IMS Network Element - IP-SM-GW (for Short Message)

IMS Network Element - IP-SM-GW (for Short Message) (Study Note)

General functions of IP-SM-GW:
- Determine the domain (CS/PS or IMS)
- Connect to the SMS‑GMSC or SMS-IWMSC or HSS via interfaces
- Acquire and maintain knowledge of the association between the MSISDN, IMSI and the address of the S‑CSCF serving of the user;
- Act as an AS towards the IMS core;
- For terminating procedures, to map the recipient’s address from an MSISDN/IMSI to TEL URI format
- Perform domain selection to choose the appropriate domain to deliver a message from the HSS
- Check that it has a valid address in SMS for the sender as well as the recipient when receiving an IMS message for an SMS user
- etc.

Two Mechanisms:
- Transport-level interworking is done by carrying encapsulated Short Messages into IMS messages
- Service-level interworking is done between Short Messages and Instant Messages in IMS

Further Information: https://docs.google.com/fileview?id=F.b6e7cac8-17fa-4aa2-a11e-c7fef781b452