Traditional telefoni network ndi mawu ndi dera kusinthana, chofunika kufala burodibandi ya 64kbit/s. Otchedwa VoIP ndi IP paketi kuwombola maukonde monga kufala nsanja, yoyerekeza mawu chizindikiro psinjika, ma CD ndi mndandanda wa processing wapadera, kotero kuti angagwiritse ntchito unconnected UDP protocol kufala.
Zinthu zingapo ndi ntchito zimafunikira kuti mutumize ma siginecha amawu pa netiweki ya IP. Njira yosavuta kwambiri ya netiweki imakhala ndi zida ziwiri kapena zingapo zokhala ndi luso la VoIP zomwe zimalumikizidwa kudzera pa netiweki ya IP.
1.Kusintha kwa Mawu-Data
Chizindikiro cha mawu ndi mawonekedwe a analogi, kudzera pa IP kufalitsa mawu, ngakhale bizinesi yeniyeni yogwiritsira ntchito nthawi yeniyeni kapena bizinesi yogwiritsira ntchito nthawi yeniyeni, choyamba kutembenuka kwa data ya analogi, yomwe ndi chizindikiro cha mawu a analogi 8 kapena 6 quantification, kenako imatumizidwa kumalo osungirako zinthu. , kukula kwa buffer kumatha kusankhidwa malinga ndi zofunikira za kuchedwa ndi kukopera. Ma encoder ambiri otsika amasungidwa mumafelemu.
Kutalika kwa chimango kumayambira 10 mpaka 30 ms. Poganizira za mtengo wotumizira, mapaketi azilankhulo nthawi zambiri amakhala ndi 60, 120, kapena 240ms ya data yolankhula. Kuyika pa digito kutha kukhazikitsidwa pogwiritsa ntchito njira zosiyanasiyana zolembera mawu, ndipo milingo yamakono yamawu ndi ITU-T G.711. Makina ojambulira mawu a komwe akupita ayenera kugwiritsa ntchito algorithm yofananayo kuti chida cholankhulira komwe mukupita chibwezeretsenso chizindikiro cha mawu a analogi.
2.Original data-to-IP kutembenuka
Chizindikiro cholankhulidwa chikasungidwa pa digito, chotsatira ndikusindikiza encode paketi yolankhulira ndi kutalika kwake kwa chimango. Ma encoder ambiri amakhala ndi kutalika kwake kwa chimango. Ngati encoder imagwiritsa ntchito mafelemu a 15ms, phukusi la 60ms kuchokera pamalo oyamba limagawidwa m'mafelemu anayi ndikusindikizidwa motsatizana. Chimango chilichonse chimakhala ndi zitsanzo zolankhula 120 (chitsanzo cha 8kHz). Pambuyo pa encoding, mafelemu anayi othinikizidwawo adapangidwa kukhala phukusi lamawu ophatikizika ndikutumizidwa ku purosesa ya netiweki. Purosesa ya netiweki imawonjezera Baotou, sikelo ya nthawi, ndi zidziwitso zina kumawu ndikuzipereka kumalo ena omaliza kudzera pa netiweki.
Maukonde olankhula amangokhazikitsa kulumikizana kwakuthupi pakati pa ma endpoints (mzere umodzi) ndikutumiza ma encoded sign pakati pa ma endpoints. Mosiyana ndi ma network switching network, maukonde a IP sapanga kulumikizana. Pamafunika kuti zidziwitso ziziyikidwa m'malipoti kapena mapaketi a data ataliatali, kenaka adilesi ndi kuwongolera zambiri pa datagram iliyonse ndikutumizidwa pa netiweki, kutumizidwa komwe mukupita.
3.Kusamutsa
Munjira iyi, netiweki yonse imawonedwa ngati paketi ya mawu yolandilidwa kuchokera pazolowetsayo kenako imatumizidwa ku netiweki yotulutsa mkati mwa nthawi inayake (t). The t akhoza kusiyanasiyana mu osiyanasiyana, kusonyeza jitter mu kufala kwa netiweki.
Node yomweyi pamanetiweki imayang'ana chidziwitso cha maadiresi chomwe chikugwirizana ndi data iliyonse ya IP ndikugwiritsa ntchito chidziwitsochi kutumiza datagramyo kumalo ena oyimitsa panjira yopita. Ulalo wa netiweki utha kukhala topology kapena njira yofikira yomwe imathandizira mitsinje ya data ya IP.
4.The IP phukusi- -kusintha kwa deta
Chipangizo cha VoIP chomwe akupita chimalandira deta ya IP iyi ndikuyamba kukonza. Mulingo wa netiweki umapereka buffer yautali wosiyanasiyana womwe umagwiritsidwa ntchito kuwongolera jitter yopangidwa ndi netiweki. Buffer imatha kukhala ndi mapaketi amawu ambiri, ndipo ogwiritsa ntchito amatha kusankha kukula kwa buffer. Ma buffer ang'onoang'ono amatulutsa latency yocheperako, koma samawongolera jitter yayikulu. Chachiwiri, decoder imatsitsa paketi yamawu yosungidwa kuti ipange phukusi latsopano lamalankhulidwe, ndipo gawoli litha kugwiranso ntchito ndi chimango, kutalika kwake ndendende ndi decoder.
Ngati chimango kutalika kwake ndi 15ms, mapaketi a mawu a 60ms amagawidwa m'mafelemu 4, kenako amasinthidwanso kumayendedwe amawu a 60ms ndikutumizidwa ku decoding buffer. Panthawi yokonza lipoti la deta, chidziwitso choyankhulira ndi kulamulira chimachotsedwa, deta yoyambirira imasungidwa, ndipo deta yoyambirirayi imaperekedwa kwa decoder.
5.Kulankhula kwa digito kunasinthidwa kukhala mawu a analogi
Kusewera kosewera kumachotsa zitsanzo za mawu (480) mu buffer ndikuzitumiza ku khadi lamawu kudzera pa sipika pafupipafupi (mwachitsanzo 8kHz). Mwachidule, kutumiza kwa zizindikiro za mawu pa intaneti ya IP kumadutsa kutembenuka kuchokera ku chizindikiro cha analogi kupita ku chizindikiro cha digito, kuyika mawu adijito mu paketi ya IP, IP packet transmission kudzera pa intaneti, IP packet unpacking ndi kubwezeretsa mawu a digito ku analogi. chizindikiro.
Chachiwiri, mfundo zaukadaulo zokhudzana ndi VoIP
Pogwiritsa ntchito ma multimedia pamanetiweki olumikizirana omwe alipo, bungwe la International Telecommunication Union (ITU-T) lapanga protocol ya H.32x Multimedia communication series, mfundo zazikuluzikulu zotsatirazi zofotokozera mophweka:
H.320, Standard kwa matumizidwe ophatikizika amawu, nyimbo ndi zithunzi kulankhulana pa narrowband kanema telefoni dongosolo ndi terminal (N-ISDN);
H.321, Standard kwa matumizidwe ophatikizika amawu, nyimbo ndi zithunzi kulankhulana pa B-ISDN;
H.322. Muyezo wolumikizana ndi ma multimedia pa LAN wotsimikiziridwa ndi QoS;
H.323. Muyezo wolumikizirana ndi ma multimedia pamapaketi osinthira maukonde popanda chitsimikizo cha QoS;
H.324, muyezo wolumikizirana ndi ma multimedia pamayendedwe otsika kwambiri (PSTN ndi netiweki opanda zingwe).
Pakati pa miyezo yomwe ili pamwambayi, H. The 323 Standard-defined networks ndi omwe amagwiritsidwa ntchito kwambiri, monga Ethernet, Token Network, FDDI Network, etc.chifukwa cha H. Kugwiritsa ntchito 323 muyezo mwachibadwa kwakhala malo otentha pamsika, kotero m'munsimu tidzayang'ana pa H.323.H.323 Zigawo zinayi zazikuluzikulu zikufotokozedwa mu ndondomekoyi: terminal, gateway, gateway management software (yomwe imadziwikanso kuti gateway kapena gate), ndi multi-point control unit.
1. Pokwerera (pokwerera)
Ma terminal onse ayenera kuthandizira kulankhulana kwa mawu, ndipo mphamvu zoyankhulirana za kanema ndi deta ndizosankha.Zonse H. The 323 terminal iyeneranso kuthandizira H.245 Standard, H.245 Muyeso umagwiritsidwa ntchito kulamulira kagwiritsidwe ntchito ka tchanelo ndi kachitidwe ka tchanelo.H .323 Magawo akuluakulu a codec yamawu mukulankhulana kwamawu amatchulidwa motere: ITU inalimbikitsa bandwidth / KHz transmission bit rate / Kb/s compression algorithm annotation G.711 3.4 56,64 PCM compression yosavuta, yogwiritsidwa ntchito ku PSTN mu G .728 3.4 16 Khalidwe la mawu a LD-CELP ngati G.711, monga momwe amagwiritsidwira ntchito pamayendedwe otsika kwambiri G.722 7 48,56,64 ADPCM amawu apamwamba kuposa G.711, ogwiritsidwa ntchito pakutumiza kwa G. .723.1G.723.0 3.4 6.35.3 LP-MLQ Kumveka kwa mawu ndikovomerezeka, G.723.1 Adopt a G for VOIP forum.729G.729A 3.4 8 Kuchedwa kwa CS-ACELP ndikotsika kuposa G.723.1, Kumveka kwa mawu ndikokwera kuposa G.723.1.
2.Gateway (Gateway)
Iyi ndi njira ya H.An ya dongosolo la 323. Chipatacho chikhoza kusintha ndondomeko, ma audio, ma algorithms opangira mavidiyo ndi zizindikiro zoyendetsera ntchito zomwe zimagwiritsidwa ntchito ndi machitidwe osiyanasiyana kuti agwirizane ndi njira yolumikizirana.Monga PSTN-based H.324 System ndi narrowband ISDN yochokera ku H.The 320 System ndi H.323 Pakulumikizana kwadongosolo, ndikofunikira kukonza chipata;
3.Kusunga Customs (Mlonda)
Ichi ndi H.Chigawo chosankha cha dongosolo la 323 ndi pulogalamu yomaliza ntchito yoyang'anira.Ili ndi ntchito ziwiri zazikulu: yoyamba ndi H.323 Application management; chachiwiri ndi kasamalidwe ka kuyankhulana kwa terminal kudzera pachipata (monga kukhazikitsidwa kwa foni, kuchotsa, etc.) .Oyang'anira amatha kuchita kutembenuka kwa maadiresi, kuwongolera kwa bandwidth, kutsimikizira kuyimba, kujambula kuyimba, kulembetsa kwa ogwiritsa ntchito, kasamalidwe ka domain ndi ntchito zina kudzera mu miyambo. kusunga.one H.323 Malo olumikizirana amatha kukhala ndi zipata zingapo, koma chipata chimodzi chokha chimagwira ntchito.
4.Multipoint control unit (Multipoint Control Unit)
MCU imathandizira kuyankhulana kwazinthu zambiri pa intaneti ya IP, ndipo kuyankhulana kwa mfundo ndi mfundo sikofunikira.Dongosolo lonse limapanga topology ya nyenyezi kupyolera mu MCU.MCU ili ndi zigawo ziwiri zazikulu: multipoint controller MC ndi multipoint processor MP, kapena opanda MP.H pakati pa ma MC processing terminals.245 Lamulirani zambiri kuti mupange dzina laling'ono la anthu kuti azitha kumasulira mawu ndi makanema.MC simakonza mwachindunji uthenga uliwonse wapa media, koma imasiya kwa MP. MP amasakaniza, kusintha, ndikusintha mawuwo. , kanema, kapena zambiri za data.
M'makampani pali zomangamanga ziwiri zofanana, imodzi ndi ITU-T H yomwe yatchulidwa pamwambapa.323 Protocol ndi SIP protocol (RFC2543) yoperekedwa ndi Internet Engineering Task Force (IETF), ndipo protocol ya SIP ndi yoyenera kwambiri kwa ma terminals anzeru.
Chachitatu, kulimbikitsa chitukuko cha VoIP
Kugwiritsiridwa ntchito kwakukulu kwa VoIP kudzakwaniritsidwa mwamsanga chifukwa cha hardware zambiri, mapulogalamu, zochitika zokhudzana ndi chitukuko ndi chitukuko chaukadaulo mu protocol ndi standards.Kupita patsogolo kwaukadaulo ndi zomwe zikuchitika m'magawo awa zimathandizira kwambiri kupanga maukonde a VoIP ogwira ntchito, ogwira ntchito komanso ogwirizana. Zinthu zaukadaulo zomwe zimalimbikitsa kukula mwachangu komanso kugwiritsa ntchito VoIP kofala zitha kufotokozedwa mwachidule m'magawo otsatirawa.
1.Digital Signal Processor
Ma processor a digito apamwamba kwambiri (Digital Signal processor, DSP) amachita zinthu zofunika kwambiri pophatikiza mawu ndi data. mphamvu yogwiritsira ntchito ndi mtengo wotsika imapangitsa DSP kukhala yoyenera kuchita ntchito zopangira ma siginecha mu dongosolo la VoIP.
Liwu limodzi lokha pa G.729 Mtengo wa computing wa kukakamiza kwa mawu nthawi zambiri umakhala waukulu, umafuna 20MIPS. Ngati CPU yapakati ikufunika kuti igwire ntchito zoyendera ndi kasamalidwe ka makina pokonza mafunde angapo amawu, izi sizowoneka. Chifukwa chake, kugwiritsa ntchito DSP imodzi kapena zingapo kumatha kutulutsa ntchito yapakompyuta ya algorithm yovuta ya mawu kuchokera pakati pa CPU.Kuphatikiza apo, DSP ndiyoyenera kuzindikira zochitika zamawu ndi kuletsa kwa echo, kuwalola kuti azitha kukonza zowulutsira mawu munthawi yeniyeni ndikufikira mwachangu. pa board memory, so.Mu gawoli, tifotokoza mwatsatanetsatane momwe tingakhazikitsire kukodz mawu ndi kuletsa kwa maungo papulatifomu ya TMS320C6201DSP.
Protocol and standard software and hardware H.323 Weighted fair queuing method DSP MPLS tag exchange weighted randomly early discovered advanced ASIC RTP, RTCP dual funnel general cell rate algorithm DWDM RSVP voted access rate SONET Diffserv, CAR Cisco mofulumira kutumiza CPU processing mphamvu G. 729, G.729a: CS-ACELP Extended Access Table ADSL, RADSL, SDSL FRF.11/FRF.12 Token barrel aligorivimu Multilink PPP Frame Relay Data rectifier SIP yotengera kuphatikiza kwapadera kwa CoS Packet pa SONET IP ndi ATM QoS / CoS
2.Advanced odzipereka ophatikizidwa madera
Chitukuko cha Application-Specific Integrated Circait (ASIC) chapanga ASIC.ASIC yofulumira, yovuta, komanso yogwira ntchito kwambiri ndi chipangizo chapadera chomwe chimapanga ntchito imodzi kapena ntchito zochepa. amatha kukhathamiritsa kwambiri kuti azigwira ntchito zinazake, nthawi zambiri amakhala ndi zolinga ziwiri za CPU imodzi kapena zingapo za ukulu mwachangu.
Monga momwe Thin Instruction set Computer (RSIC) chip imayang'ana pakuchita mwachangu manambala a malire, ASIC imakonzedweratu kuti igwire ntchito zowerengeka mofulumira.Kupititsa patsogolo kukamalizidwa, mtengo wa ASIC kupanga misa ndi wotsika, ndipo umagwiritsidwa ntchito. kwa zipangizo maukonde kuphatikizapoma routersndi masinthidwe, kuchita ntchito monga kuyang'ana tebulo loyendetsa, kutumiza gulu, kusankha gulu ndi kufufuza, ndi kupanga mzere.Kugwiritsira ntchito ASIC kumapatsa chipangizocho ntchito yapamwamba komanso yotsika mtengo.Amapereka kuwonjezereka kwa burodi ndi chithandizo chabwino cha QoS pa intaneti, kotero iwo amasewera. gawo lalikulu polimbikitsa chitukuko cha VoIP.
3.IP kufala luso
Maukonde ambiri otumizira ma telecom amagwiritsa ntchito kugawa nthawi, pomwe intaneti imayenera kugwiritsa ntchito ziwerengero komanso kusinthanitsa mapaketi atali. Poyerekeza, chotsirizirachi chimakhala ndi kuchuluka kwa kugwiritsidwa ntchito kwazinthu zama netiweki, kulumikizana kosavuta komanso kothandiza, komanso kogwira ntchito kwambiri ku mautumiki a data, chomwe ndi chimodzi mwazifukwa zazikulu zakukula kwa intaneti. , kotero kukula kwa ziwerengero multiplexing paketi kuwombola anakopeka.Pakali pano, kuwonjezera pa mbadwo watsopano wa IP protocol-IPV6, World Internet engineering Task Group (IETF) akufuna multi-protocol tag exchange technology (MPLS), izi. ndi mtundu wamasanjidwe osanjikiza a netiweki kutengera ma tag / ma label osiyanasiyana, amatha kusintha kusinthasintha kwa kusankha kwa misewu, kukulitsa luso losankha maukonde, kuphwekarautandi kuphatikizika kwa kusinthana kwa njira, kuwongolera magwiridwe antchito a netiweki.MPLS imatha kugwira ntchito ngati njira yodziyimira payokha, komanso yogwirizana ndi njira yomwe ilipo kale, kuthandizira magwiridwe antchito osiyanasiyana, kasamalidwe ndi kasamalidwe ka ma network a IP, kupanga QoS, mayendedwe, ma signing ntchito bwino kwambiri, kufika kapena pafupi ndi mlingo wogwiritsanso ntchito ziwerengero zapaketi yapaketi yokhazikika (ATM), komanso yosavuta, yothandiza, yotsika mtengo komanso yogwiritsidwa ntchito kuposa ATM.
IETF ikugwiranso ntchito m'dera lanu ukadaulo watsopano wamagulu, kuti akwaniritse kusankha kwa msewu wa QoS. "Tekinoloje ya tunnel" ikuphunziridwa kuti ikwaniritse kufalikira kwa njira imodzi yolumikizirana. Kuphatikiza apo, momwe mungasankhire nsanja yotumizira ma network a IP ndi njira yolumikizirana. gawo lofunikira la kafukufuku m'zaka zaposachedwa, ndipo IP pa ATM, IP pa SDH, IP pa DWDM ndi matekinoloje ena adawonekera motsatizana.
Gawo la IP limapatsa ogwiritsa ntchito IP mautumiki apamwamba a IP omwe ali ndi zitsimikizo zina zautumiki. Wogwiritsa ntchito amapereka mawonekedwe olowera (IP access and broadband access) ndi mawonekedwe a service content. maukonde a IP, ndi nkhani, koma IP overDWDM ili ndi ukadaulo waposachedwa, ndipo ili ndi kuthekera kwakukulu kwachitukuko.
Dense Wave Division MultipLexing (DWDM) imalowetsa moyo watsopano muzitsulo zamagetsi ndipo imapereka bandwidth yodabwitsa m'makampani a telecom omwe amayika makina atsopano a fiber backbone.DWDM imagwiritsa ntchito mphamvu za optical fibers ndi zipangizo zamakono zotumizira. kuwala kwa kuwala (LASER) kuchokera kumtsinje umodzi wa optical fiber.Mawonekedwe amakono amatha kutumiza ndi kuzindikira 16 wavelengths, pamene machitidwe amtsogolo angathe kuthandizira 40 mpaka 96 wavelengths. chifukwa chake onjezerani maukonde a 2.6 Gbit/s (OC-48) ndi nthawi 16 popanda kuyala ulusi watsopano.
Maukonde ambiri atsopano amayendetsa OC-192 pa (9.6 Gbit / s), kupanga mphamvu yopitilira 150 Gbit / s pawiri ya ulusi pophatikiza ndi DWDM.Kuphatikiza apo, DWDM imapereka mawonekedwe a protocol ndi mawonekedwe odziyimira pawokha, ndipo imathandizira ma ATM onse awiri. , SDH ndi Gigabit Ethernet kufalitsa chizindikiro pa fiber imodzi, yomwe ingakhale yogwirizana ndi maukonde omwe alipo, kotero DWDM ikhoza kuteteza chuma chomwe chilipo, komanso kupereka makampani a ISP ndi telecom omwe ali ndi msana wolimba kwambiri, ndikupanga burodibandi kukhala otsika mtengo komanso opezeka, omwe amapereka. thandizo lamphamvu pazofunikira za bandwidth za mayankho a VoIP.
Kuchulukitsa kwapaipi sikungangopereka payipi yokulirapo yokhala ndi mwayi wocheperako wotsekereza, komanso kuchepetsa kuchedwa kwambiri, motero kungachepetse kwambiri zofunikira za QoS pamanetiweki a IP.
4.Broadband kupeza luso
Kufikira kwa ogwiritsa ntchito pa intaneti ya IP kwakhala cholepheretsa kukula kwa netiweki yonse.Kwa nthawi yayitali, cholinga chachikulu cha ogwiritsa ntchito ndi fiber-to-home (FTTH) . and passive optical network.Oyambawo ali makamaka ku United States, kuphatikiza ndi pakamwa lotseguka V5.1 / V5.2, kutumiza kachitidwe kake kaphatikizidwe pa fiber optical, kuwonetsa nyonga yayikulu.
Zotsirizirazi zimakhala makamaka mu dongosolo komanso ku Germany.Kwa zaka zoposa khumi, Japan yatenga njira zingapo zochepetsera mtengo wa ma network osawoneka bwino mpaka pamlingo wofanana ndi zingwe zamkuwa ndi zitsulo zopotoka, ndikuzigwiritsa ntchito. M'zaka zaposachedwa, ITU yapereka malingaliro a ATM-based passive optical network (APON), yomwe imakwaniritsa zabwino za ATM ndi network passive Optical. Mlingo wofikira ukhoza kufika ku 622 M bit / s, zomwe zimapindulitsa kwambiri pakupanga ntchito yamtundu wa Broadband IP multimedia, ndipo zimatha kuchepetsa kulephera komanso kuchuluka kwa node, ndikukulitsa kufalitsa.Pakali pano, ITU yamaliza ntchito yokhazikika , opanga akupanga mwachangu, padzakhala katundu pamsika, idzakhala njira yayikulu yachitukuko chaukadaulo waukadaulo wazaka za 21st.
Pakalipano, matekinoloje akuluakulu opeza ndi awa: PSTN, IADN, ADSL, CM, DDN, X.25 ndi Ethernet ndi mzere wofikira opanda zingwe opanda zingwe, etc.Matekinoloje opeza awa ali ndi makhalidwe awo, kuphatikizapo ADSL ndi CM yofulumira kwambiri; CM (Chingwe Modem) imagwiritsa ntchito chingwe cha coaxial, kuthamanga kwapamtunda, mphamvu zotsutsana ndi kusokoneza; koma osati kufala kwa njira ziwiri, palibe muyezo wofanana. ADSL (Asymmetrical Digital Loop) ili ndi mwayi wolumikizana ndi burodibandi, imagwiritsa ntchito mokwanira ma netiweki amafoni omwe alipo komanso kupereka kuchuluka kwa kutumizirana ma asymmetric. Mlingo wotsitsa kumbali ya wogwiritsa ntchito ukhoza kufika ku 8 Mbit / s, ndipo mlingo wa kukweza kwa wogwiritsa ntchito ukhoza kufika ku 1M bit / s.ADSL imapereka burodi yofunikira kwa malonda ndi ogwiritsa ntchito onse, ndipo imachepetsa kwambiri ndalama.Kugwiritsa ntchito ADSL yotsika mtengo madera, makampani tsopano amapeza intaneti ndi VPN yochokera pa intaneti pa liwiro lalikulu, kulola kuyimba kwa VoIP kwapamwamba.
5.Central processing unit technology
Central processing units (CPU) ikupitiriza kusinthika mu ntchito, mphamvu, ndi liwiro.Izi zimathandiza kugwiritsa ntchito ma multimedia PC ndikuwongolera machitidwe a machitidwe ochepetsedwa ndi mphamvu ya CPU. ndi ogwiritsa ntchito, kotero kutumiza maitanidwe a mawu pamanetiweki a data mwachibadwa ndicho cholinga chotsatira.Chinthu chogwiritsa ntchito pakompyutachi chimathandizira mapulogalamu apamwamba amtundu wa multimedia komanso zida zapamwamba pazigawo zapaintaneti kuti zithandizire kugwiritsa ntchito mawu.