[Olsr-dev] Thoughts about an ETX-FF-Metric plugin

[Henning Rogge]

Am Mittwoch 18 Juni 2008 20:33:32 schrieben Sie:
> Do you put any weight on the seconds in this window?
>
> how would this example be handled
>
> Second  : Received SEquence numbers
> 1: 1000
> 2: 1002, 1003
> 3: 1004,1005,1006
> 4:
> 5:
> 6: 1012
> 7: 1014,1015

> in second 2, i guess the LQ value would be 0.67
> in second 1 and 3 it would be 1
> but what about 4,5 are they put to 0 in second 6? or earlier? (after 1-2
> hello intervals)
> which value get second 6, 0.33 (2 of 3 lost), or 0.15 (2 of 6 lost) ?
No, I'm doing something else now...

There are two arrays (one called "received" and one called "lost") which 
remember the number of packets received/lost in a timeslice.

So your example would produce the array:

1: 1,0
2: 2,1
3: 3,0
4: 0,0  (maybe 0,1 if a hello timed out)
5: 0,0  (maybe 0,1 if a hello timed out)
6: 1,5
7: 2,1

The linkquality value is calculated by

LQ = sum (received[1..7]) / ( sum (received[1..7]) + sum (lost[1..7]) )

I discovered that if I calculate the LQ values for each timeslice, I get bad 
results because some slices don't have enough packages.

Henning


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