1. Improving Individual Flow Performance with Multiple Queue Fair Queuing Author: Manfred Georg, Christoph Jechlitschek, Sergey Gorinsky Publisher: Quality of Service, 2007 Fifteenth IEEE International Workshop on Presenter: Chun-Yi Li Date: 2008/10/29

2. 2 Overview  Previous Work Protecting Flow Performance Fair Queuing Stochastic Fair Queuing (SFQ)  Multiple Queue Fair Queuing Introduction Deficit Round Robin Avoid Reordering  Performance

3. 3 Protecting Flow Performance  Per-Flow Fair Queuing Poor scalability  Aggregate Fair Queuing (SFQ, SFB) ‏ No protection within aggregate  Identify and Limit (CHOKe, AFD) ‏ Delayed reaction Difficult to detect some flows  Multiple Queue Fair Queuing (MQFQ) ‏ Per-aggregate fair queuing with backup queue for each flow

4. 4 Fair Queuing  Each Flow Has Different Queue Serve queues independently Incoming Packets Outgoing Packets Flow 1 Flow 3 Flow 2

5. 5 1 Stochastic Fair Queuing  Fixed Number of Queues Hash function maps flow to queue Blue Orange Gray Green Hash Function 1 2 4 2 3 11 22 33 22 44 11 Flow 1 and 3 Interfere

6. 6 Multiple Queue Fair Queuing (MQFQ) ‏  Fixed Number of Queues  Two Hash Functions  Protection of Individual Flows in Aggregate Queuing  Surrender Some Capacity to Misbehavers  No Packet Reordering Within Flow

7. 7 1 1 2 3 1 1 1 1 2 Multiple Queue Fair Queuing (MQFQ) ‏  Two Hash Functions Place packet in queue with fastest service Avoid misbehavior Blue Orange Gray Green Hash Function 1 Hash Function 2 1 1 1 1 1 1 2 2 2 Quantum Partial Interference Between Flows 1 and 2 3 3 3 1 1 1 1 1 1 4 4 4 Complete Interference Between Flows 1 and 4

8. 8 Deficit Round Robin  Each Queue Maintains a Deficit Quantum added to deficit and then spent Outgoing Link Quantum Blue Orange Gray Green 1 2 4 2 33 1242

9. 9 Probability of Flow Interference MQFQ Partial MQFQ Complete SFQ Complete (k)‏

10. 10 Avoid Reordering  MQFQ Can Reorder Different Length Packets by at Most One Round  Split Packets Into Constant Sized Cells All packets have same possibilities Cells generally used in multi-stage switches 1 1111 1

11. 11 50 TCP Flows

12. 12 49 TCP flows + Misbehaving CBR

13. 13 50 CBR Flows

14. 14 Many Hash Functions (TCP Flows) ‏