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<p>Recently  developed  high  speed  networks  are  capable  of  transmitting  data  at  rates  of  100  Mbps  or  more.  One  such  network  protocol  is  Fiber  Distributed  Data  Interface  (FOOl).  This  network  has  a  physical.  transmissiop  rate  of  100  Mbps.  Analytical  and  simulation  studies  have  shown  that  t:le  FOOl  protocol  should  provide  actual  throughput  of  HO%  to  95%  of  this  physical  rate.  Can  the  end  user  expect  to  see  this  kind  of  performance?  If  not,  then  what  kind  of  throughput  can  actually  be  expected  and  where  are  the  bottle  necks? To  answer  these  and  other  related  questions,  two  areas  were  studied:  First,  a  perfomance parison  between  a  40MHz  SPARCstation  10  workstation  and  a  50MHz  SPARCstation 10 workstation was  conducted  using  the  Neal  Nelson  commercial  benchmark  tool.  Next,  a  well-known  network  measurement  tool,  ttcp,  was  used  to  obtain  data  transfer  rates  while  varying  several  tunable  operating  system  and  network  parcll11eters.  The  parameters  varied  were:  Target  Token  Rotation  Time,  TCP/IP  window  size,  NFS  asynchronous  threads,  Logical  Link  buffer  siu  and  Maximum  Transfer  Unit  size.  The  results  from  the  commercial  benchmar~  analyis  were  used  to  determine  if  there  are  any  differences  which  can  affect  transfer  rates  between  the  two  workstations.  The  results  from  the  conunercial  benchmark  tool  clearly  showed  that  the  newer,  higher  speed  processor  is  faster.  The  network  tool  ttcp  showed  that  the  TCP/IP  window  size  had  the  largest  impact  on  throughput  performance.  Throughput  more  than  doubles  from  a  window  size  of  4k  to  a  window  size  of  20k.  This  is  followed  by  having  more  than  one workstation  transmitting  data  simultaneously.  Having  two  workstations  transmitting  nearly  halves  throughput  This  is  followed  by  having  a  faster  processor.  A  measurement  of  flle transfers  using  rep  system  calls  showed  that  the  largest  impact  on  file  transfer  speed  is  the overhead  of  receiving  the  transferred  file.
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<br>Subjects: NA</div>
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Schivley, Mark A.</div>
Internet Archive identifier