From owner-freebsd-isp Fri Jul 11 05:59:02 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id FAA05571 for isp-outgoing; Fri, 11 Jul 1997 05:59:02 -0700 (PDT) Received: from mail.id.net (mail.id.net [199.125.1.6]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id FAA05562 for ; Fri, 11 Jul 1997 05:58:55 -0700 (PDT) Received: from server.id.net (server.id.net [199.125.2.20]) by mail.id.net (8.8.6/8.8.6) with ESMTP id IAA20248; Fri, 11 Jul 1997 08:59:05 -0400 (EDT) From: Robert Shady Received: (from rls@localhost) by server.id.net (8.8.5/8.7.3) id IAA19275; Fri, 11 Jul 1997 08:59:03 -0400 (EDT) Message-Id: <199707111259.IAA19275@server.id.net> Subject: Re: T1/T3 Upgrade Options? In-Reply-To: <3.0.32.19970710175730.00b07380@etinc.com> from dennis at "Jul 10, 97 05:57:33 pm" To: dennis@etinc.com (dennis) Date: Fri, 11 Jul 1997 08:59:03 -0400 (EDT) Cc: rcramer@sytex.net, isp@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL31H (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-isp@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk >>> Well, I wasn't going to do this, and probably shouldn't have, but here's >>> the situation. We all know that you can use the ET-Inc card or the >>> SDL card for T1 routing... But does FreeBSD have ANYTHING available with >>> a HSSI interface yet? We've already bought one Cisco 7010 and the $60,000+ >> >>Yes. Both SDL and DEC have cards available. If you need particulars, or >>are not a system integrator, you may email for more particulars. Yes, I would like more information please... Does FreeBSD have drivers available for these cards already? Or would we have to code one... > Just to know that we can do at least 10Mbs on a clocked down T3 via V.35 > (Digital link make a CSU)...if you're metered and running full T3 we can't > do it (yet). This completely contradicts what you say below... If a PCI bus can't do T3, why would you make a card that could? > A major factor to consider is that its very difficult to do 86Mbs (T3 is > full duplex) with an addon card on the PCI bus because the sustained > throughput rate is often pretty low. Other bus masters (ethernets, for > example) will futhur reduce the burst capability. While PCI bursts to > 128MB/s, very few PC products have sustained throughput rates over 100Mb/s. > If you have a 100Mbs ethernet card on the same bus (you'd have to) the > number is cut in half. plus bus masters can't be controlled so you have > contention issues. Contention issues I'll agree with for the most part, however.. My calculations are (correct me if I'm wrong): T3 Card = ~12Mbytes/sec [ 45Mbits/sec (each direction), or 90Mbits/sec total] Ether = ~25Mbytes/sec [100Mbits/sec (each direction), or 200Mbits/sec total] ============= ~37Mbytes/sec 132 Mbytes/sec - PCI bus - 37 Mbytes/sec - Interfaces ================ 95 Mbytes/sec - Left to play with. The way I see it, you theoretically could have 3 100 Mbit interfaces AND a T3 card running simultaneously (specially since it's not likely you'll ever push a true 45Mbits/sec each direction on a T3). However, the real problem comes into play trying to find a CPU that can handle that many interrupts per second effeciently. -- Rob === _/_/_/_/_/ _/_/_/_/ _/_/ _/ _/_/_/_/_/ _/_/_/_/_/ _/ _/ _/ _/_/_/ _/ _/ _/ _/_/_/_/ _/ _/_/_/_/_/ _/_/_/_/ _/ _/ _/_/_/_/_/ _/ Innovative Data Services Serving South-Eastern Michigan Internet Service Provider / Hardware Sales / Consulting Services Voice: (810)855-0404 / Fax: (810)855-3268 / Web: http://www.id.net