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Re: [RRG] Tunnel fragmentation/reassembly for RRG map-and-encaps architectures
On 2008-01-10 12:15, Tony Li wrote:
On Jan 9, 2008, at 2:11 PM, Brian E Carpenter wrote:
Can we clarify that conceptually we are talking about prefixes and not
individual interface EIDs, as far as the full map goes?
(Except, presumably, for a few special cases such as root servers.)
Well, this should spark some useful discussion... ;-)
Sorry, no, I don't think that you can make that assumption without a lot
more justification and/or consensus building. There are large
organizations (you used to work for one of them, I believe ;-) where
there are multiple Internet connections that have geographically widely
dispersed contact points.
Correct. And that is a significantly harder problem than multihoming
for an enterprise network that only has one point of interconnection
to the outside.
Optimal routing implies that there will be
different locator preferences for different hosts. Mobility within the
organization itself implies that creating and maintaining meaningful
identifier prefixes is going to prove challenging.
Indeed it is challenging, so why bother? Having roamed around that
organization pretty widely over ten years, and roamed around it
virtually by remote VPN on a daily basis, I never had or needed
a meaningful prefix beyond 9/8. Internal servers, otoh, don't roam.
Externally visible servers aren't even in Net 9, because of various
techniques for security, load balancing, and traffic management.
Certainly I'd expect EID space for large enterprises to be sliced
and diced down to the geographical-site or even server-farm level.
I don't think it's necessary down to host level.
In other words, I think that we need host level granularity in the
mapping function.
I'd prefer to say: we need to support arbitrary granularity, but the
normal level will remain as a site (for some definition of site).
I wonder who's correct ?-)
I *don't* think that we need per-interface granularity, as the semantics
of an identifier should be host-specific, not identifier specific.
I hope that's right, but since you can't tell by looking at two IP
addresses if they refer to two interfaces on the same host, it's
unenforcable.
Brian
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