The problems of defining features, services, and feature interactions in telecommunication systems are discussed. Several ways of classifying feature interactions are surveyed. Existing approaches for solving the feature-interaction problem are reviewed. It is seen that no full approach exists; they are all partial solutions. The approaches are divided into three classes: avoidance, detection, and resolution. Avoidance looks at ways to prevent undesired feature interactions. Detection assumes that feature interactions will be present, and determines methods for identifying and locating them. Resolution assumes that feature interactions will be present and detected, and looks at mechanisms for minimizing their potential adverse effects. >