Ukuthembeka ukuthembeka kwi-TCP
Sonke siqhelene nomgaqo we-TCP njengomgaqo onokuthenjwa wokuhamba, kodwa iqinisekisa njani ukuthembeka kothutho?
Ukufezekisa usulelo oluthembekileyo, izinto ezininzi kufuneka ziqwalaselwe, ezinje ngorhwaphilizo lwedatha, ilahleko, ukuphindwa, kunye noku-oda nge-oda. Ukuba ezi ngxaki azinakusonjululwa, ukuthunyelwa okuthembekileyo akunakuphunyezwa.
Ke ngoko, i-TCP isebenzisa iindlela ezinje ngenombolo yokulandelelana, ukuphendula iMvume, iPhenda, uLawulo loQhagamshelo, kunye noLawulo lweWindows ukuze ulawule usulelo oluthembekileyo.
Kweli phepha, siya kugxila kwifestile yokutyibilika, ulawulo lokuhamba kunye nokuxinana kwe-TCP. Indlela yokubonelela kwakhona igubungele ngokwahlukeneyo kwicandelo elilandelayo.
Ulawulo lokuhamba kwenethiwekhi
Ulawulo lokuhamba kwenethiwekhi okanye ukwazi njengolawulo lwendlela yenethiwekhi kuyinto ebonakalayo yobudlelwane obufihlakeleyo phakathi kwabavelisi kunye nabathengi. Kusenokwenzeka ukuba uza kule meko ininzi emsebenzini okanye kudliwanondlebe. Ukuba umthamo womvelisi wokuvelisa kakhulu ungaphezulu komsebenzi womthengi wokutya, kuya kubangela ukuba umgca ukhule ngonaphakade. Kwimeko ebaluleke kakhulu, unokwazi ukuba xa imiyalezo yoMvundla ityhala kakhulu, inokubangela ukonakaliswa kwentsebenzo ye-MQ. Kukwanjalo nange-TCP; Ukuba ishiywe ingaphenjwanga, imiyalezo emininzi iya kufakwa kwinethiwekhi, kwaye abathengi baya kudlula isikhundla sabo, ngelixa abavelisi baya kuqhubeka nokuthumela imiyalezo ephindwe kabini, eya kuthi ichaphazele kakhulu ukusebenza kwenethiwekhi.
Ukujongana nale nto, i-TCP ibonelela ngendlela yomthumeli ukulawula isixa sedatha esithunyelwe ngokusekwe kubungakanani bokwamkelwa komsebenzi womamkeli, owaziwa njengolawulo lokuhamba. Umamkeli ugcina iwindow yam, ngelixa umthumeli egcina iwindow yokuthumela. Kufuneka kuqatshelwe ukuba ezi windows ziququzelelene noqhagamshelo olunye lwe-TCP kwaye ayizizo zonke uxhulumanweni zabelana ngefestile.
I-TCP ibonelela ngolawulo lokuhamba usebenzisa umahluko kwifestile yokufumana. Ifestile efunyenweyo inika umthumeli uphawu lokuba yimalini i-cache isakhona. Umthumeli ulawula inani ledatha ethunyelwe ngokomthamo owamkelayo.
Umamkeli wamamkeli wazisa umthumeli wobukhulu bedatha enokwafunyanwa kuyo, kwaye umthumeli ethumela lo mda. Lo mda ngusayizi wefestile, khumbula isihloko se-TCP? Kukho intsimi yewindows, esetyenziselwa ukubonisa inani lee-Byte Amkeli okanye ukuvuma ukufumana.
Umniningikazi othunyelweyo uya kuthumela amaxesha ngamaxesha ukuthumela ipakethi yefestile yefestile, esetyenziselwa ukufumana ukuba umnini-mamkeli aluphi na umamkeli uyakwazi ukwamkela idatha. Xa i-buffer yomtshato isengozini yokuphuphuma, ubungakanani befestile busekwe kwixabiso elincinci ukufundisa umthumeli ukuba balawule inani ledatha ethunyelwe.
Nantsi umzobo wokulawula ukuhamba kwenethiwekhi:
Ulawulo lokuCoca
Ngaphambi kokuqalisa ukulawulwa kokuxinana, kufuneka siqonde ukuba ukongeza kwifestile yokufumana iwindows kunye nefestile yokuthumela, kukho iwindow eninzi, esetyenziswa ikakhulu ukusombulula ingxaki yokuthumela idatha kwifestile yokufumana ifestile kwifestile ye-windows. Ke ngoko, iwindows yokuxinana ikwagcinwa nguMfundi we-TCP. Sifuna i-algorithm ukuba ithathe isigqibo sokuba ingakanani idatha efanelekileyo yokuthumela, kuba idatha encinci kakhulu okanye ininzi kakhulu ayilungile, ngenxa yoko le nto yefestile yefestile.
Kulawulo lokuhamba kwenethiwekhi yangaphambili, oko sikuthintelayo kwakungumthumeli ngokuzalisa i-cache yomamkeli ngedatha, kodwa sasingazi ukuba kwenzeka ntoni kwinethiwekhi. Ngokwesiqhelo, uthungelwano lweekhompyuter zikwindawo ekwabelwana ngayo. Ngenxa yoko, kunokubakho ukuxinana kwenethiwekhi ngenxa yonxibelelwano phakathi kwezinye izinto eziziinkomfa.
Xa inethiwekhi ihlangatyezwa, ukuba inani elikhulu leepakethi liyaqhubeka ukuthunyelwa, kunokubangela iingxaki ezinjengokulibaziseka nokuphulukana neepakethi. Okwangoku, i-TCP iya kuyirhoxisa idatha, kodwa ukubuyiselwa kwakhona kuya kwandisa umthwalo kwinethiwekhi, okukhokelela kulibaziseko olukhulu kunye nelahleko yepakethi engaphezulu. Oku kungangena kumjikelezo ombi kwaye uqhubeke ufumana omkhulu.
Ke, i-TCP ayinakho ukungahoyi okwenzekayo kwinethiwekhi. Xa inethiwekhi ixineneyo, idini idini ngokwakho ngokunciphisa inani ledatha ethumela.
Ke ngoko, ulawulo lwabantu luyacetywayo, olujolise ekuphepheni ukugcwalisa inethiwekhi yonke kunye nedatha kumthumeli. Ukulawula inani ledatha Umthumeli kufuneka uthumele, i-TCP ichaza umxholo obizwa ngokuba yiwindows yokuxinana. I-Algorithm yokulawula i-algorithm iya kulungelelanisa ubungakanani befestile yokuxinana ngokwenqanaba lenethiwekhi, ukuze kulawulwe inani ledatha elithunyelwe ngumthumeli.
Yintoni iwindows yokuxinana? Yintoni le nto yenziwe ngefestile yokuthumela?
Iwindows yokuxinana iguquguqukayo igcinwe ngumthumeli echaza ubungakanani bedatha abanokuthumela umthumeli. Iwindows yokuxinana itshintsha ngokulinganayo kwinqanaba lokuxinana kwenethiwekhi.
Ifestile yokuthunyelwa yi-Window ekuvunyelwene ngayo kwi-Window kunye noMmeli obonisa ubungakanani bedatha abanokufunyanwa ngumamkeli. Ifestile yokuxinana kunye nefestile yokuthumelo zihambelana; Ifestile yokuthunyelwa ihlala ilingana nobuncinci bengqungquthela kunye nokufumana iifestile, oko kukuthi, Swew = Min (CWND).
I-COLOFT Window CWNT SUPY YOKUGQIBELA:
Ukuba akukho nto ininzi kwinethiwekhi, okt, akukho xesha lokungeniswa kwenzeka, i-conssion inyuka.
Ukuba kukho ukuxinana kwinethiwekhi, i-Colkos iwindows incipha.
Umthumeli uchaza ukuba inethiwekhi ixinekile ngokujonga ukuba iPakethi ye-ACK ifunyenwe ngaphakathi kwexesha elichaziweyo. Ukuba umthumeli akafumani ipakethi ye-ACK ACDSGGment ngexesha elichaziweyo, ithathelwa ingqalelo ukuba inethiwekhi idityaniswe.
Ukongeza kwifestile yokuxinana, lixesha lokuxoxa nge-TCP yokulawula i-algorithm. I-TCP yokuConga i-Algorithm inamacandelo amathathu aphambili:
QAPHELA UKUQALA:Ekuqaleni, iwindows yokuxinana kwe-CWRD incinci, kwaye umthumeli unyusa i-CANISS Window ngokubonakalayo ukuba ilungelelaniswe ngokukhawuleza isikhundla senethiwekhi.
Ukuxinana kokuthintelwa:Emva kokuba iwindows yengxinano idlula i-windows ethile, umthumeli unyusa iwindow yokuxinana kwi-intanethi indlela yokuthoba inqanaba lokukhula kwefestile ye-Colving kwaye uphephe ukulayisha inethiwekhi.
Ukubuyela ngokukhawuleza:Ukuba ukuxinana kwenzeka, umthumeli uyayihlutha iwindow ye-Colkos kwaye ingena kwi-Recale Reture Recale Recale ukumisela indawo yokubuyela kwakhona kwenethiwekhi nge-covericate efunyenweyo.
Qala kancinci
Xa uqhagamshelo lwe-TCP lusekiwe, i-COLDS Window Cwnd iqala kakhulu kwi-MSS encinci (ubukhulu becala ephezulu). Ngale ndlela, ireyithi yokuqala yokuthumela imalunga ne-MSS / RTT Byte / yesibini. Eyona bandwidth ekhoyo ihlala inkulu kakhulu kune-MSS / rtt, ke i-TCP ifuna ukufumana inqanaba lokuthumela ngokugqibeleleyo, elinokufezekiswa ngokuqalisa kancinci.
Kwinkqubo yokuqalisa ngokucothayo, ixabiso le-COWND CWND iya kuqalwa kwi-1 i-MSS, kwaye ixesha ngalinye livunyiwe yi-MSS enye, oko kukuthi, ixabiso le-CWLD liya kuba yi-2 mss. Emva koko, ixabiso le-CWND liphindwe kabini kulwelo ngalunye lwepakethi yepakethi, njalo njalo. Inkqubo ethile yokukhula iboniswe kweli nani lilandelayo.
Nangona kunjalo, inqanaba lokuthumela alinakuhlala likhula; Ukukhula kufuneka kuphele ngamanye amaxesha. Ke, ireyithi yokuthumela inyuka nini? Isiqalo esihamba kancinci siphela ngokunyuka kwinqanaba lokuthumela kwinye yeendlela ezininzi:
Indlela yokuqala yimeko yelahleko yepakethi ngexesha lokuthumela ngokuqalisa. Xa ilahleko yepakethi yenzeka, i-TCP icwangcisa i-windows yokuxinana yomthendeleko ye-CWND ukuya kwi-1 kwaye iqale inkqubo yokuqalisa kancinci. Okwangoku, ingcinga yokuqalisa kancinci i-SSTHrere isaziswa, ixabiso lakhe lokuqala sisiqingatha sexabiso le-CWND evelisa ilahleko yepakeji. Oko kukuthi, xa uxinaniso ufunyenwe, ixabiso le-SSTHRIS liyisiqingatha sexabiso lefestile.
Indlela yesibini kukunxibelelana ngokuthe ngqo ngexabiso lomqobo oqaqambileyo we-ssthresi. Ukusukela ukuba ixabiso le-SSTHERIS liyisiqingatha sexabiso lefestile xa ilahleko ilahleko, ilahleko yepakethi inokwenzeka ngokuphindaphindiweyo xa i-CWND inkulu kune-SSTHHER. Ke ngoko, kungcono ukuseta i-CWD kwi-SSTHRIS, eya kubangela ukutshintshela kwimodi yolawulo kunye nokuphela kokuqala.
Indlela yokugqibela ehamba kancinci ingapheli ukuba ii-acks ezintathu ezingafunekiyo zifunyenwe, i-TCP isebenza ngokukhawuleza kwaye ingena kwi-Retustal State. (Ukuba ayicacanga ukuba kutheni kukho iipakethi ezintathu ze-ACK, iya kuchazwa ngokwahlukeneyo kwindlela yokubuyisela kwakhona.)
Ukuxinana kokuthintelwa
Xa i-TCP ingena kwi-Coldeonation State Commol, i-CWD isekwe kwisiqingatha somqobo wokuhlambela i-ssthresi. Oku kuthetha ukuba ixabiso le-CWHD alinakuphindwa kabini ngalo lonke ixesha iqhekeza lepakethi lifunyenwe. Endaweni yoko, indlela yokwenzela ilondolozwe iyamkelwa apho ixabiso le-CWLD linyuswe yi-MSS enye (ubude bepakethi ephezulu) emva kokuba kugqityiwe ukuthunyelwa nganye. Umzekelo, nokuba amacandelo ali-10 ePacket amkelweyo, ixabiso le-CWND liya kwanda kuphela kwi-MSS enye. Le yimodeli yokukhula komgca kwaye ikwakhutshelwe phezulu ekukhuleni. Xa ilahleko yepakethi yenzeka, ixabiso le-CWND litshintshelwe kwi-MSS, kwaye ixabiso le-SSTHRIS libekwe kwisiqingatha se-CWLD. Okanye iyakuyeka ukukhula kwe-MSS xa kufunyenwe iimpendulo ezi-3. Ukuba iimbovane ezintathu ezingafunekiyo zisafunyanwa emva kokuchitha ixabiso le-CWND, ixabiso le-SSTHRURreres lirekhodwa njengesiqingatha sexabiso le-CWND kunye nemeko yokubuyisela ngokukhawuleza ingeniswa.
Ukubuyela ngokukhawuleza
Kwimeko yokubuyisela ngokukhawuleza, ixabiso le-COLDS Window inyuke nge-MSS enye ye-ACS enye ifunyenwe i-ACTA i-ACD, oko kukuthi, i-ack engalandeli ngokulandelelana. Oku kukwenza ukusetyenziswa kwamacandelo epakethi edluliselwe ngempumelelo kwinethiwekhi ukuphucula ukusebenza kakuhle kokudluliselwa kangangoko kunokwenzeka.
Xa i-ack ye-ack yecandelo lepakethi elahlekileyo ifika, i-TCP inciphisa ixabiso le-CWND kwaye ingena kwimo yokuxinana. Oku kukulawula ubungakanani befestile yokuxinana kwaye uphephe ukwandisa ngakumbi inkohliso yenethiwekhi.
Ukuba ixesha lokuphuma kwenzeka emva kolawulo lokulawula, imeko yenethiwekhi iba nzima kwaye i-TCP ifudukela kwi-Colssing Toint Station State State. Kule meko, ixabiso le-COLDS Window CWND isetiwe kwi-1 MSS, ubude bepakethi ephezulu, kunye nexabiso lomjelo wokuqala wokuqalisa i-SSTHress usekwe kwisiqingatha se-CWLD. Injongo yoku kukuphinda unyuse ubungakanani befestile yokuxinana emva kokuba inethiwekhi iphinda ilungelelanise inqanaba lokuhambisa kunye nenqanaba lenethiwekhi.
Isishwankathelo
Njengomgaqo oqinisekileyo wokuThutha, i-TCP isebenzisa ukuthutha okunokuthenjwa ngenani lokulandelelana, ukuvuma, uLawulo lokuPhumela, uLawulo loQhagamshelo kunye noLawulo lweWindoyini. Phakathi kwazo, indlela yokulawula ukuhambahamba ilawula inani ledatha elithunyelwe ngumthumeli ngokoqobo ngokwenyani yomthamo, othintela iingxaki zokuxinana kwenethiwekhi kunye nokupheliswa kwentsebenzo. Indlela yokulawula iColiwe kuthintela ukuvela kwenethiwekhi yokuxinana ngolungelelwaniso lwedatha ethunyelwe ngumthumeli. Iikhonsepthi zefestile yokuxinana nokuthumela i-Window zihambelana nomnye, kwaye isixa sedatha kumthumeli silawulwa ngokulungelelanisa ubungakanani befestile yokuxinana. QAPHELA UKUQALA, UKUQHUTYELWA KWAKHONA KUNYE NOKUHLAZIYWA KWEEMPAWU ZESITHATHU ZE-TCP CANSINTM INOLGGODM, ehlengahlengisa ubukhulu befestile ye-Colving kwizicwangciso zonxibelelwano.
Kwicandelo elilandelayo, siya kuhlolisisa indlela ye-TCP ye-TCP. Indlela yokubuyisela kwakhona yinxalenye ebalulekileyo ye-TCP yokufezekisa usulelo oluthembekileyo. Iqinisekisa ukuhanjiswa okuthembekileyo kwedatha ngokubuyisa i-Reffetmet, elonakalisiweyo liyincomekayo. UMGAQO-NKQUBO WOKUSETYENZISWA KOMGAQO-NKQUBO WOKUGQIBELA WOKUGQIBELA WOKUZILWAZI kwaye uhlaziywe ngokweenkcukacha kwicandelo elilandelayo. Hla umamele!
IXESHA LOKUQALA: NgoFebwe-24 ukuya ku-2425
