Re: Fallacy by Kurt (was Re: IPv6 Policy Clarification - Initial allocation criteria "d)")

[Gert Doering <gert@space.net>]

Hi,

On Tue, Jun 22, 2004 at 09:18:05PM +0900, Masataka Ohta wrote:
> Gert Doering wrote:
>
> >>>>In favour of *what* to replace it?
> >>>
> >>>RIR membership.
> >>
> >>No. It is proven not to scale.
>
> > "Proven"?  When, where, by whom, based on what data?
> > There are less than 10.000 LIRs in existance today, all RIRs combined.
> According to my upper bound, it's already unnecessarily too large.

So the *proof* mentioned above consists of "your personal feelings what
the upper limit on the routing table size should be"?

While I honour your feelings (I also think that the routing table
shouldn't grow out of bounds), this is no "proof" that it's not going
to scale.

Also it brings back the problem of "who is worthy enough to receive
one of 8192 TLAs", which was abandoned some 5 years ago, because there
is no entity that can make this decision.

> > 10.000 routing table entries is something far below the near 140.000 we
> > have today in IPv4.  While I'm seriously unhappy with the 140.000 IPv4
> > routes, it *does* scale up to fairly insane numbers.
>
> Of course, you can have as many routing table entries as you want,
> as long as backbone routers, speed of which degrade as their routing
> table bloat, have large enough routing table.

Of course.  But I tend to believe if people tell me "10k routes are no
problem today".  Oliver is building routers, with fast memory, and
good routing table lookup algorithms.

Today, high end routers can handle 140k routes.

[..]
> If the size of global routing table is limited by a hard upper
> bound, it simplifies the design of routers a lot (you can put
> a backbone router (or many of them) with a global routing table
> in a chip), reduces cost of routers a lot and increases speed
> of routers a lot.

This is not going to work.  *Inside* your AS, you will always have
some more routes, and depending on the quality of your IGP aggregation,
you might easily end up with more than 10k *internal* routes.

So no matter what upper bound you put on the external routes, you
cannot assume that nobody will ever need more routing table entries.

Out of interest: what number do you suggest for the hard upper bound?

> Note that, for scalable (thus, end to end) site multihoming properly
> work, all the sites are required to circulate global routing table
> within the sites.

Actually, no.  Not even in IPv4 today (which is part of the problem,
that you can inject your prefix from a Cisco 2500 router, while
everyone else needs to buy $costly hardware to *carry* your prefix).

Gert Doering
        -- NetMaster
-- 
Total number of prefixes smaller than registry allocations:  60210  (58081)

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