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Re: [RRG] Idea for shooting down
On 2007-11-25 10:47, Iljitsch van Beijnum wrote:
On 23 nov 2007, at 20:32, Brian E Carpenter wrote:
I think your scheme is not needed - a single BGP system and a
single ITR-ETR system should do the trick.
We differ ;-). I don't think we can add anything to our arguments,
so I'd like to know what other people think - one level
vs several levels.
Since you ask: what I would like to see is a combination of something
from the LISP family combined with a hierarchical mechanism like CRIO
that allows packets for which there is no mapping yet to be delivered
through increased stretch.
The number of levels in the hiearchy would presumably be greater than
one, but this is something that the operators should figure out.
I'm not sure I've digested all the elements of your IFSD (idea for
shooting down) approach, but in general, I'm suspicious of an approach
where there is emphasis on having different levels of an hierarchy that
isn't a natural extension of the addressing hierarchy because this
requires extra effort to find out where in the hierarchy a certain
prefix is present at any given time. An approach where the routing
hierarchy is aligned with the address bits seems a more natural choice
to me. But I'm open to hearing more arguments.
I really wish it could be like that, but I think all the history,
including pre-CIDR days and the modern PI heresy, shows that we simply
aren't going to achieve congruence between topology and address
structure. So yes, I guess I'm arguing that *if* we want a defined
hierarchy, it has to be orthogonal to address structure (which is why
I suggest borrowing some AFI bits to represent the hierarchy in the
maps).
Brian
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