Address translation in telecommunication features

Address translation causes a wide variety of interactions among telecommunication features. This article begins with a formal model of address translation and its effects, and with principles for understanding how features should interact in the presence of address translation. There is a simple and intuitive set of constraints on feature behavior so that features will interact according to the principles. This scheme (called "ideal address translation") has provable properties, is modular (explicit cooperation among features is not required), and supports extensibility (adding new features does not require changing old features). The article also covers reasoning in the presence of exceptions to the constraints, limitations of the theory, relation to real networks and protocols, and relation to other research.