GENWiki

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

Wessler [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]