Txhawm rau siv cov ntawv xov xwm multimedia ntawm kev sib txuas lus uas twb muaj lawm, International Telecommunication Union (ITU-T) tau tsim H.32x multimedia kev sib txuas lus raws tu qauv. Hauv qab no yog cov lus piav qhia luv luv ntawm cov qauv tseem ceeb
H.320, tus qauv rau kev sib txuas lus multimedia ntawm qhov nqaim band video xov tooj thiab lub davhlau ya nyob twg (N-ISDN);
H.321, tus qauv rau kev sib txuas lus multimedia ntawm B-ISDN;
H.322, tus qauv ntawm kev sib txuas lus multimedia ntawm LAN tau lees paub los ntawm QoS;
H.323, tus qauv rau kev sib txuas lus multimedia ntawm pob ntawv hloov pauv tsis muaj QoS lav;
H.324, tus qauv rau kev sib txuas lus multimedia ntawm cov chaw sib txuas lus qis qis (PSTN thiab wireless network).
Ntawm cov qauv saum toj no, H.323 Standard txhais tau hais tias lub network yog qhov siv dav tshaj plaws, xws li Ethernet, token, FDDI, thiab lwm yam.vim yog daim ntawv thov ntawm H. 323 tus qauv tau dhau los ua qhov chaw kub hauv kev ua lag luam, yog li peb yuav tsom mus rau H.323.Cov lus pom zoo H.323 txhais tau plaub yam tseem ceeb: terminals, gateways, gateway management software (tseem hu ua gatekeepers lossis gateways), thiab multipoint control units.
1. Terminal
Txhua lub davhlau ya nyob twg yuav tsum txhawb nqa lub suab sib txuas lus, thiab lub peev xwm video thiab cov ntaub ntawv sib txuas lus yog xaiv tau.Txhua H.323 terminals yuav tsum txhawb nqa H.245 tus qauv, uas tswj cov kev siv channel thiab kev ua haujlwm.H.323 qhia txog qhov tseem ceeb ntawm lub suab codec hauv Lub suab sib txuas lus raws li nram no: ITU pom zoo lub suab bandwidth / KHz kis me ntsis tus nqi / Kb / s Compression algorithm annotation G.711 3.456,64 PCM yooj yim compression, siv rau PSTN G.728 3.416 LD-CELP hais lus zoo li G.711, Thaum thov mus rau tus nqi qis qis G.722 7 48,56,64 ADPCM kev hais lus zoo yog siab dua G.711, thaum siv rau kev sib kis tus nqi siab G.723.1G.723.0 3.4 6.35.3 LP-MLQ kev hais lus zoo tau txais G. .723.1 siv G.729 rau VOIP lub rooj sab laj. G.729a 3.48CS-ACELP ncua qis dua G.723.1, lub suab zoo siab dua G.723.1.
2. Rooj vag
Qhov no yog xaiv tau rau H.323 systems. Lub rooj vag tuaj yeem hloov pauv cov txheej txheem, suab thiab video coding algorithms thiab tswj cov cim siv los ntawm cov tshuab sib txawv kom haum rau kev sib txuas lus ntawm qhov system terminals. Raws li PSTN raws H.324 System thiab nqaim band ISDN raws H.320 System thiab H.323 System kev sib txuas lus, yuav tsum tau teeb tsa lub rooj vag.
3. Tus neeg saib xyuas
Qhov no yog ib qho kev xaiv ntawm H.323 system uas yog tswj los ntawm software. Nws muaj ob lub luag haujlwm tseem ceeb: ib qho yog tswj hwm H.323 daim ntawv thov; Qhov thib ob yog kev tswj hwm kev sib txuas lus ntawm lub davhlau ya nyob twg los ntawm lub rooj vag, xws li hu rau kev tsim, dismantling, thiab lwm yam. Tus thawj coj tuaj yeem ua qhov chaw nyob txhais lus, tswj bandwidth, hu rau authentication, hu rau cov ntaub ntawv, cov neeg siv sau npe, kev sib txuas lus tswj hwm thiab lwm yam haujlwm los ntawm Gatekeeper.An H.323 kev sib txuas lus sau tuaj yeem muaj ntau lub rooj vag, tab sis tsuas yog ib lub rooj vag tuaj yeem ua haujlwm.
4. Multipoint tswj chav tsev
MCU siv ntau qhov kev sib txuas lus ntawm IP network, tsis xav tau kev sib txuas lus point-to-point. Tsim tag nrho cov kab ke rau hauv lub hnub qub topology los ntawm MCU. MCU muaj ob yam tseem ceeb: multipoint maub los MC thiab multipoint processor MP, lossis tsis muaj MP. MC txheej txheem H.245 tswj cov ntaub ntawv ntawm cov terminals, tsim kom muaj ib qho me me npe npe rau kev ua suab thiab video. MC tsis ncaj qha ua cov ntaub ntawv xov xwm tshaj tawm, tab sis tso nws mus rau MP. MP sib tov, hloov, thiab ua cov ntaub ntawv suab, video, lossis cov ntaub ntawv.
Muaj ob qhov kev sib txuas ntawm tus xov tooj IP hauv kev lag luam, ib qho yog ITU-TH.323 raws tu qauv qhia saum toj no, lwm qhov yog SIP raws tu qauv (RFC2543) npaj los ntawm IETF, SIP raws tu qauv yog tsim nyog rau cov ntse davhlau ya nyob twg.
Cov ntsiab lus software ua haujlwm saum toj no yog rau pebONUseries network cov khoom lag luam hauv kev lag luam software, thiab cov khoom siv network kub muag khoom ntawm peb lub tuam txhab npog ntau homONUseries, suav nrog ACONU/ kev sib txuas lusONU/ ntseONU/ lub thawvONU/ dual PON chaw nres nkojONU, etc. Tag nrho cov saum toj noONUseries cov khoom siv tuaj yeem siv rau cov kev xav tau network ntawm txhua qhov chaw. Txais tos kom muaj kev nkag siab ntau ntxiv txog cov khoom.
