[Olsr-dev] LinkQualityMult support for olsrd development branch

[Henning Rogge]

Am Mittwoch 23 April 2008 15:25:44 schrieb David Murray:
> Hi Henning,
>
> Tried it again this afternoon, default routes seemed to work fine. I'm
> not sure why they were not working before. Also, the rewrite of ETX
> seemed to work fine with nodes running the old version (olsrd5.5). I
> only had time to test it out on 3 dual radio nodes this afternoon.
good :)

> I am still noticing that the rewrite of the ETX metric is giving
> different/higher costs. Do you know why this might be occurring? I
> would have thought that they should give the same cost if they are both
> based on [1].
No, the new ETX metric is using a moving exponential average to calculate the 
ETX value. (ETX = 1 / LinkQuality)

alpha = aging factor (default 0.1)

for every received Hello:
  New LQ = Old LQ * (1-alpha)  + alpha 
for every lost Hello (timer based):
  New LQ = Old LQ * (1-alpha)

This formula has a similar behaviour than the old one, but don't need a 
bitarray to store which hellos got lost. In addition to this new hellos have 
a higher weight than old ones.

> Tomorrow morning I will load it onto the other three nodes and let you
> know how I go.
I'm looking forward to it.

Henning


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