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The RWIN calculation requires a latency value for a large packet, pinged some distance and averaged.

To find this value, open a command prompt and type: ping -t -l 1472
(where is any URL you like as long as it's fairly distant from you.)

Note that the -l is a lower case L, not an I. Also note that if you use PPPoE, use 1464 or lower, not 1472. In other words, use a number that is 28 less than your reported MTU.

If you are on the east coast of the US, for instance, you'd want to pick a western URL. Colleges seem to work well since their websites are generally located somewhere on campus.

If the pings time out, you've chosen a URL that is blocking ping. Press "Ctrl" and "C" together and the request will stop. Choose a different URL and try again. Once you find a site that responds, let it run for two or three minutes and then press "Ctrl" and "C" together.

A summary will be displayed showing an average result time in milliseconds. Multiply this value by 1.5 and use the result in the RWIN calculation formula.

Feedback received on this FAQ entry:
  • Ctrl + C does not produce expected results. Request continues with no summary

    2009-04-27 22:33:23 (budscyn See Profile)

  • I tried over 5 different urls. All timed out, I gave up.

    2008-10-12 19:39:38 (dgriff23 See Profile)

Expand got feedback?

by garp123 See Profile edited by JMGullett See Profile
last modified: 2007-02-27 09:54:48