Namuhla, sizoqala ngokugxila ku-TCP. Ngaphambilini esahlukweni sokufaka izingqimba, sikhulume ngephuzu elibalulekile. Esingqimbeni senethiwekhi nangaphansi, kukhulunywa kakhulu ngokuxhumeka kwe-host kuya ku-host, okusho ukuthi ikhompyutha yakho idinga ukwazi ukuthi ikuphi enye ikhompyutha ukuze ixhumeke kuyo. Kodwa-ke, ukuxhumana kunethiwekhi kuvame ukuba ukuxhumana phakathi kwezinqubo kunokuxhumana phakathi kwemishini. Ngakho-ke, iphrothokholi ye-TCP yethula umqondo we-port. I-port ingathathwa yinqubo eyodwa kuphela, enikeza ukuxhumana okuqondile phakathi kwezinqubo zohlelo lokusebenza ezisebenza kuma-host ahlukene.
Umsebenzi wengqimba yokuthutha ukuthi ungahlinzeka kanjani ngezinsizakalo zokuxhumana eziqondile phakathi kwezinqubo zohlelo lokusebenza ezisebenza kuma-host ahlukene, ngakho-ke yaziwa nangokuthi iphrothokholi yokuphela kokuphela. Ingqimba yokuthutha ifihla imininingwane eyinhloko yenethiwekhi, okuvumela inqubo yohlelo lokusebenza ukuthi ibone sengathi kukhona isiteshi sokuxhumana esinengqondo sokuphela kokuphela phakathi kwezinhlaka ezimbili zokuthutha.
I-TCP imele i-Transmission Control Protocol futhi yaziwa njenge-protocol egxile ekuxhumaneni. Lokhu kusho ukuthi ngaphambi kokuba uhlelo lokusebenza olulodwa luqale ukuthumela idatha kolunye, izinqubo ezimbili kufanele zenze i-handshake. I-Handshake inqubo exhumene ngokunengqondo eqinisekisa ukudluliselwa okuthembekile kanye nokwamukelwa kwedatha ngokuhlelekile. Ngesikhathi se-handshake, kwakhiwa uxhumano phakathi komthombo kanye nabasingathi bendawo ngokushintshana uchungechunge lwamaphakethe okulawula kanye nokuvumelana ngemingcele nemithetho ethile ukuqinisekisa ukudluliselwa kwedatha okuphumelelayo.
Kuyini i-TCP? (Ukuxhumanisa kwamiUkuthepha KwenethiwekhifuthiUmthengisi Wephakethe Lenethiwekhiingacubungula amaphakethe e-TCP noma e-UDP)
I-TCP (i-Transmission Control Protocol) iyiphrothokholi yokuxhumana kwezendlalelo zokuthutha egxile ekuxhumaneni, ethembekile, esekelwe ku-byte-stream.
Kugxile ekuxhumaneni: Ukuxhumana okugxile ekuxhumaneni kusho ukuthi ukuxhumana kwe-TCP kuwukuxhumana komuntu oyedwa, okungukuthi, ukuxhumana okuqondile kusukela ekuqaleni kuze kube sekupheleni, ngokungafani ne-UDP, engathumela imiyalezo kubabungazi abaningi ngesikhathi esisodwa, ngakho ukuxhumana komuntu oyedwa kuya kwabaningi akukwazi ukufezwa.
Okuthembekile: Ukuthembeka kwe-TCP kuqinisekisa ukuthi amaphakethe alethwa ngokuthembekile kumamukeli kungakhathaliseki ukuthi kukhona izinguquko kusixhumanisi senethiwekhi, okwenza ifomethi yephakheji yephrothokholi ye-TCP ibe yinkimbinkimbi kakhulu kuneye-UDP.
Kususelwa ekusakazweni kwe-Byte: Uhlobo lwe-TCP olusekelwe ku-byte-stream luvumela ukudluliswa kwemiyalezo yanoma yiluphi usayizi futhi luqinisekisa ukuhleleka kwemilayezo: noma ngabe umlayezo wangaphambilini awukamukelwa ngokugcwele, futhi noma ngabe ama-byte alandelayo amukelwe, i-TCP ngeke iwalethe kusendlalelo sesicelo ukuze icutshungulwe futhi izolahla ngokuzenzakalelayo amaphakethe aphindaphindiwe.
Uma i-host A kanye ne-host B sezisungule uxhumano, uhlelo lokusebenza ludinga ukusebenzisa umugqa wokuxhumana obonakalayo ukuthumela nokwamukela idatha, ngaleyo ndlela kuqinisekiswe ukudluliswa kwedatha. Iphrothokholi ye-TCP inesibopho sokulawula imisebenzi efana nokusungulwa koxhumano, ukunqanyulwa, kanye nokubamba. Kufanele kuqashelwe ukuthi lapha sithi umugqa obonakalayo usho kuphela ukusungula uxhumano, uxhumano lwephrothokholi ye-TCP lubonisa kuphela ukuthi izinhlangothi zombili zingaqala ukudluliswa kwedatha, kanye nokuqinisekisa ukuthembeka kwedatha. Ama-node okuhambisa kanye nokuthutha aphathwa amadivayisi enethiwekhi; iphrothokholi ye-TCP ngokwayo ayithinteki ngale mininingwane.
Ukuxhumeka kwe-TCP kuyisevisi egcwele i-duplex, okusho ukuthi i-host A kanye ne-host B zingadlulisela idatha kuzo zombili izinhlangothi kuxhumano lwe-TCP. Okusho ukuthi, idatha ingadluliselwa phakathi kwe-host A kanye ne-host B ngokugeleza kwe-bidirectional.
I-TCP igcina idatha okwesikhashana ku-send buffer yokuxhumana. Le send buffer ingenye yezinqolobane ezibekwe ngesikhathi sokuxhawulana ngezindlela ezintathu. Ngemuva kwalokho, i-TCP izothumela idatha ku-send cache ku-receive cache ye-host yendawo ngesikhathi esifanele. Empeleni, untanga ngamunye uzoba ne-send cache kanye ne-receive cache, njengoba kuboniswe lapha:
I-send buffer iyindawo yenkumbulo egcinwa ukusetshenziswa kwe-TCP ohlangothini lomthumeli esetshenziselwa ukugcina okwesikhashana idatha ezothunyelwa. Uma ukuxhawulana okunezindlela ezintathu kwenziwa ukuze kusungulwe uxhumano, i-send cache iyasethwa futhi isetshenziswe ukugcina idatha. I-send buffer ilungiswa ngokuguquguqukayo ngokuya ngokuxinana kwenethiwekhi kanye nempendulo evela kumamukeli.
I-receive buffer yindawo yenkumbulo egcinwa ukusetshenziswa kwe-TCP ohlangothini lokwamukela olusetshenziselwa ukugcina idatha etholiwe okwesikhashana. I-TCP igcina idatha etholiwe ku-receive cache bese ilinda uhlelo lokusebenza oluphezulu ukuthi luyifunde.
Qaphela ukuthi usayizi we-send cache kanye ne-receive cache unqunyelwe, uma i-cache igcwele, i-TCP ingase isebenzise amanye amasu, njengokulawula ukuminyana, ukulawula ukugeleza, njll., ukuqinisekisa ukudluliswa kwedatha okuthembekile kanye nokuqina kwenethiwekhi.
Kumanethiwekhi ekhompyutha, ukudluliswa kwedatha phakathi kwama-host kwenziwa ngokusebenzisa izingxenye. Ngakho-ke iyini ingxenye yephakethe?
I-TCP idala ingxenye ye-TCP, noma ingxenye yephakethe, ngokuhlukanisa ukusakaza okungenayo kube yizicucu nokwengeza izihloko ze-TCP ku-chunk ngayinye. Ingxenye ngayinye ingadluliselwa kuphela isikhathi esilinganiselwe futhi ayikwazi ukudlula usayizi we-Maximum Segment Size (MSS). Lapho ihla, ingxenye yephakethe idlula ku-link layer. I-link layer ine-Maximum Transmission Unit (MTU), okuyisayizi yephakethe ephezulu engadlula ku-data link layer. I-maximum transmission unit ivame ukuhlotshaniswa ne-interface yokuxhumana.
Ngakho-ke umehluko phakathi kwe-MSS ne-MTU uyini?
Kumanethiwekhi ekhompyutha, ukwakheka kwesigaba kubaluleke kakhulu ngoba kubheka umehluko phakathi kwamazinga ahlukene. Isendlalelo ngasinye sinegama elihlukile; kusendlalelo sokuthutha, idatha ibizwa ngokuthi i-segment, kanti kusendlalelo senethiwekhi, idatha ibizwa ngokuthi i-IP packet. Ngakho-ke, i-Maximum Transmission Unit (MTU) ingacatshangwa njengo-Maximum IP packet Size engadluliselwa isendlalelo senethiwekhi, kuyilapho i-Maximum Segment Size (MSS) ingumqondo wesendlalelo sokuthutha obhekisela enanini elikhulu ledatha elingadluliselwa yi-TCP packet ngesikhathi.
Qaphela ukuthi uma i-Maximum Segment Size (MSS) inkulu kune-Maximum Transmission Unit (MTU), ukuhlukaniswa kwe-IP kuzokwenziwa ku-network layer, futhi i-TCP ngeke ihlukanise idatha enkulu ibe yizigaba ezifanele usayizi we-MTU. Kuzoba nesigaba ku-network layer esinikezelwe ku-IP layer.
Isakhiwo sengxenye yephakethe le-TCP
Ake sihlole ifomethi kanye nokuqukethwe kwama-header e-TCP.
Inombolo yokulandelana: Inombolo engahleliwe ekhiqizwa yikhompyutha lapho uxhumano lusungulwa njengenani layo lokuqala lapho uxhumano lwe-TCP lusungulwa, futhi inombolo yochungechunge ithunyelwa kumamukeli ngephakethe le-SYN. Ngesikhathi sokudluliselwa kwedatha, umthumeli wandisa inombolo yochungechunge ngokwenani ledatha ethunyelwe. Umamukeli wahlulela ukulandelana kwedatha ngokwenombolo yochungechunge etholiwe. Uma idatha itholakala ingekho ohlelweni, umamukeli uzohlela kabusha idatha ukuqinisekisa ukulandelana kwedatha.
Inombolo yokuvuma: Lena inombolo yokulandelana esetshenziswa ku-TCP ukuvuma ukwamukelwa kwedatha. Ibonisa inombolo yokulandelana kwedatha elandelayo umthumeli alindele ukuyithola. Ekuxhumekeni kwe-TCP, umamukeli unquma ukuthi iyiphi idatha etholwe ngempumelelo ngokusekelwe enombolweni yokulandelana kwengxenye yephakethe ledatha etholwe. Lapho umamukeli ethola idatha ngempumelelo, uthumela iphakethe le-ACK kumthumeli, eliqukethe inombolo yokuvuma ukuvuma. Ngemva kokuthola iphakethe le-ACK, umthumeli angaqinisekisa ukuthi idatha ngaphambi kokuvuma inombolo yokuphendula itholwe ngempumelelo.
Izingcezu zokulawula zesigaba se-TCP zifaka okulandelayo:
I-ACK bit: Uma le bit ingu-1, kusho ukuthi inkambu yempendulo yokuvuma iyasebenza. I-TCP icacisa ukuthi le bit kumele isethwe ku-1 ngaphandle kwamaphakethe e-SYN lapho uxhumano luqalwa.
I-RST bit: Uma le bit ingu-1, ikhombisa ukuthi kukhona okuhlukile ekuxhumaneni kwe-TCP futhi uxhumano kumele luphoqeleke ukuthi lunqanyulwe.
I-SYN bit: Uma le bit isethwe ku-1, kusho ukuthi uxhumano luzosungulwa futhi inani lokuqala lenombolo yokulandelana lisethwe ensimini yenombolo yokulandelana.
I-FIN bit: Uma le bit ingu-1, kusho ukuthi awekho amanye amadatha azothunyelwa esikhathini esizayo futhi uxhumano luyadingeka.
Imisebenzi ehlukahlukene kanye nezici ze-TCP zivezwa yisakhiwo sezingxenye zamaphakethe e-TCP.
Kuyini i-UDP? (I-Mylinking'sUkuthepha KwenethiwekhifuthiUmthengisi Wephakethe Lenethiwekhiingacubungula amaphakethe e-TCP noma e-UDP)
I-User Datagram Protocol (UDP) iyi-protocol yokuxhumana engenakho ukuxhumana. Uma iqhathaniswa ne-TCP, i-UDP ayinikezi izindlela zokulawula eziyinkimbinkimbi. I-protocol ye-UDP ivumela izinhlelo zokusebenza ukuthi zithumele ngqo amaphakethe e-IP ahlanganisiwe ngaphandle kokusungula uxhumano. Uma unjiniyela ekhetha ukusebenzisa i-UDP esikhundleni se-TCP, uhlelo lokusebenza luxhumana ngqo ne-IP.
Igama eliphelele le-UDP Protocol yi-User Datagram Protocol, futhi i-header yayo ingama-byte ayisishiyagalombili kuphela (ama-bits angu-64), okufushane kakhulu. Ifomethi ye-header ye-UDP imi kanje:
Indawo oya kuyo kanye namachweba omthomboInhloso yabo eyinhloko ukukhombisa ukuthi i-UDP kufanele ithumele amaphakethe kuyiphi inqubo.
Usayizi wephakethe: Insimu yosayizi wephakethe ibamba usayizi wesihloko se-UDP kanye nosayizi wedatha
I-Checksum: Yakhelwe ukuqinisekisa ukulethwa okuthembekile kwama-header nedatha ye-UDP Indima ye-checksum ukuthola ukuthi kwenzeke iphutha noma ukonakala ngesikhathi sokudluliselwa kwephakethe le-UDP ukuqinisekisa ubuqotho bedatha.
Umehluko phakathi kwe-TCP ne-UDP ku-Mylinking'sUkuthepha KwenethiwekhifuthiUmthengisi Wephakethe Lenethiwekhiingacubungula amaphakethe e-TCP noma e-UDP
I-TCP ne-UDP zihlukile kulezi zici ezilandelayo:
Uxhumano: I-TCP iyiphrothokholi yezokuthutha egxile ekuxhumaneni edinga ukuthi kusungulwe uxhumano ngaphambi kokuba idatha idluliselwe. I-UDP, ngakolunye uhlangothi, ayidingi uxhumano futhi ingadlulisela idatha ngokushesha.
Into Yesevisi: I-TCP iyisevisi yamaphuzu amabili yomuntu oyedwa kuya komunye, okungukuthi, uxhumano lunezindawo ezimbili kuphela zokuxhumana. Kodwa-ke, i-UDP isekela ukuxhumana okusebenzisana komuntu oyedwa, umuntu oyedwa kuya kwabaningi, kanye nabantu abaningi, okungaxhumana nababungazi abaningi ngesikhathi esisodwa.
Ukuthembeka: I-TCP inikeza isevisi yokuletha idatha ngokwethembeka, iqinisekisa ukuthi idatha ayinamaphutha, ayinakulahleka, ayiphindaphindwa, futhi ifika lapho idingeka. Ngakolunye uhlangothi, i-UDP yenza konke okusemandleni ayo futhi ayiqinisekisi ukulethwa okuthembekile. I-UDP ingase ihlupheke ngokulahleka kwedatha nezinye izimo ngesikhathi sokudluliselwa.
Ukulawula ukuminyana, ukulawula ukugeleza: I-TCP inezindlela zokulawula ukuminyana kanye nokulawula ukugeleza, ezingalungisa izinga lokudluliswa kwedatha ngokwezimo zenethiwekhi ukuqinisekisa ukuphepha kanye nokuqina kokudluliswa kwedatha. I-UDP ayinazo izindlela zokulawula ukuminyana kanye nokulawula ukugeleza, noma ngabe inethiwekhi iminyene kakhulu, ngeke yenze izinguquko ezingeni lokuthumela i-UDP.
Ikhanda elingaphezulu: I-TCP inobude bekhanda elide, ngokuvamile amabhayithi angu-20, okwandayo uma kusetshenziswa izinkambu zezinketho. I-UDP, ngakolunye uhlangothi, inekhanda eliqinile lamabhayithi angu-8 kuphela, ngakho-ke i-UDP inekhanda elingaphansi.
Izimo Zohlelo Lokusebenza lwe-TCP kanye ne-UDP:
I-TCP ne-UDP ziyizinqubo ezimbili ezahlukene zezendlalelo zokuthutha, futhi zinomehluko othile ezimweni zohlelo lokusebenza.
Njengoba i-TCP iyiphrothokholi egxile ekuxhumaneni, isetshenziswa kakhulu ezimweni lapho kudingeka khona ukulethwa kwedatha okuthembekile. Ezinye izimo ezivamile zokusetshenziswa zifaka:
Ukudluliswa kwefayela le-FTP: I-TCP ingaqinisekisa ukuthi amafayela awalahleki futhi awonakaliswa ngesikhathi sokudlulisa.
I-HTTP/HTTPS: I-TCP iqinisekisa ubuqotho kanye nokunemba kokuqukethwe kwewebhu.
Ngenxa yokuthi i-UDP iyiphrothokholi engenakho ukuxhumana, ayinikezi isiqinisekiso sokuthembeka, kodwa inezici zokusebenza kahle kanye nesikhathi sangempela. I-UDP ifaneleka kulezi zimo ezilandelayo:
Ithrafikhi ephansi, njenge-DNS (Domain Name System): Imibuzo ye-DNS ivame ukuba amaphakethe amafushane, futhi i-UDP ingayiqeda ngokushesha.
Ukuxhumana kwe-multimedia njengevidiyo nomsindo: Ngokudluliswa kwe-multimedia okunezidingo eziphezulu zesikhathi sangempela, i-UDP inganikeza ukubambezeleka okuphansi ukuqinisekisa ukuthi idatha ingadluliselwa ngesikhathi esifanele.
Ukuxhumana kokusakaza: I-UDP isekela ukuxhumana komuntu oyedwa kuya kwabaningi kanye nokuxhumana okuningi kuya kwabaningi futhi ingasetshenziswa ekudluliseni imiyalezo yokusakaza.
Isifinyezo
Namuhla sifunde nge-TCP. I-TCP iyiphrothokholi yokuxhumana yezendlalelo zokuthutha eqondiswe ekuxhumaneni, ethembekile, esekwe ku-byte-stream. Iqinisekisa ukudluliselwa okuthembekile kanye nokwamukelwa kwedatha ngokuhlelekile ngokusungula uxhumano, ukuxhawulana kanye nokuvuma. Iphrothokholi ye-TCP isebenzisa amachweba ukufeza ukuxhumana phakathi kwezinqubo, futhi inikeza izinsizakalo zokuxhumana eziqondile zezinqubo zohlelo lokusebenza ezisebenza kuma-host ahlukene. Ukuxhumeka kwe-TCP kuyi-duplex egcwele, okuvumela ukudluliselwa kwedatha okuqondiswa ngasikhathi sinye. Ngokuphambene nalokho, i-UDP iyiphrothokholi yokuxhumana eqondiswe ngaphandle kokuxhumeka, enganikezi iziqinisekiso zokuthembeka futhi ifanele ezinye izimo ezinezidingo eziphezulu zesikhathi sangempela. I-TCP ne-UDP zihlukile kwimodi yokuxhumana, into yesevisi, ukuthembeka, ukulawula ukuminyana, ukulawula ukugeleza nezinye izici, futhi izimo zazo zohlelo lokusebenza nazo zihlukile.
Isikhathi sokuthunyelwe: Disemba-03-2024
