Iyini i-Spanning Tree Protocol?

I-Spanning Tree Protocol, ngezinye izikhathi ebizwa ngokuthi i-Spanning Tree, i-Waze noma i-MapQuest yamanethiwekhi esimanje e-Ethernet, eqondisa ithrafikhi ngomzila osebenza kahle kakhulu ngokusekelwe ezimeni zesikhathi sangempela.

Ngokusekelwe ku-algorithm eyakhiwe usosayensi wekhompyutha waseMelika u-Radia Perlman ngenkathi esebenzela i-Digital Equipment Corporation (DEC) ngo-1985, inhloso eyinhloko ye-Spanning Tree ukuvimbela izixhumanisi ezingasasebenzi kanye nokuvuleka kwezindlela zokuxhumana ekucushweni kwenethiwekhi okuyinkimbinkimbi. Njengomsebenzi wesibili, i-Spanning Tree ingakwazi ukuhambisa amaphakethe ezindaweni zezinkinga ukuze kuqinisekiswe ukuthi ukuxhumana kuyakwazi ukungena kumanethiwekhi okungenzeka ahlangabezane nokuphazamiseka.

I-Spanning Tree topology vs. Ring topology

Ngenkathi izinhlangano zisaqala ukuhlanganisa amakhompuyutha azo ngeminyaka yawo-1980, okunye ukucupha okwakudume kakhulu kwakuyinethiwekhi yeringi. Isibonelo, i-IBM yethula ubuchwepheshe bayo be-Token Ring ngo-1985.

Ku-topology yenethiwekhi eyindandatho, inodi ngayinye ixhuma nezinye ezimbili, eyodwa ehlezi ngaphambi kwayo eringini nenye ebekwe ngemuva kwayo. Amasignali azungeza iringi ngendlela eyodwa kuphela, inodi ngayinye endleleni ikhipha noma yimaphi amaphakethe azungeza iringi.

Nakuba amanethiwekhi endandatho alula esebenza kahle uma kunamakhompuyutha ambalwa kuphela, izindandatho ziye zingasebenzi kahle lapho amakhulu noma izinkulungwane zamadivayisi engezwa kunethiwekhi. Ikhompiyutha ingase idinge ukuthumela amaphakethe kumakhulu amanodi ukuze nje yabelane ngolwazi nenye isistimu eyodwa ekamelweni eliseduze. Umkhawulokudonsa kanye nokuphumayo nakho kuba yinkinga lapho ithrafikhi ikwazi ukugelezela ohlangothini olulodwa kuphela, ngaphandle kwecebo lokusekelayo uma i-node endleleni iphuka noma iminyene ngokweqile.

Ngama-90s, njengoba i-Ethernet yathola ngokushesha (i-100Mbit/sec. I-Fast Ethernet yethulwa ngo-1995) kanye nezindleko zenethiwekhi ye-Ethernet (amabhuloho, amaswishi, izintambo) zaba ishibhile kakhulu kune-Token Ring, i-Spanning Tree yanqoba izimpi ze-LAN topology kanye ne-Token. Indandatho yaphela ngokushesha.

Sisebenza Kanjani Isihlahla Esinqamulayo

[BHALISA MANJE ukuze uthole umcimbi wokugcina we-FutureIT wonyaka! I-workshop ekhethekile yokuthuthukiswa kochwepheshe iyatholakala. I-FutureIT eNew York, Novemba 8]

I-Spanning Tree iyiphrothokholi yokudlulisela phambili yamaphakethe wedatha. Iyingxenye eyodwa yephoyisa lomgwaqo kanye nengxenye eyodwa kanjiniyela wemigwaqo emikhulu yenethiwekhi lapho idatha ihamba khona. Ihlala Kusendlalelo 2 (ungqimba lwesixhumanisi sedatha), ngakho imane iphathelene nokuhambisa amaphakethe endaweni yawo efanele, hhayi ukuthi hlobo luni lwamaphakethe oluthunyelwayo, noma idatha ayiqukethe.

I-Spanning Tree isibe yonke indawo kangangokuthi ukusetshenziswa kwayo kuchazwa ku-Izinga lenethiwekhi le-IEEE 802.1D. Njengoba kuchazwe endinganisweni, indlela eyodwa kuphela esebenzayo ingaba khona phakathi kwanoma yiziphi iziphetho ezimbili noma iziteshi ukuze zisebenze kahle.

I-Spanning Tree yakhelwe ukuqeda ukuthi kungenzeka ukuthi idatha edlulayo phakathi kwamasegimenti enethiwekhi izobhajwa ku-loop. Ngokuvamile, amalophu adida i-algorithm yokudlulisela phambili efakwe kumadivayisi enethiwekhi, ikwenze ukuthi idivayisi ingasakwazi ukuthi iwathumele kuphi amaphakethe. Lokhu kungase kubangele ukuphindwaphindwa kozimele noma ukudluliselwa kwamaphakethe ayimpinda ezindaweni eziningi okuyiwa kuzo. Imilayezo ingaphindaphindwa. Ukuxhumana kungabuyela kumthumeli. Ingakwazi ngisho nokuphahlazeka inethiwekhi uma izihibe eziningi kakhulu ziqala ukwenzeka, zidle umkhawulokudonsa ngaphandle kwenzuzo encomekayo ngenkathi ivimba enye i-traffic engena-looped ukuthi idlule.

I-Spanning Tree Protocolimisa amaluphu ukuthi akhekengokuvala yonke indlela engaba khona yephakethe ngalinye ledatha. Amaswishi kunethiwekhi asebenzisa i-Spanning Tree ukuchaza izimpande namabhuloho lapho idatha ingahamba khona, futhi ngokusebenza ivale imizila eyimpinda, iyenze ingasebenzi futhi ingasebenziseki kuyilapho indlela eyinhloko itholakala.

Umphumela uba ukuthi ukuxhumana kwenethiwekhi kugeleza ngaphandle komthungo kungakhathaliseki ukuthi inethiwekhi iba yinkimbinkimbi noma enkulu kangakanani. Ngandlela thize, i-Spanning Tree idala izindlela ezingazodwa ngokusebenzisa inethiwekhi ukuze idatha ihambe kusetshenziswa isofthiwe ngendlela efanayo naleyo onjiniyela benethiwekhi ababenza ngayo besebenzisa ihadiwe kumanethiwekhi amadala we-loop.

Izinzuzo Ezengeziwe Ze-Spanning Tree

Isizathu esiyinhloko sokuthi i-Spanning Tree isetshenziswa ukuqeda amathuba okusebenzisa izihibe ngaphakathi kwenethiwekhi. Kodwa kunezinye izinzuzo futhi.

Ngenxa yokuthi i-Spanning Tree ihlale ibheka futhi ichaza ukuthi yiziphi izindlela zenethiwekhi ezitholakalayo ukuze amaphakethe edatha ahambe ngazo, ingakwazi ukubona ukuthi indawo ehlezi eduze kweyodwa yalezo zindlela eziyinhloko ivaliwe. Lokhu kungenzeka ngezizathu ezahlukahlukene kusukela ekuhlulekeni kwehadiwe kuya ekucushweni okusha kwenethiwekhi. Kungaba ngisho isimo sesikhashana esisekelwe kumkhawulokudonsa noma ezinye izici.

Uma i-Spanning Tree ithola ukuthi indlela yokuqala ayisasebenzi, ingavula ngokushesha enye indlela ebivalwe ngaphambilini. Ingakwazi ke ukuthumela idatha endaweni yenkinga, ekugcineni imise indlela echezukelayo njengendlela eyinhloko, noma ithumele amaphakethe emuva ebhulohweni langempela uma iphinda itholakala.

Ngenkathi iSihlahla Sokuqala Esiyinkaba sasishesha kakhulu ekwenzeni lokho kuxhumana okusha njengoba kudingeka, ngo-2001 i-IEEE yethula i-Rapid Spanning Tree Protocol (RSTP). Ebizwa nangokuthi inguqulo ye-802.1w yephrothokholi, i-RSTP yakhelwe ukuhlinzeka ngokululama ngokushesha okukhulu ekuphenduleni izinguquko zenethiwekhi, ukuphuma kwesikhashana noma ukwehluleka ngokuphelele kwezingxenye.

Futhi ngenkathi i-RSTP yethula izindlela ezintsha zokuziphatha zokuhlangana nezindima zembobo yebhuloho ukuze kusheshiswe inqubo, iphinde yaklanywa ukuthi ihambisane ngokugcwele ne-Spanning Tree yasekuqaleni. Ngakho-ke kuyenzeka ukuthi amadivayisi anezinguqulo zombili zephrothokholi asebenze ndawonye kunethiwekhi efanayo.

Amaphutha Esihlahla Esinwebekayo

Yize i-Spanning Tree itholakala yonke indawo eminyakeni eminingi kulandela ukwethulwa kwayo, kukhona abaphikisa ngokuthiisikhathi sesifikile. Iphutha elikhulu le-Spanning Tree ukuthi ivala izihibe ezingaba khona ngaphakathi kwenethiwekhi ngokuvala izindlela ezingaba khona lapho idatha ingahamba khona. Kunoma iyiphi inethiwekhi enikeziwe kusetshenziswa i-Spanning Tree, cishe u-40% wezindlela zenethiwekhi ezingaba khona zivaliwe kudatha.

Ezimweni zokuxhumana eziyinkimbinkimbi kakhulu, njengalezo ezitholakala phakathi kwezikhungo zedatha, ikhono lokukhula ngokushesha ukuze kuhlangatshezwane nesidingo libalulekile. Ngaphandle kwemikhawulo ebekwe yi-Spanning Tree, izikhungo zedatha zingavula umkhawulokudonsa omningi ngaphandle kwesidingo se-hardware eyengeziwe yokuxhumana. Lesi isimo esiyindida, ngoba izindawo zokuxhumana eziyinkimbinkimbi yingakho kwadalwa i-Spanning Tree. Futhi manje isivikelo esihlinzekwa yi-protocol ngokumelene ne-loping, ngandlela thile, sibambe lezo zindawo kusukela emandleni azo aphelele.

Inguqulo ecwengisisiwe yephrothokholi ebizwa ngokuthi i-Multiple-Instance Spanning Tree (MSTP) yathuthukiswa ukuze isebenzise ama-LAN abonakalayo futhi ivumele imizila eminingi yenethiwekhi ukuthi ivuleke ngesikhathi esisodwa, kuyilapho isavimbela amaluphu ukuthi akheke. Kodwa ngisho nange-MSTP, izindlela ezimbalwa zedatha ezingaba khona zihlala zivaliwe kunoma iyiphi inethiwekhi esebenzisa umthetho olandelwayo.

Kube nemizamo eminingi engajwayelekile, ezimele yokuthuthukisa imikhawulo yomkhawulokudonsa we-Spanning Tree eminyakeni edlule. Yize abaklami babanye babo bethi baphumelele emizamweni yabo, iningi labo alihambisani ngokuphelele nenqubo eyisisekelo, okusho ukuthi izinhlangano kumele zisebenzise izinguquko ezingajwayelekile kuwo wonke amadivayisi azo noma zithole indlela ethile yokuzivumela ukuthi zibe khona nazo. amaswishi asebenzisa i-Spanning Tree ejwayelekile. Ezimweni eziningi, izindleko zokunakekela nokweseka ama-flavour amaningi we-Spanning Tree aziwufanele umzamo.

Ingabe Isihlahla Esinwebekayo Sizoqhubeka Esikhathini Esizayo?

Ngaphandle kwemikhawulo yomkhawulokudonsa ngenxa ye-Spanning Tree evala izindlela zenethiwekhi, awukho umcabango omningi noma umzamo owenziwe ukuze kushintshwe umthetho olandelwayo. Nakuba i-IEEE ngezikhathi ezithile ikhipha izibuyekezo ukuze izame ukuyenza isebenze kahle, ihlezi ihlehla ihambisana nezinguqulo ezikhona zephrothokholi.

Ngomqondo othile, i-Spanning Tree ilandela umthetho othi “Uma ingaphukile, ungayilungisi.” I-Spanning Tree isebenza ngokuzimela ngemuva kwamanethiwekhi amaningi ukuze igcine ukugeleza kwethrafikhi, ivimbele amalophu adala ukuphahlazeka ukuthi angakheki, futhi ihambisa ithrafikhi ezindaweni ezinezinkinga ukuze abasebenzisi bokugcina bangaze bazi noma ngabe inethiwekhi yabo ihlangabezana yini nokuphazamiseka okwesikhashana njengengxenye yosuku nosuku- imisebenzi yosuku. Khonamanjalo, ku-backend, abalawuli bangakwazi ukwengeza amadivaysi amasha kumanethiwekhi abo ngaphandle kokucabanga kakhulu ukuthi bazokwazi yini ukuxhumana nayo yonke inethiwekhi noma umhlaba wangaphandle.

Ngenxa yakho konke lokho, kungenzeka ukuthi i-Spanning Tree izohlala isetshenziswa iminyaka eminingi ezayo. Kungase kube nezibuyekezo ezincane ngezikhathi ezithile, kodwa umnyombo we-Spanning Tree Protocol kanye nazo zonke izici ezibalulekile ezenzayo cishe zizohlala lapha.