TS23.040 [26].
Procedure MT_SM_SMS_ROUTER sheet 4: The decision box "Retry expected" takes the "Yes" exit if two addresses were received from the HLR, the first delivery attempt was unsuccessful, and the second attempt has not yet been made.
Procedure MT_SM_SMS_ROUTER sheet 4: The task "Release MT Correlation ID" includes deleting of data stored against the MT Correlation ID.
If the MT Forward Short Message Request includes the Maximum-Retransmission-Time IE, the SMS Router shall store the SMS-GMSC address and, if available, the SMS-GMSC Diameter Identity received in the request and replace it by its SMS Router address (E.164 number) and, if available, its SMS Router Diameter Identity when forwarding the request to the MME (via an IFW), SGSN or MSC.
If the MT Forward Short Message Response includes the Requested-Retransmission-Time IE, the SMS Router shall include the User Identifier Alert IE when forwarding the response to the SMS-GMSC.
NOTE: The User Identifier Alert is further used in the Alert Service Centre procedure specified in clause 12.5 to enable the SMS-GMSC to identify and retransmit all pending MT SMS messages towards the destination user.
When receiving an Alert Service Centre request from an MME (via an IWF), SGSN or MSC, the SMS-Router shall replace the IMSI received in the IMSI IE by the User Identifier Alert previously sent in the MT Forward Short Message Response, and forward that request to the SMS-GMSC.