[Olsr-dev] Modification to the MPR selection algorithm

[Henning Rogge]

Am Mittwoch 09 Juni 2010, 21:52:57 schrieb Ayan Roy-Chowdhury:
> At present, we want to change the MPR selection algorithm only. The
> route selection will still be based on shortest path in terms of hop
> count. However, the local view of the network will consist of nodes with
> more stable links, and therefore, the shortest paths will be more stable.
> 
> > If you want to affect the route of the traffic, just forget about MPRs
> > and work on a better routing metric plugin. I would be happy to see
> > postprocessing for ETX that gives instable links a "penalty" and
> > stabilize the metric value with this.
> 
> Once we have the new MPR algorithm implemented, the next step will be
> to change the route selection algorithm to find the optimal routes based
> on most stable links (or some other metric). So we will run Dijkstra on
> the weighted graph. But this will be possible only after the MPR
> selection algorithm is changed.
The main problem with MPRs for linkcost based routing is that there is no 
datastructure to store multiple linkcosts from neighbor to two-hop-neighbor.

The 2-hop database is node-based, not interface based (a design problem for 
LQ-MPR). 

> Would it be possible to get the fix assuming it does the job, despite
> bugs? To compare the overhead between the default OLSR implementation,
> and the SPTC algorithm, it is necessary that TC redundancy is set to 0.
I will see what I can do... my first fix was just to 'complex' and it got 
worse, I will erase some code and try to start again.
 
> > I would advice to directly work on a routing metric plugin that outputs a
> > more stable metric value. That would be a GREAT contribution for future
> > OLSRd versions.
> 
> We are hoping that we will get to that point soon!
I'm looking forward to this.

Henning Rogge

-- 
1) You can't win.
2) You can't break even.
3) You can't leave the game.
— The Laws of Thermodynamics, summarized
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