Hi Robert,
> > It’s very clear that this is inadequate. > > Doesn't this really depend how you architect multiple levels ? Sure you have > some physical topology - but it seems to me that the trick is in properly > laying out levels on top of them and between them. The very pragmatic viewpoint is that network architects will construct the physical topology that best suits their traffic pattern and that trying to contort that physical topology into some kind of hierarchy will create additional (and perhaps significant) cost. People don’t want to do that. They want scalable networks that match their physical topology. For this to work, our hierarchical abstractions need to be independent of the topology and that forces us into having transit areas. > To my original question - how many levels can you run on the physical box ? > And can levels be locally and logically interconnected ? The constraint on a physical box is the amount of memory and CPU. Running 8 levels, each with 1000 LSPs per level is not out of the realm of doable within the next decade. Yes, levels can be logically interconnected through higher levels. I don’t understand what you mean by ‘locally interconnected’. > Then of course if you have applications (MPLS exact FEC match or SR-MPLS with > SRLBs) which do not allow any aggregation you are pretty much stuck no matter > what :). Broken architectures are everywhere. Folks that have solutions that do not allow for a hierarchical control plane are necessarily going to have issues. Hierarchy is the only tool that we have to fight scalability. Tony _______________________________________________ Lsr mailing list Lsr@ietf.org https://www.ietf.org/mailman/listinfo/lsr
