C O R P O R A T E T E C H N O L O G Y Strategies for Enhanced Dual Failure Restorability with Static or Reconfigurable p-Cycle Networks International Conference on Communications (ICC) Paris, France - June 22, 2004 Dominic A. Schupke* Siemens AG, Corporate Technology Otto-Hahn-Ring 6, Munich, Germany Wayne D. Grover, Matthieu Clouqueur TRLabs and University of Alberta 7th Floor, St NW, Edmonton, Alberta, Canada T6G 2V4 *Results from work at Technische Universität München and TRLabs

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Outline Introduction The p-Cycle Concept p-Cycles and Dual Failures Network Design Results Conclusions

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Introduction Preconfigured protection cycles (“p-cycles”): Applicable in many kinds of networks High capacity-efficiency Fast protection switching times For span-protection: 100% restorability against any single span failure Our focus: Provide enhanced or optimized level of dual-failure restorability Static and reconfigurable p-cycles

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, The p-Cycle Concept A p-cycle in a mesh network: D A B E C

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, The p-Cycle Concept On-cycle link failure: D A B E C

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, The p-Cycle Concept Straddling link failure: D A B E C Straddling link Path 1

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, The p-Cycle Concept Straddling link failure: D A B E C Path 2

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Assumptions on Dual Failures Dual failure scenarios: Assumption: t 1 + t 1,rec. < t 2 p-Cycles: t rec. ~ 50 ms t1t1 t 1 +t 1,rec. t2t2 First (span) failure Recovery from first failure Second failure t 2 +t 2,rec. t 2 +t 2,rep. t 1 +t 1,rep. Recovery from second failure (if possible) Repair of first failure Repair of second failure

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Static p-Cycles and Dual Failures D A B E C t1t1

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Static p-Cycles and Dual Failures D A B E C  No recovery for B-C from second failure t1t1 t2t2

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Static p-Cycles and Dual Failures D A B E C t1t1 p -Cycle A p -Cycle B

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Static p-Cycles and Dual Failures D A B E C  Recovery from second failure t1t1 t2t2 p -Cycle A p -Cycle B

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Susceptibility Concept p-Cycle susceptible to a dual failure combination: Both failures affect working spans protected by it p-Cycle protects s working spans  Susceptible to s (s-1) failure events Susceptibility s per p-cycle not larger than given σ max Restrict when selecting eligible p-cycles for design Other approach: Failure dispersal concept (see paper)

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Reconfigurable p-Cycles and Dual Failures D A B E C t1t1

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Reconfigurable p-Cycles and Dual Failures D A B E C t1t1 Vulnerable protection capacity

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Reconfigurable p-Cycles and Dual Failures D A B E C t1t1 Vulnerable working capacity

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Reconfigurable p-Cycles and Dual Failures D A B E C t1t1 p -Cycle formed - after t 1

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Reconfigurable p-Cycles and Dual Failures D A B E C  Recovery from second failure t1t1 t2t2 p -Cycle formed - after t 1 and - before t 2

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Network Design Cost-optimal design: Length-weighted utilization of network Single-failure restorability: 100% restorability guaranteed Dual-failure restorability: R(i,j): Restorable fraction of affected working capacity after dual failure of spans i and j R 2 : Average over all dual failure cases

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Network Design

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, COST239 Case Study Network Hypothetical pan-European optical network of COST239 project Traffic matrix modified to lightpath entries Average nodal degree: d av = 4.7 Three-connected (connected after any dual span failure)

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Results for Static p-Cycles Dual failure Restorability Additional Relative Spare Capacity Cost Reconfiguration σ max =4 σ max =13 σ max =9 smaller σ max

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Results for Reconfigurable p-Cycles Relative Spare Capacity Cost Static Reconfiguration R 2 =100% Vulnerable working capacity protected only Fraction of p-cycles changeable in form Only additional p-cycles 100%5%0%

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Conclusions Capacity design methods: Static p-cycles: Improved dual-failure restorability Susceptibility viable approach to control restorability Reconfigurable p-cycles: Complete dual-failure restorability Different operational options Outlook: Reconfigurable p-cycles in networks designed for single-failure restorability only Multiple protection classes

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Literature Schupke, D.A.; Grover, W.D.; Clouqueur, M., "Strategies for Enhanced Dual Failure Restorability with Static or Reconfigurable p-Cycle Networks," IEEE International Conference on Communications (ICC), Paris, France, June 20-24, Schupke, D.A., "An ILP for Optimal p-Cycle Selection without Cycle Enumeration," Eighth Working Conference on Optical Network Design and Modelling (ONDM), Ghent, Belgium, February 2-4, Schupke, D.A.; Scheffel, M.C.; Grover, W.D.,"Configuration of p-Cycles in WDM Networks with Partial Wavelength Conversion," Photonic Network Communications, Kluwer Academic Publishers, vol. 6, no. 3, pp , November Schupke, D.A.; Jaeger, M.; Huelsermann, R., "Comparison of Resilience Mechanisms for Dynamic Services in Intelligent Optical Networks," Fourth International Workshop on the Design of Reliable Communication Networks (DRCN), Banff, Alberta, Canada, October 19-22, Schupke, D.A.; Scheffel, M.C.; Grover W.D., "An Efficient Strategy for Wavelength Conversion in WDM p- Cycle Networks," Fourth International Workshop on the Design of Reliable Communication Networks (DRCN), Banff, Alberta, Canada, October 19-22, Kodian, A.; Grover, W.D.; Slevinsky, J.; Moore, D., "Ring-Mining to p-Cycles as a Target Architecture: Riding Demand Growth into Network Efficiency," to appear in Proceedings of the 19th Annual National Fiber Optics Engineers Conference (NFOEC 2003), Orlando, FL, 7-11 September Schupke, D.A., "Multiple Failure Survivability in WDM Networks with p-Cycles," Invited Paper, IEEE International Symposium on Circuits and Systems (ISCAS), Bangkok, Thailand, May 25-28, Shen, G.; Grover, W.D., "Extending the p-Cycle Concept to Path-Segment Protection," Proc. IEEE International Conference on Communications (ICC 2003), Anchorage, AK, USA, May 11-15, 2003, Session ON3. Schupke, D.A., "The Tradeoff Between the Number of Deployed p-Cycles and the Survivability to Dual Fiber Duct Failures," IEEE International Conference on Communications (ICC), Anchorage, AK, USA, May 11-15, 2003.

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Literature Grover, W.D. "p-Cycles, Ring-Mesh Hybrids and "Ring-Mining:” Options for New and Evolving Optical Networks," Invited Paper, Proc. Optical Fiber Communications Conference (OFC 2003), Atlanta, March , 2003, pp Grover, W.D. "Understanding p-Cycles, Enhanced Rings, and Oriented Cycle Covers" (invited paper), 1st Int’l Conference on Optical Communications and Networks (ICOCN’02), Singapore, Nov.11-14, 2002, pp Jaeger, M.; Huelsermann, R.; Schupke, D.A.; Sedlak, R., "Evaluation of Novel Resilience Schemes in Dynamic Optical Transport Networks,“ SPIE Conference Asia-Pacific Optical and Wireless Communications (APOC), Shanghai, China, October 14-18, Schupke, D.A., "Fast and Efficient WDM Network Protection Using p-Cycles," TransiNet Workshop, Berlin, Germany, October 8, Grover, W:D.; Doucette, J. E., "Advances in Optical Network Design with p-Cycles: Joint optimization and pre-selection of candidate p-cycles," Proceedings of the IEEE-LEOS Summer Topical Meeting on All Optical Networking, Mont Tremblant, Quebec, July 15-17, Schupke, D.A., "Fast and Efficient WDM Network Protection Using p-Cycles," Invited Paper, IEEE LEOS Summer Topical Meeting, Mont Tremblant, Canada, July 15-17, Gruber, C.G.; Schupke, D.A., "Capacity-efficient Planning of Resilient Networks with p-Cycles," Networks 2002, 10th International Telecommunication Network Strategy and Planning Symposium, Munich, Germany, June 23-27, Grover, W:D.; Doucette, J. E.; Clouqueur, M.; Leung, D.; Stamatelakis, D."New Options and Insights for Survivable Transport Networks," IEEE Communications Magazine, vol.40, no.1, January 2002, pp Schupke, D.A.; Grover, W.D.; Gruber, C.G.; Stamatelakis, D., "p-Cycles: Network Protection with Ring-speed and Mesh-efficiency,“ Invited Talk, 1 st COST270 Workshop on Reliability of Optical Networks, Systems and Components, Dubendorf, Switzerland, December 12-13, 2001.

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Literature Schupke, D.A.; Autenrieth, A.; Fischer, T., "Survivability of Multiple Fiber Duct Failures," Third International Workshop on the Design of Reliable Communication Networks (DRCN), Budapest, Hungary, October 7-10, Grover, W.D.; Stamatelakis, D., “Bridging the ring-mesh dichotomy with p-cycles,” Second International Workshop on the Design of Reliable Communication Networks (DRCN), Munich, Germany, April , Grover, W.D.; Stamatelakis, D., "IP Layer Restoration and Network Planning Based on Virtual Protection Cycles," IEEE JSAC Special Issue on Protocols and Architectures for Next Generation Optical WDM Networks, vol.18, no.10, October, 2000, pp Grover, W.D.; Stamatelakis, D., "Theoretical Underpinnings for the Efficiency of Restorable Networks Using Pre-configured Cycles ("p-cycles")," IEEE Transactions on Communications, vol.48, no.8, August 2000, pp Grover, W.D.; Stamatelakis, D., "Rapid Restoration of Internet Protocol Networks using Pre-configured Protection Cycles," Proc. 3rd Can. Conf. On Broadband Research (CCBR'99), Nov. 7-9, Ottawa, 1999, pp Grover, W.D.; Stamatelakis, D., "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), Atlanta, June 8-11, 1998, pp

C O R P O R A T E T E C H N O L O G Y © TRLabs / University of Alberta and Siemens AG, CT IC 2 ON, Dominic Schupke, Network Design Assumptions: Dual-failure scenario: Subsequent failures at t 1 and t 2 (with t 2 < t 1 + t repair ) Second failure occurs after completion of recovery of first failure: t 2 > t 1 + t recovery (p-cycles: t recovery ~ 50 ms)