Browse Prior Art Database

Header for Messages within a Computer Network

IP.com Disclosure Number: IPCOM000077378D
Original Publication Date: 1972-Jul-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 3 page(s) / 24K

Publishing Venue

IBM

Related People

Seroussi, SF: AUTHOR [+2]

Abstract

The development of computer networks (networks of heterogeneous computing entities) has produced the need for an efficient computing entity line protocol which can handle interactive communications therebetween. To effect such communications, there is required a flexible line protocol.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Header for Messages within a Computer Network

The development of computer networks (networks of heterogeneous computing entities) has produced the need for an efficient computing entity line protocol which can handle interactive communications therebetween. To effect such communications, there is required a flexible line protocol.

There is disclosed herein a basic element of such line protocol, i.e., a message header. This message header is the only carrier of information through the network and as such is the foundation upon which all network transactions are effected.

The header comprises a plurality of well-defined fields, each of these fields providing an essential link within the protocol. In the figure there is shown an embodiment of a message header according to this disclosure. The header in the example shown suitably has a 96-bit width. The various fields therein are legended with individual mnemonics. The full names of the fields and their functions are set forth hereinbelow. Action Code 1 (AC1).

The function of this code is to indicate the line control options available between two computing entities or nodes within the network. It denotes that a node has performed a specific action on the line and that a response may or may not be required, depending on the function specified in the received message. This field is interpreted and modified by the communications interface, and together with the next adjacent field, TBN1 (TRANSMISSION BLOCK NUMBER
1) constitutes the line control message. An error in this field elicits an appropriate response from the interface.

In the situation of a communication with the adjacent node, the field can also indicate an end-to-end reply. In other words, it also functions as a logical control. Transmission Block Number 1 (TBN1).

The transmission block number is a field which is maintained by receiving stations to indicate, as part of a reply, the sequence number of the last message received. The main function of this field is to provide a check on the exchange of transmissions between adjacent nodes, in order to avoid the loss of messages. An error in this field causes the proper control message to be sent by the recipient thereof. Transmission Block Number 2 (TBN2).

This field is maintained and updated by the interface. It is employed as a sequence number and inserted into all outgoing messages which function, together with field TBN1, is to check for proper message order. As a message passes through the various nodes in the network to its final destination, both of fields TBN1 and TBN2 are overlayed by the corresponding values in each node. Action Code 2 (AC2).

This code indicates a logical function which is being exchanged. It...