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 [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
