1. NUS.SOC.CS5248 Ooi Wei Tsang Previously, on CS5248..

2. NUS.SOC.CS5248 Ooi Wei Tsang IP Multicast

3. NUS.SOC.CS5248 Ooi Wei Tsang New Model: IP Multicast sender receivers

4. NUS.SOC.CS5248 Ooi Wei Tsang Question 1 Router G ? should I forward this packet to my subnet?

5. NUS.SOC.CS5248 Ooi Wei Tsang IGMP v2.0 JOIN message A : “I want to join group G.” QUERY message R : “Which group have you joined ?”

6. NUS.SOC.CS5248 Ooi Wei Tsang IGMP v2.0 LEAVE message “I want to leave group G” Group-Specific Query “Anybody else belongs to group G ?”

7. NUS.SOC.CS5248 Ooi Wei Tsang Rate Adaptations

8. NUS.SOC.CS5248 Ooi Wei Tsang Layered Video Layer 1 Layer 2Layer 3

9. NUS.SOC.CS5248 Ooi Wei Tsang TCP-Equation Window size behavior in TCP/IP with constant loss probability T. Ott, J. Kemperman, and M. Mathis June 1997, HPCS 1997

10. NUS.SOC.CS5248 Ooi Wei Tsang Heterogeneity

11. NUS.SOC.CS5248 Ooi Wei Tsang Internet Heterogeneity 2 Mbps 40kbps 56kbps

12. NUS.SOC.CS5248 Ooi Wei Tsang Two Simple Solutions one stream to fit them all send multiple streams

13. NUS.SOC.CS5248 Ooi Wei Tsang Network Encoder Sender Middlebox Receiver Decoder

14. NUS.SOC.CS5248 Ooi Wei Tsang Receiver-Driven Layered Multicast Steve McCanne, Van Jacobson, Martin Vetterli SIGCOMM 1996

15. NUS.SOC.CS5248 Ooi Wei Tsang Layered Multicast 1 Layer : 1 Multicast Group Receiver subscribes to as many layers as desired

16. NUS.SOC.CS5248 Ooi Wei Tsang RLM Example SR1 R2 R3R4

17. NUS.SOC.CS5248 Ooi Wei Tsang Questions How many layers are enough?

18. NUS.SOC.CS5248 Ooi Wei Tsang Solution: Join Experiment highest layer = 1 join layer 1 while no packet loss highest layer ++ join next layer leave highest layer highest layer --

19. NUS.SOC.CS5248 Ooi Wei Tsang Details T join Time between join experiments T detect Time taken to detect packet loss

20. NUS.SOC.CS5248 Ooi Wei Tsang Effects of T join Need to converge to the right level quickly T join should be small Repeated failed experiments congest networks T join should be large

21. NUS.SOC.CS5248 Ooi Wei Tsang Adapting T join (i) One T join per layer if join experiment for layer k fails T join (k) = T join (k)*2

22. NUS.SOC.CS5248 Ooi Wei Tsang Example 1 2 3 4

23. NUS.SOC.CS5248 Ooi Wei Tsang Adapting T detect Set T detect to large initial value Estimate T detect with mean and deviation Measure time between join and packet loss occur

24. NUS.SOC.CS5248 Ooi Wei Tsang Two Problems Interference Scalability

25. NUS.SOC.CS5248 Ooi Wei Tsang Problem 1: Interference

26. NUS.SOC.CS5248 Ooi Wei Tsang Problem 1: Interference I see, layer 2 is bad for me..

27. NUS.SOC.CS5248 Ooi Wei Tsang Problem 2: Scalability Lots of receivers Lots of experiments Lots of congestions

28. NUS.SOC.CS5248 Ooi Wei Tsang Solution: Shared Learning I am joining layer 2, do not disturb!

29. NUS.SOC.CS5248 Ooi Wei Tsang Solution: Shared Learning

30. NUS.SOC.CS5248 Ooi Wei Tsang Solution: Shared Learning I am joining layer 3, do not disturb!

31. NUS.SOC.CS5248 Ooi Wei Tsang Solution: Shared Learning I see, layer 3 is bad for me..

32. NUS.SOC.CS5248 Ooi Wei Tsang Solution: Shared Learning I see, layer 3 is bad for me..

33. NUS.SOC.CS5248 Ooi Wei Tsang Problem Reducing interference decrease convergence time Solution:

34. NUS.SOC.CS5248 Ooi Wei Tsang Evaluation Session Size Convergence Time (s) 20 100 2 40 60

35. NUS.SOC.CS5248 Ooi Wei Tsang Evaluation Loss Rate (%) Session Size 1 100

36. NUS.SOC.CS5248 Ooi Wei Tsang Problems with RLM Not TCP Friendly Share learning is “clumsy” Failed join experiments is bad for the network

37. NUS.SOC.CS5248 Ooi Wei Tsang Thin Streams: An Architecture for Multicasting Layered Video L. Wu, R. Sharma., B. Smith NOSSDAV 97

38. NUS.SOC.CS5248 Ooi Wei Tsang How bad is failed experiment? R: sending rate of a layer T j : IGMP join latency T l : IGMP leave latency T detect : time before drop Buffer space at the router =

39. NUS.SOC.CS5248 Ooi Wei Tsang How big is IGMP Leave Latency?

40. NUS.SOC.CS5248 Ooi Wei Tsang What To Do? Buffer space at the router = R(T j + T l + T detect ) Proposal of ThinStream Reduce R Reduce T detect

41. NUS.SOC.CS5248 Ooi Wei Tsang Reducing T detect Detect congestion before it happens

42. NUS.SOC.CS5248 Ooi Wei Tsang Calculating A & E R: bandwidth of one layer I: measurement interval N: number of bytes received in I G: number of layers joined A = E =

43. NUS.SOC.CS5248 Ooi Wei Tsang ThinStreams Algorithm if (E - A > leave_threshold) leave else if (at least T join since last join) and (E - A < join_threshold) join

44. NUS.SOC.CS5248 Ooi Wei Tsang Fairness Improve fairness leave_threshold as a function of G

45. NUS.SOC.CS5248 Ooi Wei Tsang Problems with ThinStream Small R Still not TCP friendly

46. NUS.SOC.CS5248 Ooi Wei Tsang TCP-Like Congestion Control for Layered Multicast Data Transfer L. Vicisano, J. Crowcroft, L. Rizzo INFOCOM 98

47. NUS.SOC.CS5248 Ooi Wei Tsang The RLC Protocol 1. Try to emulate TCP 2. Synchronize join 3. “Probe” before join

48. NUS.SOC.CS5248 Ooi Wei Tsang Recall TCP’s Behavior AIMD

49. NUS.SOC.CS5248 Ooi Wei Tsang Recall Layered Multicast 1 2 3 4

50. NUS.SOC.CS5248 Ooi Wei Tsang 1. Emulating TCP Idea: By finding appropriate B i and T join (i)

51. NUS.SOC.CS5248 Ooi Wei Tsang Idea 1 2 3 4

52. NUS.SOC.CS5248 Ooi Wei Tsang 2. Synchronizing Join Idea: send special packets in data stream to signal join Distance between synchronization point for layer i is T join (i)

53. NUS.SOC.CS5248 Ooi Wei Tsang Sync Point 1 2 3 4

54. NUS.SOC.CS5248 Ooi Wei Tsang 3. Probe before Join Emulate joining the next layer If this causes packet drop, don’t join

55. NUS.SOC.CS5248 Ooi Wei Tsang Sender-Based Probing base layer i

56. NUS.SOC.CS5248 Ooi Wei Tsang Sender-Based Probing base layer i

57. NUS.SOC.CS5248 Ooi Wei Tsang Problems with RLC Burst too short No fine grain increment

58. NUS.SOC.CS5248 Ooi Wei Tsang Summary Receiver Driven Layered Multicast Lots of Problems No Perfect Solutions