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📱 | Twitter has been troubled since dawn on July 7st, and you can't use it from your smartphone via Wi-Fi?


From the early hours of July 7st, Twitter failed, and you can't use it from your smartphone via Wi-Fi?

If you write the contents roughly
The cause is unknown, but many reports seem to be unable to connect via Wi-Fi, and it seems that there are many cases where the failure can be avoided by turning off Wi-Fi on the smartphone and switching to mobile communication.

Twitter has been out of order since dawn on July 7st.The cause is unknown, but many reports go through Wi-Fi ... → Continue reading

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Wikipedia related words

If there is no explanation, there is no corresponding item on Wikipedia.


Wi-FiWhat is (Wi-Fi)?無線 LANAboutRegistered trademarkIs[1].Wi-Fi Alliance(The United States of AmericaBy an industry group based in)International standardIsIEEE 802.11A name that indicates that interconnection between devices using the standard has been approved.


Australian Federal Institute for Scientific and Industrial ResearchI was studying astronomy and space science at (CSIRO)John O'SullivanIs said to be the father of Wi-Fi.O'Sullivan was CSIRO at the time,Mini black holeI was doing research.atomCaused by an explosion of a mini black hole of the sizeRadio waveFor experiments to detectnoiseThere was a need for a method that would not be affected by such factors as much as possible.And he created a wireless network for that.The experiment ended in failure, but Wi-Fi was born as a by-product.[2].


When wireless LAN was commercialized, interconnection was not guaranteed between products from different lineups, even if they were from the same manufacturer.For this reason, it is difficult for the user to know whether or not the connection is actually possible when considering the purchase, and there is a problem in the spread of wireless LAN to the general public.

To be certified as Wi-Fi, you need to be certified by an organization called the Wi-Fi Alliance.[3].. The Wi-Fi Alliance is an organization that solves this problem so that the technology can mature according to the needs of users.1999Started under the name of Wireless Ethernet Compatibility Alliance (WECA)2000Certification work started in March.Since then, the awareness of Wi-Fi has increased.2002Renamed to Wi-Fi Alliance in October.

The Wi-Fi Alliance has created a brand to allow users to see that one product can be used in combination with other products that display the same brand.Certified devices are permitted to use the Wi-Fi logo, which is a registered trademark of the Wi-Fi Alliance.

Wi-Fi names seek catchy names (rather than dry standard names such as IEEE 802.11)Hi-Fi(Hi-fi,British: High Fidelity) Was named after the rhyme. The interpretation of the origin of "abbreviation of Wireless Fidelity" was added after the name because "it is bad to have no meaning".[4].

Difference between "Wi-Fi" and "wireless LAN"

"Wireless LAN" in a narrow sense[Annotation 1]The difference between (IEEE 802.11 standard wireless LAN) and "Wi-Fi" is whether or not the product displays the Wi-Fi CERTIFIED logo. In order to display the Wi-Fi CERTIFIED logo on the product, it is necessary to be certified, and those who are not certified cannot be called Wi-Fi even if they have the same function.In the example of a well-known productNintendo DS-Nintendo DS LiteIs not authenticated.

For example,FONThe device received Wi-Fi certification2008It was November, and before that, FON couldn't call itself Wi-Fi.Conversely, the WPA version 11 specification defined by Wi-Fi Allience is based on the draft of IEEE 1, and the old WPA version 802.11 does not meet IEEE 1 (WPA version 802.11 meets IEEE 2). ..

Wi-Fi authentication type

  • Wi-Fi CERTIFIED ac
    • Compliant with IEEE802.11ad
  • Wi-Fi Direct
  • Wi-Fi Enhanced Open
  • Protected Management Frames
  • IBSS with Wi-Fi Protected Setup
  • Passpoint
  • Easy Connect Wi-Fi
  • Wi-Fi Protected Setup
  • Miracast
  • Wi-Fi Aware
  • Wi-Fi Location
  • Wi-Fi Agile Multiband
  • Wi-Fi Easy Mesh
  • Wi-Fi Optimized Connectivity
  • Wi-Fi TimeSync
  • Wi-Fi Vantage
  • Wi-Fi Home Design

Numbering standard

Corresponding standardFormal nameAbbreviation
IEEE 802.11nWi-Fi CERTIFIED 4Wi-Fi 4
IEEE 802.11acWi-Fi CERTIFIED 5Wi-Fi 5
IEEE 802.11axWi-Fi CERTIFIED 6Wi-Fi 6
WiFi 6E

In October 2018, the Wi-Fi Alliance decided to introduce 10, 4, and 5 numbering in the certification program name, and announced that product certification will start in 6.[5][6][7]..There is no change in the name of the communication standard itself (IEEE 802.11 / n / ac / ax).However, the Wi-Fi Alliance has made this numbering more widespread.OSIt is recommended to use it on terminals such as smartphones and smartphones.[8].

At the beginning of the introduction of numbering, numbering 1 to 3 and 7 and later are undefined.

Wi-Fi 4 and Wi-Fi 5 are for backward compatibility and do not automatically replace the certification of existing IEEE 802.11n / ac products.[8]. In 2020, Wi-Fi 2.4E, which uses the 5GHz band in addition to the 6GHz and 6GHz bands, was announced.[9].


Wi-Fi guarantees interoperability between devices from different manufacturers, so computers, feature phones, smartphones, tablets,PDAVarious devices such as these can use wireless LAN to connect to the Internet via an access point, for example.access pointThe area where you can connect to the InternetHot spotThat is.Hotspots can range from just inside a room to several kilometers by stacking multiple access points.Wireless LAN is alsoMesh networkCan be used to build.Both architectures are used in community networks.

Also, in this standard, communication terminals are directly connected to each other without going through an external communication device such as an access point.P2PThere is a mode called (wireless ad hoc network), which has been adopted in home appliances and game consoles.Generally, it is called ad hoc mode, ad hoc connection, or the like.

Future direction

Initially envisioned mobile computing devices such as laptopsLocal Area NetworkBesides,PSP-PS VitaIt is also installed in mobile game consoles such as feature phones, smartphones, smart TVs, music players, and home appliances such as digital cameras.

By connecting to an access point whose interoperability is guaranteed by Wi-Fi, in addition to the Internet, various wireless LAN devices such as Internet telephones and game devices are connected and used. Using Wi-Fid Wi-Fi,FLET'S SPOT, FON,Softbank Wi-Fi spot,au Wi-Fi SPOTMany paid / freePublic wireless LANExists.

In addition, Mobile phoneDerived from the net3G(HSPA)・LTEAnd a wide area version of Wi-FiMobile WiMAXHigh-speed radio access network likeMobile broadbandAs the backbone ofSecondary batterySmall size with built-inaccess point"Mobile Wi-Fi routerProducts have emerged, complementing the area expansion that is a weakness of Wi-Fi.Recently, Wi-Fi for home use has been released, and it is talked about that you can connect to the Internet just by plugging it into an outlet.

Wi-Fi for game consoles

Some game consoles and handheld game consoles use Wi-Fi technology to enhance the enjoyment of games.


[How to use footnotes]

注 釈

  1. ^ "Wireless LAN" in a broad sense includes those based on the IEEE802.15 series and the like.


  1. ^ Registered under the name of "Wi-Fi Alliance" including the logo No. 4427605
  2. ^ Wi-fi, dual-flush loos and eight more Australian inventions --BBC NEWS Retrieved February 2018, 10
  3. ^ Stallings, William (2016). Foundations of modern networking: SDN, NFV, QoE, IoT, and CloudFlorence Agboma, Sofiene Jelassi. Indianapolis, Indiana. ISBN 978-0-13-417547-8. OCLC 927715441. https://www.worldcat.org/oclc/927715441 
  4. ^ Wi-Fi isn't short for "Wireless Fidelity" --Boing Boing Retrieved February 2014, 6
  5. ^ Impress Corporation (July 2018, 10). "802.11ax is called" Wi-Fi 6 ", 11ac is" Wi-Fi 5 ", 11n is" Wi-Fi 4 "Wi-Fi Alliance will start certification from 2019" (Japanese). INTERNET Watch. https://internet.watch.impress.co.jp/docs/news/1146263.html 2018/10/5Browse. 
  6. ^ "Wi-Fi 6 | Wi-Fi Alliance" (English). www.wi-fi.org. 2018/10/5Browse.
  7. ^ "Wi-Fi Alliance® introduces Wi-Fi 6 | Wi-Fi Alliance" (English). www.wi-fi.org. 2018/10/5Browse.
  8. ^ a b "Next-generation Wi-Fi "IEEE 802.11ax" becomes "Wi-Fi 6", "n" becomes "4", "ac" becomes "5" ── Wi-Fi Alliance"ITmedia NEWS".2018/10/5Browse.
  9. ^ "Wi-Fi Alliance® brings Wi-Fi 6 into 6 GHz | Wi-Fi Alliance". www.wi-fi.org. 2022/8/9Browse.

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