Date: Sun, 21 Jun 1998 12:17:30 +0000 (GMT) From: Andrew Kenneth Milton <akm@zeus.theinternet.com.au> To: opsys@mail.webspan.net (Open Systems Networking) Cc: spork@super-g.com, joelh@gnu.org, root@bmccane.maxbaud.net, hackers@FreeBSD.ORG Subject: Re: TweakDUN Message-ID: <199806211217.MAA24261@zeus.theinternet.com.au> In-Reply-To: <Pine.BSF.3.95.980620013654.20127D-100000@orion.webspan.net> from Open Systems Networking at "Jun 20, 98 01:51:24 am"
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+----[ Open Systems Networking ]--------------------------------------------- | On Fri, 19 Jun 1998, spork wrote: | | > I can't think of anywhere this is true. I'll use our dialup pools as an | > example: | > | > modem-> dialup PPP 1500 -> term server -> ethernet 1500 -> router -> T1(s) | > HDLC 1500 -> core router -> fast ethernet 1500 -> upstream's border | > router -> FDDI 40?? -> upstream core router -> ATM/SONET/whatever ? | > | > Generally, one avoids small MTUs on big links, I beleive. ATM's small | > cell size makes *every* packet get fragmented at layer 2, but I'm not sure | > that's even relevant. | > | > Anyone else? I've never heard of the oft quoted "Internet standard MTU of | > 576"... | | Me either, and theres a reason. Its braind dead to do so. Way back when, when 9600 was fast and telephone lines were crap(pier), we used to set the MRU to 296; 256 + 40 bytes PPP header. Interactivity was one reason, the other was to avoid retransmissions of massive packets when doing anything traffic intensive. It did turn out to be much faster at the time. I'm guessing the 296 has migrated to 576 with the new modem speeds although I can't really work that derivation out (not that I've really exhausted any brain power on it). -- Totally Holistic Enterprises Internet| P:+61 7 3870 0066 | Andrew The Internet (Aust) Pty Ltd | F:+61 7 3870 4477 | Milton ACN: 082 081 472 | M:+61 416 022 411 |72 Col .Sig PO Box 403 Booval QLD Australia 4304 |akm@theinternet.com.au|Specialist To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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