At 05:30 PM 12/18/98 -0500, Marian Stagarescu wrote:
>...The TCP throughput w/ large windows and SACK over long-fat pipes
(RTT=540 msec,
>OC-3 links) is good (72% of theoretical rate) at low BER (none or 1E-10)
>but it degrades heavily when BER is bellow
>1E-7 (only 4% of theoretical rate for BER=1E-7).
>
>
Why do you only get 72% of theoretical results for error-free links? Are
you considering SONET and ATM overhead? Theory should be approximately
134-134.5 Mbps depending on the amount of extensions used. Do you have the
advertised window set to theory or are you letting the data overrun the
available link? At LeRC over ACTS and using the Adtech for delay/error we
can get near theory minus a few percent due to the inability of the CPU and
drivers to match theory. This is when the system is perfectly tuned.
*********************************************
William D. Ivancic
NASA Lewis Research Center
21000 Brookpark Rd. MS 54-8
Cleveland, Ohio 44135
USA
Phone: 1 216 433 3494
FAX: 1 216 433 8705
Email: [email protected]
[email protected]
*********************************************
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