Date: Fri, 23 May 1997 15:23:41 +0100 (BST) From: Mr M P Searle <csubl@csv.warwick.ac.uk> To: neswold@fnal.gov Cc: simat@enta.net, freebsd-questions@freebsd.org Subject: Re: PPP Dialin, burst traffic Message-ID: <14513.199705231423@bourbon.csv.warwick.ac.uk> In-Reply-To: <Pine.GSO.3.95.970521091043.19977B-100000@aduxb.fnal.gov> from Richard Neswold at "May 21, 97 09:22:24 am"
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> On Wed, 21 May 1997, Simon N Atkin wrote: > > > Hi, setup my freebsd bsd box at the weekend for dialin with PPP running > > across it, > > > > It's much faster than using a router (obviously) But when downloading a > > file from the server that the modem is connected to I only get burst > > pulses of traffic. > > > > [snip] > > > > Just in case anyone doesn't understand burst pulse traffic, then it is > > that the modem RX light doesn't stay on all the time while transfering , > > i.e loss of bandwidth. > > I've used both SLIP and PPP under FreeBSD, OS/2, Linux, and Win95. I've > *never* seen a continuous stream of data under any of these implementations. > I always assumed it was due to TCP/IP handshaking and how loaded each > machine is. If you're downloading off the Internet, you also have to worry > about every machine that forwards your packets and the handshaking needed > every step of the way. > > If I need to download a large file as quickly as possible, I'll dial in to > my shell acount using 'minicom' and grab the file with ZMODEM. That's when I > see continuous data being sent. > I've seen something very close to a continuous stream using SLIP on an Acorn. (I'm using the same way as you - looking at the RX light.) The transfer rate is maybe a little less than with Zmodem, but it's a compressing modem so it's hard to tell. Of course, the overhead of both TCP/IP and Zmodem don't show up on this. (although you can get some idea by looking at the transmit light.) Maybe it's your ISP? (I'm on Demon Internet.) I do see the occasional short flicker off, presumably a noisy line, and sometimes it will stop for maybe 30 seconds (a bug in the SLIP software I think, as I didn't get it before I 'upgraded'.), but I've seen maybe 30 seconds of continuous transfer. It doesn't seem to make much difference where the transfer is from - it's the modem (14k4) that's the bottleneck in most cases, although I do sometimes get pulsed traffic that sounds like what you have - usually when the site is a long way away and/or it's a slow time.
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