ISO/IEC ISP 10609-21:1995
(Main)Information technology — International Standardized Profiles TB, TC, TD and TE — Connection-mode Transport Service over connection-mode Network Service — Part 21: Subnetwork-type dependent requirements for Network Layer and Data Link Layer for ISDN B-channel X.25 DTE to DTE operation
Information technology — International Standardized Profiles TB, TC, TD and TE — Connection-mode Transport Service over connection-mode Network Service — Part 21: Subnetwork-type dependent requirements for Network Layer and Data Link Layer for ISDN B-channel X.25 DTE to DTE operation
Specifies the requirements for Network Layer and Data Link Layer that apply specifically to configurations involving access to an ISDN subnetwork for B-channel X.25 DTE to DCE operation (Semi-permanent or Circuit-mode service).
Technologies de l'information — Profils normalisés internationaux TB, TC, TD et TE — Service de transport en mode connexion sur service de réseau en mode connexion — Partie 21: Prescriptions dépendantes du type de sous-réseau pour la couche réseau et la couche liaison de données pour ISDN en opération sur DTE X.25 canal B à DTE
General Information
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Standards Content (Sample)
INTERNATIONAL ISB/IEC
STANDARDIZED
ISP
PROFILE 10609-21
First edition
1995-12-15
Information technology - International
Standardized Profiles TB, TC, TD and
TE - Connection-mode Transport Service
over connection-mode Network Service -
Part 21:
Subnetwork-type dependent requirements for
Network Layer and Data Link Layer for ISDN
B-channel X.25 DTE to DTE Operation
Technologies de I ’informa tion - Profils normalk& internationaux TB, TC,
TD et TE - Service de transport en mode connexion sur Service de
rkseau en mode connexion -
Partie 27: Prescriptions dbpendantes du type de sous-rbseau pour Ia
couche r&eau et Ia couche liaison de donnbes pour ISDN en Operation
sur DTE X.25 canal B 2 DTE
Reference number
ISO/IEC ISP 10609-21 :1995(E)
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ISO/IEC ISP 10609=21:1995(E)
Page
Contents
. . .
. . . . . . . . . . . . . .~.~.~. 111
Foreword
vi
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “.
1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “. 1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “. “~.~.~.~. 1
2 Normative references
2
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.~~. ”.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.~. 2
4 Abbreviations
........................................................................ 3
5 Subnetwork-type dependent requirements for the Network Layer
3
5.1 Static conformance requirements .
4
5.2 Dynamit conformance requirements .
...................................................................... 5
6 Subnetwork-type dependent requirements for the Data Link Layer
.................................................................................................... 5
6.1 Static conformance requirements
6.2 Dynamit conformance requirements . 5
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.~.~. 8
Annex A: ISPICS requirements list
8
A. 1 Introduction ,.,.~.
A.2 Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.~.~.~. 8
A.3 IPIU for ISO/IEC 8208 . . . . . . . . . . . . . . . . . . . . . . .*.*.~.~.*.~. 9
A.4 IPRL for ISO 7776 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
17
Annex B: Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .~.~.~.~.
B.1 Introduction . . . . . . . . . . . .~.~.~.~. 17
B.2 ISO/IEC 8208 recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “.~ 17
17
B.3 ISO 7776 recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Annex C: Guidance on the derivation of the value for N 1 . . . .~.~. ”. 18
OISO/IEC 1995
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any
means, electronie or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
ISO/IEC Copyright Office l Case postale 56 l CH-121 1 Geneve l Switzerland
Printed in Switzerland
ii
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0 ISO/IEC ISO/IEC ISP 10609=21:1995(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International 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 technical committees established by the respective
organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in
fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO
and IEC, also take part in the work.
In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
In addition to developing International Standards, ISOLIEC JTC 1 has created a Special Group on Functional
Standardization for the processing of International Standardized Profiles.
An International Standardized Profile is an internationally agreed, harmonized document which identifies a Standard
or group of Standards, together with Options and Parameters, necessary to accomplish a function
or set of functions.
Draft International Standardized Profiles are circulated to national bodies for voting. Publication as an International
Standardized Profile requires approval by at least 75% of the national bodies casting a vote.
International Standardized Profile ISOLIEC ISP 10609-21 was prepared with the collaboration of
- Asia-Oceania Workshop (AOW);
- European Workshop for Open Systems (EWOS);
- Open Systems Environment Implernentors’ Workshop (OIW).
ISOAEC ISP 10609 consists of the following Parts, under the general title Information technoloa - International
Standardized Profiles TB, TC, TD and TE - Connection-mode Transport Service over connection-mode Network
Service:
Part 1: Subnetwork-type independent requirements for Group TB
Part 2: Subnetwork-type independent requirements for Group TC
Part 3: Subnetwork-type independent requirements for Group TD
Part 4: Subnetwork-type independent requirements for Group TE
Part 5: Definition of profiles TBlll l/TBll21
Part 6: Definition of profiles TC1 11 MC112 1
Part 7: Definition of profiles TDlll l/TDll21
Part 8: De$nition of profiles TE1 11 l/TEll2 1
requirements for Network Layer, Data Link Layer and
Part 9: Subnetwork-type dependent Physical
Layer concerning permanent access to a packet switched data network using virtual calls
Part 10: LAN subnetwork-dependent, media-independent requirements
. . .
111
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ISO/IEC ISP 10609=21:1995(E)
0 ISO/IEC
Part 11: CSMAKD LAN subnetwork-dependent, media-dependent requirements
Part 12: Definition of Profile TCSl, Provision of the OSI connection-mode Transport Service using
the OSI connection-mode Network Service in an End System attached to a CSMA/cD LAN
Part 14: Definition of Profile TC53, Provision of the OSI connection-mode Transport Service using
the OSI connection-mode Network Service in an End System attached to a Token Ring LAN
Part 1.5: Definition of Profile TC54, Provision of the OSI connection-mode Transport Service using
the OSI connection-mode Network Service in an End System attached to an FDDI LAN
Part 20: Overview of the generalized multi-part ISP structure for TC and TD Group profiles for OSI
usage of ISDN
Part 21: Subnetwork-type dependent requirements for Network Layer and Data Link Layer for ISDN
B-channel X.2.5 DTE to DTE Operation
Part 22: Subnetwork-type dependent requirements for Network Layer and Data Link Layer for ISDN
B-channel X.25 DTE to DCE Operation
Part 23: Subnetwork-type dependent requirements for Network Layer and Data Link Layer for Data
Transfer concerning a packet switched mode Integrated Services Digital Network using virtual calls.
B-channel access case
Part 24: Subnetwork-type dependent requirements for Network Layer and Data Link Layer for Data
Transfer concerning a packet switched mode Integrated Services Digital Network using virtual calls:
D-channel access case
Part 25: Subnetwork-type dependent requirements for Q.931 circuit-switched Operation
Part 26: Subnetwork-type dependent requirements for Network Layer for Cal1 Control procedures
concerning the outgoing cal1 of a packet switched mode Integrated Services Digital Network in case
B using virtual calls
Part 27: Subnetwork-type dependent requirements for Network Layer for Cal1 Control procedures
concerning the incoming cal1 of a packet switched mode Integrated Services Digital Network in case
B using virtual calls
Part 28: Subnetwork-type dependent requirements for Data Link Layer for end Systems attached to
an ISDN subnetwork
Part 30: Definition of Profile TC1 13 1
Part 31: Definition of proflle TC1231
Part 32: Definition of Profile TC41 11
Part 33: Definition of Profile TC421 1
Part 34: Definition of Profile TC431 11
Part 35: Definition of Profile TC431 12
Part 36: Definition of Profile TC432 11
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0 ISO/IEC ISO/IEC ISP 10609=21:1995(E)
Part 37: Dejkition of Profile TC43212
Part 38: Definition of Profile TC4331
Part 40: Definition of procfile TDll31
Part 41: Definition of Profile TDl231
Part 42: Definition of Profile TD4111
Part 43: DeJinition of Profile TD4211
Part 44: Definition of Profile TD43111
Part 45: Definition of Profile TD43112
Part 46: Definition of projcile TD43211
Part 47: Definition of Profile TD43212
Part 48: Definition of Profile TD4331
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ISO/IEC ISP 10609=21:1995(E) 0 ISOIIEC
Introduction
This International Standardized Profile (ISP) is defined in accordance with the principles specified by ISO/IEC
Technical Report 10000, “Information technology - Framework and taxonomy of International Standardized
Profiles ”.
The context of Functional Standardization is one area in the Overall field of Information Technology (IT)
standardization activities, covering base Standards, profiles, and registration mechanisms. A Profile defines a
combination of base Standards that collectively perform a specific well-defined IT function. Profiles standardize
the use of Options and other variations in the base Standards, and provide a base for the development of uniform,
intemationally recognized System tests.
ISPs are produced not simply to “legitimize” a particular choice of base Standards and Options, but to promote
real System interoperability. One of the most important roles for an ISP is to serve as the basis for the
development (by organizations other than ISO and IEC) of intemationally recognized test methods. The
development and widespread acceptance of tests based on this and other ISPs is crucial to the successful
realization of this goal.
ISO/IEC ISP 10609 consists of several Parts of which this is part 2 1. This part of ISO/IEC ISP 10609 specifies
subnetwork-dependent and media-dependent requirements. There are further Parts which specifj/ Profile
requirements that are subnetwork-independent. In addition, for each individual profile there is a part of ISO/IEC
ISP 10609 which identifies the specific requirements of that Profile, making reference to appropriate material
from Parts 2 or 3, and from the subnetwork dependent Parts of ISO/IEC ISP 10609.
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INTERNATIONAL STANDARDIZED PROFILE 0 ISO/IEC ISO/IEC ISP 10609-21:1995tE)
International Standardized
Information technology -
Profiles TB, TC, TD and TE - Connection-mode
Transport Service over connection-mode Network
Service -
Part 21:
Subnetwork-type dependent requirements for Network Layer
and Data Link Layer for ISDN B-channel X.25 DTE to DTE
Operation
1 Scope
ISO/IEC ISP 10609 is applicable to end Systems concemed with operating in the Open Systems Interconnection
(OSI) environment. It specifies a combination of OS1 Standards, which collectively provide the connection-mode
Transport Service using the connection-mode Network Service.
This part of ISO/IEC ISP 10609 specifies the requirements for Network Layer and Data Link Layer that apply
specifically to configurations involving access to an ISDN subnetwork for B-channel X.25 DTE to DTE
Operation (Semi-permanent or Circuit-mode Service).
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this
part of ISO/IEC ISP 10609. At the time of publication, the editions indicated were valid. All documents are
subject to revision and Parties to agreements based on this part of ISO/IEC ISP 10609 are wamed against
automatically applying any more recent editions of the documents listed below, since the nature of references
made by ISPs to such documents is that they may be specific to a particular edition. Members of IEC and ISO
maintain registers of currently valid International Standards and ISPs, and ITU-T maintains published editions of
its current Recommendations.
ISO/IEC 7776: 1995, Information technology - Telecommunications and information exchange between Systems -
High-level data Zink control procedures - Description of the XI 25 LAPB-compatible DTE data Zink procedures.
ISO/IEC 8208: 1995, Information technology - Data communications - X.25 Packet Layer Protocol for Data
Terminal Equipment.
ISO/IEC 8348: 1993, Information technology - Open Systems Interconnection - Network Service Definition.
1
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0 ISO/IEC
ISO/IEC ISP 10609=21:1995(E)
NOTE - ISO/IEC 7776: 1995, ISO/IEC 8208: 1995 and ISO/IEC 8348: 1993 supersede ISO 7776: 1986, ISO/IEC 8208: 1990
and ISO 8348: 1987 respectively. However, when this part of ISO/IEC ISP 10609 was under development, the previous
editions were valid and this part of ISO/IEC ISP 10609 is therefore based on these editions. The new editions give extensions
and incorporate all of the amendments and corrigenda to the previous editions, which are listed below.
- High-level data link control procedures -
ISO 7776: 1986, Information processing Systems - Data communications
Description of the X.2.5 LAPB-compatible DTE data linkprocedures.
ISO 7776: 1986Kor. 1: 1989, Information processing Systems - Data communications - High-level data link control
Description of the X.2.5 LAPB-compatible DTE data link procedures - Technical Corrigendum 1.
procedures -
ISO 7776: 1986Kor.2: 1989, Information processing Systems - Data communications - High-level data link control
Description of the X.2.5 LAPB-compatible DTE data link procedures - Technical Corrigendum 2.
procedures -
ISO 7776: I986lCor.3: 199 1, Information processing Systems - Data communications - High-level data link control
procedures - Description of the X.25 LAPB-compatible DTE data linkprocedures - Technical Corrigendum 3.
ISO/IEC 7776: 1986lAmd. 1: 1992, Information technology - Information processing Systems - High-level data link control
Description of the X.25 LAPB-compatible DTE data link procedures - Amendment 1: Conformance
procedures -
requirements.
ISO/IEC 8208: 1990, Information technology - Data communications - X.25 Packet Layer Protocol for Data Terminal
Equ2pment (see also CCITT Recommendation X 25-1988).
ISO/IEC 8208: 1990knd.3: 199 1, Information technology - Data communications - X.25 Packet Layer Protocol for Data
Terminal Equipment - Amendment 3: Conformance requirements.
- X.25 Packet Layer Protocol for Data
ISO/IEC 8208: 1990Kor. 1: II 992, Information technology - Data communications
Terminal Equipment - Technical Corrigendum 1.
ISO 8348: 1987, Information processing Systems - Data communications - Network Service definition (see also CCITT
Recommendation X.213-1988).
ISO 8348: 1987lAdd.2: 1988, Information processing Systems - Data communications - Network Service definition -
Addendum 2: Network layer addressing (see also CCITT Recommendation X 213-1988).
ISO/IEC 8878: 1992, Information technology - Telecommunications and information exchange between Systems -
Use of XI 2.5 to provide the OS1 Connection-mode Network Service.
ISO/IEC 9574: 1992, Information technology - Provision of the OS1 connection-mode network Service by packet
mode terminal equipment connected to an integrated Services digital network (ISDN).
3 Definitions
The terms used in this part of ISO/IEC ISP 10609 are defined in the referenced base Standards (see clause 2).
4 Abbreviations
The following abbreviations are used in this part of ISO/IEC ISP 10609:
AEF Address Extension Facility
BCD Binar-y Coded Decimal
Data Circuit-terminating Equipment
DCE
DTE Data Terminating Equipment
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0 ISO/IEC ISO/IEC ISP 10609=21:1995(E)
HIC Highest Incoming Channel
HOC Highest Outgoing Channel
HTC Highest Two-way Channel
IPRL ISPICS Requirements List
ISDN Integrated Services Digital Network
ISP International Standardized Profile
ISPICS ISP Implementation Conformance Statement
LIC Lowest Incoming Channel
LOC Lowest Outgoing Channel
LTC Lowest Two-way Channel
LAPB Link Access Protocol Balanced
NSAP Network Service Access Point
OS1 Open Systems Interconnection
PICS Protocol Implementation Conformance Statement
SABM Set Asynchronous Balanced Mode
SABME Set Asynchronous Balanced Mode Extended
SDL Specification and Description Language
vc Virtual Cal1
XID exchange Identification
5 Subnetwork-type dependent requirements for the Network Layer
51 . Static conformance requirements
5.1.1 Overall requirements
An implementation conforming to this part of ISO/IEC ISP 10609 shall:
a meet the static conformance requirements specified in clause 17 of ISO/IEC 820WAmd. 3;
0
meet the additional static conformance requirements for ISO/IEC 8208, as constrained by ISO/IEC 8878,
0
in subclause 5.1.2 below;
C implement all the features identified as requirements in the ISPICS requirements list in annex A.
0
5.1.2 Additional static conformance requirements
a If an end System operates more than one B-channel connection with one or more than one other end
0
System, the packet layer of each B-channel connection shall be processed independently ft-om the packet
layer of each other B-channel connection (e.g. DTE/DCE role assignment, logical channel range, etc.).
The procedures defined in ISO/IEC 8878, subject to any additional requirements defined in the remainder
0
of subclause 5.1.2, shall be used to support the OS1 connection-mode Network Service over each X.25
virtual call.
multiple B-channels, each Network Service
NOTE - Although the Network Service may be provided over
connection is independent and uses only one of these B-channels. In general, the Network Service user is
not explicitly aware of the number of B-channels supporting the Network Service.
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0 ISO/IEC
ISO/IEC ISP 10609=21:1995(E)
C The end System shall be capable of adopting the role of a DTE or a DCE at the packet layer.
0
The DTE or DCE role shall be either :
agreed for a period of time, or;
0
ii) determined by the Restart procedure described in ISO/IEC 8208
NOTE - Both Options i) and ii) above may be implemented in a Single System.
Only two way VCs shall be provided by an end System. Consequently, only values of Parameters LTC
(Lowest Two way channel) and HTC (Highest Two way Channel) from ISO 8208/IEC shall be defned.
e The value of LTC shall be 1.
0
The minimum value for HTC shall be 1.
(0
If additional logical channels are required and a DTE is capable of initiating a Registration Request
(9)
packet, then the Registration Parameter Felds shall be set as follows :
The LIC, HIC, HOC, LOC Parameters shall be set to Zero. The LTC shall be set to the value 1. The value
in the total number of logical channels Parameter field shall be set equal to value in the HTC Parameter
field.
No other Optional User Facilities shall be identified in the Registration Request packet, and may be
ignored by a responder if they are present.
If a DTE is capable of responding with a Registration Confirmation packet, the maximum number of two
way logical channels allowed between the two DTEs shall be indicated in the HTC Parameter field. The
value in the HTC Parameter field shall be less than or equal to the value requested in the HTC field in the
Registration Request packet.
Registration of facilities normally applies in one direction only for the DTE/DTE case (i.e. registration of
facilities is performed independently for each direction), but for the logical channel range negotiation it
applies to both directions.
NOTE - Registration Request packets may be ignored by a responder. However, it is recommended that DTEs are
capable of responding with a Registration Confirmation packet even if they only support a Single two-way
logical channel. This will prevent unnecessary delays for the initiator in transmitting a Cal1 Request packet.
Such delays are determined by the initiator ’s values for Timer T28 and retry counter R28.
The end System shall indicate “no restriction on response” when using the fast select facility.
00
i Non-use of expedited data shall be negotiated when transport protocol class 0 or class 2 is used.
0
.
The Receipt Confirmation Service is not supported. The D-bit shall always be set to 0. If a conforming
0)
implementation receives a DATA packet with the D-bit set to 1, then it is recommended to clear the
logical channel with a Cause indicating “DTE Originated” and with the diagnostic “D-bit Procedure Not
Supported (Code 166) “.
4
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0 ISOIIEC ISO/IEC ISP 10609=21:1995(E)
Encoding of the calling, called and responding NSAP addresses in the address extension fields of cal1
(k)
setup and clear packets shall be as specified in ISO/IEC 8878 for explicitly conveying the full NSAP
address.
NOTE - Included in these requirement is implementation of the Address Extension Facility (AEF) to carry up to a
4O-digit NSAP Address. Furthermore, for the AEF, “split” NSAP addresses, previously allowed in
ISO/IEC 8208, are prohibited whereas non-BCD information, previously prohibited in ISO/IEC 8208, is
allowed.
52 . Dynamit conformance requirements
Overall requirements
5.2.1
An implementation conforming to this part of ISO/IEC ISP 10609 shall:
implement the packet layer protocol procedures as described in ISO/IEC 8208 for DTE/DTE Operation;
a
0
behave in accordance with the requirements of the ISPICS requirements list in annex A.
Additional dynamic conformance requirements
5.2.2
NSAP address:
The System shall support all the formats and syntaxes defined in ISO/IEC 8348/Add. 2. A conforming
implementation shall handle NSAP Address as defined in ISO/IEC 8878. The use of CalledKalling Address
Extension Facilities is preferred for conveying the NSAP Address even when the three conditions described in
ISO/IEC 8878, subclause 6.2.2.1.1 are satisfied.
6 Subnetwork-type dependent requirements for the Data Link Layer
61 . Static conformance requirements
Overall requirements
6.1.1
An implementation conforming to this part of ISO/IEC ISP 10609 shall:
a meet the static conformance requirements in accordance with ISO 7776/Amd. 1;
0
meet the additional static conformance requirements for ISO 7776 in subclause 6.1.2 below;
w
C implement all the features identified as requirements in the ISPICS requirements list in annex A.
0
Additional static conformance requirements
6.1.2
(a) Only the Single Link Procedure shall be supported.
An independent LAPB protocol shall operate over each B-channel.
09
Parameter NI (maximum number of bits in an 1 frame) shall be such that the Data Link layer is capable
C
0
of carrying the maximum packet size negotiated at the packet layer, plus the related packet layer and Data
Link layer control information. Guidance on the derivation of the value of N 1 tan be found in annex C.
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ISO/IEC ISP 10609-21:1995(E) 0 ISO/IEC
The end System which is assigned the Station address “A” shall be responsible for setting up and
w
disconnecting the Data Link, but the other end System may also do it.
e If the extended Operation is implemented, and is preferred, the actual mode of Operation shall either :
0
i) be agreed for a period of time; or
ii) be negotiated on a “per link” basis using the procedure detailed in subclause 6.2.
62 . Dynamit conformance requirements
6.2.1 Overall requirements
An implementation conforming to this part of ISO/IEC ISP 10609 shall:
a implement the procedures as described in ISO 7776 for DTE/DTE Operation;
0
meet the additional dynamic conformance requirements for ISO 7776 in subclause 6.2.2 below;
(b)
C behave in accordance with the requirements of the ISPICS requirements list in annex A.
0
NOTE - If it is desired to interwork with Systems using CCITT Recommendation T.90, it should be noted that CCITT T.90
describes three alternative methods of layer 2 modulo negotiation:
1. SABME and SABM on B-channel
2. XID
3. Outbound mechanism using LLC information element on D-channel
6.2.2 Additional dynamic conformance requirements
the layer 2 modulo when negotiation
The diagram shown in figure 1 indicates the method for determining the
for a parti cular conn ection
mechanism for the extended Operation is implemented, and is required
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ISOIIEC ISP 10609=21:1995(E)
0 ISO/IEC
r
Rese t
Counter
I
I
Tl timeout
Tl timeout
Counter <> N2 Counter = N2
i l I
Operation 0s
Increment
per ISO 7776
Counter
I
Tl iimeout
1
L
0
Informotion
~q;mf&;dPhose
Ober0 tion
Basic Opero tion
Figure 1 - SDL diagam for the layer 2 modulo negotiation mechanism
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0 ISO/IEC
ISO/IEC ISP 10609=21:1995(E)
Annex A
(normative)
ISPICS requirements list
Introduction
A.1
The IPRLs in this annex specify requirements for implementation of the Network Layer and Data Link Layer.
The Network Layer IPRL in clause A.3 specifies the additional requirements for ISO/IEC 8208/Amd.3. The
requirements of ISO/IEC 8208/Amd.3 apply to each item for which there is no entry in the IPRL (clause A.3).
These IPRLs specify subnetwork dependent requirements for an end System attached to an ISDN subnetwork for
B-channel X.25 DTE to DTE Operation.
A conforming implementation shall satisfy the mandatory conformance requirements of the base Standards
referenced in this part of ISO/IEC ISP 10609.
Notation
A.2
The following Symbols are used to identify the capabilities to be supported by a conforming implementation:
Base Standard Status notation
a>
Standard Type or Range:
M mandatory
0 optional
O. optional, but at least one of the group of Options labelled by the same numeral is required;
not applicable
pred: conditional item Symbol, including predicate identification
pred: : this group predicate Symbol applies to the Status of each of the items that follows, until another
such group predicate occurs or until the next horizontal rule separating groups of items. The
items are only completed when the predicate is true.
IPRL Status notation
b)
The Status column of Profile features is entered using the one Character or the two Character notation. The
one Character notation indicates the static conformance requirements only. For the two Character notation,
the first Character indicates the static conformance requirements and the second indicates the dynamic
conformance requirements.
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0 ISO/IEC ISO/IEC ISP 10609921:1995(E)
Static:
1)
m mandatory, mandatory to be implemented
0 optional, optional to be implemented
o. optional, but at least one of the group of Options labelled by the same numeral is required
i out of scope, not relevant to this Profile.
Dynamit:
2)
m mandatory, mandatory to be used
X excluded, prohibited to be used in the context of this Profile.
A.3 IPRL for ISO/IEC 8208
The relevant base Standard PICS proforma is given in annex B of ISO/IEC 82OWAmd.3. This part of ISO/IEC
ISP 10609 imposes the following constrai
...
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