7. Portability

Because MTAS is compatible with the present addressing system, it can be implemented in stages: NPA by NPA. Upon implementation in any NPA the MTAS is completely invisible. It becomes functional only for those users who choose to subscribe to MTAS, and MTAS would be functional only within that NPA. Because MTAS does not consume telephone addresses, these users can have both their MTAS and non-MTAS addresses functioning simultaneously during a transition period. As MTAS is implemented in adjacent NPAs, the functionality of MTAS will extend between contiguous NPAs using either LEC to LEC or LEC to IXC connectivity.
Compared to PSTN reprogramming and interconnection requirements for mandatory NPA portability, implementing MTAS will be straight forward as far as SS7 routing and identification requirements are concerned, and new interconnections will not be required. For the greatest efficiency in implementation both portability and MTAS reprogramming should be combined.