(Sorry; I have 3 topics in 1 email. Please feel free to split the thread
Paul Jakma [mailto:paul@xxxxxxxx] wrote:
> Aye. A lot of that detail would be lost in an AS-topology routed
> scheme; the disadvantage would be loss of IP-topology-scale traffic
> I'm not saying such a scheme would be the one to go for; I'm saying
> we may (or may not ;) ) one day have to face having to decide on
> trade-offs of "detail" Vs "scaleability", like the one in that
> scheme. ;)
I agree that we need more discussion on detail vs scale. I have a gut
feeling that they are naturally opposing features of a routing system.
Maybe somebody more expert than me (and more mathematically inclined)
can comment on this?
Now pragmatically: On average, for TE purposes, the normal Internet AS
needs something less granular than per-prefix attributes but more
granular than per-AS. Thus I would imagine that in an AS-topology routed
scheme each network operator would end up with multiple AS numbers,
where each was used as a TE equivalence-class identifier. This makes
"AS" a bit of a misnomer in such a system. :)
In the Internet today, "traffic engineering" is already quite imprecise.
For the most part, the tools available are side-effects ("hacks"?) of
explicit features. If we were to build TE as an explicit feature of the
routing system, what would that look like? For that matter, what TE
capabilities are required? I have my own list (below), but some
discussion around this would be valuable, I think.
Inter-AS/Global TE Features I'd like (non-exhaustive):
-control traffic proportions/balance across my available inter-network
-control whether and where I use multi-path for a given class of traffic
-direct certain classes of traffic to specific links
What other TE requirements are out there? (I know there are some, just
not at the tip of my fingers now.)
Idr mailing list