Much of previous Distributed Artificial Intelligence research has sought either to bring identical agents into closely coordinated groups, or to loosely coordinate the actions of dissimilar agents. The research described here explores close cooperation among heterogeneous agents, and is motivated by the requirements of a specific application in telecommunications network management: customer network control and joint private/public network management. In this domain, agents that manage the private and public networks must cooperate closely to provide satisfactory solutions to common network problems, yet they possess inherently distinct problem solving knowledge: private (or customer) networks are defined as logical networks constructed with the physical facilities provided by the public network. Thus, some of the network entities that define one agent's world knowledge are known by other agents at a different level of abstraction, creating a complex interdependence among agent problem solving activities. This paper provides some basic motivation for cooperative distributed problem solving and its application to communication network management in general, and reports on efforts to understand the nature of cooperation and the functionality of agents in the customer network control domain. In the process, the paper describes a three-agent facility failure problem and an associated interagent cooperation scenario, and presents a research testbed, TEAM-CPS, that explores cooperative problem solving and multiagent interaction. © 1990.