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Host-IMP interface (RFC0007)

IP.com Disclosure Number: IPCOM000007190D
Original Publication Date: 1969-May-01
Included in the Prior Art Database: 2002-Mar-05
Document File: 8 page(s) / 13K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

G. Deloche: AUTHOR

Abstract

II. Scope of the software organization. II-1 Network program II-2 Handler program

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 35% of the total text.

Network Working Group                                         G. Deloche

Request for Comment: 7           University of California at Los Angeles

NIC: 4693                                                       May 1969

                           Host-Imp Interface

      G. Deloche      -->  Prof. J. Estrin

                           Prof. L. Kleinrock

                           Prof. B Bussel

                           D. Mandell

                           S. Crocker

                           L. Bonamy

   Object: Arpa Network - Specification Outlines for Host-IMP (HI)

   Interface Programs.

                                  Outline

   I.  Introduction

   II.  Scope of the software organization.

           II-1    Network program

           II-2    Handler program

   III.  Questions

   [The original of RFC 7 was hand-written, and only partially illegible

   copies exist.  RFC 7 was later typed int NLS by the Augmentation

   Research Center (ARC) at SRI.  The following is the best

   reconstruction we could do.  RFC Editor.]

Deloche                                                         [Page 1]

RFC 7                      Host-IMP Interface                   May 1969

I.  Introduction

   This paper is concerned with the preliminary software design of the

   Host IMP interface.  Its main purpose is on the one hand to define

   functions that will be implemented, and on the other hand to provide

   a base for discussions and ...(unreadable).

   This study is based upon a study of the BBN Report No. 763.

II.  Scope of the software organization.

   The system is based upon two main programs: the Handler program that

   drives the channel hardware unit, and the Network program which

   carries out the user's transmission requests.

   As the communication is full duplex, each of these programs can be

   viewed as divided into two parts: one is concerned with the output

   data, the other with the input. (See Fig. 1)

   These two programs exchange data through a pool of buffers, and

   logical information through an interface table.

   In the following we only focus on the output part of each program

   (See Fig. 2).  The input part would be very similar.

II-1.   Network program.

II-1-1. Multiplex function.

   This program multiplexes the outgoing messages (and distributes the

   incoming messages).  The multiplexing consists in stacking up all the

   user's (or caller, or party) requests and filling up the pool of

   buffers so as to keep the handler busy emitting.

   Multiplexing (and distribution) is based on the link identification

   numbers.  (Link = logical connection between two users).  The

   multiplexing problem is closely related to the interface between a

   user's program and the network program, that is in

   fact...(unreadable) operating system (See below: Questions).

II-1-2.  Output message processing.

   When a user's program wants to send out text it should indicate the

   following information (through a macro, or as call parameters): text

   location, text length in bytes, and destination.

Deloche                                                         [Page 2]

RFC 7                      Host-IMP Interface                   May 1969

   Using these data the Network program:

      *  prepares a 16 bit Host heading (1 bit: trace, 2 bits: spares, 8

         bits: link identification no., 5 bits: destination host)

      *  inserts a 16 bits marking between the header and the text so as

         to start the text at a word boundary.  This marking consists of

         a one preceding the first bit of the text and, in turn,

         preceded by fifteen zeros to fill up the gap.

      *  checks the length of the user's text - if it exceeds...