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

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

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

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

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) CS 414 - Spring 2014 QoS Class determines: (a) reliability of offered QoS, (b) utilization of resources

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. Single Value: QoS 1 – average (QoS ave ), contractual value, threshold value, target value Bandwidth, specified by average need 10 Mbps Pair Value: with QoS 1 – required value; QoS 2 – desired value ; Bandwidth, specified by required and desired values Mbps CS 414 - Spring 2014 Deterministic QoS Parameters

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: 1. Hard upper bounds for imposed workloads 2. Worst case assumptions about system behavior 1. Advantages: QoS guarantees are satisfied even in the worst case (high reliability in guarantees) 2. Disadvantage: Over-reservation of resources, hence needless rejection of requests CS 414 - Spring 2014

11. Predictive QoS Parameters We utilize QoS values (QoS 1,..QoS i ) and compute average  QoS bound step at K>i is QoS K = 1/i*∑ j QoS j We utilize QoS values (QoS 1,, QoS i ) and compute maximum value  QoS K = max j=1,…i (QoS j ) We utilize QoS values (QoS 1,, QoS i ) and compute minimum value  QoS K = min j=1,…i (QoS j ) 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) CS 414 - Spring 2014 Translation, Negotiation Admission, Reservation

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 CS 414 - Spring 2014 Network MM Application OS/DS/Network MM Application OS/DS/Network SenderReceiver Translation Logical Negotiation of Network QoS Parameters Physical Transmission of Negotiation Parameters Logical Negotiation of Application QoS Parameters

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

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) CS 414 - Spring 2014 CallerCallee Network-Service Provider Pseudo-Code Caller Pseudo-Code Callee Pseudo-Code

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