On Thu, 19 Aug 1999, Jeff Mcadams wrote:
> I can believe that with a 25xx or so...those things only have 68ec030
> processors...hardly beefy at all...they're also a very old design (10
> years?) at this point. I suspect the 26xx's (basically the newer
> replacement for the 25xx's) will give Linux a really good run for its
> money there. Not that this is terribly significant.
>
> To be really fair though...when you're dealing with packet speeds that
> these types of boxes are dealing with (a 25xx can do 2 E1's and a
> regular ethernet at wire speed), it doesn't take much to do wire speed,
> and latency just isn't that significant.
We've had an *amazing* number of performance problems with Cisco routers,
including 72xx routers. We've had Cisco tell us that 7200s only
officially support 3 or fewer high-speed (HSSI or FE) ports, and we've
seen performance numbers to back this up. Ciscos work very nicely as long
as the traffic they're handling fits into one of their optimization hacks.
As soon as you blow past their route cache, or find yourself dropping from
hardware switching to software ('process') switching, you'll discover that
you have a $30k+ box that can only handle 15k packets per second.
> Sure...hardware switches are gonna kick butt in switching...that's not
> really what I was talking about....you can take a Cisco router, and tell
> it to switch in all these ways...and some of these "switching" services
> are labeled so because they deal with things at the link layer, but are
> really only useful for routers, particularly in that group, VRRP.
Ditto :-).
> To try to pull this back on topic some. :) I'd really like to see some
> more switching services added to Linux. VRRP would be one that would be
> really useful for folks to routing on Linux. I'd also like to see the
> bridging support extended to be more flexible. I have a really bizarre
> thought that would be really cool to be able to use IMHO. :)
>
> For a server system (you can do largely the same with a router system,
> but my use for this would be for a server system), put two nics in
> it...connect each nic to seperate network switches. Let the nics run
> briding code so they participate in spanning tree. Also "bridge" the
> traffic to a loopback or "virtual" interface or so (maybe you can
> already do this? haven't gotten a good answer, don't think so though),
> so you can tell daemons and such to bind to the loopback or virtual
> interfaces and the system can transparently recover from a dead nic card
> or cable, or switch.
>
> I've mentioned this to several people and quite a few of them just
> didn't understand what I was getting at...several others thought I was
> just weird (which is quite possible, even quite likely I'd say), and a
> few thought it was a neat idea.
I've wondered about this too. I brought it up in a BOF at LISA last year
and got a lot of confused expressions from people :-). I don't really see
why it wouldn't work, though, except the spanning tree time may be too
slow to be useful. Also, you can accomplish more or less the same thing
with dynamic routing and proper network design. The thing is, the layer 2
spanning-tree hack is much more locallized than the layer 3 /32 dynamic
routing hack.
Scott
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