Browse Prior Art Database

Network/440 Protocol Concept (RFC0187) Disclosure Number: IPCOM000004126D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2019-Feb-10
Document File: 11 page(s) / 16K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D.B. McKay: AUTHOR [+1]

Related Documents

10.17487/RFC0187: DOI

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 13% of the total text.


Network Working Group Douglas B. McKay Request for Comments #187 Donald P. Karp NIC #7131 IBM Thomas J. Watson Research Center Categories: C3,C4,C5,C6,D7 Yorktown Heights, New York Update: None Obsoletes: None

This RFC is being circulated as an information RFC. Its intent is to convey some of the thinking and philosophy that went into IBM’s network protocol and overall network design.

[Page 1]


Network/44O is an experimental project in computer netting that was undertaken by the Computer Science Department of IBM Research. The primary objectives of the project have been to understand netting, identify design problems and implement the solutions to these problems.

The above objectives have been met since a network has been built and is presently being operated by the project. Implementation discussions transpired with another department at Research in order to define a realistic user system interface. The protocol defined for the project’s network is also the basis for the operation of an IBM OS network.

The Network/44O project has also been involved in the philosophical and architectural concepts of network systems. The basic premise in our work is the concept of a logical network machine.(1) The main theme is to treat all systems involved in the network as a part of a single (large) multiprocessor system. Although many of the ideas have been based on hypothetical concepts, an equal number of ideas were derived from our network implementation and operating experience.

The scope of this paper is to describe the philosophy and definition of a network protocol that is not restricted to any physical configuration. This is exemploified by the fact that a major portion of the ideas are implemented in IBM’s two major operational networks, one of which is a distributed configuration and the other a star configuration.

(1) Intenet - Report 2, February 1, 1970, Computer Science Department, IBM Corporation, T. J. Watson Research Center, Yorktown Heights, New York.


There was a necessity to delineate many network functions in setting up an operating protocol. These functions included switching control, buffer control, message control, and operating control. The operating control function becomes further complicated as the user is able to program the network as if it were a single operating system. The protocol had to be further broken dowm into detailed functions in order to cope with error recovery and handling techniques.

The original thoughts on handling these functions were to provide two basic realms of control. The net control is a higher level function that recognizes and controls all aspects of net jobs and the execution of job steps in the network machine. In addition, a communication control facility (referred to as an "Express Interpreter") was incorporated to provide fast service for all messages that were to be moved between user systems without intervention by the net controller.