[Olsr-dev] loss_link_quality calculation

[Sven-Ola Tuecke]

Hi,

this is a hack from me. It basically changes the ETX route calculation 
window. Start with a small window, then grow to the original size. This 
grants a fast start. Otherwise ETX calculation needs the complete ETX window 
time to reach the "operation temperature" which is up to 10 minutes (in a 
standard config).

Your ETX probs may have another reason. Check for UDP loss, UDP-buffer size 
and generally use a lower Polltime.

HTH
// Sven-Ola

"Eric Lammerts" <(spam-protected)> schrieb im Newsbeitrag 
news:(spam-protected)
>
> Hi,
> can anybody tell me what the idea behind this loss_link_quality
> calculation in link_set.c is?
>
> entry->loss_link_quality =
>  (float)(entry->total_packets - entry->lost_packets) /
>  (float)(entry->loss_window_size < (2 * 4) ? entry->loss_window_size:
>  4 * ((entry->loss_window_size / 4 - 1) * entry->total_packets +
> entry->loss_window_size) / entry->loss_window_size);
>
> this was changed in CVS v1.65, it used to simply be:
>
> entry->loss_link_quality =
>   (float)(entry->total_packets - entry->lost_packets) /
>   (float)(entry->loss_window_size);
>
> The reason I ask is that I'm having some problems with olsrd 0.5.0. I
> have a network with some wireless nodes, and a few nodes that have both
> wireless and ethernet. On the ethernet I see ETX numbers like 17.19 and
> 3.29 (!!!), even though the ethernet has no packet loss at all.
>
> My config is:
>
> AllowNoInt yes
> DebugLevel 1
> IpVersion 4
> LinkQualityDijkstraLimit 0 9.0
> LinkQualityFishEye 0
> LinkQualityLevel 2
> LinkQualityWinSize 10
> MprCoverage 3
> Pollrate 0.1
> TcRedundancy 2
> UseHysteresis no
> Willingness 4
>
> Interface  "ath0" "eth0"
> {
>        Ip4Broadcast       255.255.255.255
>        HelloInterval      6.0
>        HelloValidityTime  90.0
>        TcInterval         3.0
>        TcValidityTime     300.0
>        MidInterval        15.0
>        MidValidityTime    300.0
>        HnaInterval        15.0
>        HnaValidityTime    90.0
> }
>
> I always run the same olsrd and the same parameters on all nodes.
>
> I know I have FishEye off, but my network is currently pretty small (<= 3
> hops max) so I don't think that should matter.
>
> I changed the calculation back to the old one, and now the ETX on all my
> ethernet links is 1.00. The network is also much more stable on the
> wireless connections.
>
> thanx
>
> Eric
>
>


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