RFC 7 (rfc7) - Page 2 of 7
Host-IMP interface
Alternative Format: Original Text Document
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