rfc2204.txt

中、英文RFC文档大全打包下载完全版 .

Network Working Group                                            D. Nash
Request for Comments: 2204                                        ODETTE
Category: Informational                                   September 1997


                     ODETTE File Transfer Protocol

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Abstract

   This memo describes a file transfer protocol to facilitate electronic
   data interchange between trading partners.

   The protocol, denoted the ODETTE File Transfer Protocol, supports
   both direct communication between installations and indirect
   communication via a third party clearing centre.  It was developed by
   the Organisation for Data Exchange by Tele Transmission in Europe to
   facilitate communication within the European motor industry and is
   presented here to allow for wider use within the Internet community.

Table of Contents

   1. Introduction                                               3
         1.1  -  Background                                      3
         1.2  -  Relationship to the original ODETTE Standard    3
         1.3  -  General Principles                              3
         1.4  -  Structure                                       4
         1.5  -  Virtual Files                                   4
         1.6  -  Service Description                             7

   2. Network Service (TCP Transport Service)                    7
         2.1  -  Introduction                                    7
         2.2  -  Service Primitives                              7
         2.3  -  Port Assignment                                 9

   3. File Transfer Service                                      9
         3.1  -  Model                                          10
         3.2  -  Session Setup                                  11
         3.3  -  File Transfer                                  13
         3.4  -  Session Take Down                              16
         3.5  -  Service State Automata                         19





Nash                         Informational                      [Page 1]

RFC 2204             ODETTE File Transfer Protocol        September 1997


   4. Protocol Specification                                    22
         4.1  -  Overview                                       22
         4.2  -  Start Session Phase                            22
         4.3  -  Start File Phase                               23
         4.4  -  Data Transfer Phase                            26
         4.5  -  End File Phase                                 27
         4.6  -  End Session Phase                              27
         4.7  -  Problem Handling                               28

   5. Commands and Formats                                      28
         5.1  -  Conventions                                    28
         5.2  -  Commands                                       29
         5.3  -  Command Formats                                29
         5.4  -  Identification Code                            45

   6. ODETTE-FTP Data Exchange Buffer                           46
         6.1  -  Overview                                       46
         6.2  -  Data Exchange Buffer Format                    46
         6.3  -  Buffer Filling Rules                           47

   7. Stream Transmission Buffer (TCP only)                     47
         7.1  -  Introduction                                   47
         7.2  -  Stream Transmission Header Format              49

   8. Protocol State Machine                                    50
         8.1  -  ODETTE-FTP State Machine                       50
         8.2  -  Error Handling                                 50
         8.3  -  States                                         51
         8.4  -  Input Events                                   53
         8.5  -  Output Events                                  54
         8.6  -  Local Variables                                55
         8.7  -  Local Constants                                55
         8.8  -  Session Connection State Table                 56
         8.9  -  Error and Abort State Table                    58
         8.10 -  Speaker State Table 1                          59
         8.11 -  Speaker State Table 2                          63
         8.12 -  Listener State Table                           65
         8.13 -  Example                                        68

   9.  Security Considerations                                  68

   Appendix A    Virtual File Mapping Example                   69
   Appendix B    ISO 646 Character Subset                       72

   Acknowledgements                                             73
   References                                                   73
   ODETTE Address                                               74
   Author's Address                                             74



Nash                         Informational                      [Page 2]

RFC 2204             ODETTE File Transfer Protocol        September 1997


1. Introduction

1.1  Background

   The ODETTE File Transfer Protocol (ODETTE-FTP) was defined in 1986 by
   working group four of the Organisation for Data Exchange by Tele
   Transmission in Europe (ODETTE) to address the electronic data
   interchange (EDI) requirements of the European automotive industry.
   It was designed in the spirit of the Open System Interconnection
   (OSI) model utilising the Network Service provided by the CCITT X25
   recommendation.

   Over the last ten years ODETTE-FTP has been widely deployed on
   systems of all sizes from personal computers to large mainframes.  As
   a result of the wide scale deployment of internet technology and the
   trend towards global business practices, ODETTE has decided to extend
   the scope of it's file transfer protocol to allow the use of TCP/IP
   and to make the protocol available to the Internet community.

   This memo describes the ODETTE-FTP protocol using the Transmission
   Control Protocol for it's network service.

1.2  Relationship to the original ODETTE Standard

   This memo is an interpretation of version 1.3 of the ODETTE File
   Transfer Protocol [OFTP].  In the event of any ambiguity between this
   document and the original ODETTE-FTP, the original shall take
   precedence.

   For ODETTE-FTP on TCP/IP the following sections have been added with
   respect to the original document.

      Section 2  - Network Service
      Section 7  - Stream Transmission Buffer
      Appendix A - Virtual File mapping example

1.3  General Principles

   The aim of the ODETTE-FTP is to facilitate the transmission of a file
   between one or more locations in a way that is independent of the
   data communication network, system hardware and software environment.

   In designing and specifying the protocol, the following factors were
   considered.

   1. The possible differences of size and sophistication (file storage,
      small and large systems).




Nash                         Informational                      [Page 3]

RFC 2204             ODETTE File Transfer Protocol        September 1997


   2. The necessity to work with existing systems (reduce changes to
      existing products and allow easy implementation).

   3. Systems of different ages.

   4. Systems of different manufactures.

   5. The potential for growth in sophistication (limit impact and avoid
      changes at other locations).

1.4  Structure

   ODETTE-FTP is modelled on the OSI reference model.  It is designed to
   use the Network Service provided by level 3 of the model and provide
   a File Service to the users.  Thus the protocol spans levels 4 to 7
   of model.

   The description of the ODETTE-FTP contained in this memo is closely
   related to the original 'X.25' specification of the protocol and in
   the spirit of the OSI model describes:

      1. A File Service provided to a user monitor.

      2. A protocol for the exchange of information between peer
         ODETTE-FTP entities.

   A major consideration in adapting the protocol to use the
   Transmission Control Protocol (TCP) was the desire to make no changes
   to the existing protocol by adding the functionality required to
   allow implementors to support internet communication with only minor
   changes to existing ODETTE-FTP engines.  To this end an additional
   header has been added to the start of each exchange buffer to allow
   the TCP byte stream to be broken up into the discrete exchange
   buffers expected by the ODETTE-FTP protocol.

1.5  Virtual Files

   Information is always exchanged between ODETTE-FTP entities in a
   standard representation called a Virtual File.  This allows data
   transfer without regard for the nature of the communicating systems.

   The mapping of a file between a local and virtual representation will
   vary from system to system and is not defined here.








Nash                         Informational                      [Page 4]

RFC 2204             ODETTE File Transfer Protocol        September 1997


                              o---------o
                         Site | Local   |
                          A   | File A  |
                              o---------o
                                   |
      o----------------------- Mapping A ------------------------o
      |                            |                             |
      |                       o---------o                        |
      |                       | Virtual |                        |
      |                       |  File   |                        |
      |                       o---------o                        |
      |    o------------------------------------------------o    |
      |    |                                                |    |
      |    |                  ODETTE-FTP                    |    |
      |    |                                                |    |
      |    o------------------------------------------------o    |
      |      o---------o                        o---------o      |
      |      | Virtual |                        | Virtual |      |
      |      |  File   |                        |  File   |      |
      |      o---------o                        o----+----o      |
      |           |                                  |           |
      o------ Mapping B ------------------------ Mapping C ------o
                  |                                  |
             o---------o                        o----+----o
             | Local   | Site              Site | Local   |
             | File B  |  B                 C   | File C  |
             o---------o                        o---------o

   A Virtual File is described by a set of attributes identifying and
   defining the data to be transferred.  The main attributes are:

1.5.1  Organisation:

   Sequential

      Logical records are presented one after another.  The ODETTE-FTP
      must be aware of the record boundaries.

1.5.2  Identification

   Dataset Name

      Dataset name of the Virtual File being transfered, assigned by
      bilateral agreement.







Nash                         Informational                      [Page 5]

RFC 2204             ODETTE File Transfer Protocol        September 1997


   Time stamp (HHMMSS)

      A file qualifier indicating the time the Virtual File was made
      available for transmission.

   Date stamp (YYMMDD)

      A file qualifier indicating the date the Virtual File was made
      available for transmission.

   The Dataset Name, Date and Time attributes are assigned by a Virtual
   File's Originator and are used to uniquely identify the file.  They
   must not be changed by intermediate locations.

   The Date attribute represents the decade and year in a two digit
   field.  Since the ODETTE-FTP only uses this information to identify a
   particular Virtual File it will continue to operate correctly in the
   year 2000 and beyond.

   The User Monitor may use the Virtual File Date attribute in local
   processes involving date comparisons and calculations.  Any such use
   falls outside the scope of this protocol and year 2000 handling is a
   local implementation issue.

1.5.3  Record Format

   Four record formats are defined.

      Fixed (F)

         Each record in the file has the same length.

      Variable (V)

         The records in the file can have different lengths.

      Unstructured (U)

         The file contains a stream of data.  No structure is defined.

      Text File (T)

         A Text File is defined as a sequence of ASCII characters,
         containing no control characters except CR/LF which delimits
         lines.  A line will not have more than 2048 characters.






Nash                         Informational                      [Page 6]

RFC 2204             ODETTE File Transfer Protocol        September 1997


1.5.4  Restart

   ODETTE-FTP can negotiate the restart of an interrupted Virtual File
   transmission.  Fixed and Variable format files are restarted on
   record boundaries.  For Unstructured and Text files the restart
   position is expressed as a file offset in 1K (1024 octet) blocks.
   The restart position is always calculated relative to the Virtual
   File.

1.6  Service Description

   ODETTE-FTP provides a file transfer service to a user monitor and in
   turn uses the Internet transport layer stream service to communicate
   between peers.

   These services are specified in this memo using service primitives
   grouped into four classes as follows:

      Request (RQ)       An entity asks the service to do some work.
      Indication (IND)   A service informs an entity of an event.
      Response (RS)      An entity responds to an event.
      Confirm (CF)       A service informs an entity of the response.

   Services may be confirmed, using the request, indication, response
   and confirm primitives, or unconfirmed using just the request and
   indication primitives.

2. Network Service (TCP Transport Service)

2.1  Introduction