Ngaphandle kokusetyenziswa ngokubanzi kweenethiwekhi ze-Ethernet, itekhnoloji yonxibelelwano esekwe kwi-DSL ihlala ifanelekile nanamhlanje. Kuze kube ngoku, i-DSL inokufumaneka kwiinethiwekhi zokugqibela zokudibanisa izixhobo zokubhalisa kwi-intanethi yomnikezeli we-intanethi, kwaye kutshanje iteknoloji isetyenziselwa ukwakhiwa kwamanethiwekhi asekuhlaleni, umzekelo, kwizicelo zoshishino, apho i-DSL isebenza njengomncedisi we-Ethernet. okanye uthungelwano endle esekelwe RS-232/422/485. Izisombululo ezifanayo zemizi-mveliso zisetyenziswa ngokusebenzayo kumazwe aphuhlileyo aseYurophu naseAsia.
I-DSL yintsapho yemigangatho eyaye yakhulelwa ekuqaleni ukuhambisa idatha yedijithali kwiintambo zefowuni. Ngokwembali, yaba yeyokuqala itekhnoloji yokufikelela kwi-Intanethi, ithatha indawo ye-DIAL UP kunye ne-ISDN. Uluhlu olubanzi lwemigangatho ye-DSL ekhoyo ngoku kungenxa yokuba iinkampani ezininzi, ukuqala kwi-80s, zazama ukuphuhlisa nokuthengisa iteknoloji yazo.
Zonke ezi phuhliso zinokwahlulwa zibe ziindidi ezimbini ezinkulu - i-asymmetric (ADSL) kunye ne-symmetric (SDSL) technologies. I-Asymmetric ibhekisela kulabo apho isantya soxhulumaniso olungenayo luhluke kwisantya se-traffic ephumayo. Nge-symmetric sithetha ukuba ulwamkelo kunye nezantya zothumelo ziyalingana.
Imigangatho ye-asymmetric eyaziwa kakhulu kwaye ixhaphake, ngokwenene, i-ADSL (kwi-edition yakamuva - ADSL2 +) kunye ne-VDSL (VDSL2), i-symmetric - i-HDSL (iprofayili ephelelwe yisikhathi) kunye ne-SHDSL. Zonke zahluke omnye komnye kuba zisebenza kwii-frequencies ezahlukeneyo kwaye zisebenzisa iindlela ezahlukeneyo zekhowudi kunye neendlela zokumodareyitha kumgca wonxibelelwano lomzimba. Iindlela zokulungisa iimpazamo nazo ziyahluka, okukhokelela kumanqanaba ahlukeneyo okhuselo lwengxolo. Ngenxa yoko, iteknoloji nganye inemida yayo kwisantya kunye nomgama wokuhanjiswa kwedatha, kubandakanywa nokuxhomekeka kuhlobo kunye nomgangatho womqhubi.
Imida yemigangatho eyahlukeneyo yeDSL
Kuyo nayiphi na iteknoloji ye-DSL, izinga lokudlulisa idatha liyancipha njengoko ubude bekhebula bukhula. Kwimigama enzima kakhulu kunokwenzeka ukuba ufumane isantya samakhulu amaninzi eekhilobhi, kodwa xa uhambisa idatha ngaphezu kwe-200-300 m, isantya esiphezulu sifumaneka.
Phakathi kwazo zonke iitekhnoloji, i-SHDSL inenzuzo enkulu eyenza kube lula ukuyisebenzisa kwizicelo zemizi-mveliso-i-immunity ephezulu yengxolo kunye nokukwazi ukusebenzisa naluphi na uhlobo lomqhubi wokuhanjiswa kwedatha. Oku akunjalo ngemigangatho ye-asymmetric, kwaye umgangatho wonxibelelwano uxhomekeke kakhulu kumgangatho womgca osetyenziselwa ukuhanjiswa kwedatha. Ngokukodwa, kucetyiswa ukuba usebenzise intambo yefowuni ephothiweyo. Kule meko, isisombululo esithembekileyo kukusebenzisa ikhebula le-optical endaweni ye-ADSL kunye ne-VDSL.
Naliphi na i-conductors ehlukanisiweyo ukusuka komnye nomnye ifanelekile kwi-SHDSL - ithusi, i-aluminium, intsimbi, njl. Indawo yokuhambisa i-transmission medium ingaba iingcingo zombane ezindala, iintambo zomnxeba ezindala, i-barbed wire wire, njl.
Ukuxhomekeka kwesantya sothumelo lwedatha ye-SHDSL kumgama kunye nohlobo lomqhubi
Ukusuka kwigrafu yesantya sokudlulisa idatha ngokubhekiselele kumgama kunye nohlobo lomqhubi onikezelwe kwi-SHDSL, unokubona ukuba abaqhubi abanecandelo elikhulu elinqamlezayo bakuvumela ukuba udlulise ulwazi kumgama omkhulu. Ngombulelo kwitheknoloji, kunokwenzeka ukuququzelela unxibelelwano kumgama ukuya kwi-20 km ngesantya esiphezulu se-15.3 Mb / s kwi-2-wire cable okanye i-30 Mb kwi-4-wire cable. Kwizicelo zokwenyani, isantya sothumelo sinokusetwa ngesandla, esiyimfuneko kwiimeko zokuphazamiseka okunamandla kombane okanye umgangatho ombi womgca. Kule meko, ukwandisa umgama wokudlulisa, kuyimfuneko ukunciphisa isantya sezixhobo ze-SHDSL. Ukubala ngokuchanekileyo isantya ngokuxhomekeke kumgama kunye nodidi lomqhubi, ungasebenzisa isoftware yasimahla efana ne .
Kutheni i-SHDSL ine-immunity ephezulu yengxolo?
Umgaqo-nkqubo wokusebenza we-transceiver ye-SHDSL unokumelwa ngendlela ye-block diagram, apho inxalenye ethile kunye nokuzimela (engaguqukiyo) ukusuka kwindawo yokujonga isicelo iyahlukaniswa. Icandelo elizimeleyo liqukethe i-PMD (i-Physical Medium Dependent) kunye ne-PMS-TC (i-Physical Medium-Specific TC Layer) iibhloko ezisebenzayo, ngelixa inxalenye ethile ibandakanya i-TPS-TC (i-Transmission Protocol-Specific TC Layer) kunye nedatha yomsebenzisi.
Ikhonkco elibonakalayo phakathi kwee-transceivers (STUs) linokubakho njengeperi enye okanye iintambo ezininzi. Kwimeko yeentambo ezininzi zeentambo, i-STU iqulethe ii-PMD ezininzi ezizimeleyo ezinxulumene ne-PMS-TC enye.
Imodeli esebenzayo ye-SHDSL transceiver (STU)
Imodyuli ye-TPS-TC ixhomekeke kwisicelo apho isixhobo sisetyenziswa (i-Ethernet, RS-232/422/485, njl.). Umsebenzi wayo kukuguqula idatha yomsebenzisi kwifomathi ye-SHDSL, yenza i-multiplexing / demultiplexing kunye nokulungiswa kwexesha leendlela ezininzi zedatha yomsebenzisi.
Kwinqanaba le-PMS-TC, iifreyimu ze-SHDSL zenziwe kwaye zilungelelaniswe, kunye nokukrazula kunye nokukrazula.
Imodyuli ye-PMD yenza imisebenzi yolwazi lwe-encoding / decoding, modulation / demodulation, echo cancellation, parameter uthethathethwano kumgca wonxibelelwano kunye nokuseka uxhulumaniso phakathi kwe-transceivers. Kukwinqanaba le-PMD ukuba imisebenzi ephambili yenziwa ukuze kuqinisekiswe ukhuseleko lwengxolo ephezulu ye-SHDSL, kubandakanywa ikhowudi ye-TCPAM (i-Trellis ikhowudi kunye ne-analog pulse modulation), ikhowudi edibeneyo kunye ne-modulation mechanism ephucula ukusebenza kakuhle kwe-spectral yomqondiso xa kuthelekiswa nokwahlukileyo. indlela. Umgaqo wokusebenza wemodyuli ye-PMD unokumelwa ngendlela yomzobo osebenzayo.
PMD kwiModyuli Block Diagram
I-TC-PAM isekwe kusetyenziso lwe-encoder convolutional eyenza ulandelelwano olungafunekiyo lweebits kwicala lothumelo lwe-SHDSL. Kumjikelo wewotshi nganye, isuntswana ngalinye elifikayo kwigalelo le-encoder labelwa i-double bit (dibit) kwimveliso. Ngaloo ndlela, ngexabiso lokungafuneki okuncinci, ukukhuseleka kwengxolo yokudluliselwa kuyanda. Ukusetyenziswa kwe-Trellis modulation kukuvumela ukuba unciphise i-bandwidth yedatha esetyenzisiweyo kwaye wenze lula i-hardware ngelixa ugcina umlinganiselo ofanayo wesignali ukuya kwingxolo.
Umgaqo wokuSebenza we-Trellis encoder (TC-PAM 16)
I-double bit yenziwa yi-logical bit modulo-2 (ekhethekileyo-okanye) esekelwe kwi-bit yegalelo x1(tn) kunye neebits x1(tn-1), x1(tn-2), njl. (kunokubakho ukuya kuthi ga kwi-20 kubo bebonke), ezifunyenwe kwi-encoder input ngaphambili kwaye zahlala zigcinwe kwiirejista zeememori. Kumjikelo wewotshi elandelayo ye-encoder tn+1, amasuntswana azakutshintshelwa kwiiseli zenkumbulo ukwenza umsebenzi onengqondo: bit x1(tn) izakuya kwinkumbulo, ishenxisa lonke ulandelelwano lwamasuntswana agcinwe apho.
Convolutional encoder algorithm
Iitheyibhile zenyaniso zokongeza imodyuli yesi-2
Ukucaca, kulungele ukusebenzisa umzobo welizwe we-encoder ye-convolution, apho unokubona ukuba i-encoder ikuyo imeko ngamanye amaxesha tn, tn+1, njl. kuxhomekeke kwidatha yegalelo. Kulo mzekelo, i-encoder state ithetha iperi yamaxabiso ye-bit yegalelo x1(tn) kunye ne-bit kwimemori yokuqala yeseli x1(tn-1). Ukwakha umzobo, ungasebenzisa igrafu, kwii-vertices apho kukho iimeko ezinokwenzeka ze-encoder, kwaye uguqulo ukusuka kwelinye ilizwe ukuya kwelinye luboniswa ngamasuntswana egalelo ahambelanayo x1(tn) kunye needibhithi zemveliso $inline$y ₀y ₁(t ₀)$inline$.
Idayagram yelizwe kunye negrafu yotshintsho ye-encoder ye-convolution yesidluliseli
Kwi-transmitter, ngokusekelwe kwiibhithi ezine ezifunyenweyo (iinqununu ezimbini zokuphuma kwe-encoder kunye neebhithi ezimbini zedatha), isimboli senziwe, ngasinye sihambelana ne-amplitude yayo yesignali yokumodareyitha ye-analog-pulse modulator.
Imeko ye-16-bit AIM ngokuxhomekeke kwixabiso le-bit-bit character
Kwicala lomamkeli womqondiso, inkqubo ebuyela umva iyenzeka - ukuchithwa kunye nokukhetha kwikhowudi engafunekiyo (i-double bits y0y1 (tn)) yolandelelwano olufunekayo lwe-input bits ye-encoder x1 (tn). Lo msebenzi wenziwa yiViterbi decoder.
I-algorithm yedekhowuda isekwe ekubaleni impazamo yometriki kuzo zonke iimeko ezilindelekileyo zekhowudi yekhowudi. Impazamo yemetric ibhekisa kumahluko phakathi kweebits ezifunyenweyo kunye neebits ezilindelekileyo kwindlela nganye enokwenzeka. Ukuba akukho ziphoso zokufumana, ngoko ke umethrikhi wempazamo yendlela yokwenyani iya kuba ngu-0 kuba akukho mahluko kancinane. Kwiindlela zobuxoki, i-metric iya kwahluka kwi-zero, inyuka rhoqo, kwaye emva kwexesha elithile i-decoder iya kuyeka ukubala indlela ephosakeleyo, ishiya eyona nyani kuphela.
Idayagram yemeko ye-encoder ibalwe yi-Viterbi decoder yomamkeli
Kodwa le algorithm iqinisekisa njani ukungazinzi ingxolo? Ukucinga ukuba umamkeli ufumene idatha ngempazamo, i-decoder iya kuqhubeka nokubala iindlela ezimbini nge-metric yephutha ye-1. Indlela ene-error metric ye-0 ayisayi kubakho. Kodwa i-algorithm iya kwenza isigqibo malunga nokuba yeyiphi indlela eyinyani kamva ngokusekwe kumasuntswana amabini alandelayo afunyenweyo.
Xa kwenzeka iphutha lesibini, kuya kubakho iindlela ezininzi ezine-metric 2, kodwa indlela echanekileyo iya kuchongwa kamva ngokusekelwe kwindlela ephezulu yokunokwenzeka (oko kukuthi, ubuncinci be-metric).
Umzobo we-encoder state ubalwe yi-Viterbi decoder xa ufumana idatha ngeempazamo
Kwimeko echazwe ngasentla, njengomzekelo, siqwalasele i-algorithm yenkqubo ye-16-bit (TC-PAM16), eqinisekisa ukuhanjiswa kweebhithi ezintathu zolwazi oluncedo kunye nencinci eyongezelelweyo yokukhusela impazamo kwisimboli esinye. I-TC-PAM16 ifezekisa amaxabiso edatha ukusuka kwi-192 ukuya kwi-3840 kbps. Ngokwandisa ubunzulu be-bit ukuya kwi-128 (iinkqubo zanamhlanje zisebenza kunye ne-TC-PAM128), amasuntswana amathandathu olwazi oluluncedo ahanjiswa kwisimboli ngasinye, kwaye isantya esiphezulu esifikelelekayo sisuka kwi-5696 kbps ukuya kwi-15,3 Mbps.
Ukusetyenziswa kwe-analog pulse modulation (PAM) yenza i-SHDSL ifane nenani lemigangatho ye-Ethernet eyaziwayo, njenge-gigabit 1000BASE-T (PAM-5), i-10-gigabit 10GBASE-T (PAM-16) okanye i-industrial single-pair Ethernet 2020BASE -T10L, ethembisayo kwi-1 (PAM-3).
SHDSL phezu kothungelwano Ethernet
Kukho iimodem ze-SHDSL ezilawulwayo nezingalawulwayo, kodwa olu lwahlulo luncinci kunye nolwahlulo oluqhelekileyo kwizixhobo ezilawulwayo nezingalawulwayo ezikhoyo, umzekelo, ukutshintshwa kwe-Ethernet. Umahluko ulele kuqwalaselo kunye nezixhobo zokubeka iliso. Iimodem ezilawulwayo ziqwalaselwe nge-interface yewebhu kwaye zinokufunyaniswa nge-SNMP, ngelixa iimodem ezingalawulwayo zinokufunyaniswa zisebenzisa isoftware eyongezelelweyo nge-console port (kwiPhoenix Qhagamshelana le yinkqubo yePSI-CONF yasimahla kunye ne-mini-USB interface). Ngokungafaniyo nokutshintsha, iimodem ezingalawulwayo zinokusebenza kwinethiwekhi ene-ring topology.
Kungenjalo, iimodem ezilawulwayo nezingalawulwayo ziyafana ngokupheleleyo, kuquka ukusebenza kunye nokukwazi ukusebenza kwiPlug&umgaqo wokuDlala, oko kukuthi, ngaphandle koqwalaselo lokuqala.
Ukongeza, iimodem zinokuxhotyiswa ngemisebenzi yokhuselo lokutya kunye nokukwazi ukuyixilonga. Uthungelwano lwe-SHDSL lunokwenza amacandelo amade kakhulu, kwaye abaqhubi banokudlula kwiindawo apho ukunyuka (okubangelwa ukungafani okunokuthi kubangelwa ukukhutshwa kombane okanye iisekethe ezimfutshane kwiintambo zentambo ezikufutshane) zingenzeka. Umbane owenziweyo unokubangela ukuba imisinga yokukhutshwa kweekilomperes ihambe. Ngoko ke, ukukhusela izixhobo kwizinto ezinjalo, ii-SPD zakhiwe kwiimodem ngendlela yebhodi ekhutshwayo, enokutshintshwa xa kuyimfuneko. Kukwibhloko ye-terminal yale bhodi apho umgca we-SHDSL uqhagamshelwe.
Topology
Ukusebenzisa i-SHDSL phezu kwe-Ethernet, kunokwenzeka ukwakha amanethiwekhi kunye nayiphi na i-topology: i-point-to-point, umgca, inkwenkwezi kunye nendandatho. Ngexesha elifanayo, kuxhomekeke kuhlobo lwemodem, ungasebenzisa zombini i-2-wire kunye ne-4-wire network lines for connection.
I-Ethernet topology yenethiwekhi esekelwe kwi-SHDSL
Kwakhona kunokwenzeka ukwakha iinkqubo ezisasazwayo kunye ne-topology edibeneyo. Icandelo ngalinye lenethiwekhi ye-SHDSL ingaba neemodem ezingama-50 kwaye, ngokuqwalasela amandla omzimba wethekhinoloji (umgama phakathi kweemodem yi-20 km), ubude becandelo bunokufikelela kwi-1000 km.
Ukuba imodem elawulwayo ifakwe kwintloko yecandelo ngalinye elinjalo, ngoko ukunyaniseka kwecandelo kunokufunyaniswa kusetyenziswa i-SNMP. Ukongeza, iimodem ezilawulwayo nezingalawulwayo zixhasa itekhnoloji yeVLAN, oko kukuthi, zikuvumela ukuba uhlukanise umnatha kwii-subnets ezinengqiqo. Izixhobo nazo ziyakwazi ukusebenza kunye neeprotocol zokudlulisa idatha ezisetyenziswa kwiinkqubo ezizenzekelayo zanamhlanje (i-Profinet, i-Ethernet / IP, i-Modbus TCP, njl.).
Ugcino lwamajelo onxibelelwano kusetyenziswa i-SHDSL
I-SHDSL isetyenziselwa ukwenza iziteshi zonxibelelwano ezingafunekiyo kwinethiwekhi ye-Ethernet, ehlala ibonwa ngamehlo.
I-SHDSL kunye ne-serial interface
Iimodem ze-SHDSL ezinojongano lwe-serial ukoyisa imida kumgama, i-topology kunye nomgangatho womqhubi okhoyo kwiinkqubo zeentambo zemveli ezisekelwe kwii-transceivers ezi-asynchronous (UART): RS-232 - 15 m, RS-422 kunye ne-RS-485 - 1200 m.
Kukho iimodem ezine-serial interfaces (RS-232/422/485) kuzo zombini izicelo ze-universal kunye nezizodwa (umzekelo, kwiProfibus). Zonke ezo zixhobo ziyinxalenye “engalawulwayo”, ngenxa yoko ziqwalaselwe kwaye zifunyaniswe kusetyenziswa isoftware ekhethekileyo.
Topology
Kwiinethiwekhi ezine-interface ye-serial, usebenzisa i-SHDSL kunokwenzeka ukwakha amanethiwekhi kunye ne-point-to-point, i-line kunye neenkwenkwezi zeenkwenkwezi. Ngaphakathi kwe-topology yomgca, kunokwenzeka ukudibanisa ukuya kwii-nodes ze-255 kwinethiwekhi enye (kwi-Profibus - 30).
Kwiinkqubo ezakhiwe kusetyenziswa kuphela izixhobo ze-RS-485, akukho zithintelo kwiprotocol yokudlulisa idatha esetyenzisiweyo, kodwa i-topology yomgca kunye neenkwenkwezi ziyi-atypical ye-RS-232 kunye ne-RS-422, ngoko ke ukusebenza kwezixhobo zokugqibela kwinethiwekhi ye-SHDSL kunye ne-topology efanayo. inokwenzeka kuphela kwimowudi yesiqingatha se-duplex. Kwangaxeshanye, kwiinkqubo ezine-RS-232 kunye ne-RS-422, idilesi yesixhobo kufuneka inikezelwe kwinqanaba leprotocol, elingaqhelekanga kwi-interfaces edla ngokusetyenziswa kwiinethiwekhi ze-point-to-point.
Xa udibanisa izixhobo kunye neentlobo ezahlukeneyo ze-interfaces nge-SHDSL, kuyimfuneko ukuthathela ingqalelo into yokuba akukho ndlela enye yokuseka uxhulumaniso (ukuxhawula ngesandla) phakathi kwezixhobo. Nangona kunjalo, kusenokwenzeka ukuba uququzelele utshintshiselwano kule meko, le miqathango ilandelayo kufuneka ifezekiswe:
- ukulungelelaniswa konxibelelwano kunye nolawulo lokudluliselwa kwedatha kufuneka lwenziwe kwinqanaba leprotocol yokudlulisa ulwazi oludibeneyo;
- zonke izixhobo zokuphela kufuneka zisebenze kwimowudi enesiqingatha-ephindwe kabini, ekufuneka kwakhona zixhaswe yiprotocol yolwazi.
Iprotocol ye-Modbus RTU, iprotocol eqhelekileyo ye-interfaces ye-asynchronous, ikuvumela ukuba ugweme yonke imida echazwe kwaye wakhe inkqubo enye eneentlobo ezahlukeneyo zojongano.
Uthotho lwetoplogi zenethiwekhi esekwe kwi-SHDSL
Xa usebenzisa i-RS-485 yocingo ezimbini kwizixhobo Unokwakha izakhiwo ezinzima ngakumbi ngokudibanisa iimodem ngebhasi enye kuloliwe weDIN. Ukunikezelwa kwamandla kunokufakwa kwibhasi enye (kule meko, zonke izixhobo zinikwe amandla ngebhasi) kunye nabaguquli be-optical bochungechunge lwe-PSI-MOS ukudala inethiwekhi edibeneyo. Imeko ebalulekileyo yokusebenza kwenkqubo enjalo isantya esifanayo sazo zonke ii-transceivers.
Iimpawu ezongezelelweyo ze-SHDSL kwinethiwekhi ye-RS-485
Imizekelo yesicelo
Itekhnoloji ye-SHDSL isetyenziswa ngokusebenzayo kwizinto eziluncedo zikamasipala eJamani. Iinkampani ezingaphezu kwama-50 ezibonelela ngeenkqubo eziluncedo zesixeko zisebenzisa iingcingo zobhedu ezindala ukudibanisa izinto ezisasazwa kuso sonke isixeko ngothungelwano olunye. Okokuqala, iinkqubo zolawulo nokubalwa kwamanzi, igesi kunye nonikezelo lwamandla zakhiwe kwi-SHDSL. Phakathi kwezi zixeko kukho iUlm, iMagdeburg, i-Ingolstadt, iBielefeld, iFrankfurt an der Oder nezinye ezininzi.
Eyona nkqubo inkulu esekwe kwi-SHDSL yenziwa kwisixeko saseLübeck. Inkqubo inesakhiwo esidibeneyo esekelwe kwi-Ethernet ye-optical kunye ne-SHDSL, idibanisa izinto ze-120 ezikude ukusuka komnye nomnye kwaye isebenzisa iimodem ezingaphezu kwe-50. . Inethiwekhi iphela ifunyaniswa kusetyenziswa i-SNMP. Elona candelo lide ukusuka eKalkhorst ukuya kwisikhululo seenqwelomoya iLübeck ziikhilomitha ezingama-39 ubude. Isizathu sokuba inkampani yomxhasi ikhethe i-SHDSL kukuba yayingekho ngokwezoqoqosho ukuphumeza iprojekthi ngokupheleleyo kwi-optics, ngenxa yokufumaneka kweentambo zobhedu ezindala.
Ukuhanjiswa kwedatha ngeringi yokutyibilika
Umzekelo onomdla kugqithiso lwedatha phakathi kwezinto ezihambayo, ezifana nokwenziwa kwiiinjini zomoya okanye koomatshini abakhulu bokujija bamashishini. Inkqubo efanayo isetyenziselwa ukutshintshiselana ngolwazi phakathi kwabalawuli ababekwe kwi-rotor kunye ne-stator yezityalo. Kule meko, umnxibelelwano we-sliding ngendandatho ye-slip isetyenziselwa ukuhambisa idatha. Imizekelo efana nale ibonisa ukuba akuyimfuneko ukuba noqhagamshelwano olusisigxina ukuhambisa idatha kwi-SHDSL.
Ukuthelekisa nezinye itekhnoloji
SHDSL vs GSM
Ukuba sithelekisa i-SHDSL kunye neenkqubo zokuhanjiswa kwedatha ngokusekelwe kwi-GSM (3G / 4G), ngoko ukungabikho kweendleko zokusebenza ezinxulumene neentlawulo eziqhelekileyo kumqhubi wokufikelela kwinethiwekhi yeselula kuthetha ngokuthanda i-DSL. Nge-SHDSL, sizimele kwindawo yokugubungela, umgangatho kunye nokuthembeka konxibelelwano lweselula kwiziko loshishino, kubandakanywa ukuchasana nokuphazamiseka kwe-electromagnetic. Nge-SHDSL akukho mfuneko yokuqwalasela izixhobo, ezikhawuleza ukugunyaziswa kweziko. Iinethiwekhi ezingenazintambo zibonakaliswe ngokulibaziseka okukhulu ekuhanjisweni kwedatha kunye nobunzima bokudlulisa idatha usebenzisa i-multicast traffic (i-Profinet, i-Ethernet IP).
Ukhuseleko lolwazi luthetha ngokuthanda i-SHDSL ngenxa yokungabikho kwesidingo sokudlulisa idatha kwi-Intanethi kunye nesidingo sokuqwalasela uxhulumaniso lwe-VPN kule nto.
SHDSL vs Wi-Fi
Uninzi lwezinto ezithethiweyo nge-GSM zinokusetyenziswa kwi-Wi-Fi yeshishini. Ukungakhuseleki kwengxolo ephantsi, umgama ongephi wokuhanjiswa kwedatha, ukuxhomekeka kwi-topology yendawo, kunye nokulibaziseka kokuhanjiswa kwedatha kuthetha ngokuchasene ne-Wi-Fi. Eyona nto ibalulekileyo i-drawback lukhuseleko lolwazi lweenethiwekhi ze-Wi-Fi, kuba nabani na unokufikelela kwindawo yokudlulisa idatha. Nge-Wi-Fi sele ikwazi ukuthumela iProfinet okanye i-Ethernet IP data, eya kuba nzima nge-GSM.
SHDSL vs optics
Kwiimeko ezininzi, i-optics inenzuzo enkulu ngaphezu kwe-SHDSL, kodwa kwinani lezicelo ze-SHDSL ikuvumela ukuba ulondoloze ixesha kunye nemali ekubekeni nasekudibaniseni iintambo ze-optical, ukunciphisa ixesha elithathayo ukubeka indawo yokusebenza. I-SHDSL ayifuni iziqhagamshelo ezikhethekileyo, kuba intambo yonxibelelwano ixhunywe kwi-terminal yemodem. Ngenxa yeempawu zemishini yeentambo ze-optical, ukusetyenziswa kwazo kulinganiselwe kwizicelo ezibandakanya ukuhanjiswa kolwazi phakathi kwezinto ezihambayo, apho abaqhubi bezobhedu baxhaphake kakhulu.
umthombo: www.habr.com
