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Wireless LANs Face Huge Scaling Challenges
BobB writes with this excerpt from NetworkWorld:
"Early WLANs focused on growing the number of access points to cover a given area. But today, many wireless administrators are focusing more attention on scaling capacity to address a surge in end users and the multimedia content they consume (this is particularly being seen at universities). Supporting this involves everything from rethinking DNS infrastructure to developing a deeper understanding of what access points can handle. And 802.11n is no silver bullet, warn those building big wireless networks. 'These scaling issues are becoming more and more apparent where lots of folks show up and you need to make things happen,' says the former IT director for a big Ivy League campus."
Sorry for the self reply, but I could find the whole paper here:
http://www.usenix.com/events/nsdi08/tech/full_papers/murty/murty_html/denseap.html
Erik Dalén
Not really, it all depends on the cable! I just had my house re-roofed, and up there in the eaves were a bunch of old cables and a plastic box marked 'Rediffusion':
http://rediffusion.info/cablestory.html
I think that system delivered about 5 tv channels, probably in black and white too. Nowadays I get 40 TV and radio channels over a terrestrial wireless broadcast system.
I don't recommend running cable to every place that you MIGHT need it. When I do remodeling, I run 'smurf tubing' down the wall in every room. It isn't really any more expensive than running 'just in case' wire. The benefit is that you don't have to worry about what kind of cable you might need in the future. I did this on my last house. When I remodeled each room, I put in a 2" tube from the attic to a face plate in the wall. I didn't pull a single wire until the place was done. After the house was done, I just fed the coax, phone and cat 5e cable to each of the places I needed it.
You're exactly right, very few people understand wireless. Heck, many people in IT probably don't understand the difference between a switch and a hub. An 802.11n wireless AP is essentially a 100 Mbps hub under IDEAL conditions since the hub doesn't really have to deal with signal strength, interference from other hubs.
I couldn't believe the article suggested that it would be a good idea to use 160 Mbps 2.4 GHz 802.11n. That would effectively cut your capacity down to half because you'd be using 40 MHz channels. We only have 60 MHz in the 2.4 GHz band total (80 MHz if we include the guard bands between the channels).
It's also weird that they would complain about 5 GHz not penetrating walls as easily. The whole beauty of 5 GHz is that you can't penetrate walls as easily so you can put an AP in every room and not have to worry about as much interference between the APs. The scalability issues go away if you do one AP per room. Heck, they use 24 802.11a access points on every possible channel on the trading floor of the NY stock exchange to maximize performance.