Re: [rrg] Geoff Huston's BGP/DFZ research - 300k DFZ prefixes are the tip of the iceberg

[Paul Jakma <[e-mail]>]

On Sun, 14 Mar 2010, Tony Li wrote:

> Actually, no growth in prefixes does not imply that there is no growth in
> the Internet.  You can still add customers within existing prefix
> allocations and improve your addressing efficiency.

Hehe, My implicit assumption is that there's no significant change in 
allocation densities. :) Stuff like that generally seems to be an 
administive issue, so it's maybe unlikely it can be affected through 
routing changes.

> First, no one is claiming that there is an imminent and urgent 
> problem. What I feel that we've shown is that we have a long term 
> systemic problem. Given that truly dealing with this issue does 
> appear to require major amounts of time to deploy, it only seems 
> reasonable to start dealing with it long before it becomes an 
> urgent problem.

> Please see my RAWS presentation.  It shows that prefix growth 
> exceeds the speedup that we can expect in DRAM.

I remember reading that.

> This in turn implies that BGP will take longer to converge at a 
> given node when that node has to process the full table.

That's the thing though, the most recent data doesn't seem to show 
any evidence of things like that. If per-node convergence was taking 
significantly longer (in the "scaling badly relative to prefix 
growth" sense), then Sigma(per-prefix per-node convergence) should be 
similarly increasing by at least the same amount and BGP observers 
ought to be able to see that, and so the data should show it.

Yet it doesn't seem to, right?

Further, even if the growth issues only affected a certain subset of 
prefixes, surely there'd be "side-band" issues. I.e. processing 
problems with certain prefixes should adversely affect the processing 
of other prefixes being processed around the same time.

I'm sorry for being such an arse with my scepticism, and I'll 
understand if people reply to me as if I'm half-wit, but if scaling 
is a problem surely it should be apparent in some data somewhere over 
the last decade+ that people have been worrying about it? Where's the 
smoking gun graph, based on real data, that shows the scaling 
problem? I'm somewhat willing to take your word as authoritative, but 
ideally we'd have graphs :).

I stress again that, despite taking this contrarian view of the 
scaling problem, I still think the work here is very important!

I just think this question must have a big impact on which classes of 
solutions are and are not viable.

regards,
-- 
Paul Jakma	[e-mail]	Key ID: 64A2FF6A
Fortune:
We don't understand the software, and sometimes we don't understand the
hardware, but we can *___see* the blinking lights!