MQ：An Integrated Mechanism for Multimedia Multicasting

1. MQ：An Integrated Mechanism for Multimedia Multicasting De-Nian Yang, Wanjiun Liao, Member, IEEE, and Yen-Ting Lin IEEE TRANSACTIONS ON MULTIMEDIA VOL. 3, NO. 1, MARCH 2001

2. Outline • Introduction • RSVP with SPM、QoSM • MQ：Multicast with QoS • Tree Construction • Tree Maintenance • Tree Pruning • Tree Reshaping • Loop Free Control • QoS Metrics • Performance Evaluation • Conclusions

3. Introduction • Multicast：A packet contains a class D group address in the destination address field of its IP header. • Quality-of-Service (QoS)：A bound on delay、jitter、loss ratio or bandwidth

4. Introduction • QoS routing： • Determine a feasible path which satisfies the QoS constraint of a data flow (source) • Make efficient use of network resources • Resource reservation for QoS： • Sender-oriented • Receiver-oriented：RSVP

5. RSVP (ReSerVation Protocol) RSVP Daemon Policy Control Admission Control Application Data Packet Classifier Packet Scheduler

6. Reservation request merges as it travels up the multicast tree. Sender Path Resv Path Path Resv Resv Receiver#1 Receiver#2 Receiver#3 RSVP (ReSerVation Protocol)

7. Path Path Fail RSVP with Shortest Path Multicast MOSPF：

8. Path Path Fail RSVP with QoS Multicast Routing QOSPF：

9. MQ：Tree Construction • The sender multicasts Flow_Ad message through the shortest path delivery tree to all flow recipients. • The receiver sends a Join_Request message back, and it travels upstream only as far as the closest point of the delivery tree where the requested reservation is met, from where a Join_Ack message is returned.

10. MQ：Tree Construction • The breakout router, the router which is insufficient to meet the requested QoS, uses QoS routing to determine a new feasible path. • If such a path is found, the router forwards the request toward the new path and waits for an acknowledgement; otherwise returns a Join_Fail message. • Upon receiving a Join_Fail message, the router acts as a breakout router, using QoS routing to determine a path.

11. MQ：Tree Construction • This operation repeats until : • An on-tree router located at the joining path has found a path based on QoS routing and has received a Join_Ack from the new path. • All the on-tree routers have failed to find a path, causing the recipient to receive a Join_Fail. • Upon receiving a Join_Ack, the breakout router • Forwards the Join_Ack downstream, and • Sends a ResvRev (reservation remove) message upstream in the old path to relinquish resources.

12. Flow_Ad Join_Request(1) Join_ Ack(2) Join_Ack(2) Flow_Ad Join_Request(1) Join_Request(1) Join_Ack(2) Join_Ack(2) Join_Request(1) MQ：Tree Construction

13. Join_ Request (1) Join_Ack (2) MQ：Tree Construction

14. Join_Ack (2) Join_ Request (1) Join_Fail (2) ResvRev (3) Join_ Request (1) Join_ Request (1) Join_Ack (2) Join_Ack (2) Join_ Request (1) MQ：Tree Construction

15. MQ：Tree Maintenance • Flow_Ad：Sent by a source on three occasions • Periodic distribution • Whenever there is a change in the source • And per request (Flow_Solicit) • Refresh：Sent by a receiver periodically • To keep reservation alive (TearDown) • To request a change in QoS

16. Shrink Shrink ResvRev MQ：Tree Pruning

17. MQ：Tree Reshaping • 1. Employs QoS routing with the maximum reserved bandwidth among all the downstream as the QoS metric to determine a feasible path. • 2. Sends an Off_Tree_Query to the new path. The hob count field of the message is incremented by one whenever a router is traversed. The on-tree router receives the message and responds with an Off_Tree_Reply of which the hob count field is copied from the Off_Tree_Query when QoS metric satisfied, or set to infinity otherwise.

18. MQ：Tree Reshaping • 3. Sends an On_Tree_Query message which travels upstream along the multicast tree until reaching an on-tree router with more than one downstream interface, from where an On_Tree_Reply with a copy of the hob count of the On_Tree_Query is returned. • 4. Upon receipt of both returned messages, the reshaping router compares the hob count values. Only when the Off_Tree_Reply is smaller will the tree be reshaped by using Join_Request、Join_Ack and ResvRev messages.

19. On_Tree_Query ResvRev On_Tree_Reply Off_Tree_Reply Join_Ack Off_Tree_Query Join_ Request On_Tree_Query ResvRev On_Tree_Reply MQ：Tree Reshaping

20. Join_Request ResvRev Join_Fail Join_Request ResvRev Join_Fail Join_Request Join_Ack Join_Ack Join_ Request Join_Request Join_Ack Join_Fail ResvRev Join_ Request ResvRev Join_Fail Join_ Request MQ：Loop-Free Control

21. R2 Succeed R4 Fail !! R3 Succeed R1 Succeed 1.5 Mbps 70ms R2 Fail!! (1.5,30) (1.5,20) 40ms 1.0 Mbps 100ms 80ms 100ms 1.5 Mbps 120ms 120ms MQ：QoS Metrics

22. Simulation Setup Flat graph model with 100 nodes Hierarchical graph model with 100 nodes

23. Simulation Setup • For an edge between pairs of nodes (u,v), the edge probability is given： P(u,v)=β*exp(-d(u,v)/αL), where 0< α,β≦1 and d(u,v) is the Euclidean distance from u to v. • α↑ : (no. of connections of distant nodes)↑ • β↑ : (the edge densities)↑ • We use (α,β)=(0.2,0.2) here.

24. Performance Metrics • We compare： • 1. RSVP with SPM：MOSPF (hob count) • 2. RSVP with QoSM：QOSPF (hob count, bandwidth) • 3. MQ： (hob count, bandwidth) • We measure： • 1. Blocking Probability • 2. Protocol Overhead • 3. Resource Utilization

25. Blocking Probability

26. Resource Utilization

27. Overhead Comparison

28. Conclusions • Being a truly receiver-initiated, soft state, and integrated scheme for multicast QoS services, MQ demonstrates • 1. lower blocking probability for users to join the group of interest with requested QoS, • 2. much reduced protocol overhead, and • 3. more efficient resource utilization, as compared to traditional approaches.