Hello, I know this mail comes a little bit early (metrics have not been merged into OLSRv2 draft), but I would like to like to argue for more than "include generic metric support in OLSRv2". Two weeks ago (just before the OLSR Interop 2009 in Vienna) I visited a conference about military communications. There were a couple of presentations which used OLSR as a mesh net protocol and they can be summarized as: "OLSR does not work well". When I tried to get some more facts about this I quickly recognized that all of them used hopcount metrics "because it's the default described in the RFC". I think this was a mistake in the OLSRv1 RFC, it described a protocol that did not work very well in the real world because of hopcount metrics. No amount of great research for new metric or improved features have changed this later, because most people USING OLSR for their research will use the stuff described in the default RFC. We should not do the same mistake in the OLSRv2 RFC. My suggestion is: include a simple version of ETX as an example metric into the OLSRv2 RFC. Why ETX ? Why not ETT/SNR/MIC/.... ? ETX is not the best metric out there, it's a very basic one. But it's VERY easy to describe and implement, it's independant from the layer 1/2 below OLSR and it allows to build much better real world networks than hopcount. I know no other metric that can provide these three advantages. We should add a few sentences into the chapter that this will be just the "lowest common metric" which should work with all OLSRv2 agents and that there are much better and more specialized metrics described in other documents and research papers. But if we do not put a real metric into the RFC we will have people saying "OLSRv2 does not work well" in years, just because they do their comparision based on the RFC implementation (hopcount). If there is a consensus on this I can easily write description of a simple Hello-Message based ETX implementation with a single tuning parameter for the draft. What do you think ? Henning Rogge
Attachment:
signature.asc
Description: This is a digitally signed message part.