Since the introduction of a number of distributed computing environments, there has been an increase in the number of network and application services that are distributed throughout large networks. The distribution of services makes it difficult for users and mobile agents to locate the required host services. This problem is more pronounced for mobile agents which unlike human users are not able to draw on a variety of information sources and services. Mobile agents make use of directory services to obtain location information. This paper presents a unification model for extending directory services. The proposed model provides a standard directory service in a multiple protocol environment for the interface, location and navigation of distributed services