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PROMISE A Peer-to-Peer Media Streaming System Using CollectCast CPSC 601.43 Presentation by

PROMISE A Peer-to-Peer Media Streaming System Using CollectCast CPSC 601.43 Presentation by Patrick Wong. Introduction. PROMISE is a P2P media streaming system consisting of several different components. Different components of the PROMISE system include: P2P Substrate

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PROMISE A Peer-to-Peer Media Streaming System Using CollectCast CPSC 601.43 Presentation by

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  1. PROMISEA Peer-to-Peer Media Streaming System Using CollectCast CPSC 601.43 Presentation by Patrick Wong

  2. Introduction • PROMISE is a P2P media streaming system consisting of several different components. • Different components of the PROMISE system include: • P2P Substrate • CollectCast: A P2P service forming the foundation of the PROMISE system. • System was developed by Mohamed Hefeeda, Ahsan Habib, Boyan Botev, Dongyan Xu, Bharat Bhargava from Purdue University.

  3. Peer-to-Peer Substrate • P2P Substrate • Maintains connectivity among peers. • Manages peer membership. • Performs object lookups. • Examples include: • Pastry • Chord

  4. CollectCast Architecture

  5. PROMISE Operation Overview: Receiver Side • Receiver performs a lookup request to the P2P substrate, which returns a set of candidate peers. • An annotated topology of the available peers is created. • Using the topology, the best subset of peers is included into an active set. • The rest of the peers are kept in a standby set. • Receiver establishes two connections (one TCP and one UDP) with each peer in the active set. • Receiver determines sending rate and data assignment for each sender.

  6. PROMISE Operation Overview:Switching & Sender Side Switching: • If a peer failure occurs or the network becomes congested the active set is switched. • During a switch topology is updated and a new active set is selected. Sender Side: • Sender adjusts sending rate and retrieves data assignment from the receiver’s control packets.

  7. CollectCast Architecture

  8. Peer Selection Three peer selection techniques include: • Random Selection • End-to-End • Topology Aware

  9. End-to-End Selection

  10. Topology-Aware Selection

  11. Topology Inference: Introduction • Characterstics that are needed to determine the topology are: • Logical Topology • Available Bandwidth • Loss Rate • Network Tomogrophy Technique • Determining the interior characteristics of a network based on its end-points.

  12. Topography Inference: Logical Topography During the Logical Topography Construction: • All the links are discovered between the senders and receiver. • A traceroute program is used by all peers in parallel to trace the route to the receiver in order to discover all the links.

  13. Topology Inference: Available Bandwidth • One-way Delay Difference (Ddiff) is measured for a periodic packet stream. • If the streaming rate is higher than BW, Ddiff will show an increasing trend. • If streaming rate is lower than BW, Ddiff is 0. • Based on the trend of Ddiff, the stream rate will be increased or decreased by a factor of 2. • A single peer may not be able to send at a high enough rate. Multiple peers are used to simulate the effect of a single peer. • The probe data used to determine BW is the actual data itself.

  14. Topology Inference: Loss Rate • Lost packets are recorded at the same time as measuring the bandwidth (i.e the previous operation) • Lost packets are only recorded on the end-to-end level. • Probabilistic models are needed to infer individual segment losses.

  15. Rate and Data Assignment • Rate assignment refers to the streaming rate of the data and it is proportional to the offered rate of the peer. • Data assignment refers to the number of packets that a peer needs to send to the receiver and it is proportional to the streaming rate. • PROMISE uses a FEC mechanism to tolerate packet losses. • Rate and data assignment are dependent on the loss tolerance of the FEC mechanism. • As the loss tolerance is increased, the rate and data assignment are increased accordingly.

  16. Monitoring and Adaptation • Peer failure is detected using the following two indicators. • TCP control channel • Degraded rate. • Failed peers are replaced with new ones from the standby set. • All the remaining good peers are kept, which is a non-optimal solution.

  17. PROMISE Evaluation • Simulation Experiments • 1000 candidate peers and 600 routers. • All 3 peer selection techniques were used: random, end-to-end, and topology aware. • Peer failures were simulated as well. • Internet Experiments • Six candidate peers across North America and Europe. • Four peers are included in the active set and two peers are replaced during the simulation.

  18. Received Rate Comparison between Different Peer Selection Techniques

  19. Summary • PROMISE is a P2P system designed to work on top of a service called CollectCast. • Three peer selection techniques are available: random, end-to-end, topology-aware. • Topology inference technique is used to determine the best set of peers. • Both simulation and Internet experiments were conducted using PROMISE.

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