1. Quality of Service Based Routing Ziv Kedem

2. Introduction n QoS Routing can improve network performance n The price is an increase in protocol and computational complexity n Stale link information can degrade network performance

3. QoS Routing Free Busy Very Busy

4. Stale Link Information

5. Topics of Discussion n Different routing policies n Protocol overhead n Performance analysis n Processing cost n Improvements

6. Different Routing Policies n Static / dynamic routing n Clamp-down timer n Quantization of values n Pruning / no pruning

7. Protocol Overhead n Large value of clamp-down timer can decrease overhead n Overhead can be similar to OSPF n Quantization has little effect on the number of updates

8. Protocol Overhead

9. Performance Analysis n Large values of clamp-down timer n Comparison with static QoS routing n Non-pruning policies are more stable n Quantization introduces ties

10. Performance Analysis

11. Improvements n Randomization u Depends on length and width u Useful in hot-spot traffic n Hybrid solution u Long lived flows are more stable u No need for explicit flow request

12. Randomization

13. Improvements n Randomization u Depends on length and width u Useful in hot-spot traffic n Hybrid solution u Long lived flows are more stable u No need for explicit flow request

14. Hybrid Solution

15. Processing Cost n Calculation for each flow request is expensive n Pre-computation u Periodic u On each update

16. Processing Cost

17. Conclusions n QoS routing can improve network performance n Large clamp down timer is necessary n Stale link information requires use of stable policies n Randomization / hybrid solutions can improve performance