NYNEX Science and Technology and Fujitsu Network Switching Systems of North America undertook development of an interface between a NYNEX Network Management System (NetWindow) and Fujitsu's Fetex-150 Broadband Switching System (B-ISDN) for a specific service using a (Bellcore) standard information model based on the OSI Common Management Information Protocol (CMIP). CMIP is a powerful but complex protocol. The modeling flexibility and enhanced vocabulary of the protocol increase the level of effort required to implement both manager and agent code. The areas of CMIP that cause the hardest implementation problems revolve around unbounded recursions in either the model or protocol. Careful selection of limitations on the information model structure, and CMIP features allows sufficient power at controllable implementation expense. By devising and applying a series of simplifying principles during the development of a comprehensive set of implementation agreements, the authors were able to contain the implementation complexity while retaining the power of the protocol. Examples of the simplifying steps are given to illustrate these principles.>