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CS 414 – Multimedia Systems Design Lecture 17 – QoS Classes and Setup Operations

CS 414 – Multimedia Systems Design Lecture 17 – QoS Classes and Setup Operations. Klara Nahrstedt Spring 2014. Administrative. HW1 posted HW1, deadline, March 3 Midterm March 7 (Friday) in class. Covered Aspects of Multimedia. Audio/Video Presentation Playback. Image/Video Capture.

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CS 414 – Multimedia Systems Design Lecture 17 – QoS Classes and Setup Operations

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  1. CS 414 – Multimedia Systems DesignLecture 17 – QoS Classes and Setup Operations Klara Nahrstedt Spring 2014 CS 414 - Spring 2014

  2. Administrative • HW1 posted HW1, deadline, March 3 • Midterm March 7 (Friday) in class CS 414 - Spring 2014

  3. Covered Aspects of Multimedia Audio/Video Presentation Playback Image/Video Capture Audio/Video Perception/ Playback Image/Video Information Representation Transmission Transmission Compression Processing Audio Capture Media Server Storage Audio Information Representation A/V Playback CS 414 - Spring 2014

  4. Multimedia System/Network Sender Receiver MM Application MM Application OS/DS/Network OS/DS/Network Network CS 414 - Spring 2014

  5. Quality of Service Concept • Differentiation of services based on desired service quality, given by parameters • Throughput • Bandwidth • End-to-end Delay • Round-trip Delay • Packet Loss Rate CS 414 - Spring 2014

  6. Other QoS Parameters • Jitter • Undesired deviation from true periodicity in telecommunication • Also called packet delay variation – important QoS factor in assessment of network performance • Packet jitter – variation in latency as measured in the variability over time of the packet latency across network. CS 414 - Spring 2014

  7. Quality of Service Classes (platinum, gold, silver) QoS Class determines: (a) reliability of offered QoS, (b) utilization of resources CS 414 - Spring 2014

  8. QoS Classes • Guaranteed Service Class • QoS guarantees are provided based on deterministic and statistical QoS parameters • Voice Networks (AT&T) • Predictive Service Class • QoS parameter values are estimated and based on the past behavior of the service • Video Networks (Comcast Cable Network) • Best Effort Service Class • There are no guarantees or only partial guarantees are provided • Data Networks (Other Internet Service Providers) CS 414 - Spring 2014

  9. Deterministic QoS Parameters Single Value: QoS1 – average (QoSave), contractual value, threshold value, target value Bandwidth, specified by average need 10 Mbps Pair Value: <QoS1, QoS2> with QoS1 – required value; QoS2 – desired value <QoSavg,QoSpeak>; <QoSmin, QoSmax> Bandwidth , specified by required and desired values <8,12> Mbps CS 414 - Spring 2014

  10. Guaranteed QoS • We need to provide 100% guarantees for QoS values (hard guarantees) or very close to 100% (soft guarantees) • Current QoS calculation and resource allocation are based on: • Hard upper bounds for imposed workloads • Worst case assumptions about system behavior • Advantages:QoS guarantees are satisfied even in the worst case (high reliability in guarantees) • Disadvantage: Over-reservation of resources, hence needless rejection of requests CS 414 - Spring 2014

  11. Predictive QoS Parameters • We utilize QoS values (QoS1, ..QoSi) and compute average • QoSbound step at K>i is QoSK = 1/i*∑jQoSj • Weutilize QoS values (QoS1, , QoSi) and compute maximum value • QoSK = max j=1,…i (QoSj) • We utilize QoS values (QoS1, , QoSi) and compute minimum value • QoSK = min j=1,…i (QoSj) CS 414 - Spring 2014

  12. Best Effort QoS No QoS bounds or possible very weak QoS bounds Advantages: resource capacities can be statistically multiplexed, hence more processing requests can be granted Disadvantages: QoS may be temporally violated CS 414 - Spring 2014

  13. Relation between QoS and Resources (Phase 1) Admission, Reservation Translation, Negotiation CS 414 - Spring 2014

  14. Phase 1: Establishment Phase (QoS Operations) CS 414 - Spring 2014 • QoS Translation at different Layers • User-Application • Application-OS/Transport Subsystem • QoS Negotiation • Negotiation of QoS parameters among two peers/components

  15. Phase 1: Connection Establishment Logical Negotiation of Application QoS Parameters Sender Receiver MM Application MM Application Translation OS/DS/Network OS/DS/Network Logical Negotiation of Network QoS Parameters Physical Transmission of Negotiation Parameters Network CS 414 - Spring 2014

  16. QoS Operations within Establishment Phase User/Application QoS Translation Overlay P2P QoS Negotiation Application/Transport QoS Translation QoS Negotiation in Transport Subsystem CS 414 - Spring 2014

  17. Example • Video Stream Quality: • Frame size: 320x240 pixels, 24 bits (3 Bytes per pixel) • Application frame rate RA: 20 fps • Translate to Network QoS if • Assume network packet size is 4KBytes • Network packet rate (RN):= ┌320x240x3x20┐ bytes / 4096 bytes CS 414 - Spring 2014

  18. Layered Translation (Example) CS 414 - Spring 2014

  19. QoS Negotiation CS 414 - Spring 2014

  20. Different Types of Negotiation Protocols • Bilateral Peer-to-Peer Negotiation • Negotiation of QoS parameters between equal peers in the same layer • Triangular Negotiation • Negotiation of QoS parameters between layers • Triangular Negotiation with Bounded Value CS 414 - Spring 2014

  21. Bilateral QoS Negotiation CS 414 - Spring 2014

  22. Triangular QoS Negotiation CS 414 - Spring 2014

  23. Triangular Negotiation with Bounded Value CS 414 - Spring 2014

  24. Triangular Negotiation Protocol (Pseudo-Code Example) Caller Callee Caller Pseudo-Code Network-Service Provider Pseudo-Code Callee Pseudo-Code CS 414 - Spring 2014

  25. Conclusion • Different classes of services differentiated by different levels of Quality of Service • Guaranteed Service class (platinum) • Predictive Service class (gold) • Best Effort Service class (silver) • Two major operations on the Quality parameters • Translation of parameters (needed due to layered network structure) • Negotiation of parameters (needed due to distributed nature of multimedia networks) CS 414 - Spring 2014

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