A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Optimization of Video Serv rvices by SDN-Assisted Edge Computing A. Murat Tekalp Department of Electrical and Electronics Engineering, Koç University, Istanbul, Turkey
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 • Introduction Contents • Video Services over IP • Edge Computing @NSP Edges • Virtualization of Video Services @NSP Edges • vCDN: SDN-Assisted HAS Services • IPTV Services by SDN-Assisted IP Multicasting • vSFU: SDN-Assisted WebRTC Services • Managing Video Services @NSP Edges • Emerging NSP-Managed Video Services • Traffic Engineering at SDN-enabled NSP Edge • Path Computation • QoS Provisioning • NSP-Managed HAS and WebRTC Services • Conclusions
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Introduction – Evolution of IP Video • CDN • Akamai (1999), Google, NetFlix • Improvements in Video Coding/Streaming • MPEG2 (1996) MPEG4-AVC/H.264 (2003) HEVC/H.265 (2013) VP9/AV1 • RTP/UDP/IP push HTTP Adaptive Streaming - HTTP/TCP/IP pull (2007) • Improvements in Networking • Better Connectivity (wireline and wireless) 3G 4G 5G • NSP Edge Computing
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 State of the Art in Video Services • Over-The-Top (OTT) • Offered by third party content providers over the open unmanaged Internet • Providers rely on the best-effort service offered by the network service providers • VOD, Live streaming, Interactive communications services • IPTV • Offered by network operators over managed IP networks • Packets travel over closed IP network, IP multicast via the Central Office (PoP) • Quality-of-Service (QoS) enabled differentiated video service
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Brief History of Edge Computing W. Shi, G. Pallis, Z. Xu, Edge Computing, Proceedings of the IEEE, vol. 107, no. 8, pp. 1474-1481, August 2019.
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Where is the Edge and Who Owns it? • Operated by Cloud Service Provider – CDN: OTT video @ the network edge • Best-Effort from the CDN node to end-user – No end-to-end quality of service (QoS) A. Vakali and G. Pallis, Content delivery networks: Status and trends, IEEE Internet Comput., vol. 7, no. 6, pp. 68-74, Nov. 2003. • Operated by Network Service Provider – IPTV multicast @ NSP point of presence • Can provide QoS from the edge to end-user over reserved network slices
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 IPTV: IP-Multicasting • Multicasting is fundamental to the implementation of IPTV. IGMP snooping ON IGMP snooping ON Three different channels Three different channels IGMP snooping ON IGMP query ON Broadcasting Multi-cast enabled network Network NOT multi-cast enabled IGMP- Internet Group Management Protocol
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 OTT Video Services OTT Video Service Providers Network Service Providers Problem: Provide lower delay Problem: Optimize network resource Video on Demand (HAS) higher throughput service consumption, increase revenue Cloud or CDN Live Streaming (HAS) End Users Problem: Receive better video quality and lower latency Real-Time Communications (WebRTC)
A. Murat Tekalp A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 CDN: Physical Servers Physical servers at centralized facilities and peering locations
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 OTT Video CDN @NSP Edge Open Connect by Netflix • Netflix partners with ISPs to localize substantial amounts of traffic by deploying embedded Open Connect Appliances at edge points of presence. OCA that is embedded in a partner network Peering without deploying embedded OCAs in the partner network • Netflix uses a popularity-based algorithm to determine what content should be on the appliances. A number of factors affect popularity, and the contents of an appliance are expected to change on a daily basis.
A. Murat Tekalp A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 vCDN Virtual CDNs leverage shared physical servers Virtual CDNs can be orchestrated – VNF and MANO-like orchestration https://www.akamai.com/us/en/resources/library.jsp?type=t18&bm=a#stp=1
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Adaptive Video Streaming Best-Effort Streaming Services: Serve at multiple resolutions and bitrates • Adapt the video resolution to display capability of receivers • Different spatial and temporal resolutions to different receivers, e.g., 1080p, 720p, 480p, 360p • Adapt the video bitrate to available network rate • Different bitrates to different receivers
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Video Coding for Adaptive Streaming • Stream Switching • Encode source video at multiple resolutions and bitrates e.g., 1080p, 720p, 480p, 360p • Scalable Video Coding (SVC) • Multiple spatial and temporal resolution layers in the same video bit stream Example: Two spatial and three temporal layers
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 HTTP Adaptive Streaming (HAS) • When a client requests a video title, the server first sends an MPD file, which lists available video chunks encoded at different resolutions and rates. • The client app requests video chunks whose resolution and bitrate match its display resolution and current available channel rate. • Problems: • Server-side congestion: Video service providers deploy or rent CDN clouds to avoid server congestion and provide lower service latency. • Network congestion: Multiple HAS flows on the same link compete with each other for available bitrate. TCP congestion control mechanism causes unwanted rate/ video quality fluctuations.
A. Murat Tekalp A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Common Media Application Format (CMAF) • Unified packetizer format based on fragmented MP4 (fMP4) • Apple HLS used to use M2TS packetization. With CMAF, the use of M2TS for video streaming is deprecated. • The codec and DRM wars still continue … Compatible with AV1 video codec Alliance for Open Media (AOM) • Non-multiplexed and precisely aligned (synchronized) streams • Encryption (CENC: CBC or CTR) • Audio codecs (AAC or optionally multi-channel) • Captions, subtitles (WebVTT or ISMC1) https://www.unified-streaming.com/blog/promises-cmaf-and-its-compatibility-unified-streaming-platform
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Real-Time Communications (RTC) • Session initiation • Media streams • Signaling Server • P2P between two peers • Multi-party RTC service architectures Cloud Mesh MCU SFU Non-scalable (default) or scalable video Nonscalable video Scalable video • Problems: Transcoding at the MCU • Guaranteed low-delay service • Efficient use of network resources
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 Mesh-Connected WebRTC Services • Advantages Best Effort • Easy to implement. • No Cloud or Edge Server Low end-to-end latency. • Drawbacks • Limited peer upload capacity • Limiting receiving peer factor (in case of non-scalable video coding) • Default: Clients run non-scalable video codec • Adaptive: Clients run a SVC enabled encoder • Ability to adapt different receiver terminal types. • Ability to adapt different receiving bandwidth capacities. G. Bakar, R. A. Kirmizioglu, and A. M. Tekalp, “Motion -based rate adaptation in WebRTC videoconferencing using scalable video coding,” IEEE Trans. on Multimedi a, vol. 21, no. 2, pp. 429-441, Feb. 2019.
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 SFU-Connected WebRTC Services Best Effort Selective Forwarding Unit Media Server • Advantages • Single video upstream architecture (overcomes limited peer upload capacity problem) • SVC enabled service for different receiver terminal types. • Drawbacks • High end-to-end service latency. • High network resource consumption. • Single point of failure. • Traffic overload since all video traffic must go through the SFU.
A. Murat Tekalp ACOSIS 2019 Marrakech, Morocco November 20-22, 2019 MEC • Mobile Edge Computing • End users off-load computation from mobile devices to edge servers • Multi-access Edge Computing • Telcos use edge servers to manage fixed and radio access networks Multiple access capability: Users can access the same service deployed at the edge of the network and obtain the same user perception no matter whether they access the network through 4G, 5G, or even fixed networks. Compute capability: Edge servers and accelerated hardware devices such as GPU/FPGA, together with the edge ICT cloud platform, provide computing, storage, and acceleration capabilities to applications at the edge. Service enablement capability: Enables provisioning carrier-grade or third-party services at the edge. A. Wang, Z. Zha, Y. Guo and S. Chen, Software-defined networking enhanced edge computing: A network-centric survey, Special Issue of the Proc. of the IEEE on Edge Computing, vol. 107, no. 8, pp. 1500-1519, August 2019.
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