Proposed Federal Information Processing Standard: Specification for message format for computer based message systems
RFC 806

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Network Working Group
Request for Comments: 806

      
      Proposed Federal Information Processing Standard

      SPECIFICATION FOR MESSAGE FORMAT FOR 
      COMPUTER BASED MESSAGE SYSTEMS

      National Bureau of Standards
      Institute for Computer Sciences and Technology

      September 1981

      

      
      
      

      
      





                              TABLE OF CONTENTS

                                                                   Page

      EXECUTIVE SUMMARY                                               1

      1.  INTRODUCTION                                                3

          1.1  Guide to Reading This Document                         3
          1.2  Vendor-Defined Extensions to the Specification         4
          1.3  The Scope of the Message Format Specification          4
          1.4  Issues Not Within the Scope of the Message Format      4
               Specification
          1.5  Relationship to Other Efforts                          5

      2.  A SIMPLE MODEL OF A CBMS ENVIRONMENT                        6

          2.1  Logical Model of a CBMS                                8
          2.2  Relationship to the ISO Reference Model for Open      10
               Systems Interconnection
          2.3  Messages and Fields                                   10
          2.4  Message Originators and Recipients                    11

      3.  SEMANTICS                                                  12

          3.1  Semantics of Message Fields                           12
               3.1.1  Types of fields                                12
               3.1.2  Semantic Compliance Categories                 13
               3.1.3  Originator fields                              13
               3.1.4  Recipient fields                               14
               3.1.5  Date fields                                    15
               3.1.6  Cross-reference fields                         16
               3.1.7  Message-handling fields                        16
               3.1.8  Message-content fields                         17
               3.1.9  Extensions                                     18

                                      i                                 



          3.2  Message Processing Functions                          18
               3.2.1  Message creation and posting                   19
               3.2.2  Message reissuing and forwarding               20
                    3.2.2.1  Redistribution                          22
                    3.2.2.2  Assignment                              22
               3.2.3  Reply generation                               23
               3.2.4  Cross referencing                              24
                    3.2.4.1  Unique identifiers                      24
                    3.2.4.2  Serial numbering                        24
               3.2.5  Life span functions                            25
               3.2.6  Requests for recipient processing              25
                    3.2.6.1  Message circulation                     26
          3.3  Multiple Occurrences and Ordering of Fields           26

      4.  SYNTAX                                                     28

          4.1  Introduction                                          28
               4.1.1  Message structure                              28
               4.1.2  Data elements                                  29
                    4.1.2.1  Primitive data elements                 30
                    4.1.2.2  Constructor data elements               30
               4.1.3  Properties                                     30
                    4.1.3.1  Printing-names                          30
                    4.1.3.2  Comments                                31
               4.1.4  Data compression and encryption                31
               4.1.5  Data sharing                                   31
          4.2  Overview of Syntax Encoding                           32
               4.2.1  Identifier Octets                              32
               4.2.2  Length code and Qualifier components           33
                    4.2.2.1  Length Codes                            35
                    4.2.2.2  Qualifier                               36
               4.2.3  Property-List                                  38
               4.2.4  Data Element Contents                          38
          4.3  Data Element Syntax                                   39
               4.3.1  Data elements                                  39
                    4.3.1.1  Primitives                              42
                    4.3.1.2  Constructors                            44
               4.3.2  Using data elements within message fields      48
               4.3.3  Properties and associated elements             49
               4.3.4  Encryption identifiers                         49