From owner-freebsd-chat Wed Apr 26 1:50:21 2000 Delivered-To: freebsd-chat@freebsd.org Received: from PacHell.TelcoSucks.org (pachell.telcosucks.org [207.90.181.5]) by hub.freebsd.org (Postfix) with ESMTP id 0D70437B8F9 for ; Wed, 26 Apr 2000 01:50:18 -0700 (PDT) (envelope-from ulf@PacHell.TelcoSucks.org) Received: (from ulf@localhost) by PacHell.TelcoSucks.org (8.9.3/8.9.1) id BAA53824; Wed, 26 Apr 2000 01:48:54 -0700 (PDT) (envelope-from ulf) Date: Wed, 26 Apr 2000 01:48:54 -0700 From: Ulf Zimmermann To: Joe Greco Cc: chat@FreeBSD.ORG, ryan@sasknow.com Subject: Re: Max. T1 throughput? Message-ID: <20000426014854.I39536@PacHell.TelcoSucks.org> Reply-To: ulf@Alameda.net References: <200004300920.EAA55001@aurora.sol.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <200004300920.EAA55001@aurora.sol.net>; from jgreco@ns.sol.net on Sun, Apr 30, 2000 at 04:20:30AM -0500 Organization: Alameda Networks, Inc. X-Operating-System: FreeBSD 3.4-STABLE Sender: owner-freebsd-chat@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Sun, Apr 30, 2000 at 04:20:30AM -0500, Joe Greco wrote: > > There seems to be some confusion around our region on what the maximum > > throughput of a T1 is. (Actually, we are on a 1.544Mbps leased SDSL line > > from a local ISP. The package was sold to us as a burstable T1). > > > > My preliminary tests seem to show a segregation between up and > > down... Each maxing out at about 96KB/sec when the other is practically > > idle. Not the near-198KB/sec that I think I should be getting. > > > > Is SDSL the key, here? Perhaps I took "Synchronous" in the wrong > > way. Does "Synchronous" imply UP = DOWN = 1.54Mbps / 2? > > A T1 is 1.544 megabits per second. Dividing by 8, you get 193 kilobytes > per second, an often-quoted number as being T1 capacity. > > By the time you get through with all sorts of odd issues, though, I find > that a T1's peak capacity is about 160K/s. My experience is about 185KB/sec on a point to point T1, using ftp to transfer files. That means you have some overhead for IP, TCP and FTP protocol. > > SDSL may imply that you are being sold a technology whose peak capacity is > the aforementioned T1 data speed. However, many DSL technologies adapt to > line conditions and distance by providing less overall throughput. It is > possible that your line is not capable of (much) more than you're getting. > A T1 would be, however, since a T1 line is engineered with appropriate > electronics (such as repeaters) to make the circuit work. A T1 cannot > vary in speed, since it must be able to bear multiplexed phone circuits. > It may experience errors, however. > > -- > ... Joe > > ------------------------------------------------------------------------------- > Joe Greco - Systems Administrator jgreco@ns.sol.net > Solaria Public Access UNIX - Milwaukee, WI 414/342-4847 > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-chat" in the body of the message -- Regards, Ulf. --------------------------------------------------------------------- Ulf Zimmermann, 1525 Pacific Ave., Alameda, CA-94501, #: 510-769-2936 Alameda Networks, Inc. | http://www.Alameda.net | Fax#: 510-521-5073 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message