Distributed Multimedia Systems - Distributed Operating Systems - Lecture Slides, Slides of Computer Science

Download Distributed Multimedia Systems - Distributed Operating Systems - Lecture Slides and more Slides Computer Science in PDF only on Docsity! Distributed Multimedia Systems Docsity.com Introduction • Most multimedia is inherently time-based – the arrival time and arrival order of data packets is important • The Internet guarantees neither when transmitting data • We don’t just want interactive multimedia over our networks… we want it to be reliable and high-quality • A distributed multimedia system can come to the rescue Docsity.com Definitions • Bandwidth: data rate through a component • Latency: time needed for a packet to travel end to end • Loss rate: acceptable drop-frame ratio • Quality of service management: negotiation and allocation of computing resources Docsity.com Definitions • Flow specification: explicit representation of required resources • Traffic shaping: using buffers at source and destination to smooth data flow • Admission control: allowing or denying client requests based on available resources Docsity.com 1: Sources provide flow spec to main QOS manager through local QOS managers 2: Main QOS ready to reserve resources 3: Client send request to main QOS 4: Main QOS decides if client can be served based on available resources 5: If so, main QOS tells local QOS to allocate resources (if not, client is rejected) 6: Service begins 7: Main QOS and local QOS monitor resource usage / quality, adjust allocated resources if necessary 8: Return to step 4 if new client connects 9: Service ends, resources are freed Controller Features and Structure Client Source Source Source QOS QOS QOS Main QOS Transmission Line (Internet) Docsity.com Significant Points • Distributed multimedia systems exist to guarantee quality of delivery levels • Resource reservation is the key • Additional clients do not degrade system – they can be refused if resources are scarce • Quality guarantees are of paramount importance, whether used for business, entertainment, scientific or health-related applications Docsity.com Summary • Serving multimedia requires strict resource control to maintain quality • Resources consist of bandwidth, latency, and loss rate, among others • Source components declare the resources they need in flow specifications • Quality of service managers negotiate and reserve resources to guarantee quality • Source + flow spec + QOS manage + transmission lines = distributed multimedia system Docsity.com