REVELATIONS IN NETWORK HOST MEASUREMENTS

Network Working Group                                         B. Wessler
Request for Comments: 557                         Telenet Communications
NIC: 18457                                                30 August 1973
References: RFC 392, 415


                REVELATIONS IN NETWORK HOST MEASUREMENTS

   The purpose of RFC 392 was to identify a problem we had encountered
   in using the ARPANET at Utah.  The primary thrust of the paper was
   supposed to be: "Here is a place to make the Network better" rather
   than: "Look, isn't the Network terrible."  The accepted use of 392
   seems to be the latter rather than the former.  A second purpose of
   392 was to stimulate the undertaking of measurement experiments on
   other computers and operating systems in addition to TENEX.  Very
   little in the way of measurements has been reported (other than Hal
   Murray's RFC 415 measuring TENEX).

   Since the Publication of RFC 392, BBN has done a considerable amount
   of work to improve Host-Net performance on TENEX.  They reported new
   measurement results in their April 1973 Quarterly Progress Report No.
   10.  I feel it is important to circulate those results to the RFC
   community.

   Don Allen at BBN borrowed Greg Hicks' RJS program and 1) updated it
   to take advantage of recent changes in TENEX, 2) improved the code
   near the input/output JSYs and 3) used considerably faster network
   monitor code.  The result was approximately 400% improvement from
   75-85 seconds of CPU time per megabit (~$10) to 19 seconds per
   megabit (~$2.50).  Of the 19 seconds, 13 were spent in the RJS
   program and 6 in TENEX network output.  The six seconds seem to
   relate very well to BBN FTP requirements where 8.2 cpu seconds per
   megabit were required (~$1.08) for 8 bit byte transfers.  (Going to
   32 or 36 bit bytes improves this figure by a factor of 4, resulting
   in a cost of $.33 per megabit.)

   Of the 13 seconds left in RJS no attempt was made to improve or even
   discover where the time was spent.  This extra effort was not
   expended because RJS is soon to be replaced by the RJE protocol which
   uses FTP as its transfer mechanism.

   In summary, I believe that the original RFC #392 and the recent BBN
   results show that the Network including the Host cost, is
   intrinsically effective.  If care is not taken in monitor and user
   code the system may not look very attractive.  I hope everyone now
   goes out and measures how good (or bad) they are doing vis a vis
   network transfers.  Please send me the results personally if they are
   too embarrassing to distribute via RFC.  It would be nice to hear
   from all systems.

   All the data is courtesy of Don Allen and Jerry Burchfiel at BNN.


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