Movatterモバイル変換

Network Working Group                                         B. WesslerRequest for Comments: 557                         Telenet CommunicationsNIC: 18457                                                30 August 1973References:RFC 392, 415                REVELATIONS IN NETWORK HOST MEASUREMENTS   The purpose ofRFC 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'sRFC 415 measuring TENEX).   Since the Publication ofRFC 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 visWessler                                                         [Page 1]

RFC 557         REVELATIONS IN NETWORK HOST MEASUREMENTS     August 1973   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.         [ This RFC was put into machine readable form for entry ]             [ into the online RFC archives by Lorrie Shiota ]Wessler                                                         [Page 2]