Re: [RRG] Re: Fast and sparse mapping?

[Brian E Carpenter <brian.e.carpenter@gmail.com>]

Tony,

On 2008-09-19 05:22, Tony Li wrote:
> More catch up... 
> 
> Brian wrote:
> |I fully agree, and what I'm suggesting is that the (sad) history of
> |the initial success of CIDR followed by the recent backsliding which
> |I call "the PI heresy" shows us that economics will always 
> |tend to create
> |a swamp, so we'd better engineer the system for a swamp. And 
> |in a swamp,
> |any benefit from aggregation is both limited and unpredictable. (Would
> |anybody like to predict the effect of the collapse of the US financial
> |system on BGP4 aggregation two years from now?)
> 
> 
> Do you really mean that?  Are you really suggesting that we engineer routing
> for 2^48 prefixes?  

No. I still believe that the natural limit is somewhere around 10 million
PI prefixes, or just conceivably 100 million, so my target range is
2^23 to 2^27.

> 
> 
> |True. But that is, to use the technical term, a crap-shoot, just as
> |BGP aggregation of adjoining PI prefixes is a crap-shoot. It will
> |be the exception rather than the rule; that's the nature of a swamp.
> |There are no natural economic forces that provide incentives for
> |aggregation.
> 
> 
> True.  The alternative is for us to remove the incentives to deaggregate (as
> best we can) and then to restrict things so that people can't hurt the
> system.
> 
> 
> |So I stick to my guns: we need to map the edge-swamp into a 
> |significantly
> |smaller core-swamp, or nothing will change. Relying on aggregation at
> |the edge hasn't worked for BGP, so why should it work for any form
> |of EID/RLOC mapping (regardless of terminology)?
> 
> 
> I'd argue that if there's a core swamp, you've already failed to scale.

Well, yes, I'd rather see pure PA in the core, but I fear that ship
has sailed.

    Brian

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