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RE: Regionally aggregatable address space for multihoming
Brian E Carpenter wrote:
> Also the cost pressure is going to be against local exchanges
> and in favour of large regional exchanges. Given this (and
> other points noted below) I don't see that geo addressing buys us
> anything much at all, certainly not orders of magnitude.
Take the example of just an 8-bit prefix using my proposal. The globe
divides into 128 regions, with 68 unusable (32 are polar, 36 are basically
water). Of the remaining, I count 16 that map into current
telecommunications centers. While some neighboring regions may find it
advantageous to leak full routes between themselves, there should be at
least 12 that end up summarized. Yes a region has flat routes, but it
doesn't need more than 3/4 of the table, and will probably do better than
that. The interconnection robustness at this scale is fairly high, so we
could get some gain. Within the regions, it becomes a mater of local
politics and business practice as to how much further the plan can go.
Certainly it will be more difficult in either Europe or the US than all the
others combined, but if you write off those 4 regions as hopelessly
intertwined there is still an opportunity for significant gain in the rest
of the world.
> The only safe design target is 100% of all businesses
With a geo plan you get 'all sites', and don't need to worry if it is a
business or not.
> Not if the solution is worse than the problem. I believe that
> geo addressing simply reproduces pre-CIDR IPv4, since it is based
> on unrealistic assumptions about inter-ISP connectivity.
Only over a given scope. The CIDR roll out effort also showed what
backpressure from the top could do to constrain entropy. It also showed what
happens if you push too hard. When you try to over-engineer and enforce
controls for maximum optimization you will loose control and be back where
you started. This is where the rewriting the goop plan falls flat, because
they are targeted at absolute optimization in the middle, without concern
for systemic impact.
> Only if you revolutionise ISP interconnection strategies and
> find some way to change the underlying economics.
Geoff Huston should be stepping up to this one. There is no need to change
human nature, just provide a reasonable tool for aggregation then charge for
carrying explicit routes when people insist on them. Match the economics to
human nature rather than trying to invent a technological restraint system.
> Don't misunderstand me - we need a radical solution. I just
> don't think that geo addressing, which is fundamentally the
> telephone solution, is radical enough.
It may not be for the long run, but we need something to get IPv6 off the
ground in the mind of ISPs. So far they are complaining that it offers
nothing to solve the immediate scaling problem with provider based
addressing; so the obvious step is to remove all reference to provider from
the address. Other than cases of enforced portability, this is not the
telephone model. There, as the address space was divvied up, the provider
boundaries happened to align with a political notion of geography. A WGS-84
based plan is even devoid of political boundaries.