From owner-freebsd-isp Sun Mar 11 13:36:28 2001 Delivered-To: freebsd-isp@freebsd.org Received: from aspenworks.com (aspenworks.com [192.94.236.1]) by hub.freebsd.org (Postfix) with ESMTP id 59B5237B725 for ; Sun, 11 Mar 2001 13:36:25 -0800 (PST) (envelope-from alex@aspenworks.com) Received: from d7k (a-mcg.aspn.net [206.168.156.207]) by aspenworks.com (8.9.3/8.9.3) with SMTP id OAA00510 for ; Sun, 11 Mar 2001 14:36:20 -0700 (MST) (envelope-from alex@aspenworks.com) Message-ID: <004101c0aa73$4bdefdc0$1800a8c0@d7k> From: "Alex Huppenthal" To: Subject: ATM and traffic shaping Date: Sun, 11 Mar 2001 14:36:12 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org It turns out that traffic shaping for ATM means being able to delay each cell to a specific egress ('transmit' in english) rate. If anyone knows how to change all packet sizes to be < 48 bytes (cell header takes 5), and delay the delivery of each packet to the HARP / Fore card driver, that would be most miraculous. It would mean that it's possible to setup Classical IP over ATM on FreeBSD and adjust each PVC by associating an IP address with it, (unfortuately, just the destination IP address), and deliver ATM-shaped traffic. This would then conform to the network's expectation for offered traffic, and allow us ATM/IP network designers to use FreeBSD in the design. There's another fix, instead of FreeBSD hosting an ATM port at OC3 rates, it could host some T1 muxed thing which allows the local interface to throttle the emitted cells to some rate. This.. would suck.. since an OC3 card is $800 off the shelf and it plugs and plays nicely on the physical level with Lucent ATM switches. No $2000 DS3 CSU, and no $3000 HSSI card required. If we can't figure out a fix of the FreeBSD Harp stack or add an ioctl to the 'atm' command that would set the Fore card appropriately per PVC.. we may be forced (*choke choke* cough-sputter) to use the working Linux ATM code. I've always wondered what that kernel/environment looked like anyway.. ;-) Cheers! -Alex To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message