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BroadNets 2004, October 25-29, San Jose
Survivable Mapping Algorithm by Ring Trimming (SMART) for large IP-over-WDM networks Maciej Kurant, Patrick Thiran Swiss Federal Institute of Technology - Lausanne (EPFL), Switzerland
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We use only the IP restoration approach:
Survivability Link-survivable mapping Physical topology Mapping Logical topology Connected GL How to deal with failures? There are several methods Protection vs restoration WDM layer vs IP layer M GΦ We assume unlimited capacities of physical links. We use only the IP restoration approach: (The failures are detected at the IP layer, and a new route is found dynamically.)
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The problem is not new… … [Crochat97]
J. Armitage, O. Crochat and J. Y. Le Boudec, “Design of a Survivable WDM Photonic Network,” Proceedings of IEEE INFOCOM 97, April 1997. [Sasaki00] G. H. Sasaki and C.-F. Su and D. Blight, “Simple layout algorithms to maintain network connectivity under faults,” Proceedings of the 2000 Annual Allerton Conference. [Modiano02] E. Modiano and A. Narula-Tam, “Survivable lightpath routing: a new approach to the design of WDM-based networks,” IEEE Journal on Selected Areas in Communications, vol. 20, no. 4, 2002 [Giroire03] F. Giroire, A. Nucci, T. Taft, and C. Diot, “Increasing the Robustness of IP Backbones in the Absence of Optical Level Protection,” Proc. of IEEE INFOCOM 2003. [Modiano03] L-W. Chen and E. Modiano, “Efficient Routing and Wavelength Assignment for Recongurable WDM Networks with Wavelength Converters,” Proc. of IEEE INFOCOM 2003. …
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SMART - Survivable Mapping Algorithm by Ring Trimming
Our solution SMART - Survivable Mapping Algorithm by Ring Trimming or “by Cycle Contraction”
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The SMART algorithm (link-survivability example)
Contracted topology GC GC GC a b c e f g h e f g h e d d d A single node! Physical topology Mapping Logical topology GL GL GL a b c d f g h e a b c d f g h e a b c d f g h e GΦ GΦ GΦ Iteration 1 Iteration 2 Iteration 3
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Large scale example
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Large scale example
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Large scale example
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Large scale example
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Large scale example
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Large scale example
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Large scale example
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Large scale example
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Large scale example
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SMART vs. Tabu Search (1) Random (2‑node‑connected) Tabu Search is widely used to solve the problem of survivability Our Tabu Search implementation followed the one in [Crochat97] Logical topology: random graphs of average degree 4 f-lattice (2‑node‑connected) Physical topology: f-lattice, f = 0…0.35
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SMART vs. Tabu Search (2) SMART finds a link-survivable mapping 10-30% more often than Tabu97 does.
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SMART vs. Tabu Search (3)
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SMART vs. Simple Layout Algorithm (1)
Random (2‑node‑connected) Simple Layout Algorithm [Sasaki00], similarly to SMART, breaks down the survivable mapping problem into a set of small and easy to solve subproblems – should be fast! f-lattice (2‑node‑connected) Logical topology: random graphs of average degree 4 Physical topology: f-lattice, f = 0…0.35
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SMART vs. Simple Layout Algorithm (2)
Simple Layout Algorithm is about 3 times faster than SMART.
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SMART vs. Simple Layout Algorithm (3)
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Applications of SMART 1) Single-link failures 2) Span failures 3) Node failures 4) Double-link failures
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Double-link failures (1)
Idea: Take 3-edge connected structures instead of cycles.
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Conclusions SMART is 2-3 orders of magnitude faster than other heristics, and more scalable SMART works well with many types of failures (single link, span, node and double link) Future work: Formal analysis of SMART Introduction of limited capacities of physical links
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Thank you!
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Double-link failures (any two links may fail)
Application 4 Double-link failures (any two links may fail)
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Double-link failures (2)
Random graph (3-edge-connected) 1 2 4 7 8 3 6 5 9 11 10 14 13 12 Logical topology: 1 2 4 7 8 3 6 5 9 11 10 14 13 12 NSFNET Physical topology: NSFNET3EC
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Double-link failures (3)
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