On Mon, Jul 22, 2002 at 09:26:24PM -0500, Austad, Jay wrote: > As far as roaming goes, using public IP's isn't going to change the > functionality of that at all. Your border router routes for your public > address range, and your routers on the inside handle the individual routes > for each ip and tell the border router(s) how to get there. This can get > messy though depending on how many subscribers you have and what routing > protocol you use. You don't want to be flooding LSA's all over the network > everytime someone connects, disconnects, or switches to a new access point. > I think Richochet handled this by making all of their access points connect > to a central bridge so it was all one big broadcast domain. That way, they > didn't have to handle route propagation everytime someone switched to a > different AP. I can speak from personal experience here, very large broadcast domains like this do /not/ work well, our best bet would be sectors, roaming between those sectors would require either release/renew, MASQ/NAT, or mobile IP type setups. > > Plus, how viable is roaming with 802.11 or Canopy? GSM 1800/1900 has > special provisions for handling frequency shifts due to the doppler effect, > since many people talk on their phones while driving. Has the 802.11 spec > or Canopy been developed with mobile (as in driving) users in consideration? > While GSM has standard provisions for this, you will lose your signal when > the distance between you and a repeater is changing faster than 280km/hr. > While no one normally drives that fast, if wireless data protocols were not > designed with this in mind the speed at which you will lose your signal may > be considerably less. Roaming is a nice to have, but for the most part it's > probably not going to be a reality because you would literally have to > blanket the city with access points, the cost would be astronomical. Just > look at Ricochet, they did it, but then went bankrupt in the process. A lot > of that was their marketing department's fault, but their mistakes make a > nice lesson for others. In a flat, moderately 'green' area, I was able to drive from Mankato to Wilmar without losing connectivity except in a few dead spots. 60-70mph doesn't seem to cause any problems, of course, when you're going that fast, you shouldn't be playing with your wireless devices anyway =) The area in question had access points on water towers, grain elevators and various other 150-250 foot structures with an 8db omnidirecitonal antenna and directional antennas pointing at weak spots, or up/down a highway. Overall it works well, if you don't spend $1200 for breezecom radios that don't even support WEP. A little bit of frequency coordination, and a little clue go a long way. > Jay -- Matthew S. Hallacy FUBAR, LART, BOFH Certified http://www.poptix.net GPG public key 0x01938203