Distributed Multimedia Streaming over Peer-to-Peer Network


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Distributed Multimedia Streaming over Peer-to-Peer Network

  1. 1. Distributed Multimedia Streaming over Peer-to-Peer Network Jin B. Kwon, Heon Y. Yeom Euro-Par 2003, 9th International Conference on Parallel and Distributed Computing, August 2003, (Klagenfurt, Austria) (Also published in LNCS 2790, Euro-Par 2003 Parallel Processing, pp. 851-858)
  2. 2. Agenda <ul><li>Introduction </li></ul><ul><li>Definitions and assumptions </li></ul><ul><li>Transmission Scheduling </li></ul><ul><li>Fast Distribution </li></ul><ul><li>Simulations and Performance Studies </li></ul><ul><li>Conclusion </li></ul>
  3. 3. Introduction <ul><li>Existing multimedia streaming </li></ul><ul><ul><li>Client-sever model </li></ul></ul><ul><ul><li>-> server network bandwidth limitations… </li></ul></ul><ul><li>Possible solutions </li></ul><ul><ul><li>Multicast </li></ul></ul><ul><ul><li>->scalability </li></ul></ul><ul><ul><li>Peer-to-Peer model </li></ul></ul><ul><ul><li>->in early stage </li></ul></ul>
  4. 4. Introduction <ul><li>The authors focus on </li></ul><ul><ul><li>1)Transmission scheduling of the media data for a multi-supplier P2P streaming session </li></ul></ul><ul><ul><ul><li>Supplying peers with heterogeneous out-bound bandwidth </li></ul></ul></ul><ul><ul><ul><li>The problem is to schedule the segments of media data so as to minimize the buffering delay </li></ul></ul></ul><ul><ul><ul><li>Propose Fixed-length slotted scheduling (FSS), better than OTS. </li></ul></ul></ul>
  5. 5. Introduction <ul><li>The authors focus on </li></ul><ul><ul><li>2)Fast distribution of media contents </li></ul></ul><ul><ul><ul><li>P2P system is self-growing. </li></ul></ul></ul><ul><ul><ul><li>Important to convert requesting peer to supplying peers as soon as possible </li></ul></ul></ul><ul><ul><ul><li>Propose FAST : aims at accelerating the speed at which the P2P system capacity increases </li></ul></ul></ul>
  6. 6. Definitions <ul><li>Candidate Set : Set of supplying peers </li></ul><ul><li>Requesting peer </li></ul><ul><ul><li>selects the supplying peers from the set, </li></ul></ul><ul><ul><li>opens a channel with each selected supplying peer, </li></ul></ul><ul><ul><li>requests the data segment from them according to a scheduling mechanism </li></ul></ul><ul><ul><li>After receiving, stores and becomes a candidate of the media content </li></ul></ul>
  7. 7. Assumptions <ul><li>Appropriate searching algorithm </li></ul><ul><li>γ : playback rate of the media data </li></ul><ul><li>P r : requesting peer </li></ul><ul><li>R in (r) : in-bound bandwidth P r </li></ul><ul><li>R out (r) : out-bound bandwidth P r </li></ul><ul><li>0 < R in (r) ≤ γ R out > 0 </li></ul><ul><li>: buffering delay </li></ul>
  8. 8. Transmission Schedule <ul><li>The goal : minimize buffering delay while ensure continuous playback </li></ul><ul><li>Determine the data segments to be transmitted over each channel and the transmission order of the segments. </li></ul>
  9. 9. <ul><li>To ensure continuous playback </li></ul>Amount of consecutive data from the beginning of the media file received for t seconds d(t) Amount of data being played for t seconds since beginning of playback p(t)
  10. 10. OTS <ul><li>Consider 4 channels with bandwidth of </li></ul>
  11. 11. Fixed Length Slotted Scheduling (FSS) <ul><li>Variable-length segments are assigned to the channels in round-robin fashion </li></ul><ul><li>Define slot length w </li></ul><ul><li>i-th channel bandwidth B i </li></ul><ul><li>segment length wB i </li></ul><ul><li>Use previous example, </li></ul>
  12. 12. Fixed Length Slotted Scheduling (FSS) <ul><li>notice the overhead transmission! </li></ul>
  13. 13. Fast Distribution - definition <ul><li>Requesting Peer </li></ul><ul><li>Candidate Peer </li></ul><ul><li>Mature Peer : holding the whole media file </li></ul><ul><li>Immature Peer : being download the media data </li></ul>
  14. 14. Fast Distribution <ul><li>X i (t, r) : when P i is assumed to be selected as a supplying peer of a request peer P r , the position within the media file of the data to be requested to transmit at t. </li></ul>Rate of increase For a immature peer to be a supplying peer of P r (called semi-mature peer)
  15. 15. Fast Distribution <ul><li>X i (t, r) can not be determined until P r select its supplying peers </li></ul><ul><li>use upper bound function x r (t) </li></ul>However, not satisfying it does not mean that P i is not a semi-mature peer
  16. 16. Peer requesting video : procedure <ul><li>Select from mature and semi-mature peers </li></ul><ul><li>Since FSS depends on B 1 , the maximum outbound bandwidth peer will be chosen. The procedure is repeated until B*(r) = R in (r) </li></ul>
  17. 17. Peer requesting video : procedure <ul><li>If the P2P system is beyond capacity </li></ul><ul><ul><li>Start download with the acquired channels and buffering (FAST1) </li></ul></ul><ul><ul><li>Withdraw the request and retry after a randomized second.(FAST2) </li></ul></ul><ul><ul><li>Start download with the acquired channels and retry to acquire the remainder after T minutes.(FAST3) </li></ul></ul>
  18. 18. Simulation <ul><li>Parameters </li></ul><ul><ul><li>50,100 peers, 100 seed peers initial </li></ul></ul><ul><ul><li>Request arrival rate follows Poisson distribution with mean 1/ Θ </li></ul></ul><ul><ul><li>Video length = 60min </li></ul></ul><ul><ul><li>Inbound bandwidth = γ </li></ul></ul><ul><ul><li>Outbound bandwidth : </li></ul></ul><ul><ul><ul><li>Seed peers : γ /2 </li></ul></ul></ul><ul><ul><ul><li>Others : γ /2, γ /4, γ /8 γ /16 : 10%, 10%, 40%, 40% </li></ul></ul></ul>
  19. 19. Performance Study <ul><li>Assume </li></ul><ul><ul><li>Channel bandwidth has one of γ /2, γ /4, γ /8 γ /16 … γ /2 n </li></ul></ul><ul><ul><li>B*(r) = γ </li></ul></ul><ul><ul><li>Time to transmit a segment </li></ul></ul>=>
  20. 20. Conclusion <ul><li>Variable length segment for Transmission Scheduling FSS </li></ul><ul><li>Define semi-mature peer for fast Distribution </li></ul><ul><li>Performance evaluation over OTS and FSS </li></ul>
  21. 21. ~ End ~