ISO 8878:1987/Add 2:1990

Information processing systems — Data communications — Use of X.25 to provide the OSI connection-mode network service — Addendum 2

Systèmes de traitement de l'information — Communication de données — Utilisation du protocole X.25 pour fournir le service de réseau OSI en mode connexion — Additif 2

General Information

• Status: Withdrawn
• Publication Date: 19-Jun-1990
• Withdrawal Date: 19-Jun-1990
• ICS: 35.100.30 - Network layer
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 30-Dec-1992

Relations

• Amends: ISO 8878:1987 - Information processing systems — Data communications — Use of X.25 to provide the OSI connection-mode network service
• Effective Date: 06-Jun-2022
• Child: ISO 8878:1987 - Information processing systems — Data communications — Use of X.25 to provide the OSI connection-mode network service
• Effective Date: 18-Dec-2008

Standards Content (Sample)

IS0
INTER NATIONAL
STANDARD
First edition
1987-09-01
ADDENDUM 2
1990-06-1 5
Information processing systems - Data
communications - Use of X.25 to provide the
OS1 connection-mode network service
ADDENDUM 2: Use of an X.25 PVC to provide the
OS1 CONS
Systèmes de traitement de l'information - Communication de données -
Utilisation du protocole X.25 pour fournir le service de réseau OS1 en mode
connexion
ADDITIF 2: Utilisation d'un PVC X.25 POUT fournir l'OS1 CONS
Reference number
IS0 8878 : 1987/Add.2 : 1990 (E)

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IS0 8878 : 1987/Add.2 : 1990 (E)
Foreword
IS0 (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized system for worldwide standardiz-
ation. National bodies that are members of IS0 or IEC participate in the development
of International Standards through technical committees established by the respective
organization to deal with particular fields of technical activity. IS0 and IEC technical
committees collaborate in fields of mutual interest. Other international organizations,
governmental and non-governmental, in liaison with IS0 and IEC, also take part in the
work.
IS0 and IEC have established a joint technical
In the field of information technology,
committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint
technical committee are circulated to national bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the national bodies casting
a vote.
Addendum 2 to IS0 8878: 1987 was prepared by Joint Technical Committee ISO/IEC
1, Information technology.
JTC
0 ISO/IEC 1990
All rights reserved. No part of this publication may be reproduced or utilized in any form or by any
means, electronic or mechanical, including photocopying and microfilm, without permission in
writing from the publisher.
ISO/IEC Copyright Office O Case postale 56 0 CH-I211 Genève 20 0 Switzerland
Printed in Switzerland
ii

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IS0 8878 : 1987/Add.2 : 1990 (E)
Information processing systems - Data communications
- Use of X.25 to provide the OS1 connection-mode
network service
ADDENDUM 2: Use of an X.25 PVC to provide the OS1 CONS
1. Clause O, Paragraph 1 , Line 1 : Delete "two".
2. Clause O, Paragraph 1, Line 2: Insert the words "Virtual Call (VC) and Permanent Virtual
Circuit (PVC) services of the" before "X.25 Packet Level Protocol."
3. Clause O, Paragraph 1, Line 2: Change the first three words to "For VCs, one method,
which is presented. . .I1
4. Clause O, Paragraph 1, Line 4: Change "The second method" to "A second method for
VCS,"
5. Clause O: Add the following new paragraph after Paragraph 7:
Annex F defines the method for providing the OS1 CONS in conjunction with the
PVC service of X.25. Annex F is a normative pari of this International Standard.
6. Clause 1 , Paragraph 1, Line 5: Add the following sentence after II. . .(Annex A)."
These mappings apply to the X.25 VC service.
7.
Clause 1 : Add the following new paragraph after Paragraph 1 :
For the PVC service for both the X.25/PLP-1984 and the X.25/PLP-1980, a
mapping of CONS primitives and parameters to the X.25/PLP is given in Annex F.
8. Clause 4.3: Add the following to the list of abbreviations:
PVC Permanent Virtual Circuit
Clause 5.1 : Extend Paragraph 2 by adding the following:
in Clauses 6 and 7 (the corresponding mapping for PVCs is given in Annex F).
1 o. Add Annex F as provided on the following pages.
1

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IS0 8878 : lW/Add.2 : 1990 (E)
ANNEX F
Subnetwork Convergence Protocol For Use With X.25 Perinanent Virtual Circuits
This annex is normative.
F.0 Introduction and scope
This annex defines a set of SNDCP procedures for use with X.25 Permanent Virtual Circuit
(PVC) service for X.25-1980 and later versions. These procedures provide:
a) a mechanism for transferring data during the "connection establishment" and "connection
I
release" phases of a Network Connection;
l
b) a method for transferring NSAP Addresses;
c) association of QOS characteristics with the PVC; and
d) a method for selecting use of the Receipt Confirmation and Expedited Data options.
With the use of the procedures in this annex, a PVC can be used to provide the CONS for
different NCs, with the same or different parameter values, at different times.
This annex specifies the procedures for use by an End System: he PVC can connect the End
System either to another End System or to an Intermediate Syste In . This annex allows for the
possibility of using a PVC in support of other protocols, but 'not simultaneously with the
procedures of this annex (apart from transient collision cases, which do not fail unnecessarily).
F.l Overview
The procedures defined in this annex provide a mechanism for using X.25 PVC service in
support of the OS1 CONS. These procedures make up for the lack of dynamic mechanisms
visible to the NS user for NC establishment and release. No special1 procedures are defined here
for the data transfer phase.
The procedures in this annex make use of the packets, packet ;fields, and states associated
with the X.25 Virtual Call (VC) service. The "images" of these packets (i.e., "packet images") are
encoded within X.25 DATA packets. The states associated with the VC service are considered
as substates within state dl.
Two timers and one retransmission counter are specified for the SNDCP procedures: the
Connect Response Timer, the Disconnect Response Timer, and the Disconnect Retransmission
Counter. The procedures for use, and the default values, of these are the same as those for
I
T21, T23, and R23, respectively, in IS0 8208.
F.2 Abbreviations
The abbreviations given in the main body of this International Standard apply, with the
following additions:
Q-bit Qualifier bit
SNDCP Subnetwork Dependent Convergence Protocol
F.3 Protocol mechanisms
F.3.1 NC establishment procedure
The mapping of primitives/parameters used during the NC Establishment phase to packet-
images/fields is given below.
a) An N-CONNECT request primitive and the associated parameters are mapped to a CALL
REQUEST packet-image and the associated fields, as specified in clause 6 of the main
body of this International Standard.
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IS0 8878 : 1987/Add.2 : 1990 (E)
NOTE - The NL entity considers the QOS aspects (e.g., throughput) that were associated with the
PVC, when it was established, in relation to the QOS parameters of the N-CONNECT
request primitive (see 6.2.5). For example, if the Lowest Quality Acceptable Throughput
of an N-CONNECT request primitive is greater than the throughput class of a particular
PVC, then that PVC shall not be used for the associated NC.
b) This CALL REQUEST packet-image is sent to the remote NL entity in an M-bit Sequence
(MBS) of one or more DATA packets. The Q-bit in all DATA packets of the MBS shall be
set to 1. The Connect Response Timer shall be started. The timer is normally terminated
when the connection establishment is completed. If the timer expires, then the connection
shall be disconnected (see F.3.2).
c) An MBS of one or more DATA packets with its(their) Q-bit set to 1 and recognized as an
INCOMING CALL packet-image is mapped to an N-CONNECT indication primitive and the
associated parameters, as described in clause 6 of the main body of this International
Standard.
d) The equivalent procedure is applied to an N-CONNECT response primitive and CALL
ACCE
...