Throwing off the shackles of a legacy system

Abstract

Network information about cables, wire pairs, digital circuits, fiber, telephone numbers, central office equipment, and so on constitutes the basic building blocks for operating a local telephone company. GTE uses a mainframe system to maintain these information and service provisioning functions. The system, which we refer to as LegacyX, was developed and is owned by a third party vendor. Over the decades of LegacyX's operation, many other systems related to billing, service order entry, network testing, trouble administration, and inventory management have required interfaces to LegacyX. Without the information LegacyX provides, these systems would cease to function. Over the years, several patches have been applied to LegacyX to satisfy new requirements, and it has evolved into a massive black box. In summary, LegacyX has inherited all the disadvantages of large, embedded, legacy systems. It is very costly to maintain and virtually impossible to adapt to new services and technology. GTE had made 25 unsuccessful attempts to replace this legacy system. GTE was successful on the 26th attempt, replacing LegacyX with Domain (Distributed Object Management and Activation for Integrated Networks) in the Compania Dominicana de Telefonos (Codetel), the GTE owned telephone company in the Dominican Republic. This required a synergistic approach that brought together hardware, software, and people. This approach combined advanced software techniques with practical solutions to achieve a common goal shared by users, developers and managers.