CS 414 Multimedia Systems Design Lecture 14 Quality

CS 414 – Multimedia Systems Design Lecture 14 – Quality of Service Concepts(P 2) Klara Nahrstedt Spring 2011 CS 414 - Spring 2011

Administrative HW 1 posted today, February 21 n HW 1 deadline, March 2 n CS 414 - Spring 2011

Multimedia System/Network Sender Receiver MM Application OS/DS/Network CS 414 - Spring 2011

Relation between Qo. S and Resources (Phase 1) Admission, Reservation Translation, Negotiation CS 414 - Spring 2011

Phase 1: Establishment Phase (Qo. S Operations) n Qo. S Translation at different Layers ¨ User-Application ¨ Application-OS/Transport n Subsystem Qo. S Negotiation ¨ Negotiation of Qo. S parameters among two peers/components CS 414 - Spring 2011

Phase 1: Connection Establishment Sender MM Application OS/DS/Network Logical Negotiation of Application Qo. S Parameters Translation Logical Negotiation of Network Qo. S Parameters Physical Transmission of Negotiation Parameters Network CS 414 - Spring 2011 Receiver MM Application OS/DS/Network

Qo. S Operations within Establishment Phase User/Application Qo. S Translation Overlay P 2 P Qo. S Negotiation Application/Transport Qo. S Translation Qo. S Negotiation in Transport Subsystem CS 414 - Spring 2011

Example n Video Stream Quality: ¨ Frame size: 320 x 240 pixels, 24 bits (3 Bytes per pixel) ¨ Application frame rate RA: 20 fps n Translate to Network Qo. S if ¨ Assume network packet size is 4 KBytes ¨ Network packet rate (RN): = ┌320 x 240 x 3┐ bytes / 4096 bytes CS 414 - Spring 2011

Layered Translation (Example) CS 414 - Spring 2011

Qo. S Negotiation CS 414 - Spring 2011

Different Types of Negotiation Protocols n Bilateral Peer-to-Peer Negotiation ¨ Negotiation of Qo. S parameters between equal peers in the same layer n Triangular Negotiation ¨ Negotiation of Qo. S parameters between layers n Triangular Negotiation with Bounded Value CS 414 - Spring 2011

Bilateral Qo. S Negotiation CS 414 - Spring 2011

Triangular Qo. S Negotiation CS 414 - Spring 2011

Triangular Negotiation with Bounded Value CS 414 - Spring 2011

Triangular Negotiation Protocol (Pseudo-Code Example) Caller Callee Caller Pseudo-Code Network-Service Provider Pseudo-Code Callee Pseudo-Code CS 414 - Spring 2011

Multimedia Resource Management n Resource managers with operations and resource management protocols n n Phase 1: Establishment Phase (resource operations) n n Various operations must be performed by resource managers in order to provide Qo. S Operations are executed where schedulable units utilizing shared resources must be admitted, reserved and allocated according to Qo. S requirements Phase 2: Enforcement Phase n Operations are executed where reservations and allocations must be enforced, and adapted if needed CS 414 - Spring 2011

Phase 1: Resource Preparation Operations n n Qo. S to Resource Mapping ¨ Need translation or profiling (e. g. , how much processing CPU cycles, i. e. , processing time, it takes to process 320 x 240 pixel video frame) Resource Admission ¨ Need admission tests to check availability of shared resources Resource Reservation ¨ Need reservation mechanisms along the end-toend path to keep information about reservations Resource Allocation CS 414 - Spring 2011

Phase 1: Connection Establishment Sender MM Application OS/DS/Network System Resource Admission and Reservation Logical Negotiation of App Qo. S Parameters Receiver MM Application Translation Logical Negotiation of Net Qo. S Parameters OS/DS/Network Physical Transmission of Negotiation Parameters Network Resource Reservation Protocol Network CS 414 - Spring 2011 Network Resource Admission and Resource Reservation

Admission Tests n Task (System) schedulability tests for CPU resources ¨ n Network Packet schedulability tests for sharing host network interfaces, network switches ¨ n This is done for network delay and jitter guarantees Spatial tests for memory/buffer allocation ¨ n This is done for delay guarantees This is done for delay and reliability guarantees Network Link bandwidth tests ¨ This is done for network throughput guarantees CS 414 - Spring 2011

Resource Reservation and Allocation n Two types of reservations ¨ Pessimistic approach - Worst case reservation of resources ¨ Optimistic approach - Average case reservation of resources n To implement resource reservation we need: ¨ Resource n table to capture information about managed table (e. g. , process management PID table) ¨ Reservation n to capture reservation information ¨ Reservation n table function to map Qo. S to resources and operate over reservation table CS 414 - Spring 2011

Resource Reservation n Two types of reservation styles: ¨ Sender-initiated reservation ¨ Receiver-initiated reservation CS 414 - Spring 2011

Relation between Qo. S and Resources (Phase 2) Admission, Reservation Translation, Negotiation Compression Scheduling, Rate Control, Error Control Flow Control Qo. S Management CS 414 - Spring 2011

Phase 2: Media Processing and Transmission Sender MM Application OS/DS/Network Receiver MM Application System Resource • Scheduling • Rate Control • Flow Control Error Control OS/DS/Network Physical Transmission of Media Network Resource Scheduling CS 414 - Spring 2011

Phase 2: Enforcement Operations n Resource scheduling ¨ Example: rate-monotonic scheduling n Rate control – traffic shaping ¨ Example: n End-to-end error control ¨ Example: n leaky bucket forward error correction Flow control ¨ Open loop flow control (no feedback) ¨ Close look flow control (with feedback channel) CS 414 - Spring 2011

Qo. S Management during Transmission Phase n Resource and Qo. S Monitoring ¨ Flexibility, i. e. , monitoring should be turned on/off ¨ Two n n n types of monitoring User-mode monitoring Network-mode monitoring Qo. S Maintenance ¨ Compares n monitored Qo. S with contract Qo. S Degradation ¨ graceful degradation needed CS 414 - Spring 2011

Qo. S Management during Transmission Phase n Qo. S Renegotiation and Signaling ¨ In case Qo. S parameters need to change, renegotiation must be initiated n Qo. S/Resource Adaptation ¨ As a result of re-negotiation request (request for change in quality) adaptation in Qo. S and resource allocation must happen CS 414 - Spring 2011

Qo. S/Resource Adaptation n Renegotiation request can come from ¨ User ¨ Host system ¨ Network n Resource adaptation ¨ Network adaptation (e. g. , dynamic re-routing mechanism) ¨ Source adaptation (e. g. , temporal scaling with feedback) CS 414 - Spring 2011

Resource De-allocation – Tear. Down Phase Reserved Resource must be freed up once multimedia session is over n Tear-down process n ¨ Sender-initiated closing (release reservation) ¨ Receiver-initiated closing (release reservation) CS 414 - Spring 2011

Conclusion – Current State of Art n Lack of mechanisms to support Qo. S guarantees ¨ Need research in distributed control, monitoring, adaptation and maintenance of Qo. S mechanisms n Lack of overall frameworks ¨ Need Qo. S frameworks for heterogeneous environments (diverse networks, diverse devices, diverse OS) CS 414 - Spring 2011