State of the art study on the standardisation of level 4

Directorate-General For Translation European Commission

Description

Transport layer of the ISO/TC97/SC16 reference model for open systems interconnection
Information technology and telecommunications

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• Publié par: EUROPEAN-COMMISSION
• Nombre de lectures: 6
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

EUR
Commission of the European Communities
information management
STATE OF THE ART STUDY
ON THE STANDARDIZATION OF LEVEL 4:
TRANSPORT LAYER OF THE ISO/TC97/SC16
REFERENCE MODEL FOR OPEN
SYSTEMS INTERCONNECTION
Report
EUR 7881 EN
Blow-up from microfiche original Commission of the European Communities
information management
STATE OF THE ART STUDY
ON THE STANDARDIZATION OF LEVEL 4:
TRANSPORT LAYER OF THE ISO/TC97/SC16
REFERENCE MODEL FOR OPEN
SYSTEMS INTERCONNECTION
FINAL REPORT
L. LENZINI
CNR-lstituto CNUCE, Pisa Italy
R. POPESCU-ZELETIN
HMI, Berlin, Germany
Chris A. VISSERS
Twente Univ., Enschede, Netherlands
Published by the Directorate-General
Information Market and Innovation
1982 EUR 7881 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Information Market and Innovation
Bâtiment Jean Monnet
LUXEMBOURG
LEGAL NOTICE
Neither the Commission of the European Communities nor any person
acting on behalf of the Commission is responsible for the use which might
be made of the following information
© ECSC-EEG-EAEC Brussels · Luxembourg 1982 III
CONTENTS
PREFACE iii
PART I: TUTORIAL 1
1 INTRODUCTION 2
2 THE ISO-OSI REFERENCE MODEL 3
Service
Protocol 4
Terminology and abbreviat ions 5
3 THE TRANSPORT LAYER 7
3.1 The Transport Service
3.1.1 Model used for service specification ....7
3.1.2 Transport Service Primitives.. ...9
Connection Oriented Services .
3.1.3 Cross reference between documents 12
3.2 Transport Protocols 16
3.2.1 Hierarchical Protocol Classes......7
3.2.2 Protocol Classes based on Protocol Options 21
4 COMPLIANCE WITH A STANDARD 23
4.1 Service and Protocol
User's and Manufacturer's perspective 25
4.2 Compliance checking of Service and Protocol
General 2
Service checking7
Need for Interface Standards?8
Compliance checking without Interface Standards 29
Protocolg 30
4.3 Certification efforts1
Standard Certification Entities
Certification Service Centers2
4.4 Service versus Protocol conflict
Realization characteristic of a Protocol... 34
Current situation on Service versus Protocol issue....35
4.5 Effect of layering5
4.6 Conclusions7
5 PRESENT SITUATION8
Political environment 3
Technical environment...'..... .39
Satellite Networks 42
Local Areas .4
PART II: ANALYSIS OF TRANSPORT SERVICES AND RELATED PROTOCOL
ISSUES5
6 INTRODUCTION TO TYPES OF TRANSPORT SERVICES 4Ó
6.1 Types of Transport Services&
6.2 Overview of part II 47 Ι V
7 ANALYSIS OF THE CONNECTION ORIENTED TRANSPORT SERVICE 4 8
7.1 Correctness and Completeness 49
7.1.1 Connectionidentification49
7.1.2 ntermination52
7.1.3 Options 53
7.1.4Typeparameter56
7.1.5Qualityof serviceparameters56
7.1.6Reasonparameter inDisconnect indication 57
7.1.7Flowcontrol59
7.2Architecturalconcerns61
7.3QualityofService enhancement.... 6.4
7.3.1Introduction64
7.3.2 Based on HierarchicalProtocols64
7.3.3 Based on Protocol Options68
7.3.4 Hierarchical Protocol vs.Optional Protocol70
7.4 Layer Management 72
7.5 Conclusions..75
8 TRANSACTIONORIENTEDSERVICES76
8.1 Fast Connect/DisconnectService76
Request/Response.77
8.2 ConnectionlessService78
Applicationswhichrequire Connectionless Service79
Technologiesthatdependon s Service....81
3
Reliable Datagram83
8.3 Conclusion on Transaction Services 83
9 HIGH BANDWIDTH NETWORKS 85
9.1 LocalAreaNetworkApplicationsand Services 85
9.2 SatelliteNetworks86
9.2.1SystemCharacteristics87
9.2.2SatelliteApplications and Services 87
9.3 Local AreaNetworksvsSatellite Networks
Protocolissues91
10 CONCLUSIONS 94
PARTIIIGENERALCONCLUSIONS9 5
11STRATEGICISSUESPER JUNE 198196
11.1Adequacyofthe isolation function 96
Nucleus.97
11.2 Types of Transport Service97
11.3 The Connection oriented TransportService98
11.4 The Convergence problem 99
Transport Service99tProtocols100
11.5 ConnectionlessTransport Service1C3
12 NUCLEUS FOR THE TRANSPORTSERVICE104
End-to-end compatibility105
APPENDIX 1 : MAPPING EXAMPLE 107
APPENDIX 2 : REFERENCES112PREFACE
This document is divided into three parts:
Part I gives a tutorial introduction and overview of the
relevant documentation concerning the subject of the study.
The material is presented without any attempt to prejudge it.
This part is intended to provide a common basis of
understanding for the discussions in the successive parts. In
addition it discusses the general problem of compliance to a
standard.
Part II provides a critical analysis of the State of the Art of
Transport Layer Services and related Protocol issues as by June
1981. To this end Part ÏI analyses not only the Connection
Oriented Transport Service, which at this moment forms the
prime concern of standardization within the Session and
Transport Working Group (WG6) of ISO/TC97/SC16, but places this
discussion in the wider context of other types of services
which are, or may be assumed to become, serious candidates for
Transport Level Services.
Part III summarizes the main strategic issues and related
conclusions, and provides guidelines for the definition of a
common nucleus for a Connection Oriented Transport Service.
How to read the document
The material in this document has been brought together In two
phases, following ISO TC97/SC16/WG6 meetings in November 1980
and June 1981. These phases are reflected in some of the
chapters.
The text of most chapters heavily leans on terminology, which
is current in 'Open Systems Interconnection' circles and might
present difficulties for the unfamiliar reader.
Therefore, the reader who isr with the subject under
discussion is adviced to read PART I first.
The reader who whishes to be informed with a short overview
about the current strategic issues is adviced to read PART III.
The reader who whishes to understand in more detail the
technical background for these issues is adviced to read PART
II. PAGE
PART I: TUTORIAL 1 INTRODUCTION PAGE
1 INTRODUCTION
During the last years much effort has been made in several
national and international standardization bodies (ISO, CCITT,
ANSI, ECMA) to develop abstract models for the design of
distributed systems . Intensive activities have been witnessed
in the area of Open Systems Interconnection (OSI), activities
which were supported by national standardization bodies to
promote international standards.
Their major motivation stems from the rapid emergence of public
networks (Europe, North America), local networks, and satellite
communication. To accommodate the different existent and
proposed technologies and strategies in these major fields a
Reference Model for Open Systems Interconnection was developed
within ISO/TC97/SC16, which is described in document N537.
The present status of this document in the form of a draft
proposal for standardization DP7498 is based on agreements
achieved in the last three years between specialists of the ISO
member bodies.
The Reference Model reflects a layered architecture. The future
standards for the Transport Layer, which fit in level 4, play
an important role in this model as they intend to separate the
Data Processing oriented functions from the Data Communication
oriented functions.