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

[Robin Whittle <[e-mail]>]

Hi Paul,

I am replying to your message

  Re: [rrg] 2 Possible Consensus Items
  http://www.ietf.org/mail-archive/web/rrg/current/msg06277.html

in this earlier thread:

  http://www.ietf.org/mail-archive/web/rrg/current/msg06163.html

since you were discussing Geoff Huston's research and the question of
the current interdomain routing system and its routers scaling.

Geoff's research is:

> In the "Re: [rrg] draft-narten-radir-problem-statement-05.txt" thread
>   http://www.ietf.org/mail-archive/web/rrg/current/msg06152.html
> 
> and in "BGP in 2009":
>   http://www.potaroo.net/presentations/2010-02-01-bgp2009.pdf

You wrote, in part:

  It's possible that the current architecture of the internet is
  holding back growth that should otherwise be there.

Yes.  If we concentrate only on non-mobile networks, there are two
broad aspects of the routing scaling problem:

  1 - The unreasonable, arguably unscalable, burden placed on the
      DFZ routers individually, and on the DFZ control plane in
      general, by the set of end-user networks which currently
      get portability, multihoming and inbound TE by the only
      means available: getting their own space and advertising it
      as PI prefixes in the DFZ.

  2 - The much larger number of end-user networks which could use 2
      or more ISPs and which want or need portability, multihoming or
      inbound TE but don't have it because they are unable to get the
      space and advertise it.  (Perhaps a subset of these could do
      it, but don't because they known how unscalable it is.)

The growth in BGP advertised PI prefixes is the simplest measure of
the first aspect - which is like the tip of the iceberg.  The less
visible part is point 2, like the main body of the iceberg.

Then there is mobility - which has a prominent place in the RRG
Charter's description of the routing scaling problem.  Broadly
speaking, mobility is a whole other iceberg, so far completely submerged.

So even if Moore's Law keeps up in some acceptable manner with the
pace of growth in the number of PI prefixes in the DFZ, this doesn't
help with point 2 or with mobility.


Sorry I haven't had time to revisit our discussions in early
February.  I have a backlog of RRG messages to read and respond to -
mainly discussion following from my critiques of several
architectures - and I need to give priority to paying work.

  - Robin