1. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 1 Benefits of p-Cycles in a Mixed Protection and Restoration Approach François Blouin, Anthony Sack, Wayne D. Grover, Hadi Nasrallah Fourth International Workshop on the Design of Reliable Communication Networks (DRCN 2003) 19-22 October 2003 - Banff, Alberta, Canada October 21, 2003

2. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 2 Introduction Multiple protection and restoration methods may co-exist in optical mesh networks – Automatic protection switching (APS), shared backup path protection (SBPP), mesh span restoration, redial, etc. Benefits of adding p-cycles to a set of these methods? Benefits of planning network capacity jointly for these methods? New joint planning model

3. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 3 Capacity redundancy vs. Restoration time Restoration time Capacity redundancy APS 1+1 p-Cycles Shared Backup Path Protection True Mesh Path Restoration Mesh Span Restoration

4. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 4 Fixed CoP selection (without p-cycles) Service model Other possible CoPs, e.g. Unprotected and Redial, not included in analysis. Class of Protection (CoP) APS 1+160 ms Restoration time p-Cycles80 ms SBPP200 ms Network services Restoration time requirement 15% Demand mix (example case) 30% 55% Applications ≤ 60 ms ≤ 80 ms ≤ 200 ms

5. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 5 Fixed CoP selection (with p-cycles) Service model Other possible CoPs, e.g. Unprotected and Redial, not included in analysis. Class of Protection (CoP) APS 1+160 ms Restoration time p-Cycles80 ms SBPP200 ms Network services Restoration time requirement 15% Demand mix (example case) 30% 55% Applications ≤ 60 ms ≤ 80 ms ≤ 200 ms

6. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 6 Automatic CoP selection with upgrades Service model Other possible CoPs, e.g. Unprotected and Redial, not included in analysis. Class of Protection (CoP) APS 1+160 ms Restoration time p-Cycles80 ms SBPP200 ms Network services Restoration time requirement 15% Demand mix (example case) 30% 55% Applications ≤ 60 ms ≤ 80 ms ≤ 200 ms

7. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 7 Planning models Integer Linear Programming general model (AMPL, CPLEX) Minimal capacitydistance for full restorability under single failures Selection of fastest CoPs Separate optimization (fixed CoP selection) Joint optimization (automatic CoP selection) With p-Cycles Without p-Cycles (benchmark) or Min Upgrade to faster CoP whenever economical 1 2 3 With p-Cycles

8. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 8 Two network models U.S. Europe Average nodal degree = 4.73 Average nodal degree = 3.26

9. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 9 Results – U.S. network Benchmark -3.4% -8.7% CoP upgraded demands: 32% 123

10. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 10 Results – Europe network -11.6% -14% Benchmark CoP upgraded demands: 24% 123

11. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 11 Class of Protection upgrade examples Upgrade from p-cycle to APS 1+1 Upgrade from SBPP to p-cycle working p-cycle A C B D E

12. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 12 Class of Protection upgrade examples Upgrade from p-cycle to APS 1+1 Upgrade from SBPP to p-cycle working p-cycle cap = 10 A C B D E APS “spare” w1 cap = 10 w2 = 10 A C B D E w3 = 20

13. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 13 Conclusions p-Cycles could replace APS 1+1 for some traffic demands – where slight restoration time penalty is acceptable

14. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 14 Conclusions p-Cycles could replace APS 1+1 for some traffic demands – where slight restoration time penalty is acceptable New capacity planning model allowing automatic selection of protection & restoration method – Upgrade demand to faster CoP whenever economical

15. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 15 Conclusions p-Cycles could replace APS 1+1 for some traffic demands – where slight restoration time penalty is acceptable New capacity planning model allowing automatic selection of protection & restoration method – Upgrade demand to faster CoP whenever economical Mixed protection & restoration: – Adding p-cycles: 1% - 19% capacity savings – Jointly plan all CoPs: 4% - 22% capacity savings – Upgrades to faster CoP: 0 - 45% Provide better service for some traffic without adding capacity

16. Benefits of p-Cycles in a Mixed Protection and Restoration Approach DRCN 2003 16 Thank you