1 / 83

Course Matters

Explore the challenges and solutions in implementing application-level multicast networks, covering topics such as overlay networks, end-system multicast, mesh construction, optimization, and tree building. Delve into protocols, maintenance, scaling issues, and resource management.

rayfordl
Download Presentation

Course Matters

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Course Matters

  2. Deadlines • 11 Oct: Survey Paper Due • 18 Oct: Paper Reviews Due

  3. Reminder • No lecture next week • Make-up lecture • 23rd October 2004, Saturday • 1-3pm

  4. Previously, on CS5248..

  5. New Model: IP Multicast sender receivers

  6. Multicast S G A Router B Router Router Router C

  7. Multicast S A Router G B Router Router Router G C

  8. Multicast S G A Router B Router Router G Router C

  9. So, why can’t we multicast? • Who assign multicast address? • Who pay for multicast traffic? • How to inter-operate between protocols? • How can we prevent DoS?

  10. Application-Level Multicast

  11. You are Here Encoder Decoder Middlebox Receiver Sender Network

  12. Application-Level Multicast S A A Router B Router Router Router C

  13. Application-Level Multicast S B C A Router B Router Router Router C

  14. Overlay Network S A B C

  15. Penalty: Delay S A Router B Router Router Router C

  16. Penalty: Network Resource S A Router B Router Router Router C

  17. Link Stress S A Router B Router Router Router C

  18. Questions • How to construct overlay multicast tree? • How to maintain overlay multicast tree?

  19. A Case for End-System Multicast Y. Chu, S. Rao, S. Seshan, H. Zhang JSAC 2002

  20. Narada’s Idea • Build a mesh, then build a tree S S A A B C B C

  21. Why Build Mesh?

  22. Desirable Property of Mesh • Path between any two nodes must be “good” • Cannot be too sparse or too dense

  23. How to build Mesh? • Node join • Randomly choose some existing members as neighbour S A B C

  24. How to maintain Mesh? • Everybody knows everybody • Each node maintains a table

  25. How to update table? • Refresh messages • Exchange of tables

  26. How to maintain Mesh? • Node failure • Probes if no refresh messages for a while S A B C

  27. How to maintain Mesh? • Mesh Partition • Probes if no refresh messages for a while, add random edges if alive S A B C

  28. How to Optimize Mesh? • Mesh needs to periodically updated because: • nodes join and leave • network condition changes • partition repair add unneeded edges • initial constructions are random

  29. Adding a Link • Node i periodically probe randomly selected members j • Ask “what if I add (i,j)?”

  30. Adding a Link S S A A B C B C

  31. Removing a Link • Harder to ask “what if I remove link (i,j)?” • compute cost(i,j) instead: number of nodes for which i uses j as next hop

  32. cost(i,j) cost(S,A) = 2 S A B C

  33. cost(i,j) cost(S,A) = 3 cost(A,S) = 1 E S A D B C

  34. Removing a link • if max(cost(i,j), cost(j,i)) < Threshold drop (i,j) (Threshold should depends on group size)

  35. Narada’s Idea • Build a mesh, then build a tree S S A A B C B C

  36. How to build tree? • Modify DVMRP • Cost definition • Pick widest path • Break ties by latency

  37. Evaluation: Bandwidth

  38. Evaluation: RTT

  39. Evaluation: Link Stress

  40. Evaluation: Resource Usage

  41. Scalable Application Layer Multicast S. Banerjee, B. Bhattacharjee, and C. Kommareddy SIGCOMM 2002

  42. Problem • Narada does not scale • State maintenance • Message overhead

  43. NICE • NICE is scalable • State maintenance • Message overhead

  44. Members

  45. Clusters

  46. Leader

  47. Layer

  48. Nodes per Cluster [k, 3k-1]

  49. Control Topology

  50. Multicast Tree

More Related