2. Multicasting Seminar By: Professor A. Hanna Department of Computer Science, Concordia University, Montreal Canada.

3. Multicasting - A Proposal for a General Architecture Aiman Hanna J. William Atwood Department of Computer Science Concordia University Concordia University IEEE International Conference for Telecommunication (ICT-2001) Bucharest, Romania - June 2001

4. Our World Large-scale communication over very high- speed networks. –Defense & Intelligence –Medical Imaging –Education –……. Protocol: A set of rules for guiding communication among a set of participants Slide 3

5. Slide 4 Multicasting Unicasting

6. Slide5 Different Features of Multicasting Reliability Scalability Ordering M-to-N Multicast Late-join and Early-leave Receivers Atomicity

7. Slide6 Reliable Multicasting Delivery time Delivery atomicity –Guaranteed delivery to a member or group of members Delivery order Sender/Receivers perspective What is Reliability?

8. Slide7 Architecture of Multicast Protocols Bi-directional Control Flow Multicast Data Flow Sender Receiver Sender Receiver CA CA - Controlling Agent Flat Structure Hierarchical Structure

9. Slide8 Structure Impact on the Protocol –Ideally, they should be capable of supporting: M-to-N multicast, Ordering Sender-based reliability –However, they are incapable of being: Scalable Flat-Structured Protocols

10. Slide9 –Ideally, they should be capable of supporting: Scalability Receiver-based reliability –However, it is significantly difficult for these protocols to support: Ordering Sender-based reliability M-to-N Multicast Structure Impact on the Protocol Hierarchically-Structured Protocols

11. Slide10 Reliable Multicast Protocols The Tree-Based Multicast Transport Protocol (TMTP) The Scalable Reliable Multicast Protocol (SRM) The Reliable Multicast Transport Protocol (RMTP) The Reliable Adaptive Multicast Protocol (RAMP) The Reliable Multicast Protocol (RMP) The Multicast Transport Protocol (MTP-2) The Local Group Based Multicast Protocol (LGMP) The Xpress Transport Protocol (XTP) Major Reliable Multicast Protocols:

12. Slide11 Too Many Protocols, No Standard! M-to-N Multicast Supported only by: SRM RMTP MTP-2 Guaranteed Reliability Supported only by: TMTP RAMP XTP Scalability Supported only by: TMTP LGMP RMTP Ordering Supported only by: RMP MTP-2 The Reality

13. Slide12 Architecture for Reliable Multicast Protocols New The architecture must provide, and without incurring much overhead on the protocol, nor on the network: –Proper Reliability –Scalability –M-to-N Multicast –Ordering –Ability for: – atomicity, – late-join and early-leave receivers, –…….. Goal: Achieving a standard reliable multicast protocol

14. Slide13 Scalability: –Support as many receivers as the application wishes M-to-N Multicast: –Must be achieved with minimal resource consumption –Practical Consideration: How many senders should a session have? Ordering: –Must be achieved with a full separation between policies and mechanisms Proper Reliability: –When sender-initiated must be used, and –when receiver-initiated must be used

15. Slide14 The Significant Set B D CE F A Master Sender Significant Set Multicast Address FIRST Multicast Transmission

16. Slide15 The Significant Set B D CE F A Master Sender JOIN-REQUEST Unicast Transmission

17. Slide16 The Significant Set A B D CE F Master Sender JOIN-CONFIRM Unicast Transmission

18. Slide17 The Significant Set Significant Set Multicast Address Multicast Transmission A B D CE F Master Sender FIRST

19. Slide18 The Significant Set A B D CE F Master Sender Unicast Transmission Unicast Transmission, Already existing paths JOIN-REQUEST

20. Slide19 The Significant Set A B D CE F Master Sender Unicast Transmission Unicast Transmission, Already existing paths JOIN-CONFIRM

21. Slide20 The Significant Set A B D CE F Master Sender Significant Set Multicast Address

22. Slide21 The Simple Receivers Set Local Group Multicast Address Y X Z W CA Controlling Agent Receiver FIRST Multicast Transmission

23. Slide22 The Simple Receivers Set Unicast Transmission CA Y X Z W Controlling Agent Receiver JOIN-REQUEST

24. Slide23 The Simple Receivers Set Unicast Transmission CA Y X Z W Controlling Agent Receiver JOIN-CONFIRM

25. Slide24 The Simple Receivers Set CA Y X Z W Controlling Agent Local Group Multicast Address Receiver

26. Slide25 The Global Multicast Address One single multicast address All data is sent to this multicast address All senders and receivers listen to that multicast address

27. Slide26 Architecture for Reliable Multicast Protocols New

28. Slide27 Architecture Achievements Absolute Reliability: –Both sender-initiated and receiver-initiated M-to-N Multicasting: –Achieved using: only one multicast address when the number of simple receivers is zero two or multiple multicast addresses when the number of simple receivers is > zero

29. Slide28 Architecture Achievements Scalability: –High-level of scalability as a result of using a hierarchical structure and local error recovery Ordering: –Flexibility from Total Ordering to no ordering –Complete separation between policies and mechanisms

30. Slide29 Disadvantages !! Utilizing One multicast address per local group However, that is not a real weakness! Local error recovery is highly supported Network traffic is significantly reduced Number of local groups is relative to the number of receivers within a session In other words: Achieving high scalability, with more efficient error recovery and reduced network traffic is more advantageous than saving a small number of multicast addresses

31. Slide30 Mapping to Existing Protocols –Relatively easy –Significant Set is an add-on to protocol design and implementation –Many parts of current protocol design/ implementation need not to be changed Mapping to Hierarchically-Structured Protocols

32. Slide31 –More complex as a result of structure conversion from flat to hierarchical one –However, many parts of current design/implementation can be used for the significant set Example: An existing proposal for multi-sender communication for XTP Mapping to Flat-Structured Protocols Mapping to Existing Protocols

33. Slide32 Questions?

34. Slide33 Questions?

35. Slide34 Questions?