[Cerowrt-devel] cerowrt issues (3.10.24-8)

[Sebastian Moeller]

Hi Dave, hi list,

On Jan 30, 2014, at 17:21 , Dave Taht <dave.taht at gmail.com> wrote:

> On Wed, Jan 29, 2014 at 11:55 AM, Sebastian Moeller <moeller0 at gmx.de> wrote:
>> Hi Steve,
>> 
>> 
>> On Jan 29, 2014, at 19:24 , Steve Jenson <stevej at fruitless.org> wrote:
>> 
>>> On Wed, Jan 29, 2014 at 9:44 AM, Sebastian Moeller <moeller0 at gmx.de> wrote:
>>> On January 29, 2014 5:10:18 PM CET, Dave Taht <dave.taht at gmail.com> wrote:
>>>> On Wed, Jan 29, 2014 at 4:45 AM, Sebastian Moeller <moeller0 at gmx.de>
>>>> wrote:
>>>>> Hi Dave,
>>>>> 
>>>>> quick question, how does one turn of logging for babeld? It seems
>>>> that if daemonized it defaults to logging to /var/log/babeld.log (or
>>>> similar). Is setting the log file to /dev/null really the answer?
>>>> 
>>>> seems so.
>>> 
>>>      Okay, I guess I will try that then...
>>> 
>>> Here's the directive I'm using in /etc/babeld.conf
>>> 
>>> log-file /dev/null
>>> 
>>> and then you can restart either via the web gui or `/etc/rc.d/S70babeld restart`
>> 
>>        Ah, thanks. Since I am on 3.10.28-1 this was /etc/init.d/babeld restart. And I opted for putting:
>> option 'log-file' '/dev/null'
>> into /etc/config/babeld, since that seemed the more openwork way of doing things; I wonder whether it really is wise to carry both files...
> 
> 
> I stuck it in /etc/config/babeld.
> 
>>        Babeld runs again, and no /var/log/babeld.log appeared, but whether it works I do not know (and I doubt it given that babeld.log was growing due to nasty repeating error messages...)
> 
> It's working. It is just not making an optimal routing decision
> between AP-managed networks and meshy ones.

	Ah, if babel can work around this issue than there is no good reason to spam the log with repeats (at least not at the frequency it currently does, once per day might be more reasonable...)

> 
> The feature is called diversity routing, and it is key to making
> wireless networks scale better. There are (now), quite a few papers on
> it, but I like Juliusz's best...
> 
> http://www.pps.univ-paris-diderot.fr/~jch/software/babel/wbmv4.pdf

	Interesting, thanks for the pointer.

> 
> Notably this feature is also in batman, but it's called something else
> that I forget.
> 
> In an example with two radios on a cerowrt AP:
> 
> If you have a packet come in from channel 36, it's best that it goes
> out via ethernet if possible, channel 11 if not, and not channel 36.
> Even if the number of hops seems less, don't go back out 36, if at all
> possible, use a different route.
> 
> So right now babel is incorrectly distinquishing between the AP
> managed SSIDs (sw00, sw10, gw10, gw00),
> so the routing decisions there are sub-optimal.

	Is it really hard to get the radio and frequency for each interface from linux?

> As in most cases you
> are going to go out ethernet or one of
> the more meshy interfaces, or you have no choice but to send stuff
> along on one SSID... it's not very sub-optimal.

	Okay, that does not justify the log spam ;)


> 
> still, annoying. rule 22 in embedded design is "never write infinitely
> long files as the probability of running out of memory or flash always
> hits 100%"

	I agree (and then I would be happier if openwrt would have a preemptive mechanism to avoid this situation, be it log rotation and deletion or similar methods.)

Best Regards & mangy thanks for the explanation.
	Sebastian

> 
> 
> 
>> 
>> Best Regards
>>        Sebastian
>> 
>>> 
>> 
> 
> 
> 
> -- 
> Dave Täht
> 
> Fixing bufferbloat with cerowrt: http://www.teklibre.com/cerowrt/subscribe.html