1 Sep. 2009

© Rui Wang

Cycle-Oriented Distributed Preconfiguration

Ring-like Speed with Mesh-like Capacity for Self-planning Network Restoration

1 Sep. 2009

Rui Wang

Department of Electrical Engineering & Computer Science

Information Technology & Telecommunications Research Center

ResiliNets Research Group

The University of Kansas

[email protected]

© Rui Wang

1 Sep. 2009 Cycle-oriented distributed preconfiguration 2


AbstractCycle-oriented preconfiguration of spare capacity is a new idea for designing and operating mesh-restorable networks. It aims to attain the capacity-efficiency of a mesh-restorable network, while approaching the speed of self-healing rings. Compare with self-healing rings, the method contributes more failure schemes to the restoration .

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Outline• The concept of Cycle Preconfiguration • Optimal Design of p-cycle Restorable Networks• Self-organization of the p-cycle state• Conclusion

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The concept of Cycle Preconfiguration • The concept of Cycle Preconfiguration • Optimal Design of p-cycle Restorable Networks• Self-organization of the p-cycle state• Conclusion

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The concept of Cycle Preconfiguration • Background- mesh-restorable network- self-healing rings network

• Motivation- real-time restoration of mesh networks- increase the speed of mesh-based restoration schemes

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The concept of Cycle Preconfiguration • P-cycles: base on the formation of pre-

configured cycles- more widely protect the network as a whole- two nodes have real-time cross-connection workload for

any failure

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The concept of Cycle Preconfiguration • Fig. a- an example of p-cycle

• Fig. b- a span on the cycle

breaks and the remaining arc restore

• Fig. c and d- p-cycle can be accessed

for restoration of working paths that are not on the cycle

[Credit: Grover-Stamatelakis-1998]

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The concept of Cycle Preconfiguration Comparison of the p-

cycle and ring technologies

- the speed of rings, with the efficiency of mesh network


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Optimal Design of p-Cycle Restorable Networks

• The concept of Cycle Preconfiguration • Optimal Design of p-Cycle Restorable Networks• Self-organization of the p-cycle state• Conclusion

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• How p-cycle is generated- Linear integer program (IP) is formulated

- simple distinct cycles are generated from the network topology

- IP generate an optimal p-cycle plan

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• Two p-cycle variations are developed and tested

- a p-cycle plan within an existing mesh network spare capacity

- a fully restorable plan minimizing spare capacity

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• Excess Sparing- percentage of spare capacity p-cycle design required above

the mesh spare capacity design




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Self-organization of the p-cycle state• The concept of Cycle Preconfiguration • Optimal Design of p-Cycle Restorable Networks• Self-organization of the p-cycle state• Conclusion

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• DCPC (Distributed Cycle PreConfiguration)- an adaption of the statelet processing rules of SHN (Self

Healing Network) protocol- deployment and adaptation of the network cycle

preconfiguration state

• Statelet - embedded on each spare link and contains state fields- incoming statelet- outgoing statelet- broadcast through a network- statelet format: index, hopcount, sendnode, numpaths,

route


Self-organization of the p-cycle state

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• The p-cycle process - each node explores the network for p-cycle candidates - hand off to the next node in order - all nodes show its best found cycle - the competition flood expands through the network - the globally best cycle candidate dominates everywhere - nodes on the p-cycle update pre-plans to exploit the

new one - repeat until a complete deployment of p-cycles is built

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• Two node roles in the DCPC- Cycler: in charge of the cycle-exploration process within

the network- Tandem node: mediate the statelet broadcast

competition



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• The Tandem Node - rules determine what p-cycle candidate the cycler node will discover - a new incoming statelet displace an outgoing statelet

- statelets forward to adjacent nodes- from a Cycle node to Cycle node- from a Tandem to Cycle node




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• Statelet’s score: s=(numpaths)/(hopcount)- numpaths: the number of useful paths- hopcount: the number of spans traverse in the statelet’s

route



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• The Cycler Node Role - the cycler places an outgoing statelet on one spare link - the cycler node invests a pre-determined time - the cycler maintains a record of received statelet with the best score - it grows in size as it improves its score




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• Six main regions appear in the plot• 10 individual cycler node exploration• In the last region no node finds any feasible p-cycle

candidates and the protocol terminates




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• DCPC protocol performance assessment• The p-cycle restorability levels achievement• Trigger a follow-up real-time restoration protocol




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Conclusion• The concept of Cycle Preconfiguration • Optimal Design of p-Cycle Restorable Networks• Self-organization of the p-cycle state• Conclusion

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Conclusion• Cycle-oriented preconfiguration of spare

capacity is a technological enabler for restoration with the speed of rings while retaining the capacity efficiency of a span restorable mesh network

- restoration is performed by simply breaking into these cycles and substituting traffic at failure time

- it remains a mesh restoration technology

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Reference

• [Credit: Grover-Stamatelakis-1998]• W.D. Grover and D. Stamatelakis,

"Cycle-oriented distributed pre-configuration: ring-like speed with mesh-like capacity for self-planning network restoration",in Proc. IEEE International Conf. Commun. (ICC '98), pp. 537-543, Atlanta, June 8-11, 1998

1 Sep. 2009

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