SDH tiam thiab cov yam ntxwv

Xyoo 1985, American Lub Tebchaws Cov Qauv Qauv (Ansi) tsim kho cov khoom siv kho kho kho tshiab, tis npe nws cov khoom siv synchronous (synet). Nyob rau hauv 1986, cov txheej txheem qub ntawm SDH (Synchronous Digital Hierable tsis muaj cai rau lwm tus tab sis kuj rau lwm cov ntaub ntawv xa tawm xws li microwave thiab lub satellite.

SDH tus ncej qauv kov yeej qhov tsis txaus ntseeg ntawm PDH. Piv nrog tsoos PDH, SDH muaj cov yam ntxwv zoo li nram no:

(1) yooj yim ntxiv / poob muaj nuj nqi. SDH qhia cov qauv qhia nruj thiab cov hau kev ntau yam thiab ua tiav cov pointer technology. Ceg Npe Cov cim yuav hloov tau lossis tshem tawm ncaj qha los ntawm cov cim taw qhia tsis tas yuav muaj kev ntxiv / poob cov haujlwm thiab muab cov khoom siv piv rau cov qauv network.

(2) Muaj zog tswj hwm network muaj peev xwm. SDH tus ncej qauv muaj cov khoom siv ua haujlwm txaus, uas tsis yog ua tau raws li cov kev ua tau zoo tam sim no, thiab tseem muaj kev sib txuas lus ntxiv rau kev soj ntsuam ntxiv mus ntsib kev soj ntsuam yav tom ntej thiab kev tswj hwm kev tswj hwm kev tswj hwm.

(3) Tus kheej muaj zog-} kho cov peev xwm. SDH Kev Tswj Xyuas Network nrog cov tswv yim zoo nrhiav tau thiab siv zog ua haujlwm rau SDH network kom ua tiav tus kheej yooj yim-}} mob. Thaum cov khoom siv lossis cov tshuab ua tsis tiav, kev pabcuam tuaj yeem rov qab tau sai, txhim kho kev pab txhawb nqa thiab txo tus nqi kho.

(4) SDH muaj cov qauv tsim kho kho qhov muag. Cov khoom siv los ntawm cov chaw tsim khoom sib txawv tuaj yeem cuam tshuam ntawm txoj kev kho qhov muag, tiag tiag paub txog kab rov tav kab rov tav.

(5) SDH muaj kev sib raug zoo. Stm-1 ntawm SDH tsis tuaj yeem tsuas yog motx 2 lub hau / s series pdh cim, kev sib tham thoob ntiaj teb sib cuam tshuam thiab kev hloov pauv kev yooj yim los ntawm pdh rau sdh.

Hauv cov ntsiab lus, cov yam ntxwv tseem ceeb ntawm SDH yog: synchronous multiplexing, txuj ci tsim kho qhov muag, thiab muaj peev xwm tswj hwm network.

Ntawm chav kawm, SDH Technology tsis zoo meej; Nws tseem muaj qee qhov shortcomics:

(1) Vim tias muaj ntau tus neeg siv nyiaj siv ua haujlwm, nws Bandwidth siv tsis yog li ntawm PDH;

(2) nws excts software software. Thaum lub computer ua haujlwm tsis zoo lossis yog kev tswj hwm thiab tswj hwm SDH network, thiab muaj cov xwm txheej hnyav, nws yuav ua rau cov network los tsoo;

(3) Yuav kom tau tshaj nrog ntau cov cim tseg thiab ua tiav cov kab rov tav kev txuas, tsim kho cov lus qhia ntxiv thiab ua rau qee qhov kev puas tsuaj loj rau cov cim.