Re: [LAD] wfs streaming project report

Hi Joern,

On Sunday 18 January 2009 07:00:06 you wrote:
> nescivi wrote:
> > On Wednesday 14 January 2009 12:54:12 Jörn Nettingsmeier wrote:
> >> http://stackingdwarves.net/public_stuff/event_documentation/wfs_live_tra
> >>nsm ission_2008/WFS-Report-web.pdf
> >
> > wow!
> >
> > the paper did not mention this, but did you have any packet losses
> > through birds? or bird losses through packets?
>
> very rarely we did indeed have packet losses across the laser link, but
> since they were so few and far between (even in bad weather), i don't
> have reliable data. one possible weakness in the whole scheme is that
> the UDP redundancy methods of both jacktrip and netjack will send
> redundant packets right next to each other, so that if you have a burst
> failure (which is common), you are screwed.

ok.
Not so much a bird city, Cologne, I guess ;)
and not the trecking season... so probably there were not so many bird swarms
gathering to head south.

> for me, the morale is: lasers can be made reliable enough if you can
> tolerate the occasional single or short burst packet loss (loss rates of
> about 0.0001%), the general internet cannot, unless you get end-to-end
> QoS, but you can sneak past that if you have lots more bandwidth than
> you are going to need. but nothing in the world short of http streaming
> will protect your ass against crappy border gateways and switches that
> barf on udp stream traffic.
>
> as to bird losses, the class 3 lasers operated at 8mW, so the chance of
> a bird being vaporised is, ahem, slim.
>
> the main issue with respect to laser safety was eye damage. the minimum
> safe distance to look directly into the laser was about 50m. but since
> IR lasers do not trigger a lid-closing reflex (you only see a dim red
> shimmer), this minimum safe distance is determined for a duration of
> 100s of continuously staring into the lens (for lasers in the visible
> range, this duration is below 1s, iirc). so you would actually have to
> hover in front of the laser for well over a minute before your retina
> takes serious damage. therefore, we can safely rule out eye damage to
> birds as well, unless they are very skilled flyers, very bored and very
> very stupid.

What the visible range of birds? Maybe they could see the beam?
Just curious...

Thanks for the elaborate answer :)

sincerely,
Marije
_______________________________________________
Linux-audio-dev mailing list
Linux-audio-dev@lists.linuxaudio.org
http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
Received on Mon Jan 19 08:15:01 2009