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

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

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 Spring 2014

Multimedia System/Network CS Spring 2014 Network MM Application OS/DS/Network MM Application OS/DS/Network SenderReceiver

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 Spring 2014

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 Spring 2014

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

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 Spring 2014

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 Spring 2014 Deterministic QoS Parameters

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 Spring 2014

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 Spring 2014

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 Spring 2014

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

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

Phase 1: Connection Establishment CS 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

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

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 Spring 2014

Layered Translation (Example) CS Spring 2014

QoS Negotiation CS Spring 2014

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 Spring 2014

Bilateral QoS Negotiation CS Spring 2014

Triangular QoS Negotiation CS Spring 2014

Triangular Negotiation with Bounded Value CS Spring 2014

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

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 Spring 2014