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Video Transport Architectures Thomas Kernen, IJsbrand Wijnands BRKSPV-2919 Agenda • Introduction • Solution Space • Video Transport Use Cases • QoS • IP/MPLS Video Transport • IP Multicast Transport Options • Problem Space & Requirements • Label Switched Multicast • Minimizing Failure/Recovery Loss • Bounded Delay & Jitter • Auto Multicast Tunneling • Video & Packet Loss • Bit Index Edge Replication • Zero Loss Options • Video Monitoring Broadcast Media Content Delivery High level view Acquisition Production Distribution Consumer Experience BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 4 Video Transport Use Cases Video Transport Use Cases Contribution • Video Contribution • Studio-to-Studio Primary • Primary Distribution Distribution • Owner to Distributor • Secondary Distribution Secondary • IPTV, Cable, Mobile, DVB-T Distribution • SP CDN/Internet Streaming • Enterprise Video • Multicast VPNs • In all cases, point-to-point AND multipoint services over Private OR SP infrastructure are required BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 6 Bandwidth & Formats Studio and Remote Primary Secondary Consumer Contribution Post Production Distribution Distribution Experience Production Studio to Studio Owner to Provider Provider to Subscriber Uncompressed/Lossless compression Compressed (High quality) Compressed - SD: 270 Mbps (SMPTE ST 259) P-to-P P-to-MP - SD: 2 – 6 Mbps - HD: 1.5 – 3 Gbps (SMPTE ST 292, ST 372, ST 424) P-to-MP for DTT/DVB-T - HD: 6 – 16 Mbps - UHD: 12 Gbps (SMPTE ST 2082) P-to-P for VoD P-to-P, MP-to-P, P-to-MP P-to-MP for IPTV “Dial up” approach (ATM SVC very common) May be wholesaled Stricter Requirements, Higher per-flow bandwidth BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 7 IP/MPLS Video Transport Overview and General Concepts The Road to IP DTM • TDM based networks provide uniform services IP/MPLS • Circuit-oriented with Circuit-based protection Si • No bandwidth sharing Transport • ATM/DTM networks provide specialized services • Granular bandwidth with switching capabilities Video : A new layer for each service • Specific overlays per service • IP/MPLS networks are multi-service • Flexible bandwidth re-utilization • Co-existence of strict and loose SLA applications IP/MPLS • Future proof Video: Just a new service BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 9 Video Transport: Requirements and Attributes Performance Impact Goal Solution Technology of Delay Service SLAs Resiliency Path Diversity Traffic Guaranteed bandwidth Engineering Transport SLAs Delay Planning y Loss FRR x% 100% Average Link Simplicity KISS IP Utilisation Manageability Video Monitoring VidMon Contribution Flexibility MultiService QoS Distribution Scalability & File Transfer Unified CP for Multicast LSM Multipoint BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 10 Video Transport: • Packetization/Encapsulation • Uncompressed A/V, MPEG-2 TS and MXF wrappers • Adaptation/Profiling • RTP: Sequencing and Timestamp • Transport • UDP: Multiplexing and Checksum • Network • IP: QoS, Multi-service • Traffic Engineering • MPLS: Path selection, Admission control, Bandwidth Reservation BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 11 Video Transport: Quality of Service Contribution • Required to enable multiple services Distribution • Elastic and inelastic (sensitive to loss and delay) File Transfer • Differentiated services (per traffic aggregate) • Marking, Conditioning, Queuing, … (the IP QoS toolkit) • Handling a variety of traffic classes in a single network • Integrated services (per flow) • Allowing for service oversubscription • Video CAC (Call Admission Control) • Delay and Jitter requirements for Video transport are satisfied by modern routing equipment BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 12 Multiple requirements, multiple options • P2P, P2MP and MP2MP services IP/MPLS • Unicast and Multicast models • IP and MPLS • Single, multi-topology • (m)VPNs • Automatic (shortest path) or Explicit path setup • Admission Control and Bandwidth Reservation • MPLS-TE with RSVP based label distribution • Resiliency: from sub 50 msec restoration to lossless • IP FRR • MPLS FRR for link and node protection BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 13 Bounded Delay and Jitter Components of Delay in IP / MPLS Networks • The dominant causes of delay in IP / MPLS networks are: • Propagation delay • Arising from speed-of-light delays on wide area links; ~5ms per 1000km for optical fibre • Queuing delays – in switches and routers • Other components of delay are negligible for links of 1Gbps and over • Serialization delay: ~10µs for 1500 byte packet at 1Gbps, 1µs for 10 Gbps, 0.1µs for 100Gbps link • Switching delay: typically 1µs per hop (with modern fabric) • Propagation delays are a fixed property of the topology • Delay and jitter are minimized when queuing delays are minimized • Queuing delays depend upon the traffic profile BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 15 IP / MPLS Traffic Characterization • Network traffic measurements are 100% normally long term, i.e. in the order of minutes failure & growth • Implicitly the measured rate is an average of the measurement interval micro-bursts • In the short term, i.e. milliseconds, however, microbursts cause queueing, impacting the delay, jitter and loss • What’s the relationship between the measured load and the short term measured traffic microbursts? 0% 24 hours BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 16 Per Hop Queueing Delay vs. Utilisation [Telkamp] BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 17 Multi-hop Queuing [Telkamp] Multi-hop delay is not additive (1Gbps) 1 hop 2 hops Avg: 0.23 ms Avg: 0.46 ms P99.9: 2.02 ms P99.9: 2.68 ms BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 18 Quality of Service Operations How Do QoS Tools Work? Classification Queuing and Post-Queuing and Marking (Selective) Dropping Operations BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 19 Video and Packet Loss MPEG : Impact of Packet Loss 1200 1000 SD-low -w orst 800 SD-low -best SD-high-w orst SD-high-best 600 HD-low -w orst HD-low -best 400 HD-high-w orst HD-high-best Durationof impairment (ms) 200 0 0 100 200 300 400 500 Duration of packet loss (ms) . Single Packet loss can cause artifacts for the whole GOP period – 500ms (I frame pkt loss) . [GREENGRASS]: Jason Greengrass, John Evans, Ali C. Begen, “Not All Packets Are Equal: The Impact of Network Packet Loss on Video Transport” – IEEE Internet Computing, Nov 08 BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 21 ABR (adaptive bitrate video) • ABR normally HTTP(s) (unicast), not RTP • Payload are segments of MPEG/H26x media • ABR can be very bursty • Sequence of segment@max-speed, idle, segment@max-speed, idle,.. • Competing ABR flows can cause mutual congestion collapse • Network QoS and ABR “self-friendliness” required • Some Limited standards for ABR over IP multicast • 3G, upcoming in cable (OC-SP-MS-EMCI-I01-150528) • Still transporting a segment that needs to arrive without loss • ABR sender need to use FEC instead of TCP retransmissions. BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 22 Types of Loss • Congestion / oversubscription • Elasticity of the traffic • Inelastic – classic broadcast • Partial elastic – ABR • Elastic – “TCP like” – sender bitrate adaptation (uncommon in broadcast video) • BER – Bit Error Rate Loss • Link quality • Failure/Recovery • Link, Interface, Linecard, Node, Power,.. • Elastic links • DSL retraining • WiFi, Mobile, Powerline BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 23 Quality of Service (QoS) General QoS Guidelines • DiffServ QoS model • Works on aggregate traffic classes rather than individual flows • Highly scalable (any number of eg: video channels – just < ~ 20 classes of QoS). • Best effort traffic can reuse non-utilized bandwidth • Real-time traffic classes with preferential treatment (Voice, Video) • Strict Priority when no Voice services are provided otherwise non-strict Priority • AF class with Voice when single PQ • Real-time traffic policed at ingress to avoid misconfiguration issues • Data services run as Best Effort traffic • Business traffic uses in-profile/out-profile QoS approach BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 25 QoS Cheat Sheet • Do not mix UDP & TCP traffic in the same class • Do not mix Voice & Video traffic in the same class • Per-subscriber SLA for Voice and Data applications • Per-subscriber SLA not applicable to Video/IPTV • Over-the-top (Internet) Video traffic to be treated as default traffic • With Dual Priority queue • Use priority level 1 for Voice traffic • Use priority level 2 is for Video traffic • With Single Priority queue • Use priority queue for Voice traffic • Use AF queue with minimum bandwidth guarantee for video BRKSPV-2919 © 2017 Cisco and/or its affiliates. All rights reserved. Cisco Public 26 Queues Distribution QoS 4Q queuing model example (A+B+C+D=100) PQ high Multi-Play Application Traffic DSCP / EXP priority A% of Link BW Broadcast Video AF41
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