6. Signaling and Control
7. PORTABILITY
Local Number Portability (LNP) is a pressing issue, and a concern for any projected addressing system. As presently envisioned portability will permit subscribers to retain their telephone address, and the address of any of their other telecommunication devices, regardless of which LEC they subscribe to or where they might relocate within their original NPA (Toth, 1995). The Telecommunication Act of 1996 has mandated that portability must be implimented within the United States, beginning 31 March 1998. Regardless of the best efforts of the North American Numbering Council (NANC) of the Federal Communications Commission (FCC), the schedule is falling further and further behind, with serious nationwide implimentation delayed by perhaps a year.
 
The objective of the Telecommunication Act is to promote market competition between the LECs. Consequently all of the various additional addresses subscribers might have for fax machines, cellular phones and so forth would be equally portable within any NPA. Unlike the LTNP options, according to MTAS these latter addresses are simply sub-addresses of the subscriber's primary address. That portability extending to any primary address will extend equally to all of its sub-addresses is a natural outcome of MTAS. In this manner any user can subscribe to different LECs for different services, increasing market competition. The PSTN will have to be extensively reprogrammed to achieve this full NPA portability, a task now obvious to be far more complex than would be reprogramming for MTAS.
 
A central database operated by a Portability Administrator will have to be established in each NPA to cover all of the LECs operating in that area. Subscribers moving outside their COX area who request the same addresses at their new locations will have those addresses registered with the Portability Administrator. Calls to the old COXs will be shunted to the central database and from there to the new locations. With MTAS all of the sub-addresses would be automatically registered with the database operator.

Contents

8. IMPLEMENTATION