{"id":38332,"date":"2019-10-31T22:23:01","date_gmt":"2019-10-31T19:23:01","guid":{"rendered":"https:\/\/prohoster.info\/blog\/trening-cisco-200-125-ccna-v3-0-den-44-vvedenie-v-ospf\/"},"modified":"2019-10-31T22:23:01","modified_gmt":"2019-10-31T19:23:01","slug":"trening-cisco-200-125-ccna-v3-0-den-44-vvedenie-v-ospf","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sk\/blog\/administrirovanie\/trening-cisco-200-125-ccna-v3-0-den-44-vvedenie-v-ospf","title":{"rendered":"Tr\u00e9ning Cisco 200-125 CCNA v3.0. De\u0148 44. \u00davod do OSPF","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Dnes za\u010dneme \u0161t\u00fadium smerovania pomocou protokolu OSPF. T\u00e1to t\u00e9ma, rovnako ako aj preberanie protokolu EIGRP, je k\u013e\u00fa\u010dov\u00e1 v celom kurze CCNA. Ako vid\u00edte, sekcia 2.4 sa naz\u00fdva \u201eNastavenie, overenie a odstra\u0148ovanie probl\u00e9mov s jednotnou a viacer\u00fdmi z\u00f3nami OSPFv2 pre protokol IPv4 (okrem autentifik\u00e1cie, filtr\u00e1cie, ru\u010dn\u00e9ho sumarizovania tr\u00e1s, redistrib\u00facie, m\u0155tvej z\u00f3ny, virtu\u00e1lnej siete a LSA)\". <\/p>\n

\"Tr\u00e9ning
\n
\nT\u00e9ma OSPF je dos\u0165 rozsiahla, preto zaberie 2, mo\u017eno aj 3 video lekcie. Dne\u0161n\u00e1 lekcia bude zameran\u00e1 na teoretick\u00fa str\u00e1nku, poviem v\u00e1m, \u010do predstavuje tento protokol v \u0161ir\u0161\u00edch s\u00favislostiach a ako funguje. V nasleduj\u00facom videu prejdeme do re\u017eimu konfigur\u00e1cie OSPF s pomocou Packet Tracer.<\/a><\/noindex><\/p>\n

Tak\u017ee v tejto lekcii sa pozrieme na tri veci: \u010do je OSPF, ako funguje a \u010do s\u00fa z\u00f3ny OSPF. V predch\u00e1dzaj\u00facej lekcii sme sa bavili o tom, \u017ee OSPF je protokol routovania typu Link State, sk\u00fama komunika\u010dn\u00e9 kan\u00e1ly medzi smerova\u010dmi a prij\u00edma rozhodnutia na z\u00e1klade r\u00fdchlosti t\u00fdchto kan\u00e1lov. Dlh\u00fd kan\u00e1l s vy\u0161\u0161ou r\u00fdchlos\u0165ou, teda s v\u00e4\u010d\u0161ou \u0161\u00edrkou p\u00e1sma, m\u00e1 prednos\u0165 pred kr\u00e1tkym kan\u00e1lom s men\u0161ou \u0161\u00edrkou p\u00e1sma.<\/p>\n

Protokol RIP, ktor\u00fd je vzdialene vektorov\u00fd, si vyberie cestu v jednom skoku, aj ke\u010f tento kan\u00e1l m\u00e1 n\u00edzku r\u00fdchlos\u0165, zatia\u013e \u010do protokol OSPF si zvol\u00ed dlh\u0161iu trasu z viacer\u00fdch skokov, ak celkov\u00e1 r\u00fdchlos\u0165 na tejto trase prevy\u0161uje r\u00fdchlos\u0165 prev\u00e1dzky na kr\u00e1tkej trase. <\/p>\n

\"Tr\u00e9ning
\n
\nNesk\u00f4r si prejdeme algoritmus rozhodovania, zatia\u013e si mus\u00edte zapam\u00e4ta\u0165, \u017ee OSPF je protokol stavu kan\u00e1lov typu Link State. Tento otvoren\u00fd \u0161tandard bol vytvoren\u00fd v roku 1988, tak\u017ee ho mohli vyu\u017ei\u0165 v\u0161etci v\u00fdrobcovia sie\u0165ov\u00e9ho vybavenia a ak\u00fdko\u013evek poskytovate\u013e siete. Preto je OSPF ove\u013ea popul\u00e1rnej\u0161ie ako EIGRP. <\/p>\n

Protokol OSPF verzia 2 podporuje len protokol IPv4, a o rok nesk\u00f4r, v roku 1989, v\u00fdvoj\u00e1ri ozn\u00e1mili vydanie 3. verzie, ktor\u00e1 podporuje IPv6. Av\u0161ak plne funk\u010dn\u00e1 tretia verzia OSPF pre IPv6 sa objavila a\u017e v roku 2008. Pre\u010do bol vybran\u00fd pr\u00e1ve OSPF? V poslednej lekcii sme sa dozvedeli, \u017ee tento protokol vn\u00fatorn\u00e9ho br\u00e1ny dosahuje konvergenciu tr\u00e1s ove\u013ea r\u00fdchlej\u0161ie ako RIP. Je to beztriedny protokol. <\/p>\n

Ak si pam\u00e4t\u00e1te, RIP je klasov\u00fd protokol, to znamen\u00e1, \u017ee neodosiela inform\u00e1cie o maske podsiete, a ak sa mu objav\u00ed IP adresa triedy A\/24, neprijme ju. Napr\u00edklad, ak mu predstav\u00edte IP adresu 10.1.1.0\/24, prijme ju ako sie\u0165 10.0.0.0, preto\u017ee nerozumie, ke\u010f sa sie\u0165 del\u00ed na podsiete s pou\u017eit\u00edm viac ako jednej masky podsiete.
\nOSPF je zabezpe\u010den\u00fd protokol. Napr\u00edklad, ak si dva smerova\u010de vymie\u0148aj\u00fa inform\u00e1cie OSPF, m\u00f4\u017eete nastavi\u0165 autentifik\u00e1ciu tak, \u017ee zdie\u013eanie inform\u00e1ci\u00ed so susedn\u00fdm smerova\u010dom bude mo\u017en\u00e9 a\u017e po zadan\u00ed hesla. Ako sme u\u017e povedali, je to otvoren\u00fd \u0161tandard, preto OSPF pou\u017e\u00edvaj\u00fa mnoh\u00ed v\u00fdrobcovia sie\u0165ov\u00e9ho vybavenia.<\/p>\n

Vo glob\u00e1lnom zmysle OSPF predstavuje mechanizmus v\u00fdmeny ozn\u00e1men\u00ed o stave odkazu (Link State Advertisement), alebo LSA. Spr\u00e1vy LSA generuje smerova\u010d a obsahuj\u00fa mno\u017estvo inform\u00e1ci\u00ed: jedine\u010dn\u00fd identifik\u00e1tor smerova\u010da (router-id), \u00fadaje o sie\u0165ach, zn\u00e1mymi smerova\u010dom, \u00fadaje o ich n\u00e1kladoch a tak \u010falej. V\u0161etky tieto inform\u00e1cie s\u00fa potrebn\u00e9 smerova\u010du na prijatie rozhodnut\u00ed o smerovan\u00ed. <\/p>\n

\"Tr\u00e9ning
\n
\nSmerova\u010d R3 posiela svoju inform\u00e1ciu LSA smerova\u010du R5, a smerova\u010d R5 zdie\u013ea svoju LSA inform\u00e1ciu s R3. Tieto LSA predstavuj\u00fa \u0161trukt\u00faru \u00fadajov, ktor\u00e1 tvor\u00ed datab\u00e1zu stavu odkazov (Link State Data Base, alebo LSDB). Smerova\u010d zhroma\u017e\u010fuje v\u0161etky prijat\u00e9 LSA a umiest\u0148uje ich do svojej LSDB. Po vytvoren\u00ed svojich datab\u00e1z si oba smerova\u010de vymie\u0148aj\u00fa spr\u00e1vy Hello, ktor\u00e9 sl\u00fa\u017eia na zistenie susedov, a za\u010d\u00ednaj\u00fa postup porovnania svojich LSDB.<\/p>\n

Smerova\u010d R3 posiela smerova\u010du R5 spr\u00e1vu DBD, alebo \"popis datab\u00e1zy\", a R5 posiela svoje DBD smerova\u010du R3. Tieto spr\u00e1vy obsahuj\u00fa indexy LSA, ktor\u00e9 s\u00fa v datab\u00e1zach ka\u017ed\u00e9ho smerova\u010da. Po prijat\u00ed DBD smerova\u010d R3 posiela po\u017eiadavku na stav siete (LSR) smerova\u010du R5, v ktorej hovor\u00ed: \"u\u017e m\u00e1m spr\u00e1vy 3, 4 a 9, tak\u017ee mi po\u0161lite len 5 a 7\". <\/p>\n

R5 postupuje rovnako a oznamuje tret\u00edmu routeru: \u201em\u00e1m inform\u00e1cie 3, 4 a 9, tak\u017ee mi po\u0161lite 1 a 2\u201c. Po prijat\u00ed po\u017eiadaviek LSR routery posielaj\u00fa sp\u00e4\u0165 pakety aktualiz\u00e1cie stavu siete LSU, to znamen\u00e1, \u017ee v odpovedi na svoj LSR tret\u00ed router dost\u00e1va LSU od routera R5. Po aktualiz\u00e1cii svojich datab\u00e1z bud\u00fa v\u0161etky routery, aj ke\u010f ich m\u00e1te 100, ma\u0165 rovnak\u00e9 datab\u00e1zy LSDB. Akon\u00e1hle s\u00fa v routeroch vytvoren\u00e9 datab\u00e1zy LSDB, ka\u017ed\u00fd z nich bude vedie\u0165 o celkovej sieti. Protokol OSPF vyu\u017e\u00edva algoritmus Shortest Path First na vytvorenie smerovacej tabu\u013eky, preto je najd\u00f4le\u017eitej\u0161ou podmienkou jeho spr\u00e1vnej funkcie synchroniz\u00e1cia LSDB v\u0161etk\u00fdch zariaden\u00ed v sieti. <\/p>\n

\"Tr\u00e9ning
\n
\nNa uvedenom sch\u00e9me je umiestnen\u00fdch 9 routerov, z ktor\u00fdch ka\u017ed\u00fd si vymie\u0148a spr\u00e1vy LSR, LSU a tak \u010falej so susedmi. V\u0161etky s\u00fa navz\u00e1jom prepojen\u00e9 prostredn\u00edctvom p2p, alebo \u201epoint-to-point\u201c rozhran\u00ed, ktor\u00e9 podporuj\u00fa protokol OSPF, a navz\u00e1jom interaguj\u00fa s cie\u013eom vytvori\u0165 rovnak\u00e9 LSDB. <\/p>\n

\"Tr\u00e9ning
\n
\nAkon\u00e1hle bud\u00fa datab\u00e1zy synchronizovan\u00e9, ka\u017ed\u00fd router pomocou algoritmu na najkrat\u0161iu trasu vytvor\u00ed svoju smerovaciu tabu\u013eku. Tieto tabu\u013eky bud\u00fa r\u00f4zne pre r\u00f4zne routery. To znamen\u00e1, \u017ee v\u0161etky routery pou\u017e\u00edvaj\u00fa rovnak\u00e9 LSDB, ale vytv\u00e1raj\u00fa smerovacie tabu\u013eky na z\u00e1klade svojich vlastn\u00fdch \u00favah o najkrat\u0161\u00edch tras\u00e1ch. Na vyu\u017eitie tohto algoritmu potrebuje OSPF pravideln\u00fa aktualiz\u00e1ciu datab\u00e1zy LSDB. <\/p>\n

Tak\u017ee pre vlastn\u00fa funk\u010dnos\u0165 OSPF mus\u00ed najprv splni\u0165 3 podmienky: n\u00e1js\u0165 susedov, vytvori\u0165 a aktualizova\u0165 LSDB a vytvori\u0165 smerovaciu tabu\u013eku. Na splnenie prvej podmienky m\u00f4\u017ee sie\u0165ov\u00e9mu administr\u00e1torovi by\u0165 potrebn\u00e9 ru\u010dne nastavi\u0165 router-id, \u010dasov\u00e9 intervaly alebo wildcard masku. V nasleduj\u00facom videu sa pozrieme na konfigur\u00e1ciu zariadenia pre pr\u00e1cu s OSPF, zatia\u013e \u010do by ste mali vedie\u0165, \u017ee tento protokol pou\u017e\u00edva sp\u00e4tn\u00fa masku, a ak sa nezhoduje, ak sa va\u0161e podsiete nezhoduj\u00fa, alebo ak sa nezhoduje autentifik\u00e1cia, nie je mo\u017en\u00e9 vytvori\u0165 susedstvo routerov. Preto pri rie\u0161en\u00ed probl\u00e9mov s fungovan\u00edm OSPF mus\u00edte zisti\u0165, pre\u010do sa tieto susedstv\u00e1 nevytv\u00e1raj\u00fa, t.j. overi\u0165 zhodu vy\u0161\u0161ie uveden\u00fdch parametrov.<\/p>\n

Ako administr\u00e1tor siete sa nez\u00fa\u010dast\u0148ujete na procese vytv\u00e1rania LSDB. Aktualiz\u00e1cia datab\u00e1z prebieha automaticky po vytvoren\u00ed susedstva routerov, rovnako ako aj zostavenie smerovac\u00edch tabuliek. To v\u0161etko vykon\u00e1va samo zariadenie nastaven\u00e9 na pr\u00e1cu s protokolom OSPF.
\nPozrime sa na pr\u00edklad. M\u00e1me 2 routre, ktor\u00fdm som pre zjednodu\u0161enie priradil identifik\u00e1tory RID 1.1.1.1 a 2.2.2.2. Akon\u00e1hle ich prepoj\u00edme, kan\u00e1l link sa okam\u017eite dostane do stavu up, preto\u017ee som tieto routre najprv nastavil na pr\u00e1cu s OSPF. Akon\u00e1hle sa vytvor\u00ed komunika\u010dn\u00fd kan\u00e1l, router A okam\u017eite po\u0161le druh\u00e9mu paket Hello. Tento bal\u00edk obsahuje inform\u00e1cie o tom, \u017ee tento router e\u0161te nikoho na tomto kan\u00e1li \u201enevidel\u201c, preto\u017ee odosiela Hello prv\u00fdkr\u00e1t, ako aj jeho vlastn\u00fd identifik\u00e1tor, \u00fadaje o pripojenej sieti a \u010fal\u0161ie inform\u00e1cie, ktor\u00e9 m\u00f4\u017ee zdie\u013ea\u0165 so susedom. <\/p>\n

\"Tr\u00e9ning
\n
\nAkon\u00e1hle router B prijme tento paket, povie: \u201evid\u00edm, \u017ee na tomto komunika\u010dnom kan\u00e1li je potenci\u00e1lny kandid\u00e1t na susedstvo prostredn\u00edctvom protokolu OSPF\u201c a prejde do stavu inicializ\u00e1cie Init state. Paket Hello nie je unicastov\u00e1 alebo broadcastov\u00e1 spr\u00e1va, je to multicastov\u00fd paket, ktor\u00fd sa odosiela na multicastov\u00fa OSPF IP-adresu 224.0.0.5. Niektor\u00ed \u013eudia sa p\u00fdtaj\u00fa, ak\u00e1 je maska podsiete pre multicast. Faktom je, \u017ee multicast nem\u00e1 masku podsiete, \u0161\u00edri sa ako r\u00e1diov\u00fd sign\u00e1l, ktor\u00fd po\u010duj\u00fa v\u0161etky zariadenia nastaven\u00e9 na jeho frekvenciu. Napr\u00edklad, ak chcete po\u010du\u0165 FM r\u00e1dio vysielaj\u00face na frekvencii 91,0, nalad\u00edte svoj r\u00e1dioprij\u00edma\u010d na t\u00fato frekvenciu. <\/p>\n

Podobne je router B nastaven\u00fd na prij\u00edmanie spr\u00e1v pre multicastov\u00fa adresu 224.0.0.5. Po\u010d\u00favaj\u00fac tento kan\u00e1l, prij\u00edma paket Hello, ktor\u00fd odoslal router A, a odpoved\u00e1 mu svojou spr\u00e1vou. <\/p>\n

\"Tr\u00e9ning
\n
\nSusedstvo sa m\u00f4\u017ee ustanovi\u0165 iba v pr\u00edpade, \u017ee odpove\u010f B vyhovuje s\u00faboru krit\u00e9ri\u00ed. Prv\u00fdm krit\u00e9riom je, \u017ee frekvencia odosielania spr\u00e1v Hello a \u010dasov\u00fd interval na \u010dakanie na odpove\u010f na t\u00fato spr\u00e1vu Dead Interval musia by\u0165 rovnak\u00e9 pre oba routre. Zvy\u010dajne je Dead Interval rovn\u00fd nieko\u013ek\u00fdm hodnot\u00e1m \u010dasova\u010da Hello. Tak\u017ee ak je Hello Timer routera A 10 s a router B mu po\u0161le spr\u00e1vu po 30 s, pri\u010dom Dead Interval je 20 s, susedstvo sa neuskuto\u010dn\u00ed. <\/p>\n

Druh\u00fd krit\u00e9rium \u2013 oba smerova\u010de musia pou\u017e\u00edva\u0165 rovnak\u00fd typ autentifik\u00e1cie. Zodpovedaj\u00faco, autentifika\u010dn\u00e9 hesl\u00e1 musia by\u0165 tie\u017e rovnak\u00e9. <\/p>\n

Tret\u00ed krit\u00e9rium \u2013 zhoda identifik\u00e1torov z\u00f3ny Arial ID, \u0161tvrt\u00fd \u2013 zhoda d\u013a\u017eky prefiksu siete. Ak smerova\u010d A oznamuje prefiks \/24, tak smerova\u010d B mus\u00ed ma\u0165 tie\u017e prefiks siete \/24. V nasleduj\u00facom videu sa na to pozrieme podrobnej\u0161ie, zatia\u013e si v\u0161imnite, \u017ee to nie je maska podsiete, tu smerova\u010de pou\u017e\u00edvaj\u00fa obr\u00e1ten\u00fa masku Wildcard mask. A samozrejme, flagy stub z\u00f3ny Stub area musia by\u0165 tie\u017e zhoden\u00e9, ak sa smerova\u010de nach\u00e1dzaj\u00fa v tejto z\u00f3ne. <\/p>\n

Po overen\u00ed t\u00fdchto krit\u00e9ri\u00ed, v pr\u00edpade ich zhody, smerova\u010d B posiela smerova\u010du A svoj Hello paket. Na rozdiel od spr\u00e1vy A, smerova\u010d B oznamuje, \u017ee videl smerova\u010d A a predstavuje sa. <\/p>\n

\"Tr\u00e9ning
\n
\nNa t\u00fato spr\u00e1vu smerova\u010d A op\u00e4\u0165 posiela Hello smerova\u010du B, v ktorom potvrdzuje, \u017ee tie\u017e videl smerova\u010d B, komunika\u010dn\u00fd kan\u00e1l medzi nimi pozost\u00e1va z zariaden\u00ed 1.1.1.1 a 2.2.2.2, pri\u010dom on s\u00e1m je zariaden\u00edm 1.1.1.1. Toto je ve\u013emi d\u00f4le\u017eit\u00e1 f\u00e1za nadviazania susedstva. V tomto pr\u00edpade sa pou\u017e\u00edva obojsmern\u00e9 spojenie 2-WAY, ale \u010do sa stane, ak m\u00e1me switch s distribuovanou sie\u0165ou \u0161tyroch smerova\u010dov? V takejto \u201ezdielanej\u201c prostred\u00ed mus\u00ed jeden zo smerova\u010dov hra\u0165 \u00falohu vyhraden\u00e9ho smerova\u010da Designated router D.R, a druh\u00fd \u2013 z\u00e1lo\u017en\u00e9ho vyhraden\u00e9ho smerova\u010da Backup designated router B.D.R.<\/p>\n

\"Tr\u00e9ning
\n
\nKa\u017ed\u00e9 z t\u00fdchto zariaden\u00ed vytvor\u00ed Full connection, alebo stav plnej susednosti, nesk\u00f4r si objasn\u00edme, \u010do to znamen\u00e1, av\u0161ak spojenie tohto typu sa vytvor\u00ed iba s D.R. a B.D.R, navz\u00e1jom sa dva ni\u017e\u0161ie smerova\u010de D a B predsa bud\u00fa komunikova\u0165 pod\u013ea sch\u00e9my obojsmern\u00e9ho spojenia \u201epoint-to-point.\u201c <\/p>\n

To znamen\u00e1, \u017ee s D.R. a B.D.R v\u0161etky smerova\u010de vytv\u00e1raj\u00fa vz\u0165ah plnej susednosti, a navz\u00e1jom \u2013 spojenie typu point-to-point. Toto je ve\u013emi d\u00f4le\u017eit\u00e9, preto\u017ee pri obojsmernom spojen\u00ed susedn\u00fdch zariaden\u00ed musia v\u0161etky parametre paketu Hello s\u00fahlasi\u0165. V na\u0161om pr\u00edpade v\u0161etko s\u00fahlas\u00ed, preto zariadenia bez probl\u00e9mov vytv\u00e1raj\u00fa susedstvo. <\/p>\n

Akon sa obojstrann\u00e9 spojenie nadvia\u017ee, router A odo\u0161le routeru B paket Database Description, alebo \"opis datab\u00e1zy\", a prejde do stavu ExStart \u2013 za\u010diatok v\u00fdmeny, alebo \u010dakaj\u00fa na na\u010d\u00edtanie. Database Descriptor predstavuje inform\u00e1cie, podobn\u00e9 obsahu knihy \u2013 je to zoznam v\u0161etk\u00e9ho, \u010do sa nach\u00e1dza v datab\u00e1ze smerovania. V odpovedi router B po\u0161le svoje op\u00edsanie datab\u00e1zy routeru A a prejde do stavu v\u00fdmeny \u00fadajov o kan\u00e1loch Exchange. Ak v stave Exchange router zist\u00ed, \u017ee v jeho datab\u00e1ze ch\u00fdbaj\u00fa nejak\u00e9 inform\u00e1cie, prejde do stavu na\u010d\u00edtania LOADING a za\u010dne si vymie\u0148a\u0165 s partnerom spr\u00e1vy LSR, LSU a LSA.<\/p>\n

\"Tr\u00e9ning
\n
\nTak\u017ee router A po\u0161le susedovi LSR, ktor\u00fd mu odpovie paketom LSU, na \u010do router A odpovie routeru B spr\u00e1vou LSA. T\u00e1to v\u00fdmena sa uskuto\u010dn\u00ed to\u013ekokr\u00e1t, ko\u013ekokr\u00e1t si zariadenia bud\u00fa chcie\u0165 vymeni\u0165 spr\u00e1vy LSA. Stav LOADING znamen\u00e1, \u017ee \u00fapln\u00e1 aktualiz\u00e1cia datab\u00e1zy LSA sa e\u0161te neuskuto\u010dnila. Po na\u010d\u00edtan\u00ed v\u0161etk\u00fdch \u00fadajov prejd\u00fa obe zariadenia do stavu plnej susednosti FULL.<\/p>\n

Poznamen\u00e1vam, \u017ee pri obojstrannom spojen\u00ed zariadenia s\u00fa v stave susedstva, a stav plnej susednosti je mo\u017en\u00fd len medzi smerova\u010dmi D.R. a B.D.R. To znamen\u00e1, \u017ee ka\u017ed\u00fd router informuje D.R. o zmen\u00e1ch v sieti a v\u0161etky routery sa o t\u00fdchto zmen\u00e1ch dozvedaj\u00fa od D.R.<\/p>\n

V\u00fdber D.R. a B.D.R je d\u00f4le\u017eit\u00e1 ot\u00e1zka. Pozrime sa, ako prebieha v\u00fdber D.R. v be\u017enom prostred\u00ed. Predpokladajme, \u017ee v na\u0161ej sch\u00e9me s\u00fa tri smerova\u010de a prep\u00edna\u010d. Najprv zariadenia OSPF porovnaj\u00fa priority v Hello spr\u00e1vach, potom porovnaj\u00fa Router ID. <\/p>\n

Zariadenie s najvy\u0161\u0161ou priority sa st\u00e1va D.R. Ak sa priority dvoch zariaden\u00ed zhoduj\u00fa, z t\u00fdchto dvoch sa vyberie zariadenie s najvy\u0161\u0161\u00edm Router ID, ktor\u00e9 sa stane D.R.<\/p>\n

Z\u00e1lo\u017en\u00fdm vyhraden\u00fdm smerova\u010dom B.D.R sa st\u00e1va zariadenie so druhou najv\u00fdznamnej\u0161ou prioritou alebo so druh\u00fdm najv\u00fdznamnej\u0161\u00edm Router ID. Ak D.R. zlyh\u00e1, okam\u017eite ho nahrad\u00ed B.D.R. Ten za\u010dne plni\u0165 \u00falohu D.R., a syst\u00e9m vyberie \u010fal\u0161ie B.D.R.<\/p>\n

\"Tr\u00e9ning
\n
\nD\u00fafam, \u017ee ste pochopili v\u00fdber D.R. a B.D.R., ak nie, vr\u00e1tim sa k tejto ot\u00e1zke v jednom z nasleduj\u00facich vide\u00ed a podrobne vysvetl\u00edm tento proces. <\/p>\n

Tak, presk\u00famali sme, \u010do predstavuje Hello, popis datab\u00e1zy Database Descriptor a spr\u00e1vy LSR, LSU a LSA. Predt\u00fdm, ne\u017e prejdeme na \u010fal\u0161iu t\u00e9mu, porozpr\u00e1vajme sa trochu o cene OSPF. <\/p>\n

\"Tr\u00e9ning
\n
\nV Cisco sa cena trasy vypo\u010d\u00edtava pod\u013ea vzorca pomeru \u0161\u00edrky p\u00e1sma Reference bandwidth, ktor\u00e1 je predvolene nastaven\u00e1 na 100 Mbit\/s, k cene linky. Napr\u00edklad, pri prepojen\u00ed zariaden\u00ed cez s\u00e9riov\u00fd port, r\u00fdchlos\u0165 je 1,544 Mbit\/s a cena bude 64. Pri pou\u017eit\u00ed Ethernetov\u00e9ho pripojenia s r\u00fdchlos\u0165ou 10 Mbit\/s bude cena 10 a cena pripojenia FastEthernet s r\u00fdchlos\u0165ou 100 Mbit\/s bude rovn\u00e1 1. <\/p>\n

Pri pou\u017eit\u00ed Gigabit Ethernet m\u00e1me r\u00fdchlos\u0165 1000 Mbit\/s, av\u0161ak v tomto pr\u00edpade je r\u00fdchlos\u0165 v\u017edy pova\u017eovan\u00e1 za 1. Tak\u017ee, ak m\u00e1te v sieti Gigabit Ethernet, mali by ste zmeni\u0165 predvolen\u00e9 hodnoty Ref. BW na 1000. V tomto pr\u00edpade cena bude 1 a cel\u00e1 tabu\u013eka bude prepo\u010d\u00edtan\u00e1 s desiatkov\u00fdm zv\u00fd\u0161en\u00edm hodn\u00f4t cien. Po vytvoren\u00ed susedstva a zostaven\u00ed datab\u00e1zy LSDB prech\u00e1dzame k zostaveniu smerovacej tabu\u013eky. <\/p>\n

\"Tr\u00e9ning
\n
\nPo prijat\u00ed LSDB ka\u017ed\u00fd z routerov samostatne za\u010d\u00edna vytv\u00e1ra\u0165 zoznam tr\u00e1s pomocou algoritmu SPF. V na\u0161om sch\u00e9me router A vytvor\u00ed t\u00fato tabu\u013eku pre seba sam\u00e9ho. Napr\u00edklad, vypo\u010d\u00edta cenu trasy A-R1 a ur\u010d\u00ed ju rovnou 10. Pre zjednodu\u0161enie porozumenia sch\u00e9my predpokladajme, \u017ee router A ur\u010duje optim\u00e1lnu trasu k routeru B. Cena spojenia A-R1 je 10, cena spojenia A-R2 je 100 a cena trasy A-R3 je 11, teda s\u00fa\u010dtom trasy A-R1 (10) a R1-R3 (1).<\/p>\n

Ak sa router A chce dosta\u0165 k routeru R4, m\u00f4\u017ee to urobi\u0165 bu\u010f trasou A-R1-R4, alebo trasou A-R2-R4, pri\u010dom v oboch pr\u00edpadoch bud\u00fa ceny tr\u00e1s rovnak\u00e9: 10+100 = 100+10 = 110. Trasa A-R6 bude st\u00e1\u0165 100+1 = 101, \u010do u\u017e je lep\u0161ie. \u010ealej sa zva\u017euje cesta k routeru R5 cez trasu A-R1-R3-R5, ktorej cena bude 10+1+100 = 111. <\/p>\n

Cestu k routeru R7 je mo\u017en\u00e9 vykona\u0165 dvoma trasami: A-R1-R4-R7 alebo A-R2-R6-R7. Cena prvej bude 210, druhej \u2013 201, teda by sa mala zvoli\u0165 201. Tak\u017ee, aby dosiahol router B, m\u00f4\u017ee router A pou\u017ei\u0165 4 trasy.<\/p>\n

\"Tr\u00e9ning
\n
\nCena trasy A-R1-R3-R5-B bude 121. Trasa A-R1-R4-R7-B bude st\u00e1\u0165 220. Trasa A-R2-R4-R7-B m\u00e1 cenu 210 a A-R2-R6-R7-B stoj\u00ed 211. Na z\u00e1klade toho router A vyberie trasu s najni\u017e\u0161ou cenou, ktor\u00e1 je 121, a umiestni ju do routovacej tabu\u013eky. Toto je ve\u013emi zjednodu\u0161en\u00fd poh\u013ead na to, ako funguje algoritmus SPF. V skuto\u010dnosti sa do tabu\u013eky nezapisuj\u00fa len ozna\u010denia routerov, ktor\u00fdmi prech\u00e1dza optim\u00e1lna trasa, ale aj ozna\u010denia sp\u00e1jaj\u00facich ich portov a v\u0161etky ostatn\u00e9 potrebn\u00e9 inform\u00e1cie. <\/p>\n

Pozrime sa na \u010fal\u0161iu t\u00e9mu, ktor\u00e1 sa t\u00fdka routovac\u00edch z\u00f3n. Pri nastaven\u00ed OSPF zariaden\u00ed spolo\u010dnosti zvy\u010dajne v\u0161etky nach\u00e1dzaj\u00fa v jednej spolo\u010dnej z\u00f3ne. <\/p>\n

\"Tr\u00e9ning
\n
\n\u010co sa stane, ak zariadenie pripojen\u00e9 k routeru R3 n\u00e1hle zlyh\u00e1? Router R3 okam\u017eite za\u010dne posiela\u0165 routerom R5 a R1 spr\u00e1vu o tom, \u017ee kan\u00e1l s t\u00fdmto zariaden\u00edm u\u017e nefunguje, a v\u0161etky routery za\u010dn\u00fa v\u00fdmenu aktualiz\u00e1ci\u00ed o tejto udalosti. <\/p>\n

\"Tr\u00e9ning
\n
\nAk m\u00e1te 100 routerov, v\u0161etky aktualizuj\u00fa inform\u00e1cie o stave kan\u00e1lov, preto\u017ee s\u00fa v jednej spolo\u010dnej z\u00f3ne. To ist\u00e9 sa stane, ak zlyh\u00e1 jeden z susedn\u00fdch routerov \u2013 v\u0161etky zariadenia v z\u00f3ne si vymenia aktualiz\u00e1cie LSA. Po wymene t\u00fdchto spr\u00e1v sa zmen\u00ed sama topol\u00f3gia siete. Akon\u00e1hle k tomu d\u00f4jde, SPF prepo\u010d\u00edta routovacie tabu\u013eky pod\u013ea zmenen\u00fdch podmienok. Je to ve\u013emi n\u00e1ro\u010dn\u00fd proces a ak m\u00e1te v jednej z\u00f3ne tis\u00edc zariaden\u00ed, mus\u00edte monitorova\u0165 ve\u013ekos\u0165 pam\u00e4te routerov, aby bola dostato\u010dn\u00e1 na uchov\u00e1vanie v\u0161etk\u00fdch LSA a obrovskej datab\u00e1zy stavu kan\u00e1lov LSDB. Akon\u00e1hle v nejakej \u010dasti z\u00f3ny d\u00f4jde k zmen\u00e1m, algoritmus SPF okam\u017eite prepo\u010d\u00edta trasy. Pod\u013ea predvolieb sa LSA aktualizuje ka\u017ed\u00fdch 30 min\u00fat. Tento proces prebieha na v\u0161etk\u00fdch zariadeniach nie s\u00fa\u010dasne, av\u0161ak v ka\u017edom pr\u00edpade aktualiz\u00e1cie vykon\u00e1va ka\u017ed\u00fd router s peri\u00f3dou 30 min\u00fat. \u010c\u00edm viac sie\u0165ov\u00fdch zariaden\u00ed, t\u00fdm viac pam\u00e4te a \u010dasu je potrebn\u00e9 na aktualiz\u00e1ciu LSDB.<\/p>\n

T\u00fato probl\u00e9matiku mo\u017eno vyrie\u0161i\u0165, ak rozdel\u00edte jednu spolo\u010dn\u00fa z\u00f3nu na nieko\u013eko samostatn\u00fdch z\u00f3n, to znamen\u00e1, \u017ee pou\u017eijete multiz\u00f3novanie. Na to, aby ste to mohli realizova\u0165, mus\u00edte ma\u0165 pl\u00e1n alebo sch\u00e9mu celej siete, ktor\u00fa spravujete. Nulov\u00e1 z\u00f3na AREA 0 je va\u0161a hlavn\u00e1 z\u00f3na Main area. To je miesto, kde sa vykon\u00e1va pripojenie k vonkaj\u0161ej sieti, napr\u00edklad k internetu. Pri vytv\u00e1ran\u00ed nov\u00fdch z\u00f3n by ste sa mali riadi\u0165 pravidlom: v ka\u017edej z\u00f3ne mus\u00ed by\u0165 jeden hrani\u010dn\u00fd smerova\u010d ABR, Area Border Router. Hrani\u010dn\u00fd smerova\u010d m\u00e1 jedno rozhranie v jednej z\u00f3ne a druh\u00e9 rozhranie \u2013 v druhej z\u00f3ne. Napr\u00edklad, smerova\u010d R5 m\u00e1 rozhrania v z\u00f3ne 1 a z\u00f3ne 0. Ako som u\u017e povedal, ka\u017ed\u00e1 z\u00f3na mus\u00ed by\u0165 prepojen\u00e1 s nulovou z\u00f3nou, to znamen\u00e1, \u017ee mus\u00ed ma\u0165 hrani\u010dn\u00fd smerova\u010d, ktor\u00e9ho jedno rozhranie je pripojen\u00e9 k AREA 0. <\/p>\n

\"Tr\u00e9ning
\n
\nPredpokladajme, \u017ee spojenie R6-R7 zlyhalo. V takom pr\u00edpade sa aktualiz\u00e1cia LSA roz\u0161\u00edri iba po z\u00f3ne AREA 1 a bude sa t\u00fdka\u0165 iba tejto z\u00f3ny. Zariadenia v z\u00f3ne 2 a v z\u00f3ne 0 sa o tom ani nedozvedia. Hrani\u010dn\u00fd smerova\u010d R5 vykon\u00e1va sumariz\u00e1ciu inform\u00e1ci\u00ed o tom, \u010do sa deje v jeho z\u00f3ne, a posiela do hlavnej z\u00f3ny AREA 0 sum\u00e1rne inform\u00e1cie o stave siete. Zariadenia v jednej z\u00f3ne nemusia vedie\u0165 o v\u0161etk\u00fdch zmen\u00e1ch LSA v in\u00fdch z\u00f3nach, preto\u017ee smerova\u010d ABR bude preposiela\u0165 s\u00fahrnn\u00e9 inform\u00e1cie o tras\u00e1ch z jednej z\u00f3ny do druhej. <\/p>\n

Ak ste si nie \u00faplne ist\u00ed konceptom z\u00f3n, m\u00f4\u017eete sa dozvedie\u0165 viac v nasleduj\u00facich lekci\u00e1ch, ke\u010f sa budeme zaobera\u0165 nastaven\u00edm smerovania OSPF a presk\u00famame nieko\u013eko pr\u00edkladov. <\/p>\n

\r\n \"Prehrajte\r\n
<\/div>\r\n <\/div><\/center>
\n\u010eakujeme, \u017ee s nami zost\u00e1vate. P\u00e1\u010dia sa v\u00e1m na\u0161e \u010dl\u00e1nky? Chcete vidie\u0165 viac zauj\u00edmav\u00fdch materi\u00e1lov? Podporte n\u00e1s objednan\u00edm alebo odpor\u00fa\u010dan\u00edm priate\u013eom, 30% z\u013eava pre pou\u017e\u00edvate\u013eov Chabra na unik\u00e1tny ekvivalent entry-level serverov, ktor\u00fd sme pre v\u00e1s vytvorili:<\/b> V\u0161etky pravdy o VPS (KVM) E5-2650 v4 (6 jadier) 10GB DDR4 240GB SSD 1Gbps od 20 dol\u00e1rov alebo ako spr\u00e1vne rozdeli\u0165 server?<\/a><\/noindex> (k dispoz\u00edcii varianty s RAID1 a RAID10, a\u017e 24 jadier a a\u017e 40GB DDR4).<\/p>\n

Dell R730xd za polovicu?<\/b> Len u n\u00e1s 2 x Intel TetraDeca-Core Xeon 2x E5-2697v3 2.6GHz 14C 64GB DDR4 4x960GB SSD 1Gbps 100 TB od 199 dol\u00e1rov<\/a><\/noindex> v Holandsku! Dell R420 \u2014 2x E5-2430 2.2Ghz 6C 128GB DDR3 2x960GB SSD 1Gbps 100TB \u2014 od 99 dol\u00e1rov!<\/b><\/b> Pre\u010d\u00edtajte si o tom Ako vybudova\u0165 infra\u0161trukt\u00faru korpor\u00e1tneho typu s pou\u017eit\u00edm serverov Dell R730xd E5-2650 v4 s cenou 9000 eur za zlomok ceny?<\/a><\/noindex>
\n
Zdroj: habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0421\u0435\u0433\u043e\u0434\u043d\u044f \u043c\u044b \u043d\u0430\u0447\u043d\u0435\u043c \u0438\u0437\u0443\u0447\u0435\u043d\u0438\u0435 \u043c\u0430\u0440\u0448\u0440\u0443\u0442\u0438\u0437\u0430\u0446\u0438\u0438 \u043f\u043e \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0443 OSPF. \u042d\u0442\u0430 \u0442\u0435\u043c\u0430, \u043a\u0430\u043a \u0438 \u0440\u0430\u0441\u0441\u043c\u043e\u0442\u0440\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 EIGRP, \u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u0432\u0430\u0436\u043d\u0435\u0439\u0448\u0435\u0439 \u0432\u043e \u0432\u0441\u0435\u043c \u043a\u0443\u0440\u0441\u0435 CCNA. \u041a\u0430\u043a \u0432\u0438\u0434\u0438\u0442\u0435, \u0440\u0430\u0437\u0434\u0435\u043b 2.4 \u043d\u0430\u0437\u044b\u0432\u0430\u0435\u0442\u0441\u044f \u00ab\u041d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0430, \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0430 \u0438 \u043d\u0435\u043f\u043e\u043b\u0430\u0434\u043a\u0438 \u0435\u0434\u0438\u043d\u0438\u0447\u043d\u043e\u0439 \u0437\u043e\u043d\u044b \u0438 \u043c\u0443\u043b\u044c\u0442\u0438\u0437\u043e\u043d\u044b OSPFv2 \u0434\u043b\u044f \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 IPv4 (\u0437\u0430 \u0438\u0441\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u0435\u043c \u0430\u0443\u0442\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u0438, \u0444\u0438\u043b\u044c\u0442\u0440\u0430\u0446\u0438\u0438, \u0440\u0443\u0447\u043d\u043e\u0433\u043e \u0441\u0443\u043c\u043c\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043c\u0430\u0440\u0448\u0440\u0443\u0442\u043e\u0432, \u043f\u0435\u0440\u0435\u0440\u0430\u0441\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d\u0438\u044f, \u0442\u0443\u043f\u0438\u043a\u043e\u0432\u043e\u0439 \u043e\u0431\u043b\u0430\u0441\u0442\u0438, \u0432\u0438\u0440\u0442\u0443\u0430\u043b\u044c\u043d\u043e\u0439 \u0441\u0435\u0442\u0438 \u0438 LSA)\u00bb. \u0422\u0435\u043c\u0430 OSPF \u0434\u043e\u0441\u0442\u0430\u0442\u043e\u0447\u043d\u043e […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":28774,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[688],"tags":[],"class_list":["post-38332","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\udd47\u0160kolenie Cisco 200-125 CCNA v3.0. De\u0148 44. \u00davod do OSPF | ProHoster","description":"Dnes za\u010dneme \u0161tudova\u0165 smerovanie pomocou protokolu OSPF. 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