Date: Thu, 19 Sep 1996 10:27:37 -0500 (CDT) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: rls@mail.id.net (Robert Shady) Cc: jfarmer@sabre.goldsword.com, dennis@etinc.com, nik@blueberry.co.uk, isp@freebsd.org, jfarmer@goldsword.com Subject: Re: Routers - hardware received wisdom Message-ID: <199609191527.KAA10968@brasil.moneng.mei.com> In-Reply-To: <199609191427.KAA09043@server.id.net> from "Robert Shady" at Sep 19, 96 10:27:20 am
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> > 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
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