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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!news.eng.convex.com!newshost.convex.com!newsgate.duke.edu!news.mathworks.com!uunet!inXS.uu.net!news.fido.net!dispatch.news.demon.net!demon!mail2news.demon.co.uk!djwhome.demon.co.uk From: David Woolley <david@djwhome.demon.co.uk> Newsgroups: demon.ip.support,demon.tech.unix,comp.unix.bsd.freebsd.misc Subject: Re: Batch FTP and Web Pages Date: Wed, 3 Jul 1996 23:18:32 GMT Organization: Demon Subscriber at Home Lines: 71 Sender: news <news@djwhome.demon.co.uk> Message-ID: <Dtzq2x.HzM@djwhome.demon.co.uk> References: <31D4AA3A.BC0@www.play-hookey.com> <31D87436.7C7F@www.play-hookey.com> <836289820snz@mynx.demon.co.uk> <836329401snz@zhochaka.demon.co.uk> X-NNTP-Posting-Host: djwhome.demon.co.uk X-Mail2News-Path: djwhome.demon.co.uk In article <836329401snz@zhochaka.demon.co.uk>, David G. Bell <dbell@zhochaka.demon.co.uk> wrote: > >Historically, the Internet has tended to use permanent connections, >which allow the use of relatively connect-time inefficient approaches. >As a for instance, look at news reading with Netscape. Bulletin Boards >have, even in the USA, developed around connect-time efficient methods, >such as off-line mail-reader programs, since minimising connect time >allows more people to _use_ a BBS. I think this highlights a popular confusion between the services carried by the Internet and the Internet itself; Demon's official line is that they only provide access to the latter (although things like their commercial web service tend to contradict this). As a result people think they must use TCP/IP to access mail and news, whereas, historically these "internet" services where carried by UUCP, and can still be obtained by UUCP. This is very much like BBS systems in operation and is the most efficient way of handling them over dial up links. File transfers would also be done over UUCP, but one would probably do this by a direct phone call to the nearest archive site (you can still do this for SCO Unix upgrades). The aim of UUCP was efficient use of dialup connections, for which high throughput is a requirement. The aim of IP is efficient use of shared permanent links; absolute throughput for an individual user was not a design requirement. This allows the backbone links to be run at very nearly 100% capacity, whereas dial up links have to be able to provide near guaranteed throughput (the reality of transatlantic phone calls is more complex than this), with a low probability of getting equipment engaged, at the peak traffic time, which means that their average utilisation is quite poor. If you want guaranteed throughput at peak times, you have to provision like telephone networks, with the associated costs.++ With the digitalisation of the telephone network another factor has been introduced. A transatlantic modem transfer would involve holding a 64k bit channel in both directions (128kbits of capacity), whereas by sharing the ISPs digital link, they can make use of that 128kbps, but have it all in one direction and not waste significant parts of it because of modem coding limiting them to 14.4kbps (at the start of the commercialisation). I quote this to illustrate an alternative view of what ISPs are doing, namely selling efficient use of long distance digital bandwidth, where the actual protocol is a technical detail. (Voice calls don't actually take 128kbps, and ISDN, which can, is surcharged; analogue modems probably do, but the volume of such calls is probably too low for PTTs to take steps to recover the cost, or handle them specially.) Unfortunately, commercial factors step in when one considers alternatives to TCP/IP. Before joining Demon, about 3 years ago, I considered a UUCP account. The reason for rejecting it was that, although cheaper, both directly and in telephone costs, I would have still needed a separate internet account if I wanted to use interactive services, and I would end up paying phone costs for thinking time, if I only used it for interactive services. So I took the position that that the additional phone time costs for mail and news would be outweighed by the saving in only having a single subscription and being able to do interactive work in parallel (If someone were to offer me a high throughput UUCP over TCP connection combined with a general purpose IP account, for a similar price to Demon, things would be different, but I don't see that happening, so I have made the commercial compromise towards IP, with NNTP and SMTP. ++ Internet ISPs have the advantage that, although their switching technology is more complex, per channel, than that used by PTTs, it is being bought at 1996 prices, whereas the PTTs are still paying back the interest on 1986 prices. -- David Woolley, London, England david@djwhome.demon.co.uk