{"id":84590,"date":"2020-06-09T01:42:40","date_gmt":"2020-06-08T23:42:40","guid":{"rendered":"https:\/\/prohoster.info\/blog\/administrirovanie\/samoe-glavnoe-v-wi-fi-6-net-seryozno"},"modified":"2020-06-09T01:42:40","modified_gmt":"2020-06-08T23:42:40","slug":"samoe-glavnoe-v-wi-fi-6-net-seryozno","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/administrirovanie\/samoe-glavnoe-v-wi-fi-6-net-seryozno","title":{"rendered":"Nejd\u016fle\u017eit\u011bj\u0161\u00ed v\u011bc v Wi-Fi 6. Opravdu.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Ahoj.<\/p>\n

Pokud v\u011b\u0159it teorii jednoduchosti od Einsteina, hlavn\u00edm ukazatelem porozum\u011bn\u00ed t\u00e9matu je schopnost maxim\u00e1ln\u011b jednodu\u0161e ho vysv\u011btlit. I v tomto p\u0159\u00edsp\u011bvku se pokus\u00edm co nejjednodu\u0161eji a podrobn\u011bji vysv\u011btlit funk\u010dnost jedin\u00e9 sou\u010d\u00e1sti nov\u00e9ho standardu, kterou si Wi-Fi Alliance jaksi pova\u017euje za nedostate\u010dnou pro zm\u00ednku v infografice o nov\u00fdch mo\u017enostech Wi-Fi 6, a\u010dkoliv, jak brzy zjist\u00edme, je velmi d\u016fle\u017eit\u00e1 a podstatn\u00e1. Nen\u00ed zde v\u0161e dostate\u010dn\u011b hlubok\u00e9 a rozhodn\u011b neobs\u00e1hl\u00e9 (proto\u017ee j\u00edst slona po \u010d\u00e1stech je i tak n\u00e1ro\u010dn\u00e9), ale douf\u00e1m, \u017ee si z m\u00fdch slovn\u00edch cvi\u010den\u00ed odneseme n\u011bco nov\u00e9ho a zaj\u00edmav\u00e9ho.<\/p>\n

Ten zn\u00e1m\u00fd 802.11ax, kter\u00fd o\u010dek\u00e1v\u00e1me ze dne na den u\u017e minim\u00e1ln\u011b druh\u00fd rok, p\u0159in\u00e1\u0161\u00ed spoustu nov\u00e9ho a fascinuj\u00edc\u00edho. Ka\u017ed\u00fd, kdo se o n\u011bm chce zm\u00ednit, stoj\u00ed v\u017edy p\u0159ed volbou: bu\u010f provede p\u0159ehled s mno\u017estv\u00edm zkratek a akronym\u016f, sna\u017e\u00ed se nezapl\u00e9st se ve slo\u017eit\u00fdch mechanismech ka\u017ed\u00e9ho z nich, nebo se zam\u011b\u0159it na hodinovou prezentaci o n\u011b\u010dem jednom, co autorovi p\u0159ipad\u00e1 nejzaj\u00edmav\u011bj\u0161\u00ed. Riskuji j\u00edt je\u0161t\u011b d\u00e1l: v\u011bt\u0161ina m\u00e9 pozn\u00e1mky bude v\u011bnov\u00e1na dokonce ne nov\u00e9mu!
\n<\/a><\/noindex>
\nTak\u017ee u\u017e v\u00edce ne\u017e dvacet let \u010d\u00e1st bezdr\u00e1tov\u00fdch s\u00edt\u00ed pro p\u0159enos dat se stav\u00ed na z\u00e1klad\u011b mno\u017estv\u00ed standard\u016f rodiny 802.11. A jako ka\u017ed\u00fd sebe\u00factyhodn\u00fd prezent\u00e1tor bych m\u011bl trochu rekonstruovat \u010dasovou osu cel\u00e9 t\u00e9to \u0159et\u011bzce ud\u00e1lost\u00ed, kter\u00e1 dala sv\u011btu miliardy kompatibiln\u00edch za\u0159\u00edzen\u00ed \u2014 ale jako autor, kter\u00fd si v\u00e1\u017e\u00ed sv\u00fdch \u010dten\u00e1\u0159\u016f, riskuji to tentokr\u00e1t neud\u011blat. Nicm\u00e9n\u011b by bylo dobr\u00e9 n\u011bkter\u00e9 v\u011bci si p\u0159ipomenout. <\/p>\n

V\u0161echny iterace Wi-Fi kladly d\u016fraz na spolehlivost, nikoliv na maxim\u00e1ln\u00ed propustnost. To vypl\u00fdv\u00e1 z mechanismu p\u0159\u00edstupu k m\u00e9di\u00edm (CSMA\/CA), kter\u00fd nen\u00ed z hlediska vyt\u011bsn\u011bn\u00ed posledn\u00edch kilobit\u016f za sekundu z p\u0159enosov\u00e9ho m\u00e9dia zrovna optim\u00e1ln\u00ed (podrobn\u011bji o nedokonalostech sv\u011bta obecn\u011b a Wi-Fi zejm\u00e9na si m\u016f\u017eete p\u0159e\u010d\u00edst v \u010dl\u00e1nku m\u00e9ho b\u00fdval\u00e9ho kolegy skhomm<\/a><\/noindex> tady<\/a><\/noindex>), ale neuv\u011b\u0159iteln\u011b odoln\u00e9 t\u00e9m\u011b\u0159 za jak\u00fdchkoliv podm\u00ednek. Opravdu lze poru\u0161it t\u00e9m\u011b\u0159 v\u0161echny z\u00e1sady n\u00e1vrhu Wi-Fi s\u00edt\u00ed \u2013 a v takov\u00e9 s\u00edti stejn\u011b prob\u00edh\u00e1 v\u00fdm\u011bna dat! Cel\u00fd mechanismus, kter\u00fd zabezpe\u010duje, \u017ee klienti Wi-Fi s\u00edt\u011b mohou p\u0159en\u00e1\u0161et a\/nebo p\u0159ij\u00edmat sv\u00e9 datov\u00e9 pakety, je zam\u011b\u0159en na zabezpe\u010den\u00ed toho, co se v angli\u010dtin\u011b naz\u00fdv\u00e1 term\u00ednem s t\u011b\u017eko p\u0159elo\u017eiteln\u00fdm zabarven\u00edm technokracie, robustness. Cel\u00e1 vrstva p\u0159ekryt\u00ed zlep\u0161en\u00fdch modulac\u00ed, agregace r\u00e1mc\u016f s daty (ne \u00fapln\u011b, ale budi\u017e!) nad\u00e1le funguje ji\u017e po dvou z\u00e1kladn\u00edch principech 802.11, kter\u00e9 zabezpe\u010duj\u00ed tuto bezkonkuren\u010dn\u00ed spolehlivost:<\/p>\n

    \n
  1. \u201eDokud jeden mluv\u00ed \u2013 ostatn\u00ed ml\u010d\u00ed\u201c;<\/li>\n
  2. \u201eV\u0161echno krom\u011b dat se \u0159\u00edk\u00e1 pomalu a srozumiteln\u011b.\u201c<\/li>\n<\/ol>\n

    \nDruh\u00fd bod zp\u016fsobuje mnohem v\u011bt\u0161\u00ed \u0161kody na propustnosti s\u00edt\u011b, ne\u017e by se na prvn\u00ed pohled mohlo zd\u00e1t. Tady je skv\u011bl\u00fd obr\u00e1zek, kter\u00fd ilustruje jeden odeslan\u00fd kousek dat v s\u00edti Wi-Fi:<\/p>\n

    \"Nejd\u016fle\u017eit\u011bj\u0161\u00ed
    \n
    \nPoj\u010fme si vysv\u011btlit, co to znamen\u00e1 pro oby\u010dejn\u00e9 lidi, kte\u0159\u00ed nev\u011bd\u00ed, kolik stran m\u00e1 standard 802.11-2016. Ta rychlost p\u0159enosu dat, kterou syst\u00e9m uv\u00e1d\u00ed v vlastnostech bezdr\u00e1tov\u00e9 s\u00edt\u011b a kterou na krabic\u00edch p\u0159\u00edstupov\u00fdch bod\u016f zobrazuje marketing ka\u017ed\u00fd v\u00fdrobce (no, jist\u011b jste to u\u017e vid\u011bli \u2013 1,7 Gb\/s! 2,4 Gb\/s! 9000 Gb\/s!), nen\u00ed jen vrcholn\u00e1 a maxim\u00e1ln\u00ed p\u0159i 100% vyt\u00ed\u017een\u00ed p\u0159enosu, ale je to tak\u00e9 rychlost, p\u0159i kter\u00e9 bude odes\u00edl\u00e1na pouze modr\u00e1 \u010d\u00e1st v tomto kr\u00e1sn\u00e9m grafu. V\u0161echno ostatn\u00ed bude p\u0159en\u00e1\u0161eno rychlost\u00ed, kter\u00e1 se anglicky naz\u00fdv\u00e1 management rate (a rusky tak\u00e9, proto\u017ee p\u0159eklady takov\u00fdch v\u00fdraz\u016f hroz\u00ed dal\u0161\u00edm nedorozum\u011bn\u00edm mezi in\u017een\u00fdry), a kter\u00e1 je ni\u017e\u0161\u00ed nejen o n\u011bkolik n\u00e1sobk\u016f, ale o STOVKY<\/b> n\u00e1sobk\u016f. Nap\u0159\u00edklad bez jak\u00fdchkoliv dodate\u010dn\u00fdch nastaven\u00ed s\u00ed\u0165 na 802.11ac, kter\u00e1 m\u016f\u017ee pracovat s klienty p\u0159i kan\u00e1lov\u00e9 rychlosti 1300 Mb\/s, p\u0159en\u00e1\u0161\u00ed ve\u0161ker\u00e9 \u0159\u00eddic\u00ed informace (v\u0161echno, co nen\u00ed modr\u00e9 na na\u0161em st\u00e1le v\u00edce stra\u0161n\u00e9m grafu) p\u0159i management rate 6 Mb\/s. O v\u00edc ne\u017e dv\u011bst\u011bkr\u00e1t pomaleji! <\/p>\n

    Logick\u00e1 ot\u00e1zka \u2013 jak\u00e9ho, omlouv\u00e1m se, \u010d\u00edsla a m\u011bs\u00edce se mohla tato zni\u010duj\u00edc\u00ed my\u0161lenka v\u016fbec dostat do standardu, podle n\u011bho\u017e pracuj\u00ed miliardy za\u0159\u00edzen\u00ed po cel\u00e9m sv\u011bt\u011b? Logick\u00e1 odpov\u011b\u010f \u2013 kompatibilita, kompatibilita, kompatibilita! S\u00ed\u0165 na nejnov\u011bj\u0161\u00edm p\u0159\u00edstupov\u00e9m bod\u011b by m\u011bla zajistit mo\u017enost fungov\u00e1n\u00ed i pro desetilet\u00e1 a dokonce patn\u00e1ctilet\u00e1 za\u0159\u00edzen\u00ed, a pr\u00e1v\u011b ve v\u0161ech t\u011bchto \u201ene-modr\u00fdch\u201c kousc\u00edch let\u00ed informace, kterou pomal\u00e1 star\u00e1 za\u0159\u00edzen\u00ed usly\u0161\u00ed, spr\u00e1vn\u011b pochop\u00ed a nebudou se b\u011bhem superrychl\u00fdch datov\u00fdch p\u0159enos\u016f sna\u017eit p\u0159edat sv\u00e9. Robustnost si \u017e\u00e1d\u00e1 ob\u011bti!<\/p>\n

    Nyn\u00ed jsem p\u0159ipraven poskytnout ka\u017ed\u00e9mu z\u00e1jemci nezbytn\u00fd n\u00e1stroj, aby mohl b\u00fdt zd\u011b\u0161en bezc\u00edln\u011b ztr\u00e1cej\u00edc\u00edmi se v modern\u00edm Wi-Fi potenci\u00e1ln\u011b p\u0159edan\u00fdmi megabity \u2013 to se stalo ji\u017e povinnou znalost\u00ed v p\u0159\u00edslu\u0161n\u00fdch in\u017een\u00fdrsk\u00fdch kruz\u00edch. WiFi AirTime Calculator<\/b> od norsk\u00e9ho nad\u0161ence 802.11 Gjermunda Raaena. Je k dispozici na tento odkaz<\/a><\/noindex> \u2013 v\u00fdsledek jeho pr\u00e1ce vypad\u00e1 p\u0159ibli\u017en\u011b takto:<\/p>\n

    \"Nejd\u016fle\u017eit\u011bj\u0161\u00ed
    \n
    \n\u0158\u00e1dek 1 \u2013 \u010das pot\u0159ebn\u00fd k p\u0159enosu datov\u00e9ho paketu o d\u00e9lce 1512 bajt\u016f za\u0159\u00edzen\u00edm 802.11n v \u0161\u00ed\u0159ce p\u00e1sma 20 MHz.<\/p>\n

    \u0158\u00e1dek 2 \u2013 \u010das pot\u0159ebn\u00fd k p\u0159enosu stejn\u00e9ho paketu za\u0159\u00edzen\u00edm se stejnou ant\u00e9nn\u00ed charakteristikou, ale kter\u00e9 ji\u017e pracuje podle standardu 802.11ac v kan\u00e1lu o \u0161\u00ed\u0159ce 80 MHz.<\/p>\n

    Jak je to mo\u017en\u00e9 \u2013 \"zneu\u017eito\" \u010dty\u0159ikr\u00e1t v\u00edce r\u00e1diov\u00e9ho spektra, maxim\u00e1ln\u00ed modulace se zkomplikovala z 64QAM na 256QAM, kan\u00e1lov\u00e1 rychlost je v\u011bt\u0161\u00ed o \u0160EST<\/b> kr\u00e1t (433 Mb\/s m\u00edsto 72 Mb\/s), a vyhr\u00e1no bylo maxim\u00e1ln\u011b 25 % \u010dasu obsazenosti r\u00e1diov\u00e9ho spektra? <\/p>\n

    Pamatujete si na kompatibilitu a dva principy 802.11?<\/p>\n

    Dob\u0159e, jak m\u016f\u017eeme napravit takovou nespravedlnost a pl\u00fdtv\u00e1n\u00ed \u2013 zept\u00e1me se sami sebe, jak se asi ptal ka\u017ed\u00fd pracovn\u00ed t\u00fdm IEEE, kdy\u017e za\u010dal vytv\u00e1\u0159et standard? Na mysli p\u0159ich\u00e1z\u00ed n\u011bkolik logick\u00fdch cest:<\/p>\n

      \n
    1. Zrychlit p\u0159enos dat v \"zelen\u00e9m\" kousku grafu.<\/i><\/b> To se d\u011bl\u00e1 p\u0159i ka\u017ed\u00e9m vyd\u00e1n\u00ed standardu, proto\u017ee velk\u00e1 \u010d\u00edsla dob\u0159e vypadaj\u00ed na krabic\u00edch. V praxi, jak jsme pr\u00e1v\u011b poznamenali, d\u00e1v\u00e1 kone\u010dn\u00fd p\u0159\u00edr\u016fstek \u2013 i kdy\u017e zrychl\u00edme kan\u00e1lovou rychlost na sto tis\u00edc milion\u016f gigabit\u016f za nanosekundu, v\u0161echny ostatn\u00ed \u010d\u00e1sti grafu nikam nezmiz\u00ed. A pr\u00e1v\u011b proto doporu\u010duji p\u0159i v\u0161ech p\u0159\u00edb\u011bz\u00edch o nov\u00fdch standardech 802.11 vynechat odstavce, kde se zmi\u0148uj\u00ed megabity za sekundu.<\/li>\n
    2. Zrychlit v\u0161echny ostatn\u00ed \u010d\u00e1sti grafu.<\/i><\/b> Opravdu, pokud alespo\u0148 zdvojn\u00e1sob\u00edme rychlost, kterou se p\u0159en\u00e1\u0161\u00ed v\u0161echno \"ne-zelen\u00e9\" (nebo \"ne-modr\u00e9\", pokud se je\u0161t\u011b d\u00edv\u00e1te na p\u0159edchoz\u00ed obr\u00e1zek), z\u00edsk\u00e1me o n\u011bco m\u00e9n\u011b ne\u017e 50% n\u00e1r\u016fst skute\u010dn\u00e9 propustnosti \u2014 samoz\u0159ejm\u011b se ztr\u00e1tou kompatibility s za\u0159\u00edzen\u00edmi a je\u0161t\u011b n\u011bkolika detaily, o kter\u00fdch se dozv\u00edte, kdy\u017e se za\u010dnete p\u0159ipravovat na zkou\u0161ku o hrd\u00e9m titulu CWNA \ud83d\ude42 Spoiler: ne v\u017edy to bude mo\u017en\u00e9, pokud si to d\u016fkladn\u011b promysl\u00edte a pochop\u00edte, k \u010demu to povede. Vlastn\u011b to poru\u0161uje jeden ze dvou princip\u016f 802.11, tak\u017ee s t\u00edm je t\u0159eba b\u00fdt velmi opatrn\u00fd!<\/li>\n
    3. Slepit dohromady n\u011bkolik takov\u00fdch r\u00e1mc\u016f se zelen\u00fdmi \u010d\u00e1stmi.<\/i><\/b> \u010c\u00edm del\u0161\u00ed je zelen\u00e1 \u010d\u00e1st, t\u00edm efektivn\u011bji funguje zvy\u0161ov\u00e1n\u00ed kan\u00e1lov\u00e9 rychlosti. Ano, to je zcela funk\u010dn\u00ed strategie, kter\u00e1 vznikla u\u017e v 802.11n a je jedn\u00edm z n\u011bkolika z\u00e1kladn\u00edch kamen\u016f jej\u00ed revolu\u010dnosti. Probl\u00e9m je ale v tom, \u017ee, za prv\u00e9, \u0159ada aplikac\u00ed na takovou agregaci v\u016fbec nedb\u00e1 (nap\u0159\u00edklad zm\u00edn\u011bn\u00fd \u017erav\u00fd Voice over Wi-Fi), a za druh\u00e9, \u0159ada za\u0159\u00edzen\u00ed tak\u00e9 na ni ned\u00e1. Jednou jsem se rozhodl zachytit alespo\u0148 n\u011bkolik takov\u00fdch agregovan\u00fdch r\u00e1mc\u016f v re\u00e1ln\u00e9 s\u00edti firmy, ve kter\u00e9 pracuji, ale z >500k \"zachycen\u00fdch\" sn\u00edmk\u016f bylo agregovan\u00fdch pr\u00e1v\u011b nula. Pravd\u011bpodobn\u011b je to probl\u00e9m m\u00e9 metodologie sb\u011bru dat, ale jsem p\u0159ipraven ji probrat s k\u00fdmkoli, kdo bude m\u00edt z\u00e1jem o osobn\u00ed rozhovor!). <\/li>\n
    4. Poru\u0161it i prvn\u00ed ze dvou princip\u016f 802.11, za\u010d\u00ednaj\u00edc\u00ed mluvit, kdy\u017e mluv\u00ed n\u011bkdo jin\u00fd.<\/i><\/b> A tady p\u0159ich\u00e1z\u00ed na pomoc 802.11ax.<\/li>\n<\/ol>\n

      \nJak skv\u011bl\u00e9, kone\u010dn\u011b jsem se ve sv\u00e9m vypr\u00e1v\u011bn\u00ed o Wi-Fi 6 dostal k samotn\u00e9mu Wi-Fi 6! Pokud to st\u00e1le \u010dtete, bu\u010f mus\u00edte, nebo m\u00e1te opravdu z\u00e1jem. Tak\u017ee i kdy\u017e 802.11ax zd\u011bdil obrovskou \u010d\u00e1st p\u0159edchoz\u00edho v\u00fdvoje cel\u00e9 rodiny 802.11 (a nejen to, n\u011bkter\u00e9 skv\u011bl\u00e9 v\u011bci se objevily v\u016fbec v 802.16, co\u017e je WiMAX), n\u011bco v n\u011bm je p\u0159ece jen nov\u00e9 a origin\u00e1ln\u00ed. Obvykle se p\u0159i t\u011bchto slovech p\u0159ikl\u00e1d\u00e1 takov\u00fd obr\u00e1zek, kter\u00fd je dostupn\u00fd na str\u00e1nk\u00e1ch Wi-Fi Alliance:<\/p>\n

      \"Nejd\u016fle\u017eit\u011bj\u0161\u00ed
      \n
      \nJak jsem ji\u017e na za\u010d\u00e1tku zmi\u0148oval, v r\u00e1mci jednoho p\u0159ehledn\u00e9ho \u010dl\u00e1nku se m\u016f\u017eeme pod\u00edvat pouze na jeden z t\u011bchto kl\u00ed\u010dov\u00fdch bod\u016f, konkr\u00e9tn\u011b ani na jeden z t\u011bch, kter\u00e9 jsou uvedeny na obr\u00e1zku (p\u0159ekvapen\u00ed!). Jsem si jist\u00fd, \u017ee jste u\u017e \u010detli miliony stru\u010dn\u00fdch popis\u016f ka\u017ed\u00e9ho z t\u011bchto osmi kl\u00ed\u010dov\u00fdch prvk\u016f, j\u00e1 v\u0161ak budu pokra\u010dovat ve sv\u00e9m nudn\u011b dlouh\u00e9m vypr\u00e1v\u011bn\u00ed o tom, co vypl\u00fdv\u00e1 z OFDMA \u2014 o v\u00edcen\u00e1sobn\u00e9m p\u0159\u00edstupu k m\u00e9diu (MU-access control), kter\u00fd, jak vid\u00edme, se na infografiku v\u016fbec neve\u0161el. A to je velk\u00e1 \u0161koda!<\/p>\n

      V\u00edcen\u00e1sobn\u00fd p\u0159\u00edstup je to, bez \u010deho je d\u011blen\u00ed kan\u00e1lu na podnosn\u00e9 naprosto bezv\u00fdznamn\u00e9. Pro\u010d se sna\u017eit zkoumat r\u016fzn\u00e9 kousky spektra, kdy\u017e nebude mechanizmus, kter\u00fd by mohl donutit klienty nov\u00e9 s\u00edt\u011b Wi-Fi 6 poru\u0161it jedno z dosud neot\u0159esiteln\u00fdch pravidel a za\u010d\u00edt mluvit sou\u010dasn\u011b? A samoz\u0159ejm\u011b, takov\u00fd mechanizmus prost\u011b musel vzniknout \u2014 a sn\u00ed\u017eit vliv probl\u00e9mu \u201edlouh\u00e9\u201c doby ve srovn\u00e1n\u00ed s \u00fadaji o \u0159\u00edzen\u00ed. Jak? Je to velmi jednoduch\u00e9: a\u0165 se \u201epomal\u00e1\u201c \u010d\u00e1st \u0159\u00edzen\u00ed \u0161\u00ed\u0159\u00ed tak, jak tomu bylo d\u0159\u00edve, ale \u201erychlou\u201c \u010d\u00e1st, ve kter\u00e9 proch\u00e1zej\u00ed p\u0159\u00edmo \u00fadaje, budeme pos\u00edlat sou\u010dasn\u011b z n\u011bkolika (nebo na n\u011bkolik) za\u0159\u00edzen\u00ed na povel! Vypad\u00e1 to p\u0159ibli\u017en\u011b takto:<\/p>\n

      \"Nejd\u016fle\u017eit\u011bj\u0161\u00ed
      \n
      \nVypad\u00e1 to slo\u017eit\u011b, ale ve sv\u00e9 podstat\u011b se to vysv\u011btluje celkem snadno: p\u0159\u00edstupov\u00fd bod pomoc\u00ed speci\u00e1ln\u00edho r\u00e1mce, kter\u00fd je srozumiteln\u00fd v\u0161em (dokonce i za\u0159\u00edzen\u00ed, kter\u00e9 nejsou Wi-Fi 6!), oznamuje, \u017ee je p\u0159ipraven p\u0159ed\u00e1vat \u00fadaje sou\u010dasn\u011b STA1 a STA2. Proto\u017ee je \u201ehlavi\u010dka\u201c tohoto r\u00e1mce naprosto srozumiteln\u00e1 i t\u011bm opravdu velmi star\u00fdm klient\u016fm, dosp\u00edvaj\u00ed k spr\u00e1vn\u00e9mu z\u00e1v\u011bru, \u017ee \u00e9ter bude po ur\u010ditou dobu obsazen p\u0159ed\u00e1v\u00e1n\u00edm informac\u00ed ostatn\u00edm klient\u016fm s\u00edt\u011b, a za\u010d\u00ednaj\u00ed odpo\u010d\u00edt\u00e1vat \u010das do konce tohoto obdob\u00ed (jak tomu bylo v\u017edy ve Wi-Fi). A za\u0159\u00edzen\u00ed STA1 a STA2 ch\u00e1pou, \u017ee nyn\u00ed jim budou p\u0159ed\u00e1ny \u00fadaje u\u017e nov\u00fdm zp\u016fsobem, sou\u010dasn\u011b, ka\u017ed\u00e9mu na jeho kousku kan\u00e1lu, a odpov\u00eddaj\u00ed p\u0159\u00edstupov\u00e9mu bodu tak\u00e9 sou\u010dasn\u011b, a pot\u00e9 tak\u00e9 synchronn\u011b potvrzuj\u00ed p\u0159ijet\u00ed r\u00e1mce (ka\u017ed\u00fd se svou porc\u00ed dat!), a m\u00e9dium je op\u011bt uvoln\u011bno. \u201eZespodu nahoru\u201c to funguje p\u0159ibli\u017en\u011b stejn\u00fdm zp\u016fsobem:<\/p>\n

      \"Nejd\u016fle\u017eit\u011bj\u0161\u00ed
      \n
      \nHlavn\u00ed a n\u00e1padn\u00fd rozd\u00edl spo\u010d\u00edv\u00e1 v tom, \u017ee p\u0159\u00edstupov\u00fd bod v t\u00e9to situaci informuje stanic\u00edm schopn\u00fdm komunikovat sou\u010dasn\u011b, kdy maj\u00ed za\u010d\u00edt p\u0159enos, pomoc\u00ed speci\u00e1ln\u00edho r\u00e1mce, kter\u00fd se naz\u00fdv\u00e1 Trigger. To je v podstat\u011b nov\u00fd \"spou\u0161t\u011bc\u00ed mechanismus\" cel\u00e9ho syst\u00e9mu v\u00edcero soub\u011b\u017en\u00e9ho p\u0159\u00edstupu k prost\u0159ed\u00ed, kter\u00fd, podle m\u00e9ho skromn\u00e9ho n\u00e1zoru, p\u0159edstavuje jednu z nejd\u016fle\u017eit\u011bj\u0161\u00edch inovac\u00ed \"pod kapotou\" nov\u00e9ho standardu. Pr\u00e1v\u011b v n\u011bm klienti dost\u00e1vaj\u00ed \"rozvrh\", jak maj\u00ed sd\u00edlet jeden frekven\u010dn\u00ed kan\u00e1l; pr\u00e1v\u011b v n\u011bm klienti sou\u010dasn\u011b informuj\u00ed p\u0159\u00edstupov\u00fd bod, \u017ee obdr\u017eeli sv\u00e9 datov\u00e9 bal\u00ed\u010dky a dok\u00e1zali je zpracovat. V n\u011bm p\u0159\u00edstupov\u00fd bod upozor\u0148uje v\u0161echny, kte\u0159\u00ed mohou \"mluvit\" sou\u010dasn\u011b, na za\u010d\u00e1tek p\u0159enosu dat \u2014 v n\u011bm p\u0159\u00edstupov\u00fd bod tak\u00e9 spou\u0161t\u00ed odesl\u00e1n\u00ed po\u017eadovan\u00fdch dat. Nov\u00fd mechanismus Trigger frame v podstat\u011b umo\u017e\u0148uje sn\u00ed\u017eit nehospod\u00e1rn\u00e9 vyu\u017eit\u00ed obsazenosti \u00e9teru \u2014 a to tak \u00fa\u010dinn\u011b, jak jen mnoho klient\u016f m\u016f\u017ee vyu\u017e\u00edvat a spr\u00e1vn\u011b vn\u00edmat!<\/p>\n

      A nyn\u00ed formulujeme hlavn\u00ed teze, kter\u00e9 vypl\u00fdvaj\u00ed z cel\u00e9ho tohoto dlouh\u00e9ho vypr\u00e1v\u011bn\u00ed a zasluhuj\u00ed si TL;DR: <\/p>\n

        \n
      1. P\u0159\u00edstupov\u00e9 body nov\u00e9ho standardu 802.11ax, i kdy\u017e se op\u00edraj\u00ed pouze o jedno z mnoha nov\u00fdch prvk\u016f, za\u010dnou zvy\u0161ovat celkovou propustnost cel\u00e9 s\u00edt\u011b ji\u017e s m\u011bl p\u0159\u00edstup pomoc\u00ed u\u017eivatelsk\u00e9ho jm\u00e9na a hesla.<\/b> kompatibiln\u00edm klientsk\u00fdm za\u0159\u00edzen\u00edm! Jakmile se objev\u00ed alespo\u0148 dva klienti, kte\u0159\u00ed mohou komunikovat sou\u010dasn\u011b, tak za jinak stejn\u00fdch podm\u00ednek (nem\u00e1m \u017e\u00e1dn\u00fd d\u016fvod p\u0159edpokl\u00e1dat, \u017ee ovlada\u010de pro klientsk\u00e9 r\u00e1diov\u00e9 moduly budou ps\u00e1ny l\u00e9pe ne\u017e d\u0159\u00edve, co\u017e znamen\u00e1, \u017ee agregace \"u\u017eite\u010dn\u00fdch\" \u010d\u00e1st\u00ed r\u00e1mc\u016f a mnoho dal\u0161\u00edch funkc\u00ed z\u00e1visl\u00fdch na klientech st\u00e1le \"d\u00e1 t\u011bm pr\u016fm\u011brn\u00fdm zv\u011bdavc\u016fm\" nebude fungovat p\u0159\u00edli\u0161 dob\u0159e) ji\u017e ZV\u00dd\u0160\u00cd pr\u016fm\u011brnou propustnost. Tak\u017ee pokud zva\u017eujete novou Wi-Fi s\u00ed\u0165 \u2014 m\u00e1 smysl rovnou zv\u00e1\u017eit ty nejnov\u011bj\u0161\u00ed a nejlep\u0161\u00ed p\u0159\u00edstupov\u00e9 body, proto\u017ee i kdy\u017e nyn\u00ed pro n\u011b je\u0161t\u011b nen\u00ed p\u0159\u00edli\u0161 klient\u016f \u2014 tato situace dlouho nevydr\u017e\u00ed.<\/li>\n
      2. V\u0161echny triky a f\u00edgle, kter\u00e9 m\u00e1 dnes v arzen\u00e1lu dobr\u00fd bezdr\u00e1tov\u00fd in\u017een\u00fdr, z\u016fstanou je\u0161t\u011b dlouho aktu\u00e1ln\u00ed \u2014 p\u0159\u00edstupov\u00fd mechanismus se sice obnovil a naru\u0161il v\u00edce ne\u017e 20 let trvaj\u00edc\u00ed z\u00e1kladn\u00ed principy, ale st\u00e1le klade d\u016fraz na kompatibilitu. Po\u0159\u00e1d je pot\u0159eba od\u0159\u00edznout \"pomal\u00e9\" management rates (a st\u00e1le je pot\u0159eba ch\u00e1pat, pro\u010d a kdy), st\u00e1le je pot\u0159eba spr\u00e1vn\u011b pl\u00e1novat fyzickou \u00farove\u0148, proto\u017ee \u017e\u00e1dn\u00fd mechanismus na kan\u00e1lov\u00e9 \u00farovni nebude fungovat, pokud jsou na fyzick\u00e9 \u00farovni probl\u00e9my. Jen se objevila mo\u017enost d\u011blat je\u0161t\u011b l\u00e9pe<\/i>.<\/li>\n
      3. T\u00e9m\u011b\u0159 v\u0161echna rozhodnut\u00ed v Wi-Fi 6 p\u0159ij\u00edm\u00e1 p\u0159\u00edstupov\u00fd bod. Jak vid\u00edme, \u0159\u00edd\u00ed p\u0159\u00edstup klient\u016f k prost\u0159ed\u00ed, spojuje za\u0159\u00edzen\u00ed do \"obdob\u00ed\" simult\u00e1nn\u00edho provozu. Pokud se posuneme trochu d\u00e1l \u2014 pr\u00e1ce TWT je tak\u00e9 zcela na bedrech p\u0159\u00edstupov\u00e9ho bodu. Nyn\u00ed mus\u00ed AP nejen \"vys\u00edlat s\u00ed\u0165\" a uchov\u00e1vat provoz v priorit\u00e1ch, ale tak\u00e9 sledovat v\u0161echny klienty, pl\u00e1novat, jak je nejl\u00e9pe spojit na z\u00e1klad\u011b jejich propustnosti a pot\u0159eb v provozu, jejich bateri\u00ed a mnoha dal\u0161\u00edch faktor\u016f \u2014 tento proces naz\u00fdv\u00e1m \"orchestrace\". Algoritmy, podle kter\u00fdch p\u0159\u00edstupov\u00fd bod bude p\u0159ij\u00edmat v\u0161echny tyto rozhodnut\u00ed, nejsou regulov\u00e1ny, co\u017e znamen\u00e1, \u017ee skute\u010dn\u00e1 kvalita a strukturovan\u00fd p\u0159\u00edstup v\u00fdrobc\u016f se projev\u00ed pr\u00e1v\u011b v n\u00e1vrhu algoritm\u016f orchestrace. \u010c\u00edm p\u0159esn\u011bji budou p\u0159\u00edstupov\u00e9 body p\u0159edpov\u00eddat pot\u0159eby klient\u016f, t\u00edm l\u00e9pe a rovnom\u011brn\u011bji je budou moci spojovat do skupin v\u00edcero provoz\u016f \u2014 t\u00edm p\u00e1dem t\u00edm efektivn\u011bji budou vyu\u017e\u00edv\u00e1ny prost\u0159edky vzduchu a t\u00edm vy\u0161\u0161\u00ed bude kone\u010dn\u00e1 propustnost takov\u00e9ho p\u0159\u00edstupov\u00e9ho bodu. Algoritmus \u2014 posledn\u00ed hranice!<\/li>\n
      4. P\u0159echod z Wi-Fi 5 na Wi-Fi 6 je v podstat\u011b a d\u016fle\u017eitosti tak revolu\u010dn\u00ed, jako p\u0159echod z 802.11g na 802.11n. Tehdy jsme dostali multi-streaming a agregaci \u201eu\u017eite\u010dn\u00e9ho zat\u00ed\u017een\u00ed\u201c \u2014 nyn\u00ed z\u00edsk\u00e1v\u00e1me sou\u010dasn\u00fd p\u0159\u00edstup k m\u00e9diu a kone\u010dn\u011b funguj\u00edc\u00ed MU-MIMO a Beamforming (za prv\u00e9, jak v\u00edme, to je t\u00e9m\u011b\u0159 to sam\u00e9; za druh\u00e9, diskuse \u201epro\u010d MU-MIMO v 802.11ac vymysleli, ale nedok\u00e1zali ho donutit fungovat\u201c \u2014 to je t\u00e9ma na velk\u00fd samostatn\u00fd \u010dl\u00e1nek \ud83d\ude42 ). A 802.11n, i Wi-Fi 6 pracuj\u00ed v obou p\u00e1smech (2,4 GHz a 5 GHz), na rozd\u00edl od \u201emezi\u201c p\u0159edch\u016fdc\u016f \u2014 skute\u010dn\u011b, \u201e\u0161est je nov\u00e9 \u010dty\u0159i\u201c!<\/li>\n<\/ol>\n

        <\/p>\n

        N\u011bco o p\u016fvodu tohoto \u010dl\u00e1nku<\/b>
        \n \u010cl\u00e1nek byl naps\u00e1n pro sout\u011b\u017e, kterou po\u0159\u00e1dala spole\u010dnost Huawei (p\u016fvodn\u011b byl publikov\u00e1n         tady<\/a><\/noindex>). V mnoha ohledech jsem se p\u0159i jeho psan\u00ed op\u00edral o svou vlastn\u00ed prezentaci na konferenci \u201eBezdr\u00e1tov\u00e9\u201c, kter\u00e1 se konala v roce 2019 v Petrohradu (nahr\u00e1vku vystoupen\u00ed m\u016f\u017eete shl\u00e9dnout na YouTube<\/a><\/noindex>, jen m\u011bjte na pam\u011bti \u2014 zvuk tam, abych tak \u0159ekl, nen\u00ed zrovna skv\u011bl\u00fd, navzdory petrohradsk\u00e9mu p\u016fvodu videa!).
        \n
        Zdroj:         habr.com<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

        \u041f\u0440\u0438\u0432\u0435\u0442. \u0415\u0441\u043b\u0438 \u0432\u0435\u0440\u0438\u0442\u044c \u0442\u0435\u043e\u0440\u0438\u0438 \u043f\u0440\u043e\u0441\u0442\u043e\u0442\u044b \u042d\u0439\u043d\u0448\u0442\u0435\u0439\u043d\u0430, \u0433\u043b\u0430\u0432\u043d\u044b\u0439 \u043f\u043e\u043a\u0430\u0437\u0430\u0442\u0435\u043b\u044c \u043f\u043e\u043d\u0438\u043c\u0430\u043d\u0438\u044f \u043f\u0440\u0435\u0434\u043c\u0435\u0442\u0430 \u2014 \u044d\u0442\u043e \u0441\u043f\u043e\u0441\u043e\u0431\u043d\u043e\u0441\u0442\u044c \u043c\u0430\u043a\u0441\u0438\u043c\u0430\u043b\u044c\u043d\u043e \u043f\u0440\u043e\u0441\u0442\u043e \u0435\u0433\u043e \u043e\u0431\u044a\u044f\u0441\u043d\u0438\u0442\u044c, \u0442\u043e \u0438 \u0432 \u044d\u0442\u043e\u043c \u043f\u043e\u0441\u0442\u0435 \u044f \u043f\u043e\u0441\u0442\u0430\u0440\u0430\u044e\u0441\u044c \u043c\u0430\u043a\u0441\u0438\u043c\u0430\u043b\u044c\u043d\u043e \u043f\u0440\u043e\u0441\u0442\u043e \u0438 \u043f\u043e\u0434\u0440\u043e\u0431\u043d\u043e \u043e\u0431\u044a\u044f\u0441\u043d\u0438\u0442\u044c \u0434\u0435\u0439\u0441\u0442\u0432\u0438\u0435 \u0432\u0441\u0435\u0433\u043e \u043e\u0434\u043d\u043e\u0439 \u0434\u0435\u0442\u0430\u043b\u0438 \u043d\u043e\u0432\u043e\u0433\u043e \u0441\u0442\u0430\u043d\u0434\u0430\u0440\u0442\u0430, \u043a\u043e\u0442\u043e\u0440\u0443\u044e \u043f\u043e\u0447\u0435\u043c\u0443-\u0442\u043e \u0434\u0430\u0436\u0435 Wi-Fi Alliance \u0441\u0447\u0438\u0442\u0430\u0435\u0442 \u043d\u0435\u0434\u043e\u0441\u0442\u043e\u0439\u043d\u043e\u0439 \u0443\u043f\u043e\u043c\u0438\u043d\u0430\u043d\u0438\u044f \u0432 \u0438\u043d\u0444\u043e\u0433\u0440\u0430\u0444\u0438\u043a\u0435 \u043e \u043d\u043e\u0432\u044b\u0445 \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044f\u0445 Wi-Fi 6, \u0445\u043e\u0442\u044f \u043e\u043d\u0430, \u043a\u0430\u043a \u043c\u044b \u0441\u043a\u043e\u0440\u043e […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":84591,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[688],"tags":[],"class_list":["post-84590","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-administrirovanie"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47Nejd\u016fle\u017eit\u011bj\u0161\u00ed v Wi-Fi 6. Ne, v\u00e1\u017en\u011b | ProHoster","description":"Ahoj. Pokud v\u011b\u0159it Einsteinov\u011b teorii jednoduchosti, hlavn\u00edm ukazatelem pochopen\u00ed ur\u010dit\u00e9ho t\u00e9matu je schopnost maxim\u00e1ln\u011b jednodu\u0161e ho vysv\u011btlit, tak i v tomto p\u0159\u00edsp\u011bvku se budu sna\u017eit maxim\u00e1ln\u011b jednodu\u0161e a podrobn\u011b vysv\u011btlit.","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/administrirovanie\/samoe-glavnoe-v-wi-fi-6-net-seryozno","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"cs_CZ","og:site_name":"ProHoster | \u041a\u0443\u043f\u0438\u0442\u044c \u043d\u0430\u0434\u0435\u0436\u043d\u044b\u0439 \u0445\u043e\u0441\u0442\u0438\u043d\u0433 \u0434\u043b\u044f \u0441\u0430\u0439\u0442\u043e\u0432 \u0441 \u0437\u0430\u0449\u0438\u0442\u043e\u0439 \u043e\u0442 DDoS, VPS VDS \u0441\u0435\u0440\u0432\u0435\u0440\u044b","og:type":"article","og:title":"\ud83e\udd47\u0421\u0430\u043c\u043e\u0435 \u0433\u043b\u0430\u0432\u043d\u043e\u0435 \u0432 Wi-Fi 6. \u041d\u0435\u0442, \u0441\u0435\u0440\u044c\u0451\u0437\u043d\u043e | ProHoster","og:description":"\u041f\u0440\u0438\u0432\u0435\u0442. \u0415\u0441\u043b\u0438 \u0432\u0435\u0440\u0438\u0442\u044c \u0442\u0435\u043e\u0440\u0438\u0438 \u043f\u0440\u043e\u0441\u0442\u043e\u0442\u044b \u042d\u0439\u043d\u0448\u0442\u0435\u0439\u043d\u0430, \u0433\u043b\u0430\u0432\u043d\u044b\u0439 \u043f\u043e\u043a\u0430\u0437\u0430\u0442\u0435\u043b\u044c \u043f\u043e\u043d\u0438\u043c\u0430\u043d\u0438\u044f \u043f\u0440\u0435\u0434\u043c\u0435\u0442\u0430 \u2014 \u044d\u0442\u043e \u0441\u043f\u043e\u0441\u043e\u0431\u043d\u043e\u0441\u0442\u044c \u043c\u0430\u043a\u0441\u0438\u043c\u0430\u043b\u044c\u043d\u043e \u043f\u0440\u043e\u0441\u0442\u043e \u0435\u0433\u043e \u043e\u0431\u044a\u044f\u0441\u043d\u0438\u0442\u044c, \u0442\u043e \u0438 \u0432 \u044d\u0442\u043e\u043c \u043f\u043e\u0441\u0442\u0435 \u044f \u043f\u043e\u0441\u0442\u0430\u0440\u0430\u044e\u0441\u044c \u043c\u0430\u043a\u0441\u0438\u043c\u0430\u043b\u044c\u043d\u043e \u043f\u0440\u043e\u0441\u0442\u043e \u0438 \u043f\u043e\u0434\u0440\u043e\u0431\u043d\u043e \u043e\u0431\u044a\u044f\u0441\u043d\u0438\u0442\u044c.","og:url":"https:\/\/prohoster.info\/cs\/blog\/administrirovanie\/samoe-glavnoe-v-wi-fi-6-net-seryozno","og:image":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:secure_url":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:width":350,"og:image:height":350,"article:published_time":"2020-06-08T23:42:40+00:00","article:modified_time":"2020-06-08T23:42:40+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"84590","title":null,"description":null,"keywords":null,"keyphrases":null,"primary_term":null,"canonical_url":null,"og_title":null,"og_description":null,"og_object_type":"default","og_image_type":"default","og_image_url":null,"og_image_width":null,"og_image_height":null,"og_image_custom_url":null,"og_image_custom_fields":null,"og_video":null,"og_custom_url":null,"og_article_section":null,"og_article_tags":null,"twitter_use_og":false,"twitter_card":"default","twitter_image_type":"default","twitter_image_url":null,"twitter_image_custom_url":null,"twitter_image_custom_fields":null,"twitter_title":null,"twitter_description":null,"schema":{"blockGraphs":[],"customGraphs":[],"default":{"data":{"Article":[],"Course":[],"Dataset":[],"FAQPage":[],"Movie":[],"Person":[],"Product":[],"ProductReview":[],"Car":[],"Recipe":[],"Service":[],"SoftwareApplication":[],"WebPage":[]},"graphName":"","isEnabled":true},"graphs":[]},"schema_type":null,"schema_type_options":null,"pillar_content":false,"robots_default":true,"robots_noindex":false,"robots_noarchive":false,"robots_nosnippet":false,"robots_nofollow":false,"robots_noimageindex":false,"robots_noodp":false,"robots_notranslate":false,"robots_max_snippet":null,"robots_max_videopreview":null,"robots_max_imagepreview":"large","priority":null,"frequency":null,"local_seo":null,"seo_analyzer_scan_date":null,"breadcrumb_settings":null,"limit_modified_date":false,"reviewed_by":null,"ai":null,"created":"2021-02-28 14:54:33","updated":"2022-10-01 21:53:56","focus_keyword":null,"additional_keywords":null,"truseo_locale":null},"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts\/84590","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/comments?post=84590"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts\/84590\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/media\/84591"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/media?parent=84590"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/categories?post=84590"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/tags?post=84590"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}