Larkin, Richard wrote: > > A much much much easier way is to use a PC, load the dummynet > image on a > floppy disk, then in about 5 minutes with the right > configuration, you have > a simulated WAN, including bandwidth and delay. > > Dummynet works on FreeBSD or, as we do, you can download the > version that > fits on a floppy and boot from it. We use it to teach our > application > developers the hard lesson that not everyone has 100Mbps link > to the > servers, most sites have 64kbps. > > Rik
That sounds very interesting and I'll look into it. I'm still very interested to learn how to do what I originally set out to do, but I fear the discussion could get a little too OT for some folks' taste. I should probably go find a good MS list to bother. I will say that in the last half hour, I was able to effect a small change in the upward direction of the window size (less than a full max segment size) using the TcpWindowSize key but am still coming up with nothing in the downward direction. For what it's worth, the small upward change resulted in a non-integer multiple of the max segment size, whereas before, the window was always exactly an integer multiple of the MSS. The window is now typically reporting at exactly 0xffff (65535). It was typically at 64240 previously, which happened to be the MSS (1460) * 44. This after I changed the above referenced key to 0x1f5e0 (128480). So there seems to be a valid range between 64240 & 65535. I'm obviously doing something wrong or there is a W2k Pro bug. Thanks again for the info on dummynet. I'd never heard of it. Hey, I'm surprised no one has taken the opportunity to convert me to Unix/Linux!? I'm sure this is much easier in that world. It's on my list of technologies to master. Sigh... > > -----Original Message----- > From: s vermill [mailto:[EMAIL PROTECTED]] > Sent: Wednesday, 18 December 2002 6:40 AM > To: [EMAIL PROTECTED] > Subject: Re: Perhaps O/T: Window TCP Rcv Window [7:59400] > > > Marc Thach Xuan Ky wrote: > > > > Are you trying to make the window smaller? > > rgds > > Marc > > Yes. I was hoping to set up a demonstration on the impact of > high > bandwidth*delay product networks without actually having a high > bandwidth*delay product network. By artifically enforcing a > small rcv > window, I should get about the same result. > > Thanks Marc, > > Scott > > > > > s vermill wrote: > > > > > > On a W2k machine, I've tried several different > > recommendations for adjusting > > > the TCP receive window size. None of them, including those > > directly from > > > Microsoft, seem to have any impact. I'm capturing my own > > traffic and my > > > advertised window is always in the 64k range. > > > > > > I've tried editing the \tcpip\parameters to include > > 'TcpWindowSize' and > > > 'GlobalMaxTcpWindowSize' - neither of which had any effect. > > I've tried > > > editing \VxD\MSTCP to include 'DefaultRcvWindow' - also no > > effect. > > > > > > Anyone know how to manipulate the rcv window that my machine > > will > > > advertise. For that matter, what about the other MS OSes? > > XP? Win98? > > > > > > Thanks all, > > > > > > Scott > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=59417&t=59400 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
