Internet Streaming Media Delivery:

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Delving into. Internet Streaming Media Delivery:. A quality and Resource Utilization Perspective. Zhen Xiao Joint work with Lei Guo, Enhua Tan, Songqing Chen, Oliver Spatchcheck, and Xiaodong Zhang. ACM SIGCOMM Internet Measurement Conference (IMC'06), October 2006. - PowerPoint PPT Presentation


<ul><li><p>Internet Streaming Media Delivery:Zhen Xiao Joint work with Lei Guo, Enhua Tan, Songqing Chen, Oliver Spatchcheck, and Xiaodong ZhangDelving intoA quality and Resource Utilization PerspectiveACM SIGCOMM Internet Measurement Conference (IMC'06), October 2006 </p></li><li><p>Multimedia on the InternetEducation and research</p><p>News media</p><p>Entertainment and gaming</p><p>Advertisement</p></li><li><p>Streaming MediaCDN/MDNStreaming server</p></li><li><p>Pseudo StreamingHTTP fileWeb server</p></li><li><p>Streaming MediaThousands of concurrent streams</p><p>Flexible response to network congestion</p><p>Efficient bandwidth utilization</p><p>High quality to end users</p><p>Challenges and techniques</p></li><li><p>Existing MeasurementsAccess pattern and user behaviorsA bunch of measurement studiesServer clusters, media proxies</p><p>Streaming mechanism and delivery qualityFew studies</p><p>Traffic volume Downloading &gt; pseudo streaming &gt; streaming (WWW05, cookie talk 2005)P2P &gt;&gt; all other media delivery systems</p></li><li><p>Our MeasurementInvestigate modern streaming servicesThe delivery quality and resource utilization</p><p>Collect a large streaming media workload From thousands of home users and business usersHosted by a large ISPPacket level instead of server logs</p><p>Analyze commonly used streaming techniquesAutomatic protocol switchFast StreamingMBR encoding and rate adaptation</p></li><li><p>OutlineTraffic overview</p><p>Protocol rollover</p><p>Fast Streaming</p><p>Rate adaptation</p><p>Conclusion</p></li><li><p>Traffic OverviewUser communitiesHome userBusiness user</p><p>Media hosting servicesSelf-hostingThird-party hosting</p></li><li><p>Number of requestsBusiness users access more audio than home users</p></li><li><p>On-demand media: File length Business users tend to access longer audio/video filesAudioVideopop songsmusic previews</p></li><li><p>On-demand media: Playback duration Business users tend to play audio/video longer AudioVideopop songsmusic previews</p></li><li><p>Live media: Playback duration Business users tend to access live audio/video longerAudioVideo</p></li><li><p>Traffic OverviewUser communitiesHome userBusiness userWorking environment affects access pattern</p><p>Media hosting servicesSelf-hostingThird-party hostingNews and entertainment sites</p></li><li><p>Traffic OverviewUser communitiesBusiness users tend to access streaming media longer than home usersWorking environment affects access pattern</p><p>Media hosting servicesSelf-hostingThird-party hosting</p></li><li><p>Media hosting services</p></li><li><p>OutlineTraffic overview</p><p>Protocol rollover</p><p>Fast Streaming</p><p>Rate adaptation</p><p>Conclusion</p></li><li><p>Protocol RolloverStreaming serverRTSP/UDPRTSP/TCPHTTP/TCPEmbed RTSP commands in HTTP packetsMedia playerTraffic volume:UDP: 23%TCP: 77%HTTP: rare</p></li><li><p>Protocol rollover timeWindows media serviceRealNetworks media serviceProtocol rollover increases user startup time significantlyStartup latency = protocol rollover time + transport setup time + startup buffering time</p></li><li><p>Protocol selection and rollover avoidanceMost streaming traffic are TCP-basedThe usage of NAT?MMS clients report private IP address in clear textHome user: 98.3% report 192.168.*.*Business user: 89.5% report 192.168.*.*</p><p>Protocol rollover sessions are minorHome user: 7.37%Business user: 7.95%</p><p>Most streaming sessions use TCP directlyWhy?</p></li><li><p>Protocol selection and rollover avoidanceWindows media serviceSpecify the protocol in the media meta fileUse URL modifiers to avoid protocol rolloverEx: rtspt:// than 70%RealNetworks media serviceNAT transversal techniques</p></li><li><p>OutlineTraffic overview</p><p>Protocol rollover</p><p>Fast Streaming</p><p>Rate adaptation</p><p>Conclusion</p></li><li><p>Fast StreamingFast Streaming: deliver media data faster than its encoding rateFast startFast cacheFast recoveryFast reconnectAlways TCP-based</p></li><li><p>Media objects delivered with Fast Cache(VoD home user workload)File lengthEncoding rateFast Cache is more widely used for media files with longer length and higher encoding rate.</p></li><li><p>Bandwidth UtilizationPLAY RTSP/1.0Bandwidth: 1.12 MbpsSpeed: 20.5RTSP /1.0 200 OKSpeed: 5Fast CacheNormal TCP</p></li><li><p>Fast Cache smooth bandwidth fluctuationRebuffer ratio = rebuffer time / play timeFast CacheNormal TCP</p></li><li><p>Fast Cache produces extra trafficMost streaming sessions only request the initial part of a media objectOver supplied dataFast Cache: 55%Normal TCP: 5%</p></li><li><p>Server response timeThird party media serviceSelf-hosting media serviceDESCRIBE foo.wmv RTSP/1.0RTSP /1.0 200 OKSDPRTTSRTsniffer</p></li><li><p>Server LoadWindows media load simulatorWindows Server 2003Win XPServer logEthernet 1 X 4 XSome CDNs/MDNs do not support Fast Cache at all</p></li><li><p>OutlineTraffic overview</p><p>Protocol rollover</p><p>Fast Streaming</p><p>Rate adaptation</p><p>Conclusion</p></li><li><p>Rate Adaptation 96Kbps128Kbps320Kbps 1.128MbpsMultiple-bit-rate encodingStream switchWM: Intelligent streaming RM: SureStreamStream thinning: deliver key frame onlyVideo cancellation</p></li><li><p>MBR encodingon-demand audiolive audioaudio stream in video objectsvideo stream in video objects42% on-demand video are MBR encoded</p></li><li><p>Stream switch30 sec60%Streaming switch latencyLow quality duration3 sec40%Play-out bufferStream switch is often not smooth</p></li><li><p>Stream thinning30 sec70%</p></li><li><p>Fast Cache and stream switch Do not work with each other: fewer stream switches than MBR encoded objectsplayingbufferingplayingbufferingbufferingplaying5 secWhen network congestion occurs Like pseudo streamingWhen rebuffer occurstimefill play-out buffer</p></li><li><p>Streaming quality and playback durationHome userbusiness userLonger duration sessions have higher prob. of quality degradationBusiness user workload has more quality degradation&gt;100 sec88%</p></li><li><p>Streaming quality summaryThe quality of media streaming on the Internet leaves much to be improved</p></li><li><p>Coordinating caching and rate adaptationFast Cache: aggressively buffer data in advanceOver-utilize CPU and bandwidth resourcesNeither performance effective nor cost-efficientRate adaptation: conservatively switch to lower bit rate streamSwitch handoff latencyCoordinated StreamingUpper boundPrevent aggressive bufferingLower boundPrevent switch latency</p></li><li><p>Coordinated StreamingRebuffering ratioOver-supplied dataSwitch latency</p></li><li><p>ConclusionQuality of Internet streamingOften unsatisfactoryNeed to improve</p><p>Modern streaming media servicesOver-utilize CPU and bandwidth resourcesNot a desirable way to improve quality</p><p>Coordinated StreamingCombine merits of both caching and rate adaptationSimple but effective</p><p>In 2000, 9,000 narrowband and 2,400 broadband video streams on a single physical server</p></li></ul>


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