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IP Restoration on WDM Optical Networks. Hwajung Lee*, Hongsik Choi, Hyeong-Ah Choi The George Washington University Department of Computer Science. Contents. Terminology Problem Formulation Main Results Lemma 1 Lemma 2 Theorem Conclusion Further Work. IP WDM. Terminology.

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Ip restoration on wdm optical networks

IP Restoration on WDM Optical Networks

Hwajung Lee*, Hongsik Choi, Hyeong-Ah Choi

The George Washington University

Department of Computer Science


Contents
Contents

  • Terminology

  • Problem Formulation

  • Main Results

    • Lemma 1

    • Lemma 2

    • Theorem

  • Conclusion

  • Further Work


Terminology

IP

WDM

Terminology

  • WDM : Wavelength Division Multiplexing

  • IP over WDM Optical Network

    : Network structure with IP protocol as an upper

    layer and WDM Optical Network as a lower layer.

  • Lightpath : Transfer Path from Source to Sink in Optical Networks


Problem formulation
Problem Formulation

  • Given: IP Topology G, and WDM Topology G0

  • Objective: To find mappings f and h, where f maps each vertex of V(G) into a vertex in G0 and h maps each link of E(G) into a lightpath in G0, which that, for any source-sink pair s and t, if G has two link-disjoint paths from s to t, there exist two sequences of link-disjoint paths from s to t in G0.

    For any nodes u, vV(G),f(u)f(v) in any mapping f.


Example of the problem

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Example of the Problem

  • Fault Propagation on IP over WDM

IP Layer

WDM Layer


Example of a solution

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Example of a Solution

IP Layer

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WDM Layer

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Overview of main results
Overview of Main Results

  • Lemma 1: Any vertex mappings are acceptable in case of 3-edge-connected.

  • Lemma 2: Given G is 2-edge-connected, G is tolerant to single link faults of G0 iff edge cuts of size two of G are mapped with a vertex mapping f and an edge-to-path mapping h, under the condition of Lemma 2.

  • Theorem: Given G is 2-edge-connected and G0 is a ring, G is tolerant to single link faults of G0.


Lemma 1
Lemma 1

  • If G is 3-edge-connected, for any vertex mapping f:V(G)  V(G0), an edge-to-path mapping h: E(G)  P(G0) ensuring that G is tolerant to single link faults of G0.

     a mapping h of

    MaxeE(G0){# of wavelengths on an edge}  2

    There must be at least one live path in the case of single link faults causing at most 2 edge disable.


Proof of lemma 1
Proof of Lemma 1

IP Layer

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Mw=2

Mw=3

WDM Layer

Mw=Maxe E(G0){# of wavelengths on an edge}



Lemma 2
Lemma 2

  • Suppose G is 2-edge-connected.

    Let f: V(G)  V(G0), and h: E(G) P(G0) be mappings such that G is tolerant to single link faults, iff, for any edge cuts of size two

    {ei=(a, b), ej=(c,d)} in G if there exists any, ordering of vertices in G0 is not f(a)-f(c)-f(b)-f(d) in the clockwise or counterclockwise direction.


Example of lemma 2

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Example of Lemma 2

IP Layer

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WDM Layer

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Theorem
Theorem

  • Given G is 2-edge-connected and G0 is a ring,G is tolerant to single link faults of G0.

     It is obtained based on the Lemma 1

    and Lemma 2.


Mapping example

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Mapping Example

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Conclusion
Conclusion

  • Lemma 1: Any vertex mappings are acceptable in case of 3-edge-connected.

  • Lemma 2: Given G is 2-edge-connected, G is tolerant to single link faults of G0 iff edge cuts of size two of G are mapped with a vertex mapping f and an edge-to-path mapping h, under the condition of Lemma 2.

  • Theorem: Given G is 2-edge-connected and G0 is a ring, G is tolerant to single link faults of G0.


Further work
Further Work

  • Consider a mesh Topology as the underlying WDM structures.

  • Consider Load Balancing issues

    • Minimize

      Maxe E(G0){the number of wavelengths on an edge}.

  • Set up Lightpath based on # of available wavelengths

    & Integrate it into MPLamdaS.



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