On Monday 20 September 2004 16:55, Jeff Gladnick wrote:
Well we are considering a wifi router (802.11g) for every other gondola cabin. So that would provide a large coverage area. I don't have a lot of personal experience with that, my impression is that it can only make 3 "hops" along a line. For Gondola lines stretching to 15,000 feet long, this could become a problem, especially in inclement weather.
Increasing spacing between the routers might help.
As far as I understand (but I'm not at all an expert in Wifi technology...), the 3-hops restriction *might* come from the fact that there can only be 3 independant networks coexisting (there are more channels, but most overlap). The trick then is to make sure that 1. Routers are close enough to each other that each router can comfortably "see" the next. 2. They are far enough that each can't see to hops ahead.
That way, the 3 hop restriction might be lifted... except for one detail: the line moving into the other direction will be too close, and in addition to seeing the previous and the next router, each router will also see up to 3 routers moving into the other direction. Not so good.
I also wonder how good Wifi technology is at preventing loops. Latency might be big enough that packets might run eternally in circles along the gondola line...
Hmm, I wonder whether it woldn't be feasible to somehow use the suspension/traction cable as a (low bandwidth) data transmission medium. Some clever hardware hacking would be needed to make this work (it's only one wire, and unshielded, so data transmission rate would be pretty low). Moreover, inside the station, the gondolas would be disconnected, but there again you can use Wifi (i.e. gondolas listen for transmissions on the cable when outside, and to transmissions of wifi when inside. Could be set up by equipping each PC with 2 interfaces configured to 2 addresses on a same LAN). A small codechange in udpreceiver would be needed in order to be able to join the multicast group on more than one interface.
So updating simultaneously can always be my goal, and updating once a day (if necessary) can always be the situation that I can live with.
Hooking up the upper station of the gondola may or may not be an issue. Usually these places are several thousand feet up in the mountains, in cold freaking weather. I am not sure if resorts have network connections up there or not. We will have to check into this.
Aren't there communication links anyways hooking the upper station to the valley station? After all, you probably have telephone and other amenities up there. And in most skying resorts I've been, they run electric wires on top of the support pillars (in the middle), in addition to the traction and suspension cables (on the sides).
It might even be feasible to setup Wifi access points on the poles, rather than inside the gondolas (which would remove the problems of access points moving around: in that case, only the receivers move, but not the APs). Potential problem: will they withstand the cold?
Alain