>
>Quite simply, a bunch of us *are* searching for a paradigm shift. Geoff's
>good work in this area reveals the complexity of the whys and wherefores
>of the routing system. Given that 8+8 was a serious consideration (and to
>some deserves some amount of revisiting -- at least as a starting point),
>I don't believe we can say that the deployment of v6 is completely
>divorced from the routing system. 8+8 is merely an existence proof of how
>the routing system and v6 can be intertwined, for better or worse.
As I tried (probably poorly) to indicate in my last posting on this topic
there are a number of different directions you can take when searching for
a lever to use to handle scaleable routing. Our recent experience with V4
using an address-based hierarchy tends to indicate that the hierarchy leaks
- i.e. attempting to align the structure of the network into a hierarchy
and aligning addresses to conform to this same hierarchy is not an easy
task and it tends to break down in the face of increased interconnectivity
at the edge (multi-homing) and in the middle (peering and multi-transits).
If you look away from an address -based hierarchy and define other objects
as the 'atoms' of a routing system then there may be some benefit. Even
today, with some 105,000 objects in the routing table (*) there are only
some 12,000 AS's (*) and 15,500 AS paths selected (*). This tends to
indicate that grouping addresses not by bit boundaries, but by origin AS's
has some potential, in my view (*). If you take this AS-based perspective
the issue of V4 / V6 tends to be less important than if you take an address
hierarchical perspective. I note the AS-based approach to hierarchies as an
example - there are other ways to look at the network that also provide
some tractable level of grouping that could make interdomain routing scale.
The point is that the degree to with the inter-domain routing issue is
intrinsically liked to the address structure within the protocol depends on
the approach used by routing. Some approaches, like an AS-based approach,
attempt to bypass an effort to structure the address space as the
aggregateable element of the routing system, and the corollary is that the
approach has pretty much the same leverage in a V4 world, a V6 world, or a
heterogeneous world.
Geoff
* Your mileage may vary.
