RFC 415 (rfc415) - Page 1 of 2

Tenex bandwidth

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Network Working Group                                          H. Murray
Request for Comments: 415                    Stanford Research Institute
NIC: 392                                                29 November 1972


                            TENEX BANDWIDTH

   NIC 11584 (RFC 392) BY G. HICKS AND B. WESSLER AT UTAH RECENTLY
   DISCUSSED THE COST OF USING THE NETWORK.

   I WOULD LIKE TO TAKE THESE SAME TYPES OF NUMBERS AND LOOK AT THEM
   FROM ANOTHER POINT OF VIEW.  WITHOUT CALCULATING COSTS, LET US
   CONSIDER ULTIMATE PERFORMANCE OF THE HOSTS.  I WROTE A SIMPLE TENEX
   PROGRAM THAT SENT ITSELF STRINGS OVER THE NET.  IT USED BIN/BOUT AND
   THE BUFFERED SEND MODE.   IT COUNTED THINGS, BUT DID NOT PROCESS THE
   STRING.  WITH SAMPLES OF A MILLION BITS, THE FOLLOWING RESULTS WERE
   OBTAINED.

   BYTES/SIZE      REAL BAUD       CPU BAUD      CPU NEEDED

     50/36          48.8K           291K          16%
    100/36          46.5K           309K          15%
    200/36          52.7K           322K          16%
    400/36          59.3K           267K          22%
    800/36          61.1K           279K          21%

     50/8           22.0K           70K           31%
    100/8           26.7K           76K           35%
    200/8           29.0K           79K           36%
    400/8           30.0K           81K           37%
    800/8           31.9K           78K           40%
   1600/8           38.1K           64K           59%
   3200/8           41.8K           59K           70%

   THE FOLLOWING WERE OBTAINED BY USING SIN/SOUT WITHOUT THE BUFFERED
   MODE.

   BYTES/SIZE      REAL BAUD       CPU BAUD      CPU NEEDED
     50/36          36K             95K           38%
    100/36          44K             95K           45%
    200/36          49K             92K           53%
    400/36          54K             90K           60%

     50/8           12K             22K           57%
    100/8           16K             21K           75%
    200/8           18K             20K           92%
    400/8           20K             20K           99%




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