From owner-freebsd-isp Mon Dec 28 12:43:34 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id MAA16416 for freebsd-isp-outgoing; Mon, 28 Dec 1998 12:43:34 -0800 (PST) (envelope-from owner-freebsd-isp@FreeBSD.ORG) Received: from rachel.paradise.net.nz (rachel.paradise.net.nz [203.96.152.4]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id MAA16393 for ; Mon, 28 Dec 1998 12:43:31 -0800 (PST) (envelope-from shane.cole@staff.paradise.net.nz) Received: from shanelaptop (shaneremote.paradise.net.nz [203.96.155.1]) by rachel.paradise.net.nz (8.8.7/8.8.7) with SMTP id JAA21741; Tue, 29 Dec 1998 09:43:08 +1300 (NZDT) (envelope-from shane.cole@staff.paradise.net.nz) Message-ID: <016501be32a2$0e8a7bc0$019b60cb@paradise.net.nz> From: "Shane Cole" To: "Javier Henderson" , "Dennis" Cc: "Alan Batie" , Subject: Re: ATM WAN interface Date: Tue, 29 Dec 1998 09:38:27 +1300 MIME-Version: 1.0 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.0810.800 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.0810.800 Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org We recently changed from using a 1920kbit E1 W-DDS circuit to a 1920kbit service that is delivered to us over 'ATM' (it still arrives on a V.35 connection to a Serial on my router..., I have noticed a drop in my mrtg graphs of bandwidth utilisation at peak times of around 50kbits. Of course the point of going to ATM is to use a OC-3 interface and be able to scale well past 2Megs which we can't do until the Single Mode card arrives... Regards Shane ----- Original Message ----- From: Javier Henderson To: Dennis Cc: Alan Batie ; Sent: Tuesday, December 29, 1998 8:55 AM Subject: Re: ATM WAN interface Dennis writes: > Note that ATM has a LOT of overhead (like 30%). so ATM over a DS3 > is not nearly the bandwidth of using straight HSSI or PTP. ATM is meant > as a medium that can be switched at high speed, but as a PTP mechanism > it is very poor. I've often wondered how well IP would do, throughput-wise, over ATM with its 53 byte cells. "Packet fragmentation overhead" comes to mind. I've never seen actual performance figures, however. -jav To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message