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Is There Too Much Enthusiasm Over Wireless?
lukOh asks: "in the US, 802.11b/g (2.4Ghz) devices use an
83Mhz-wide frequency range; in-use channels spanning 22Mhz and centered on one of 11 5Mhz steps (badly named as "channels"). This means there should be no more that 3 networks in close proximity, 5 'channels' far from each other, to avoid harmful interference. Now, in the middle of the mixed area where I am, the number of usable WLANs (SNR>20dBm) has gone from 10 to an unworkable number of 20, in just one month. Has the community/the market overestimated the practicality of wireless networks? Are we generally relying too much on such a young, IMHO immature technology made on 'startups hope' and broken firmwares? How can this mess possibly be handled in a working environment, especially the moment your boss asks you to give him access to 'the wireless'?"
"Access points can be easily detected, but the same isn't always true for every single client (or Bluetooth device) searching or using a network. Bluetooth itself employs the same 2.4Ghz range with 1Mhz-wide channels and much less power. To avoid interference a device jumps channel-to-channel, when the currently selected one is busy.
Most WLANs are managed by less-than-perfect SOHO access points. Connecting to an AP in such an environment is a gamble (even from 1ft away), especially when: WPA/WPA2 must be used; 802.11g stability is a dream; anywhere up to 7 networks are on the same 'channel' (1 and 11, being the most used, are standard on many devices); and now 'channel wars' are very common (i.e. 2 or more users concurrently hunting to set a free channel for their network, making the entire range unusable for hours)."
Most WLANs are managed by less-than-perfect SOHO access points. Connecting to an AP in such an environment is a gamble (even from 1ft away), especially when: WPA/WPA2 must be used; 802.11g stability is a dream; anywhere up to 7 networks are on the same 'channel' (1 and 11, being the most used, are standard on many devices); and now 'channel wars' are very common (i.e. 2 or more users concurrently hunting to set a free channel for their network, making the entire range unusable for hours)."
No one else is using it.
"Are we generally relying too much on such a young, IMHO immature technology made on 'startups hope' and broken firmwares? "
We're relying too much on an unregulated spectrum.
The extention of the 802.11b standard into 802.11g is a pain the arse for exactly this reason. All access-points should be limited to work on only channels 1,6 or 11, and rate limited so that anything too far away simply drops off, rather than throttling.
802.11a has a much better frequency spacing (8 non-overlapping channels in most juridstiction, 4 in the others), but many countries won't let you use it outside. The penetrating power at 5GHz is also less than at 2.4GHz.
Has wireless been overhyped? Hell yeah, but all we are seeing is the same problem that we all had when everybody went out and bought a 900Mhz cordless phone.
We need to either compress the channel bandwidth (OFDM with few channels around the center frequency), which would give less bandwidth per channel, extend the number of non-overlapping channels available. Jacking up the frequency would give better overall throughput and less channel conflict at the cost of range.
Norman Cook's Ode to Sl
Wireless technology is great.... when you absolutely need it. Take the Conference Room scenario, whats wrong with a high port density switch under the table, accessible via a central panel? You end up with a 'spiderweb' of Cat5 cables, but with wireless, you still end up with all the power cables.
Yes, its useful to avoid snaking a cable from your desk to your bed in your dorm room, but is it a necessity?
Or have consumers bought into the "I need my data everywhere" ideal promised by the wireless people (Centrino! Get it, you'll be a hipster Blue Man Group Guy) and the constant bombardment of high speed wireless access ads from the phone company (Verizon)?
Back in my day, we had vt100 and 9600 baud, and we ran long serial cables or keyboard extension cables if you needed to be able to compute while wandering around your dorm room or a lab. How much real progress has been made with the WWW and 802.11 ?
I want to delete my account but Slashdot doesn't allow it.
I have to troubleshoot a network timeout problem that doesn't happen in wired locations I support, but the wireless one times out when a certain application isn't used for about 10 minutes.
And the wireless printer there suddenly decided forget how to get an IP address from the wireless router.
It's not a happy time in Wirelessville.
Saskboy's blog is good. 9 out of 10 dentists agree.
If your device uses batteries then wireless makes more sense. If it's something that you don't ever want to replace batteries for, then you have to plug it in. At that point, you may as well plug it into the non-wireless network.
Wireless is a tool and can be great when applied appropriately. It is not the answer to everything as some would like to think.
I work for a college and once or twice a year someone brings forward the idea of a mobile cart of laptops for a roaming classroom. All laptops using wireless networking.
It sounds great until you find out they want to 30 students doing graphics or medical imaging at the same time. Of course we mention that it may not perform up to their expectations and that they should do some testing. They never follow through with the testing.
I'll say it again. Wireless is a tool and can be great when applied appropriately.
Keep the Classic Slashdot.
One Solution that /nerds seem to find suitable is to login to whatever access points are chocking your channels and change their settings.
I know, its not exactly ethical, it is legally dubious, etc.
But, since most people rarely change the default admin password, you can't argue with the results from switching people off your channel, or reducing the broadcast power of their WAP.
Mostly though, the issue is that WAPs aren't 'intelligent.' They aren't spread-spectrum, they can't automaticall channel hop because they can't predict how good/bad your reception will be... There's a whole host of technical challenges to making them play nicely together.
Here's a super nerdy pdf with equations, pics representing signal intensity/overlap. If it doesn't answer your questions in a highly technical matter, I don't know what will.
[Fuck Beta]
o0t!
I imagine we'll wind up with some sort of consolidation. We'll have something similar to phone companies with wireless. A regulated monopoly actually seems the most efficient here. I'd say the best example is radio stations. They are regulated so that they don't interfere with each other. We'll probably have wireless "markets" where different companies work. And at least here two or three could co-exist in some markets. And since competition among wireless providers means an area is more attractive to businesses, then gov't will maybe subsidize tower-building?
Others have described this as "The Tragedy of the Commons." Have a stretch of pasture where anyone can graze their cattle for free, and it'll soon be overgrazed. Have a stretch of the spectrum that anyone can freely use, and it'll become overused, so much so that no one gets any benefit.
I saw that in a town I visited where the water was unmetered. A local told me that at first it seemed a good idea. Water was so cheap and abundant, why go to the cost of metering and billing by usage? But unmetered led to waste and waste led to a search for new sources that turned out to be expensive. The result was that everyone, whether they wasted or not, had to paid sky-high water bills.
I hate to sound like a scold, but we need to make like good little hobbits and not trash our Technological Shire. We are going to have to discipline ourselves not to waste what's free. If wired can do the job with a trifling more effort (and probably less cost), we need use wire. Reserve wireless where it's necessary or particularly handy.
--Mike Perry, Untangling Tolkien
2. 802.11a does not use the same frequencies as b and g, and has more spectrum. Unfortunately, the wireless manufacturers aren't promoting it, but even if the complaint above - that there are only three distinct bands and therefore you can't have more than three networks in one place - was actually true, it is an actual solution.
3. The complaint noted by the article is false. While it is true that there are only three distinct, non-overlapping, slices of spectrum allocated for 802.11b and g, you can have more than one network using the same slice of spectrum, at the cost of efficiency and speed. It is not the case that having a network on, say, bands 1-4 suddenly means that no other networks can use that spectrum, either theoretically or practically. The more networks run on those bands, the poorer performance will be, that's all. In reality, the chances of the performance decrease being so bad that it actually makes more of a difference than your DSL's bandwidth is relatively low, especially in the US where 1.5Mbps is considered a really good connection.
So, to recap. Wireless works. It could be more efficient, but as sold, currently, it's more than up to the task. The proof of the pudding is that people are actually going out there and setting up their own wireless networks, and keeping them. We're not facing any real problems yet.
You are not alone. This is not normal. None of this is normal.
This does not work.
WiFi works on unlicensed spectrum, companies cannot claim it as their own... that spectrum is for all to use however they please within the limits set by the relevant agencies. Trying to bury the new guy by boosting your transmitter's output would most likely violate the peak radiation limit and get your transmitter shut down if not brought back within compliance.
What would be really useful is moving WiFi towards true spread-spectrum modulation to reduce performance degradation from multiple full and partial overlaps. The main issues with this would be extra complexity, longer channel scanning/sync times and yet more bandwidth (but at a lower mW/MHz density) per useful channel.
After a year of wireless I have just finished moving back to a wired home network. In retrospect it seems like a loony idea: why replace a reliable wired network with a whole bunch of expensive equipment that provided less performance with far less reliability?
Using your laptop on the couch or on the deck has great novelty value, but is useless from a work or ergonomic perspective. Throw in interference, inevitable drop outs, and the fact that real world performance is no where near the '54Mbs' marked on the box and it all adds up to an unappealing package in the home.
When I park somewhere to borrow Internet access, more often than not, the majority of WAPs are Linksys on channel 6. If it's a spot I might use again, sometimes I'll log in (l:admin p:password) and sort out the mess, putting some of the APs on 1 and 11.
I believe WAP manufacturers (the big three especially) have a responsibility to at least default each unit to a random channel (1, 6, or 11). Even better, have the WAP scan for and use the least cluttered channel on power-up.
Thank you, Edward Snowden.
"Arguments from authority are worthless." —Carl Sagan
But his Etch-A-Sketch is already wireless?
If they actually have a computer, simply connect his computer to the wireless router via CAT-5.
The paperless office will be wireless.
Dagnabbit!
Yessiree, when that paperless world finally happens, man, it will be wireless. I tell you, it will be wireless and we will all be on the beach...
Will the last person to press prt scr please toss out the printer.
I've been using wireless in the form of packet radio for almost 15 years and using aironet gear (the guys cisco bought) in production since 1998. While it's true that there are a lot of networks in the air most of them continue to function despite the interference. Isn't that strange??? no it's not ... all you need is a good enough piece of hardware to pick the sound from the noise. Perhaps more importantly I am writing this over a 5 meg full duplex wireless connection that gets fast internet to me from 13.2 miles away and hasn't dropped a packet in three years!!!
If there are 20 networks in range of you, why aren't they all doing the mesh thing to maximize bandwidth and get some redundancy too? This is just like with OSS - everybody wants to "homestead the frontier" instead of realizing that it's not a frontier anymore, and cooperate with what already exists. And those who are smart enough to do so want to secure the hell out of their networks too, not share with the neighbors at all. Just human nature, I guess.
The lack of organization is really inefficient. I'm surprised there aren't more organized free community networks nowadays; I really thought that was going to happen more, and that the big corporate empires wouldn't be as efficient about covering large areas with hotspots and then charging big fees to use them. A lot of hams have some sense of duty to use their skills for community service, but a lot of wifi hackers don't, apparently.
Dude, if you're gonna shoot, shoot. Don't talk.
Besides, nobody may understand what the hell you're talking about, but some will pretend they do, just to score some karma. Hell, you might even get a response that reads like it was lifted directly from a rejected fanfic script for ST:TNG!
Geordi: True, a 1-6-11 spread will maximize the spectrum with minimum nodular-crossinterference, but a triple-stepped 4 channel spread will remodularize the wifi matrix-
Riker (adjusting uniform): which would maximize headerless throughput and give us another 10 Teracycles on the core processes!
Picard: Make it so.
Troi: I'm feeling a sense of accomplishment here.
Chewbacca: Arrrr!