1. Page 1 NEPTUNE Alternate System Design Peter Phibbs 7-8 January 2003

2. Page 2 Outline What is the Alternate System Design? Communications System Power System Reliability Implications Commercial Implications Current Status Next Steps Conclusions

3. Page 3 What is the Alternate System Design? Backbone Built to Commercial Submarine Telecommunications Standards –Leverages Industry Experience –Consists of Cable, Optically Amplified Repeaters, and Branching Units –Delivers Extremely High Reliability Science Nodes Built to Meet NEPTUNE Project Needs –Include Power Converters, Gigabit Ethernet Transponders, and Ethernet Switches –Use of Terrestrial Grade Equipment Trades-off Reliability for Function A Philosophy of Minimizing and Simplifying Underwater Equipment

4. Page 4 Alternate System Design North Shore Terminal South Shore Terminal Comms Link (Internet) Node Branching Unit Repeater

5. Page 5 Alternate System Design Features Topology Driven by Power, Not Comms Cable Run is Linear from Station to Station; No Branching Each Node Communicates with Both Cable Stations for Diversity Each Node Uses a Unique Wavelength on a Fiber Pair Data Does Not Pass Through Other Nodes on Way to Shore Station

6. Page 6 ASD Communications Node Configuration Ethernet Switch GigE Transponder Optical Filter Optical Couplers Optical Filter 10/100 Base-T To Instruments Node Branching Unit Node

7. Page 7 ASD Communications Node Configuration Ethernet Switch GigE Transponder Optical Filters Select Desired Wavelength Optical Coupler Drops All Waves from North Terminal and Adds Wave to South Terminal 10/100 Base-T To Instruments Node Branching Unit Node To/From North Shore Station To/From South Shore Station Optical Coupler Drops All Waves from South Terminal and Adds Wave to North Terminal Comms to/from Other Nodes Pass Through Branching Unit

8. Page 8 ASD Power

9. Page 9 Reliability Implications Nodes Do Not Rely on Other Nodes Node Failures Are Extremely Unlikely to Affect Other Nodes –Only exception are certain laser faults which cause interactions on the optical line Baseline Design Relies on Mesh to Route Around Failed Nodes –This is Effective for Certain Combinations of Failures The Alternate Design Relies on Multiple Rings –In General, Rings are a Less Effective Topology Than a Mesh –Because Each Node Uses a Unique Wavelength, Each Node is an Independent Ring –Multiple, Overlaid Rings Enhance Reliability Preliminary Reliability Calculations Indicate Alternate Design Compares Favorably to Baseline Alternate Design Copes With Unpredictable Failures –Cable Break + Node Failure –Catastrophic Node Failure

10. Page 10 Baseline Design

11. Page 11 Baseline Design

12. Page 12 Baseline Design

13. Page 13 Shore Station Shore Station Baseline Design

14. Page 14 Alternate System Design

15. Page 15 Commercial Implications Backbone Provided Under Supply Contract Supplier Assumes Performance Risk Service and Support for Minimum of 15 Years Costs Still to Be Assessed; Both Baseline and Alternate are Moving Targets

16. Page 16 Status of Alternate System Design Alternate System Design Preliminary Study Released November 2002 Alcatel Testing Indicates Optical Design is Feasible Support from Alcatel Has Been Adequate, But Alcatel Need to Generate Business/Revenues to Continue Study from Power Group Anticipated Shortly Interim Report Released in February

17. Page 17 Next Steps Digest Implications of Power System Design Update Further Demonstration of Gigabit Ethernet Transponder Optical Line Design –Repeater Spacing –Spur Cable Length –Number of Nodes Supported Network Management Design Analysis: –Is Network Management System Required to Ensure Reliability? Timing Distribution Detailed Cost Estimate Complete Reliability Analysis Interim Report Anticipated in February

18. Page 18 Summary Key Feature of Alternate Design is High Reliability Backbone Alternate System Design Is Worthy of Consideration Alternate Comms and Alternate Power Are Synergistic Reliability and Commercial Implications Differentiate Alternate Design Technical Challenges Remain Study and Evaluation of Alternate Design Is Ongoing