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| 2. |
- Fouquet, Y., et al.
(författare)
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Elastic Rerouting - models and resolution methods
- 2014
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Ingår i: [Host publication title missing]. - 9781479970391 ; , s. 47-53
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Konferensbidrag (refereegranskat)abstract
- This study is concerned with an original traffic restoration strategy for wide-area communication networks called Elastic Rerouting (ER). ER aims at alleviating the tradeoff between the network cost and traffic restoration complexity observed in existing solutions. We present the strategy, provide a mathematical formulation for the ER related optimization problem, and discuss an approach to its resolution.We also report results of a numerical illustrating effectiveness of ER in terms of the link capacity cost
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| 3. |
- Fouquet, Y., et al.
(författare)
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Elastic routing: A distributed variant, implementation issues and numerical results
- 2013
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Ingår i: [Host publication title missing]. ; , s. 98-104
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Konferensbidrag (refereegranskat)abstract
- This study is concerned with a specific rerouting strategy in telecommunication networks named Elastic Robust Rerouting (ERR), introduced first in [8]. We recall main points on this strategy, provide mathematical formulation and discuss in details a solution method. The second question studied in this paper is concerned with its distributed version and some related implementation issues. We report a numerical study on effectiveness of both versions in terms of dimensioning cost, restoration time and management effort.
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| 4. |
- Fouquet, Y., et al.
(författare)
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Flow Adjustment - a Flexible Routing Strategy for Demand Protection Against Multiple Partial Link Failures
- 2014
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Konferensbidrag (refereegranskat)abstract
- In this paper, we study a flexible routing strategy for demand protection and a corresponding optimization problem for networks that permanently experience fluctuations of the capacity available on their links. This is an important and novel topic as limited link availability is a fundamental feature of wireless networks; yet majority of work in survivable network design is restricted to total failures of single links. Hence, protection against partial failures of multiple links is considered as congestion avoidance. We assume a given finite set of network states. Each state is characterized by a vector of link availability coefficients specifying, for each link, the fraction of its nominal (maximum) capacity available in this state, and by a traffic coefficients vector specifying, for each demand, the proportion of its nominal traffic to be realized in the considered state. Our routing strategy allows for adjustment (thinning or thickening) of the reference path-flows. For a given nominal value x of a path-flow, its thickening is limited to Tx where T is a given constant greater than or equal to 1. Thus, in each state, the value of every path-flow can range from 0 to T times its reference value. It turns out that the corresponding link cost minimization problem (where link capacities and state-dependant path-flows are decision variables) is NP-hard. We present a non-compact linear programming formulation of the problem together with a solution algorithm based on path generation. We illustrate the effectiveness of the introduced routing strategy by presenting numerical results for a set of representative network examples.
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| 5. |
- Fouquet, Y., et al.
(författare)
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Flow adjustment methods for survivable networks
- 2014
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Ingår i: [Host publication title missing].
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Konferensbidrag (refereegranskat)abstract
- The presented study deals with a specific rerouting strategy for protecting traffic flows in communication networks called Flow Adjustment Routing. The strategy is designed to handle partial link failures. We present two variants of the strategy and analyze their pros and cons. We show that the initial strategy is not directly implementable to cope with severe link failures such as total link failures. Therefore, we propose a restricted flow adjustment version as well as its distributed variant that can be used for the total link failures case. Numerical experiments for different settings and test networks illustrate the findings.
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| 7. |
- Pioro, Michal, et al.
(författare)
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An optimization model for communication networks with partial multiple failures
- 2013
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Ingår i: [Host publication title missing]. - 2157-0221. ; , s. 171-178
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Konferensbidrag (refereegranskat)abstract
- This paper studies optimization issues related to a proposed traffic protection strategy referred to as flow-thinning strategy (FTS). FTS is an extension of the well known protection concept, called path diversity, to the case of partial multiple link failures. Path diversity assumes that when a certain subset of links fail, then their capacity is entirely lost and the nominal path-flows that are not affected by the failure are sufficient to realize the required demand. FTS, in turn, is designed to work also when link failures are partial, that is, the failing links in general lose only a fraction of capacity. We consider a link dimensioning problem for FTS, called flow-thinning optimization problem (FTOP), and discuss its properties. It turns out that FTOP, in its general setting, is NP-hard so that its linear programming formulations are unavoidably non-compact and require path generation. As in the general case path generation is also difficult, we propose an integer programming formulation of the pricing problem for the general case of failure scenarios. We also exhibit two special cases when the pricing problem can be solved in polynomial time. Finally, we present a numerical study illustrating cost effectiveness of FTS. The considered partial multi-link failure scenarios are relevant for wireless networks and for the upper layers of fixed communication networks, as for example the MPLS layer with greedy elastic traffic demands.
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