1. © Rui Wang Cycle-Oriented Distributed Preconfiguration Ring-like Speed with Mesh-like Capacity for Self-planning Network Restoration 1 Sep. 2009 Rui Wang Department of Electrical Engineering & Computer Science Information Technology & Telecommunications Research Center ResiliNets Research Group The University of Kansas wangrui@ku.edu

2. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration2 Cycle-Oriented Distributed Preconfiguration Abstract Cycle-oriented preconfiguration of spare capacity is a new idea for designing and operating mesh-restorable networks. It aims to attain the capacity-efficiency of a mesh-restorable network, while approaching the speed of self-healing rings. Compare with self- healing rings, the method contributes more failure schemes to the restoration.

3. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration3 Cycle-Oriented Distributed Preconfiguration Outline The concept of Cycle Preconfiguration Optimal Design of p-cycle Restorable Networks Self-organization of the p-cycle state Conclusion

4. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration4 Cycle-Oriented Distributed Preconfiguration The concept of Cycle Preconfiguration The concept of Cycle Preconfiguration Optimal Design of p-cycle Restorable Networks Self-organization of the p-cycle state Conclusion

5. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration5 Cycle-Oriented Distributed Preconfiguration The concept of Cycle Preconfiguration Background -mesh-restorable network -self-healing rings network Motivation -real-time restoration of mesh networks -increase the speed of mesh-based restoration schemes

6. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration6 Cycle-Oriented Distributed Preconfiguration The concept of Cycle Preconfiguration P-cycles: base on the formation of pre-configured cycles - more widely protect the network as a whole - two nodes have real-time cross-connection workload for any failure

7. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration7 Cycle-Oriented Distributed Preconfiguration The concept of Cycle Preconfiguration Fig. a - an example of p-cycle Fig. b - a span on the cycle breaks and the remaining arc restore Fig. c and d - p-cycle can be accessed for restoration of working paths that are not on the cycle [Credit: Grover-Stamatelakis-1998]

8. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration8 Cycle-Oriented Distributed Preconfiguration The concept of Cycle Preconfiguration Comparison of the p-cycle and ring technologies - the speed of rings, with the efficiency of mesh network [Credit: Grover-Stamatelakis-1998]

9. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration9 Cycle-Oriented Distributed Preconfiguration Optimal Design of p-Cycle Restorable Networks The concept of Cycle Preconfiguration Optimal Design of p-Cycle Restorable Networks Self-organization of the p-cycle state Conclusion

10. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration10 Cycle-Oriented Distributed Preconfiguration Optimal Design of p-Cycle Restorable Networks How p-cycle is generated - Linear integer program (IP) is formulated - simple distinct cycles are generated from the network topology - IP generate an optimal p-cycle plan

11. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration11 Cycle-Oriented Distributed Preconfiguration Optimal Design of p-Cycle Restorable Networks Two p-cycle variations are developed and tested -a p-cycle plan within an existing mesh network spare capacity - a fully restorable plan minimizing spare capacity

12. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration12 Excess Sparing - percentage of spare capacity p-cycle design required above the mesh spare capacity design Cycle-Oriented Distributed Preconfiguration Optimal Design of p-Cycle Restorable Networks [Credit: Grover-Stamatelakis-1998]

13. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration13 Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state The concept of Cycle Preconfiguration Optimal Design of p-Cycle Restorable Networks Self-organization of the p-cycle state Conclusion

14. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration14 DCPC (Distributed Cycle PreConfiguration) -an adaption of the statelet processing rules of SHN (Self Healing Network) protocol -deployment and adaptation of the network cycle preconfiguration state Statelet - embedded on each spare link and contains state fields - incoming statelet - outgoing statelet - broadcast through a network - statelet format: index, hopcount, sendnode, numpaths, route Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state

15. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration15 Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state The p-cycle process - each node explores the network for p-cycle candidates - hand off to the next node in order - all nodes show its best found cycle - the competition flood expands through the network - the globally best cycle candidate dominates everywhere - nodes on the p-cycle update pre-plans to exploit the new one - repeat until a complete deployment of p-cycles is built

16. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration16 Two node roles in the DCPC - Cycler: in charge of the cycle-exploration process within the network - Tandem node: mediate the statelet broadcast competition Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state

17. © Rui Wang 1 Sep. 2009 Cycle-oriented distributed preconfiguration 17 The Tandem Node - rules determine what p-cycle candidate the cycler node will discover - a new incoming statelet displace an outgoing statelet - statelets forward to adjacent nodes - from a Cycle node to Cycle node - from a Tandem to Cycle node Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state [Credit: Grover-Stamatelakis-1998]

18. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration18 Statelet’s score: s=(numpaths)/(hopcount) - numpaths: the number of useful paths - hopcount: the number of spans traverse in the statelet’s route Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state

19. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration19 The Cycler Node Role - the cycler places an outgoing statelet on one spare link - the cycler node invests a pre-determined time - the cycler maintains a record of received statelet with the best score - it grows in size as it improves its score Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state [Credit: Grover-Stamatelakis-1998]

20. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration20 Six main regions appear in the plot 10 individual cycler node exploration In the last region no node finds any feasible p-cycle candidates and the protocol terminates Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state [Credit: Grover-Stamatelakis-1998]

21. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration21 DCPC protocol performance assessment The p-cycle restorability levels achievement Trigger a follow-up real-time restoration protocol Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state [Credit: Grover-Stamatelakis-1998]

22. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration22 Cycle-Oriented Distributed Preconfiguration Conclusion The concept of Cycle Preconfiguration Optimal Design of p-Cycle Restorable Networks Self-organization of the p-cycle state Conclusion

23. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration23 Cycle-Oriented Distributed Preconfiguration Conclusion Cycle-oriented preconfiguration of spare capacity is a technological enabler for restoration with the speed of rings while retaining the capacity efficiency of a span restorable mesh network - restoration is performed by simply breaking into these cycles and substituting traffic at failure time - it remains a mesh restoration technology

24. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration24 Acknowledgements Thanks to Prof. James for advice Thanks to ResiliNets group for help

25. © Rui Wang 1 Sep. 2009Cycle-oriented distributed preconfiguration25 Reference [Credit: Grover-Stamatelakis-1998] W.D. Grover and D. Stamatelakis, "Cycle-oriented distributed pre-configuration: ring- like speed with mesh-like capacity for self-planning network restoration", in Proc. IEEE International Conf. Commun. (ICC '98), pp. 537-543, Atlanta, June 8-11, 1998