Date: Tue, 23 Feb 1999 14:21:49 -0500 (EST) From: "John S. Dyson" <dyson@iquest.net> To: imp@village.org (Warner Losh) Cc: vincef@penmax.com, dennis@etinc.com, hackers@FreeBSD.ORG Subject: Re: cdrom.com bandwidth limits Message-ID: <199902231921.OAA03755@y.dyson.net> In-Reply-To: <199902222128.OAA15308@harmony.village.org> from Warner Losh at "Feb 22, 99 02:28:11 pm"
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Warner Losh said: > > I'm usually bandwidth limited by the T1 that is my connection to the > outside world, so I usually see 100-140kBps. > > This is about 1000-1400 kbps, which is near the max 1500 kbps a T1 > supports. > approx: 1500 / (8bits + epsilon) or 187Kbytes/sec. It is not likely to get that much due to protocol overheads, but I have seen >160KBytes/sec on a good T1. Don't T1's do bit stealing for signalling (I forget?) So, the "epsilon" above should account for that. It all depends on type of T1 (T1 is a hardware transport, that mostly implies some of the upper levels also, but you can have a T1 type transport for PRI ISDN also.) Most people do mean the standard T1 when they say T1 though. Framing (or byte) overheads suck away bandwdith, and the T1 is pretty good in that area. Some people don't realize that the T1 is bidirectional also (most people who work with them do realize this though.) This is a bit of a bonus, so you can sustain 150Kbytes/sec inward and outward. (I just realized that I am also sending this to dennis@etinc.com :-), correct me if I am wrong :-)). -- John | Never try to teach a pig to sing, dyson@iquest.net | it makes one look stupid jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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