.... 2 1.1... 2 1.2... 2 1.3... 2 1.4... 3 1.5... 3 1.6... 3 1.7... 4 1.8... 5... 5.... 7 2.1.... 7 2.2... 7 2.3 H.320... 8 2.4 H.323... 8 2. 5 H.320 H.323... 10 2.6... 13 2.7 MCU... 14.... 15 3.1.... 15 3.2.... 15 3.3.... 15 3.4.... 15 3.5... 15 3.6 POLYCOM... 16 2.7 POLYCOM... 16 1
. 1.1 1.2 PC 1.3 10 IEEE802.6 Ethernet Token-Ring Ethernet 50 T 50 UNIXNovellMicrosoft 100 UNIXNovellMicrosoft Token-Ring TOKEN TOKEN 2
1.4 1 ISO/OSI 01 OSI OSI 1.5 1 LAN WAN 2IP IP IP IP 1.6 3
ISDN ATM SMDS X.25 1.7 4
1.8 (H.320) ISDNDDNPCMVSAT (H.323) ATMIPFrame Relay WAN DDN ISDNDDN (Digital Data Network) 45.5bit/s 1984kbit/s DDN ISDN N*64Kbps ISDN Internet/Intranet TCP/IP IP IP (DDN) ISDN ATM ISDN BASBasic Access ServiceBRIBasic Rate InterfaceB channel64k2 D channel16k 144KB D BRI PASPrimary Access Service PRIPrimary Rate Interface 23 B 64K23=1472K D 64K 1536K AT&T T1 30 B 64K30=1920K D 64K 1984K ITU-T E1 PBX TE1 ISDN ISDN TE2 TA ISDN TE1 AMI line coding DDN DDN Digital Data Network Frame relay -- 5
ISDN X.25 :,, ;, DLCI, T1- T3- ISDNFRSFT TCP/IP FTP X.25Frame Relay 6
. 2.1. 55% 60% (Face to Face) 33% 38% 7%. 2.2 60 [AT&T] [Picturephone] 70 70 80 CODEC T1 CODEC 90 H.320 H.261 1992-1995 7
90 H.320 H.323 H.320 H.323 H.320 H.323 H.320 (QoS) H.323 QoS IP H.323 (RSVP) 2.3 H.320 ITU-T H.320 56Kbps 2Mbps ISDN 56Kbps 1990 H.320 ISDN H.320 " " ITU-T H.320 H.320 MCU H.320 H.200 T.120 ;H.200,.T.120 2.4 H.323 2.4.1 H.323 H.323 IP -----LAN INTRANET EXTRANET INTERNET H.323 ITU LAN ETHERNETFASTETHERNETTOKENRING ATM WAN ----ISDNV35E1/T1FRAMERELAYATM IP H.323 ISDN POTS PPP 1996 ITU H.323 H.323 ITU H.32X H.320 H.324 ISDN POTS IP LAN 10MBPS 100MBPS 1000MBPS H.323 IP QOS H.323 8
2.4.2 H.323 IP CTI INTRANET INTERNET / / 2.4.3 H.323 H.323 H.323 H.323 H.323 H.323 H.323 H.323 H.323 PPP IntranetExtranet Internet H.323 H.320H.324 ISDN H.323 H.323 H.323 H.323 9
H.323 / INTERNET. 2. 5 H.320 H.323 H.323 ( ) ( ) H.320 / TCP/IP TCP/IP MCU ( ) T.120 ( ) ( ) T.120 2.5.1 (ITU-T) H323 H320 2.5.2 TCP/IP Internet/Intranet TCP/IP TCP/IP 10
H323H323 TCP/IP ( )IP IP H323 H320H320 H320 ( MCU) 2.5.3 H323H323 H261 H263 G711 G722G728 G723.1G729aH320H323 H261 H263 G711 G722G728 H320 H323 2.5.4 H323H323 H323 ( H323MCU) LAN H323MCU (Web E-mail ) H320H320 H243 MCU ( ) MCU MCU ( ) H320 MCU 2.5.5 H323H323 H323 IP IP H323 IP H320H320 H320 H320 ( MCU) H320 ( ). 11
2.5.6 H323 H320 H323 H320 TCP/IP H320 H323 H320 H320MCU 2.5.7 H323 H323 TCP/IP IP IP Multicast(RFC1112) IP ( ) H323 IP H320H320 H320 ---- MCU / MCUMCU MCU 2.5.8 H323 H323 H320H320 () 2.5.9 H323 TCP/IP (Gatekeeper) H323 ( H323MCUGateway) H320 2.5.10 H323H323 TCP/IP H323 IP 12
( ) ( ) H320H320 (H323 ) H323/IP 2.6 2.6.1 PCM PALNTSC PAL/CIF CIF/PAL NTSC/CIF CIF/NTSC 2.6.2 2.6.3 : FCIF (352 x 288), QCIF, (Sub-QCIF, 4FCIF, 16FCIF) : 30, 15, 7.5 : n x 64Kbps n=130 ITU H.261 H.263 Sub-QCIF 128x96 QCIF 176x144 CIF 352x288 4CIF 702x576 N/A 16CIF 1408x1152 N/A 13
2.6.4 H.320-1990 ISDN H.321-1995 H.320 ATM/B-ISDN H.322-1995 H.320 Ethernet H.323-1996 H.324-1995 H.310-1996 ATM/B-ISDN T.120-1996 MEPG-I MEPG-II MEPG-IV H.261 H.263 G.711 G.722 G.723 G.728 G.729 MEPG-I Dolby AC-3 2.6.5 2.6.6 (Terminal) / (Gatekeeper) MCU( ) (Gateway) 2.7 MCU MCU,,,,,,,,,,,,, MCU 1 2 3. :,MCU 14
. Polycom Polycom Polycom 1998 ViewStation 3.1. ( ) 2584 Junction Avenue San Jose, CA 95134-1902 U.S.A +1.408.526.9000 : +1.408.526.9100 ( ) POLYSPAN TELECONFERENCING : ( ) ( ) ( ) ( ) 3.2. ( ) ( )( ), PLCM (NASDA) 3.3. www.polycom.com 3.4. ( 1998 12 31 ) 3.5 : 1998 1.11 140 1997 0.47 26 1996 0.37 48 1995 0.24 66 Polycom.,. 70. 280,000,. ViewStation 1998 ViewsStation 13,046. Polycom 20,000. 98 7. 15
. ( TeleSpan 18 35 ) 3.6 Polycom Polycom Robert C.Hagerty Hagerty Polycom Polycom Hagerty Connor Peripherals High Performance Allied Signals Ampex Video Recording Digital Equipment Brian L.Hinman Polycom Hinman PictureTe Hinman Dale A.Bastian Polycom Bastian Allen Bastian Rose Communications Digital Sound Commterm Code-A-Phone 17 Bastian Polycom 2.7 Polycom Polycom 1990 ( ) IP 175 OEM Polycom, 16