[Olsr-dev] loss_link_quality calculation

[Aaron Kaplan]

Hi Sven-Ola,


are you sure?
I did a simple calculation on paper yesterday and basically the LQs  
seem quite bad even on paper.
But maybe I misunderstood something. Can you explain a bit more?

Thanks,
aaron.


On May 30, 2007, at 9:42 AM, Sven-Ola Tuecke wrote:

> 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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