Re: [lir-wg] Discussion about RIPE-261

[Aleksi Suhonen <]

Hello,

I know I'm responding to an old email, but I can't resist pointing
out a small but common fallacy here:

Quote from Andre Oppermann:
} In 1993 I was the
} proud owner of a i386sx16MHz PC with 1MB of RAM. Today I've got two
} GB of RAM in the very PC I'm writing this email on. What the heck,
} I've could even stick four GB in there, it's only EUR320 nowadays.
} About the price of an average high level 3d graphics card for gaming.

Routers -- and especially L3-switch-routers -- tend to use content
addressable memory (CAM) or other such specialized architectures
instead of dynamic random access memory (DRAM) to store the
forwarding table on NICs. The production numbers of DRAM chips are
orders of magnitude larger than those of CAM chips, and the gap
is getting bigger. These technologies are also way more complex
than DRAM to begin with. This means that the same amount of memory
takes up a lot more silicon real estate which is exponentially
relative to chip cost.

Using just DRAM is not an option either because you cannot build
the whole Internet on small-to-medium size routers with slow line
cards. Some operators will always outgrow them and those operators
will be the ones who in the end dictate how things are done.

This doesn't actually have anything to do with my personal view
on routing table growth. I'm just saying that there is a real
technical reason to be worried about it. CAMs (et al.) are getting
larger every year of course but, to the best of my knowledge, they
are not doubling in size every year as per Moore's law. To quote
Frederick Brooks, I don't think there will be a silver bullet to
this problem.

--
	Aleksi Suhonen / Axu TM Oy
	Internetworking Consulting