Abstract: A distributed digital data processing system includes a plurality of nodes which communicate over a network. A node maintains one or more objects, each of which may be a file, that is, an addressable unit in the system, such as a program, database, text file, or the like, or a directory which may contain one or more files or other directories. One node maintains a naming service which associates each object in the system with one or more protocol towers. Each protocol tower identifies the object name and a series of entries each identifying a name for each of the protocol layers, along with the communications parameters and address information, to be used in communicating with the object. When a node requires access to an object maintained by another node, it first retrieves from the naming service the protocol towers for the object. The node also maintains a tower identifying the names of each of the protocols over which it can communicate.