ISO 8878:1987/Add 1:1990

Information processing systems — Data communications — Use of X.25 to provide the OSI connection-mode network service — Addendum 1

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 1

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• Status: Withdrawn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
8878
STANDARD
First edition
1987-09-01
ADDENDUM 1
1990-06-1 5
Information processing systems - Data
communications - Use of X.25 to provide the
OS1 connection-mode network service
ADDENDUM 1 : Priority
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 1: Priorité
Reference number
IS0 8878 : 1987/Add.l : 1990 (E)

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IS0 8818 : 1987/Add.l : 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,
IS0 and IEC, also take part in the
governmental and non-governmental, in liaison with
work.
In the field of information technology, IS0 and IEC have established a joint technical
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 1 to IS0 8878: 1987 was prepared by Joint Technical Committee ISOIIEC
JTC 1, Information technology.
O 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.
ISOllEC Copyright Office 0 Case postale 56 0 CH-I211 Genève 20 Switzerland
Printed in Switzerland
ii

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IS0 8878 : IW/Add.l : 1990 (E)
Information processing systems - Data communications
- Use of X.25 to provide the OS1 connection-mode
network service
ADDENDUM 1 : Priority
In trod uction
IS0 8878 specifies how to map between the elements of the Network Service Definition (IS0
8348) and the X.25 Packet Layer Protocol (PLP). îS0 8348/Add. 3 specifies that Quality of
Service (QOS) parameters for priority are to be added to those parameters subject to a three-
party negotiation/indication mechanism involving the Network Service provider and the two
Network Service users. This addendum to IS0 8878 specifies how to map between these
parameters and the corresponding elements of the X.25/PLP. It assumes the use of the Priority
Facility to be included in the second edition of IS0 8208 (corresponding to X.25-1988).
This Addendum is structured as a set of changes to IS0 8878. Several miscellaneous
changes are specified to alter the existing text in IS0 8878. The principal additions are new
subclause 6.2.5.3 for priority and a new Annex H.
1 Changes to IS0 8878:1987
1.1 Page 1, Clause O, Paragraph 1 :
- Lines 3-4: Change "elements of the 1984 .( X.25/PLP-1984)" to "elements of the 1984
or later versions of the X.25/PLP (referred to as X.25/PLP-1984)"
- Line 4: After "OS1 CONS.", add a new sentence as follows: "Features associated with
versions of X.25 later than 1984 are identified as to which version they relate."
- Line 6: Change "the 1980 version of the X.25/PLP." to "the 1980 or earlier versions of
the X.25/PLP (referred to as X.25/PLP-1980)."
1.2 Page 3: Add to the list of references:
IS0 8348/Add. 3, Information processing systems - Data communications - Network
Service Definition -Addendum 3: Additional features of the network service
1.3 Page 7, Item b above Clause 5.2:
- Bullet 4: delete "and"
- Bullet 5: change the period to a comma followed by "and"
- Add Bullet 6 as follows:
Priority (facility used, with 1988 or later versions of the X.25/PLP).
1.4 Page 9, Table 2: Add the following to the X.25/PLP-1984 column on the row dealing with
QOS-Parameter set:
Priority Facility
1.5 Page 11, Clause 6.2.5:
Line 1 : change "three" to "the following"
First Item b: delete "and"
First Item c: change the period to a semi-colon
f as follows:
Add items d through
d) the priority of the data transferred on the NC (with respect to data transferred on
other NCs);
1

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IS0 8878 : 1987/Add.l : 1990 (E)
e) the priority of gaining an NC; and
1) the priority of keeping this NC.
- tine 6: Delete "three"
1.6 Page 11, Clause 6.2.5.1 :
- Paragraph 2, Line 2: Change "48000" to "640001"
- Paragraph 2, Line 3: Change "and 48000" to "48000, and 64000"
- Add a Footnote 1 at the bottom of the page as follows:
1. A throughput of 64000 bits per second is available only for 1988 or later
versions of the X.25/PLP. For earlier versions, the highest throughput
available is 48000 bits per second.
2 Addltlon of new clause and annex
2.1 New subclause 6.2.5.3, page 2
6.2.5.3 Priority QOS parameters
The Priority Facility of the X.25iPLP is mapped to/from the three Priority QOS parameters of
N-CONNECT primitives.
The set of values that can be specified for each Priority subparameter ranges from O (lowest
priority) to 14 (highest priority). An NL entity supports all of these values. The value
"unspecified" is also allowed (encoded as 255 in the X.25/PLP).
6.2.5.3.1 Processing an N-CONNECT Request primitive
An NL entity that supports a choice of priority levels shall proceed as specified in 6.2.5.4.1 .l.
An NL entity that does not support a choice of levels shall proceed as specified in 6.2.5.4.1.2.
6.2.5.3.1.1 Processing with choice of levels supported
if an NL entity, when receiving an N-CONNECT request primitive, cannot support the Lowest
it
Quality Acceptable priority for any of the three Priority QOS parameters, when specified, then
rejects the request. In this case, the NL entity does not transmit any X.25iPLP packet but it does
signal an N-DISCONNECT indication primitive to the Calling NS user. The originator parameter
"NS Provider." The Reason parameter is "Connection Rejection - QOS Not
is
- QOS Not AvailablePermanent
Availableflransient Condition," or "Connection Rejection
if the NL entity could never support the Lowest Quality Am@able priority for one or
Condition"
more of the Priorily QOS parameters.
If an NL entity, when receiving an N-CONNECT request primitive, can support the Lowest
Quality Acceptable priority for all three Priority QOS parameters, when specified, or any of the
Lowest Quality Acceptable Priority QOS parameters is unspecified, then the NL entity encodes
the Priority Facility as follows:
a) ii the Lowest Quality Acceptable priority of a Priority parameter is specified, its value is
encoded in the subfield of the X.25/PLP Priority Facility desgnated to contain this
subparameter; otherwise, this subfield of the facility is encoded as 2 55 (unspecified); and
b) if the Target of a Priority parameter is specified, its value is encoded in the subfield of the
X.25iPLP Priority Facility designated to contain this subparameter; othemke, this
...