X.25 yog qhov kev sib txuas lus kev sib tham suite ntawm kev xaiv hauv xyoo 1980s
X.25 yog ib chav suite ntawm cov txheej txheem siv rau kev sib txuas lus-kev sib txuas lus thoob lub network-thoob plaws- WAN . Ib qho pov thawj yog ib qho kev pom zoo-raws li cov txheej txheem thiab cov cai. Ob qho khoom siv uas ua raws li tib cov kev cai muaj peev xwm to taub ib leeg thiab sib pauv cov ntaub ntawv.
Keeb Kwm ntawm X.25
X.25 tau tsim nyob rau xyoo 1970s kom muaj suab nrov dhau analog tus xov tooj-kev sib txuas lus-thiab yog ib qhov kev pab cuam tshaj plaws ntawm cov pob ntawv hloov tshiab. Cov kev siv Xias ntawm X.25 nrog cov kev sib txuas ntawm lub cav tsis siv wires thiab cov credit card authentication networks. X.25 kuj tau txais kev txhawb nqa ntau hom kev siv lub tshuab dav dav thiab daim ntawv thov kev pab. Cov 1980s yog cov hydraulic ntawm X-25 technology thaum nws siv los ntawm cov ntaub ntawv rau pej xeem cov ntaub ntawv Compuserve , Tymnet, Telenet, thiab lwm tus. Nyob rau thaum ntxov 90s, ntau X.25 networks tau hloov los ntawm Kev Tawm Tsam Txuj Ci hauv Teb Chaws Asmeskas Qee cov laus cov pej xeem siv sab nraum Teb Chaws Asmeskas siv X.25 mus txog thaum nyuam qhuav. Feem ntau cov tes hauj lwm uas ib zaug X.25 tam sim no siv qhov Internet Protocol tsis yooj yim. X-25 tseem siv nyob rau hauv qee lub ATM thiab cov credit card authentication tes hauj lwm.
X-25 Qauv
Txhua pob X.25 muaj nyob rau ntawm 128 bytes ntawm cov ntaub ntawv. Lub X.25 network ua ke muab pob ntawv sib txuam rau ntawm qhov chaw twj, qhov khoom thauj, thiab lub reassembly ntawm qhov chaw uasi. X.25 pob ntawv xa cov ntaub ntawv tso cai tsis yog hloov kev sib txuas lus thiab network-txheej kev tab sis tseem yuam kev kuaj thiab retransmission logic yuav tsum yog kev xaib tsis tuaj. X.25 tau txais kev sib txuas lus sib txuam sib luag ntawm multiplexing packets thiab siv kev sib txuas lus virtual.
X-25 muaj peb theem ntawm cov txheej txheem:
- Lub cev sab nraud
- Cov ntaub ntawv txuas lus
- Pob ntawv txheej
X-25 tshaj qhov OSI Reference Model , tab sis cov X-25 txheej yog qhov sib npaug ntawm cov txheej txheej, cov ntaub ntawv txuas txheej thiab txheej txheej ntawm OSI qauv .
Nrog rau kev pom zoo hauv Internet Protocol (IP) raws li tus txheej txheem rau cov neeg siv tes hauj lwm, X.25 cov kev siv mus rau pheej yig dua siv IP raws li txheej txheem txheej txheej network thiab hloov cov txheej sab nrauv ntawm X.25 nrog Ethernet lossis nrog cov khoom siv tshiab ATM .