Namhlanje siza kuqala ukufunda iirouter. Ukuba ugqibile ikhosi yam yevidiyo ukusuka kweyokuqala ukuya kwisifundo se-17, ngoko sele ufunde iziseko zokutshintsha. Ngoku siqhubela phambili kwisixhobo esilandelayo - i-router. Njengoko uyazi kwisifundo sevidiyo sangaphambili, enye yezihloko zekhosi yeCCNA ibizwa ngokuba yiCisco Switching & Routing.
Kolu chungechunge, asiyi kufunda iirouter zeCisco, kodwa siya kujonga ingcamango yomzila ngokubanzi. Siza kuba nemixholo emithathu. Eyokuqala sisishwankathelo sento osele uyazi malunga nee-routers kunye nencoko malunga nendlela enokusetyenziswa ngayo ngokubambisana nolwazi olufumene kwinkqubo yokufunda iiswitshi. Kufuneka siqonde ukuba iiswitshi kunye neerotha zisebenzisana njani.
Okulandelayo, siza kujonga ukuba yintoni na indlela, ithetha ukuthini, kwaye isebenza njani, kwaye emva koko siya kudlulela kwiindidi zeendlela zokuziphatha. Namhlanje ndisebenzisa i-topology osele uyibonile kwizifundo ezidlulileyo.
Sijonge indlela idatha ehamba ngayo kwinethiwekhi kunye nendlela i-TCP yokuxhawulana kwezandla ezintathu yenziwa. Umyalezo wokuqala othunyelwe ngenethiwekhi yipakethi yeSYN. Makhe sijonge indlela ukuxhawula ngeendlela ezintathu kwenzeka xa ikhomputha enedilesi ye-IP 10.1.1.10 ifuna ukuqhagamshelana nomncedisi 30.1.1.10, oko kukuthi, izama ukuseka uxhumano lwe-FTP.
Ukuqala uxhulumaniso, ikhomputha idala i-port yomthombo ngenombolo engahleliweyo 25113. Ukuba ukhohliwe ukuba kwenzeka njani oku, ndikucebisa ukuba ubuyekeze izifundo zevidiyo zangaphambili ezixubushe ngalo mbandela.
Okulandelayo, ibeka inombolo yezibuko ekuyiwa kuyo kwisakhelo kuba iyazi ukuba kufuneka iqhagamshele kwi-port 21, emva koko yongeza ulwazi lwe-OSI Layer 3, eyidilesi yayo ye-IP kunye nedilesi ye-IP yokufikela. Idatha enamachaphaza ayitshintshi de ifike kwindawo yokugqibela. Xa befikelele kumncedisi, nabo abatshintshi, kodwa umncedisi wongeza ulwazi lwenqanaba lesibini kwisakhelo, oko kukuthi, idilesi ye-MAC. Oku kungenxa yokuba iiswitshi zibona kuphela ulwazi lwe-OSI yenqanaba lesi-2. Kule meko, i-router kuphela kwesixhobo sothungelwano esiqwalasela ulwazi lweNqanaba 3; ngokwemvelo, ikhompyutha isebenza ngolu lwazi. Ngoko, utshintsho lusebenza kuphela ngolwazi lwenqanaba lesi-XNUMX, kwaye i-router isebenza kuphela ngolwazi lwenqanaba le-XNUMX.
Umtshintshi uyazi idilesi ye-MAC yomthombo XXXX:XXXX:1111 kwaye ifuna ukwazi idilesi ye-MAC yomncedisi ikhompyutha efikelela kuyo. Ithelekisa idilesi ye-IP yomthombo kunye nedilesi yendawo, iyaqonda ukuba ezi zixhobo zifumaneka kwii-subnets ezahlukeneyo, kwaye zithatha isigqibo sokusebenzisa isango lokufikelela kwi-subnet eyahlukileyo.
Ndihlala ndibuzwa umbuzo wokuba ngubani othatha isigqibo sokuba yeyiphi idilesi ye-IP yesango. Okokuqala, kugqitywe ngumlawuli wenethiwekhi, owenza inethiwekhi kwaye unikeze idilesi ye-IP kwisixhobo ngasinye. Njengomlawuli, unokwabela i-router yakho nayiphi na idilesi ngaphakathi koluhlu lweedilesi ezivumelekileyo kwi-subnet yakho.Le idla ngokuba yidilesi yokuqala okanye yokugqibela esebenzayo, kodwa akukho migaqo ingqongqo malunga nokuyabela. Kwimeko yethu, umlawuli wanikezela idilesi yesango, okanye i-router, 10.1.1.1 kwaye wayinika i-port F0/0.
Xa useka uthungelwano kwikhompyuter ngedilesi ye-IP engatshintshiyo ye-10.1.1.10, unikezela imaski ye-subnet ye-255.255.255.0 kunye nesango elingagqibekanga le-10.1.1.1. Ukuba awusebenzisi idilesi engatshintshiyo, ngoko ikhomputha yakho isebenzisa i-DHCP, enika idilesi eguqukayo. Kungakhathaliseki ukuba yeyiphi idilesi ye-IP esetyenziswa yikhompyutha, i-static okanye i-dynamic, kufuneka ibe nedilesi yesango lokufikelela kwenye inethiwekhi.
Ngaloo ndlela, i-computer 10.1.1.10 iyazi ukuba kufuneka ithumele isakhelo kwi-router 10.1.1.1. Olu tshintsho lwenzeka ngaphakathi kwinethiwekhi yendawo, apho idilesi ye-IP ayinandaba, kuphela idilesi ye-MAC ibalulekile apha. Makhe sicinge ukuba ikhomputha ayizange inxibelelane ne-router ngaphambili kwaye ayiyazi idilesi yayo ye-MAC, ngoko ke kufuneka iqale ithumele isicelo se-ARP esibuza zonke izixhobo kwi-subnet: "hey, ngubani na kuni onedilesi 10.1.1.1? Nceda undixelele idilesi yakho ye-MAC! Ekubeni i-ARP ngumyalezo wosasazo, ithunyelwa kuzo zonke izibuko zazo zonke izixhobo, kuquka i-router.
IKhompyutha 10.1.1.12, emva kokuba ifumene i-ARP, icinga ukuba: "hayi, idilesi yam ayikho 10.1.1.1," kwaye ilahla isicelo, ikhompyutha 10.1.1.13 yenza okufanayo. I-router, xa ifumene isicelo, iyaqonda ukuba nguye obuzwayo, kwaye ithumela idilesi ye-MAC ye-port F0 / 0 - kwaye zonke izibuko zinedilesi eyahlukileyo ye-MAC - kwikhompyutheni 10.1.1.10. Ngoku, ukwazi idilesi yesango XXXX:AAAA, kulo mzekelo idilesi yendawo, ikhomputha iyongeza ekupheleni kwesakhelo esibhekiswe kumncedisi. Kwangaxeshanye, icwangcisa i-header yesakhelo se-FCS/CRC, eyimposiso yothumelo lokukhangela indlela.
Emva koko, isakhelo sekhompyutha 10.1.1.10 sithunyelwa ngaphaya kweengcingo kwi-router 10.1.1.1. Emva kokufumana isakhelo, i-router isusa i-FCS / CRC isebenzisa i-algorithm efanayo nekhompyutheni yokuqinisekisa. Idatha ayikho ngaphezu kwengqokelela enye kunye no-zero. Ukuba idatha yonakalisiwe, oko kukuthi, i-1 iba yi-0 okanye i-0 iba yinye, okanye kukho ukuvuza kwedatha, okuhlala kwenzeka xa usebenzisa i-hub, ngoko isixhobo kufuneka sithumele kwakhona isakhelo kwakhona.
Ukuba ukukhangela kwe-FCS / CRC kuphumelele, i-router ibheka umthombo kunye nendawo yokufikela iidilesi ze-MAC kwaye izisuse, ekubeni le yiNgcaciso yesi-2, kwaye iqhubela kumzimba wesakhelo, oqulethe ulwazi lweNqanaba lesi-3. Ukusuka kuyo ufunda ukuba ulwazi oluqulethwe kwisakhelo senzelwe isixhobo esinedilesi ye-IP 30.1.1.10.
I-router ngandlela-thile iyazi apho esi sixhobo sikhoyo. Khange sixoxe ngalo mba xa sijonga indlela iiswitshi ezisebenza ngayo, sizakuyijonga ngoku. I-router inamazibuko ama-4, ngoko ke ndongeze uqhagamshelo olungakumbi kuyo. Ngoko, i-router iyazi njani ukuba idatha yesixhobo esinedilesi ye-IP 30.1.1.10 kufuneka ithunyelwe nge-port F0/1? Kutheni ingazithumeli ngezibuko F0/3 okanye F0/2?
Inyani kukuba i-router isebenza kunye netafile yomzila. Umzila ngamnye unetafile enjalo ekuvumela ukuba wenze isigqibo malunga nokuba yeyiphi i-port yokuhambisa isakhelo esithile.
Kule meko, i-port F0/0 iqwalaselwe kwidilesi ye-IP 10.1.1.1 kwaye oku kuthetha ukuba idibaniswe nenethiwekhi 10.1.1.10/24. Ngokufanayo, i-port F0/1 iqwalaselwe kwidilesi 20.1.1.1, oko kukuthi, iqhagamshelwe kwinethiwekhi 20.1.1.0/24. I-router iyazazi zombini ezi networks kuba ziqhagamshelwe ngokuthe ngqo kumazibuko ayo. Ngaloo ndlela, ulwazi lokuba i-traffic yenethiwekhi 10.1.10 / 24 kufuneka idlule kwi-port F0 / 0, kunye nenethiwekhi ye-20.1.1.0/24 nge-port F0 / 1, iyaziwa ngokungagqibekanga. Ngaba i-router yazi njani ukuba yeyiphi izibuko ukuze isebenze namanye amanethiwekhi?
Siyabona ukuba inethiwekhi 40.1.1.0/24 iqhagamshelwe kwi-port F0/2, inethiwekhi 50.1.1.0/24 iqhagamshelwe kwi-port F0/3, kunye nenethiwekhi 30.1.1.0/24 idibanisa i-router yesibini kumncedisi. I-router yesibini nayo inetafile yomzila, ethi inethiwekhi ye-30. ixhunyiwe kwi-port yayo, masiyibonise i-0/1, kwaye idibaniswe kwi-router yokuqala nge-port 0/0. Le router iyazi ukuba i-port yayo 0/0 iqhagamshelwe kuthungelwano 20., kunye ne-port 0/1 iqhagamshelwe kwinethiwekhi 30., kwaye ayazi enye into.
Ngokufanayo, i-router yokuqala iyazi malunga neenethiwekhi ze-40. kunye ne-50. eziqhagamshelwe kumachweba 0/2 kunye no-0/3, kodwa awazi nto malunga nenethiwekhi ye-30. I-protocol yomzila inika ii-routers ngolwazi abangenalo ngokungagqibekanga. Indlela ezinxibelelana ngayo ezi routers sisiseko somzila, kwaye kukho umzila oguquguqukayo kunye nozinzileyo.
Umzila we-Static kukuba i-router yokuqala inikwe ulwazi: ukuba ufuna ukuqhagamshelana nenethiwekhi 30.1.1.0/24, ngoko kufuneka usebenzise i-port F0/1. Nangona kunjalo, xa i-router yesibini ifumana i-traffic kwi-server ejoliswe kwikhompyutheni ye-10.1.1.10, ayiyazi into enokuyenza ngayo, kuba itafile yayo yomzila iqulethe ulwazi malunga neenethiwekhi 30 kunye ne-20. Ngoko ke, le router nayo ifuna ukubhalisa umzila ongatshintshiyo : Ukuba ifumana itrafikhi yomsebenzi womnatha we-10., kufuneka iyithumele ngezibuko 0/0.
Ingxaki kunye nomzila we-static kukuba kufuneka ndiqwalasele ngesandla umzila wokuqala ukuba usebenze kunye nenethiwekhi 30. kunye ne-router yesibini ukuze isebenze kunye nenethiwekhi 10. Oku kulula ukuba ndinee-routers ezi-2 kuphela, kodwa xa ndine-router ezili-10, ukuseta. indlela engatshintshiyo ithatha ixesha elininzi. Kule meko, kunengqiqo ukusebenzisa umzila oguqukayo.
Ke, emva kokufumana isakhelo kwikhompyuter, i-router yokuqala ijonga itafile yayo kwaye ithatha isigqibo sokuyithumela ngezibuko F0/1. Ngaxeshanye, yongeza idilesi yeMAC yomthombo XXXX.BBBB kunye nendawo yokufikela idilesi ye-MAC XXXX.CCSS kwisakhelo.
Emva kokufumana le freyimu, i-router yesibini "inqumle" iidilesi ze-MAC ezinxulumene noluhlu lwe-OSI yesibini kwaye iqhubele phambili kulwazi lwesithathu. Uyabona ukuba idilesi ye-IP yendawo 3 yeyothungelwano olufanayo njenge-port 30.1.1.10/0 ye-router, yongeza idilesi ye-MAC yomthombo kunye nedilesi ye-MAC yendawo kwisakhelo kwaye ithumela isakhelo kumncedisi.
Njengoko besenditshilo, emva koko inkqubo efanayo iphinda iphindwe kwicala elichaseneyo, oko kukuthi, inqanaba lesibini lokuxhawula liyaqhutywa, apho umncedisi uthumela umyalezo we-SYN ACK. Ngaphambi kokwenza oku, ilahla lonke ulwazi olungeyomfuneko kwaye ishiya kuphela ipakethi ye-SYN.
Emva kokufumana le pakethi, i-router yesibini iphonononga ulwazi olufunyenweyo, iyongezelela kwaye iyithumele.
Ke, kwizifundo ezidlulileyo sifunde indlela iswitshi esebenza ngayo, kwaye ngoku sifunde indlela iirutha ezisebenza ngayo. Makhe siphendule umbuzo wokuba yintoni na indlela kwindlela yehlabathi. Masithi udibana nophawu lwendlela olunjalo olufakwe kwisiphambuka esijikelezayo. Uyabona ukuba isebe lokuqala likhokelela kwiRAF Fairfax, elesibini kwisikhululo seenqwelomoya, elesithathu emazantsi. Ukuba uthatha indlela yesine ephumayo uya kuba ufile, kodwa ngeyesihlanu ungaqhuba kumbindi wedolophu uye kwinqaba yaseBraxby.
Ngokubanzi, umzila yinto enyanzelisa i-router ukuba yenze izigqibo malunga nokuba ithumela phi i-traffic. Kule meko, wena, njengomqhubi, kufuneka uthathe isigqibo malunga nokuba yeyiphi indlela yokuphuma kwi-intersection. Kwiinethiwekhi, iirotha kufuneka zenze izigqibo malunga nokuba zithumela phi iipakethi okanye iifreyimu. Kufuneka uqonde ukuba umzila uvumela ukuba wenze iitafile ngokusekelwe kwii-routers ezithatha ezi zigqibo.
Njengoko benditshilo, kukho indlela emileyo kunye neguqukayo. Makhe sijonge kumzila omileyo, endiya kuzoba izixhobo ezi-3 eziqhagamshelwe omnye komnye, kunye nesixhobo sokuqala nesesithathu esiqhagamshelwe kuthungelwano. Makhe sicinge ukuba womnatha omnye 10.1.1.0 ufuna ukunxibelelana womnatha 40.1.1.0, kwaye phakathi imizila kukho iinethiwekhi 20.1.1.0 kunye 30.1.1.0.
Kule meko, izibuko ze-router kufuneka zibe kwii-subnets ezahlukeneyo. Umzila 1 ngokungagqibekanga uyazi kuphela malunga neenethiwekhi 10. kwaye 20. kwaye akazi nto malunga nezinye iinethiwekhi. Umzila 2 uyazi kuphela uthungelwano 20. yaye 30. kuba ziqhagamshelwe kuyo, kwaye umzila 3 uyazi kuphela uthungelwano 30. yaye 40. Ukuba womnatha 10. ufuna ukuqhagamshelana womnatha 40., Kufuneka ukuxelela umzila 1 malunga womnatha 30 ... kwaye ukuba ufuna ukutshintshela isakhelo kwinethiwekhi 40., kufuneka asebenzise ujongano lomsebenzi womnatha 20. kwaye athumele isakhelo kuthungelwano olufanayo 20.
Ndimele ndinike iindlela ezi-2 kwi-router yesibini: ukuba ifuna ukuhambisa ipakethi ukusuka kuthungelwano 40. ukuya kwinethiwekhi 10., ngoko ke kufuneka isebenzise i-port yenethiwekhi 20., kunye nokudlulisa ipakethi ukusuka kwinethiwekhi 10. ukuya kwinethiwekhi 40. - inethiwekhi port 30. Ngokufanayo, kufuneka ndibonelele nge-router 3 ulwazi malunga neenethiwekhi 10. kunye ne-20.
Ukuba unothungelwano oluncinci, ke ukuseta indlela engatshintshiyo kulula kakhulu. Nangona kunjalo, okukhona uthungelwano lukhula, kokukhona kuvela iingxaki ezininzi ngomzila omileyo. Makhe sicinge ukuba wenze unxibelelwano olutsha oludibanisa ngokuthe ngqo iirotha zokuqala nezesithathu. Kule meko, i-protocol ye-router eguquguqukayo iya kuhlaziya ngokuzenzekelayo itafile ye-Router 1 ngokulandelayo: "ukuba ufuna ukuqhagamshelana ne-Router 3, sebenzisa indlela ethe ngqo"!
Kukho iindidi ezimbini zeendlela zokuziphatha: i-Internal Gateway Protocol IGP kunye ne-External Gateway Protocol EGP. Iprothokholi yokuqala isebenza kwindlela eyahlukileyo, ezimeleyo eyaziwa ngokuba yisizinda somzila. Khawucinge ukuba unombutho omncinci oneendlela ezi-5 kuphela. Ukuba sithetha kuphela uqhagamshelwano phakathi kwezi routers, ngoko sithetha IGP, kodwa ukuba usebenzisa inethiwekhi yakho ukunxibelelana Internet, njengoko ababoneleli ISP ukwenza, ngoko usebenzisa EGP.
I-IGP isebenzisa iiprothokholi ezi-3 ezithandwayo: i-RIP, i-OSPF kunye ne-EIGRP. Ikharityhulam ye-CCNA ikhankanya kuphela iiprothokholi ezimbini zokugqibela kuba i-RIP iphelelwe lixesha. Le yeyona ndlela ilula yeendlela zokuziphatha kwaye isasetyenziswa kwezinye iimeko, kodwa ayiboneleli ngokhuseleko lwenethiwekhi oluyimfuneko. Esi sesinye sezizathu zokuba iCisco iyikhuphele ngaphandle i-RIP kwikhosi yoqeqesho. Nangona kunjalo, ndiza kukuxelela ngayo nangona kunjalo kuba ukufunda kukunceda uqonde iziseko zomzila.
Ulwahlulo lweprotocol yeEGP lusebenzisa iprotocol ezimbini: BGP kunye ne EGP protocol ngokwayo. Kwikhosi ye-CCNA, siya kugubungela kuphela i-BGP, i-OSPF, kunye ne-EIGRP. Ibali malunga ne-RIP inokuthathwa njengolwazi lwebhonasi, oluya kubonakaliswa kwelinye lezifundo zevidiyo.
Kukho ezinye iindidi ezi-2 zeendlela zokuziphatha: Iiprothokholi zeVector yomgama kunye neeprothokholi ze-Link State.
Ukuphumelela kokuqala kujonge umgama kunye neevektha zendlela. Umzekelo, ndiyakwazi ukuseka uqhagamshelo ngqo phakathi kwe-router R1 kunye ne-R4, okanye ndingenza uqhagamshelwano ecaleni kwendlela R1-R2-R3-R4. Ukuba sithetha ngeeprothokholi zomzila ezisebenzisa indlela yevector yomgama, ngoko kulo mzekelo uxhulumaniso luya kuhlala luqhutyelwa kwindlela emfutshane. Ayinamsebenzi into yokuba olu xhulumaniso luyakuba nesantya esisezantsi. Kwimeko yethu, le yi-128 kbps, ehamba kancinci kunokudibanisa kwindlela ye-R1-R2-R3-R4, apho isantya si-100 Mbps.
Makhe sithathele ingqalelo umgama vector protocol RIP. Ndiya kutsala inethiwekhi 1 phambi kwe-router R10, kunye nenethiwekhi 4 emva kwe-router R40. Makhe sicinge ukuba kukho iikhomputha ezininzi kule nethiwekhi. Ukuba ndifuna ukunxibelelana phakathi kothungelwano 10. R1 kunye nenethiwekhi 40. R4, ngoko ke ndiya kwabela indlela engatshintshiyo ku-R1 njengaye: βukuba ufuna ukuqhagamshela kuthungelwano 40., sebenzisa uqhagamshelwano oluthe ngqo kwirutha R4.β Ngexesha elifanayo, kufuneka ndilungiselele ngesandla i-RIP kuzo zonke ii-routers ezi-4. Emva koko itheyibhile yomzila i-R1 iya kuthi ngokuzenzekelayo ukuba inethiwekhi 10. ifuna ukunxibelelana nenethiwekhi 40., kufuneka isebenzise uxhumano oluthe ngqo lwe-R1-R4. Nokuba i-bypass ijika ikhawuleza, i-Distance Vector protocol isaza kukhetha eyona ndlela imfutshane kunye nomgama omfutshane wothumelo.
I-OSPF yi-protocol ye-link-state routing ehlala ijonga imeko yamacandelo othungelwano. Kule meko, ivavanya isantya samajelo, kwaye ukuba ibona ukuba isantya sokuhanjiswa kwezithuthi kwijelo le-R1-R4 siphantsi kakhulu, ikhetha indlela ngesantya esiphezulu se-R1-R2-R3-R4, nokuba ubude bugqitha eyona ndlela imfutshane. Ngaloo ndlela, ukuba ndiqwalasela i-protocol ye-OSPF kuzo zonke ii-routers, xa ndizama ukudibanisa inethiwekhi 40. kwinethiwekhi 10., i-traffic iya kuthunyelwa endleleni R1-R2-R3-R4. Ke, i-RIP yiprotocol yevector yomgama, kwaye i-OSPF yiprotocol yendlela yokunxibelelana.
Kukho enye iprotocol - i-EIGRP, iprotocol ye-Cisco yobunikazi. Ukuba sithetha ngezixhobo zenethiwekhi ezivela kwabanye abavelisi, umzekelo, iJuniper, abaxhasi i-EIGRP. Le yiprotocol yomzila ebalaseleyo esebenza kakhulu kune-RIP kunye ne-OSPF, kodwa inokusetyenziswa kuphela kuthungelwano olusekwe kwizixhobo zeCisco. Kamva ndiza kukuxelela ngokubanzi ukuba kutheni le protocol ilungile. Okwangoku, ndiza kuqaphela ukuba i-EIGRP idibanisa iimpawu zeprothokholi ye-vector yomgama kunye neeprothokholi zomzila we-link-state, ezimele i-hybrid protocol.
Kwisifundo sevidiyo esilandelayo siza kuza ngokusondeleyo kuqwalaselo lweerutha zeCisco; Ndiza kukuxelela kancinci malunga nenkqubo yokusebenza yeCisco IOS, elungiselelwe zombini iiswitshi kunye neerotha. Ngethemba, ngoSuku lwe-19 okanye ngoSuku lwama-20, siya kungena kwiinkcukacha ezithe kratya malunga neeprothokholi zomzila, kwaye ndiza kubonisa indlela yokuqwalasela iirutha zeCisco usebenzisa iinethiwekhi ezincinci njengemizekelo.
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