Re: IETF 57 Multu6 WG - Monday morning session - minutes

[Iljitsch van Beijnum <iljitsch@muada.com>]

On maandag, jul 14, 2003, at 19:02 Europe/Amsterdam, Geoff Huston wrote:

> - - draft-van-beijnum-multi6-isp-int-aggr-01.txt, Iljitsch van Beijnum,
>    15 min
>   Geographical aggregation. Admitted that topology is not correlated 
> to geography, and even if the geo part doesn't work there are still 
> some savings.

I did say a little more than that... I'll put the slides up at 
http://www.muada.com/ietf57-isp-int.pdf as soon as I'm online again 
(which should be around the time this message gets out). In the mean 
time:

- Goal is enabling multihoming ASAP. This is a short term solution.
- It works by distributing the global routing table over the routers 
within an (ISP) network rather than giving every router a full copy as 
is done today.
- This would lead to scenic routing but the geo aspect repairs this.
- Unless there is insufficient interconnection between networks, then 
aggregation must be broken.
- Geographic aggregates are internal to each network and not annouced 
externally.
- Correlation between topology and geography is less than 1, but also 
more than 0 and even without geography there are still some savings.
- No real downsides: RIRs must implement geographic address allocation, 
ISPs can implement this (or not) at their convenience.

> MH: This gives little actual aggregation
> ?: Asymmetrical routes break in your model
> IvB: Routing is asymmetrical in multi-homing in any case.
What I said was: today it's assymmetrical anyway (re hot potato 
routing) and when both sides do geo aggregation it is still 
assymmetrical, when one end is geo multihomed and the other isn't it's 
symmetrical. But read the draft as it has a section on exactly this 
issue from an ISP traffic distribution viewpoint.

> Tony Hain: Aggregatibility is the question. The concept appears fine, 
> but you are making assumptions about aggregation boundaries here.
Short answer: you can make your own boundaries or this can even work 
with your (Tony's) geographic addressing plan. Long answer: no time for 
the long answer...