Inethiwekhi yeCisco: Uhlobo lwe-OSI Layer 5-Session

Ngu-Edward Tetz

Uluhlu lweseshoni yeNkqubo evulekileyo yoQhagamshelo lweNkqubo (i-OSI) ichaza indlela idatha efomathiweyo ngayo phakathi kwezixhobo zalo naliphi na icala lekhonkco. Le iyindlela efanelekileyo yokugcina umjelo ovulekileyo phakathi kwezi zixhobo zimbini. Nangona kunjalo, kumanqanaba asezantsi emodeli ye-OSI, akukho nxibelwano olusisigxina kodwa ke kuthotho lweziqhushumbo ezimfutshane zedatha ethunyelwa emva naphambili.



Uluhlu lweseshoni lugcina incoko kuninzi kokuqhuma kwedatha; Ngapha koko, kunokuthatha ukugqabhuka kwedatha ukubuyela umva naphambili ukumisa ulwakhiwo oluya kulandelwa kweso seshoni.



Umzekelo wehlabathi lokwenyani womaleko weseshoni inokuba ziintlola ezimbini ezitshintshana ngemiyalezo. Kuya kufuneka baseke i-odolo yokusebenza eya kuthi isetyenziselwe ukugqithisa imiyalezo ebhaliweyo ngapha nangapha. Inkqubo yokudlulisa imiyalezo inokuqwalaselwa njengomaleko weseshini kwaye inokubandakanya amanyathelo njengokusebenzisa isivumelwano esivunyelweneyo sokufaka umyalezo.

Ukwabelana ngefayile yeWindows kunecandelo lokwahlulahlula iiseshini xa kusungulwa iiseshoni, njengoko kubonisiwe kumfanekiso olandelayo.



Injongo yekhompyuter yabathengi kulo mzobo ungezantsi kukufumana uluhlu lwezabelo kwiseva, kodwa kufuneka ilandele inkqubo yokumisela iseshoni ukuze ufumane idatha oyifunayo. Umncedisi kule nkqubo ukwimeko engapheliyo yokumamela izicelo zonxibelelwano. njengoko umthengi eqala inkqubo, inkqubo yokuseta iseshoni isebenza ngolu hlobo:

  1. Umxhasi uthumela isicelo seseshoni kwiserver.

  2. Umncedisi uyasamkela isicelo kwaye ubandakanya kulwamkelo uluhlu lwayo yonke inkqubo yeseshoni exhaswayo.



    Kwimeko yeseva yeWindows, uluhlu lubandakanya ezindala, iindlela ezingakhuselekanga ezinje nge-LANMAN, kunye neenguqulelo ze-NT LANMAN ezitsha nezikhuselekileyo ze-2 (NT LM 2).

    I-pyrantel pamoate itshathi yenqanaba lekati

    umfanekiso0.jpg

  3. Umxhasi uphonononge uluhlu lweeprotokholi ezixhasiweyo kwaye ukhethe eyona ndlela ikhuselekileyo yeseshoni.

    Okwangoku, ithumela iseva inkqubo ekhethiweyo yeseshoni abaza kuyisebenzisa kwaye bacele ukuqhuba ubunyani. Kule meko, ukuqinisekiswa kuya kuqinisekisa igama lomsebenzisi kunye negama eligqithisiweyo kwiziko ledatha le-akhawunti yomsebenzisi.

  4. Umncedisi wenza umtya ongacwangciswanga wabalinganiswa obandakanyiweyo kumceli mngeni wegama eligqithisiweyo kwaye ulithumela kumthengi.

  5. Umxhasi uthatha umtya wokucela umngeni wegama eligqithisiweyo kwaye usebenzisa elakhe igama lokugqitha njengesitshixo sokubhaliweyo ukubethela umtya ongahleliwe.

  6. Umtya obhalwe ngoku u-encrypted emva koko ubuyiselwa kwiserver kwiphakheji yokuqinisekisa ubungqina ekwabandakanya igama lomsebenzisi.

  7. Iseva ifumana iphasiwedi yomsebenzisi kwindawo yogcino lweakhawunti yomsebenzisi, kwaye isebenzisa igama eligqithisiweyo njengesitshixo sokubethela ukubethela umtya ongumlinganiswa othunyelwe kumthengi kwinyathelo lomceli mngeni (Inyathelo 4).

  8. Umncedisi uthelekisa iziphumo azibalileyo kwiziphumo ezidweliswe kwiphakheji yokuqinisekisa.

  9. Ukuba iziphumo ziyahambelana, njengoko zisenza kulo mzekeliso, ukuvuma (i-ACK) kuthunyelwa kumthengi kwaye iseshoni ngoku iyasebenza; kodwa ukuba azidibani, iserver ithumela ukuvuma okungalunganga (NACK).

    Ukuba umthengi ufumana i-NACK, iya kubuyela kwiNqanaba 3 kwaye ikhuphe isicelo esitsha sokungqinisisa.

  10. Okwangoku iseshoni isetiwe, kwaye umthengi unokwenza isicelo soluhlu lwezabelo ezikwiseva, ezinokuthi zikhokelele kwisicelo soluhlu lweefayile, kunye nemixholo yefayile ethile.

    Yonke le misebenzi yexesha elizayo iya kuqhutywa nangona iseshoni enye sele yenziwe.

Inyathelo le-10 kuluhlu olwandulelayo lubonisa utshintsho kumaleko weseshoni kunye nongqameko lwenkcazo. Kwisakhelo seseshini, ijelo lonxibelelwano kwizixhobo zeseva yeWindows lasekwa, kodwa njengoko esona sicelo sithunyelweyo kuluhlu lwezabelo ezikhoyo kwiserver, isicelo sisebenzise ishaneli yomjelo wonxibelelwano, kodwa sasihanjiswa kwintetho. maleko kwaye ekugqibeleni umaleko wesicelo seSeva yeWindows.