Hi,
On Wed, 19 Oct 2005, Iljitsch van Beijnum wrote:
On 17-okt-2005, at 14:18, Jeroen Massar wrote:
Another alternative is to force-align allocation and topology in some
way /other/ than by "Providers" (geographical allocation in whatever
hierarchy, IX allocation, whatever), such that networks were easily
aggregatable. Lots of objections though (the "providers and geography
don't align" one though is ultimately slightly bogus, because with
non-provider-aligned allocation policies in place it would be in
providers interests to align their peering to match the allocation
policy).
Iljitsch, fix your attributions, that's my text. (Jeroen might not
appreciate you attributing my incoherent mumblings to him).
The current assumption is that all aggregation happens on ISP.
Replacing that with the assumption that all aggregation will happen
on geography isn't all that useful.
That's a bold assertion. You'll have to show why because the fact is
that that is how other networks achieve portability (after which
multi-homing is easy). Fact is I can change my fixed phone provider
and my mobile phone provider, but I can't change my ISP without some
pain (and I'm a /tiny/ site ;) ).
The important thing here is that you can aggregate on pretty much
anything: hair color, router vendor, market capitalization, you
name it.
Hmm, no ;).
In the end, you always aggregate on the way the addresses
are given out, which may or may not be meaningful.
No, you have to aggregate on topology.
Aggregating on provider is the most powerful because the aggregate
leads you fairly directly to the place where you need to go as long
as the destination is single homed.
Sure. But it means you're tied to the provider (for that address at
least).
interconnect within the city itself. So someone sitting in New York
probably won't see much difference: he or she still has to carry
all the routes for multihomers in Boston. Some of these will point
to her own customers in Boston, some to peers in New York, others
to peers in DC, and so on.
But at least, to the rest of the world, all the multihomers in Boston
and New York have reduced down to just 2 routes. That's a significant
step forward.
(And eventually those ISPs back-hauling lots of very specific Boston
customer prefixes to New York will figure out they should just peer
in Boston and confine the very specific Boston routes there).
limitations. An important one is that early exit routing is
replaced by late exit routing.
Can you expand on this?
Also, when someone multihomes by connecting to ISPs in Miami and
Tokyo you don't get to aggregate.
Or, that entity just gets two prefixes, one for its Miami site
allocated from the Miami area prefix and one for its Tokyo site
allocated from the Tokyo area prefix.
Really large networks with their own internal-transit across
multiple areas for whom this would not work can just get a global
prefix. But those kinds of networks are rare, a fraction of
multi-homers.
So it's still a step forward.
really sparse the savings go up again) so you're no worse off than
today.
You're better off, because small/medium sites can be aggregated with
all the other small/medium sites in their $AREA. The really large
trans-$AREA networks are rare.
Let's be honest, the reasons that make $AREA-allocated addresses and
aggregation difficult are /not/ technical. ;)
(Paul Jakma wrote something to the effect that I am involved with
shim6 so that says something about other options. It doesn't, as
far as I'm concerned. But shim6 is a worthy pursuit in its own
right.)
I said "possibly is telling" ;). But apologies for any presumption
;).
regards,
--
Paul Jakma [EMAIL PROTECTED] [EMAIL PROTECTED] Key ID: 64A2FF6A
Fortune:
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