Public defence of Ph.D. thesis Network Layer Studies of the Hybrid Optical Migration Capable

1. Public defence of Ph.D. thesis Network Layer Studies of the Hybrid Optical Migration Capable Network with Service Guarantees Presented on the 6th of May 2011 Andreas Kimsås Name, title of the presentation

2. Agenda • Optical Internet backbone networks • OpMiGua Concept • Hybrid networks • Research papers • Physical layer aspects & switch design • Performance evaluation of original concept • Reliability aspects • Extensions to orignal concept • Conclusions

3. Basic concepts & future needs optical networks

4. Network overview Divided into capacity and extent; access, metro & core Data, control & management planes Distributed control and management. Several protocols and management strategies in use. Diverse physical and logical topologies Diversity in equipment at physical and medium access level A wide range of services to be supported A non-homogeneous mix

5. Service requirements Bandwidth, Reliability & Performance The OpMiGua network should accomodate high bandwidth as well as differentiated QoS and QoR.

6. Technical concept & project organization The opmigua project

7. The OpMiGua node Guaranteed Service Type (GST) traffic is wavelenght routed Statistically multiplexed (SM) traffic is packet switched onto the GST circuits. Absolute priority to GST traffic. Requires dectection of traffic class (e.g. polarization), and logic for inserting SM packets. Simplified operation Combining circuit & packet switching

8. The OpMiGua network SM layer: logical = physical topology. SM traffic is routed hop by hop, but may use a GST connection that terminates in a different place. GST layer: logical != physical topology. No processing required in core nodes. GST traffic is unaffected by SM packets Physical layer: GST and SM packets share the same wavelength, but are not superimposed in time. Simplified operation Physical and logical dataplanes

9. OpMiGua project Partners: NTNU, Telenor & Network Electronics OpMigua concept presented in 2003 by S. Bjørnstad, the 3 year joint project stared in 2004. 30 conference & journal papers, 7 master thesis and 2 Ph.D thesis Physical layer (Tuft), Network layer (Kimsås) - a joint industry/university project Home page: www.opmigua.com

10. Classification of Hybrid networks

11. Hybrid network classification • G-MPLS • PATON • Light-Frame • HOS • SLIP-IN • HOTNET • OBTN • OpMiGua • ORION • Hy-Labs «An optical network architecture is called hybrid if it combines two or more basic network technologies at the same time», Gauger & Breusegem

12. A short overview of the Research papers

13. Publications Nine included papers (P1-P9).N6 is not included in the thesis. 5 reasearch areas combining simulation, experiment & analysis. I am the first author in 5 papers. P4 is the result of COST-291 collaboration with IKR, Stuttgart a quick overview Home page: www.opmigua.com

14. P1: Bit errors & packet loss a cross-layer study • Goal: to show the relation between BER and PLR • Method: i.i.d. and constant BER at each hop. • Result: If the network already has moderate PLR the system can use higher than «usual» BER, without affecting the performance. • Also, FEC is much more important in OBS networks than for the OpMiGua network. Ref: A. Kimsås, H. Øverby, S. Bjørnstad, V. L. Tuft: “A Cross Layer Study of Packet Loss in All-Optical Networks”, AICT, 2006

15. P2: AWGshare switch design Functionally equivalent to 3-stage Clos • Very low PLR from: • SNB property • Statistical multiplexing gain • buffering • Scalability demands: • Fully shared buffers • Realistic cascadability • Moderate coupling loss • Limited tuning range • Realistic AWG size Ref: A. Kimsås, S. Bjørnstad, N. Stol, D.R. Hjelme: “AWGshare - a Highly Scalable Optical Node Design with Fully Shared Buffers”, Optical Network Design and Modelling, 2011

16. P2: Switch design - Comparison with known designs • Number of AWG routers is function of F, not W • Tuning range is function of W, not FW • W buffer interfaces are saved compared to Clos & Ngo Ref: A. Kimsås, S. Bjørnstad, N. Stol, D.R. Hjelme: “AWGshare - a Highly Scalable Optical Node Design with Fully Shared Buffers”, Optical Network Design and Modelling, 2011

17. P3: Packet loss in anOpMigua node It is crucial to account for reservation induced blocking (RIB). Closed form expression was found, acting as a lower bound to packet loss. Approximation proved to give good agreement with simulations. GST load is increased as function of FDL delay D. Markov model (Engseth) A. Kimsås, H. Øverby and N. Stol: “Analysis of a BufferlessOpMiGua Node”, in AICT, 2009

18. P3: Analysis of an OpMigua node The PLR decreases as function of GST aggregation at ingress. A closed form expression was developed, excellent results for B > 100. Results A. Kimsås, H. Øverby and N. Stol: “Analysis of a BufferlessOpMiGua Node”, in AICT, 2009 When increasing the share of GST traffic RIB causes an inital rise in PLR. It is followed by a sharp drop. Approximation gives significant error when S > 0.8, but confirms trend.

19. P4:OBS vs. OpMiGua - Node comparison of burst/packet loss • Ingress GST packetsare aggregated into bursts, the aggregation process was simulated • OBS JET provides a fair comparison. Varied load, low/high priority share and switch size • OpMiGua outperforms OBS. In all the simulation cases. • Burst segmentation should reduce the difference. J. Scharf, A. Kimsås, M. Kohn and G. Hu, “OBS vs. OpMiGua - A Comparative Performance Evaluation”. ICTON, 2007

20. P5: Sheduling SM packets - 4 alternatives A. Kimsås, S. Bjørnstad, H. Øverby and N. Stol: ”Reservation Techniques in an OpMiGua Node”, ONDM, 2007

21. P6: Differentiated survivability - Three pragmatic alternatives N. Stol, H. Øverby, S. Bjørnstad, A. Kimsås and A. Mykkeltveit: “Differentiated survivability in the OpMiGua Hybrid Optical network”, in ONDM, May 2006

22. P7: Trafficability during failure Routing all traffic via the packet switch • Contention resolution through preemption in a rearrangable non-blocking OPS • Compared to AWGshare the tuning range is reduced with 50% and a third switching stage is not needed. • Simulation results show that output contention dominates over internal contention. A. Kimsås, H. Øverby, S. Bjørnstad and N. Stol: "Performance in a Failure Situation of an OpMiGua Packet Switch with Internal Blocking". ICTON, 2006.

23. P8: Network study A bufferless scheme using erasure codes A. Kimsås, S. Bjørnstad, H. Øverby and N. Stol: "Improving performance in the OpMiGua hybrid network employing the network layer packet redundancy scheme". Communications, IET, 2010.

24. P8: Network study Comparing RedGST and RedSM Spikes in PLR are caused by overloaded GST circuits. The redundancy packets newer gets transmitted from the ingress queue. In presence of non-uniform traffic, the flexibility of packet switched RedSM traffic gives a smooth and predictable variation in PLR. A. Kimsås, S. Bjørnstad, H. Øverby and N. Stol: "Improving performance in the OpMiGua hybrid network employing the network layer packet redundancy scheme". Communications, IET, 2010.

25. Extensions Ideas for further studies S. Bjørnstad and A. Kimsås: "Hybrid packet/time slotted circuit switched scheme (HPTS)", ICTON, 2008.

26. Key findings

27. N6: Lab implementation using all-optical polarization labels • GST loss could in principle occur if the SOP is poorly aligned, or due to issues in insertion logic. SM experiences contention. Ref: S. Bjørnstad, et al.: “Demonstration and analysis of TV and data transport in the OpMiGua hybrid circuit/packet switched network testbed”, ECOC, 2007.

28. N6: Physical demonstration with all optical polarization labels GST data is error free. No artifacts in video experiment. Ref: S. Bjørnstad, et al.: “Demonstration and analysis of TV and data transport in the OpMiGua hybrid circuit/packet switched network testbed”, ECOC, 2007.

29. G-MPLS extentions S. Bjørnstad and A. Kimsås: "Hybrid packet/time slotted circuit switched scheme (HPTS)", ICTON, 2008.