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Protocols

Protocols. You are Here. Encoder. Decoder. Middlebox. Receiver. Sender. Network. Interested ISO Layers. Application. Transport. Network. Interested ISO Layers. RTP. TCP. UDP. Network. IP Multicast. IP. IP Multicast. Communication Models. sender. receiver.

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Protocols

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  1. Protocols

  2. You are Here Encoder Decoder Middlebox Receiver Sender Network

  3. Interested ISO Layers Application Transport Network

  4. Interested ISO Layers RTP TCP UDP Network IP Multicast IP

  5. IP Multicast

  6. Communication Models sender receiver Traditional Applications: One-to-One

  7. Communication Models sender receivers Media Applications: One-to-Many

  8. Communication Models Media Applications: Many-to-Many

  9. Naïve Solution • Create M unicast connection for M clients NOT Scalable!

  10. Famous Example • Victoria’s Secret Spring Fashion Show • Live Broadcast in 1999 • Video bit-rate: 28 Kbps • Number of viewers: 1.5 Millions

  11. New Model: IP Multicast sender receivers

  12. Group and Members members

  13. Sending to a Group

  14. Joining and Leaving

  15. Anyone can Send

  16. Multicast Address • Group ID or “Multicast address” • 224.0.0.0 – 239.255.255.255

  17. Unicast S A A B Router C B Router Router Router C

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

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

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

  21. Question 1 should I forward this packet to my subnet? Router ? G

  22. Question 2 which neighbors should I forward this packet to? Router Router Router Router

  23. GroupManagement

  24. Group Management • Routers maintain “local host group membership table” • “which group has a member in my subnet ?”

  25. IGMP v2.0 Internet Group Management Protocol • JOIN messageA : “I want to join group G.” • QUERY messageR : “Which group have you joined ?”

  26. IGMP v2.0 • LEAVE message“I want to leave group G” • Group-Specific Query“Anybody else belongs to group G ?”

  27. IGMP v2.0 • MEMBERSHIP ReportA : “I am a member of group G”A : “I am a member of group H”B : “I am a member of group G”

  28. Question 2 which neighbors should I forward this packet? Router Router Router Router

  29. RoutingProtocols

  30. Routing Protocols • Generic Methods : • Form a tree to all routers with members • Deliver the packets along the tree

  31. Shortest Path Tree • One tree for each source for each group

  32. Shared Tree • One tree for each group

  33. Routing Protocols • DVMRP – shortest path tree • CBT – shared tree • PIM – combine both

  34. DVMRP Distance Vector Multicast Routing Protocol

  35. From S to G S : Q R P T

  36. Is R on the shortest path to S ? S : Q R P T

  37. If no.. ignore the packet Q R P T

  38. If yes.. Where should I forward it to ? Q R P T

  39. Is my subnet interested? Q R P T

  40. Are my neighbors interested? Q ? R P T ?

  41. Observation • If neighbor is going to ignore my packets, don’t need to send the packets to it.

  42. Exchanging Routing Tables Q R P T

  43. Flooding • Default : Always send to neighboring routers, unless told otherwise.

  44. Pruning • Routers who received a “useless” packet send a prune message back.“Don’t send me packets addressed to G anymore !”

  45. Q R P T

  46. Q R P T PRUNE

  47. Q R P T

  48. Q R P T GRAFT

  49. Q R P T

  50. Q PRUNE R P T

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