> >> It's been what, 1.5-2 years since then? We've already noted that HNCP looks >> awfully close to a link state protocol and duplicates quite a lot of of >> functionality. > > Right. It is essentially bit more modern take on a link state routing > protocol. So if you bring it up, I bring up the another argument - why not > route using it? Cost of doing _that_ is ~100 LoC (+ whatever fancy thing we > want to do with metrics). >
First of all, because there are differences between assigning a prefix and using it for routing. - Assigning a prefix does not mean you are the best router to route toward it. It may not even mean it is assigned to a link you are directly connected to. It may also be an excluded prefix. Assigning a prefix just means you reserve that prefix for some usage. One of this usage happens to be ‘prefix assignment to a link’, but it may be others. - There is a delay between the assignment and the actual use of a prefix. This is called ‘Apply Delay’ in the prefix assignment draft. I don’t think routing based on assigned prefix TLVs is a good idea because you would not try to handle assigned prefixes collisions correctly. Second point is that DNCP is going to transport multiple things. This will imply churn. As Gert said, I think protocols should do one thing and do it well. Babel is a loop-avoiding routing protocol. Do we want to put loop-avoidance mechanism in HNCP ? Of course not. Would HNCP be able to do routing ? Yes. But would it be able to do it if a buggy node constantly sends DNCP updates… It is less sure, and depends on the quality of the implementation. Last point is that the routing protocol we will agree on will not be the last we’ll ever come-up with. Some other will be invented. Better ones. DNCP is an element with a set of requirements. Let’s keep DNCP simple. A routing protocol has other requirements. And maybe some day we will decide to move to another routing protocol because we made a mistake or a new better routing protocol was designed. We need to make sure that this transition will be possible. And I think having an independent routing protocol running today will make this transition easier. Cheers, - Pierre _______________________________________________ homenet mailing list [email protected] https://www.ietf.org/mailman/listinfo/homenet
