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How Wi-Fi Works
- pier25 9y agoI had to disable the ad blocker to get the nice web gl graphics. From a front end perspective I think this it's awesome. No so sure about the content though.
- jonathanbull 9y agoMirror: http://webcache.googleusercontent.com/search?q=cache:http://www.verizoninternet.com/bookmark/how-wifi-works/ http://webcache.googleusercontent.com/search?q=cache:http://...
- gruez 9y agogoogle cache doesn't do the page justice. most of the value is in its visualizations.
- jonathanbull 9y agoTrue, but better than the 503 I was receiving.
- dotancohen 9y agoThe cache now has the images, though it didn't when first posted. Honestly, the Google cache is _better_ than the original as it doesn't have the CPU-killing animations.
- emilfihlman 9y agoNo images for me :/
- marmshallow 9y agoThe Archive of it is better https://web.archive.org/web/20170723145452/http://www.verizoninternet.com/bookmark/how-wifi-works/ https://web.archive.org/web/20170723145452/http://www.verizo...
- dotancohen 9y agoThese guys should do a followup "How Load Balancing Works".
- sshanky 9y agoThis is beautiful, but probably still too complex for most of their customers. I wonder what their motive in putting this together was, as it must have been very expensive.
- Rjevski 9y agoMaybe the fact that as an internet provider it's their duty to explain how what they're selling works? Granted, "internet" doesn't mean Wi-Fi however their equipment includes a wireless access point so it's fair for them to provide documentation about how that works.
- gist 9y ago> it's their duty Not at all. No more than a car manufacturer has a 'duty' to explain how a car or a car engine works.
- serf 9y ago>No more than a car manufacturer has a 'duty' to explain how a car or a car engine works. It is their duty (car mfgs) in the sense that they need the customer to attribute value to their newest technology offerings. Honda made damn sure that consumers knew what 'VTEC' was when it was new. Toyota made sure to throw 'Hybrid Synergy Drive' around all day; along with an on-dash animation of the flow of electrons. We're all hearing all about how Teslas' auto-pilot works. I don't know if it's a duty unless you consider it as a duty to their shareholders to generate value or profit wherever possible.
- alsetmusic 9y agoVTEC and Synergy Drive are marketing terms, not established aspects of modern technology that consumers already know they want to purchase.
- Neliquat 9y agoVtec refers to a specific implementation of variable cam tech, not just marketing. Many people bought the vtec version of their honda for real performance and economy reasons. Hell, I installed one in my car that orihinally had the exact same displacement single cam motor. But I get your point.
- princekolt 9y ago"How Wi-Fi Works" --> 503 Service Unavailable Seems about right.
- Kenji 9y agoHahaha, I was about to post just that. Made me laugh. Reminds me of my time at university... during breaks and boring lectures, WiFi was impossible to use because of the load. You could probably measure how boring a lecture is by recording WiFi latency and stability parameters.
- dzhiurgis 9y agoI've got that once it requested WebGL access and I've clicked "Never for this site". Refreshed and worked fine.
- microwavecamera 9y agoVerizon is trying to give you the authentic experience of how your WiFi works when you're on their network.
- bdcravens 9y agoSpeaking of how wifi works, I learned something interesting about wifi and Verizon's partner in many things, Comcast: Last night I notified my home Internet acting funny, and learned that the admin interface for my Comcast router had username "admin", password "password". SMH.
- joshumax 9y agoIf you want to hear something else scary, I dumped the firmware on my modem a little while back and started exploring it: https://twitter.com/joshumax/status/860712276717748225 https://twitter.com/joshumax/status/860712276717748225
- deleted 9y ago[deleted]
- willstrafach 9y agoDid you need to do anything special to get shell access?
- joshumax 9y agoJust the basics. Plugged in my 'scope and started probing some debug headers that looked a lot like they'd be for UART, check if one is Tx and is sending out data, figure out the baud rate, hook up Rx, Tx, and GND on my UART dongle to the correct headers, and modify the bootsting in Cisco preboot to spawn a serial console which landed me into busybox as root :)
- voltagex_ 9y ago> Just the basics. Followed by the use of >=$100 of hardware and some not-beginner skills. Snark aside, I highly recommend anyone remotely interested in what is going on in your modem/router to have a go at this. You don't need the scope if you're okay with trial and error and it's pretty hard to break anything as long as you don't connect the 3.3/5V line to start with.
- hatsunearu 9y agothe radio stuff is pretty wrong; one glaring one is that PSK is pretty much not used anymore, it's all OFDM.
- rayiner 9y agoOFDM is orthogonal to PSK (hah). PSK is a modulation--a way of representing bits on a carrier wave. Another type of modulation is QAM. OFDM is a way of combining multiple sub-carriers (each modulated with PSK or QAM) into one signal in order to deal with multi-path distortion: https://www.csie.ntu.edu.tw/~hsinmu/courses/_media/wn_11fall/ofdm_new.pdf https://www.csie.ntu.edu.tw/~hsinmu/courses/_media/wn_11fall....
- tankenmate 9y agoSome systems even combine PSK and ASK (like QAM) but asymmetrically (called APSK), obviously though you start getting into diminishing returns; noise limiting the gains. Of course you are limited by Shannon's law. But depending on the transmission medium lower energy signals can be more resistant to noise, so you can use either probabilistic or dynamic symbol selection to reduce the effect noise has on the signal and hence increase the available error free bandwidth (error free symbol rate)[0]. [0] https://en.wikipedia.org/wiki/Constellation_shaping https://en.wikipedia.org/wiki/Constellation_shaping ; check the references and external links for more in depth explanations.
- mrb 9y agoStill, hatsunearu is correct. The page is grossly wrong, absolutely no modern WiFi modulation technique uses 8-PSK. Have a look at http://mcsindex.com/ http://mcsindex.com/ 11a/11n/11ac all use BPSK, QPSK, 16-QAM, 64-QAM, and (for 11ac only) 256-QAM.
- m-j-fox 9y agoI know. And not a word on forward-error correction, trellis codes, automatic gain control, beam steering or MU-MIMO. Is this for babies? They don't even touch on low-noise amplifiers. Much less DAC and ADC performance. Where's the link a primer on FFT?
- notgood 9y agoJust a reminder that Verizon its the biggest lobbyist against Net Neutrality[0] and if you do support it then it's probably wise to stay away from their services as far as possible. [0] https://www.dailydot.com/layer8/lobbyists-net-neutrality-fcc/ https://www.dailydot.com/layer8/lobbyists-net-neutrality-fcc...
- mrb 9y agoAs hatsunearu said, the radio modulation described is grossly incorrect. WiFi never uses 8-PSK (encoding 3 bits per symbol). 802.11n and 11ac encode 1/2/4/6/8 bits using a BPSK/QPSK/16-QAM/64-QAM/256-QAM symbol (256-QAM is for 11ac only). The modulation scheme is negotiated based on signal quality. Here is a quick reference: http://mcsindex.com/ http://mcsindex.com/ (MCS = modulation coding scheme) On Linux you can find the MCS negotiated with "iw dev wlan0 link | grep -i mcs" 14 channels are defined in the 2.4GHz band. For example channel 6 is centered on 2437 MHz. Each channel is 20MHz wide and divided in 52 "data" subcarriers, each occupying a different frequency and spaced out by 312.5 kHz (52 × 312.5 kHz is less than 20 MHz because there are "control" subcarriers and additional spacing.) So 52 different symbols can be sent in parallel at the same time, which is what we call OFDM https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing https://en.wikipedia.org/wiki/Orthogonal_frequency-division_... (basically, I'm simplifying!) Remember this is for just 1 channel. So with 14 channels each composed of 52 subcarriers, we could have 728 symbols transmitted at the same time. If they are 256-QAM symbols that's basically 728 × 8 = 5824 bits being transmitted at the same time in the air. And they will all be received and demodulated independently. This high level of parallelism of OFDM is how WiFi can achieve very high throughput. Then, with wide channels of 40 MHz, which basically aggregate two 20 MHz channels, we get a few more data subcarriers because we don't need as many control subcarriers so a few of them become used as data subcarriers. Hence a 40 MHz channel will have not 52 × 2 = 104 but actually 108 data subcarriers. And 802.11ac defines 80 MHz and 160 MHz channels with respectively 234 and 468 data subcarriers. Let's calculate the maximum usable throughput of a single 802.11ac 160 MHz channel using 256-QAM modulation... It sends 468 symbols at the same time on 468 data subcarriers. Each symbol encodes 8 bits and takes in the best case 3.6us to be transmitted: 3.2us for the actual symbol + a short guard interval of 0.4us (the GI is normally 0.8us but can be a short GI of 0.4us if negotiated). The raw physical bitrate is: 1/3.6e-6 × 468 × 8 = 1.04 Gbit/s However there is a mandatory error correction which is 5/6 in the best case so the actual usable bandwidth is: 1.04 × 5/6 = 866.67 Mbit/s
- dzhiurgis 9y ago> 1.04 × 5/6 = 866.67 Mbit/s This is bang on what most hardware is able to achieve. I am curious Apple haven't jumped into 512-QAM yet. Partly stopped me from upgrading my fiber to 1Gb/s.
- arikrak 9y agoI was looking at this and thought it looked nice but then my computer froze so maybe they overdid the 3D graphics a bit?
- blocker_chain 9y agoLol I had the same thoughts
- dotancohen 9y agoTry the Google cache, it now has the images but not the animations: http://webcache.googleusercontent.com/search?q=cache:http://www.verizoninternet.com/bookmark/how-wifi-works/ http://webcache.googleusercontent.com/search?q=cache:http://...
- andrenotgiant 9y agoThis is (good) SEO linkbait. Someone at Verizon got $10k to spend getting it created by saying it will boost organic search traffic to Verizon. Right now (during link-building phase) they keep the page completely separate from rest of site. Later, (after most links are created) they'll change it. Not sure whether the goal is just to generally build authority to VerizonInternet, or to get this URL ranking for wifi keywords. (Seems more likely the former.)
- vxNsr 9y agoWould it be accurate to assume this is gonna be used as ammo in the net neutrality debate of the next few weeks?
- srtjstjsj 9y agoAre you saying they'll change the content later, and won't lose seojuice for that?
- ejo3 9y agoThat page probably cost a lot more than 10K.
- moondev 9y agoAbsolutely. They did a great job too
- bigbugbag 9y agoBrowser could not initialize WebGL For more info visit blend4web.com/doc/en/problems_and_solutions.html#problems-upon-startup Maybe they could have done a good job instead of a great job and this page would actually work. Not mention the font size issues and overlapping text, luckily they provide images at the bottom that do not have the problem. When you have to provide images at the bottom as a workaround, it usually means you know there are issues with the page and the job is not that great. Then again, as pointed in other comments here some of the technical information is incorrect or just plain wrong.
- 9y ago
- Piccollo 9y agoWhy did CSS stop working
- nvahalik 9y agoCan someone explain the natural resonance of walls of talked about with regards to 5Ghz?
- deepsun 9y agoDoes anyone know, if I'm on a WPA2-PSK wi-fi, do other devices that are also on the same network can "sniff" my traffic. For unprotected networks it's obvious, but what about protected?
- m-j-fox 9y agoIt wouldn't be a good system if they could. You have to worry more about wired Ethernet which can also be encrypted but rarely is.
- GrayShade 9y agoAs far as I know, they can [1]. Once you're connected to the network you can sniff out everything from clients that connect after you. The standard response to this is that you're safe since the eavesdropper needs to know the shared key. You can look into setting up WPA2-Enterprise if you're worried about that. FreeRADIUS doesn't seem particularly hard to configure. [1] https://superuser.com/a/156969 https://superuser.com/a/156969
- ryan-c 9y agoYes, other devices on the same network (using WPA2-PSK) can sniff your traffic. It's possible to prevent this with WPA2-Enterprise.
- detaro 9y agoYes, if you know the PSK (=password) and can capture the initial handshake (which is easy, since you can just force-disconnect a client so it has to do a new one) you can decrypt it. (If I remember correctly, Wireshark has this built in, so you can try it for yourself if you are curious)
- voltagex_ 9y agoI'm assuming you mean a malicious device can force a deauth on another client (or more usually, all other clients) and then capture the packets as they reconnect. If so, is there a way to detect this? Is there any way to protect against this? I'm assuming client isolation makes it more difficult.
- srtjstjsj 9y agowebsite crashes chrome on windows after a few seconds.
- KozmoNau7 9y agoTL;DR: It doesn't.
- anilakar 9y agoStopped reading at "Wi-Fi antennas send information". Antennas don't send anything, they just match the impedance of the feedline into that of the medium.
- Yizahi 9y agoIn my experience it doesn't. My every attempt at improving this shit ends up in laying more wires everywhere.
- Ajedi32 9y agoGetting a 404 now. Any idea where the page went? (Here's an archive link: https://web.archive.org/web/20170723145452/http://www.verizoninternet.com/bookmark/how-wifi-works/ https://web.archive.org/web/20170723145452/http://www.verizo...)
- glenneroo 9y agoAre you sure it was a 404? I'm getting a 503 (Service Temporarily Unavailable). Not that it really matters...
- deleted 9y ago[deleted]
- founderguy 9y agoPretty sure that domain isn't owned by Verizon. Looks like an authorized seller creating content to try to build authority.
- andrenotgiant 9y agoLooks like it is actually owned by Verizon, see email contact on WHOIS http://whois.domaintools.com/verizoninternet.com http://whois.domaintools.com/verizoninternet.com
- Web1Dollar 9y agowi-Fi is a best device! but is can work slow than wire. https://www.webhostingonedollar.com/ https://www.webhostingonedollar.com/ visit for getting more detail about hosting plan.