[arin-ppml] Routing Research Group is about to decide its scalable routing recommendation

Michel Py michel at arneill-py.sacramento.ca.us
Sat Dec 19 03:25:02 EST 2009

> Leo Bicknell wrote:
> As I see it, the problem space has three, high level,
> diverging paths:
> A Multihoming happens entirely at the host, making
> PA-only possible.
> B The routing system can scale to PI, so everyone has PI.
> C Neither A or B is possible, so we attempt to decide
> who is worthy of PI.

There is also D: Dual space protocols (ID/LOC). None of them really got
traction in the IETF.

> It seems to me we are in case C now.

We are. And in the case of IPv6, we are because the RIRs passed policies
to allocate PI to non-LIRs, not because the IETF wanted so.

> the IETF tried A several years ago and gave up, and the
> IETF is now trying B. (roughly)

I don't think that the IETF gave up on A. And although the IRTF is
looking at B, there still is a long road before it gets traction in the

> Which raises an interesting question, why hasn't SCTP taken off more?

I have met in person with some of the guys heavily involved in SCTP ways
back when; very interesting work. I think that in the end the reason it
has not taken off more is basically the same reason none of the
host-based multihoming solutions has taken off either: too complex.

Anything that involves multiple addresses per host and heaven forbid
even worse multiple interfaces per host is a nightmare to TE and
troubleshoot. Imagine trying to troubleshoot a network issue with your
typical tech support subcontracted overseas when the thing involves
multiple interfaces with multiple addresses crossing multiple backbones.
Good luck; as of today there are no tools for this and no money to build

Sadly, nothing matches the raw simplicity of this unique PI prefix that,
unfortunately, makes the DFZ big.


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