rfc1007.txt

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Network Working Group                                         Wayne McCoy
Request for Comments: 1007                                       June 1987



                         MILITARY SUPPLEMENT

                               TO THE

                       ISO TRANSPORT PROTOCOL


Status of this Memo

   This RFC is being distributed to members of the Internet community
   in order to solicit comments on the Draft Military Supplement.
   While this document may not be directly relevant to the research
   problems of the Internet, it may  be of some interest to a number
   of researchers and implementors. Distribution of this memor is
   unlimited.


1. SCOPE

1.1   Purpose.

   This document supplements the Transport Service and Protocol of the
   International Standards Organization (ISO), IS 8072 and IS 8073,
   respectively, and their formal descriptions by providing conventions,
   option selections and parameter values to be used when the protocol
   is operated within the scope of the applicability statement in
   Paragraph 1.3 below.  Paragraph 1.4, below, describes the ISO
   standards.  Full implementation detail is not provided in this
   document, but reference is made to a separate document, entitled
   "Implementation Guide for the ISO Transport Protocol", in which
   guidance for implementation is given.

1.2  Organization.

   Five sections comprise this supplement.  In Section 1, the role and
   purpose of the Transport Protocol are stated and the international
   standards upon which the protocol is based are described.  These
   documents, as well as others supporting  the international standards
   and this supplement are listed in  Section 2.  Other definitions not
   already included in the international standards and supporting
   documents are given in Section 3.  The international standards cover
   a very wide variety of network environments and situations.  There
   is, thus, a collection of options and parameters provided by the
   standards which must be determined for specific uses.  Section 4
   states the options and parameters relevant to those implementations
   to which this supplement applies, and defines usage conventions.



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   Conventions for addressing and Transport connection reference
   number usage and recovery of the Transport connection from peer
   deactivation are covered in Section 5.

1.3   Application.

   The use of the Transport Protocol Class 4 and the Protocol for
   Providing the Connectionless-Mode Network Service (IS 8473) is
   mandatory foruse in all DOD packet-switched data networks where
   there is a potential for host-to-host connectivity across network
   or subnetwork boundaries.  The term "network" as used here shall
   include Local Area Networks but not integrated weapons systems.
   The use of the Transport Protocol Class 4 and IS 8473 is
   strongly encouraged, particularly  where a need for equipment
   interchangeability or survivability is perceived. Use of the
   Transport Protocol Class 4 and IS 8473 in weapons systems, where
   such usage does not diminish required performance, is also
   encouraged.

1.4   International Standards Organization Transport Protocol.

   The international standard upon which this supplement is based is
   described in four documents:

       a. IS 8072, the Transport Service Definition, which defines the
          service that Transport provides to a user, described in
          English text;

       b. WG4 N53, the Formal Description of the Transport Service, in
          which the Transport Service is described using a formal
          description language;

       c. IS 8073, the Transport Protocol, in which the protocol is
          specified in English text; and

       d. N123, the formal description of the Transport Protocol, in
          which the specification IS 8073 is written in a formal
          description language.

   The ISO protocol has five classes of service, named Class 0 through
   Class 4.  Only Classes 4 and 2 will apply to this supplement.  The
   formal description language, Estelle, DP 9074, provides for protocol
   descriptions in terms of communicating finite state automata. It
   contains a subset language which corresponds to the international
   standard Pascal.  The Class 4 protocol operation when supported by a
   connectionless network service is described in an addendum to IS
   8073, N3339(rev).







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RFC 1007                                                       June 1987


2.  REFERENCED DOCUMENTS

2.1  Issues of Documents.

   The following documents of the issue in effect on date of invitation
   for bids or request for proposal form a part of this supplement to
   the extent specified herein.

                 FED-STD-1037  - Federal Standard - 1037,
                   Glossary of Telecommunication Terms.

            Implementation Guide for the ISO Transport Protocol

2.2  Other Publications.

   The following documents form part of this standard to the extent
   specified herin.  Unless otherwise indicated, the issue in effect on
   the date of invitation for bids or request for proposal shall apply.

   IS 8072 - Information Processing Systems -
        Open Systems Interconnection - Transport Service Definition.
        Available from: ANSI ISO TC97/SC6 Secretariat 1430 Broadway
        New York, NY 10018 [phone]

   IS 8073 - Information Processing Systems -
        Open Systems Interconnection - Transport  Protocol
        Specification. Available from ANSI (SC6 Secretariat).

   N3339(rev) - Draft Proposed Addendum to IS 8073
        to Enable Class 4 Operation Over Connectionless Mode Network
        Service as Defined in ISO/ISO 8348/AD1.  Available from ANSI
        (SC6 Secretariat).

   DP 9074 - Estelle - A Formal Description
        Technique Based on an Extended State Transition Model.
        Available from ANSI (SC21 Secretariat), address as for SC6,
        above.

   WG4 N53 - Information Processing Systems -
        Open Systems Interconnection - Formal Description of IS 8072
        in Estelle. (Working draft, ISO TC 97/SC 6/WG 4)

   N123 - Information Processing Systems -
        Open Systems Interconnection - Formal Description of IS 8073
        in Estelle. (Working draft, ISO TC 97/SC 6)

   IS 8473 - Information Processing Systems -
        Data Communications - Protocol for Providing the
        Connectionless-mode Network Service. Available from ANSI
        (SC6 Secretariat).




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RFC 1007                                                       June 1987


3. DEFINITIONS

3.1   Definition of terms.

   The definition of terms used in this standard shall comply with
   FED-STD-1037, ISO IS 8072, IS 8073 and IS 8473.  Other terms and
   definitions unique to N3756, WG4 N53 and N3339(rev) appear in
   those documents.

3.2   Abbreviations and acronyms.

   The following abbreviations and acronyms are used in this
   supplement:

     a.  ISO.  The International Standards Organization;

     b.  OSI.  Open Systems Interconnection;

     c.  TS.  Transport service;

     d.  TSAP.  Transport service access point;

     e.  NSAP.  Network service access point;

     f.  TPDU.  Transport protocol data unit;

     g.  CR.  Connect request;

     h.  CC.  Connect confirm;

     i.  DR.  Disconnect request;

     j.  ER.  Error;

     k.  AK.  Acknowledgement;

     l.  IP.  Internetwork protocol;

     m.  LAN.  Local area network.

     n.  CONS. Connection oriented network service.

     o.  CLNS. Connectionless network service.

     (Other provisions of this Section are under consideration.)









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RFC 1007                                                       June 1987


4. GENERAL REQUIREMENTS

4.1   Conformance.

   Implementations to which this supplement applies shall satisfy the
   conformance requirements (Clause 14, of IS 8073 and N3339(rev), as
   adapted for this supplement) in the following statements.

     a.  A system claiming to implement the procedures specified
         in this standard shall comply with the requirements in
         b. - d., below.

     b.  The system shall implement:

         b.1  Class 2 or Class 0 or both, if operated over a connection
              oriented network service; or

         b.2  Class 4 if operated over a connectionless network service.

     c.  If the system implements Class 4, it shall also implement
         Class 2, if it is operated over a connection oriented network
         service.  Class 2 shall not be implemented if operation is
         exclusively over a connectionless network service.

     d.  For each class which the system claims to implement, the
         system shall be capable of:
         d.1  initiating CR TPDUs or responding to CR TPDUs with TPDUs
              or both;

         d.2  responding to any other TPDU and operating network
              service in accordance with procedures for the class;

         d.3  operating all the procedures for the class listed as
              mandatory in the Provisions of Options table below;

         d.4  operating those procedures for the class, listed as as
              optional in the Provisions of Options table, for which
              conformance is claimed; and

         d.5  handling all TPDUs of lengths up to the lesser value of:

              d.5.1  the maximum length for the class;

              d.5.2  the maximum for which conformance is claimed.

     e.  Claims of conformance shall state:

         e.1  whether or not operation over connectionless service is
              implemented;

         e.2  which class or classes of protocol are implemented, if



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RFC 1007                                                       June 1987


              operation over a connection oriented network is
              implemented;

         e.3  whether the system is capable of initiating or responding
              to CR TPDUs or both;

         e.4  which of the procedures listed in the Provisions of
              Options table are implemented;

         e.5  the maximum size of TPDU implemented; the value shall be
              chosen from the following list and all values in the list
              which are less than this maximum shall be implemented:

              128, 256, 512, 1024, 2048, 4096, or 8192 octets.

   Provision of options (adapted from IS 8073, Table 9)
    __________________________________________________________________
   |        PROCEDURE         |     CLASS 2        |     CLASS 4     |
   |__________________________|____________________|_________________|
   |                          |                    |                 |
   |TPDU with checksum        |not applicable      |mandatory        |
   |TPDU without checksum     |mandatory           |optional         |
   |__________________________|____________________|_________________|
   |                          |                    |                 |
   |Expedited data transfer   |mandatory           |mandatory        |
   |No expedited data transfer|mandatory           |mandatory        |
   |__________________________|____________________|_________________|
   |                          |                    |                 |
   |Flow control in Class 2   |mandatory           |not applicable   |
   |No flow control in Class 2|optional            |not applicable   |
   |__________________________|____________________|_________________|
   |                          |                    |                 |
   |Normal formats            |mandatory           |mandatory        |
   |Extended formats          |optional            |optional         |
   |__________________________|____________________|_________________|


   The explicit manner in which implementations, to which this
   supplement applies, shall satisfy these conformance statements is
   given in Paragraph 4.4.  The options are described in more detail in
   Paragraph 4.3.

4.2   Transport Service access parameters.