The Design Philosophy of the DARPA Internet Protocols

From: Masaharu Kobashi (mkbsh@cs.washington.edu)
Date: Sun Oct 03 2004 - 12:50:46 PDT

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    1. Main result of the paper

       It describes the Internet protocols and architecture in the historical
       perspective explaining the motivations and evolution which led them to
       their current state. It also sheds light on desirable future
       improvements on the Internet design.

    2. Strengths in this paper

       First, unlike most other literature, it provides a historical
       perspective and reasoning on why and how they have reached their
       current state.
       Understanding the historical development and process of evolution
       gives us valuable insight for analyzing problems and forecasting future
       needs.

       Second, it provides very practical view of various problems such as
       pointing out problems in the network design aids (page 111), most of
       which, the author claims, lack the guidance on performance issues which
       is vital in real implementation. Throughout the paper the same spirit
       of practicality is alive.

       Third, it gives us clear and detailed information on the motivation
       behind the design of the Internet which is rarely available in most
       other literature. For example, it explains in detail why TCP's flow
       control is byte number based rather than packet number based.

       Forth, it clearly shows the order of priority among the goals of the
       Internet design. This information is rarely available and it alone can
       explain some decisions which involve trade off relations among the
       goals.

    3. Limitations/shortcomings and suggested improvements

       Overall it is well written and very informative. But there is still
       room for improvement.
       
       First, there is no discussion on the impact of the extremely fast
       technology development of hardware and the reduction of hardware costs.
       These factors can have substantial impact on the evolution of the
       Internet in terms of design and demand/availability of types of
       services.

       Second, there is no discussion on the impact of changing pattern of
       services and changing types of user groups on the performance of
       the Internet. This discussion is important because it is related to
       the Internet's core capability to accommodate wide variety of services
       and networks and also because there has been constant changes in them.

       Third, it would have been interesting if the author described what
       would have been the design of the Internet if it were created from the
       beginning for civil/commercial use instead of military objectives.
       At least he should have pointed out which goals would have been removed
       or added or modified if the Internet was designed for civil/commercial
       use.

    4. Relevance today and future

       The paper has great relevance to both today's and future work on the
       Internet since historical review can help us avoid future mistakes
       and forecast potential dangers and opportunities.
       The relevance in this respect is clear as the author explicitly states
       what are the necessary improvements on the Internet. He claims they are
       in the areas of resource management, accounting, and operations of
       regions with separate administrations.


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