802.11 vs. 3G For Mobile Access 99
bobdole34 writes: "A new way to give us fast mobile net access spells further trouble for 3G.Imagine being able to surf the net at speeds faster than DSL from anywhere, at any time - you could watch a live video webcast while waiting for the bus, email photos to your friends while sitting in the park, or download the MP3 of the song that's playing in the pub before it finishes. I smelled vapour until I saw a demo of MeshNetworks at 802.11Planet in Philly."
Two Towers (Score:2)
Or you could download the Two Towers [slashdot.org] before any of the Dialup or DSL bastards can get their hands on it.
Your palmpilot gets a fatter pipe than my desktop.
I hate you.
I feel your pain (Score:2)
the problem and it's a huge problem that mesh works only when you have enough people
much like haveing enough people to become econmic to install a 802.11 in a cafe
also it becomes a divide between people that have and have not i.e. those in sparsly populated areas where they wont put an arial because they dont have enough people
there are so many reasons why this will fail
there are lots of Real case studys where this type of thing failed
so vapour it's truly amazing
regards
John Jones
p.s. so tell me why this isnt just 802.11g
You can't believe everything you see in demos (Score:2, Insightful)
sheesh, I saw tons of cool demos at linuxworlds in the past and nothing came of them!
It could help (Score:1)
Re:It could help (Score:2)
Re:You can't believe everything you see in demos (Score:2)
When this takes off, I expect it will be the newer optical mesh stuff. Since they can deliver much more bandwidth than the microwave system, it can scale much better. Curren wireless mesh systems seem to be able to deliver slightly better than cable systems or ADSL with a high oversubscription rate.
One major problem with all the wireless systems is that there just aren't enough bits allocated to go around if any of this stuff gets popular.
Holy Crap! (Score:2, Funny)
Not only is it so fast, but it runs over conventional 802.11b. I hope this becomes widespread enough so I can get it up here in the middle of nowhere North Dakota.
The question is with wireless internet getting this fast I wonder if we'll start to see outdoor LAN parties???
Re:Holy Crap! (Score:1)
Re:Holy Crap! (Score:2)
Where's the bandwidth going to come from (Score:5, Interesting)
Wireless networking occupies a relatively narrow band of the frequency spectrum, and probably less than the 3G ranges offered to telcos.
I highly doubt that an 802.11 mesh will ever provide that much bandwidth - especially once things start relaying in many directions at once.
Imagine splitting it up into cells, each one where a user is. As something transmits from one cell to the next, it'll use bandwidth (or available frequency space) in the neighbouring cells.
Anyway this could work for dense areas but screws over the people living in the country - worse still, it's not dependable. What if you need to make an emergency call and nobody is within range?
I heard nokia were wokring on a hybrid tech that allows you to use mesh networks when they are around and 3G otherwise - that would be cool
Also i could raise the usual problems of accounting for bandwidth use on this kind of net - who pays for it all?
Re:Where's the bandwidth going to come from (Score:2, Insightful)
My question is what happens when everyone leaves downtown at night? Since there is no one to relay the signal, you'll only have coverage when you are close to an AP
Re:Where's the bandwidth going to come from (Score:1)
Of course, this number drops precipitiously on a P2P network.
If the guy you're sitting next to at the coffeeshop has today's copy of the NYTimes cached on his laptop, why contact NYTimes.com?
Re:Where's the bandwidth going to come from (Score:5, Interesting)
Also, we already have a 22Mbps variant of the 11Mbps 802.11b standard, and the 55Mbps (or thereabouts) 802.11g standard is in the works. There's no reason why the mesh network APs couldn't start with at least 22Mbps radios. Even with real throughput at a bit over half the stated amount, that's enough to start.
Plenty! Re:Where's the bandwidth going to come (Score:4, Interesting)
Ok, first you gotta realise that 802.11b (even) by access standards is fast!
With a contention ratio of 50, and giving each user 576K you get:
11,000,000 / 576000 * 50 = 954 users
That's on a single connection, within say 100m of some user.
So even 11b can allow enormous numbers of people 'broadband' capabilities.
Secondly, that's with current technology only- a more advanced technology would allow multiple networks on the same frequency by using directional aerials- this can multiply up the usage maybe 20 times. Then there's the fact that even 11b allows atleast 3 different channels (in practice). We're talking thousands of people, potentially,in little old 1b land alone.
Anyway this could work for dense areas but screws over the people living in the country - worse still, it's not dependable.
Yes, this is the issue. WiFi is basically line of sight, or 100m range. However that's a regulatory issue, mostly. The only reason that WiFi is so restricted is due to power limits. If the users were allowed to shout louder, they would be able to go further, and then country people would be in range of each other anyway (chances are).
What if you need to make an emergency call and nobody is within range?
Cell phone? Who says WiFi is for emergency calls anyway?
Re:Plenty! Re:Where's the bandwidth going to come (Score:2)
I see - so do i mount the directional antenna on my head and make sure i always look north?
Re:Plenty! Re:Where's the bandwidth going to come (Score:2)
If you want to! You'll look silly, and it won't help, but you can if you want to ;-)
Hint: directional antennas can be multiple fixed antennas that are electrically switched to form a 'phased array'. Similar to what the military use for their radar systems on aircraft.
Re:Plenty! Re:Where's the bandwidth going to come (Score:2, Insightful)
Your first mistake is assuming that the quoted 11Mbs is the actual data-throughput. It isn't, because of the protocol overhead you lose 50% of the quoted bandwidth straight away. As the bandwidth is split into discrete amounts depending on your reception, you actually get 500kb,1Mb,1.5 Mb or 5.5Mb and unfortunately you really need to be in ideal line-of-sight for 5.5Mb.
Secondly, you assume that these huge numbers of people are all within range, of what? There are no good scalable peer-to-peer routing algorithms for mobile networks. The best ones in the literature all use a form of random flood filling of the network so on a city sized scale that's going to break badly. If you have base-stations everywhere then you need almost as much infrastructure as a 3G network. Add to that the really bad urban-canyoning and reflection problems and you end needing a basestation in nearly *every* starbucks
We're actually in the process of rolling out a free 802.11 network over Bristol. Even though the project is funded the hassles of sorting out planning permission for aerials and putting in backbone means that after a year we've only just starting rolling with 3 aerials installed over a tourist area so that we can start doing demos.
Don't get me started on the other 802.11 limitations, it was designed for sitting browsing the web in the back-garden. It has latency and broadcast issues that make it unsuitable for streaming real-time video and audio, bad routing, IP hand-over issues and a pile of problems. People just look at the raw bandwidth figure and start creaming themselves over 55Mb bandwidth appearing everywhere but unfortunately the inherent problems with 802.11 mean that it isn't really as good as it sounds.
Re:And It's Goes A Little Something Like This... (Score:3, Interesting)
1. The Telcos start whining to their regulators that they are being deprived of revenue, as point-to-point trunk calls lessen for 802-based communications.
2. The wireless carriers (who still haven't found a stable, profitable business model -- i thought PacBell Wireless was bad -- until Cingular bought 'em) will join in with the trunk owners and scream that their FCC franchise is being devalued by Wireless IP Data and IP Telephony and they need government help (read: R-E-G-U-L-A-T-I-O-N) right now.
3. The Consumer Giants will whine and bitch and snivel about interference issues with 2.5 and 5 GHZ devices they make.
4. The law enforcement/intelligence community will endlessly bitch about their lack of ability to "monitor" this dangerous new technology, and how this creates a national security vulnerablity and therefore, offers a "window of opportunity" to evil-dewars. They will insist on lousy/key crypto and 1.5 bit key algorithms, and their ability to "oversee" the security of this spectrum.
4. The G, sensing the increased value of this spectrum and their ability to make even more money in licence fees and regulatory overhead will further regulate the spectrum and cause more and more expense to be made to justify their jobs and administration and regulation of it.
no wonder i don't sleep much.....
Re:And It's Goes A Little Something Like This... (Score:1)
Re:And It's Goes A Little Something Like This... (Score:2, Interesting)
Having looked over and drooled over some of the latest, greatest wireless offerings such as ATT's "mlife", I got to the point where I read exactly how much they charge for the service. They are kidding with these pound-me-in-the-ass prices for data, aren't they?
Here is a great technology just waiting to be used, and they brag bout downloadable games and video and music and they best they can manage is $12.50 for 2MB of data per month? Isn't all the data coming from/going to the phone digital data anyway? At least it's cheaper (and better) than the Palm VII's Palm.net service and that was cool in its day was well.
The more power to the people who start these mesh networks, the better. Prices need a little bit more downward pressure.
Re:And It's Goes A Little Something Like This... (Score:2, Funny)
Do you expect anyone in a huge company, who mostly uses the Internet for porn and ebay to understand why anyone would want to plug in a laptop? Verizon gets close. AT&T wants us to turn Japanese, Nextel wants us to be truckers, and Singlular... as far as I can tell, Singlular wants us to be gay.
Re:And It's Goes A Little Something Like This... (Score:2)
I expect smaller mom and pop wireless ISPs will lead the big players to the fount of wisdom by example, and the ones that drink from it will prosper. This is just like the first ISP boom all over again - a lot of smaller actors get on stage and fight it out and then the big ones eat the surviving small ones with viable business models, paying customers and cool buzzwords.
cool (Score:1)
I'll be the first person on the bus using this technology!
Thanks Slashdot!
Re:Napster gets pulled at last?... (Score:1)
Battery Use (Score:2, Interesting)
Re:Battery Use (Score:2)
Also, isn't the onus on device manufacturers to manufacture a wireless chip/card/ that uses power intelligently? Eg. when only transmitting pings / packets to maintain your ip on the "mesh", use minimal power?
That begets the idea: the majority of users might not even need to be connected all the time. Then a simple powering down of the wireless chip/card would suffice once no network traffic is scheduled.
Little savings here and there can go a long way.
Re:Battery Use (Score:1)
that would be impossible since that case should never happen.
Imagine what the coverage would be at night when most of the users don't use their devices.
As is said in the article, every user that connects improves the coverage, but any user that disconnects worsens it
add to this that majors and movie studio will go crazy after reading the article and might well be the first to buy the technology to burry it ASAP
Add to this that routing/relaying DOES use bandwidth so probably you will never see the announced 6Mps or 400Mbps, as i understand it what u will get is 6Mbps shared badwidth and though that is more than enough for a lot of users just using email and browsing the web, file transfers require a lot more than this.
Re:Battery Use (Score:1)
Crypto (Score:2)
Before this tech. gets too far, it will have to deal with the whole "wireless security issue"... which is quite a beast.
Of course, tunnelling traffic through a proxy of some kind (VPN-style) could help matters, but it will of course affect speed.
-jbn
You mean I might actually get something for my $? (Score:2, Interesting)
There is no billion dollar market for wireless web services, and their won't be until it is cheap and easy to use. I.e., years from now, possibly longer.
Re:You mean I might actually get something for my (Score:1)
Battery life is not such a big deal with laptops, but with cell phones it's different. With my phone I notice that the battery goes much faster when I'm in analog areas, even if I'm not making calls. I can just imagine it trying to constantly relay 802.11 packets!
Funny memory... (Score:2, Funny)
Granted she wasn't really a fountain of networking knowledge and I proved her wrong on a daily basis, but it's nice to see how wrong she can be.
Re:Funny memory... (Score:1)
Re:Funny memory... (Score:3, Informative)
This 802.11 solution would not be a fully meshed network but, rather a series of partially meshed networks which would make them smaller and more manageable. Furthermore, these networks would have the ability to develop new interconnections automatically and dynamically so the management aspect would not be an issue. Also, due to the use of wireless for these connections, rather than physical connections used by point-to-point and frame-relay, cost would not be nearly as big an issue.
In other words, your teacher was correct but, those rules do not apply in this scenario.
Contradictory (Score:3, Informative)
Re:Contradictory (Score:2)
802.11b is used by the people. I have a card. It rocks. It won't die until my card breaks, hopefully not for a few years yet... and I'll probably buy another one when it does.
It's great being able to sit in the garden and surf
Step up from vaporware... (Score:4, Funny)
Yes yes. What you saw was a step up from vaporware, commonly referred to as a "dog and pony show".
Fundamental difference is... (Score:5, Interesting)
Think about it. You plug a wifi card into your laptop and start surfing. Battery life cuts from 4 hours to 2.
This study [synack.net] examines current 802.11a solutions... chances are there will be some improvements, but it averages 100 microwatts/sec regardless of whether it's in use or not.
OTOH, 3G phones [adelantetech.com] (with their tiny ickle bodies and tiny ickle batteries) consume power at 25 microwatts in TX/RX, and only 1 in idle mode.
This article [eetimes.com] talks about how 3G power is a challenge for handset manufacturers even now, designing for 3G. You think your phone is gonna be able to cope with 802.11a? You're wrong.
3G and WiFi are both cool. But they are different.
Offing of the turning of the (Score:1)
Re:Offing of the turning of the (Score:2)
Maybe a low power setting would work, though.
Re:Fundamental difference is... (Score:2)
Nah. I haven't seen any degradation of battery life at all.
but it averages 100 microwatts/sec regardless of whether it's in use or not.
Ok ;-) My laptop powersupply is in rated at 48 watts, who cares about a few hundred microwatts? The phone issue is very different, batteries are much smaller in a phone. My laptop battery is about the same size or bigger than a cell phone ;-)
What you say makes good sense for a cell phone though.
Re:Fundamental difference is... (Score:2, Interesting)
Looks like your numbers are off, though.
Re:Fundamental difference is... (Score:1)
Open the specs (Score:2, Insightful)
Didn't think so. They are looking to boost stock value in an effort to capitalize on an eventual takeover.
If they did this for the good of mankind, they would have made the code open source.
What we need is a software-reconfigurable wireless lan card that could be programmed to communicate as needed...
Re:Open the specs (Score:1)
Re:Open the specs (Score:1)
Damn, there is a difference, you know?
They are selling a Hardware System. All I want is the spec to the hardware to be completely open. It's not like I can click the copy button and get a bunch of network cards to spit out of my PC.
I want the specs to the card to be open so it can be used even though the company might be bought/go out of business.
Besides, I like to get paid, so I understand your point exactly.
Re:Open the specs (Score:1)
Some GPL'ed implementations and other links (Score:3, Informative)
Also, is a collection of links on mobile routing protocols [nus.edu.sg], and mesh routing protocols that were originally designed for wired backbone links [pacific.net.au].
The big difference... (Score:2)
Mesh networks are still a dream. High speed mobile internet is here now [verizonwireless.com]. At $99/month, it's not quite worth it yet though, especially because you agree not to use it for your home network.
Anyone want to help me set up a WiFi network in Pitman, NJ [yahoo.com]? Somehow I doubt it.
It ain't that simple (Score:2, Interesting)
Much more important is that in practical terms, the bandwidth of the airside isn't the limiting factor in a public-access network. In an office environment, you can get something like 3.4-4Mbit/s out of 802.11b (depending on your adapter, and on whether you are using WEP encryption). In a public-access network, you've got to pipe that down some back-haul pipe to an upstream PoP. Either you use cheap-and-cheerful 2Mbit/s DSL, and put up with contention at the DSLAM, or you pay for something like a T1/E1 with dedicated bandwidth. Even if you pay for the dedicated bandwidth, you're probably going to end up with at most 2Mbit/s shared between your active customers.
You'll have to check prices yourself, but it's difficult to see how you can make a profit unless you dimension the system for a fairly low target bandwidth, say 256kbit/s, when you cost in the bandwidth and the installation labour. That makes it much closer to 3G in practical terms - probably a bit faster and a bit cheaper, but with access restricted to hot-spots.
Why the profit motive? (Score:1)
Sounds to unreliable to me. (Score:1)
OK, I can understand a system where they mount fixed accesspoints all over the city and the accesspoints relay traffic to their neighbours over the air instead of beeing connected thru cabling.
But relying on the mobile-devices themselves sounds to error prone, I wouldn't want to be at the edge of the coverage area where I see only a few neighbours, what if they decide to turn of their phones or just move out of range.
Re:Sounds to unreliable to me. (Score:2)
Yay! Streaming broadband pr0n on the bus! (Score:2, Funny)
This has the potential to transform human society in ways we cannot even anticipate!
Imagine millions of commuters all watching Pam and Tommy Lee do their thing on the way to work in the morning! EVERY morning! My friends, we stand at the gateway to a new and better way of life for all human organisms on this ever-shrinking little old globe of ours.
The malevolent forces of evil, tyranny, poverty, stupidity, Scientology, lambda calculus, feminism, fascism, organized religion, the ASPCA, and Wizard of Oz/Pink Floyd theories will wither away like ice in a spring thaw!. THE CORPSES OF THE INIQUITOUS WILL LITTER THE STREETS! Wild dogs will gnaw the dry bones of the unrighteous! Everybody will have an above-average income and nobody will have to stay home on prom night!
Fuck a duck, man, this is heavy shit.
it is not 802.11 vs. 3G, it is 802.11 AND 3G (Score:4, Informative)
this clip is from Business 2.0:
<clip> Ultimately, however, 3G and Wi-Fi should be able to coexist. "The technology is actually very complimentary, because they are not truly competitive technologies," King says. "I expect that mobile carriers will purchase some Wi-Fi providers, and we'll start to see some integration." </clip>
Re:it is not 802.11 vs. 3G, it is 802.11 AND 3G (Score:1)
Plus the WLAN supports a SIM card which allows operators to provide secure chargable WLAN services in public spaces.
More info here on Operator WLAN [nokia.com].
You know what I do with my wireless connection? (Score:1)
WEP - The only major obsticle (Score:1)
Re:WEP - The only major obsticle (Score:2)
If it isn't encrypted, those communications are subject to eavesdropping. No law, not even the death penalty is going to protect a person from a breach of privacy. Only strong physical security is our friend.
hmm... faster than DSL by who's standards? (Score:2)
Yahoo BB in Japan has DSL for 12Mbit downstream.
for 30 bux nontheless.
thought that's something people in the US could find interesting to drool on...
p.s. last i checked, 802.11 speeds drops off drastically when
* distance between nodes gets far
* many people sharing freq. spectrum
and 3G is nowhere NEAR the m-bit speeds on an individual basis.
so yeah... sticking w/ DSL for all my pr0n needs.
The main problem wtih 802.11b (Score:2)
It's in an ISM band.
So... there is no guaranteet that once your company has rolled out it's 802.11b infrastructure city wide, that something else can't interfere with it. They don't hold a license for the spectrum. My cordless phone can smash it, and they can't do anything about it. Other can set it up as well.
MP3s? (Score:1)
Now the RIAA is gonna make sure this technology never becomes mainstream....
Apples vs. Oranges? (Score:4, Interesting)
I could imagine that, except I can't get DSL out here, and likely won't be able to at least until the end of the decade. I'm assuming you mean by very limited definitions of "anywhere." More like "anywhere you would care to be."
"you could watch a live video webcast while waiting for the bus,"
"Bus" = "Public transport" = "population density" = "not me."
"email photos to your friends while sitting in the park,"
"Park?" Another one of those things that suggests population density. See, out here we have these things called "back yards"...
"I smelled vapour until I saw a demo of MeshNetworks at 802.11Planet in Philly."
802.11 is a wireless LAN technology. Do I need to remind you what the "L" in "LAN" stands for? Rigging up local transceivers for a single building is a heck of a lot simpler (and cheaper) than an entire city. And that's only for you folks that live in cities (read "for those of you that matter" as far as just about everybody seems to be concerned, even on here).
On the other hand, 3G is essentially a WAN technology, with its much wider tranceiving radius. It may be a cold day in Hell before BellSouth gets off their good-for-nothing behinds to upgrade the local switches for DSL (let alone somebody setting up 802.11 WAPs every few hundred feet along US 90... not that I live close enough to 90 to begin with...), I at least have some access to Sprint's network out here.
I'm sorry, but trying to say that 802.11 can and will compete with G3 is like saying that Gigabit Ethernet is going to edge out the T-3 market.
Oh, and before somebody brings up how Canada has DSL "everywhere" with their larger land mass and smaller population, ever wonder why the United States [cia.gov] seems to have twice as many meters of paved highways per person than Canada [cia.gov]? Maybe because the Canadian population isn't as dispersed as the American population?
Re:Apples vs. Oranges? (Score:1)
Well, if you connect up a few of these [fiberdriver.com] to your GBIC ports, yes, it does replace T-3.
Re:Apples vs. Oranges? (Score:2)
More dispersed, less dispersed: your argument might hold water if U.S. DSL service weren't horrid everywhere. Look at the "National ISPs/Telco ADSL" section of [dslreports.com]'s reviews. Bell Canada is the cheapest provider there (even ignoring the exchange rate!) and has the shortest wait time by far. Excluded from that list are all the non-Bell providers who offer equivalent service for even less.
Are you seriously claiming that "outback" regions like California, New Jersey, or New York state are less densely-populated than the whole of Canada?
Re:Apples vs. Oranges? (Score:2)
Then how about this one: There are more telephone lines per person in the United States than Canada. We're not just talking about more hardware needing upgrading and replacement, we're also talking about more hardware per person.
"Are you seriously claiming that "outback" regions like California, New Jersey, or New York state are less densely-populated than the whole of Canada?"
Ever been to Fresno or Sacramento in California? Camden or Trenton, New Jersey? What about Ithica or Albany? It's amazing how the countryside changes as soon as you get away from the major population centers. People are left wondering why New Jersey is referred to as "The Garden State" when they've never been off the New Jersey Turnpike, but the majority of the three states you rattled off are farmland or even wilderness.
The presence of Chicago doesn't make the rest of Illinois magicly look different from Indiana just as the presence of Calgary doesn't make the rest of Alberta look different from Saskatchewan. Of course, I'd be willing to bet that more people live in rural Illinois than rural Alberta.
Re:Apples vs. Oranges? (Score:2)
I pointed out that even in remote regions, our service is superior to the densest parts of the U.S. Number of roads, phones, planes, or Jesus stickers per resident doesn't change that.
Addressing the dispersal question, though:
CIA factbook says 85% of Canada's population lives within 300km of the U.S. border, whose length (excluding the Alaskan border) is 6416km. So to bolster the OP's claim, we'll exclude the 4/5ths of Canada that isn't in that strip -- i.e., all except the most dense part. That gives us a population of ~27million in ~2million km^2: 13.5 residents per km^2.
Now compare to the U.S.: Just for fun, we'll ignore the populations of NYC (16.6M) and LA (13.1M) since these mega-cities skew the density upward just as Canada's great white north skews it downward.
The result? ~248M people in a little under 10M km^2 or 24.8 residents per; double that of Canada's most dense region.
RE: 802.11a = Too Much Power (Score:1)
Two more jumps like this (.10u and then
I too used to say 802.11 will never go into hand-help applications (Cell phones & PDAs) but I am starting to rethink that position,
Re: 802.11a = Too Much Power (Score:2, Insightful)
do this ourselves (Score:1)
We could do this ourselves. As a publicity stunt, why not try to connect a computer in NYC to one in Los Angeles (or the Bay Area?) via 802.11b connected computers (on the ground). It'd be interesting to see how you can get the connection across the desert, but still the cost would be minimal for all those involved.
Also, about this mesh thing: it won't work late at night when everyone except me is asleep.
Tradeoffs (Score:2)
Early bluetooth (Score:1)
802.x WAN will never get serious (Score:2, Insightful)
Anyone with experience in WAN coverage for Motient/Mobitex/RAM/ARDIS/Cingular/CDPD (whatever those groups are calling themselves this week) realizes that COVERAGE is KEY.
A convention center trade show painted with WiFi is not greater NYC. Just because you can surf the web with your laptop while on the second floor toilet in your house it does not mean you can scale outside your teeny D-Link range.
Let me guess - people will actually care to use a patchwork system that will have gaping holes every 1000ft or so. Yeah, sounds like a real world enterprise solution to me.
Get it straight - WiFi in the warehouse - WAN everywhere else (except the desolate Dakotas....).
mesh technology (Score:3, Informative)
They are a byproduct of military-funded tactical
radio R&D. There is an emphasis onself-organizing topology and route discovery. If every soldier and vehicle is lugging a radio, then the network
has a good chance of continuing to operate even if parts of it are destroyed.
This kind of mesh does have some pathology.Take some number, say 10, of nodes placed in a straight
line. You are at one end of the line and the internet ISP is at the other end. And you have
10 wireless hops between you and the internet. And the people in the middle of the line may not be really happy with you either.
There are non-proprietary approches. Check out the ietf MANET working group at
http://www.ietf.org.html.charters/manet-chart
There are numerous university projects. Try Google(mesh network & university)
or Google(mobile network & university).
There have been numerous failed startup company attempts at mesh networks. One approach that I found very appealing used a self-organizing mesh
that organized itself into rooted tree structures.
The internal tree branches served as backhaul connections to the internet. The leaves represent the clients/users. The internal nodes are not mobile. They are devices to be installed on utility poles or public access locations. They find one another and create an uplink/downlink
infrastructure where uplink means a path to the ISP or other wired infrastructure and downlink
means to the client. I liked this approach because it builds a predictible structure that
can be analyzed and because the routing procedures
within the internal nodes are a lot simpler
than in the completely unconstrained mesh network.
The tree-like organization also seems to avoid
another conceptual problem with the fully
unconstrained network which is bandwidth sharing.
If you are a client in a full mesh, your node
must accept routing traffic from other nodes.
Thus a goodish portion of your bandwidth and battery power may be consumed by traffic going
through your client - but it's not your traffic.
I'd guess that most people would not want to act
as a router and be draining power pretty much
fulltime. Makes more sense to have a wireless
self-organizing infrastructure that can provide
bandwidth to clients that cruise within range.
There were a few misleading comments about power
in earlier emails. Cell phones typical draw
about 2 watts when transmitting. That exceeds
the current capacity of the battery. They actually charge a capacitor from the battery between time slots and drain the capacitor during transmission. 802.11 devices have lower peak current drains, and they continue to get better. The most important technique in
Next-generation
I think it is important to point out that 11b only has 3 channels to operate in. That doesn't give you much routing diversity when you need a lot of overlapping transmitters to create a useful (and thus redundant) mesh. But when you add 11a and can use the higher bandwidth ofdm codec in either the 11a bands or in the 11b bands (where they call it 11g), then you have more than a dozen channels that can be operating simultaneously. It seems obvious to me that this kind of channel diversity will be needed to successfully deploy a good mesh.
Porno (Score:1)
Think could be a lot worse... last thing I need is some idiot streaming nudies next to me on the bus, with a crowd of his leering friend peering over our shoulders...
Sounds fine... except... (Score:1)
All your packets will flow over kit owned by other people. Other people you don't know and shouldn't trust. Yes, you may encrypt it all, but it can be stored to decrypt at leisure.
Your traffic can be throttled or disrupted by anyone who cares to do so.
Why should I use the battery of my mobile device to support your pr0n habit?
On another note... 3G vs 802.11. A friend and I spend a short while doing some back-of-a-napkin calculations about the issues. Given the typical range of an 802.11 AP, how many are needed to cover a freeway? How fast does a vehicle travelling at 70mph (UK motorway speed) move from one to another? How much time does the accessing device spend handing off from one AP to another? The results don't argue for 802.11 as a general replacement for 3G at all. Anna B