32 documents found, page 1 of 4
A New Linear Path Pair Availability Constraint for Network Design
Martins, Lúcia; Santos, Dorabella; Girão-Silva, Rita; Gomes, TeresaIt is essential for network operators to guarantee required levels of availability in the network without incurring in excessive costs. We address the optimization problem of upgrading links at a given cost, to achieve end-to-end availability guarantees in the network, via pairs of working and backup paths. These guarantees are expressed as nonlinear path pair availability constraints which cannot be readily li...
Near Optimal Network Design for Path Pair Availability Guarantees
Santos, Dorabella; Martins, Lúcia; Gomes, Teresa Martinez dos Santos; Silva, Rita Cristina Girão Coelho daGuaranteeing high levels of availability in the network in a cost effective manner is of primary importance to network operators and managers. We address the network design problem for path pair availability guarantees, assuming links can be upgraded to have an increased availability. Since the path pair availability constraints are non-linear and not linearizable in an exact manner, this mathematical problem h...
Determining the Minimum Cost Steiner Tree for Delay Constrained Problems
Martins, Lúcia; Santos, Dorabella; Gomes, Teresa; Girão-Silva, RitaWe address a variant of the Steiner tree problem for delay constrained problems. The addressed problem consists in determining the minimum cost Steiner tree, while guaranteeing that the delay between any two terminal nodes does not exceed a given maximum value. This problem is known as the bounded diameter Steiner minimum tree problem. We propose a compact formulation based on integer linear programming (ILP) t...
A centrality-based heuristic for network design to support availability differe...
Girão-Silva, Rita; Gomes, Teresa; Martins, Lúcia; Tipper, David; Alashaikh, AbdulazizIn today's society, communication networks are of paramount importance, and providing adequate levels of availability of the resources in a cost effective way is crucial for network managers. We consider the design of a high availability structure (a spine) in the network, so that a desired availability for the network flows may be achieved. The tackled problem involves the selection of the edges forming the sp...
Disaster-Resilient Routing Schemes for Regional Failures
Gomes, Teresa; Santos, Dorabella; Girão-Silva, Rita; Martins, Lúcia; Nedic, Boro; Gunkel, Matthias; Vass, Balázs; Tapolcai, János; Rak, JacekLarge scale natural disasters can have a profound effect on the telecommunication services in the affected geographical area. Hence, it is important to develop routing approaches that may help in circumventing damaged regional areas of a network. This prompted the development of geographically diverse routing schemes and also of disaster-risk aware routing schemes. A minimum-cost geodiverse routing, where a min...
Enhancing Availability for Critical Services
Gomes, Teresa; Martins, Lúcia; Girão-Silva, Rita; Tipper, David; Pasic, Alija; Vass, Balázs; Garrote, Luís; Nunes, Urbano; Zachariasen, MartinTraditional approaches to provide classes of resilient service take the physical network availability as an input and then deploy redundancy and restoration techniques at various layers, often without full knowledge of mappings between layers. This makes it hard (and often inefficient ) to ensure the high availability required by critical services which are typically a small fraction of the total tra c. Here, t...
Minimization of the network availability upgrade cost with geodiverse routing f...
Sousa, Amaro de; Gomes, Teresa; Girão-Silva, Rita; Martins, LúciaTelecommunication networks are a critical infrastructure of our society. Wide area backbone communication networks are based on optical networks, where each fiber has a very large capacity. These networks must offer high end-to-end availability and a high resilience to large-scale disasters. Routing with geodiversity can mitigate the impact of disasters but will result in longer paths, making it difficult to ac...
Heuristic Approach for the Design of a High Availability Structure
Girão-Silva, Rita; Martins, Lúcia; Gomes, Teresa; Tipper, David; Alashaikh, AbdulazizCommunication networks are critical in today's society and the availability of resources is a major concern for network managers. Adequate levels of availability for every demand must be provided in a network, to assure an adequate grade of service to the users. In this work, a set of edges is selected to provide a high availability path (the working path) and/or a high availability path pair (working path plus...
Improving Network Availability—A Design Perspective
Girão-Silva, Rita; Martins, Lúcia; Gomes, Teresa; Alashaikh, Abdulaziz; Tipper, DavidThe availability of the resources in communication networks is critical, due to the impact that possible disruptions of communication services may have in the society. Therefore, providing adequate levels of availability for every demand in a network is of paramount importance. In this work, we focus on the topological structure of a network to select a set of links that provide a high availability path to be u...
Weighted Euclidean Steiner Trees for Disaster-Aware Network Design
Garrote, Luís; Martins, Lúcia; Nunes, Urbano J.; Zachariasen, MartinWe consider the problem of constructing a Euclidean Steiner tree in a setting where the plane has been divided into polygonal regions, each with an associated weight. Given a set of points (terminals), the task is to construct a shortest interconnection of the points, where the cost of a line segment in a region is the Euclidean distance multiplied by the weight of the region. The problem is a natural generaliz...