RE: multi homing pressure

Imagine instead, a world where Routing Location Identifiers
are not coupled to End System Identifiers and Interdomain
routing (AS-AS routing) occurred based on Routing Location
Identifier, and only Intra-AS routing depended on the
End System Identifier.

For example:

Host A connected to ISP X then ISP Y to ISP Z which
provides service to Host B.

Today, A, X, Y, Z all need to know how to reach B.

If we separated the RLI from the ESI, then, the fact
that B is reached via Z only has to be available
information that can be looked up by A, and, X
and Y only need to know how to get to Z. Only Z
needs to know how to reach B. This allows the
amount of data kept by each point along the way
to be much smaller.

Interesting. So Host A needs a lookup mechanism. If
I'm ISP X, then I'm providing a lookup server? You'd
need to figure out how to provide locally-significant
lookup results for topologically diverse hosts (A).

No.... ISP X needs to be able to look up a mapping
for Host B->Z or B->{G,H,Q,Z} or such. Much like
a Name->A record lookup occurs today, but, with a
more authenticated/secure protocol.

Further, since this is a "What ASs are proper termination
points for B?" question, it's not locally significant
to A (or locally significant at all).

What if X and Y (or Y and Z) connect at multiple points?
Would you hot-potato or cold-potato? Can you provide a
TE knob for that?

Yes... This would be router dependent, but, it is do-able.
Instead of X knowing how to reach prefix Y.B and prefix Y.C
and prefix Y.D, X would know all the ways to reach Y.
TE would involve some mechanism for deciding which portions
of traffic destined to Y use which path, and, in this
case could be based on prefix or on some other method.
Specifying the methods is outside of the scope of this
proposal, but, examples could include: round robbin,
shortest queue, least recently used, prefix hashing,
flow hashing, etc.

It would be interesting to see a table showing how often
various routes are looked up. I suspect that a
significant portion of routes are seldom, if ever, used
by most parts of the network, and therefore don't really
need to be held and recalculated except on-demand. But

Exactly, and, which significant portion that is is different
depending on where on the network you are.

I'm not currently equipped to do that analysis, and it
would be completely different depending on where you are
in [your | the] network.

Exactly. That is why I think that global knowledge doesn't
and can't scale in the long run. Currently, we are approaching
routing the same way we used to approach name->IP mapping.
(Remember the days when the /etc/hosts file was FTPd from SRI?)
DNS is a much more scalable solution for that problem.
I think that routing can be done on a similar basis.