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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!news.ysu.edu!usenet.ins.cwru.edu!pravda.aa.msen.com!spool.mu.edu!howland.reston.ans.net!newsfeed.internetmci.com!newsxfer2.itd.umich.edu!howland.erols.net!news1.erols.com!news From: Ken Bigelow <kbigelow@www.play-hookey.com> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: FTP performance with pppd Date: Wed, 07 Aug 1996 21:32:48 +0000 Organization: A poorly-installed InterNetNews site Lines: 26 Message-ID: <32090B80.2781E494@www.play-hookey.com> References: <32037C10.41C67EA6@solidsys.com> <32041EE6.8F6@www.play-hookey.com> <4u1rrj$6b2@ucthpx.uct.ac.za> NNTP-Posting-Host: kenjb05.play-hookey.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0b6 (X11; I; FreeBSD 2.1.0-RELEASE i386) S Marquard wrote: > >Try adjusting your mtu size. As long as I'm on a dialup line, I set mtu > >to 576. When/if I go to ISDN I'll up that. > > I have got throughput of about 2700bps using pppd, vs 3100bps using ijppp > (with 28.8 modems). Adjusting the mtu/mru values hasn't helped. > I'd also like to know what the difference is. > mtu/mru = maximum transmit/receive unit. This is basically the block size for your TCP/IP packets. If you don't specify something smaller, default is typically 1500 bytes per block. On a dialup link, large blocks can cause slowdowns and increased re-transmits if the line is noisy or collisions or other problems occur. A smaller block size reduces the likelihood of error, and also the size of the re-transmitted block. Of course, under 'ideal' conditions, a larger block size would be more efficient. Are your conditions guaranteed to be 'ideal?' Mine sure aren't! -- Ken Are you interested in | byte-sized education | http://www.play-hookey.com over the Internet? |