[ppml] Free Market

Iljitsch van Beijnum iljitsch at muada.com
Sun Aug 26 10:13:18 EDT 2007

On 26-aug-2007, at 3:16, David Conrad wrote:

> "All PI" and "all PA" are merely theoretical extremes of the
> aggregation continuum.  Right now, political/economic pressure is
> pushing us towards the PI side.  Once it gets far enough to that side
> that people begin to seriously worry about their routers falling
> over, ISPs will take what steps they feel appropriate to protect
> their own infrastructure.

Unfortunately, the way things are set up now, the only way to do that  
is very destructive: by kicking prefixes out of the routing table.  
And since all PI and PA blocks sit at the top of the aggregation  
hierarchy, once you filter such a prefix, it becomes unreachable.

However, if we start giving out address space hiearchically, it is  
then possible to choose a level at which filtering happens and it's  
still possible to have reachability, although obviously things will  
have to work slightly differently than we're used to now.

On 26-aug-2007, at 2:33, William Herrin wrote:

> The criminal part, though, is it consumes so many bits that it
> forecloses the possibility of solutions to PI

Then you're not trying hard enough. It's entirely possible to create  
a hierarchical addressing model with only a modest fraction of the  
IPv6 address space. In this, I'm using (basically) two levels within  
32 bits, which gives between 1 out of 4 to 1 out of 10 people on the  
planet a /48 PI block using only a /16:


Cue objections to geography in routing... However, you get to ignore  
geography if you don't want to aggregate, so if you can afford those  
big routers, it costs you nothing and it provides some insurance  
against the possibility that you won't be able to afford the big  
routers in the future.

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