TRNG I HC QUY NHN

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TRNG I HC QUY NHNCNG HO X HI CH NGHA VIT NAM

KHOA K THUT & CNG NGHc lp T do Hnh phc

NHIM V

THIT K N TT NGHIPH v tn : Trnh H Dng H ao tao: Chnh Quy Kha: (2009 2014 ); Ngnh : in t - Vin thngB mn: in t - Vin thng

Khoa : K thut & Cng ngh

1. Tn tai thit k:

..

2. Cc s liu ban u:

3. Ni dung cc phn thuyt minh v tnh ton:

4. Cc bn v (ghi r cc loi bn v, kch thc bn v):

5. Cn b hng dn:

H tn cn b hng dn

Phn hng dn Ths L Th Cm H Ton phn6. Ngy giao nhim v thit k :

7. Ngy hon thnh nhim v :

Binh inh, ngy thng nm 2014

TRNG b MN CN b hng dn TRNG KHOA

Sinh vin hon thnh

Ngy thng .... nm 2014

Trnh H Dng

MC LCiMC LC

THUT NG VIT TTiv1LI NI U

3CHUNG 1: TNG QUAN V IPTV

31.1. Khi nim

51.2. Cu trc mng IPTV

51.2.1. C s h tng ca mng IPTV

61.2.1.2 Mng truy cp bng thng rng

61.2.1.3. Thit b khch hng IPTV (IPTVCD)

61.2.1.4. Mng gia nh

71.2.2. Cu trc chc nng cho dch v IPTV

71.2.2.1. Cung cp ni dung

81.2.2.2 . Phn phi ni dung

81.2.2.3 . iu khin IPTV

81.2.2.4. Chc nng vn chuyn IPTV

91.2.2.5. Chc nng thu bao

91.3. Vn phn phi IPTV

101.3.1. IP Unicast

121.3.2. IP Broadcast

121.3.3. IP Multicast

141.4. Cc cng ngh cho IPTV

141.4.1. Vn s l ni dung

151.4.2. VoD v Video server

171.4.3. Cc h thng h tr hot ng

191.5. Cc dch v v ng dng ca IPTV

191.5.1. Truyn hnh qung b k thut s

201.5.2. Video theo yu cu VoD

211.5.3. Qung co c a ch

22CHNG 2: CC K THUT PHN PHI MNG IPTV.

222.1. Cc loi mng truy cp bng rng

242.2.1. Mng quang th ng

262.2.1.1. BPON

272.2.1.2. EPON

272.2.1.3. GPON

282.2.2. Mng quang tch cc

282.3. IPTV PHN PHI TRN MNG ADSL

282.3.1. ADSL

312.3.2. ADSL2

312.3.3. VDSL

342.4.1. Tng quan v k thut HFC

362.4.2. IPTV phn phi trn mng truyn hnh cp

382.5. IPTV phn phi trn mng internet

382.5.1. Cc knh truyn hnh Internet streaming

402.5.2. Download Internet

412.5.3. Chia s video ngang hng

412.6. Cc cng ngh cho mng li IPTV

422.6.1. ATM v SONET/SDH

432.6.2. IP v MPLS

452.6.3. Metro Ethernet

48CHNG 3: QUN L MNG IPTV

483.1. H thng qun l mng IPTV

513.1.1. S dng giao thc SNMP qun l mng IPTV

553.1.2. Qun l thit b bng trnh duyt web

563.1. Qun l ci t

583.2. Gim st thc thi v kim tra mng

613.4. Qun l v d phng

623.5. Qun l khng gian a ch IP

643.6. X l cc s c IPTV

653.7. Qun l quyn ni dung s

673.8. Qun l cht lng dch v QoS

683.8.1. kh dng ca mng

683.8.2 Phn lp dch v

703.8.3. Cc cam kt cp dch v

71CHNG 4: TNH HNH PHT TRIN H THNG IPTV TI VIT NAM

724.1. Tnh hnh pht trin dch v IPTV ton cu

754.2. Gii thiu dch v- sn phm IPTV ca VNPT

754.2.1. Gii thiu dch v

794.2.2. Sn phm- dch v ca MyTV

804.3. Gii thiu dch v- sn phm IPTV ca FPT

834.4. Gii thiu dch v- sn phm IPTV ca VTC

884.5. Gii thiu dch v- sn phm IPTV ca Viettel

xviiKT LUN

xixTI LIU THAM KHO

THUT NG VIT TTT vit ttTing AnhTing Vit

A

ASApplication ServerMy ch ng dng

AVCAdvanced Video CodingM ho video tin tin

AONActive Optical NetworkMng quang tch cc

ATMAsynchronnuos Transfer Mode

Mode truyn dn bt ng b

B

BERBit Error RateT s li bit

B-RASBroadband Remote Access Server

My ch truy nhp t xa bng rng

C

CASConditional Access SystemH thng truy cp c iu kin

CATVCable TelevisionTruyn hnh cp

CBRConstant Bit RateTc bit c nh

CDMACode Division Multiple Accessa truy nhp phn chia theo m

CDNContent Distribution NetworkMng phn phi ni dung

CDRCall Detail RecordingBn ghi chi tit cuc gi

CMPQMColor Moving Picture Quality MetricThng s cht lng nh ng c mu

CNCore NetworkMng li

CPECustomer Premise EquipmentThit b pha khch hng

CSCFCall Session Control FunctionChc nng iu khin phin cuc gi

CSFContrast Sentivity FunctionHm nhy tng phn

CMTSCable Modem Termination SystemH thng kt cui modem cp

CPUCentral Processing Unit

n v x l trung tm

D

DFDelay FactorH s tr

DHCPDynamic Host Configuration ProtocolGiao thc cu hnh ng

DRMDigital Right ManagementQun l bn quyn s

DSLDigital Subscriber Lineng dy thu bao s

DSLAMDigital Subscriber Line Access MultiplexerB ghp knh truy nhp ng dy thu bao s

DVBDigital Video BroadcastingQung b video s

DVDDigital Video Disca video k thut s

DWDMDense Wavelength Division MultiplexingGhp knh phn chia theoMt bc sng

DVB-CDVB-CableDVB - cp

DVB-HDVB-HandheldDVB - cm tay

DVB-SDVB-SatelliteDVB - v tinh

DVRDigital Video Recorder

B ghi video s

E

EPGElectronic Program GuideCh dn chng trnh in t

ETSIEuropean Telecommunication Standard InstituteVin chun vin thng chu u

EVCEthernet Virtual Connection

Kt ni o Ethernet

F

FECForward Error CorrectionChnh li chuyn tip

FTTHFiber to the homeDy dn ti tn nh

FTPFile Transfer ProtocolGiao thc vn chuyn file

FTTCFiber To The CurdCp quang ti l ng

FTTNFiber To The NeighbourhoodCp quang ti vng ln cn

FTTROFiber To The Regional OfficeCp quang ti tng i khu vc

FTTPFiber to the Premise

Dy dn n tn ni

G

GPRSGeneral Packet Radio ServiceDch v v tuyn gi tng hp

GOPGroup of PictureNhm hnh nh

GIEGigabit Ethernet

Giao thc Gigabit Ethernet

H

HAHigh AvailabilityKh nng s dng cao

HDHight DefinitionCht lng cao

HDTVHigh Definition TelevisionTruyn hnh cht lng cao

HTTPHyper Text Transfer ProtocolGiao thc vn chuyn siu vn bn

HTTPSHyper Text Transfer Protocol SecureGiao thc HTTP bo m

HFCHybrid Fiber CoaxCp si lai

HGHome GatewayCng nh

HLRHome Location RegisterB ng k nh v thng tr

HSSHome Subscriber ServerMy ch thu bao thng tr

HTMLHypertext Markup Language

Ngn ng nh du siu vn bn

I

I-CSCFInterrogating-CSCFCSCF Truy vn

IETFInternet Engineering Task ForceNhm c trch k thut Internet

IMSIP Multimedia SubsystemPhn h a phng tin IP

IPInternet ProtocolGiao thc internet

IPRIntellectual Property RightsQuyn li ti sn tr tu

IPTVIP TelevisionTV giao thc internet

ITU-TInternational Telecommunications Union-Telecommunication Standardization SectorLnh vc tiu chun ho vin thng quc t

IPTVCDIPTV Cunsumer DeviceThit b khch hng IPTV

IRDIntegrated Receiver DecoderB gii m u thu tch hp

ISPInternet Service ProviderNh cung cp dch v

ISDNIntegrated Services Digital NetworkMng s dch v tch hp

IGMPInternet Group Management Protocol

Giao thc qun l nhm Internet

J

JVTJoint Video Team

Nhm video tng hp

L

LANLocal Area NetworkMng cc b

LSRLabel Switch RouterRouter chuyn mch nhn

LIRLabel Information Base

C s thng tin nhn

MMiddleware : Cc phn mm chc nng hoc dch v lin kt cc thnh phn c bit (v d nh server cc ng dng, VoD server v STB) v cc thnh phn ng dng (v d nh gim st truy cp c iu kin, h thng lp ha n v cc dch v tng tc)

MDIMedia Delivery IndexCh s phn phi phng tin

MGCFMedia Gateway Control FunctionChc nng iu khin cng phng tin

MLRMedia Loss RateT l mt phng tin

MMDMultimedia DomainMin a phng tin

MEFMetro Ethernet ForumDin n Metro Ethernet

MIBManagement Information BaseC s thng tin qun l

MOSMean Opinion Scoreim kin trung bnh

MPEGMoving Picture Experts GroupHi phim nh th gii

MPTSMulti Programme Transport StreamLung vn chuyn a chng trnh

MPQMMoving Pictures Quality MetricThng s cht lng nh ng

MRFCMultimedia Rource Funtion ControlB iu khin ti nguyn a phng tin

MPLSMulti-Protocol Label SwitchingChuyn mch nhn a giao

MSEMean Squared Error

Li trung bnh bnh phng

N

NGNNext Generation NetworkMng th h k tip

NMSNetwork Management SystemH thng qun l mng

NTSCNationalTelevision System Committeey ban h thng truyn hnh

P

PATProgram Association TableBng lin kt chng trnh

PCRProgram Clock ReferenceTham chiu ng h chng trnh

PIDPacket IdentificationNhn dng gi

PMTProgram Map TableBng nh x chng trnh

PONPassive Optical NetworkMng quang th ng

PSTNPublic Switched Telephone NetworkMng in thoi chuynmch cng cng

POTSPlain Old Telephone ServiceDch v in thoi truyn thng n gin

PCPersonal ComputerMy tnh c nhn

PPVPay-per-viewTr tin theo lt xem

PSPacket SwitchChuyn mch gi

PSIProgram Specific InformationThng tin ring phn chng trnh

PSNRPeak Signal To Noise RatioT s tn hiu nh trn nhiu

PSTNPublic Switched Telephone NetworkMng in thoi chuyn mch cng cng

PVRPersonal Video Recoder

My ghi hnh c nhn

Q

QoSQuality of ServiceCht lng dch v

QoEQuality of ExperienceCht lng tri nghim

QAMQuadrature Amplitude Modulation

iu ch bin cu phng

R

RTPReal time Transport ProtocolGiao thc truyn ti thi gian thc

RTSPReal Time Streaming ProtocolGiao thc phn lung thi gian thc

RFRadio Frequency

Tn s v tuyn

SStreaming : Phng thc phn phi video hoc ni dung khc trn mng trong cc lung ni tip nhau theo mt t l ph hp vi tc d liu c s dng bi thit b hin th

SCTPStream Control Transmission ProtocolGiao thc truyn ti iu khin lung

SDISerial Digital InterfaceGiao din dng s chui

SHESuper Head EndB u cui

SDStandard Definitionnh dng cht lng chun

SDHSynchronous Digital HierarchyGhp knh cp s ng b

SMILSynchronized MultimediaIntegrated LanguageNgn ng tch hp a phng tin ng b ha

SNMPSimple Network Management ProtocolGiao thc qun l mng n gin

SLAService Level AgreementTho thun mc dch v

SONETSynchronous Optical NetworkingMng quang ng b

SPTSSingle Program Transport StreamLung vn ti chng trnh n

STBSet Top Box

Hp t trn nc (TV)

T

TCPTransmission Control ProtocolGiao thc iu khin truyn dn

TDMTime Division MultiplexGhp knh phn chia theo thi gian

TDMATime Division Multiple Accessa truy nhp phn chia theo thi gian

TS(MPEG) Transport StreamLung vn ti

TTLTime to Live

Thi gian sng

U

UAUser AgentB phn ngi dng

UEUser EquipmentThit b ngi dng

URLUniversal Resource LocatorB xc nh a ch ti nguyn ton cu

UDPUser Datagram ProtocolGiao thc chng trnh ngi dng

V

VCRVideo Casette RecordingGhi li bng video

VoDVideo on DemandVideo theo yu cu

VoIPVoice over IPThoi qua IP

VLANVirtual Local Area NetworkMng LAN o

VPNVirtual Private NetworkMng ring o

VQMVideo Quality Metric

Thng s cht lng video

W

WANWide Area NetworkMng din rng

WLANWireless LANMng LAN khng dy

WDMWavelength Division MultiplexingGhp knh phn chia theobc sng

WMWindows MediaPhng tin Windows

DANH MC BNG

27Bng 2.1. So snh cc cng ngh mng PON: BPON, EPON v EPON

33Bng 2.2: So snh cc cng ngh DSL

43Bng 2.3 Cc chun OC SONET

44Bng 2.4 nh dng MPLS header

DANH MC HNH

5Hnh 1.1 M hnh h thng IPTV end-to-end

7Hnh 1.2 Cu trc chc nng cho dch v IPTV

9Hnh 1.3 Cc thnh phn ca cu trc chc nng

11Hnh 1.4 Cc kt ni Unicast cho nhiu user IPTV

13Hnh 1.5 Cc kt ni c s dng trong k thut Multicast

16Hnh 1.6 Cu trc h thng VoD

17Hnh 1.7 M hnh trin khai server

25Hnh 2.1 Mng IPTV FTTH s dng cng ngh PON

29Hnh 2.2. IPTV trn mng ADSL

35Hnh 2.3. Mng HFC end-to-end

37Hnh 2.4 M hnh trin khai cu trc mng IPTV cp quang kt hp IP v RF

39Hnh 2.5 Cu trc mng cc knh truyn hnh Internet.

42Hnh 2.6 H tng mng li IPTV

45Hnh 2.7 Topology mng li MPLS

47Hnh 2.8. S dng cc ECV kt ni IPTV qua li mng

52Hnh 3.1. H thng SNMP n gin

54Hnh 3.2 Lin kt h thng qun l mng IPTV

55Hnh 3.3 Cu trc qun l da trn trnh duyt web

61Hnh 3.4 Thit k mng h tr d phng

66Hnh 3.5: M hnh khi h thng DRMn gin.

67Hnh 3.6: Qun l cht lng dch v QoS.

70Hnh 3.7 V d s dng ba hng i c quyn u tin

76Hnh 4.4. Dch v- sn phm MyTv

76Hnh 4.5. Dch v truyn hnh trn internet

77Hnh 4.6. Dch v theo yu cu

78Hnh 4.7. Dch v tng tc v gi tr gia tng

73Hnh 4.1. Top 10 quc gia c doanh thu truyn hnh k thut s hng u vo nm 2017

74Hnh 4.2. D bo IPTV ton cu

74Hnh 4.3. Nhm 5 quc gia dn u v s thu bao chi tr cho IPTV.

79Hnh 4.8. B gii m STB ca MyTv

81Hnh 4.9. Dch v truyn hnh OneTV

81Hnh 4.10. Phim trn knh HBO

82Hnh 4.11. Mc phim truyn trn Onetv

83Hnh 4.12. Dch v ca nhc trn Onetv

84Hnh 4.13. Hp gii tr a phng tin ZTV ca VTC

86Hnh 4.14. Xem theo yu cu trn ZTV

88Hnh 4.15. Dch v gii tr trc tuyn

89Hnh 4.16. Sn phm- dch v NetTV ca Viettel

90Hnh 4.17. Chc nng xem 2 knh truyn hnh mt lc ca NetTV

90Hnh 4.18. Xem video, phim theo yu cu trn NetTV

LI NI U

Ngy nay, chng ta ang sng trong k nguyn ca truyn thng a phng tin,nhiu dch v, cng ngh hi t s c cung cp n ngi dng,trong khng th khng nhc n cng ngh IPTV.

IPTV l dch v truyn ti hnh nh k thut s ti ngi s dng da trn giao thc IP trn mng Internet kt ni bng thng rng,hin ang pht trin mnh m v tin ti v tr ch cht trong cng nghip truyn hnh thu ph v cng l dch v thu ht c s ch ca rt nhiu cc cng ty Vin thng trn th gii.IPTV ang l cp cao nht v l cng ngh truyn hnh thnh hnh ca tng lai. Khc vi cc cng ngh ca truyn hnh truyn thng ch c kh nng cung cp thng tin nh tuyn mt chiu th IPTV li c kh nng to ra tnh tng tc hai chiu gia khch hng vi dch v,to nn s hp dn v u th vt tri.IPTV l mt h thng nhiu tin ch,chng ta c th nhn cng lc c cc tn hiu truyn hnh v Video song song vi cc dch v a phng tin khc trn cng mt kt ni Internet. C th, IPTV s dng mt kt ni bng thng rng v mt h thng mng phn phi cc chng trnh truyn hnh s dng giao thc IP.

Trn th gii IPTV c trin khai mnh m v thu c li nhun rt ln.Ti Vit nam,IPTV tr ln kh gn gi i vi nhng ngi s dng Internet. IPTV c cng ty FPT tin phong cung cp dch v u tin vo thng 3/2006,n thng 5/2009 th VNPT bt u cung cp IPTV. Ngy nay, c thm nhiu cng ty khc nh SPT,VTC a IPTV, VoD.ra th trng. Nh vy, c th thy th trng IPTV ti Vit nam mi ch giai ot u cho nn tim nng v xu hng pht trin l rt ln.

Mong mun tm hiu nhng cng ngh mi ngy cng ng dng rng ri trong i sng,sau mt thi gian tm hiu cng vi s hng dn tn tnh ca c L Th Cm H, em c gng hon thnh n tt nghip vi ti Tm hiu cng ngh IPTV. Ni dung ca n c trnh by thnh 4 chng nh sau:

Chng I :Tng quan v IPTV

Chng II :Cc k thut phn phi trong mng IPTV

Chng III:Qun l mng IPTV

Chng IV: Tnh hnh pht trin h thng IPTV ti Vit Nam.

Do IPTV vn l mt cng ngh mi v kh nng kin thc cn hn ch nn qu trnh thc hin n khng trnh khi nhng thiu st,mong cc thy c gio cng cc bn thng cm,cng ng gp kin nhn xt b ch bn n ca em c hon thin hn.

Cui cng em xin gi li cm n su sc ti cc thy c gio tn tnh dy d em trong sut thi gian hc tp v lm n tt nghip,to iu kin tt em c th hon thnh n ca mnh.c bit,em xin chn thnh cm n c gio ThS L Th Cm H tn tnh hng dn v gip em trong qu trnh lm n tt nghip.

Em xin chn thnh cm n!

Bnh nh, ngythng nm 2014Sinh vin Trnh H Dng

CHUNG 1: TNG QUAN V IPTV

Truyn hnh da trn giao thc Internet IPTV (Internet Protocol

based Television) - l mt c ch truyn ti lung ni dung truyn hnh da trn nn tng l mt mng s dng giao thc IP. Li ch ca c ch ny l kh nng phn phi nhiu loi tn hiu truyn hnh khc nhau, tng cc tnh nng tng tc v ci tin tng tc v ci tin tng thch vi mng cc thu bao ang tn ti.

S pht trin nhanh chng ca mng Internet bng rng lm thay i c v ni dung v k thut truyn hnh. S vt tri trong k thut truyn hnh ca IPTV l tnh nng tng tc gia h thng vi ngi xem, cho php ngi xem ch ng v thi gian v kh nng trin khai dch v gi tr gia tng tin ch khc trn h thng nhm p ng nhu cu ca ngi s dng. y l xu hng hi t ca mng vin thng th gii.1.1. Khi nimIPTV truyn hnh s dng giao thc IP l mt h thng cc dch v truyn hnh s cung cp ti cc thu bao s dng giao thc IP trn kt ni bng rng. IPTV thng c cung cp cng vi dch v VoD v cng c th cung cp cung vi cc dch v Internet khc nh truy cp Web v VoIP.

Khi mi bt u IPTV c gi l truyn hnh giao thc Internet hay Telco TV hoc Truyn hnh bng rng. Thc cht tt c cc tn u c s dng ni n vic phn phi truyn hnh bng rng cht lng cao hoc ni dung m thanh v hnh nh theo yu cu trn mt mng bng rng. IPTV l mt nh ngha chung cho vic p dng phn phi cc knh truyn hnh truyn thng, phim truyn, v ni dung video theo yu cu trn mt mang ring. Theo t chc Lin Hip Vin Thng Quc T ITU th IPTV l dch v a phng tin bao gm truyn hnh, video, audio, vn bn, ha v d liu qua mt mng IP v c qun l cung cp mc yu cu ca cht lng dch v v s tri nghim, tnh bo mt, tnh tng tc v tin cy.IPTV c mt s im c trng sau: H tr truyn hnh tng tc: Kh nng ca h thng IPTV n cho php cc nh cung cp dch v phn phi y cc ng dng ca truyn hnh tng tc. Cc dng dch v IPTV c th c phn phi bao gm chun truyn hnh trc tip, truyn hnh hnh nh cht lng cao HDTV (High Definition Television), cc tr chi tng tc v truy cp Internet tc cao.

Dch thi gian: IPTV kt hp vi mt b ghi hnh video s cho php dch chuyn thi gian xem ni dung chng trnh, y l mt k thut ghi hnh v lu tr ni dung c th xem li sau.

Tnh c nhn: Mt h thng IPTV t kt cui n kt cui(end-to- end) h tr thng tin c tnh hai chiu v cho php cc user xem cc chng trnh theo s thch, thi quenHay c th hn l cho cc user xem ci g h mun vo bt k lc no.

Yu cu bng thng thp: thay th cho vic phn phi mi knh cho mi user, cng ngh IPTV cho php cc nh cung cp dch v ch phn phi cc knh m user yu cu. y l im hp dn cho php cc nh khai thc mng bo ton c bng thng ca h. Nhiu thit b c th s dng c: Vic xem ni dung IPTV khng gii han vic dng Tivi. Khchhinh 1 hng c th s dng PC ca h v cc thit b di ng truy cp cc dch v IPTV.

Nhng nhc im ch mng ca IPTV chnh l kh nng mt d liu rt cao v s chm tr truyn tn hiu. Nu nh ng kt ni mng ca ngi dng khng tht s tt cng nh khng bng thng cn thit th khi xem chng trnh s rt d b git hay vic chuyn knh c th tn kh nhiu thi gian ti v. Thm vo na nu my ch ca nh cung cp dch v khng mnh th khi s lng ngi xem truy cp vo olng lm cho cht lng dch v gim st. Tuy nhin cng ngh mng Internet cng ngy cng pht trin mnh m y bng thng kt ni ln cao hn gp phn gip IPTV khc phc nhc im ni trn v bin thnh cng ngh truyn hnh ca tng lai.1.2. Cu trc mng IPTV1.2.1. C s h tng ca mng IPTV

Hnh 1.1 M hnh h thng IPTV end-to-end1.2.1.1.Trung tm d liu IPTV

Trung tm d liu IPTV nhn ni dung t nhiu ngun khc nhau, bao gm truyn hnh a phng, cc nh tp hp ni dung, nh sn xut ni dung, qua ng cp, trm s mt t hay v tinh. Ngay khi nhn c ni dung, mt s cc thnh phn phn cng khc nhau t thit b m ha v cc my ch video ti b nh tuyn IP v thit b bo mt ginh ring c s dng chun b ni dung video cho vic phn phi qua mng da trn IP. Ngoi ra, h thng qun l thu bao c yu cu qun l h s v ph thu bao ca nhn ngi s dng.1.2.1.2 Mng truy cp bng thng rng

Vic truy cp cc dch v IPTV yu cu kt ni im-im(one-to- one).Vic trin khai IPTV trn din rng th s lng kt ni one-to-one s tng ln. Do , yu cu v bng thng trn mng l kh ln. Nhng tin b v cng ngh mng cho php cc nh cung cp vin thng p ng c mt s lng ln v rng bng thng ca mng. Ring mng truyn hnh cp th s dng hn hp c cp ng trc v cp quang a ng cho vic truyn ti ni dung IPTV.1.2.1.3. Thit b khch hng IPTV (IPTVCD)

IPTVCD( IPTV Consumer Device) l cc thnh phn quan trng cho php ngi s dng c th truy cp dch v IPTV. IPTVCD kt ni ti mng bng rng, chng m nhim chc nng gii m, x l cc lung tn hiu ti da trn gi IP. IPTVCD c h tr cc k thut tin tin ti thiu ha hoc loi tr hon ton nh hng ca cc vn v mng khi x l ni dung IPTV. Cc loi IPTVCD ph bin nht l RG, IP set-top-box. Trong RG l modem ADSL v modem cp trn mng truyn hnh cp hai chiu HFC. 1.2.1.4. Mng gia nh Mng gia nh lin kt cc thit b k thut s bn trong mt khu vc c din tch nh. N ci thin thng tin v cho php chia s ti nguyn gia cc thnh vin trong gia nh. Mc ch ca mng gia nh l cung cp quyn truy cp thng tin nh l ting ni, m thanh, d liu, gii tr, gia cc thit b k thut s xung quanh nh. Vi mng gia nh, khch hng c th tit kim tin v thi gian do vic chia s cc thit b phn cng rt tt v d dng, thng qua cc kt ni Internet bng rng.1.2.2. Cu trc chc nng cho dch v IPTV

Mt mng IPTV c th bao gm nhiu thnh phn c bn, n cung cp mt cu trc chc nng cho php phn bit v chuyn mn ho cc nhim v

Hnh 1.2 Cu trc chc nng cho dch v IPTV1.2.2.1. Cung cp ni dung

Tt c ni dung c s dng bi dch v IPTV, bao gm VoD v ruyn hnh qung b s phi thng qua chc nng cung cp ni dung, cc chc nng tip nhn, chuyn m v m ha s to nn cc lung video s c kh nng c phn phi qua mng IP.

1.2.2.2 . Phn phi ni dungKhi phn phi ni dung bao gm cc chc nng chu trch nhim v vic phn phi ni dung c m ho ti thu bao. Thng tin nhn t cc chc nng vn truyn v iu khin IPTV s gip phn phi ni dung ti thu bao mt cch chnh xc. Chc nng phn phi ni dung s bao gm c vic lu tr cc bn copy ca ni dung tin hnh nhanh vic phn phi, cc lu tr tm thi (cache) cho VoD v cc bn ghi video c nhn. Khi chc nng thu bao lin lc vi chc nng iu khin IPTV yu cu ni dung c bit, th n s gi ti chc nng phn phi ni dung c c quyn truy cp ni dung.

1.2.2.3 . iu khin IPTVCc chc nng iu khin IPTV l tri tim ca dch v. Chng chu trch nhim v vic lin kt tt c cc chc nng khc v m bo dch v hot ng cp thch hp tho mn nhu cu ca khch hng. Chc nng iu khin IPTV nhn yu cu t thu bao, lin lc vi chc nng phn phi v vn chuyn ni dung m bo ni dung c phn phi ti thu bao. Mt chc nng khc ca iu khin IPTV l cung cp hng dn chng trnh in t EPG (Electronic Program Guide), EPG c thu bao s dng chn ni dung theo nhu cu. Chc nng iu khin IPTV cng s chu trch nhim v qun l quyn ni dung s DRM (Digital Rights Management) c yu cu bi thu bao c th truy cp ni dung.

1.2.2.4. Chc nng vn chuyn IPTV

Sau khi ni dung yu cu t thu bao c chp nhn, chc nng vn chuyn IPTV s chu trch nhim truyn ti ni dung ti thu bao, v cng thc hin truyn ngc li cc tng tc t thu bao ti chc nng iu khin IPTV.1.2.2.5. Chc nng thu bao

Chc nng thu bao bao gm nhiu thnh phn v nhiu hot ng khc nhau, tt c u c s dng bi thu bao truy cp ni dung IPTV. Mt s thnh phn chu trch nhim lin lc thng tin vi chc nng truyn dn, v d nh truy cp getway kt ni vi b ghp knh truy cp ng dy thu bao s DSLAM, hay trnh STB (b gii m) s dng trnh duyt web kt ni vi Middleware server. Trong chc nng ny, STB lu tr mt s cc thnh phn quan trng nh cc key DRM v thng tin xc thc user. Khi chc nng thu bao s s dng EPG cho php khch hng la chn hp ng truy cp v y cu n t cc chc nng iu khin IPTV. N cng nhn cc giy php s v cc key DRM truy cp ni dung.

Hnh 1.3 Cc thnh phn ca cu trc chc nng1.3. Vn phn phi IPTVCc kiu lu lng mng IP thi gian thc khc nhau c to ra bi cc loi dch v trn nn IP khc nhau nh VoIP v truy cp Internet tc cao. Vi mi loi dch v c nhng c im ring v ni dung, v th cn phi c nhng phng thc phn phi thch hp. Hin nay c ba phng thc dng phn phi ni dung IPTV qua mng IP l unicast, broadcast v multicast.

IP Unicast: c s dng truyn d liu (hay mt gi d liu) tmt my pht (sender) n mt my thu n gin. IP Broadcast: c s dng gi d liu t mt my pht (sender) n ton b mt mng con Subnetwork gm nhiu my thu.

IP Multicast: c s dng cung cp d liu t mt my pht n mt nhm cc my thu c ci t theo mt cu hnh thng nht, cc thnh vin ca mt nhm ny c th thuc cc mng phn tn khc nhau.

Tuy nhin, i vi vn truyn dn video trong mi trng mng, do yu cu phi phn phi d liu t mt im n nhiu im, trong dng d liu cn c truyn i t mt my pht sender n nhiu my thu c nhu cu xem ng thi, nhng li khng c php i n ton b cc my c kt ni trong cng mt mng con subnetwork ( gim lu lng lu thng trn mng), nn gii php IP Boradcast thng t c s dng trong thc t. Cc ng dng truyn dn truyn hnh trn mng hin nay thng s dng phng php IP Unicast v IP Multicast, trong IP Multicast l gii php hin ang c ng dng kh ph bin hin nay.

1.3.1. IP Unicast

Mt s ng dng truyn thng cc chng trnh truyn hnh trn mng giai on u s dng phng php truyn d liu IP Unicast. Trong truyn unicast, mi lung video IPTV u c gi ti mt IPTVCD. V th, nu c nhiu hn mt user IPTV mun nhn knh video tng t th IPTVCD s cn ti mt lung unicast ring r. Mt trong cc lung s truyn ti cc im ch qua mng IP tc cao. Nguyn tc thc thi ca unicast trn mng IP l da trn vic phn phi mt lung ni dung c nh hng ti mi user u cui. T gc ca k thut ny, th vic cu hnh thc thi kh d dng. Nhng cc ng dng ny mang nhiu hn ch v hin nay t c ng dng v nhiu l do sau:

Bng thng ca mng b lng ph.

Dch v rt kh m rng khi s lng my thu tng ln.

Khng th s dng trong cc dch v b gii hn thi gian, do s cung cp n mi my thu phi theo trnh t xp hng.

Hnh 1.4 Cc kt ni Unicast cho nhiu user IPTVNh trn hnh 1.4, khi nhiu user IPTV truy cp cng mt knh IPTV ti cng mt thi im, th mt s cc kt ni nh hng c thit lp qua mng.Trong v d ny, server cn cung cp kt ni ti mi thu bao c yu cu truy cp Knh10,vi tng s l nm lung ring r bt u t server ni dung v kt thc ti router ch.

1.3.2. IP BroadcastCc mng IP cng h tr chc nng truyn broadcast, v mt no ging nh knh IPTV c a ti mi thit b truy cp c kt ni vo mng bng rng. Khi mt server c cu hnh truyn broadcast, mt knh IPTV gi ti tt c cc thit b IPTVCD c kt ni vo mng bt chp thu bao c yu cu knh hay khng. y s l vn chnh do cc ti nguyn IPTVCD bt buc phi hot ng x l cc gi tin khng mong mun. Mt vn khc m broadcast khng ph hp cho cc ng dng IPTV l trong thc t k thut truyn thng tin ny khng h tr vic nh tuyn. T lu, hu ht cc mng m rng vic s dng cc router, nhng nu truyn broadcast th khng s dng nh tuyn. y l l do lm mng v cc thit b IPTVCD khc b trn ngp khi tt c cc knh c gi ti tt c mi ngi.1.3.3. IP MulticastTrong phm vi trin khai IPTV, mi nhm multicast c truyn broadcast cc knh truyn hnh v thnh vin ca nhm tng ng vi cc thit b IPTVCD. V th, mi knh IPTV ch c a ti IP STP mun xem knh . y l cch hn ch c lng tiu th bng thng tng i thp v gim gnh nng x l trn server. Hnh 1.5 m t hot ng ca vic s dng k thut multicast trong v d phn phi cho nm thu bao truy cp knh 10 IPTV cng mt lc.

Hnh 1.5 Cc kt ni c s dng trong k thut Multicast

Nh hnh 1.5 ch bn copy n (single) c gi t server ni dung ti router phn phi. Router ny s to ra hai bn copy ca lung thng tin ti v gi chng ti cc router t ti cc tng i khu vc theo cc kt ni IP nh hng. Sau , mi router s to ra cc bn copy khc cung cp cho cc thu bao mun xem. Vai tr quan trng ca phng thc ny l lm gim s kt ni IP v dung lng d liu i ngang qua mng. y l phng thc thng c cc nh cung cp dch v s dng pht qung b cc chng trnh trc tip v l mt k thut c hiu sut cao cho h tng mng IP ang tn ti. Phng thc ny khng c li trong tuyn hng ln (upstream) lung thng tin gia cc thit b IPTVCD v broadcast server. Cn ch rng, vic pht multicast ni dung IPTV thng phc tp hn nhiu nu so snh vi m hnh thng tin unicast v broadcast.

So snh cc phng thc phn phi IPTV

IP Unicast: Nh trnh by trn, do cc nhc im lng ph bng thng, kh m rng dch v khi con s khch hng tng ln, nht l trong cc dch v b gii hn v thi gian (nh truyn hnh online), nn IP Unicast khng tht s thch hp cho dch v truyn hnh trn mi trng mng.

IP Multicast: So IP Unicast, truyn thng IP Multicast cho php phn phi d liu t mt im n nhiu im vi hiu qu bng thng cao hn rt nhiu, nhng vn tn ti mt s vn nh:

Cc b nh tuyn trung gian (Router) cn phi c kh nng multicast.

Yu cu cao v tnh nng thit b v nng lc qun tr mng. Vn tin cy v kh nng kim sot li truyn d liu.Cc yu cu lin quan n cc my thu: Cn c Card mng v phn mm h tr IP Multicast.

Nhn chung, i vi cc dch v truyn hnh trc tuyn trn mi trng mng c nhu cu m rng khng ln lm, IP Multicast vn l phng thc truyn thng ph bin hin nay.

IP broadcast: Trong thc t k thut truyn thng tin ny khng h tr vic

nh tuyn v th m broadcast khng ph hp cho cc ng dng IPTV.

1.4. Cc cng ngh cho IPTV1.4.1. Vn s l ni dung

Cc h thng x l ni dung tip nhn cc tn hiu video thi gian thc t rt nhiu ngun khc nhau, hnh thc ca chng l mt nh dng thch hp STB c th gii m v hin th trn mn hnh. Tin trnh ny bao gm cc chc nng sau:

Nn: Cc ngun video tng t, qu trnh nn s c thc thi trn mi tn hiu video trc khi n c pht ln h thng IPTV. Tc cao nht ca d liu video v di ca gi tin c thc hin sao cho ph hp vi tt c cc ngun video u vo, v n gin ha cng vic truyn dn v cc chc nng ghp knh.

Chuyn m: Cc lung video tng t c nh dng s, i khi n cn c chuyn i sang thuc tnh MPEG hoc cp lung ti thch hp vi cc b STB. Chuyn m ni dung nh dng HD cung cp cc chun chuyn m gc l MPEG-2 thnh H.264 c c bng thng thp hn cho cc mng DSL.

Chuyn i tc : Bn cht ca vic chuyn i tc l tin trnh chuyn i tc bit ca lung video s ti. V d nh lung chun SD l 4,5 Mbps c th cn phi gim xung 2,5 Mbps s dng trong h thng IPTV. Nhn dng chng trnh: Mi lung video cn c ghi mt nhn duy nht trong h thng IPTV, do cc thit b ghp knh v cc b STB c th xc nh chnh xc cc lung video. Mi chng trnh audio hay video bn trong mi lung truyn dn MPEG phi c x l m bo khng c s trng ln chng trnh. Vic x l ni dung c th c thc thi trn mt lung video trc tip hoc c lu tr bn trong video server.

1.4.2. VoD v Video serverVoD (video on demand) truyn hnh theo yu cu l cch thc ngi xem cc chng trnh truyn hnh theo s la chn ca khn gi.Cu trc ca h thng VoD s dng cng ngh video-over-IP trn hnh 1.6 bao gm 4 thnh phn chnh. u tin, ni dung phi c x l cho vic lu tr v phn phi bng qu trnh nn v mt m ti trm tin x l ni dung. Mt VoD server lu tr ni dung v to lung gi ti thu bao. Mi thu bao s c mt b STB nhn v gii m ni dung, sau a ln mn hnh hin th. B STB cng cung cp cho thu bao mt danh sch cc dch v t thnh phn qun l thu bao v h thng truy cp c iu kin. y l mt h thng con nhn cc lnh t thu bao, gi nhng lnh thch hp ti VoD server v phn phi cc key gii m cho cc b STB.

Hnh 1.6 Cu trc h thng VoD Cc video server l yu t cn thit cho mi h thng VoD, do

chng to ra cc lung video trong thc t v gi chng ti mi thu bao. Cc server c dung lng b nh ln nh khc nhau ty thuc vo cc ng dng khc nhau. Trong phn ny ch cp n mt s kha cnh ca cc server v cch thc chng c s dng cho vic phn phi ni dung. Dung lng lu tr ni dung c h tr trn mt server c th ln hoc nh.

Cc nh cung cp s dng hai phng thc phn phi server trong mng ca h, nh trn hnh 1.7. u tin l phng thc tp trung ha, cc server ln,dung lng cao c xy dng ti nhng v tr trung tm, chng phn phi ni dung cho thu bao thng qua cc lin kt tc cao kt ni ti mi nh cung cp dch v ni ht. Phng thc th hai l phn phi ha server, cc server nh hn c t ti cc v tr gn thu bao v server ch cung cp cho cc thu bao trong vng .Trung tm Library server s download cc bn copy ni dung cung cp cho cc Hub server phn phi c yu cu. Trong phng thc tp trung ha th gim c s lng server cn phi xy dng, gim gi thnh trong vic truyn dn v lu tr ni dung ti cc v tr khc nhau. Cn trong phng thc phn phi ha th gim c s lng bng thng cn thit gia cc v tr. C hai phng thc u c s dng trong thc t, dung lng ca VoD server ph thuc vo cu trc h thng v s thch ca ngi xem.

Hnh 1.7 M hnh trin khai server1.4.3. Cc h thng h tr hot ng

Vic phn phi cc dch v video ti khch hng yu cu nhiu thit b phn cng c tin cy cao. Mt phn mm ln cng c yu cu qun l s lng cng vic khng l , t vic thng bo cho khch hng v cc chng trnh trn cc knh broadcast khc nhau cho ti d liu cn thit cho vic lp ha n cc dch v m khch hng ng k. Tp trung li, cc h thng phn mm ny gi l h thng h tr hot ng OSS (Operations Support Systems) v n c th bao gm nhiu dng khc nhau. Mt s chc nng c cung cp bi cc h thng IPTV OSS nh sau:

Hng dn chng trnh in t EPG (Electronic Program Guide) cung cp cho ngi xem lch pht knh broadcast v tn cc chng trnh VoD sn c. Hng dn ny c th bao gm c cc knh broadcast thng qua vic la chn chng trnh hoc hng dn chng trnh tng tc cho php user ln lch cc knh c pht trong tng lai. Mt s cc nh khai thc dch v IPTV s dng cc cng ty bn ngoi cung cp d liu hng dn chng trnh.

H thng phn quyn c yu cu khi cc thu bao ng k xem ni dung thng qua h thng IPTV. H thng ny cn c kh nng kim tra

thng tin ti khon ca khch hng, l cn c h thng phn quyn c th p ng cc yu cu ca thu bao hay khng. H thng ny cn kt ni vi h thng lp ho n thu bao. Truy cp ni dung trc tuyn (e-mail, web) c cung cp bi mt s h thng IPTV, cho php user c th xem ni dung trn PC tng t nh xem trn Tivi nhng khng cn b gii m IP STB.

H thng lp ho n v qun l thu bao s bo qun d liu chnh v mi thu bao, bao gm hp ng, cc chi tit ho n, cc trng thi ti khon, v cc thng s nhn dng thit b.

Cc h thng OSS c th l thnh phn u t chnh ca cc nh cung cp dch v IPTV v c thi gian ln tin bc. Bi v n m bo cc phn mm cn thit c mua t nhiu nh cung cp khc nhau s thc thi y cc chc nng c la chn bi nh cung cp. Vic tch hp cc h thng ny c th mt nhiu thng, v nhiu cng vic cn c hon thnh trc khi cung cp dch v cho s lng ln thu bao. Hn na, cc chi ph trn l yu t c nh gi d dch v thu ht c 1000 hay 100000 thu bao. Cng nh vy, chi ph lp t cc h thng OSS cn c xem xt cn thn trong k hoch kinh doanh ca cc nh cung cp dch v, vic tnh ton chi ph lp t OSS nm trong giai on u tin ca k hoch trin khai, cc chi ph ny c th vt tri gi thnh ca phn cng h thng cho s lng thu bao thp hn. Hn na, gi thnh bo dng c s d liu s khng c xem xt khi trin khai m hnh kinh doanh cho mt h thng IPTV.1.5. Cc dch v v ng dng ca IPTV Mt trong nhng mt hp dn nht ca IPTV, xem xt t kha cnh cng ty in thoi l n cho php cc nh cung cp dch v mt s cc ng dng vi c s cng ngh v mc u t tng ng. Hn na, IPTV c th kt hp vi mt mng IP bng rng mi hoc c sn c s dng cung cp cc dch v s liu. Rt nhiu cc ng dng ny c th c cung cp mc gi thp hn so vi gi cung cp ni dung truyn hnh thng mi chnh thng cho php cc nh cung cp c sc cnh tranh hn.

Nhng trong phn ny ch trnh by mt s dch v c trin khai bi cc nh cung cp dch v IPTV ti Vit Nam. l truyn hnh qung b k thut s, dch v VoD v qung co c a ch.1.5.1. Truyn hnh qung b k thut s

Khch hng s nhn c truyn hnh s thng thng bng IPTV. Truyn hnh qung b s c phn phi ti thu bao thng qua truyn hnh cp c nng cp hoc h thng v tinh. S khi u ca cc cng ngh DSL tc cao hn nh ADSL2 v ADSL2+ mang n mt cuc cch mng ln trong lnh vc ny. Vi cc cng ngh tc cao ny cho php IPTV c thm tin cy v tnh cnh tranh vi cc dch v truyn hnh thu ph khc.

IPTV c y kh nng a ra cc dch v cht lng cao khc nhau v nhiu dch v hn so vi cc nh cung cp truyn hnh thu ph cp v v tinh trong qu kh. Mt li ch khc ca IPTV l n c nhiu ni dung v s knh ln hn la chn, ty thuc vo s thch ca khch hng. c bit khch hng c th t chn la ngun ni dung a dng ny.

Chc nng ca truyn hnh qung b thng thng, truyn hnh cp v v tinh l cung cp tt c cc knh ng thi ti nh thu bao. Tuy nhin, IPTV ch phn phi cc knh m khch hng mun xem v n c kh nng cung cp khng gii hn s knh ny. Khch hng s t do iu khin nhng g h mun xem v xem vo bt c lc no h mun. y l c tnh vn c v c th xy ra ca IPTV v n c s kt hp ca kh nng tng tc hai chiu trn nn mng IP.

1.5.2. Video theo yu cu VoD

VoD l dch v cung cp cc chng trnh truyn hnh da trn cc yu cu ca thu bao. Cc dch v truyn hnh c pht i t cc b lu tr phim truyn, chng trnh gio dc hay tin tc thi s thi gian thc. ng dng VoD cung cp cho tng thu bao ring l chn ni dung video v h xem n vo lc thch hp nht.

Khi h tng mng IPTV u tin c thit k th cc ng dng v cc dch v to li nhun nh in thoi video, hi thoi truyn hnh, o to t xa v camera gim st an ninh ti nh u c th cung cp cho khch hng. C thm mt s dch v v c tnh tin tin hn so vi h thng truyn hnh qung b truyn thng.

1.5.3. Qung co c a ch

Thng tin tin nhn c bit hoc ni dung a phng tin gia thit b v khch hng da trn a ch ca h gi l qung co c a ch. a ch c cng b ca khch hng c th bit c thng qua vic xem xt k profile ca ngi xem. N c thc hin bi lnh xc nh d tin nhn qung co ph hp hoc khng ph hp vi ngi nhn. V th, qung co c a ch cho php tnh ton nhanh chng v chnh xc hiu qu ca chin dch qung co.

S hp tc ca ngi xem l din mo ca qung co c a ch. Ngay khi truyn hnh IP c bt u, cc h thng truyn hnh IP c th hi hoc nhc nh ngi xem khai bo tn ca h t danh sch ng k. i li, ngi xem s mun chn tn chng trnh ca h. Ti y, tn chng trnh c mt profile v cc tin nhn qung co c th c la chn, cch xem tt nht l kt ni ti profile ca ngi xem. Bi v, cc c tnh tin tin c a ra ca truyn hnh IP v d nh cc cuc gi ti, e-mail v hng dn chng trnh u nh cc knh u thch, ngi xem c th thc s xem chng.

Thu nhp c to ra bng cch gi cc tin nhn c a chi ti ngi xem, vi cc profile c bit c th ln gp 10 n 100 ln thu nhp t qung co qung b thng thng. Kh nng gi cc qung co thng mi ti mt s ngi xem c bit cho php cc nh qung co c nh c qu u t chnh xc cho qung co c a ch. N cng cho php cc nh qung co th nghim mt s qung co thng mi khc trong cng mt vng ti cng mt thi im.CHNG 2: CC K THUT PHN PHI MNG IPTV. Hin nay IPTV c nhn nhn nh l con ng tt nht phn phi

cc dch v truyn hnh k thut s cho khch hng. Bn cht ca IPTV l mt mng phn phi tc cao c lm nn mng phn phi ni dung. Mc ch ca mng ny l truyn ti d liu gia thit b khch hng IPTVCD v trung tm d liu ca cc nh cung cp dch v. N cn lm vic ny m khng nh hng ti cht lng ca lung video c phn phi ti thu bao IPTV, n cng quyt nh cu trc mng v phc tp c yu cu h tr cc dch v IPTV. Cu trc mt mng IPTV gm c hai phn l mng truy cp bng rng v mng tp trung. Cc loi mng m rng khc bao gm cc h thng cp, in thoi cp ng, mng khng dy v v tinh c th c s dng phn phi cc dch v mng IPTV tin tin.

2.1. Cc loi mng truy cp bng rng Cc nh cung cp khc nhau la chn cc h thng phn phi ty thuc vo iu kin ti nguyn mng v nhu cu thc t. C bn loi mng truy cp (c dy dn) bng rng khc nhau c kh nng cung cp cc yu cu v bng thng ca dch v IPTV l:

Mng truy cp cp quang Mng DSL

Mng cp truyn hnh Mng Internet2.2. IPTV phn phi trn mng truy cp cp quangi vi IPTV th yu cu v bng thng ln nhng chi ph hot ng phi thp v trnh c cc can nhiu. Do , ngi ta quan tm ti vic s dng mng cp quang ang c sn trin khai cc dch v IPTV. Cc lin kt cp quang cung cp cho khch hng u cui mt kt ni chuyn dng tt nht thun tin cho vic tip nhn ni dung IPTV. Cc cng ngh v sn xut si quang gn y cho kh nng bng thng ln hn, t c th thc thi mt trong cc cu trc mng sau: Cp quang ti khu vc vn phng (FTTRO - Fiber to the reginal office ): Si quang t trung tm d liu IPTV ti khu vc vn phng mt cch gn nht c lp t bi cc cng ty vin thng hoc cng ty cp. Sau si cp ng s c s dng truyn tn hiu ti ngi dng u cui IPTV trong khu vc vn phng . Cp quang ti vng ln cn (FTTN - Fiber to the neighborhood): Nh ta bit si quang c tp trung ti cc node, FTTN i hi thit lp si quang t trung tm d liu IPTV ti b chia vng ln cn. y l v tr node c khong cch nh hn 1,5Km tnh t nh thu bao. Vic trin khai FTTN cho php ngi dng nhn mt gi cc dch v tr tin bao gm truyn hnh IPTV, truyn hnh cht lng cao v video theo yu cu. Cp quang ti l ng (FTTC - Fiber to the curd ): Si quang c lp t t trung tm d liu IPTV ti cc t cp c t ti l ng. T mt si dy cp ng hoc cp ng trc c s dng ni t u cui cp quang trong t cp ti v tr thit b IPTV ca nh thu bao.

Cp quang ti nh khch hng (FTTH - Fiber to the home): Vi si quang ti nh khch hng, ton b cc nh tuyn t trung tm d liu IPTV ti nh khch hng u c kt ni bi si quang ny. FTTH da trn mng quang c kh nng phn phi dung lng d liu cao ti ngi s dng trong h thng. FTTH l h thng thng tin song knh v h tr tnh nng tng tc ca cc dch v IPTV.

Vic phn phi nhng cu trc mng ny thng c trin khai bng hai loi mng khc nhau mt cht l mng quang th ng v mng quang tch cc.

2.2.1. Mng quang th ng

Mng quang th ng PON (Passive Optical Network) l cng ngh mng kt ni im - a im. Mng s dng cc bc sng khc nhau truyn d liu t trung tm d liu IPTV ti cc im ch m khng c cc thnh phn in. Mng quang th ng c xy dng da trn cc mng FTTx theo cc tiu chun quc t G.983 ca ITU l tiu chun ang c s dng hin nay.

Cp quang: Vi truyn dn bng cp quang th can nhiu thp v

bng thng cao. Theo tiu chun G.983 cho php mng PON truyn cc tn hiu nh sng c s ha vi khong cch ti a l 20Km m khng s dng b khuch i.

B chia quang: B chia quang c s dng chia tn hiu ti thnh nhng tn hiu n l m khng thay i trng thi ca tn hiu, khng bin i quang - in hoc in - quang. B chia quang cng c s dng kt hp nhiu tn hiu quang thnh mt tn hiu quang n. B chia quang cho php 32 h gia nh chia s bng thng ca mng FFTx.

Cp quang v b chia quang l cc thit b th ng, vic s dng cc thit b th ng truyn dn cc bc sng qua mng m khng cn cung cp ngun t xa gim chi ph vn hnh v bo dng.

Mng PON theo tiu chun G.983 bao gm mt kt cui ng quang OLT (Optical Line Termination) c t ti trung tm d liu IPTV v mt s cc kt cui mng quang ONT (Optical Network Termination) c lp t ti thit b u cui ngi dng.

Mc ch chnh ca ONT l cung cp cho cc thu bao IPTV mt giao din vi mng PON. N nhn lung tn hiu dng nh sng, gim st a ch c gn trong cc gi tin v chuyn i thnh tn cc tn hiu in v chuyn

i d liu thnh tn hiu quang truyn trn mng PON. Kt cui ng quang OLT bao gm cp quang v cc b chia quang nh tuyn lu lng mng ti cc kt cui mng quang ONT.

Hnh 2.1 Mng IPTV FTTH s dng cng ngh PON Hnh 2.1 miu t cu trc mng PON c bn c xy dng h tr phn phi cc dch v IPTV v Internet tc cao cho su h gia nh khc nhau. Mng PON trn hnh 2.1 cng m t 3 loi bc sng truyn dn khc nhau. Bc sng u tin c s dng mang lu lng Internet tc cao. Bc sng th hai c ch nh mang cc dch v IPTV v bc sng th ba c th c s dng mang lu lng tng tc t nh thu bao tr li nh cung cp dch v. Trn hnh 2.1 cng m t thit b ghp knh theo bc sng WDM, WDM c lp t ti trung tm d liu IPTV v bn trong kt cui OLT cho php mng PON h tr truyn dn nhiu knh song song hoc nhiu bc sng trn mt si quang. Nh vy, s to mt s knh quang o trn mt si quang n. Trong WDM, dung lng ca mng c tng ln bng vic gn bc sng bt u t ngun quang n cc bc sng ring bit. C 3 cng ngh mng PON l BPON, EPON v GPON h tr c truyn hnh v tuyn truyn thng v IPTV.

2.2.1.1. BPON

BPON (Broadband Passive Optical Network) mng th ng bng rng.

BPONsdngchuynmchmodetruyndnbtngbATM

(Asynchronnuos Transfer Mode) nh l giao thc vn chuyn. Cc mng da trn nn ATM hu ht u phn phi cc ng dng d liu, thoi v video tc cao. Chuyn mch ATM chia tt c thng tin truyn i thnh cc block nh gi l cc cell, v th n l cng ngh c tc rt cao. Cc cell c c nh kch thc, mi cell c 5 byte header v trng thng tin cha 48 byte d liu. Trng thng tin ca cell ATM mang ni dung IPTV, ngc li header cha thng tin thch hp thc hin chc nng l giao thc ATM.

ATM c phn loi nh l giao thc nh hng kt ni, cc kt ni gia u thu v u pht c thit lp trc truyn d liu video IP trn mng. Kh nng gi trc bng thng cho cc ng dng nhy vi tr l mt c tnh khc ca mng ATM. y l c tnh thng c s dng phn phi cc dch v IPTV. Vic phn phi cc knh ring bit cho cc dch v khc nhau gip loi b c can nhiu.

2.2.1.2. EPON

Mng th ng EPON(Ethernet PON) l mng PON s dng Ethernet lm c ch truyn dn. Cc tc h tr ph thuc vo khong cch gia OLT v ONT. Lu rng cc mng EPON ch h tr lu lng mng Ethernet. 2.2.1.3. GPON Mng quang th ng GPON (Gigabit PON) l h thng truy cp da trn tiu chun G.984 ca ITU-T. GPON v c bn l nng cp cho BPON, GPON h tr cho cc tc truyn dn hng xung cao hn, c th l 2,5Gbits hng xung v 1,5 Gbits hng ln, y l cc tc t c cho khong cch ln ti 20 km. Ngoi ra GPON cn h tr cc giao thc nh Ethernet, ATM v SONET, v cc c tnh bo an c ci tin.Bng 2.1. Sosnh cc cng ngh mng PON: BPON, EPON v EPONPON

Tiu chun ITU-T

Tc

Giao thc truyn dn

BPON

G.893

Up: 155 Mbps Down: 622 Mbps

Ch yu l ATM v IP trn Ethernet cng c s dng

GPON

G.894

Up: 1,5 GbpsDown:2,5GbpsEthernet v SONET

EPON

P802.3ah

Up: 1,25Gbps

Down: 1,25Gbps

Gigabit Ethernet

2.2.2. Mng quang tch cc Mng quang tch cc AON (Active optical network) s dng cc thnh phn in gia trung tm d liu IPTV v u cui ngi dng. Trong thc t, cu trc mng AON s dng cc chuyn mch Ethernet t ti v tr gia trung tm d liu IPTV v im kt cui ca mng cp quang.2.3. IPTV phn phi trn mng ADSL Bng thng l mt vn quan trng trong vic phn phi cc dch v IPTV th h mi. Mt s mng bng rng da trn DSL hin c c k tha t cc chun DSL. Ch rng DSL l cng ngh cho php cc nh cung cp vin thng phn phi cc dch v bng thng ln trn si dy cp ng ang dng ch truyn thoi. N lm bin i h tng mng cp in thoi ang tn ti gia tng i ni ht v in thoi nh khch hng thnh ng dy s tc cao. Trong mt s trng hp n khng th gi tn hiu truyn hnh cht lng chun trn mng truy cp DSL. Vic tng qu trnh thc thi c yu cu cho IPTV c th t c bng cch trin khai cc cng ngh DSL nh ADSL, ADSL2+ v VDSL.

2.3.1. ADSL

ng dy thu bao k thut s bt i xng ADSL l k thut trong h xDSL c s dng rng ri nht hin nay trn cc mng vin thng th gii. ADSL l cng ngh kt ni im - im, n cho php cc nh cung cp vin thng phn phi cc dch v bng thng rng trn ng dy cp ng in thoi ang tn ti.

Bng vic s dng cc k thut c trng, ADSL cho php tc downstream l 8 Mbps v tc upstream l 1,5 Mbps. Bi vy, mt kt ni ADSL ch cho ng thi hai knh truyn hnh qung b theo chun MPEG- 2 v mt kt ni Internet tc cao. im tr ngi chnh ca ADSL l ph thuc vo khong cch tnh t trung tm d liu ca nh cung cp ti nh khch hng. Dch v ADSL gii hn khong cch trn l 18.000 ft hay 5,5 Km.

Cc thit b ADSL cung cp mt kt ni k thut s trn mng PSTN, tuy nhin tn hiu truyn l tn hiu tng t. Cc mch ADSL phi s dng tn hiu tng t v mng mch vng ni ht (local loop) khng c kh nng truyn cc tn hiu m ha dng s.

Hnh 2.2. IPTV trn mng ADSLCc thit b c s dng trin khai dch v IPTV trn mng ADSL nh trn hnh 2.2 bao gm:

Modem ADSL: Ti nh thu bao c mt b thu pht ADSL hoc modem. Modem thng kt ni bng cng USB hoc giao tip Ethernet t mng gia nh hoc PC ti ng line DSL. a s modem hin ny u c tch hp chc nng nh tuyn h tr cc dch v d liu v truy cp Internet tc cao.

B lc POTS: Ngi dng c kt ni vi Internet bng kt ni bng thng rng ADSL s s dng mt thit b gi l b lc POTS lc tn hiu d liu t cc tn hiu thoi. B lc s lc tn hiu ti thnh tn hiu tn s thp a ti in thoi v tn s cao a ti mng gia nh. DSLAM - Digital Subscriber Line Access Multiplexer: b ghp knh truy cp ng dy thu bao s. Ti mi tng i khu vc (Regional Office) ca nh cung cp dch v IPTV, DSLAM nhn cc kt ni ca thu bao trn ng dy cp ng, tp hp chng li v kt ni tr li trung tm d liu IPTV bng cp quang tc cao da trn mng ng trc. DSLAM chu trch nhim trong vic phn phi ni dung IPTV t tng i khu vc ti cc thu bao IPTV. DSLAM c hai loi l DSLAM lp 2 v DSLAM nhn bit IP.

DSLAM lp 2: Hot ng ti lp 2 trong m hnh OSI v thc

hin cc chc nng nh chuyn mch lu lng gia Ethernet v ATM, chuyn tip cc lu lng mng ngc dng (up-stream) v ngn nga can nhiu gia cc thu bao IPTV. DSLAM h tr: H tr cc giao thc IP hot ng ti lp 3 trong m hnh OSI. Cc chc nng tin tin c tch hp trong cc DSLAM nhn bit

IP l ti to cc knh truyn hnh qung b v knh thc hin theo lnh.

Tc d liu: Tc ti a ca ADSL l 8 Mbps ch h tr s

dng tt cho hai knh truyn hnh cht lng cao v mt s lu lng Internet, tuy nhin, n s khng th p ng c cho cc nh cung cp IPTV khi phn phi cc chng trnh ln ti thu bao ca h.

Tnh tng tc: V cng ngh ADSL tc download thp hn tc

upload, do vy n s hn ch trong vic cung cp cc dch v ngang hng (peer-to-peer) yu cu bng thng download v upload bng nhau.

2.3.2. ADSL2

Cc chun ca h ADSL2 c a ra p ng cc yu cu v bng thng, h tr cho cc ng dng yu cu bng thng ln nh IPTV. C 3 loi khc nhau ca h ADSL2: ADSL2: ADSL2 bao gm mt s ci tin so vi chun ADSL gc l t tn khc, cc tc download cao hn v khong cch t tng i trung tm ti modem ca thu bao xa hn.

ADSL2+: ADSL2+ c xy dng trn ADSL2 v cho php cc nh cung cp dch v mng a ra cc tc ln ti 20 Mbps v hot ng tt trong khong 1,5 Km tnh t tng i trung tm ti modem nh thu bao.

ADSL(Reach): c gi l ADSL m rng hay vit tt l RE- ADSL2 (ADSL- Reach). RE-ADSL2 cho php cc nh cung cp dch v IPTV tng khong cch ln ti 6 Km tnh t tng i trung tm gn nht ti nh thu bao. N l cng ngh tt nht thc thi c trong gii hn v khong cch v tc trn cc si cp ng.

2.3.3. VDSL

ng dy thu bao s tc cao VDSL (Very high speed Digital Subscriber Line) da trn nhng nguyn l c bn nh cng ngh ADSL2+. N l cng ngh DSL mi nht v phc tp nht ti thi im ny, v n c pht trin khc phc cc khuyt im ca cc phin bn cng ngh truy cp ADSL trc y. N loi tr c hin tng tht c trai v h tr kh nng tc rt ln cho php cc nh cung cp dch v iu kin a ra cho cc thu bao IPTV rt nhiu dch v la chn bao gm c VoD v truyn hnh qung b nh dng HD. VDSL cng c thit k h tr cc truyn dn ca chuyn mch ATM v lu lng IP trn cp ng. Mt s thnh vin trong h gia nhVDSL nh sau:

VDSL1: N hot ng ti tc gii hn cao hn 55 Mbps cho knh hng xung v 15 Mbps cho hng ln. Tuy nhin n ch hot ng c trong khong cch ngn.

VDSL2: L mt ci tin t VDSL1 v c nh ngha trong kin ngh G.993.2 ca ITU-T. N c th c chia nh thnh VDSL2 (Long Reach) v VDSL2 (Short Reach).

ADSL2 (Long Reach): VDSL vi cc ci tin v khong cch c th cung cp cho cc thu bao IPTV tc truy cp bng rng l 30 Mbps cch tng i trung tm t 1,2 - 1,5 km.

VDSL2 (Short Reach): Chun VDSL2 s dng k thut ghp knh cho php n hot ng tc cao gp 12 ln so vi chun ADSL, tc l 100 Mbps cho knh hng xung trong khong cch 350 m. Mc d tc knh hng ln khng t c 100 Mbps, nhng cc tc vt tri hn so vi cc tc knh hng ln ca ADSL2+.

Cc c tnh mi ca VDSL2 nh ci thin cht lng dch v QoS v ci tin k thut m ha tt c u thch hp phn phi cc ng dng triple- play. C hai phng thc chnh c cc nh cung cp dch v IPTV s dng tch hp VDSL2 vo h tng mng ang c ca h. Phng thc th nht l thm cc thit b VDSL2 mi ti cc tng i khu vc v cho php DSLAM chy song song vi h thng DSLAM ADSL ang c. Phng thc th hai l t thit b VDSL2 gn thu bao IPTV.Bng 2.2: So snh cc cng ngh DSLCng ngh DSLDownsteam(Mbps)Uptream(Mbps)Khong cch (km)Cc dch v c h tr

ADSL815.5 kmMt knh video SD nn MPEG-2, truy cp Internet tc cao v cc dch v VoIp.

ADSL21216.5 kmHai knh video SD nn MPEG-2, hoc mt knh HD, truy cp Iternet tc d cao v cc dch v VoIP

ADSL+2516 kmNm knh video SD MPEG-2 hoc hai knh HD MPEG-4, truy cp Internet tc cao v cc dch v VoIP.

ADSL-Reach2516 kmNm knh video SD MPEG-2 hoc hai knh HD MPEG-4, truy cp Internet tc cao v cc dch v VoIP.

VDSL15515Vi trm mtMi hai knh video SD MPEG-2 hoc nm knh HD MPEG-4, truy cp Internet tc cao v cc dch v VoIP.

VDSL2(Long Reach)30301.2- 1.5 kmBy knh video SD MPEG-2 hoc mi knh HD MPEG-4, truy cp Internet tc cao v cc dch v VoIP.

VDSL2 ( Short Reach)100100350 kmMi hai knh video SD MPEG-2 hoc mi knh HD MPEG-4, truy cp Internet tc cao v cc dch v VoIP.

2.4. IPTV PHN PHI TRN MNG TRUYN HNH CP2.4.1. Tng quan v k thut HFC

Mng HFC (hybrid fiber/coax) l mng kt hp cp quang v cp ng trc, s dng ng thi cp quang vi cp ng trc truyn v phn phi tn hiu. Vic truyn tn hiu t trung tm n cc node quang l cp quang, cn t cc node quang n thu bao l cp ng trc. Cc mng xy dng da trn k thut HFC c mt s c tnh thun li chuyn giao cho cc dch v th h mi nh sau:

Mng HFC c kh nng truyn dn ng thi c tn hiu s v tn hiu tng t. y l c tnh rt quan trng cho cc nh khai thc mng.

Mng HFC c th chung ha gia vic tng dung lng v cc yu cu tin cy ca mt h thng IPTV. c im tng c dung lng ca h thng HFC cho php cc nh khai thc mng trin khai thm cc dch v m khng

cn phi thay i ton b cu trc mng.

c tnh vt l ca cp ng trc v cp quang h tr mng hot ng tc vi Gbps.

Hnh 2.3. Mng HFC end-to-endHnh 2.3 ta thy cu trc ca mng HFC gm c ng trc chnh l cp quang kt ni theo cc node quang ti mng cp ng trc. Node quang hot ng nh mt giao tip, n kt ni cc tn hiu upstream v downstream i ngang qua mng cp quang v cp ng trc. Phn mng cp ng trc ca mng HFC s dng topology cy-phn nhnh, cc thu bao truyn hnh kt ni ti mng HFC theo mt thit b c bit gi l b chia cp Tap. Tn hiu truyn hnh s c pht t trung tm d liu ti cc node quang. Node quang phn phi tn hiu thng qua cp ng trc, b khch i v b chia cp Tap ti khch hng.

2.4.2. IPTV phn phi trn mng truyn hnh cp

Do s cnh tranh v th trng kinh doanh truyn hnh thu ph t cc nh cung cp vin thng v nhng hiu qu ln v bng thng khi s dng k thut phn phi IP, dn ti cc nh khai thc mng truyn hnh cp phi hng ti s dng m hnh mng IP phn phi ni dung ti ngi dng.

Vic chuyn mt mng da trn tn s v tuyn RF(Radio Frequency) sang mng chuyn mch video s SDV (Switched Digital Video) trn nn IP, d bng cch no th vn cn phi lp t mt s thit b mi t cc router ti b gii m IP STB (Set-top box) v cc switch tc cao. Mt s u th ca vic trin khai sang mng chuyn mch SDV:

Mt s lng ln bng thng ca mng s c d tr bi v nh khai thc ch nhn c yu cu pht mt knh truyn hnh n l ti b gii m STB.

Bng thng d tha cho php cc nh khai thc mng cp truyn hnh c th phn phi cc dch v v ni dung IPTV ti thu bao ca h.

Nhng nh khai thc mng cp truyn hnh c th o c v gim st mt cch chnh xc ni dung xem ca mi thu bao. y l mt c tnh quan trng cho cc nh khai thc mun to thm doach thu bng qung co.

Hnh 2.4 M hnh trin khai cu trc mng IPTV cp quang kt hp IP v RF Hnh 2.4 m t mt cu trc mng IPTV cp c to thnh t s kt hp cc thit b ca cng ngh RF v cng ngh IP. Mt s thit b phn cng c m t trn hnh 2.4 bao gm: Switch hay Router GigE: GiE (Gigabit Ethernet) ni ln nh l mt giao thc vn chuyn c la chn kt ni cc thnh phn mng IP. GigE thng c s dng cho cc ng dng i hi dung lng cao, v d nh VoD. Router GigE tp hp lu lng IPTV v cung cp cc kt ni ti mng truy cp li. Mng truyn dn quang: Mng li cung cp con ng mng gia video server trong trung tm ni dung v cc b iu ch ti bin ca mng. Mng li c th l mng quang ng b SONET, mng ATM v mng ghp knh phn chia theo mt bc sng DWDM.

B iu ch bin: Cc b iu ch c t ti cc tng i khu vc nhn ni dung IPTV t mng li, chuyn i ni dung t cc gi IP sang RF v phn phi trn mng HFC ti b gii m STB.

Trong m hnh trn tt c ni dung u c iu ch thnh ccs sng mang RF v c bin dch thnh RF bng rng ng ra, thng nm trong di t 50 cho ti 860 MHz. Mt s h thng hot ng vi tn s ln ti 1 GHz, vi cc tn s cao thng c dnh ring cho cc dch v thoi v d liu. T trung tm d liu ca nh cung cp, mt ng trung k ln c s dng phn phi tn hiu bng rng ti cc Hub phn phi. T Hub phn phi, tn hiu bng thng rng c gi ti mng truyn dn quang, thng qua mng HFC, cc tn hiu bng rng c gi ti cc b STB trong nh khch hng.2.5. IPTV phn phi trn mng internet Li dng tc bng thng rng kt hp vi cc tin b trong trong k thut nn d liu v c nhiu chng trnh la chn hn cho php khch hng xem truyn hnh qung b v ni dung video theo yu cu, l l do ti sao s lng khch hng s dng Internet tng ln. IPTV trin khai trn mng Internet c th l mt trong cc dng ng dng sau.

2.5.1. Cc knh truyn hnh Internet streaming

Vic phn phi cc knh truyn hnh trn Internet l mt ng dng rng ri ca IPTV, bao gm ni dung video c streaming t mt server ti cc thit b client c kh nng x l v hin th ni dung video. Cc knh truyn hnh Internet c streaming cng c th a vo in thoi di ng hoc b gii m STB. Ni dung cc knh truyn hnh Internet c streaming cng c th c phn phi theo thi gian thc v ngi xem c th xem li theo cch xem truyn thng. Qu trnh k thut streaming knh truyn hnh Internet thng bt u ti server streaming, ti ni dung video c ng vo trong cc gi IP, nn li v pht qua mng Internet ti PC client. PC c cc phn mm, thng l mt chng trnh tm duyt (browser), gii nn ni dung video v pht ra video cn sng.

Khong thi gian t lc chn knh truyn hnh ti lc xem c thng ngn v ph thuc tc kt ni c th c gia server v client. M hnh cu trc mng c s dng phn phi knh truyn hnh trn Internet nh trn hnh 2.5.

Hnh 2.5 Cu trc mng cc knh truyn hnh Internet. Vic trin khai tt c cc knh truyn hnh Internet s yu cu mt server streaming, server ny s h tr cc chc nng sau: Lu tr v khi phc ni dung video ngun. iu khin tc cc gi video IP c phn phi ti thit b ca ngi xem.

Thc hin chuyn tip v chuyn ngc cc lnh yu cu t ngi xem truyn hnh Internet.

Mt server streaming n lm vic tt khi phn phi s lng t cc knh truyn hnh ti mt s thu bao c gii hn. h tr cho vic phn phi nhiu knh ti hng trm hoc hng ngn thu bao IPTV, th cn phi trin khai mt s lng ln server streaming trn cc ng mng khc nhau.

Cng vic streaming ni dung video hu ht u cn phi bo mt v ni dung khng c lu tr trn thit b truy cp ca khch hng. V th, vic sao chp ni dung tri php cn phi c ngn chn. Mt li th khc ca IPTV l kh nng hot ng hiu qu trn cc kt ni c bng thng thp v ngi xem c kh nng bt u xem ni dung ti mi im trong lung IPTV.

2.5.2. Download Internet

Nh tn gi, IPTV cho php khch hng download v xem ni dung theo

yu cu. Hu ht cc dch v download Internet u phi tr tin hoc tr theo dung lng download, cc dch v bao gm tin tc ni b v bn tin thi tit, phim in nh, phim ni b v m nhc, ch dn gii tr v cc qung co c phn loi. Mt s v tr cng Internet trc tuyn gn y bt u tin hnh a ra cc th vin ni dung chng trnh IPTV c th download cho ngi s dng Internet. Trong hu ht cc trng hp, mi ngi u s dng PC xem cc chng trnh download, tuy nhin, mt s cng ty bt u cung cp thit b gii m STB cho nhng khch hng khng mun xem trn PC. Mt s c im ca cng ngh IPTV end-to-end da trn cc dch v download Internet: Cc giao thc mng: chun giao thc truyn tp tin FTP v giao thc truyn siu vn bn HTTP thng c s dng truyn ni dung IPTV t server ti client. Vic s dng cc giao thc trn gim thiu kh nng ni dung IPTV b ngn chn bi firewall.

Cng ngh server: chun phn mm Web server thng c s dng p ng cc yu cu v ni dung video.

Tc mng: thi gian download mt b phim trn Internet ph thuc vo tc ca kt ni bng rng v cht lng ni dung video. Cc b phim in nh nh dng SD v cc chng trnh download tng i nhanh so vi ni dung video dng HD.

Cc nhu cu v lu tr: c server v client u yu cu kh nng lu tr tin tin h tr x l cc tp tin IPTV ln. Mt s ng dng ca download Internet cho php cc thu bao IPTV ghi li mt bn copy ni dung video c download vo a DVD v xem bng u DVD.

2.5.3. Chia s video ngang hng

ng dng chia s video ngang hng (peer-to-peer) cho php nhiu user xem, chia s v to ni dung video trc truyn. Vic s dng ng dng chia s video peer-to-peer khng phc tp v n thng l download v ci t mt s phn mm chuyn dng. Khi phn mm hot ng c trn PC, ngi dng ch cn click vo cc link download mt file video. Khi tin trnh download bt u, phn mm ng dng chia s video peer-to-peer c thit lp cc kt ni v bt u ly ni dung video c yu cu t cc ngun khc nhau. Khi file video c download v ghi y vo cng th c th xem

ni dung.

2.6. Cc cng ngh cho mng li IPTV H tng mng IPTV i hi phi truyn ti c mt s lng ln ni dung video tc cao gia trung tm d liu IPTV v mng phn phi bng thng rng. Mt s chun truyn dn mng li c cc kh nng bo v cn thit m bo tin cy cao. Mi chun c mt s c tnh ring bit v tc truyn dn tn hiu v kh nng m rng. C ba loi cng ngh truyn dn mng li chnh c s dng lm h tng mng IPTV l ATM trn nn SONET/SDH, IP trn MPLS v Metro Ethernet.

Nh miu t trn hnh 2.6 cc cng nh mng li cung cp vic kt ni gia trung tm d liu IPTV v cc mng truy cp khc nhau.

Hnh 2.6 H tng mng li IPTV2.6.1. ATM v SONET/SDH

Nh bit, ATM c th h tr cc ng dng nh IPTV i hi bng thng cao v cc truyn dn c tr thp. ATM hot ng trn cc mng khc nhau bao gm c cp ng trc v cp xon i, tuy nhin n chy tc tt nht l trn cp quang. Lp vt l gi l mng quang ng b SONET (Synchronuos Optical Network) thng c s dng truyn ti cc cell ATM trn mng li.

SONET l giao thc cung cp truyn dn tc cao s dng cp quang. Thut ng SDH (Synchronous Digital Hierarchy) c a ra cho cng ngh truyn dn quang theo tiu chun Chu u. Tc tn hiu SONET c o bng cc chun sng mang quang OC (Optical Carrier). Bng 2.3 l cc tc truyn dn ang s dng gi l cp OC.

Bng 2.3 Cc chun OC SONETCp OCTc truyn dn d liu

OC-1 (tc c s)51,84 Mbps

OC-3155,52 Mbps

OC-12622,08 Mbps

OC-241,224 Gbps

OC-482,488 Gbps

OC-19210 Gbps

OC-25613,271 Gbps

OC-76840 Gbps

SONET s dng ghp knh phn chia theo thi gian TDM ( Time Division Multiplexing) truyn nhiu lung cng mt lc. Vi TDM, mng SONET nh r bng thng cho v tr khe thi gian c th trn di tn s. Vic gn trc cc khe thi gian nh vy s hot ng bt chp c d liu c truyn hay khng. Thit b SONET nhn mt s lung bit v kt hp thnh mt lung n, cc tc c kt hp thnh mt tc chung. V d, bn lung lu lng IPTV c tc 1 Gbps s c kt hp thnh lung 4Gbps sau c chuyn tip ln mng cp quang.2.6.2. IP v MPLS Mt s ln cc cng ty vin thng bt u trin khai giao thc Internet IP trn mng li ca h. Mc d IP nguyn bn khng bao gi c thit k vi cc c tnh nh QoS hoc kh nng phn bit lu lng, giao thc lm vic tt nht khi n kt hp vi mt cng ngh gi l chuyn mch nhn a giao thc MPLS (Multiprotocol Label Switching). MPLS cho php mng h tr vic phn phi c hiu qu cc dnglu lng video khc nhau trn mt nn mng chung.

MPLS c thit k v xy dng bng vic s dng cc router chuyn

mch nhn LSR (Label Switch Router) tin tin. Cc router ny chu trch nhim thit lp cc tuyn kt ni c nh hng ti cc ch ring bit trn mng IPTV. Cc tuyn o ny c gi l cc tuyn chuyn mch nhn LSP (Label Switched Path) v c cu hnh vi y ti nguyn chc chn truyn dn tri chy lu lng IPTV thng qua mng MPLS. Vic s dng LSP lm n gin ha v tng tc nh tuyn cc gi thng qua mng v vic gi gi kim tra ch xut hin ti cc li vo ca mng v khng yu cu ti mi router hop.

Chc nng chnh khc ca LSR l xc nh cc kiu lu lng mng. y l iu t c bng vic thm MPLS header vo phn u ca mi gi tin IPTV. Cc thnh phn ca MPLS header c gii thch trong bng 2.4.Bng 2.4 nh dng MPLS header

Tn trng bit di trng bit (bit)Chc nng

Nhn20Chc cc chi tit ring bit ca hop tip theo cho mi gi IPTV

Cc bit d tr3c d tr cho user khc.

Stacking bit1Mt header c th cha mt hoc nhiu nhn. Mt khi stacking bit c thit lp, LSR s nhn dng c nhn sau cng trong gi.

Thi gian sng TTL8y l gi tr c copy t trng TTL trong IP header

Hnh 2.7 Topology mng li MPLSHnh 2.7 miu t header c thm vo LSR li vo v c g b bi LSR li ra. Li ch khc ca mng MPLS l h tr cc cp phc hi nhanh khi mng xut hin li.

2.6.3. Metro Ethernet

Mt cng ngh khc c th c trin khai trong mng li l Metro Ethernet. Mt lin minh ca cc nh cung cp dch v, cung cp thit b v cc cng ty v mng ni ting c thnh lp vi tn gi l MEF (Metro Ethernet Forum). MEF chu trch nhim thit lp cc chi tit k thut tch hp cc cng ngh Ethernet vo mng backbone dung lng cao v cc mng li. Ngoi vic pht trin cc chi tit k thut, MEF cn chng nhn thit b Ethernet s dng trong h tng mng ca cc nh cung cp dch v. Cc c im k thut v hot ng ca cc mng li da trn Metro Ethernet bao gm:

Cc thit b khc nhau phi thch hp c trng v cng ngh mng li, l kh nng phc hi nhanh, hiu sut thc thi cao v nng m rng.

Mt s thnh phn mng Metro Ethernet hin i c th hot ng ti tc ln ti 100 Gbps vi khong cch xa. N cung cp cho cc nh cung cp dch v mt nn tng mng l tng c kh nng phn phi cc dch v gi tr gia tng mi nh IPTV cho khch hng khong cch xa tnh t tng i khu vc. N thc thi c ch hi phc tinh vi cc li xy ra trn mng, do m bo cc dch v nh IPTV khng b nh hng do t qung.. Cc cng ngh Metro Ethernet h tr s dng vic kt ni cc mch o c nh hng, iu cho php cc nh cung cp dch v IPTV bo m vic phn phi ni dung video cht lng cao bn trong mng li. Cc lin kt chuyn dng ny c gi l cc kt ni o Ethernet EVC (Ethernet Virtual Connection). Hnh 2.8 trnh by cch s dng 4 EVC cung cp kt ni gia trung tm d liu IPTV v mt s tng i khu vc.

Hnh 2.8. S dng cc ECV kt ni IPTV qua li mngCHNG 3: QUN L MNG IPTV

Vic phn phi dch v truyn hnh trn mng IP tr thnh cc thch

thc v mt cng ngh v thng mi cho cc nh cung cp dch v IPTV. Mt trong nhng thch thc xut hin u tin trong hot ng ca mng IPTV hng ngy, l nh cung cp dch v cn phi c nng lc qun l lu lng video v cc thnh phn h tng mng IP. Cc nh cung cp IPTV cn phi c mt h thng qun l mng NMS (Network Management System), l cc b phn gim st v nhn dng cc s c c th nh hng ti vic phn phi cc dch v truyn hnh ti khch hng. Mt thch thc khc i vi nh cung cp l vn ci t mt dch v IPTV kh phc tp v to ra cc p lc cho ti nguyn mng ca nh cung cp dch v. V th, cn phi lp danh sch v chuyn mn ha cc bc ci t.

Ngoi vic qun l v cung cp cc dch v, cc nh khai thc mng IPTV cng cn phi bo m vic tip nhn dch v ca khch hng thun li hn so vi cc dch v c a ra t cc nh khai thc truyn hnh thu ph khc l truyn hnh cp v v tinh. trnh c cc thch thc trn, trong phn ny a ra mt s chc nng hot ng v k thut thnh cng trong vic trin khai IPTV.

3.1. H thng qun l mng IPTV Cc mng phn phi IPTV ngy nay to ra ngun thu nhp khng l cho cc nh khai thc. Tuy nhin vic qun l h thng IPTV end-to-end li l nhim v kh khn. Thnh thong, h thng c th mang n cc vn nh hng rt ln cho nh cung cp dch v IPTV. gim thiu ri ro v s c v mng, cc nh khai thc s dng h thng qun l mng NMS gim st cu trc mng IPTV end-to-end.

Cc chc nng c thc thi bi h thng qun l IPTV c th bao gm:Quan st mng 24/7: Mt h thng qun l mng NMS bao gm cc bn hin th thng tin cc tnh trng ca mt s thnh phn mng nh:

Cc thit b v server trung tm d liu IPTV. Cc thit b mng li IP. Cc thit b mng truy cp. Thit b khch hng IPTV. Cc mng gia nh.Ti u ha mng: NMS gip qu trnh ti u ha ti nguyn mng, h tr tng kh nng tch hp cc dch v da trn nn mng IP.

H tr nhn vin k thut: NMS tp hp cc bn tin li t cc thnh phn h thng IPTV end-to-end h tr nhn vin k thut nhn bit nhanh v gii quyt cc s c c th xy ra hng ngy trn mng IPTV.

Bo co: NMS tp hp cc trng thi ca cc thnh phn c bn ca mng thnh mt bo co h thng cho php ngi qun l mng IPTV:

Theo di v nh gi cc on t qung ca dch v IPTV. Kim tra sc khe ca cc thnh phn mng. Nhn dng cc vn tim tng trn mng thng qua phn tch chiu hng d liu. Ghi nhn vic s dng mng trong cc giai on c bit ch .Minh ha cc thnh phn bng th: Cc giao din trc gic c trng cung cp mt th hoc bn cc trng thi c th xy ra i vi cc thnh phn h tng mng IPTV end-to-end.Qun l cc li ca server trung tm: Cc server IPTV gi vai tr chin lc v cng quan trng trong mng truyn hnh bng rng. NMS h tr vic gim st server bng cch gi cc thng bo cnh bo v cc s c ti nhn vin k thut. Qun l cu hnh: NMS s lu tr cc mc thng tin cu hnh ca mi thit b c kt ni vo mng IPTV trong c s d liu. Cc dng thng tin ny c th l a ch IP hay cc phin bn Middleware ca mi thit b gii m STB. NMS cho php nhn vin k thut thay i cc tham s trn.Qun l bng thng: PTV l mt ng dng tn bng thng. NMS cho php cc nh cung cp dch v gi quyn iu khin cht ch vic s dng bng thng mng v ti u ha mng ca h cho cc ng dng trn nn IPTV.u tin ha lu ha lng: IPTV l ng dng nhy vi tr. ci thin cht lng dch v c phn phi ti user u cui, NMS cho php cc nh cung cp dch v u tin ha ni dung video trn cc ng dng khng nhy vi tr nh ng dng tm kim trn Internet v lu lng cc ng dng ngang hng.Qun l cc nht k mng: y l chc nng chu trch nhim ghi v lu tr nht k ca cc s kin xut hin trong thi gian hot ng ca mng IPTV. Thng tin nht k c lu tr gia cc NMS khc nhau, bao gm: Cc chi tit login v logout ca cc user IPTV. Cc chi tit thay i cu hnh ca h thng v thit b IPTVCD. Cc chi tit hot ng ca thit b mng.

Cc thch thc cho nhng ngi qun l h thng IPTV kt hp vi d liu t cc NMS khc nhau thu c mt ci nhn tng th chnh xc v qu trnh thc thi ca mng. Thm na, nhng ngi qun l cng cn kh nng h tr cc phn cng khc chy phn mm NMS ng gi ti trung tm d liu IPTV.3.1.1. S dng giao thc SNMP qun l mng IPTV

Giao thc qun l mng n gin SNMP l phng thc mnh m gim st v iu khin cc thit b trn c mng IP v non-IP. N l mt cu trc xc nh cc thng s cn qun l ca thit b. Ti cp c bn nht, SNMP l mt giao thc truyn tin xc nh cch thc thc thi ca h thng, d liu hot ng v cc lnh c tp hp t cc thit b ny. Hnh 3.1 trnh by cch b tr ca h thng SNMP c bn.Cc thnh phn ca h thng bao gm:

Network manager l b phn chu trch nhim v cc hot ng chnh xc ca mng.

Management console l thnh phn c trang b cho Network manager, n chu trch nhim tp hp thng tin v mng, hin th thng tin v thc hin cc lnh qun l mng.

Network management software chy trn manager console thc hin cc nhim v nh hin th cc trng thi mng, cc cnh bo ng nhp v gi cc lnh ti cc thit b mng. Phn mm ny s dng qun l SNMP thu thp thng tin t cc thit b mng khc nhau.

SNMP manager chu trch nhim v thng tin qun l cc thit b c qun l, gi cc bn ghi chp v cc trng thi hin ti ca mng trn c s d liu ch c gi l c s thng tin qun l MIM (Management information base).

SNMP c s dng truyn t thng tin ti cc thit b khc nhau hnh thnh mng, mt s SNMP c trnh by trn hnh 3.1.

Thit b 1 v 2 u c qun l trc tip do chng u c trang b mt SNMP agent v mt module c s d liu MIB ni b. SNMP agent chu trch nhim tp hp v lu tr trng thi thit b vo trong c s d liu MIB tr li cc lnh v cc yu cu cho d liu MIB t SNMP manager. SNMP agent cng c th pht ra cc yu cu c bit (gi l traps) ti SNMP manager trong cc trng hp c bit, v d nh cc yu cu khi ng li h thng ngay lp tc.

Thit b 3 v 4 khng c SNMP, v th c mt thit b c bit gi l proxy agent qun l chng. Proxy agent cha ng phn mm SNMP agent v mt module MIB bin dch d liu t cc thit b c gn vo. Proxy agent phi tp hp d liu t mi thit b bng mi cch c th, v d nh cccng serial trn thit b, gim st cc giao tip hoc cc phng thc khc.Hnh 3.1. H thng SNMP n gin Mt trong nhng li ch ln nht ca h thng SNMP l tp hp d liu v cc chc nng hin th c th c t ng ha. D liu t mi thit b c th c tp hp mt cch nh k phn tch mi hot ng c th xy ra. V d, SNMP thng c s dng tp hp d liu thc thi mng nh s lng gi b mt v hin th n cho Network manager. Hin tng nghn trn mt lin kt vt qu gii hn, lin kt ny c th thay i mu sc trn mn hnh Management console v c th bt u nhp nhy. N s bo hiucho Network manager iu tra nguyn nhn ca vic tc nghn v thc hin mt s hot ng chnh xc hn, v d nh gi i nhn vin sa cha hoc cu hnh li mng gi cc gi theo mt tuyn khc. Trong mi trng IPTV cc dng d liu c tp hp t mng IPTV ri voba loi ring bit sau:

Cc cnh bo: Cc cnh bo s thng bo cho nhn vin k thut ti trung tm d liu IPTV v hot ng bt thng trn mng. Cc cnh bo c s dng bi b phn k thut nhn dng ngun dch v b mt. Tnh trng hin hnh: D liu cc tnh trng hin hnh ca mng c tp hp li trn c s thng thng xc nh cc thnh phn mng IPTV c hot ng hay khng.

Cc thng k: Cc thng k mng v d nh cc cp lu lng mng c tp hp li bi h thng qun l trn c s thng thng. Mng IP c th thc thi tt hoc xu. D liu thng k c tp hp bi h thng qun l, v nhn vin k thut s dng n ti u ha tin trnh thc thi mng IPTV. Mng c ti u ha ci thin tc phn phi cho dch v IPTV v VoD.

Cc ng dng v c s d liu c lu tr trn mt server v s dng cc kt ni theo th t, cc giao tip dnh ring, hoc giao tip Ethernet truyn thng tin vi cc thit b mng IPTV:

Cc server IPTV. Thit b x l video trung tm d liu IPTV. Thit b IPTVCD. Cc router IP. DSLAM. H thng kt cui modem cp CMTS (Cable Modem Termination

System)

Mi thit b c ti trc mt module phn mm agent qun l NMP, chc nng chnh ca agent qun l l cung cp thng tin v thit b thng tr c s thng tin qun l MIB. Thng tin trong ha cc dng NMS khc nhau c th s dng c n.

Hnh 3.2 Lin kt h thng qun l mng IPTV Hnh 3.2 m t thng tin gia server qun l SNMP v cc SNMP agent da trn mt s lnh. Mt trong cc lnh l get v get next c nhn t mng IPTV, SNMP agent thc hin lnh c yu cu v gi tr li thng tin c yu cu. Thm vo thng tin yu cu tp hp v tr li, phn mm SNMP agent cng chu trch nhim gi cc cnh bo ngoi cc lnh c bit nhn t SNMP manager. Cc cnh bo s dng cc trap, mt SNMP agent c th thng bo cc s kin hoc cc li xut hin ti cc router, cho php cc nh qun l IPTV c th qun l cc thit b mng.

3.1.2. Qun l thit b bng trnh duyt web

Qun l thit b bng trnh duyt web cho php mt thit b mng vn c qun l t v tr khc thng qua s dng chun trnh duyt web. Thng tin v thit b c hin th trong ca s chng trnh tm duyt, v cc sa i cho hot ng ca thit b hay cu hnh c th c thit lp thng qua cc giao din ngi dng chun.

Mt s thit b s dng cc giao din IP cho hot ng chun ca n,

u tin l chc nng web server. y l server cho php truy cp web t xa thng tin vi b x l ca thit b cho mt s chc nng. Mt trong rt nhiu chc nng c thc thi trn web server l qun l thit b. Hnh 3.3 m t cc chc nng lm vic cng vi nhau.

Hnh 3.3 Cu trc qun l da trn trnh duyt web Trong hnh 3.3 thit b pha bn tay phi l mt thit b mng, c th l b m ho video MPEG vi mt kt ni IP, l mt switch vi port IP qun l hoc mt s thit b khc. Phn mm bn trong thit b thc hin chc nng web server, gim st port 80 t pha ti ca giao tip IP v x l cc yu cu ca giao thc HTTP. Cc yu cu ny c th n t mt s user khc nhau vi cc quyn truy cp khc nhau. p ng cc yu cu ny, server s cung cp cc trang web c thit k theo yu cu cho php user xem thng tin quan trng v thit b.

V d trong hnh 3.3 c ba lp truy cp c cung cp: nhn vin qun l mng, nhn vin bo dng v user c xc thc. Nhn vin qun l mng c ton quyn truy cp theo di mi mt ca thnh phn mng v c th sa i cu hnh ca thit b. Nhn vin bo dng c th quan st tt c cc trng thi v cu hnh ca thit b nhng khng th thay i cu hnh. User c xc thc c th b gii hn v quyn quan st cc trng thi ca thit b v khng c php thay i cu hnh. Cc lp truy cp khc nhau thng cthc hin chung trn phn mm web server thng qua vic s dng username v password c truyn dn trn cc kt ni m bo (HTTPS). Qun l da trn trnh duyt web c li cho vic qun l mt mng bao gm nhiu thit b phn tn trn phm vi rng trong thc t khi mng chia s phc tp.3.1. Qun l ci t Do s phc tp v vic la chn cc sn phm c th c trn mng, vic ci t, qun l cc s c ca dch v v mt s l do trc tip ca kt cui dch v c th l thch thc c bit v x l tn km cho cc nh khai thc mng trn ton cu. Vic ci t mng IPTV c th bao gm rt nhiu cng vic khc nhau, trong phn ny trnh by mt s ci t chung nh sau:

Phn phi a ch: Trong thc t, cc ngun video c c nh cc a ch IP, v th cc thit b IPTVCD c th xc nh chng. Vic phn phi a ch IP c ni r hn trong phn tip theo.

Ci t ngun video: y l cng vic thc hin sm nht trong tin trnh ci t v th cc thit b c th c kim tra vi video thc khi chng c ci t. Cc ngun multicast thng cn bng thng thp hn so vi cc ngun unicast gi bn sao lung video ti mi thit b ngi xem. Ci t cc phn mm client: Hu ht cc phn mm media player mt ph u t ci t, v hu ht cc PC c kh nng ci bng tay cc chng trnh ny.

Ci t cc phn cng client: Khi cc b gii m IP-STB hoc cc thit b client c ci t, mt s nh cung cp dch v quyt nh a nhn vin k thut ti nh khc hng. iu ny cho php cc cng vic kim tra mng c thc hin y v cc h tr khc c ci t chnh xc.

Cu hnh mutlicast: Nu phng thc multicast c s dng trong IPTV, mt phn ca tin trnh ci t phi kim tra li tt c cc thit b

mng c kh nng to lung multicast. Tin trnh ny c th yu cu phn mm hoc cc chng trnh nng cp phn cng trong cc thit b mng, v d nh cc router. Cu hnh h tng qun l mng: Mt ci tin ln ca cc mng IPTV trn nn IP l cc mng vt l ging nhau c th c s

dng gi v nhn cc lnh qun l mng v truyn dn video, vi iu kin l c cung cp kh nng thng tin hai chiu (two-way).

Qun l vic di di v lp rp thit b: Mi ln cc thit b c di di hoc lp t li th cn phi cu hnh li h thng m bo khng c cc thng bo li v v tr vt l ca thit b.

3.2. Gim st thc thi v kim tra mng Gim st thc thi l quan st qu trnh vn hnh ca mng c c cc hot ng chnh xc. Tt c cc loi vn hnh u c th c gim st, t vic m cc li trn mt lin kt d liu cho ti vic theo di s lng ngi xem ni dung cng mt lc. Nu tin trnh thc thi khng t c cc yu cu quy nh trc th cc cnh bo s c pht ra phc v cho vic d on cc li sm nht c th.

Thng thng, vic gim st l trch nhim c thc hin bi nhiu thnh phn. u tin cc thit b s thu thp s liu v cc hot ng ca chnh bn thn mi thit b, v h thng qun l tp trung s bin dch cc d liu ny phn tch nh k. Trong mt s h thng, d liu c lu tr trn mi thit b v ch c s dng khi nhn vin k thut h thng quyt nh nhn n. Sau , b x l tp trung s phn tch d liu liu ti v thng bo cho nhn vin k thut khi thit b li. Mt s dng d liu c thu thp v phn tch bi h thng gim st thc thi nh sau:

Li bit: Mt s loi mng bao gm mt byte kim tra tng hoc kim tra chn l s ch ra cc bit hoc cc gi tin b thay i.

Li bit: Mt s loi mng bao gm mt byte kim tra tng hoc kim tra chn l s ch ra cc bit hoc cc gi tin b thay i.

Cc gi mt: Trong trng hp nghn mng, mt s thit b s khng gi c ht s gi, v th lung tn hiu s b mt cc gi . Thng qua vic gim st s lng gi b mt ti cc v tr khc nhau trong mng, cc nh khai thc mng s xc nh c dung lng cn tng ln, s lng router cn xy dng thm cho dch v hoc cc lin kt cn phi c bo dng.

Cc trng thi ca thu bao: Tt c cc loi d liu thu thp v thu bao c phn tch xc nh xem c vn g xy ra vi cc kt ni t pha

thu bao hay khng, t sm pht cnh bo v cc s c trn mng. Cc hot ng ng nhp ca user : D liu ny c th ch ra cc

user ang gp s c khi truy cp h thng hoc user gian ln v quyn truy cp, v d nh c nhiu user ging nhau truy cp vo h thng ti nhiu v tr khc nhau trong cng mt thi im.

Gim st h thng bo an: Thng qua vic thu thp d liu v qu trnh thc thi ca h thng bo an, cc nh khai thc c th xc nh cc firewall ang lm vic chnh xc, cc ngun tn cng mng t bn trong hoc bn ngoi, cung cp cc cnh bo v virus. Thng tin ny cng c th c s dng sau khi mt l thng bo an c xc nh tm ra cch ngn nga cc s c bo an trong tng lai.

Vic gim st thc thi lm vic ngn nga cc s c mng do mt vi thit b c hin tng gim hiu sut thc thi trc khi chng ngng hot ng hon ton. H thng trung tm d liu IPTV c to nn bi nhiu thnh phn phc tp v ngy cng nhiu dch v hn, v th vn cc v mng phi c pht hin v gii quyt nhanh hn. tng ti a thi gian chy h thng v m bo cc dch v c phn phi ti khch hng vi cht lng cao nht, th vn gim st v kim tra cn c tin hnh trn c s h tng mng. Vic gim st cht ch mng IPTV s c mt s li ch sau:

Cho php cc nh qun l mng nhn ra cc kiu lu lng mng, t cho bit s t qung hoc s gim st cht lng hnh nh sp xy ra. Vic pht hin ra cc vn tim tng lm gim bt kh nng xy ra cc on t qung ln hoc gim st t ngt cht lng video. Sa cha ngay lp tc s t qung mng d l nh nht.

Mang n cho nhm k thut kh nng c tnh phm vi s c mng khi n xut hin. Cp nguy him ca s c s ra lnh cho cc ti nguyn no c s dng xc nh v tr s c. V d, nu s c gim st nh trong cht lng tn hiu video th chin lc sa cha s c s khc so vi cc li ca server VoD ti trung tm d liu IPTV.

m bo cc user IPTV xem c cht lng cao, c th tin hnh mt s kim tra cc thnh phn mng IPTV nh sau:Thit b truy cp: Thng tin hnh kim tra cc thnh phn phn cng v phn mm c ci t gn nht, cc user IPTV c th c xem vi cht lng nh mong i v ti u ha vic phn phi cc dch v IPTV a im v n im. Cc ni dung tin hnh kim tra bao gm:

Kim tra tc d liu di chuyn trong mng thit b truy cp thu bao.

nh gi cc li v cc vn thc thi xut hin do giao thc IP, cc lp ng gi v vn chuyn video ca m hnh thng tin IPTV.

Mng li IP: Thng tin hnh kim tra tt c phn mm v phn cng c s dng phn phi cc dch v IPTV. Cc thng s cu hnh mng c th lun thay i, khi c nh hng ti cc lung IPTV c phn phi. V th cc nh qun l mng phi tin hnh kim tra nh k cc cp thc thi lung thng tin khi c s thay i xut hin trn mng. Cc thay i c th xut pht t vic mng c thm mt switch hay c s thay i firmware ca cc thit b.

Thit b trung tm d liu IPTV: Cc thit b khc nhau c ci t ti trung tm d liu IPTV cn c kim tra y m bo n c kh nng phn phi nhiu dch v IPTV ti s lng ln thit b IPTVCD mt cch chc chn v hiu sut cao. K hoch kim tra cng cn thc hin thng xuyn trn ni dung cung cp bi cc nh cung cp ni dung m bo t c cc cp cht lng vi cc thng s tha thun.

Thit b IPTVCD: Kim tra cc thit b IPTVCD bit cc thit b IPTVCD no c s dng cung cp cho user truy cp cc dch v. Cc loi kim tra tin hnh trn thit b IPTVCD c th thay i theo cc knh c yu cu bi ngi xem, cc knh ny c iu khin t xa, l cc knh thc t nhn c m bo thi gian thay i knh khi s lng thu bao kt ni ti cc server IPTV ln.

3.4. Qun l v d phng Dch v IPTV c cc yu cu v kh dng v tin cy. ngn nga cc hin tng lm t qung vic cung cp dch v th cc thit b mng v thit b trung tm d liu IPTV cn c h tr vic thay th nhanh chng cc thit b gp s c. Thi gian cn thit thay th s ch l vi ms m bo s c khng nh hng ti dch v. Cc cp d phng ca phn cng v phn mm i khi c cc nh cung cp dng gim thiu nh hng ca vic t qung dch v ln cc thu bao IPTV.

Hnh 3.4 Thit k mng h tr d phngHnh 3.4 miu t thit k mng h tr mt cp d phng c ci tin ti trung tm d liu IPTV cng nh bn thn mng. Mng c miu t bao gm mt s c tnh d phng sau:

Topology mng ring i xng c s dng truyn ti lu lng IPTV ti li mng.

V th khi lin kt b t ti bt k ch no trong mng ring th lu lng IPTV s c nh tuyn i theo hng ngc li trong mng ring.

Cc thnh phn h tng mng c lp t song song hai thit b. Trong v d ny, VoD server, server streaming multicast IPTV v b m ha u c hai thit b.

Router phn phi d phng cng c lp t m bo router sn sng truyn ti nu mt trong hai thit b gp s c.

Mi b m ha c hai cng ra.

Mt s lin kt d phng cng c sn sng gia router phn phi v cc router bin phc v s lng ln user u cui.

Cc cp d phng c xy dng khi thit k mng IPTV s ph thuc vo loi dch v IPTV c trin khai trn mng. Cc h thng bo dng tinh vi thng c cc nh cung cp s dng theo di cc hot ng bo dng hng ngy v hng tun. Ngoi cc hot ng bo dng theo di, h thng ny cng duy tr cc chi tit d phng sn sng cho php cc nh qun l mng IPTV phn tch v ln k hoch bo dng trong tng lai.3.5. Qun l khng gian a ch IP Vic phn phi cc a ch IP s lun l vn vi cc mng c thit k truyn ti dch v. V d, trong mi trng triple-play n c th cu hnh cc IP subnet khc nhau cho mi dch v voice, truy cp Internet v IPTV. N cng c kh nng thit k mt lc a ch IP h tr vic chia s cc thit b h tng mng nh qun l DSN, OSS v cc DHCP server cho tt c cc dch v. Mt khi lc a ch IP c cu hnh trn cc thit b c chia s, th n c th chia IP subnet hoc pool a ch cho cc ti nguyn mng phn phi dch v triple-play. V d, VoD server v IP-STB ti nh thu bao u c cu hnh nh l mt phn ca subnet dch v IPTV. Vic phn phi a ch IP trong mng IPTV l trch nhim ca DHCP server.

DHCP l chc nng c yu cu trong mt s cng ty mng v cc nh cung cp dch v Internet ISP (Internet Service Provider). Vi DHCP, mt my tnh ch s dng duy nht mt a ch IP truy cp Internet. DHCP cng c tc dng khi ng dng trong mng IPTV. s dng DHCP, mi thit b IPTVCD phi tm DHCP server trong mng bng cch pht broadcast mt yu cu ti tt c cc thit b. Khi DHCP server nhn c yu cu, n s chn mt a ch IP ang sn sng c s dng v gi tr li thit b IPTVCD yu cu. DHCP cung cp cho cc nh qun l mng IPTV

mt s thun li sau:

Bng vic s dng DHCP, tt c cc chi tit cu hnh cn thit cho

IPTVCD c b tr trc m khng cn user c bit v cc chi tit

khng. Khng cn phi cu hnh cho mi thit b mt a ch IP c nh. DHCP tp trung ha vic qun l a ch IP.

Vic ci t DHCP server t ng phn phi cc a ch IP cho cc thit b trn mng IPTV thng khng phc tp. DHCP c th nh r mt dy a ch IP sn sng c dng cho tng vng ring bit. C th tch hp DHCP v OSS h tr vic cung cp cc dch v

IPTV mi.

3.6. X l cc s c IPTV Cc s c gp phi ca thu bao IPTV vi cc dch v thng c thng bo bng cch gi ti b phn dch v khch hng.Vic x l s c mng IPTV tng t nh x l s c cc ng dng trn nn IP khc. Trc ht, s c cn c c lp, v s ph thuc vo bn cht v phm vi ca s c. Tip theo s l sa cha s c, vic sa cha s c thng t c kt qu tt bng cch thay i cu hnh hoc thay th thnh phn b li trn mng. Hu ht cc li trn cc mng IPTV ri vo 5 vng sau:Mng: Cc li c th xut hin trong cc thnh phn khc nhau ca mng. Nhn vin k thut IPTV thng s dng b nh hi (sniffer) kho st d liu i qua mng cn hot ng. B phn tch giao thc thng c mt PC, mt card mng v mt ng dng phn tch cc s c trn mng. Vic phn tch mng trong thi gian thc gip pht hin v gii quyt cc li mng v cc s c nhanh hn.

Cc server backend: Cc phn mm server c bit thng c s dng x l cc s c xut hin trn server.Thit b IPTVCD: tin cy cao l iu c mong i t cc thit b IPTVCD nh b gii m STB v cc thit b gateway. V th cc nh cung cp dch v IPTV pht trin cc h thng tinh vi tp hp cc bn tin li t thit b IPTVCD v s dng thng tin x l cc s c c th xut hin trn dch v IPTV. Cc s c thng thng bao gm cc vn v b nh m, cc trc trc v phn cng v li phn mm. Khi vng s c c nhn bit giai on tip theo l gii quyt s c, c th bao gm cc hnh ng sau: Thay i cu hnh ci cho thit b IPTVCD. Thng bo qua in thoi cc s c xy ra cho ngi s dng v cung cp cc lnh gii quyt s c. Cng c th s dng e-mail b sung thng tin v cc lnh. Khi cc s c khng gii quyt c qua in thoi th nhn vin k thut bt buc phi ti nh khch hng. V cui cng khng gii quyt s c bng cc hnh ng trn ta nh

phi thay th thit b mi.Mng trong nh khch hng: Cc s c nh ng i dy trong nh b

hng, cp km cht lng, virus, ci t a ch IP khng ng v driver khng ph hp tt c u c th tc ng ti dch v IPTV. H thng qun l t xa kt hp vi in thoi hoc e-mail h tr thng c s dng x l cc s c xut hin trn mng trong nh khch hng.Nh cung cp ni dung bn ngoi: Vic tip nhn ni dung l nhng video c m ha km cht lng to nn cc s c v truyn dn. Khi s c c nhn bit nh cung cp th 3 ny cn c thng bo v x l s c.

3.7. Qun l quyn ni dung s Qun l quyn ni dung s DRM (Digital Right Management) l mt tp hp cc nh ngha v cc c ch c s dng iu khin truy cp ni dung thng qua vic mt m hoc cc phng php khc. DRM lun lun l mt yu cu s dng trong vic cung cp ni dung video thi gian gn y trn h thng phn phi IPTV cng nh h thng truyn hnh cp v truyn hnh v tinh. Cc chnh sch DRM c th rt cht ch hoc cng c th rt bung lng; quyn s hu ni dung xc nh cc chnh sch kim sot. Mt khi cc chnh sch ny c xc nh, trch nhim ca h thng DRM l lm cho cc chnh sch ny c hiu lc. Trn hnh 3.5 l m hnh khi n gin ca mt h

thng DRM.

Hnh 3.5: M hnh khi h thng DRMn gin.

Trong h thng DRM thc t cho h thng VoD, quyn s hu ni dung c hai nhim v. u tin, ni dung phi c phn phi ti mt server m bo, ni dung c th c truy cp da trn cc yu cu ca ngi xem. Th hai, cc quy nh cho ngi xem phi c nh r. V d, ngi xem tr mt gi ch c th xem ni dung ca mt lung, ngc li th c mt s ngi c th download ni dung v xem n trong mt khong thi gian no . H thng DRM lm cc quy nh c hiu lc i vi quyn s hu ni dung, n cn c cp nht nhng ngi tham gia vo v ri khi h thng. H thng DRM chu trch nhim m bo chc chn ngi xem tr tin cho ni dung m h yu cu. Ch rng, DRM cng c th c s dng cho ni dung min ph, bo v ni dung trnh vic sao chp v bn li khng c xc th3.8. Qun l cht lng dch v QoS Cht lng dch v QoS l tp hp cc ch tiu c trng cho yu cu ca tng loi lu lng c th trn mng bao gm: tr jitter, t l mt gi Cc ch tiu ny lin quan n lng bng thng dnh cho mng.

vic ng b tn hiu c th thc hin c mng buc phi c qun l cht ch v cht lng dch v. thc hinvic c qun l cht lng dch v cn thit phi c:

Chnh sch m bo cht lng dch v (QoS policy). Cc c ch m bo cht lng dch v ti cc nt mng: Cc thut ton xp hng (queuing), c ch nh hnh lu lng (traffic shapping), cc c ch ti u ha ng truyn, cc thut ton d on v trnh tc nghn Phng thc bo hiu QoS.

Hnh 3.6: Qun l cht lng dch v QoS.Chnh sch QoS c vch ra mong mun thc hin v qun l cht lng dch v theo k hoch c th v thng qua h thng bo hiu QoS ra

lnh cho cc c ch chp hnh ti cc nt mng thc hin nhim v .

3.8.1. kh dng ca mng

kh dng ca mng l mt n v o phn thi gian mng sn sng c s dng bi khch hng. Mt mng c gi l khng kh dng khi n khng th s dng cho cc lu lng khch hng, do mng mt cc kt ni hon ton hoc t l li cao qu mc. Cc kt ni mng mt hon ton xut hin khi cc kt ni khng c kh nng hot ng, l khi cp quang b t hoc mt ngun ti mt thit b no . Mt t l li cao qu mc thng c nh ngha l t l li 103 ngha l c mt bit li trong 1000 bit c pht i, n cng c th n n mt li trong gi.Trong thc t, kh dng ca mng c o bng t l phn trm ca tng s thi gian mng sn sng c s dng trn tng s thi gian o c. V d, mt nh cung cp cam kt t l kh dng ca mng l 99,99%, hay thi gian dch v khng kh dng l 52 pht trong mt nm. Tuy nhin, xt cho cng khong thi gian mng khng kh dng c th c tnh, v thc cht thi gian khng vi phm cam kt cp dch v SLA.3.8.2 Phn lp dch v

Phn lp dch v c s dng a ra cc dng d liu ca cc lp cp dch v khc nhau truy cp ti nguyn mng. Cc nh qun tr mng IPTV c th n nh cc lp dch v khc nhau vo cc loi ng dng khc nhau, ty thuc vo cp thc thi cn thit. Trong mi trng IPTV s c th t cc lung video phn phi cho thu bao, v d liu video cn ti ch mt cch mt m, lin tip. Trn mng truyn dn c nhiu loi lu lng, do t c mc ch trn mt phng thc c s dng l n nh phn lp dch v cho lu lng video. Khi , n ra lnh cho router hoc thit b mng khc a ra quyn u tin cho cc gi tin ny.

Trn hnh 3.6 trnh by ba hng i quyn u tin khc nhau; chng ta s gi ba quyn u tin ln lt l cao, trung bnh v thp. Cc hng i ny hot ng nh sau: cc gi tin mi i vo pha sau ca hng i v i cho n khi chng tin ln pha u ca hng i trc khi c pht i. Trong trng hp ny, tt c hng i ang ua tranh, nhng ch c mt u ra n, v th cn phi n nh cc quy lut hot ng: Ti mi thi im u ra sn sng c s dng, mt gi tin c chn t mt trong ba hng. Nu khng c gi tin no sn sng trong cc hng th gi tin rng (null) s c gi. Nu mt gi tin sn sng trong hng c quyn u tin cao th nc gi ngay lp tc. Nu khng c gi tin sn sng trong hng c quyn u tin cao v mt gi tin sn sng nm trong mt trong hai hng cn li (khng ng thi trong hai hng) th gi tin s c gi. Nu khng c gi tin no sn sng trong hng c quyn u tin v cc gi tin sn sng u nm trong c hai hng cn li, th cc gi tin s c gi theo t l 3 gi tin hng c quyn u tin trung bnh ti 1 gi trong hng c quyn u tin thp.

Qua v d ny chng ta c th thy ti sao mng c th khng gi lung video ln hoc cc gi tin s dng hng c quyn u tin cao v n s rt kh cho cc gi tin khc mun i qua. Vic gi video vi quyn u tin thp cng khng thch hp v s c cc gi tin s c hin th trong khi cc gi khc ang c x l. Quyn u tin trung bnh c th l la chn cho video, v hu ht lu lng nonvideo c to quyn u tin thp. Cc gi tin c quyn u tin thp c th tr hon, c gi bi cc router khc nhau, trong trng hp xu nht khi mng b nghn cp cao nht, b xa do khng dc phn phi. Vic cc gi tin b xa cng c th xut hin nu router s dng loi b ngu nhin gi cc hng khi b trn.

Hnh 3.7 V d s dng ba hng i c quyn u tin3.8.3. Cc cam kt cp dch v

Cc cam kt cp dch v SLA (Service-Level Agreement) l hp ng gia nh cung cp dch v v khch hng v cc chi tit cht lng dch v c cung cp. SLA c th bao gm cc c tnh v chc nng ca mt s loi dch v t thoi cho ti VoD. SLA c n gin ho bng mt bng k khai cc cam kt, bng k khai ny ghi r gi tr chi tit cc dch v vin thng phi a ra. Cc dch v trong bng k khai phi c a ra cho tt c khch hng. Bng k khai i khi cn bao gm cc cp dch v m nh cung cp a ra. Mt s nh ngha trong bng k khai SLA nh sau:

kh dng (%): T l thi gian dch v sn sng s dng, t l

ny trong SLA thng l 99% hoc ln hn. T l phn phi gi(%): T l gi c phn phi ti ch trn tng s gi gi i. Ch , t l ny c th c o trung bnh hng thng v da trn d liu mu, khng da trn tng s gi c gi i. Trong SLA t l ny l 99% hoc ln hn. T l mt gi(%): Ngc li vi t l phn phi gi, y l s gi b mt trn tng s gi gi i. Trong SLA t l ny l 1% hoc thp hn. tr mng (ms): y l ch s tn