This would also indicate the timeframe needed for deployment of software to support 4 byte AS numbers. FYI, recently issued AS numbers have been in the 22XXX area.
Much of this thread appears to be operating under the flawed assumption that the only ways to multihome[1] involve inserting prefixes of some size (under dispute) into the global[2] routing table. Sure, at the moment, that is predominantly the way things work. But beyond bitching at eachother about filtering policies (which has a long record of productive results... mmm...), consider technologies that can change this. Well, let's assume the routing table remains static across a failure (and hence we don't have to introduce prefixes). We need some technology which acts as an indirection mechanism in the case of a failure. One such technology possibly ripe for perversion is DNS. Another is mobile IP. Sure, these may not be great for the application right now, but they both share a key advantage, which is that the deployer pays (not the rest of the internet). Assuming the a fixed % of users multihome (and it's likely to increase), and assuming a fixed cost per prefix supported (OK, so that's likely to decrease), the costs are O(n) rather than O(n^2). And some of these technologies have other advantages. BGP traffic engineering is difficult (tm), in that it is is almost impossible to present a list of 2-tuples (correspondant, pipe), and get BGP to work that way in anything other than the outbound direction, and dynamic traffic management (responding to congestion) is hard. Indirected technologies (DNS being an obvious one as it exists, though it's less than ideal), don't have to suffer the same limitations. [1] = let's define that, for convenience, as to connect to n>1 different providers of IP connectivity, possibly utilizing redundant tail circuits, in a manner where if one or more, but not all providers fail, service is degraded as little as possible. [2] = less than global, if it becomes balkanized filtering in response to uncontrolled proliferation of long prefix routes -- Alex Bligh Personal Capacity