Abstract: This invention provides for a system and method for upgrading an ATM network to a new release of a vendor's ATM platform, or for converting an ATM network to a different vendor's ATM platform, preferably without experiencing any service disruptions. The system and method upgrade involves first reorganizing an existing redundant-based ATM network by splitting the links, for example, fiber links, within the existing redundant-based ATM network among two parallel networks, Network A and Network B. Network A can be changed at this stage. Then the circuits from Network B are moved to Network A by using Bridge and Roll techniques. This hitless procedure allows for the migration of the customer traffic from Network B to Network A without customer traffic disruptions.

Abstract: In an environment of competitive local and interexchange carriers, offering number portability between local carriers serving a common region and between switches serving that region, each local carrier accesses a regional database to determine the identity of the carrier and switch serving a local customer. In addition, interexchange carriers access a national database to determine the identity of the carrier and switch serving the customer specified by the number dialed by an originating customer. For customers requiring high reliability service, alternate carriers can be used to serve such customers in case the primary carrier is unavailable; the databases identify these alternate carriers. Advantageously, this arrangement allows a high degree of freedom of movement of customers between carriers and geographic relocation without requiring a number change.

Abstract: In an environment of competitive local and interexchange carriers, offering number portability between local carriers-serving a common region and between switches serving that region, each local carrier accesses a regional database to determine the identify of the carrier and switch serving a local customer. In addition, interexchange carriers access a national database to determine the identity of the carrier and switch serving the customer specified by the number dialed by an originating customer. For customers requiring high reliability service, alternate carriers can be used to serve such customers in case the primary carrier is unavailable; the databases identify these alternate carriers. Advantageously, this arrangement allows a high degree of freedom of movement of customers between carriers and geographic relocation without requiring a number change.