Numbering and addressing aspects of the UMTS's integration into the fixed network infrastructure

We consider the addressing and numbering aspects of the Universal Mobile Telecommunications System's (UMTS) integration in the fixed network infrastructure. The numbers, addresses, and identifiers required to support personal and terminal mobility in UMTS are presented. Then an addressing mechanism to be employed in UMTS is proposed. The study clearly discriminated between the addressing mechanisms used in the access and core networks. This was done because in the UMTS access network (UAN) we have the freedom to define UMTS-specific addresses, while in the core network we are restricted to using mobile routing numbers (MRNs). The roles of the various numbers, addresses, and identifiers required for UMTS and their dynamic interdependencies are analyzed. These dependencies form the addressing requirements for UMTS. In the UAN, the addressing mechanism is based on the mature and flexible OSI addressing framework. Furthermore, based on a connectionless mode for signaling transport, a flexible routing mechanism as well as an efficient mechanism for keeping track of the mobile terminal can be offered. In the core network addressing is based on the traditional CCITT numbering scheme. The relationship between international mobile user numbers (IMUNs) used as dialing information, international mobile user identity (IMUI) used to identify users, and MRNs (used in UMTS call handling) is clarified. It is demonstrated that MRNs can provide a viable solution that is backward-compatible with pre-B-ISDN infrastructure. The interactions with the UMTS distributed database necessary so a UMTS call can proceed over traditional PSTNs or N-ISDNs are identified.