Section: 5.3 Identification of the HSS for SMS
Content: The HSS may also be identified by a HSS-ID. The HSS-ID shall consist of decimal digits (0 through 9) only and be composed of the MCC consisting of three digits, the MNC consisting of two or three digits and an index consisting of one to several digits. The number of digits in the HSS-ID shall not exceed 15. This composition is compatible with the IMSI one. The HSS-ID shall not be identical to the complete IMSI of a UE. NOTE: The composition of the HSS-ID is compatible with the composition of the IMSI in clause 2.2 for routing purposes.