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

  • From: Roeland Meyer
  • Date: Wed Aug 29 13:13:44 2001

|> From: [email protected] [mailto:[email protected]]
|> Sent: Wednesday, August 29, 2001 8:06 AM

|>   Draw two curves, the first y=x/2, the second y=x^2
|> Move the value of x for y=1 for the first curve left by 2, 5 or 10
|> and it will still be surpassed by the second curve.
|> You will even see this for a second curve of y=x*2 or y=x.

Prove it. 

|>   The global routing table size HAS grown exponentially 
|> in the past.   Rationalize it any way you want, blame whatever
|> you like, but there is no known way to construct a router that
|> can handle that kind of growth in anything but a short term,

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. Yes, my
2-year old Dell lap-top has more horse-power than your average Cat 3524XL.
But, sadly, it doesn't have the I/O capacity. However, one of my
tight-fisted dot-com clients (why they're still in business) had me build
three 1U 8-port, router/switchs, built from COTS commodity parts. It worked
at line-speed. Code was courtesy of the Linux Router Project (open source).
At retail prices, the entire parts cost was less than $6KUS each. Specs
were, dual PIII-866, 2GB RAM, 1 CDROM boot drive (no HDD), three 4-port PCI
100baseTX PCI cards, 1U rackmount case. 1 week for the build and two for the
software. It still cost less than equivalent Cisco purchase. Yes, I tried to
sell them Cisco Catalysts instead. To some extent, Cisco deserves what's
happening to their stock prices right now. [ side note: one of the biggest
benefits of the, non-proprietary, open source Linux movement is that it lets
me do *real* computer engineering again]. 

Yes, the routing vendor's largest advantage is proprietary back-plane
design, optimized for I/O. But, with ASIC technology today, and most
importantly, modern macro architectures, one works around that easily. I had
plenty of capacity to add DNS zone server software and web-based
administration with server-side Java. I had seriously considered
productizing it, but in the current economic climate, no one is funding such
projects, yet. BTW, this was built almost a year ago. They're still online.
Note that PCI bus technology is more than 10 years old. We can do better if
we want to and if there's money in it.

|> and the trend for the components in the router growth curve
|> is simply not going to increase to a long term superlinear rate.

That trend is set very much by the router vendors. They have deliberately
held growth down in order to keep prices inflated. They can do this because
there aren't a whole lot of real computer engineers around anymore.
Everyone's a specialist these days and very few do engineering at the macro
level, they're called Computer Architects. Many of us *don't* do the IETF
thing because we'd rather get paid for our work. In the real world, prestige
don't pay the rent.

The router vendors have done a real good job convincing everyone that they
are at the state-of-the-computer-arts. I've got a clue for you, they're far
behind it.

|>   A 10x system performance boost today just moves the x point for
|> y=1 of fundamental curve claimed by Moore's Law to the left 
|> a few notches.   Or are you claiming that routing equipment 
|> will have a fundamentally different, and larger, growth curve
|> than other computing systems?  (I think there is a basis for
|> claiming that there are some reasons which would support a 
|> _shallower_ growth curve for routing equipment, actually).

As said before, we could see a one-time step up, by more than an order of
magnitude. That alone should get us to the forseeable end of the IPv4 cycle.
Yes, I agree that we need to do something for IPv6...starting NOW!

|>   In short: are you claiming that the caeteris paribus assumption
|> in comparing Moore's Law to global routing table size is 
|> clearly false?   

That depends on how you apply *what* technology to the curve. It's only
proven by corrolary, no hard evidence is provided. I'm not convinced that
the given Moore's law curve is accurate. In the secular world of the router
vendor, they may think that they're on it. Simple observation shows that
they aren't. Why do you think that warranty terms prohibit pealing open the
$10KUS box?