SESSION CONTROL IN NETWORK FOR DIGITAL DATA PROCESSING SYSTEM WHICH SUPPORTS MULTIPLE TRANSFER PROTOCOLS

摘要

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. The node then compares the protocol names in the retrieved protocol towers with the protocol names over which it can communicate. If the protocol names in a retrieved tower match the protocol names in the node's tower, the node uses the communications parameters and address information in future communications with the object. If the node is unable to identify a retrieved protocol tower which matches its supported tower or towers, it is unable to communicate with the object.