From owner-freebsd-isp Thu Sep 19 08:31:35 1996 Return-Path: owner-isp Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id IAA25045 for isp-outgoing; Thu, 19 Sep 1996 08:31:35 -0700 (PDT) Received: from brasil.moneng.mei.com (brasil.moneng.mei.com [151.186.109.160]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id IAA25018 for ; Thu, 19 Sep 1996 08:31:30 -0700 (PDT) Received: (from jgreco@localhost) by brasil.moneng.mei.com (8.7.Beta.1/8.7.Beta.1) id KAA10968; Thu, 19 Sep 1996 10:27:38 -0500 From: Joe Greco Message-Id: <199609191527.KAA10968@brasil.moneng.mei.com> Subject: Re: Routers - hardware received wisdom To: rls@mail.id.net (Robert Shady) Date: Thu, 19 Sep 1996 10:27:37 -0500 (CDT) Cc: jfarmer@sabre.goldsword.com, dennis@etinc.com, nik@blueberry.co.uk, isp@freebsd.org, jfarmer@goldsword.com In-Reply-To: <199609191427.KAA09043@server.id.net> from "Robert Shady" at Sep 19, 96 10:27:20 am X-Mailer: ELM [version 2.4 PL24] Content-Type: text Sender: owner-isp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > > I think that Dennis' comment & what Joe said in his note answered a question > > that I've had lurking in the back of my mind, "Just what is sufficient to run > > a FreeBSD T-1 capable router?" > > > > Granted that a no-name MB & 133Mhz 486 is running around $120, but I > > "happen to have" a 386/33, 8mb, 300mb disk sitting in the corner, with > > an ethernet card in it (isa only :^,). And I have a need for a T-1 capable > > box soon. Since it would be a fairly un-saturated T-1, I suspect that > > I will be able to get away with it for a while... Then the question becomes, > > how many 56/64k/128/256k frame relay links could a "little" box like that > > handle? (Must be the Scots in me, I hate to throw away anything!) > > Let's think about this logically people.. We're only talking about a MAX > of 187 Kilo-Bytes per second for a single T1 line... I've got calculators > that could max that out! Now.. When you start throwing multiple ethernet > devices in there, and you want to provide wire-to-wire speed acrossed those, > that is another story.. We're using a 486DX4-120Mhz w/32MB of RAM here, and > it is running 3 100Mb Intel Etherexpress cards, and 2 10Mb SMC Elite Ultra > cards.. It does a decent job, although I don't know that I would expect to > be able to get full wire speeds on all ethernet cards simultaneously.. But > luckily, we have enough segments and switches that we don't need to worry > about that, yet. Rob, With all due respect it is not that simple. I suspect that with MTU-sized packets, I can easily go wire to wire with 10baseT at peak speeds even on a 386DX/40 with SMC ISA cards. Actually I was doing that at one point, IIRC, and it worked fine. I suspect that with very small packets, the same machine will have abysmal performance. Dennis' T1 sync serial cards are most similar to an Ethernet card, and I will flat out state that I can saturate your DX4/120 CPU before I hit T1 saturation if I attempt to saturate that T1 link with miniature packets. I have saturated a DX5/133 with this test and it is ugly. On the other hand, the router on the other end was clearly swamped and was only returning one packet for every three I sent (I could see it on the CSU/DSU lights, it was not due to my local CPU being saturated). Some Livingston piece of junk, I believe. It is clearly very dependent on the kind of data you send. I think I can floor even a large Cisco with the right kind of abuse so maybe it's a pointless discussion. I will certainly be the first in line to say that I was pretty happy with a 386DX/40 as a T1-Ethernet router... but I will also be the first to properly qualify that statement. ... JG