[Olsr-users] OLSRv2_DLEP_CODE: User view - metrics calculation from oonf_layer2 db

[Henning Rogge]

On Mon, Nov 30, 2015 at 7:43 PM, s-mtafel <(spam-protected)> wrote:
> Hey Henning,
>
> thanks for coming back so quickly.
>
>> you will find one function where the oonf_layer2 API is called (hint:
>> search for "oonf_layer2_" in the file).
>>
>> This is the place where the DAT metric queries the layer2 database
>> about the incoming linkspeed... which could come directly from the
>> nl80211_listener or the dlep_router subsystem.
>>
>
> Well, I should have told you that I have already found this calc. I
> thoroughly greped for oonf_layer_ through the project. I just did not
> know about DAT, this part seemed too laconic for the full metric calc.
>
> Further, I have read the DAT RFC. But I do not fully get the interplay
> of the metric calc. and the delivered dlep_modem info.
>
> So far, the dlep_modem delivers interface specific radio data (at least
> the mandatory msg data items) to the dlep router part and that maps the
> received data into the oonf_layer2. Clearly readable in the oonf
> implementation. Fine:  OONF_LAYER2_NEIGH_RX_BITRATE is the focal point
> f. metric calc. as I unterstood. In ext_base/proto.c I can see the
> mapping betw. DLEP_CDRR_TLV and OONF_LAYER2_NEIGH_RX_BITRATE. Also the
> maping mechanism is obvious.

the "neighbor_probing" plugin also uses the "outgoing frame"
statistics... another possible user of DLEP.

> Ok. But the other dlep data items like latency or MDR are also mapped
> into the oonf_layer2 data base. What is about them. Are those completely
> ignored for metric determination? Do those not get melded into metrics
> in some way? Seems odd somehow.

The other stuff is interesting, but currently unused (expect to
display it with the layer2info plugin).

I did NOT write my DLEP implementation especially for the metric
calculation, I just exported as much interesting data of the Linux
Wifi stack as possible.

Henning Rogge