Date: Fri, 26 Jun 1998 17:47:28 -0500 (CDT) From: Chris Dillon <cdillon@wolves.k12.mo.us> To: Ulf Zimmermann <ulf@Alameda.net> Cc: Atipa <freebsd@atipa.com>, hackers@FreeBSD.ORG Subject: Re: Will 8 Intel EtherExpress PRO 10/100's be a problem? Message-ID: <Pine.BSF.3.96.980626173407.14997A-100000@duey.hs.wolves.k12.mo.us> In-Reply-To: <19980626153112.B24252@Alameda.net>
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On Fri, 26 Jun 1998, Ulf Zimmermann wrote: > On Fri, Jun 26, 1998 at 11:03:01AM -0500, Chris Dillon wrote: > > On Thu, 25 Jun 1998, Atipa wrote: > > > > > > > > > I really hope -hackers is the best place for this... i didn't want to > > > > crosspost. > > > > > > > > Within the next few months, i will be needing to set up a router for our > > > > internal network, tying together 7 networks, with some room to grow. I > > > > plan on buying a rather expensive chassis from Industrial Computer source. > > > > It has an interesting partially-passive backplane with a PII-233 or faster > > > > and chipset mounted on it (LX or BX chipset, I believe) with everything > > > > else on a daughtercard and 9PCI/8ISA slots. Something like the model > > > > 7520K9-44H-B4 with redundant power supplies. > > > > > > Cool. > > > > > > > Basically my questions are: > > > > > > > > 1) Will there be any problems with using three or more host-to-PCI > > > > bridges? > > > > > > Maybe not in the kernel, but I'd start to worry about saturating your > > > buses. You are really bumping up against some I/O bottlenecks in my > > > estimation. > > > > I'm rather hoping that three 133MB/sec PCI busses won't have any trouble > > passing at max about 30MB/sec worth of data (10MB/sec per card, three > > cards per bus). Theoretically even one PCI bus could handle all 8 of > > those cards.. _theoretically_... :-) > > Double that number, Full Duplex is what you usual now use in routers. > I also wouldn't say the single bus is the problem, but the main PCI bus and > the CPU will be a bottleneck. You will definatly not be able to run 8 > cards at full speed (8 x 10Mbyte/sec x 2 (FullDuplex) = 160 MByte/sec) Doh.. I knew that, but didn't put that in my calculation. Anyway, I'm not needing full wire-speed from these things. I think I'd be happy with 1/5th that. :-) I'm expecting that if ftp.freebsd.org can do about, 5MB/sec on average, along with thousands of FTP clients, without breaking a sweat on a PPro200, then a PII-350 or 400 should be able to do line-speed at least between two networks at a time. If and when I do this, expect me to perform some benchmarks. :-) As for the "main PCI bus" being the bottleneck, I'm really hoping they used three host-to-PCI bridges, and not a single host-to-PCI bridge and two PCI-to-PCI bridges. Even if not, I could push about 100MB/sec across the bus (assuming the CPU could push that), and thats more than enough for me. I imagine a Cisco of _equal price_ wouldn't even come close to the throughput I'm going to do. I could be wrong, of course. > -- > Ulf. > > --------------------------------------------------------------------- > Ulf Zimmermann, 1525 Pacific Ave., Alameda, CA-94501, #: 510-769-2936 > Alameda Networks, Inc. | http://www.Alameda.net | Fax#: 510-521-5073 > -- Chris Dillon - cdillon@wolves.k12.mo.us - cdillon@inter-linc.net /* FreeBSD: The fastest and most stable server OS on the planet. For Intel x86 and compatibles (SPARC and Alpha under development) (http://www.freebsd.org) */ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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