Duk da yawaitar amfani da hanyoyin sadarwa na Ethernet, fasahar sadarwa ta tushen DSL sun kasance masu dacewa har yau. Har zuwa yanzu, ana iya samun DSL a cikin hanyoyin sadarwar mil na ƙarshe don haɗa kayan aikin masu biyan kuɗi zuwa cibiyoyin sadarwar masu ba da Intanet, kuma kwanan nan ana ƙara yin amfani da fasahar wajen gina hanyoyin sadarwa na gida, alal misali, a aikace-aikacen masana'antu, inda DSL ke aiki azaman mai dacewa da Ethernet. ko hanyoyin sadarwar filin da aka dogara akan RS-232/422/485. Irin waɗannan hanyoyin samar da masana'antu ana amfani da su sosai a cikin ƙasashen Turai da Asiya da suka ci gaba.
DSL iyali ne na ma'auni waɗanda aka samo asali don watsa bayanan dijital ta hanyar layin tarho. A tarihi, ya zama fasahar samun damar Intanet ta hanyar sadarwa ta farko, ta maye gurbin DIAL UP da ISDN. Bambance-bambancen ma'auni na DSL da ke wanzuwa a halin yanzu shine saboda gaskiyar cewa kamfanoni da yawa, waɗanda suka fara a cikin 80s, sun yi ƙoƙarin haɓakawa da tallata fasahar nasu.
Duk waɗannan ci gaba za a iya raba su zuwa manyan nau'i biyu - fasahar asymmetric (ADSL) da fasaha (SDSL). Asymmetric yana nufin waɗanda saurin haɗin mai shigowa ya bambanta da saurin zirga-zirga. Ta hanyar simmetric muna nufin cewa saurin liyafar da watsawa daidai suke.
Shahararrun ma'auni na asymmetric da aka fi sani da yaduwa sune, a zahiri, ADSL (a cikin sabuwar bugu - ADSL2+) da VDSL (VDSL2), daidaitacce - HDSL (bayanin martaba) da SHDSL. Dukkansu sun bambanta da juna ta yadda suke aiki a mitoci daban-daban kuma suna amfani da hanyoyi daban-daban na coding da daidaitawa akan layin sadarwa ta zahiri. Hanyoyin gyaran kuskure kuma sun bambanta, yana haifar da matakan rigakafi daban-daban. Sakamakon haka, kowace fasaha tana da nata iyaka a cikin sauri da nisa na watsa bayanai, gami da ya danganta da nau'i da ingancin na'urar.
Iyaka na ma'auni na DSL daban-daban
A cikin kowace fasaha ta DSL, adadin canja wurin bayanai yana raguwa yayin da tsayin kebul ya karu. A matsananciyar nisa yana yiwuwa a sami saurin kilobits ɗari da yawa, amma lokacin watsa bayanai sama da 200-300 m, matsakaicin yuwuwar saurin yana samuwa.
Daga cikin dukkanin fasahohin, SHDSL yana da amfani mai mahimmanci wanda ya sa ya yiwu a yi amfani da shi a cikin aikace-aikacen masana'antu - haɓakar amo da kuma ikon yin amfani da kowane nau'i na madubi don watsa bayanai. Ba haka lamarin yake ba tare da ma'aunin asymmetric, kuma ingancin sadarwa ya dogara sosai kan ingancin layin da ake amfani da shi don watsa bayanai. Musamman, ana ba da shawarar yin amfani da kebul na tarho mai murɗi. A wannan yanayin, mafita mafi aminci shine amfani da kebul na gani maimakon ADSL da VDSL.
Duk wani nau'i na masu gudanarwa da aka ware daga juna ya dace da SHDSL - jan karfe, aluminum, karfe, da dai sauransu. Matsakaicin watsawa na iya zama tsohuwar wayoyi na lantarki, tsoffin layin tarho, shingen shinge, da dai sauransu.
Dogaro da saurin watsa bayanai na SHDSL akan nisa da nau'in jagora
Daga jadawali na saurin canja wurin bayanai tare da nisa da nau'in madugu da aka bayar don SHDSL, zaku iya ganin cewa masu gudanarwa tare da babban ɓangaren giciye suna ba ku damar watsa bayanai akan nisa mafi girma. Godiya ga fasaha, yana yiwuwa a tsara sadarwa a kan nisa har zuwa kilomita 20 a matsakaicin yiwuwar saurin 15.3 Mb/s don kebul na waya 2 ko 30 Mb don kebul na 4-waya. A cikin aikace-aikace na gaske, ana iya saita saurin watsawa da hannu, wanda ya zama dole a cikin yanayi na tsangwama mai ƙarfi na lantarki ko ƙarancin ingancin layi. A wannan yanayin, don haɓaka nisan watsawa, ya zama dole don rage saurin na'urorin SHDSL. Don lissafin saurin daidai gwargwadon nisa da nau'in jagora, zaku iya amfani da software kyauta kamar .
Me yasa SHDSL ke da babban rigakafin amo?
Ƙa'idar aiki na SHDSL transceiver za a iya wakilta a cikin nau'i na zane-zane, wanda aka bambanta wani ɓangare na musamman da mai zaman kanta (m) daga ra'ayi na aikace-aikacen. Bangaren mai zaman kansa ya ƙunshi PMD (Matsakaicin Matsakaici na Jiki) da PMS-TC (Matsakaici-Takamaiman TC Layer) tubalan ayyuka, yayin da takamaiman ɓangaren ya haɗa da TPS-TC (Transmission Protocol-Specific TC Layer) Layer da bayanan mai amfani.
Hanya ta zahiri tsakanin transceivers (STUs) na iya kasancewa azaman nau'i-nau'i ɗaya ko igiyoyi guda biyu masu yawa. A cikin yanayin nau'i-nau'i na USB da yawa, STU ya ƙunshi PMDs masu zaman kansu da yawa masu alaƙa da PMS-TC guda ɗaya.
Samfurin aiki na SHDSL transceiver (STU)
Tsarin TPS-TC ya dogara da aikace-aikacen da ake amfani da na'urar (Ethernet, RS-232/422/485, da sauransu). Ayyukansa shine canza bayanan mai amfani zuwa tsarin SHDSL, yin multixing / demultiplexing da daidaita lokaci na tashoshi da yawa na bayanan mai amfani.
A matakin PMS-TC, an ƙirƙiri firam ɗin SHDSL kuma an daidaita su, haka kuma ana zage-zage da ɓarna.
Tsarin PMD yana aiwatar da ayyukan ɓoyayyiyar bayanai/bayani, daidaitawa/demodulation, sokewar echo, shawarwarin siga akan layin sadarwa da kafa haɗin kai tsakanin transceivers. A matakin PMD ne ake aiwatar da manyan ayyuka don tabbatar da babban amo na rigakafi na SHDSL, gami da lambar TCPAM (Trellis coding tare da tsarin bugun jini na analog), tsarin haɗin gwiwa da tsarin daidaitawa wanda ke haɓaka ingantaccen siginar siginar idan aka kwatanta da daban. hanya. Hakanan ana iya wakilta ƙa'idar aiki na ƙirar PMD a cikin sigar zane mai aiki.
PMD Module Block zane
TC-PAM ya dogara ne akan amfani da na'urar rikodin juyin juya hali wanda ke haifar da jerin raƙuman raƙuman ruwa a gefen mai watsa SHDSL. A kowane zagayowar agogo, kowane bit da ya isa wurin shigar da maɓalli ana sanya shi sau biyu (dibit) a wurin fitarwa. Don haka, a farashin ɗan ƙaranci kaɗan, rigakafin amo yana ƙaruwa. Yin amfani da ƙirar Trellis yana ba ku damar rage bandwidth watsa bayanai da aka yi amfani da su da sauƙaƙe kayan aikin yayin kiyaye siginar sigina iri ɗaya.
Ƙa'idar aiki na Trellis encoder (TC-PAM 16)
Biyu bit yana samuwa ta hanyar aiki mai ma'ana na modulo-2 (keɓaɓɓe-ko) ƙari dangane da shigar da bit x1(tn) da bits x1(tn-1), x1(tn-2), da sauransu. (ana iya samun har zuwa 20 daga cikinsu gabaɗaya), waɗanda aka karɓa a shigar da rikodin kafin kuma sun kasance a adana su a cikin rajistar ƙwaƙwalwar ajiya. A zagaye na gaba na encoder tn+1, za a canza rago a cikin sel memori don aiwatar da aiki mai ma'ana: bit x1(tn) zai matsa zuwa ƙwaƙwalwar ajiya, yana canza duk jerin raƙuman da aka adana a wurin.
Convolutional algorithm
Tables na gaskiya don ƙarin aiki modulo 2
Don fayyace, ya dace a yi amfani da ginshiƙi na jaha na mahaɗar juzu'i, daga inda za ku iya ganin irin yanayin da encoder ɗin yake a wasu lokuta tn, tn+1, da sauransu. dangane da shigar bayanan. A wannan yanayin, yanayin ɓoye yana nufin nau'i biyu na ƙimar shigarwar bit x1(tn) da bit a cikin tantanin ƙwaƙwalwa na farko x1(tn-1). Don gina zane, za ku iya amfani da jadawali, a gefensa akwai yuwuwar jihohi na encoder, kuma sauye-sauye daga wannan jiha zuwa waccan ana nuna su ta hanyar shigar da madaidaicin bits x1(tn) da fitarwa dibit $inline$y ₀y ₁(t₀)$inline$.
Zane-zane na jiha da jadawali na canji na mai rikodi mai juyi
A cikin mai watsawa, dangane da rago huɗu da aka karɓa (fitowa guda biyu na encoder da bits data biyu), an ƙirƙiri wata alama, wacce kowannensu yayi daidai da girmansa na siginar daidaitawa na injin bugun bugun jini.
Yanayin 16-bit AIM ya danganta da ƙimar halayen-bit huɗu
A gefen mai karɓar siginar, tsarin jujjuyawar yana faruwa - ƙaddamarwa da zaɓi daga lambar da ba ta da yawa (biyu-biyu y0y1(tn)) na jerin abubuwan da ake buƙata na raƙuman shigarwa na encoder x1(tn). Ana yin wannan aikin ta hanyar na'urar tantancewa ta Viterbi.
Algorithm na decoder ya dogara ne akan ƙididdige ma'auni na kuskure don duk yuwuwar jihohin ɓoyayyen da ake sa ran. Ma'aunin kuskure yana nufin bambanci tsakanin ragowar da aka karɓa da raƙuman raƙuman da ake sa ran ga kowace hanya mai yiwuwa. Idan babu kurakurai masu karɓa, to ma'aunin kuskuren hanya na gaskiya zai zama 0 saboda babu ɗan bambanci. Don hanyoyin ƙarya, ma'aunin zai bambanta da sifili, yana ƙaruwa koyaushe, kuma bayan ɗan lokaci mai ƙididdigewa zai daina ƙididdige hanyar da ba daidai ba, yana barin gaskiya kawai.
Zane-zane na jihar Encoder wanda aka ƙididdige shi ta hanyar mai ƙididdigewa na Viterbi mai karɓa
Amma ta yaya wannan algorithm ke tabbatar da rigakafin amo? Da ɗauka cewa mai karɓa ya karɓi bayanan a cikin kuskure, mai ƙididdigewa zai ci gaba da ƙididdige hanyoyi biyu tare da ma'aunin kuskure na 1. Hanyar da ke da ma'aunin kuskure na 0 ba za ta wanzu ba. Amma algorithm din zai yanke hukunci game da wace hanya ce gaskiya daga baya dangane da rago biyu na gaba da aka karɓa.
Lokacin da kuskure na biyu ya faru, za a sami hanyoyi da yawa tare da ma'auni 2, amma za a gano madaidaicin hanya daga baya bisa mafi girman hanyar da za a iya (watau mafi ƙarancin awo).
Zane-zane na jihar Encoder wanda Viterbi decoder ya ƙidaya lokacin karɓar bayanai tare da kurakurai
A cikin yanayin da aka bayyana a sama, a matsayin misali, mun yi la'akari da algorithm na tsarin 16-bit (TC-PAM16), wanda ke tabbatar da watsa bayanai na rago uku na bayanai masu amfani da ƙarin bit don kare kuskure a cikin alama ɗaya. TC-PAM16 yana samun ƙimar bayanai daga 192 zuwa 3840 kbps. Ta hanyar haɓaka zurfin bit zuwa 128 (tsarin zamani yana aiki tare da TC-PAM128), ana watsa ragowa shida na bayanai masu amfani a kowace alama, kuma matsakaicin matsakaicin saurin da za a iya samu daga 5696 kbps zuwa 15,3 Mbps.
Yin amfani da na'urar bugun jini na analog (PAM) yana sa SHDSL yayi kama da adadin shahararrun ka'idodin Ethernet, kamar gigabit 1000BASE-T (PAM-5), 10-gigabit 10GBASE-T (PAM-16) ko masana'antu guda-biyu Ethernet 2020BASE -T10L, wanda ke da alƙawarin 1 (PAM-3).
SHDSL akan hanyoyin sadarwar Ethernet
Akwai modem SHDSL da ba a sarrafa ba, amma wannan rarrabuwar ba ta da alaƙa da rarrabuwar da aka saba zuwa na'urori masu sarrafawa da waɗanda ba a sarrafa su waɗanda ke wanzu, alal misali, don masu sauya Ethernet. Bambanci ya ta'allaka ne a cikin tsari da kayan aikin sa ido. Ana saita modems ɗin sarrafawa ta hanyar haɗin yanar gizo kuma ana iya gano su ta SNMP, yayin da modem ɗin da ba a sarrafa ba za'a iya bincikar su ta amfani da ƙarin software ta hanyar tashar wasan bidiyo (don Phoenix Contact wannan shirin PSI-CONF ne kyauta da karamin kebul na USB). Ba kamar masu sauyawa ba, modem ɗin da ba a sarrafa su na iya aiki a cikin hanyar sadarwa tare da topology na zobe.
In ba haka ba, modem ɗin sarrafawa da mara sarrafa iri ɗaya ne, gami da aiki da ikon yin aiki akan ƙa'idar Plug&Play, wato, ba tare da wani tsari na farko ba.
Bugu da ƙari, ana iya sanye take da modem tare da ayyukan kariya mai ƙarfi tare da ikon tantance su. Cibiyoyin sadarwar SHDSL na iya samar da sassa masu tsayi sosai, kuma masu gudanarwa na iya gudana a wuraren da ƙarfin lantarki (sakamakon yuwuwar bambance-bambancen da ke haifar da fitar walƙiya ko gajerun da'irori a cikin layin kebul na kusa) na iya faruwa. Wutar lantarki da aka jawo na iya haifar da kwararar igiyoyin kiloamperes. Sabili da haka, don kare kayan aiki daga irin waɗannan abubuwan, an gina SPDs a cikin modem a cikin nau'i na allon cirewa, wanda za'a iya maye gurbin idan ya cancanta. Yana da tashar tashar tashar wannan jirgi aka haɗa layin SHDSL.
Topologies
Yin amfani da SHDSL akan Ethernet, yana yiwuwa a gina cibiyoyin sadarwa tare da kowane topology: aya-zuwa-aya, layi, tauraro da zobe. A lokaci guda, dangane da nau'in modem, zaka iya amfani da duka biyu-waya da 2-waya layukan sadarwa don haɗi.
Ethernet topologies cibiyar sadarwa bisa SHDSL
Hakanan yana yiwuwa a gina tsarin da aka rarraba tare da haɗuwa da topology. Kowane yanki na cibiyar sadarwa na SHDSL na iya samun har zuwa 50 modem kuma, la'akari da damar jiki na fasaha (nisa tsakanin modems shine 20 km), tsayin sashi zai iya kaiwa kilomita 1000.
Idan an shigar da modem mai sarrafawa a kan kowane irin wannan sashin, to ana iya gano amincin sashin ta amfani da SNMP. Bugu da kari, modem masu sarrafawa da marasa sarrafawa suna tallafawa fasahar VLAN, wato, suna ba ku damar raba hanyar sadarwa zuwa madaidaitan subnets. Hakanan na'urorin suna da ikon yin aiki tare da ka'idojin canja wurin bayanai da ake amfani da su a cikin tsarin sarrafa kansa na zamani (Profinet, Ethernet/IP, Modbus TCP, da sauransu).
Ajiye tashoshin sadarwa ta amfani da SHDSL
Ana amfani da SHDSL don ƙirƙirar tashoshi na sadarwa da yawa a cikin hanyar sadarwar Ethernet, galibi na gani.
SHDSL da serial interface
SHDSL modems tare da serial dubawa sun shawo kan iyakancewa a nesa, topology da ingancin madugu waɗanda ke wanzu don tsarin waya na gargajiya dangane da transceivers asynchronous (UART): RS-232 - 15 m, RS-422 da RS-485 - 1200 m.
Akwai modem masu mu'amala da siriyal (RS-232/422/485) don aikace-aikacen duniya duka da na musamman (misali, na Profibus). Duk irin waɗannan na'urori suna cikin nau'in "marasa sarrafawa", saboda haka ana saita su kuma an gano su ta amfani da software na musamman.
Topologies
A cikin cibiyoyin sadarwa tare da kewayon kewayon, ta amfani da SHDSL yana yiwuwa a gina cibiyoyin sadarwa tare da ma'ana-zuwa-ma'ana, layi da topologies tauraro. A cikin topology na layi, yana yiwuwa a haɗa har zuwa 255 nodes a cikin hanyar sadarwa ɗaya (don Profibus - 30).
A cikin tsarin da aka gina ta amfani da na'urorin RS-485 kawai, babu ƙuntatawa akan ka'idar canja wurin bayanai da aka yi amfani da su, amma layi da topologies na taurari suna da mahimmanci ga RS-232 da RS-422, don haka aikin na'urori na ƙarshe akan hanyar sadarwa ta SHDSL tare da topologies iri ɗaya. mai yiwuwa ne kawai a cikin yanayin rabin-duplex. A lokaci guda, a cikin tsarin tare da RS-232 da RS-422, dole ne a samar da adireshin na'urar a matakin yarjejeniya, wanda ba shi da kyau ga musaya da aka fi amfani da shi a cikin cibiyoyin sadarwa na batu-zuwa.
Lokacin haɗa na'urori tare da nau'ikan musaya daban-daban ta hanyar SHDSL, ya zama dole a la'akari da gaskiyar cewa babu wata hanya ɗaya don kafa haɗin gwiwa (musafaha) tsakanin na'urori. Duk da haka, har yanzu yana yiwuwa a tsara musayar a cikin wannan yanayin; don wannan, dole ne a cika waɗannan sharuɗɗan:
- dole ne a aiwatar da haɗin kai na sadarwa da sarrafa canja wurin bayanai a matakin ƙaƙƙarfan ƙa'idar canja wurin bayanai;
- dole ne duk na'urorin ƙarshe su yi aiki a cikin yanayin rabin duplex, wanda kuma dole ne a goyan bayan ƙa'idar bayani.
Ka'idar Modbus RTU, ƙa'idodin gama gari don mu'amalar asynchronous, yana ba ku damar guje wa duk iyakokin da aka kwatanta da gina tsarin guda ɗaya tare da nau'ikan musaya daban-daban.
Serial topologies cibiyar sadarwa bisa SHDSL
Lokacin amfani da RS-485 mai waya biyu akan kayan aiki Kuna iya gina ƙarin hadaddun sifofi ta hanyar haɗa modem ta cikin bas ɗaya akan dogo na DIN. Ana iya shigar da wutar lantarki a kan bas guda (a wannan yanayin, duk na'urori ana yin amfani da su ta hanyar bas) da masu canza yanayin tsarin PSI-MOS don ƙirƙirar hanyar sadarwa mai haɗuwa. Wani muhimmin yanayin aiki na irin wannan tsarin shine saurin gudu na duk masu wucewa.
Ƙarin fasalulluka na SHDSL akan hanyar sadarwar RS-485
Misalai na aikace-aikace
Ana amfani da fasahar SHDSL sosai a cikin abubuwan amfani na birni a Jamus. Fiye da kamfanoni 50 da ke aiki da tsarin ayyukan birni suna amfani da tsoffin wayoyi na tagulla don haɗa abubuwan da aka rarraba a cikin birni tare da hanyar sadarwa guda ɗaya. Tsarin sarrafawa da lissafin kuɗi don samar da ruwa, gas da makamashi an gina su da farko akan SHDSL. Daga cikin irin wadannan garuruwa akwai Ulm, Magdeburg, Ingolstadt, Bielefeld, Frankfurt an der Oder da dai sauransu.
An kirkiro tsarin tushen SHDSL mafi girma a cikin birnin Lübeck. Tsarin yana da tsarin haɗin gwiwa dangane da Ethernet na gani da SHDSL, yana haɗa abubuwa 120 nesa da juna kuma yana amfani da modem sama da 50. . Ana bincikar duk hanyar sadarwa ta amfani da SNMP. Yankin mafi tsayi daga Kalkhorst zuwa filin jirgin sama na Lübeck yana da tsawon kilomita 39. Dalilin da ya sa kamfanin abokin ciniki ya zaɓi SHDSL shi ne cewa ba a iya yin amfani da tattalin arziki don aiwatar da aikin gaba ɗaya a kan na'urorin gani ba, saboda kasancewar tsofaffin igiyoyi na tagulla.
watsa bayanai ta hanyar zoben zamewa
Misali mai ban sha'awa shine canja wurin bayanai tsakanin abubuwa masu motsi, kamar yadda ake yi a cikin injin turbin iska ko manyan injin karkatar da masana'antu. Ana amfani da irin wannan tsarin don musayar bayanai tsakanin masu sarrafawa da ke kan rotor da stator na shuke-shuke. A wannan yanayin, ana amfani da lambar zamewa ta zoben zamewa don watsa bayanai. Misalai irin wannan suna nuna cewa ba lallai ba ne a sami madaidaicin lamba don watsa bayanai akan SHDSL.
Kwatanta da sauran fasahohin
SHDSL vs GSM
Idan muka kwatanta SHDSL tare da tsarin watsa bayanai dangane da GSM (3G/4G), to, rashin farashin aiki da ke hade da biyan kuɗi na yau da kullum ga mai aiki don samun dama ga hanyar sadarwar wayar hannu yana magana da goyon bayan DSL. Tare da SHDSL, mu masu zaman kansu ne daga wurin ɗaukar hoto, inganci da amincin sadarwar wayar hannu a masana'antar masana'antu, gami da juriya ga tsangwama na lantarki. Tare da SHDSL babu buƙatar saita kayan aiki, wanda ke hanzarta ƙaddamar da kayan aiki. Cibiyoyin sadarwar mara waya suna da alaƙa da babban jinkiri a watsa bayanai da wahala wajen watsa bayanai ta amfani da zirga-zirgar multicast (Profinet, Ethernet IP).
Tsaro na bayanai yana magana da goyon bayan SHDSL saboda rashin buƙatar canja wurin bayanai akan Intanet da buƙatar saita haɗin VPN don wannan.
SHDSL vs Wi-Fi
Yawancin abin da aka faɗi don GSM kuma ana iya amfani da su zuwa Wi-Fi na masana'antu. Karancin rigakafin amo, iyakance tazarar watsa bayanai, dogaro kan yanayin yanki, da jinkirin watsa bayanai suna magana akan Wi-Fi. Babban koma baya shine tsaron bayanan cibiyoyin sadarwar Wi-Fi, saboda kowa yana da damar yin amfani da hanyar watsa bayanai. Tare da Wi-Fi ya riga ya yiwu a watsa bayanan Profinet ko Ethernet IP, wanda zai yi wahala ga GSM.
SHDSL vs Optics
A mafi yawancin lokuta, na'urar gani yana da babban fa'ida akan SHDSL, amma a cikin aikace-aikacen da yawa SHDSL yana ba ku damar adana lokaci da kuɗi akan shimfidawa da walda igiyoyin gani, rage lokacin da ake ɗauka don sanya kayan aiki cikin aiki. SHDSL baya buƙatar masu haɗawa na musamman, saboda ana haɗa kebul na sadarwa kawai zuwa tashar modem. Saboda kayan aikin injiniya na igiyoyi na gani, amfani da su yana iyakance a aikace-aikacen da suka shafi canja wurin bayanai tsakanin abubuwa masu motsi, inda masu sarrafa tagulla suka fi yawa.
source: www.habr.com