What is the limit? (was RE: multi-homing fixes)

Wed Aug 29 22:44:56 UTC 2001

On Wed, 29 Aug 2001, Roeland Meyer wrote:

> Sorry, Leo is correct. Technologies he outlined are only the tip of the
> ice-berg of what *isn't* being exploited by the router vendors.

Your average PC doesn't have to be NEBS-compliant, doesn't have to work
more than 24 hours w/o crashing, and doesn't have quite strict constraints
on power & heat dissipation.  It doesn't have to have redundant power, and
its components are readily available and cheap (those are produced in
_large_ batches).

Using the "latest and greatest" in routers is not as easy as it seems.
First of all, when you get a new CPU you typically get a pre-packaged set
of peripherial chips (memory controllers, I/O bridges, etc) which are OK
for building a PC but patently useless for building a router with its
special needs for I/O performance.

So then you have to build custom chips around the CPUs; and you just
cannot get any useful advance information from CPU manufacturers because
they do not want to undercut their business in peripheral chips (as will
happen if their CPU interface specs leaked).  You have to wait until the
actual chip is released (or close to release).  PC manufacturers do not
worry abouth those things - they get ready-to-use reference motherboard
designs, together with chip bundles; initial prices are high, and then
companies in Taiwan start to reverse-engineer the stuff and drive prices
lower.

And don't get me started on heat and airflow issues :)  Reason #1 why
Pluris abandoned the original idea of using commodity CPUs was heat, not
the switching speed.

--vadim