COTS Products in Air Traffic Control

National Air Traffic Services' (NATS) requirements for system integrity are discussed and a number of examples of the use of COTS products to meet these rigorous requirements are presented. A brief history of network evolution is followed by examples of how standard products have been used to achieve high integrity solutions. NATS have used time distribution systems for many years, starting with bespoke designs. We are now implementing COTS-based designs and meeting tough requirements at reasonable lifecycle cost. System management facilities are based on COTS but use databases and applications; therefore modifications are unavoidable. The objective is to use the native features of the COTS products and avoid unnecessary modification, which leads to increased costs.