1. Cut Saturation for p-cycle Design Khalid Al-Snaie Electronics Dept., College of Technology Riyadh, Saudi Arabia Dale R. Thompson* Department of Computer Science & Computer Engineering (CSCE) University of Arkansas

2. Ring vs. Mesh

3. Two Enemies of Fiber

4. Four-fiber Bidirectional Line- Switched Ring (BLSR), no failure

5. Four-fiber BLSR, span switching

6. Four-fiber BLSR, ring switching

7. Wavelength-Division Multiplexing Red Green Blue

8. Wavelength Path #1 S1 S2 S3 D1 D3 D2 1 2 1

9. Wavelength Path #2 S1 S2 S3 D1 D3 D2 1 2 2

10. Virtual Wavelength Path (VWP) S1 S2 S3 D1 D3 D2 1 2 2

11. One preconfigured protection cycle (p-cycle), no failures

12. One p-cycle, on-cycle span failure

13. One p-cycle, straddling span failure

14. SCP vs JCP in p-cycles Spare capacity placement (SCP) –Route demand using shortest paths –Apply capacity algorithm to find set of p-cycles that minimize spare capacity cost Joint capacity placement (JCP) –Apply capacity algorithm to find working routes and set of p-cycles that minimize spare capacity cost.

15. Cut Saturation

16. p-cycle Cut Saturation (PCUT) Load topology and traffic demand. do { Route traffic with JCP or with shortest path algorithm if using SCP. Sort spans by load in descending order. Remove spans one at a time until the network separates into two disconnected components N1 and N2. Add a new span between one of the lowest degree nodes in N1 and one of the lowest degree nodes in N2. Replace deleted spans. Find p-cycles with SCP or JCP. Calculate spare-to-working capacity ratio. } while (spare-to-working capacity ratio is greater than a threshold)

17. NSF Network

18. Add span #1 (N0 to N9)

19. Add span #2 (N7 to N14)

20. Add span #3 (N15 to N24)

21. Add span #4 (N10 to N23)

22. Final Answer (N0 to N9, N7 to N14, N15 to N24, N10 to N23)

23. Spare-to-working capacity Location of new spans Avg Node Degree S/W SCP (%) S/W JCP (%) S/W Bound (%) Original network 3.21826045 N0 to N9 3.28765244 N0 to N9, N7 to N14 3.36725142 N0 to N9, N7 to N14, N15 to N24 3.43695041 N0 to N9, N7 to N14, N15 to N24, N10 to N23 3.50664840

24. Contact Information Dale R. Thompson, P.E., Ph.D. Department of Computer Science and Computer Engineering University of Arkansas 311 Engineering Hall Fayetteville, Arkansas 72701 Phone: +1 (479) 575-5090 FAX: +1 (479) 575-5339 E-mail: d.r.thompson@ieee.org WWW: http://csce.uark.edu/~drt/