ISO/IEC 7809:1993/Amd 10:1995

INTERNATIONAL lsO/lEc
STANDARD
Third edition
1993-12-15
AMENDMENT 10
1995-11-15
Information technology
- Telecommunications
and information exchange between Systems -
High-level data link control (HDLC) procedures -
Classes of procedures
AMENDMENT IO: Extension of HDLC sequence
number modulus beyond 128
Technologies de I ’information - T6kcommunications et behange d ’informations
entre systkmes - Prockdures de commande de liaison de donnbes 3 haut niveau
(HDLC) - Classes de procbdures
AMENDEMENT IO: Extension du module du numbro de skquence HDLC au-dela
de 728
Reference number
ISO/IEC 7809:1993/Amd.10:1995(E)

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ISO/IEC 7809:1993/Amd.10:1995(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the Inter-
national Electrotechnical Commission) form the specialized System for
worldwide standardization. National bodies that are members of ISO or
IEC participate in the development of international Standards through
technicai committees established by the respective organization to deal
with particuiar fields of technical activity. ISO and IEC technical
committees coiiaborate in fields of mutuai interest. Other international
organizations, governmentai and non-governmentai, in iiaison with ISO and
IEC, also take part in the work.
in the fieid of information technoiogy, ISO and IEC have established a joint
technicai committee, lSO/iEC JTC 1. Draft International Standards adopted
by the joint technical committee are circuiated to national bodies for
voting. Pubiication as an international Standard requires approval by at
least 75 % of the national bodies casting a vote.
Amendment 10 to International Standard iSO/IEC 7809:1993 was prepared
by Joint Technical Committee lSO/IEC JTC 1, Information technology,
Subcommittee SC 6, Telecommunications and information exchange
between s ystems.
0 ISO/IEC 1995
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Printed in Switzerland
ii

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ISO/lEC 7809:1993/Amd. 10:1995 (E)
0 ISOAEC
Introduction
This amendment to ISOAEC 7809:1993 increases the modulus number (i.e. the
sequence number) in Steps up to a maximum of 2 147 483 648 which tan be
represented in 31 bits. This is done by the introduction of a new “Set Mode” command
that tan be used to negotiate or indicate the modulus in absence of, or to override, a
default value. This uses an optional information field in the “Set Mode” command.
This amendment adds details necessary in extending the modulus beyond 128 and
also the introduction of the information field in the mode-setting commands/responses.
. . .
Ill

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0 ISOAEC ISO/IEC 7809:1993/Amd. 10:1995 (E)
nications and information exchange
High-level dalta link control (HDLC) procedures - Classes of
between Systems -
procedures
AMENDMENT 10: Extension of HDLC sequence number modulus beyond 128
Page 5
Subclause 3.4
Table 4
Renumber option 10 as 10.1 and add the following:
information field in DISC command with an optional
response frames a he DISC command information field
command with an optional information

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8 ilSo/IEe
:1993/Amd.10:1
subdause 3.4
Figure 5
Replace 18 as follows:
10 Extended sequence numbering
For extended sequence numbering, i.e., modulo 128 (not for UCC or BCC)
10.1
Use extended control field format instead of basic control field format; use
SXXME instead of SXXM.
10.2 For extended sequence numbering, i.e., modulo 32 768 (not for UCC or BCC)
Use the SM command.
10.3 For extended sequence numbering, i.e., modulo 2 147 483 648 (not for UCC or
BCC)
Use the SM command.
Page 6
Subclause 3.4
Figure 5
Add the following:
17 . For link set-up using Set Mode Command
Use the SM command in place of the corresponding frame from the basic
repertoire (SXXM) or the associated extended frame (SXXME).
18 . To convey information during acceptance of a link set-up, in a DM response,
and in the DISC command.
Use the optional information field in the UA,
...