On 3/4/08 3:13 AM, Jari Arkko allegedly wrote:
In any case, what I find interesting in this space is the different design tradeoffs. A routing system that hides multihoming and provider independence from the endpoints is easy for the endpoints and edge networks. I.e., you do not have to change hosts in any way, every network has a single prefix, renumbering is not necessary, providers/network owners are in control of what kind of multihoming and TE is going on, etc. But it also makes the routing system more expensive, because it has to maintain a lot of information. Many of the RRG people are searching for a better organization of this information so that its maintenance would be cheaper -- but you are actually looking at removing some of this information. I guess the main question is, can we substantially reduce the costs of the routing system while keeping the same amount of information and functionality in it? I'm not sure I know the answer yet.
The problem, as usual, is all the policy stuff, e.g. the various kinds of traffic engineering. I do not see that adding capability to endpoints will reduce what you have to do at the border router significantly. In Mark's approach the host uses multiple addresses intelligently but the border router still has to advertise reachability for them, manage what traffic takes which path, and so on.
Another drawback of the hiding approach is that it might be ultimately less capable, if you consider things like hosts being able to react on transport layer timescales to congestion and their own communication demands.
Could you be more specific? We have Mark's approach, with load balancing according to experienced throughput. The only thing routing could do to disrupt that would be to dramatically change routing frequently. Or are you thinking of "vertical coupling" approaches where something up at session layer can ask the network for changes in QoS, routing or virtual topology? Or ... ?
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