rfc942.txt

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National Research Council                                      [Page vi]

RFC 942                                                    February 1985
Report Transport on Protocols

                                CONTENTS

PREFACE ............................................................  ix

EXECUTIVE SUMMARY ..................................................  xi

I     Introduction ..................................................  1

II    Review of NBS and DOD Objectives ..............................  3

III   Comparison of DOD and ISO Protocols ..........................  13

IV    Status of DOD and ISO Protocol
      Implementations and Specifications ..........................   25

V     Markets ......................................................  31

VI    Development of Standard Commercial versus
      Special Commercial Products ..................................  39

VII   Responsiveness of International Standards
      Process to Change ............................................  43

VIII  Options for DOD and NBS ......................................  45

IX    Cost Comparison of Options ..................................   47

X     Evaluation of Options ........................................  53

XI    Recommendations ..............................................  61
























National Research Council                                     [Page vii]

RFC 942                                                    February 1985
Report Transport on Protocols

                                      

     



















































National Research Council                                    [Page viii]

RFC 942                                                    February 1985
Report Transport on Protocols

                                PREFACE

This is the final report of the National Research Council Committee on
Computer-Computer Communication Protocols.  The committee was
established in May l983 at the request of the Department of Defense
(DOD) and the National Bureau of Standards (NBS), Department of
Commerce, to develop recommendations and guidelines for resolving
differences between the two agencies on a data communications transport
protocol standard.

Computer-based information and transaction-processing systems are basic
tools in modern industry and government.  Over the past several years
there has been a growing demand to transfer and exchange digitized data
in these systems quickly and accurately.  This demand for data transfer
and exchange has been both among the terminals and computers within an
organization and among those in different organizations.

Rapid electronic transport of digitized data requires electronic
communication links that tie the elements together.  These links are
established, organized, and maintained by means of a layered series of
procedures performing the many functions inherent in the communications
process.  The successful movement of digitized data depends upon the
participants using identical or compatible procedures, or protocols.

The DOD and NBS have each developed and promulgated a transport protocol
as standard.  The two protocols, however, are dissimilar and
incompatible.  The committee was called to resolve the differences
between these protocols.

The committee held its first meeting in August l983 at the National
Research Council in Washington, D.C.  Following this two-day meeting the
committee held five more two-day meetings, a three-day meeting, and a
one-week workshop.

The committee was briefed by personnel from both agencies.  In addition,
the committee heard from Jon Postel, University of Southern California's
Information Sciences Institute; Dave Oran, Digital Equipment
Corporation; Vinton Cerf, MCI; David Wood, The Mitre Corporation; Clair
Miller, Honeywell, and Robert Follett, IBM, representing the Computer
and Business Equipment Manufacturer's Association; and John Newman,
Ultimate Corporation.  In most cases the briefings were followed by
discussion.

The committee wishes to thank  Philip Selvaggi of the Department of
Defense and Robert Blanc of the NBS, Institute of Computer Sciences and









National Research Council                                      [Page ix]

RFC 942                                                    February 1985
Report Transport on Protocols

Technology, for their cooperation as their agency's liaison
representatives to the committee.  The committee appreciates the
contributions and support of Richard B. Marsten, Executive Director of
the Board on Telecommunications -- Computer Applications (BOTCAP), and
Jerome D. Rosenberg, BOTCAP Senior Staff Officer and the committee Study
Director.  We also wish to thank Lois A. Leak for her expert
administrative and secretarial support.















































National Research Council                                       [Page x]

RFC 942                                                    February 1985
Report Transport on Protocols

                           EXECUTIVE SUMMARY

Computer communication networks have become a very important part of
military and commercial operations.  Indeed, the nation is becoming
dependent upon their efficiency and reliability, and the recent
proliferation of networks and their widespread use have emphasized the
importance of developing uniform conventions, or protocols, for
communication between computer systems.  The Department of Defense (DOD)
and the National Bureau of Standards (NBS) have been actively engaged in
activities related to protocol standardization.  This report is
concerned primarily with recommendations on protocol standardization
within the Department of Defense.

Department of Defense's Transmission Protocol

 The DOD's Defense Advanced Research Projects Agency (DARPA) has been
 conducting and supporting research on computer networks for over
 fifteen years (1).  These efforts led to the development of modern
 packet-switched network design concepts.  Transmission between
 computers is generally accomplished by packet switching using strict
 protocols for the control and exchange of messages.  The Advanced
 Research Projects Agency network (ARPANET), implemented in the early
 1970s, provided a testing ground for research on communications
 protocols.  In 1978, after four years of development, the DOD
 promulgated versions of its Transmission Control Protocol (TCP) and an
 Internet Protocol (IP) and mandated their use as standards within the
 DOD.  TCP is now widely used and accepted.  These protocols meet the
 unique operational and functional requirements of the DOD, and any
 changes in the protocols are viewed with some trepidation by members of
 the department.  DOD representatives have stated that standardizing TCP
 greatly increased the momentum within the DOD toward establishing
 interoperability between networks within the DOD.

International Standards Organization's Transport Protocol

 The NBS Institute for Computer Sciences and Technology (ICST), in
 cooperation with the DOD, many industrial firms, and the International
 Standards Organization (ISO), has developed a new international
 standard

 









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(1)  The Advanced Research Projects Agency (ARPA) was reorganized and
became the Defense Advanced Research Projects Agency (DARPA) in 1973.

National Research Council                                      [Page xi]

RFC 942                                                    February 1985
Report Transport on Protocols

 Transport Protocol (TP-4) and a new Internetwork Protocol (2).  These
 protocols will soon be available as commercial products.  Although in
 part derived from TCP, the new protocols are not compatible with
 TCP (3).  The U.S. standards organizations are supporting TP-4 in
 international operations, and the Department of Commerce is proposing
 TP-4 as a Federal Information Processing Standard (FIPS) for use by all
 federal agencies.

DOD OPERATIONAL AND TECHNICAL NEEDS

 The DOD has unique needs that could be affected by the Transport and
 Internet Protocol layers.  Although all data networks must have some of
 these capabilities, the DOD's needs for operational readiness,
 mobilization, and war-fighting capabilities are extreme.  These needs
 include the following:

  Survivability--Some networks must function, albeit at reduced
  performance, after many nodes and links have been destroyed.

  Security--Traffic patterns and data must be selectively protected
  through encryption, access control, auditing, and routing.

  Precedence--Systems should adjust the quality of service on the basis
  of priority of use; this includes a capability to preempt services in
  cases of very high priority.

  Robustness--The system must not fail or suffer much loss of capability
  because of unpredicted situations, unexpected loads, or misuse.  An
  international crisis is the strongest test of robustness, since the
  system must operate immediately and with virtually full performance
  when an international situation flares up unexpectedly.

  Availability--Elements of the system needed for operational readiness
  or fighting must be continuously available.

  Interoperability--Different elements of the Department must be able to
  "talk" to one another, often in unpredicted ways between parties that
  had not planned to interoperate.

  

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(2)  The ISO Transport Protocol and ISO Internetwork Protocol became