Re: [v6ops] [GROW] Deaggregation data (was: Deaggregation by large organizations)

Hello Nick and Iljitsch,

fairly stable baseline of 20-30%, which may be acceptable if it stays there. 
Although peaks of 70% (is the 100% a graph problem?) seem to be a reason 
_for_ filtering.

Now what I'm wondering

(1) is there a need to carry all the deaggregates? Because if you are far 
enough away they may "look the same as the aggregate". To use Iljitsch' 
example ...

> I know this is controversial. "Topology ain't geography". Actually, most of 
> the time there is a significant correlation. If all German cities inject a 
> more specific, do you really need to hear those in Tokyo or Seattle? Just 
> send the traffic to Europe as per the aggregate and let them figure it out 
> there.

... it's likely that for an US ISP X, peering with European ISPs Y and Z who 
carry the various deaggregate plus aggregate from Germany, all the European 
prefixes have this peering router as next hop (let's say we have 
next-hop-self).

What about BGP on this peering router doing some auto-aggregation in such a 
case?  Has this been discussed?  It would avoid geographic communities and 
would simply follow the BGP topology: if the deaggregates result in the same 
forwarding information than the aggregate just keep the aggregate. Your 
routing table would have deaggregates for your own region but only aggregates 
for the other, more distant regions.

(2) the problem of ever-growing routing tables and de-aggregation is not new. 
After so many years I'm wondering if the answer is that this cannot be solved 
with BGP/routing alone (?)  Otherwise you would have found a solution 
meanwhile :-)
And we have the - understandable and growing - needs of Enterprises, who 
de-aggregate their PA addresses when they are LIR, or request PI addresses 
per location.

Combining this, should the de-aggregation step not be done with a different 
technology? LISP comes to my mind (biased, as I'm working on it) or in 
general a "de-aggregation overlay". The overlay would need gateways to the 
BGP world and would announce one aggregate prefix only while the de-aggregate 
prefixes would be limited to the particular Enterprise overlay network and 
would not show up in BGP.

Regards, Marc

On Thu, 16 Oct 2014 22:16:09 +0100, Nick Hilliard wrote:
> On 16/10/2014 16:47, Iljitsch van Beijnum wrote:
>> Growth in IPv6 more specifics was 57% last year...
> 
> Here's a graph which shows the percentage of more-specifics between 2003
> and today from Geoff Huston's web site:
> 
> http://goo.gl/QA0xud
> 
> Eyeballing the graph, it's not clear where the figure of 57% came from.  In
> terms of trajectories, there doesn't seem to be a major problem either.
> 
> Nick
> 
> _______________________________________________
> v6ops mailing list
> v6ops@ietf.org
> https://www.ietf.org/mailman/listinfo/v6ops
> 