Date: Tue, 3 Dec 1996 16:12:15 -0800 (PST) From: Wes Santee <wes@bogon.net> To: af@biomath.jussieu.fr (Alain FAUCONNET) Cc: msmith@revolution.3-cities.com, wes@bogon.net, questions@FreeBSD.ORG Subject: Re: Why such poor PPP throughput? Message-ID: <199612040012.QAA23544@bogon.net> In-Reply-To: <199612032326.AA08027@iaka.biomath.jussieu.fr> from Alain FAUCONNET at "Dec 4, 96 00:26:47 am"
next in thread | previous in thread | raw e-mail | index | archive | help
>From the desk of Alain FAUCONNET comes: > > I would carefully check input flow control i.e. can your computer > throttle data coming from the modem ? (check modem settings for > CTS/RTS flow control, check tty setting and PPP options for hardware > flow control too). I've got CTS/RTS flow control turned on on both the modem, and the ppp settings (and I've got XON/XOFF specifically turned off). I do have error correction enabled on the modem also. One interesting factoid I forgot to mention is that while tcpdump-ing an ftp transfer to my machine from my ISP (again, 1 hop), I noticed that the receive window buffer was pegged at 16KB on the socket. So, data wasn't even coming in fast enough for IP to squelch it. Still, like you mention, while this may account for low receive throughput, it doesn't explain how bad packets are getting through. Nor does it explain why the send throughput is so much better and error-free (you'd think line noise would be an equal opportunity packet zapper). Cheers, -Wes -- ( -Wes Santee <wes@bogon.net> Homepageless - and proud ) ( PGP: email w/Subject: "Send PGP Key" Powered by FreeBSD )
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199612040012.QAA23544>