Messages in this thread | | | Date | Tue, 1 Sep 1998 20:13:47 -0400 (EDT) | From | "Richard B. Johnson" <> | Subject | Re: TCP Stalls. |
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On Wed, 2 Sep 1998, Alan Cox wrote:
> > If I corrupt loopback so it fails to transmit a few packets, I can > > emulate the same kind of TCP stalls that have frequented the kernel. > > I'd expect exactly what you describe. TCP cannot cope with loss above > 1 frame per pipe length without seriois performance loss. Typically thats > 5-10% loss. Above that it will back off a lot. > > Your model is then flawed because the back off doesnt induce lower error > rates through reduced congestion. You model a continuous 25% loss link > layer - and that is something that unaided is beyond the capabilities > of an IP network. > > Alan >
Okay. That's good. This might point to a serious problem with the PPP link (losing lots of packets), because that's where the bad stalls occur.
I can run serial I/O to serial I/O (regular 'C' programs in Linux) between two computers with two modems _and_ the phone line with only an occasional lost character (actually a group of 6), far less than 1/2 percent. Maybe flow-control isn't working in PPP??
Cheers, Dick Johnson ***** FILE SYSTEM WAS MODIFIED ***** Penguin : Linux version 2.1.118 on an i586 machine (66.15 BogoMips). Warning : It's hard to remain at the trailing edge of technology.
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