This slides is for the presentation in conference CPScom 2012.

1. Performance Enhancement and Optimized
Analysis
of the Worst Case End-to-End Delay for AFDX
Networks
Jian Li, HaiBing Guan, JianGuo Yao ,
Shanghai Jiao Tong University, Shanghai, China
Guchuan Zhu
Ecole Polytechnique de Montreal, Canada
and Xue Liu
McGill University, Canada

2. Agenda
• Introduction
• AFDX traffic and service model
• End-to-end delay with GCRA model
• End-to-end delay analysis for FP-RR scheduling
• Simulation
• Conclusion

3. Introduction
• What is AFDX?
– Avionics Full Duplex Switched Ethernet (AFDX)
deals with the problems multiplexing huge
number of communication flows over a full duplex
switched Ethernet network.

4. Introduction

5. Introduction
• the context and the entities of AFDX networks
– Virtual Link
– End System Model
• End System is at the AFDX network boundary in support
of avionics applications accessing the network
– Switch Model

6. Introduction
• the context and the entities of AFDX networks
– Virtual Link
– End System Model

7. Introduction
• the context and the entities of AFDX networks
– Virtual Link
– End System Model
– Switch Model
• The AFDX Switch is responsible for receiving and
forwarding VL packets

8. Introduction
• the context and the entities of AFDX networks
– Virtual Link
– End System Model
– Switch Model

9. Introduction
• End-to-end delay is of a primary concern for AFDX
network because of large latency and jitter.
– The traditional AFDX traffic model, the leaky-bucket
model(σ,ρ) , is not accurate.
– The current switching architecture is not suitable for
various traffic’s priorities with real-time performance
requirement in future.
• Development of solution for tightening the
estimates of e2e transmission delay in AFDX
networks by new model.

10. Agenda
• Introduction
• AFDX traffic and service model
• End-to-end delay with GCRA model
• End-to-end delay analysis for FP-RR scheduling
• Simulation
• Conclusion

11. AFDX traffic and service model

12. AFDX traffic and service model

13. AFDX traffic and service model
• Network Calculus Representation of AFDX
– Because of “Pay Burst Only Once” in Network
Calculus. We can get

14. AFDX traffic and service model

15. AFDX traffic and service model

16. AFDX traffic and service model

17. Agenda
• Introduction
• AFDX traffic and service model
• End-to-end delay with GCRA model
• End-to-end delay analysis for FP-RR scheduling
• Simulation
• Conclusion

18. End-to-end delay with GCRA model
• Single Hop Delay Bound Analysis
– The scheduler adopts a Round-Robin policy to
share the transmission capacity among VLs.

19. End-to-end delay with GCRA model

20. End-to-end delay with GCRA model

21. End-to-end delay with GCRA model

22. Agenda
• Introduction
• AFDX traffic and service model
• End-to-end delay with GCRA model
• End-to-end delay analysis for FP-RR scheduling
• Simulation
• Conclusion

23. End-to-end delay analysis for FP-RR
scheduling
• Single Hop Delay Bound Analysis
– FP-RR: all the VLs with the same priority are treated as
an aggregated flow and use Round Robin policy
he

24. End-to-end delay analysis for FP-RR
scheduling
– Just like RR scheduling’s analysis , we can get the
e2e delay in GCRA model

25. End-to-end delay analysis for FP-RR
scheduling
• Multi-Hop E2E Delay Analysis

26. Agenda
• Introduction
• AFDX traffic and service model
• End-to-end delay with GCRA model
• End-to-end delay analysis for FP-RR scheduling
• Simulation
• Conclusion

27. Simulation
• Platform: TrueTime based on Matlab/Simulink
• AFDX network architecture

28. Simulation
• VL configuration
• bandwidth of the network is 100Mb/s

29. Simulation
• The e2e delay with different VL model

30. Simulation
• The e2e delay with FP-RR

31. Simulation
• The e2e delay with FP-RR(ES) and RR(Switch)

32. Simulation
• VL2 and VL10 delay with FP-RR(ES) and R-R(Switch)
–
–
–

33. Agenda
• Introduction
• AFDX traffic and service model
• End-to-end delay with GCRA model
• End-to-end delay analysis for FP-RR scheduling
• Simulation
• Conclusion

34. Conclusion
• presents a new method for estimating the e2e
delay in AFDX networks based on Network
Calculus.
• Evaluate the worst case e2e delay when
Round-Robin is applied. And show a tighter
upper bound in GCRA model.
• development of a new scheduling policy (FP-
RR) for ESs and Switches which can get a
better e2e delay.

35. Thank you