4 Xu hng phỏt trin K thut vin thụng Ni dung chớnh Chng I : C S K THUT TRUYN DN Chng II : C S K THUT CHUYN MCH Chng III: MNG VIN THễNG (+C S K THUT MNG IP V NGN) CHNG IV: XU HNG PHT TRIN CA CễNG NGH VIN THễNG Xu hng hi t ca cỏc mng v dch v vin thụng Cụng ngh truyn thoi qua IP Cụng ngh mng riờng o (VPN) Cỏc cụng ngh khỏc Cụng ngh khụng dõy v di ng Gii thiu chung v VoIP VoIP u nhc im Gim cc phớ dch v thoi ng di Nhiu cuc gi hn, gim rng bng thụng cho mi kt ni H tr thờm nhiu dch v b sung khỏc v giỳp trin khai cỏc dch v mi nhanh chúng, d dng, t ng dch v, phỏt hin trng thỏi, qun lý thụng tin, mó hoỏ bo mt S dng cú hiu qu nht giao thc IP: Tn dng u t, thit b sn cú vi nh iu hnh mng v cung cp dch v Thỏng nm 1995 hóng Vocaltec ó thc hin truyn thoi qua Internet, lỳc ú kt ni ch gm mt PC cỏ nhõn vi cỏc trang thit b ngoi vi thụng thng nh card õm thanh, headphone, mic, telephone line, speaker, modem phn mm ny thc hin nộn tớn hiu thoi v chuyn i thụng tin thnh cỏc gúi tin IP truyn dn qua mụi trng Internet Cú rt nhiu chun cho truyn thoi trờn nn IP nhng cú hai chun c s dng rng rói nht l H.323 ca ITU v SIP ca IETF VoIP: Cỏc gii phỏp mó húa ting núi Mó hoỏ dng súng; Mó hoỏ ngun; Mó hoỏ lai Codec Peak rate (kb/s) G.711 (PCM) 64 (no compression) G.726/G.727 G.728 (LD-CELP) G.729 (CS-ACELP) G.723.1 A-CELP MP-MLP 40/32/24 16 5,3 6,3 Packet size (bytes) Bandwidth (including overheads) Compression gain (relative to PCM/STM) 40(5ms) 142,4kb/s 0,45 160(20ms) 83,6kb/s 0,77 20(5ms) 110,4kb/s 0,58 80(20ms) 51,6kb/s 1,24 10(5ms) 94,4kb/s 0,68 40(20ms) 35,6kb/s 18 5(5ms) 86,4kb/s 0,74 20(20ms) 27,6kb/s 2,32 4(5ms) 83,5kb/s 0,77 16(20ms) 25,6kb/s 2,5 Bi tớnh toỏn bng thụng VoIP v h s nộn tng quan vi G.711 (PCM 64kb/s) ri so sỏnh vi bng G.711, mó 5ms G.729, mó 20ms G.723.1 mó 20ms VoIP: Cỏc giao thc v bỏo hiu VoIP: Cỏc gii phỏp mó húa ting núi VoIP: H.323 Chun H.323 cung cp nn tng cho vic truyn thụng thoi, video v d liu qua cỏc mng da trờn IP, bao gm c Internet H.323 l khuyn ngh ca ITU ni a cỏc chun truyn thụng a phng tin trờn cỏc mng LANs, cỏc mng ny khụng m bo cht lng dch v (QoS) SIP (Session Initiation Protocol) l mt giao thc iu khin tng ng dng cú th thit lp, trỡ v gii phúng cỏc cuc gi hoc cỏc phiờn truyn thụng Cỏc phiờn truyn thụng cú th l in thoi hi ngh, hc t xa, in thoi Internet v cỏc ng dng tng t khỏc VoIP-H.323 Chức H.323 Điều khiển hệ thống Audio Mạng IP In/Out Ngn xp giao thc VoIP-H.323 (Internet) Mã Audio 10 VoIP-H.323 Chuyển tải Chuyển đổi IP 11 VoIP - SIP SIP l mt giao thc chun IETF a nhm mc ớch thc hin mt h thng cú kh nng truyn qua mụi trng mng IP SIP da trờn ý tng ca SMTP v HTTP Nú c nh ngha nh mt client-server ú cỏc yờu cu c bờn gi (bờn client) a v bờn b gi (server) tr li nhm ỏp ng yờu cu ca bờn gi SIP s dng mt s kiu bn tin v trng mo u ging HTTP, xỏc nh ni dung thụng tin theo mo u c th ging nh giao thc c s dng trờn Web Assigned RFC 2543 vo thỏng 3/1999 12 13 VoIP - SIP VoIP - SIP SIP h tr dch v vic thit lp v kt thỳc cỏc phiờn truyn thụng: nh v ngi dựng: Xỏc nh v trớ ca ngi dựng tin hnh hi thoi Nng lc ngi dựng: Xỏc nh cỏc phng thc (phng tin) v cỏc tham s tng ng hi thoi Xỏc nh nhng ngi sn sng tham gia hi thoi Thit lp cỏc tham s cn thit cho cuc gi iu khin cuc gi: Bao gm c quỏ trỡnh truyn v kt thỳc cuc gi SIP Terminal (SIP phones) SIP Servers Location Server Redirect Server SIP Gateways Registral Server VoIP (H.323) ISDN PSTN User Agent Proxy Server Proxy Server Gateway 14 VoIP SIP mụ hỡnh tham chiu Application and System control TCP ntance message and presence Call hold Call transfer Other Data services services eg eg using PINT RTSP initial ISDN phone SIP-extensions SIP call header Methods Message body: SDP, PINT AV I/O equipment Audio Video RTP UDP IP 16 15 SIP V c bn cỏc bn tin SIP c chia lm hai loi: bn tin yờu cu (Request) bn tin ỏp ng (Respond) C hai loi bn tin ny u s dng chung mt nh dng c bn c quy nh RFC 2822 vi cu trỳc gm mt dũng u (start-line), mt s trng tiờu v mt phn thõn bn tin tu chn 17 User Agent 18 ỏnh s v a ch mng VoIP Internet: a ch IP, tờn vựng, a ch email PSTN: E.164 Thc t trin khai Vit Nam Proxy Server User Agen ACK Call Setup INVITE INVITE 302 ACK 180 (Ringing) 180 (Ringing) 200 (OK) 200 (OK) 200 (OK) Media Path Call Teardown INVITE 180 (Ringing) RTP Media Path BYE 200 (OK) 302: Moved Temporarily BYE 200 (OK) BYE 200 (OK) 20 Cỏc loi hỡnh dch v thoi qua IP Cỏc phng phỏp ỏnh s VoIP Location /Redirect Server INVITE INVITE SIPC ch hot ng 302 SIP Cu trỳc ny c túm tt nh sau: generic-message = start-line *message-header CRLF [ message-body ] Vi start-line = Request-Line / Status-Line Message-header = (general-header/Requestheader/Respone-header/entity-header) Trong ú, dũng u, cỏc dũng tiờu hay dũng trng phi c kt thỳc bng mt kớ t dũng trng, xung dũng (CRLF) v phi lu ý rng dũng trng phi cú ngn cỏch phn tiờu v thõn ca bn tin c phn thõn bn tin l rng Proxy Server u cui c PSTN: gi s E.164, thờm mó dch v Thit b mng GW, Router VoIP, GK, MCU: ỏnh a ch IP ca mng Internet 22 Phone to Phone (mỏy t ti mỏy t qua mng trung gian IP) PC to Phone (mỏy tớnh ti mỏy t) PC to PC (mỏy tớnh ti mỏy tớnh: cú th kt ni trc tip qua mng IP hoc cú th giỏn tip qua mng khỏc) 23 Phone to Phone (P2P) PC to Phone IP phone  PSTN PSTN IP network Gateway  PSTN Gateway Ă IP network  PSTN Gateway PC 24 PC to PC 25 Cỏc loi hỡnh dch v thoi qua IP Trin khai cỏc dch v VoIP ca VNPT IP phone IP phone Ă ê 3G phone IP network Ă ê 3G phone 26 Gi 171 (Phone Phone, cỏc dch v ca doanh nghip khỏc nh 178-Viettel, 177-Sfone, 179-EVN) Gi 1717: th tr trc cho cuc gi ng di nc v quc t Gi 1719: th tr trc cho cuc gi ng di nc v quc t, cú th gỏn ti khon c nh vo thuờ bao Fone VNN: PC2PC v PC2Phone 27 Mng riờng o (VPN-Virtual Private Network) u im ca VPN Mng riờng o VPN c nh ngha l mt kt ni mng trin khai trờn c s h tng cụng cng nh mng Internet vi cỏc chớnh sỏch qun lý v bo mt ging nh mng cc b Tit kim chi phớ Linh hot D dng m rng Gim thiu h tr k thut Gim thiu yờu cu v thit b S dng mng nn l IP/MPLS core, dch v VPN trờn nn IP l dch v cung cp cỏc kt ni ca cỏc chi nhỏnh ca cựng mt cụng ty Phớa ngi s dng ch cn cú ng truyn Internet qua h thng mng DSL l cú th truy cp c vo mng riờng ca cụng ty s dng dch v VPN 29 30 Mng ca tng lai : Mng tớch hp cựng vi s tớch hp cỏc phng thc truy nhp Giao thc bo mt PPTP VPN Customer Node Integrated End User Device (Voice, Data, Video, Multimedia) Network Node IP Based Network Access Network: DSL, Cable Modem, Wireless (Cellular, Wi-Fi, etc), Satellite, Other Thit b khỏch hng 32 Customer Premises Truy nhp Access Ni ht/khu vc Mng trc Local/Regional Backbone 36 Tham kho [1] in thoi IP Phựng Vn Vn 2002 [2] http://www.sipforum.org http://www.ietf.org/html.charters/sip-charter.html http://www.sipcenter.com [3] http://www.openh323.org/ [4] Virtual Private Networking and Intranet Security Copyright â 1999, Microsoft Corperation, Inc [5] Understanding Virtual Private Networking Copyrignt â 2001, ADTRAN, Inc [6] VPN Technologies: Sefinitions and Requirements Copyrignt â 2002, VPN Consortium 37