1 Sep. 2009

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

2. 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 . Cycle-oriented distributed preconfiguration

3. 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 Cycle-oriented distributed preconfiguration

4. 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 Cycle-oriented distributed preconfiguration

5. 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 Cycle-oriented distributed preconfiguration

6. 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 Cycle-oriented distributed preconfiguration

7. 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] Cycle-oriented distributed preconfiguration

8. 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] Cycle-oriented distributed preconfiguration

9. 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 Cycle-oriented distributed preconfiguration

10. 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 Cycle-oriented distributed preconfiguration

11. 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 Cycle-oriented distributed preconfiguration

12. Cycle-Oriented Distributed Preconfiguration Optimal Design of p-Cycle Restorable Networks • Excess Sparing - percentage of spare capacity p-cycle design required above the mesh spare capacity design [Credit: Grover-Stamatelakis-1998] Cycle-oriented distributed preconfiguration

13. 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 Cycle-oriented distributed preconfiguration

14. Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state • 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

15. 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 Cycle-oriented distributed preconfiguration

16. Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state • 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

17. Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state • 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 [Credit: Grover-Stamatelakis-1998] Cycle-oriented distributed preconfiguration

18. Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state • 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

19. Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state • 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 [Credit: Grover-Stamatelakis-1998] Cycle-oriented distributed preconfiguration

20. Cycle-Oriented Distributed Preconfiguration Self-organization of the p-cycle state • 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 [Credit: Grover-Stamatelakis-1998] Cycle-oriented distributed preconfiguration

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

22. 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 Cycle-oriented distributed preconfiguration

23. 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 Cycle-oriented distributed preconfiguration

24. Acknowledgements • Thanks to Prof. James for advice • Thanks to ResiliNets group for help Cycle-oriented distributed preconfiguration

25. 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 Cycle-oriented distributed preconfiguration