Namhlanje, siza kuqala ngokugxila kwi-TCP. Ngaphambili kwisahluko esimalunga nokubekwa kwee-layering, sikhankanye ingongoma ebalulekileyo. Kwi-network layer nangaphantsi, kubhekiselele ngakumbi kunxibelelwano phakathi kwe-host ne-host, oko kuthetha ukuba ikhompyutha yakho kufuneka yazi ukuba iphi enye ikhompyutha ukuze iqhagamshelane nayo. Nangona kunjalo, unxibelelwano kwinethiwekhi ludla ngokuba lunxibelelwano phakathi kweenkqubo ezahlukeneyo kunokuba lunxibelelwano phakathi koomatshini. Ke ngoko, i-TCP protocol yazisa ingcamango ye-port. I-port ingasetyenziswa yinkqubo enye kuphela, ebonelela ngonxibelelwano oluthe ngqo phakathi kweenkqubo zesicelo ezisebenza kwii-host ezahlukeneyo.
Umsebenzi womaleko wothutho kukubonelela ngeenkonzo zonxibelelwano ngqo phakathi kweenkqubo zesicelo ezisebenza kwiihost ezahlukeneyo, ngoko ke yaziwa ngokuba yiprotocol yokuphela ukuya ekupheleni. Umaleko wothutho ufihla iinkcukacha eziphambili zenethiwekhi, okuvumela inkqubo yesicelo ukuba ibone ngathi kukho umjelo wonxibelelwano olusengqiqweni phakathi kwezi zinto zimbini zomaleko wothutho.
I-TCP imele iTransmission Control Protocol kwaye yaziwa njengeprotocol ejolise kunxibelelwano. Oku kuthetha ukuba ngaphambi kokuba olunye usetyenziso luqale ukuthumela idatha kolunye, ezi nkqubo zimbini kufuneka zenze i-handshake. I-Handshake yinkqubo edibeneyo ngokwengqiqo eqinisekisa ukudluliselwa okuthembekileyo kunye nokwamkelwa kwedatha ngocwangco. Ngexesha le-handshake, unxibelelwano lusekwa phakathi komthombo kunye neehostele zendawo ngokutshintshiselana uthotho lweepakethi zolawulo kunye nokuvumelana ngemimiselo ethile kunye nemithetho ukuqinisekisa ukudluliselwa kwedatha ngempumelelo.
Yintoni i-TCP? (Ukudibanisa kwamI-Network TapkwayeUmthengisi wePakethi yeNethiwekhiingacubungula zombini iiPakethi zeTCP okanye zeUDP)
I-TCP (iTransmission Control Protocol) yinkqubo yonxibelelwano lwendlela yothutho esekwe kunxibelelwano, ethembekileyo, esekelwe kwi-byte-stream.
Ijolise kunxibelelwano: Unxibelelwano olujolise kunxibelelwano luthetha ukuba unxibelelwano lwe-TCP lunxibelelwano oluvela kumntu omnye ukuya komnye, oko kukuthi, unxibelelwano oluvela kwindawo enye ukuya kwenye, ngokungafaniyo ne-UDP, enokuthumela imiyalezo kwiihostele ezininzi ngaxeshanye, ngoko ke unxibelelwano oluvela kumntu omnye ukuya kwabanye alunakufezekiswa.
Ithembekile: Ukuthembeka kwe-TCP kuqinisekisa ukuba iipakethi zihanjiswa ngokuthembekileyo kumkeli nokuba kukho utshintsho kwikhonkco lenethiwekhi, nto leyo eyenza ifomathi yepakethi yeprotocol ye-TCP ibe nzima ngakumbi kuneye-UDP.
Isekelwe kwi-Byte-stream: Uhlobo lwe-TCP olusekelwe kwi-byte-stream luvumela ukuhanjiswa kwemiyalezo yalo naluphi na ubungakanani kwaye luqinisekisa ulandelelwano lwemiyalezo: nokuba umyalezo wangaphambili awukafunyanwa ngokupheleleyo, kwaye nokuba ii-byte ezilandelayo zifunyenwe, i-TCP ayizukuzihambisa kwi-application layer ukuze zicutshungulwe kwaye iza kulahla ngokuzenzekelayo iipakethi eziphindwe kabini.
Nje ukuba i-host A kunye ne-host B ziqalise uqhagamshelo, usetyenziso lufuna ukusebenzisa umgca wonxibelelwano olubonakalayo ukuthumela nokufumana idatha, ngaloo ndlela kuqinisekiswe ukudluliselwa kwedatha. I-TCP protocol inoxanduva lokulawula imisebenzi efana nokusekwa koqhagamshelo, ukunqanyulwa, kunye nokubamba. Kufuneka kuqatshelwe ukuba apha sithi umgca obonakalayo uthetha kuphela ukuseka uqhagamshelo, uqhagamshelo lwe-TCP protocol lubonisa kuphela ukuba amacala omabini anokuqalisa ukudluliselwa kwedatha, kunye nokuqinisekisa ukuthembeka kwedatha. Ii-routing kunye nee-transport nodes ziphathwa zizixhobo zenethiwekhi; i-TCP protocol ngokwayo ayikhathali ngezi nkcukacha.
Uqhagamshelo lwe-TCP yinkonzo epheleleyo ye-duplex, oko kuthetha ukuba i-host A kunye ne-host B zinokudlulisela idatha kuzo zombini iindlela kuqhagamshelo lwe-TCP. Oko kukuthi, idatha inokudluliselwa phakathi kwe-host A kunye ne-host B ngendlela yokuhamba kwe-bidirectional.
I-TCP igcina idatha okwethutyana kwi-send buffer yonxibelelwano. Le send buffer yenye yee-cache ezicwangcisiweyo ngexesha lokuxhawulana ngeendlela ezintathu. Emva koko, i-TCP iya kuthumela idatha kwi-send cache kwi-receive cache ye-destination host ngexesha elifanelekileyo. Ngokwenyani, intanga nganye iya kuba ne-send cache kunye ne-receive cache, njengoko kubonisiwe apha:
I-send buffer yindawo yenkumbulo egcinwa yi-TCP ukuphunyezwa kwicala lomthumeli esetyenziselwa ukugcina idatha ethunyelwayo okwethutyana. Xa ukuxhawulana ngendlela ezintathu kwenziwa ukuze kusekwe uqhagamshelo, i-send cache iyamiselwa kwaye isetyenziswe ukugcina idatha. I-send buffer ilungiswa ngokuguquguqukayo ngokwe-network congestion kunye nempendulo evela kummkeli.
I-receive buffer yindawo yememori egcinwa yi-TCP ukuphunyezwa kwicala lokwamkela elisetyenziselwa ukugcina idatha efunyenweyo okwethutyana. I-TCP igcina idatha efunyenweyo kwi-receive cache kwaye ilinde ukuba usetyenziso oluphezulu luyifunde.
Qaphela ukuba ubungakanani be-send cache kunye ne-receive cache bunqunyelwe, xa i-cache igcwele, i-TCP inokusebenzisa amaqhinga athile, njengolawulo lokuxinana, ulawulo lokuhamba, njl.njl., ukuqinisekisa ukuhanjiswa kwedatha okuthembekileyo kunye nozinzo lwenethiwekhi.
Kwiinethiwekhi zekhompyutha, ukudluliselwa kwedatha phakathi kweehostele kwenziwa ngokusebenzisa amacandelo. Ngoko ke yintoni icandelo lepakethi?
I-TCP idala icandelo le-TCP, okanye icandelo leepakethi, ngokwahlula umjelo ongenayo ube ziinxalenye kunye nokongeza ii-headers ze-TCP kwinxalenye nganye. Icandelo ngalinye linokudluliselwa kuphela ixesha eliqingqiweyo kwaye alinakudlula i-Maximum Segment Size (MSS). Xa lisiya ezantsi, icandelo leepakethi lidlula kwi-link layer. I-link layer ine-Maximum Transmission Unit (MTU), eyiyona packet size iphezulu enokudlula kwi-data link layer. I-maximum transmission unit idla ngokunxulumene ne-interface yonxibelelwano.
Ngoko ke yintoni umahluko phakathi kwe-MSS kunye ne-MTU?
Kwinethiwekhi zekhompyutha, uyilo lwe-hierarchical lubaluleke kakhulu kuba luqwalasela umahluko phakathi kwamanqanaba ahlukeneyo. Umaleko ngamnye unegama elahlukileyo; kumaleko wothutho, idatha ibizwa ngokuba yi-segment, kwaye kumaleko wenethiwekhi, idatha ibizwa ngokuba yi-IP packet. Ke ngoko, i-Maximum Transmission Unit (MTU) inokucingwa njengoMaximum IP packet Size enokudluliselwa ngumaleko wenethiwekhi, ngelixa i-Maximum Segment Size (MSS) yingcamango yomaleko wothutho ebhekisa kubuninzi bedatha enokudluliselwa yi-TCP packet ngexesha.
Qaphela ukuba xa ubukhulu beCandelo eliPhezulu (MSS) bukhulu kuneCandelo lokuThunyelwa eliPhezulu (MTU), ukuqhekeka kwe-IP kuya kwenziwa kwileya yenethiwekhi, kwaye i-TCP ayizukwahlulahlula idatha enkulu ibe ngamacandelo afanelekileyo ngobukhulu be-MTU. Kuya kubakho icandelo kwileya yenethiwekhi elinikezelwe kwileya ye-IP.
Ulwakhiwo lwecandelo lepakethi ye-TCP
Makhe sihlolisise ifomathi kunye nomxholo wee-headers ze-TCP.
Inombolo yolandelelwano: Inombolo engacwangciswanga eveliswa yikhompyutha xa uqhagamshelo lumiselwe njengexabiso lalo lokuqala xa uqhagamshelo lwe-TCP lumiselwe, kwaye inombolo yolandelelwano ithunyelwa kumamkeli ngepakethi ye-SYN. Ngexesha lokudluliselwa kwedatha, umthumeli unyusa inombolo yolandelelwano ngokwenani ledatha ethunyelweyo. Umamkeli ugweba ulandelelwano lwedatha ngokwenani lolandelelwano olufunyenweyo. Ukuba idatha ifunyenwe ingacwangciswanga, umamkeli uza kuyicwangcisa kwakhona idatha ukuqinisekisa ulandelelwano lwedatha.
Inombolo yokuvuma: Le yinombolo yolandelelwano esetyenziswa kwi-TCP ukuvuma ukufunyanwa kwedatha. Ibonisa inombolo yolandelelwano lwedatha elandelayo elindeleke ukuba umthumeli ayifumane. Kuqhagamshelo lwe-TCP, umamkeli umisela ukuba yeyiphi idatha efunyenwe ngempumelelo ngokusekelwe kwinani lolandelelwano lwecandelo lepakethi yedatha efunyenweyo. Xa umamkeli efumana idatha ngempumelelo, uthumela ipakethi ye-ACK kumthumeli, equlethe inombolo yokuvuma ukwamkelwa. Emva kokufumana ipakethi ye-ACK, umthumeli unokuqinisekisa ukuba idatha ngaphambi kokuvuma inombolo yempendulo ifunyenwe ngempumelelo.
Iibhithi zolawulo zecandelo le-TCP ziquka oku kulandelayo:
Iqhekeza le-ACK: Xa le bit ingu-1, oko kuthetha ukuba intsimi yempendulo yokuvuma iyasebenza. I-TCP icacisa ukuba le bit kufuneka isetelwe ku-1 ngaphandle kweepakethi ze-SYN xa uqhagamshelo luqaliswe ekuqaleni.
I-RST bit: Xa le bit ingu-1, ibonisa ukuba kukho into eyahlukileyo kuqhagamshelo lwe-TCP kwaye uqhagamshelo kufuneka lunyanzelwe ukuba luqhawulwe.
I-SYN bit: Xa le bit isetiwe kwi-1, oko kuthetha ukuba uqhagamshelo luza kusekwa kwaye ixabiso lokuqala lenombolo yolandelelwano lisetiwe kwicandelo lenombolo yolandelelwano.
Iqhekeza le-FIN: Xa le bit ingu-1, oko kuthetha ukuba akusekho datha iya kuthunyelwa kwixesha elizayo kwaye uqhagamshelo luyafuneka.
Imisebenzi eyahlukeneyo kunye neempawu ze-TCP zibonakaliswa bulwakhiwo lwamacandelo eepakethi ze-TCP.
Yintoni i-UDP? (I-Mylinking'sI-Network TapkwayeUmthengisi wePakethi yeNethiwekhiingacubungula zombini iipakethi zeTCP okanye ze-UDP)
I-User Datagram Protocol (UDP) yiprotokholi yonxibelelwano engenanxibelelwano. Xa ithelekiswa ne-TCP, i-UDP ayiboneleli ngeendlela zokulawula ezintsonkothileyo. Iprotokholi ye-UDP ivumela usetyenziso ukuba luthumele ngqo iipakethi ze-IP ezifakwe ngaphakathi ngaphandle kokuseka unxibelelwano. Xa umphuhlisi ekhetha ukusebenzisa i-UDP endaweni ye-TCP, usetyenziso lunxibelelana ngqo ne-IP.
Igama elipheleleyo le-UDP Protocol yi-User Datagram Protocol, kwaye i-header yayo yi-bytes ezisibhozo kuphela (iibhithi ezingama-64), nto leyo efutshane kakhulu. Ifomathi ye-header ye-UDP yile ilandelayo:
Indawo ekuyiwa kuyo kunye neendawo zokufumana ulwaziInjongo yabo ephambili kukubonisa ukuba i-UDP kufuneka ithumele iipakethi kweyiphi inkqubo.
Ubungakanani bepakethi: Intsimi yobungakanani bepakethi ibamba ubungakanani bentloko ye-UDP kunye nobungakanani bedatha.
I-Checksum: Yenzelwe ukuqinisekisa ukuhanjiswa okuthembekileyo kwee-headers kunye nedatha ye-UDP. Indima ye-checksum kukufumanisa ukuba kwenzeke impazamo okanye ukonakala ngexesha lokudluliselwa kwepakethi ye-UDP ukuqinisekisa ukuthembeka kwedatha.
Umahluko phakathi kwe-TCP kunye ne-UDP kwi-Mylinking'sI-Network TapkwayeUmthengisi wePakethi yeNethiwekhiingacubungula zombini iiPakethi zeTCP okanye zeUDP
I-TCP kunye ne-UDP zahlukile kwezi nkalo zilandelayo:
Uqhagamshelo: I-TCP yinkqubo yothutho ejolise kunxibelelwano efuna uqhagamshelo olumiselwe ngaphambi kokuba idatha idluliselwe. I-UDP, kwelinye icala, ayifuni uqhagamshelo kwaye inokudlulisa idatha ngoko nangoko.
Into yeNkonzo: I-TCP yinkonzo ye-one-to-one two-point, oko kukuthi, uqhagamshelo luneendawo ezimbini kuphela zokunxibelelana. Nangona kunjalo, i-UDP ixhasa unxibelelwano olusebenzisanayo lwe-one-to-one, lwe-one-to-many, kunye nolwe-many-to-many, olunokunxibelelana neehostele ezininzi ngaxeshanye.
Ukuthembeka: I-TCP ibonelela ngenkonzo yokuhambisa idatha ngokuthembekileyo, iqinisekisa ukuba idatha ayinazimpazamo, ayinalahleko, ayiphindaphindwa, kwaye ifika xa ifunwa. Kwelinye icala, i-UDP yenza konke okusemandleni ayo kwaye ayiqinisekisi ukuhanjiswa okuthembekileyo. I-UDP inokulahlekelwa yidatha kunye nezinye iimeko ngexesha lokudluliselwa.
Ulawulo lokuxinana, ulawulo lokuhamba kwamanzi: I-TCP ineendlela zokulawula ukuxinana kunye neendlela zokulawula ukuhamba kwedatha, ezinokulungisa izinga lokudluliselwa kwedatha ngokweemeko zenethiwekhi ukuqinisekisa ukhuseleko kunye nozinzo lokudluliselwa kwedatha. I-UDP ayinazo iindlela zokulawula ukuxinana kunye neendlela zokulawula ukuhamba kwedatha, nokuba inethiwekhi ixinene kakhulu, ayizukwenza hlengahlengiso kwizinga lokuthumela i-UDP.
Intloko ephezu kwentloko: I-TCP inobude bentloko ende, ngesiqhelo ingama-20 bytes, nto leyo eyandayo xa kusetyenziswa amasimi okhetho. I-UDP, kwelinye icala, inentloko esisigxina yee-bytes ezisi-8 kuphela, ngoko ke i-UDP inentloko esezantsi.
Iimeko zesicelo se-TCP kunye ne-UDP:
I-TCP kunye ne-UDP ziiprotokholi ezimbini ezahlukeneyo zomaleko wothutho, kwaye zinomahluko othile kwiimeko zokusetyenziswa.
Ekubeni i-TCP iyiprotocol ejolise kunxibelelwano, isetyenziswa kakhulu kwiimeko apho kufuneka khona ukuhanjiswa kwedatha okuthembekileyo. Ezinye iimeko eziqhelekileyo zokusetyenziswa ziquka:
Ukudluliselwa kwefayile yeFTP: I-TCP inokuqinisekisa ukuba iifayile azilahleki kwaye azinakonakala ngexesha lokudluliselwa.
I-HTTP/HTTPS: I-TCP iqinisekisa ukuthembeka nokuchaneka komxholo wewebhu.
Ngenxa yokuba i-UDP yiprotocol engenanxibelelwano, ayiboneleli ngesiqinisekiso sokuthembeka, kodwa ineempawu zokusebenza kakuhle kunye nokusebenza ngexesha langempela. I-UDP ifanelekile kwezi meko zilandelayo:
Itrafikhi ephantsi, njenge-DNS (Domain Name System)Imibuzo ye-DNS idla ngokuba ziipakethi ezimfutshane, kwaye i-UDP inokuyigqiba ngokukhawuleza.
Unxibelelwano lwemultimedia olufana nevidiyo kunye nomsindo: Kwi-multimedia transmission eneemfuno eziphezulu zexesha langempela, i-UDP inokubonelela nge-latency ephantsi ukuqinisekisa ukuba idatha inokudluliselwa ngexesha elifanelekileyo.
Unxibelelwano losasazoI-UDP ixhasa unxibelelwano oluvela kumntu omnye ukuya komnye kunye nonxibelelwano oluvela kubantu abaninzi kwaye ingasetyenziselwa ukusasaza imiyalezo yokusasaza.
Isishwankathelo
Namhlanje sifunde nge-TCP. I-TCP yinkqubo yonxibelelwano olusekwe kunxibelelwano, oluthembekileyo, olusekelwe kwi-byte-stream. Iqinisekisa ukuhanjiswa okuthembekileyo kunye nokwamkelwa kwedatha ngocwangco ngokuseka uqhagamshelo, ukuxhawulana kunye nokuvuma. I-TCP protocol isebenzisa amazibuko ukufezekisa unxibelelwano phakathi kweenkqubo, kwaye ibonelela ngeenkonzo zonxibelelwano ngqo kwiinkqubo zesicelo ezisebenza kwiihost ezahlukeneyo. Uqhagamshelo lwe-TCP luyi-duplex epheleleyo, evumela ukudluliselwa kwedatha ngaxeshanye. Ngokwahlukileyo koko, i-UDP yinkqubo yonxibelelwano engenakho uqhagamshelo, engaboneleli ngeziqinisekiso zokuthembeka kwaye ifanelekile kwezinye iimeko ezineemfuno eziphezulu zexesha langempela. I-TCP kunye ne-UDP zahlukile kwimodi yoqhagamshelo, into yenkonzo, ukuthembeka, ulawulo lokuxinana, ulawulo lokuhamba kunye nezinye izinto, kwaye iimeko zazo zesicelo nazo zahlukile.
Ixesha leposi: Disemba-03-2024
