Re: The state of IPv6 multihoming development

[Iljitsch van Beijnum <iljitsch@muada.com>]

On Fri, 25 Oct 2002, Masataka Ohta wrote:

> > I figured the whole geographical aggregation thing was a step in the
> > right direction...

> A problem is that such geographical aggregation can not properly
> handle multiple links between regions maintained by multiple entities.

Regions aren't "maintained" by "entities". You simply route traffic for
a region to a router inside your own network that has more specific
routing information for the region. Obvioulsy, it makes sense to put
that router inside that region, but you don't have to.

> Another problem is that it is helpless for a partitioned geographical
> area.

You can deaggregate. But automatic deaggregation is dangerous, so yes,
partitioning is bad. This means you must define your regions in such a
way that it is very unlikely that they will be partitioned internally,
from the rest of the network or from peers in the region. This makes it
hard to arrive at very small regions which in turn sets a practical
limit on the scalability of geographical aggregation. In theory, it can
scale to 1G multihomers. In practice, it won't be much fun anymore
beyond 25 - 100M.