[Dundi] advertising for peers

[Mark Spencer]

> 1. It makes no sense to me to impose regional conventions on telephone 
> numbers on a system which is designed to connect regions, not provide 
> connectivity within them. So, every reference to regionalisms such as area 
> codes, LATA, NPA, NXX should be removed from peoples' minds, and they should 
> instead concentrate on advertising collections of E.164 numbers ("routes", 
> right? I'm a packet guy, normally).

Okay, lets clear up a few things:

Everyone knows that the real question of DUNDi is how well it will scale. 
Suppose that the e164 trust group were strictly structured such that it 
was in fact heirarchical (e.g. there were 10 strongly connected nodes in 
the center with each digit 0-9, then 10 connected to each of them, 0-9 and 
so on, it would be essentially identical to ENUM.

The goal is to try to keep systems whose numbers are *similar* in the same 
branch of the tree in order to maximize the value of the cached answers 
and hints and make the system as scalable as possible.

To facilitate this, we obviously need real documentation on what everyone 
has and so on.  I'll try to do some restructuring to help with that.

> analyse my telephony costs, and if I notice I'm terminating a lot of calls on 
> +441234, I want to hunt for peers that can service those numbers.

It *does not help* to peer with people whose numbers you tend to call, and 
it's REALLY not good to connect branches of the tree anywhere but at the 
center (loops are extremely bad for cache).

> 3. The decision as to whether entity A should peer with entity B seems like 
> it is all about the relative, respective usefulness of the routes available 
> to those two entities, and has very little to do with designations of 
> "tier-1", "ISP", or notions of available bandwidth.

It has nothing to do with how often you call them *because* the entire 
system must always be queried for every number conceptually.  The 
challenge is to make the actual behavior NOT look like the conceptual 
behavior, by bringing similar numbers together and maximizing the cache 
behavior.

Mark