Network Design Issues for a Terabit optical Internet

1. Network Design Issues for a Terabit optical Internet 元智大學 資訊工程學系 王志誠

2. Outline • 3Tnet • Design and planning methods • Dimension and Routing • Topology design • Conclusion and further works

3. 3Tnet : 863 • Next Generation high performance optical Internet • Define, demonstrate, and determine how best to achieve pure IP tech serving. • Transparent, reconfigurable, scalable, long distance(>500km) Tb line sys. • High-throughput, low-latency transport of IP packets

4. Design and planning methods • Connect China’s east 4 major City and a metropolitan intelligent optical network. • Require efficient planning methods

5. Design and planning methods • Planning methods: 3 parts • Dimensioning : the choice and placement of optical switch devices • Routing : satisfy the diversity location restrictions. • Wavelength assignment : not used more than available at the link. • Dimensioning is disregarded.

6. Design and planning methods • The design of optical network arch : 2 aspect • Physical topology :statically designed and planned at the beginning. • Logical topology :more difficult, more issues. 2-class problem • Optimisation of traffic matrix(load balance, non-blocking) • Linear Programming problem under various constraints

7. Design and planning methods • Switching node arch : careful design • Physical : • Cross talk, amplifier gain, output power,power equalisation. • Non-Physical : • protection/restoration type, access service type, stability, scalability, resilience.

8. Design and planning methods • Monitoring and Management • Optical Spectrum Analyzer (OSA, embedded) • freq, power, signal to noise ratio (OSNR) • Bit Error Rate (BER) • Digital Wrapper (DW) tech • Forward Error Correction (FEC)

9. Design and planning methods • Published growth rate data :host, modem usage, population, employee • China's national backbone network is planned to be 12 Tb/s by the end of 2005. • 77% compound annual growth rate percentage

10. Dimension and Routing • Gulou in Nanjing • Yushan in Changshu • Beicai in Shanghai • Dianxin building in Hangzhou • Focus on Shanghai

11. Dimension and Routing

12. Dimension and Routing

13. Topology design • Lightpaths : established as logical connections between pairs of routers • Intelligent Optical Switch (IOS) : containing the splitting and switching functions.

14. Topology design • 2 interconnected optical sub networks connecting 6 Shanghai commercial districts • the Beicai working as a traffic aggregated and grooming point of the 3Tnet

15. Topology design

16. Topology design • 2 challenge • lightpaths routing strategies • lightpath length limitations due to physical restrictions. • IP router demands are determined in terms of optical channels (lightpaths)

17. Topology design

18. Topology design • lightpaths protection and restoration • protection/restoration protocols such as IP router topology reconfiguration. • 2 main approaches are protection and restoration.

19. Topology design • Protection • a preassigned capacity between nodes is used to replace the failed entities • Restoration • Rerouting algorithms computing new paths whenever failures occur.

20. Topology design • Higher complexity of the restoration process generates a longer network reconfiguration time compared to automatic protection mechanisms. • More complex algorithms aiming at a better sharing of resource could be more time consuming.

21. Topology design

22. Topology design

23. Conclusion and further works • Efficient planning and design of 3Tnet networks is an important issue for the success of the project. • The network planning for optical Internet is very complicated by introducing various constraints that cause tradeoffs for certain desired factors