Guide to Voice and Video over IP: For Fixed and Mobile Networks

277 Pages·2013·11.455 MB·English

by  Lingfen Sun, Is-Haka Mkwawa, Emmanuel Jammeh, Emmanuel Ifeachor (auth.)

Computer Communications and
Networks
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Lingfen Sun (cid:2) Is-Haka Mkwawa (cid:2)
Emmanuel Jammeh (cid:2) Emmanuel Ifeachor
Guide to Voice and
Video over IP
For Fixed and Mobile Networks
LingfenSun EmmanuelJammeh
SchoolofComputingandMathematics, SchoolofComputingandMathematics,
UniversityofPlymouth, UniversityofPlymouth,
Plymouth,UK Plymouth,UK
Is-HakaMkwawa EmmanuelIfeachor
SchoolofComputingandMathematics, SchoolofComputingandMathematics,
UniversityofPlymouth, UniversityofPlymouth,
Plymouth,UK Plymouth,UK
SeriesEditors
A.J.Sammes
CentreforForensicComputing
CranfieldUniversity
Shrivenhamcampus
Swindon,UK
ISSN1617-7975 ComputerCommunicationsandNetworks
ISBN978-1-4471-4904-0 ISBN978-1-4471-4905-7(eBook)
DOI10.1007/978-1-4471-4905-7
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Preface
Since the release of the first Internet Phone in 1995, Voice over Internet Protocol
(VoIP)hasgrownexponentially,fromalab-basedapplicationtotoday’sestablished
technology,withglobalpenetration,forreal-timecommunicationsforbusinessand
daily life. Many organisations are moving from the traditional PSTN networks to
modernVoIPsolutionsandareusingVoIPproductssuchasaudio/videoconferenc-
ing systems for their daily business operation. We depend on different VoIP tools
suchasSkype,GoogleTalkandMicrosoftLynctokeepcontactwithourbusiness
partners,colleagues,friendsandfamilymembers,virtuallyanytimeandfromany-
where.WenowenjoyfreeorlowcostVoIPaudioorevenhighqualityvideocalls
whichhavemadetheworldlikeasmallvillageforreal-timeaudio/videocommuni-
cations.VoIPtoolshavebeenincorporatedintoourmobiledevices,tablets,desktop
PCsandevenTVsetsandtheuseofVoIPtoolsisjustaneasyone-clicktask.
Behind the huge success and global penetration of VoIP, we have witnessed
great advances in the technologies that underpin VoIP such as speech/video sig-
nal processing and compression (e.g., from narrowband, wideband to fullband
speech/audiocompression),computernetworkingtechniquesandprotocols(forbet-
ter and more efficient transmission of multimedia services), and mobile/wireless
communications(e.g.,from2G,3Gto4Gbroadbandmobilecommunications).
This book aims to provide an understanding and a practical guide to some of
thefundamentaltechniques(includingtheirlatestdevelopments)whicharebehind
the success of VoIP. These include speech compression, video compression, me-
diatransportprotocols(RTP/RTCP),VoIPsignallingprotocols(SIP/SDP),QoSand
QoEforvoice/videocalls,NextGenerationNetworksbasedonIPMultimediaSub-
system (IMS) andmobileVoIP,togetherwithcase studies on how to builda VoIP
system based on Asterisk, how to assess and analyse VoIP quality, and how to set
up a mobile VoIP system based on Open IMS and Android mobile. We have pro-
vided many practical examples including real trace data to illustrate and explain
the concepts of relevant transport and signalling protocols. Exercises, illustrative
workedexamplesinthechaptersandend-of-chapterproblemswillalsohelpreaders
tochecktheirunderstandingofthetopicsandtostretchtheirknowledge.Step-by-
stepinstructionsareprovidedinthecasestudiestoenablereaderstobuildtheirown
open-sourcebasedVoIPsystemandtoassessvoice/videocallqualityaccordingly,
ortosetuptheirownmobileVoIPsystembasedonOpenIMSCoreandIMSDroid
withanAndroidmobile.Challengingquestionsaresetupinthecasestudiestohelp
themtothinkdeeperandtopracticemore.
v
vi Preface
This book has benefitted from the authors’ research activities in VoIP and re-
lated activities of over 10 years. In particular, it has benefitted from the recent in-
ternational collaborative projects, including the EU FP7 ADAMANTIUM project
(Grant agreement no. 214751), the EU FP7 GERYON project (Grant agreement
no. 284863) and the EU COST Action IC1003 European Network on Quality of
ExperienceinMultimediaSystemsandServices(QUALINET).Thebookhasalso
benefittedfromtheauthors’teachingexperienceindevelopinganddeliveringmod-
ules on “Voice and Video over IP” to undergraduate and postgraduate students at
PlymouthUniversityinthepastfouryears.Someofthecontentsofthebookwere
drawn from the lecture notes and some of the case studies materials from the lab
activities.
This book can be used as a textbook for final year undergraduate and first year
postgraduatecoursesincomputerscienceand/orelectronicengineering.Itcanalso
serveasareferencebookforengineersinindustryandforthoseinterestedinVoIP,
for example, those who wish to have a general understanding of VoIP as well as
thosewhowishtohaveanin-depthandpracticalunderstandingofkeyVoIPtech-
nologies.
Inthisbook,Dr.SunhascontributedtoChaps.1(Introduction),2(SpeechCom-
pression),3(VideoCompression),4(MediaTransport)and6(VoIPQoE);Dr.Mk-
wawahascontributedtoChaps.1(Introduction),5(SIPSignalling),7(IMSandMo-
bileVoIP),8(CaseStudy1),9(CaseStudy2)and10(CaseStudy3);Dr.Jammeh
has contributed to Chap. 3 (Video Compression) and Professor Ifeachor has con-
tributedtoChap.1(Introduction)andthebookediting.Duetothetimeconstraints
andthelimitationofourknowledge,someerrorsoromissionsmaybeinevitablein
thebook,wewelcomeanyfeedbacksandcommentsaboutthebook.
Finally, we would like to thank Simon Rees, our editor at Springer-Verlag for
his encouragement, patience, support and understanding in the past two years in
helpinguscompletethebook.Wewouldalsoliketoexpressourdeepestgratitude
to our family for their love,support and encouragementthroughoutthe process of
thisbook.
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 OverviewofVoIP . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 HowVoIPWorksandFactorsThatAffectQuality . . . . . . . . . 3
1.3 VoIPTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.1 Microsoft’sLync . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.2 Skype . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3.3 GoogleTalk . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.4 X-Lite . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.4 VoIPTrend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.5 VoIPProtocolStackandtheScopeoftheBook . . . . . . . . . . . 12
1.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2 SpeechCompression . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.2 SpeechCompressionBasics . . . . . . . . . . . . . . . . . . . . . 18
2.2.1 SpeechSignalDigitisation. . . . . . . . . . . . . . . . . . 18
2.2.2 SpeechWaveformandSpectrum . . . . . . . . . . . . . . 21
2.2.3 HowIsHumanSpeechProduced?. . . . . . . . . . . . . . 23
2.3 SpeechCompressionandCodingTechniques . . . . . . . . . . . . 25
2.3.1 WaveformCompressionCoding . . . . . . . . . . . . . . . 26
2.3.2 ParametricCompressionCoding . . . . . . . . . . . . . . 28
2.3.3 HybridCompressionCoding—Analysis-by-Synthesis . . . 31
2.3.4 NarrowbandtoFullbandSpeechAudioCompression . . . 35
2.4 StandardisedNarrowbandtoFullbandSpeech/AudioCodecs . . . 36
2.4.1 ITU-TG.711PCMandG.711.1PCM-WB . . . . . . . . . 36
2.4.2 ITU-TG.726ADPCM . . . . . . . . . . . . . . . . . . . . 37
2.4.3 ITU-TG.728LD-CELP . . . . . . . . . . . . . . . . . . . 38
2.4.4 ITU-TG.729CS-ACELP . . . . . . . . . . . . . . . . . . 38
2.4.5 ITU-TG.723.1MP-MLQ/ACELP . . . . . . . . . . . . . 39
2.4.6 ETSIGSM . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.4.7 ETSIAMR . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2.4.8 IETF’siLBC . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.4.9 Skype/IETF’sSILK . . . . . . . . . . . . . . . . . . . . . 41
2.4.10 ITU-TG.722ADPCM-WB . . . . . . . . . . . . . . . . . 42
vii
viii Contents
2.4.11 ITU-TG.722.1TransformCoding . . . . . . . . . . . . . 43
2.4.12 ETSIAMR-WBandITU-TG.722.2 . . . . . . . . . . . . 44
2.4.13 ITU-TG.719FullbandAudioCoding . . . . . . . . . . . . 44
2.4.14 SummaryofNarrowbandtoFullbandSpeechCodecs . . . 45
2.5 IllustrativeWorkedExamples . . . . . . . . . . . . . . . . . . . . 45
2.5.1 Question1 . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.5.2 Question2 . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.5.3 Question3 . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
2.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
3 VideoCompression . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.1 IntroductiontoVideoCompression . . . . . . . . . . . . . . . . . 53
3.2 VideoCompressionBasics . . . . . . . . . . . . . . . . . . . . . 55
3.2.1 DigitalImageandVideoColourComponents. . . . . . . . 55
3.2.2 ColourSub-sampling . . . . . . . . . . . . . . . . . . . . 56
3.2.3 VideoResolutionandBandwidthRequirement . . . . . . . 57
3.3 VideoCompressionTechniques . . . . . . . . . . . . . . . . . . . 58
3.4 LosslessVideoCompression . . . . . . . . . . . . . . . . . . . . 58
3.5 LossyVideoCompression . . . . . . . . . . . . . . . . . . . . . . 59
3.5.1 PredictiveCoding . . . . . . . . . . . . . . . . . . . . . . 59
3.5.2 Quantisation . . . . . . . . . . . . . . . . . . . . . . . . . 60
3.5.3 TransformCoding . . . . . . . . . . . . . . . . . . . . . . 61
3.5.4 InterframeCoding . . . . . . . . . . . . . . . . . . . . . . 62
3.6 VideoCodingStandards . . . . . . . . . . . . . . . . . . . . . . . 63
3.6.1 H.120 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3.6.2 H.261 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3.6.3 MPEG1&2 . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.6.4 H.263 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
3.6.5 MPEG-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.6.6 H.264 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.6.7 HighlyEfficiencyVideoCoding(HEVC) . . . . . . . . . . 69
3.7 IllustrativeWorkedExamples . . . . . . . . . . . . . . . . . . . . 69
3.7.1 Question1 . . . . . . . . . . . . . . . . . . . . . . . . . . 69
3.7.2 Question2 . . . . . . . . . . . . . . . . . . . . . . . . . . 70
3.7.3 Question3 . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.9 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
4 MediaTransportforVoIP . . . . . . . . . . . . . . . . . . . . . . . . 73
4.1 MediaTransportoverIPNetworks . . . . . . . . . . . . . . . . . 73
4.2 TCPorUDP? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
4.3 Real-TimeTransportProtocol—RTP . . . . . . . . . . . . . . . . 76
4.3.1 RTPHeader . . . . . . . . . . . . . . . . . . . . . . . . . 76
4.3.2 RTPHeaderforVoiceCallBasedonWireshark . . . . . . 78
4.3.3 RTPPayloadandBandwidthCalculationforVoIP . . . . . 80
Contents ix
4.3.4 IllustrativeWorkedExample . . . . . . . . . . . . . . . . 83
4.3.5 RTPHeaderforVideoCallBasedonWireshark . . . . . . 84
4.4 RTPControlProtocol—RTCP . . . . . . . . . . . . . . . . . . . . 88
4.4.1 RTCPSenderReportandExample . . . . . . . . . . . . . 89
4.4.2 RTCPReceiverReportandExample . . . . . . . . . . . . 91
4.4.3 RTCPSourceDescriptionandExample . . . . . . . . . . . 92
4.4.4 RTCPBYEPacketandExample . . . . . . . . . . . . . . 94
4.4.5 ExtendedRTCPReport—RTCPXRforVoIPMetrics . . . 95
4.5 CompressedRTP—cRTP . . . . . . . . . . . . . . . . . . . . . . 96
4.5.1 BasicConceptofCompressedRTP—cRTP . . . . . . . . . 96
4.5.2 IllustrativeWorkedExample . . . . . . . . . . . . . . . . 98
4.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
4.7 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
5 VoIPSignalling—SIP. . . . . . . . . . . . . . . . . . . . . . . . . . . 101
5.1 WhatisSessionInitiationProtocol? . . . . . . . . . . . . . . . . . 101
5.1.1 SIPNetworkElements. . . . . . . . . . . . . . . . . . . . 102
5.1.2 UserAgent . . . . . . . . . . . . . . . . . . . . . . . . . . 103
5.1.3 ProxyServer . . . . . . . . . . . . . . . . . . . . . . . . . 104
5.1.4 RedirectServer . . . . . . . . . . . . . . . . . . . . . . . 105
5.1.5 Registrar . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
5.1.6 LocationServer . . . . . . . . . . . . . . . . . . . . . . . 106
5.2 SIPProtocolStructure . . . . . . . . . . . . . . . . . . . . . . . . 106
5.2.1 SIPMessageFormat . . . . . . . . . . . . . . . . . . . . . 107
5.3 SessionDescriptionsProtocol . . . . . . . . . . . . . . . . . . . . 113
5.3.1 SessionDescription . . . . . . . . . . . . . . . . . . . . . 114
5.3.2 TimeDescription . . . . . . . . . . . . . . . . . . . . . . 115
5.3.3 MediaDescription . . . . . . . . . . . . . . . . . . . . . . 115
5.3.4 Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . 116
5.3.5 ExampleofSDPMessagefromWireshark . . . . . . . . . 117
5.4 SIPMessagesFlow . . . . . . . . . . . . . . . . . . . . . . . . . 117
5.4.1 SessionEstablishment . . . . . . . . . . . . . . . . . . . . 118
5.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
5.6 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
6 VoIPQualityofExperience(QoE) . . . . . . . . . . . . . . . . . . . 123
6.1 ConceptofQualityofService(QoS) . . . . . . . . . . . . . . . . 123
6.1.1 WhatisQualityofService(QoS)? . . . . . . . . . . . . . 123
6.1.2 QoSMetricsandMeasurements . . . . . . . . . . . . . . . 124
6.1.3 NetworkPacketLossandItsCharacteristics . . . . . . . . 125
6.1.4 Delay,DelayVariation(Jitter)andItsCharacteristics. . . . 130
6.2 QualityofExperience(QoE)forVoIP. . . . . . . . . . . . . . . . 135
6.2.1 WhatisQualityofExperience(QoE)? . . . . . . . . . . . 135
6.2.2 FactorsAffectVoiceQualityinVoIP . . . . . . . . . . . . 136
6.2.3 OverviewofQoEforVoiceandVideooverIP . . . . . . . 137
6.3 SubjectiveSpeechQualityAssessment . . . . . . . . . . . . . . . 138
x Contents
6.4 ObjectiveSpeechQualityAssessment. . . . . . . . . . . . . . . . 141
6.4.1 Comparison-Based Intrusive Objective Test (Full-
ReferenceModel) . . . . . . . . . . . . . . . . . . . . . . 141
6.4.2 Parameter-BasedMeasurement:E-Model . . . . . . . . . . 145
6.4.3 ASimplifiedandApplicableE-Model . . . . . . . . . . . 147
6.5 SubjectiveVideoQualityAssessment . . . . . . . . . . . . . . . . 148
6.6 ObjectiveVideoQualityAssessment . . . . . . . . . . . . . . . . 150
6.6.1 Full-Reference(FR)VideoQualityAssessment . . . . . . 150
6.6.2 Reduced-Reference(RR)VideoQualityAssessment . . . . 153
6.6.3 No-ReferenceVideoQualityAssessment . . . . . . . . . . 154
6.7 IllustrativeWorkedExamples . . . . . . . . . . . . . . . . . . . . 155
6.7.1 Question1 . . . . . . . . . . . . . . . . . . . . . . . . . . 155
6.7.2 Question2 . . . . . . . . . . . . . . . . . . . . . . . . . . 156
6.7.3 Question3 . . . . . . . . . . . . . . . . . . . . . . . . . . 157
6.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
6.9 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
7 IMSandMobileVoIP . . . . . . . . . . . . . . . . . . . . . . . . . . 163
7.1 WhatIsIPMultimediaSubsystem? . . . . . . . . . . . . . . . . . 163
7.1.1 WhatDoWeNeedIMSfor?. . . . . . . . . . . . . . . . . 163
7.1.2 IMSArchitecture . . . . . . . . . . . . . . . . . . . . . . 164
7.1.3 IMSElements . . . . . . . . . . . . . . . . . . . . . . . . 167
7.1.4 IMSServices. . . . . . . . . . . . . . . . . . . . . . . . . 173
7.1.5 IMSSignallingandBearerTrafficInterfaces . . . . . . . . 174
7.2 MobileAccessNetworks . . . . . . . . . . . . . . . . . . . . . . 177
7.2.1 CellularStandards . . . . . . . . . . . . . . . . . . . . . . 178
7.2.2 TheGSMStandard . . . . . . . . . . . . . . . . . . . . . 179
7.2.3 TheUMTSStandard . . . . . . . . . . . . . . . . . . . . . 181
7.2.4 Long-TermEvolution . . . . . . . . . . . . . . . . . . . . 186
7.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
7.4 Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
8 CaseStudy1—BuildingUpaVoIPSystemBasedonAsterisk . . . . 193
8.1 WhatisAsterisk? . . . . . . . . . . . . . . . . . . . . . . . . . . 193
8.1.1 ChannelModules . . . . . . . . . . . . . . . . . . . . . . 194
8.1.2 CodecTranslatorModules . . . . . . . . . . . . . . . . . . 194
8.1.3 ApplicationModules . . . . . . . . . . . . . . . . . . . . 195
8.1.4 FileFormatModules. . . . . . . . . . . . . . . . . . . . . 195
8.1.5 InstallingAsterisk . . . . . . . . . . . . . . . . . . . . . . 196
8.2 WhatIsX-Lite4 . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
8.2.1 UsingX-Lite . . . . . . . . . . . . . . . . . . . . . . . . . 197
8.3 VoiceandVideoInjectionTools . . . . . . . . . . . . . . . . . . . 201
8.3.1 ManycamVideoInjectionTool . . . . . . . . . . . . . . . 201
8.3.2 VirtualAudioCableInjectionTool . . . . . . . . . . . . . 202
8.4 LabScenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
8.5 AddingSIPPhones . . . . . . . . . . . . . . . . . . . . . . . . . 205