Automatic map-based FTTx access network design

Several mature and standardized optical access network technologies are available for network operators providing broadband services, being now in deployment phase; therefore cost estimation, business analysis, efficient deployment strategies, network and topology design issues for FTTx access networks play an increasingly important role regarding profitability and market success. In a competitive environment, techno-economic evaluation supports the optimal choice among available technologies. Even the tradeoff between future proof technical superiority and short term investment minimization requires a farseeing decision. In our point of view, cost estimation and techno-economic evaluation is strongly related to strategic network design: among others the uneven population density, irregular street system or infrastructure have significant impact on the network topology, thus the deployment costs as well. In order to deal with these aspects, a high-level, strategic network design is necessary that adapts to geospatial characteristics of the services area, providing accurate and detailed network information for the techno-economic evaluation [1]. We have developed a topology designer methodology that supprts the above requirements, providing (near) optimal topology of the fully or partially optical access network, based on the geospatial information about the service area: digital maps, existing infrastructure and subscriber database. Automatic topology design for large-scale service areas, with 10.000s of subsribers is a highly complex mathematical problem. The tough algorithms for a near optimal, yet efficient solution. The developed algorithms were evaluated regarding their speed and accuracy. Based on topology design results, a detailed and flexible techno-economic comparison is carried out, since the framework handles various broadband access network technologies, as presented in a case study. --Topology design,Strategic Design,Network planning,GIS,Map,Techno-economic,Cost estimation

An (MI)LP-based Primal Heuristic for 3-Architecture Connected Facility Location in Urban Access Network Design

We investigate the 3-architecture Connected Facility Location Problem arising in the design of urban telecommunication access networks. We propose an original optimization model for the problem that includes additional variables and constraints to take into account wireless signal coverage. Since the problem can prove challenging even for modern state-of-the art optimization solvers, we propose to solve it by an original primal heuristic which combines a probabilistic fixing procedure, guided by peculiar Linear Programming relaxations, with an exact MIP heuristic, based on a very large neighborhood search. Computational experiments on a set of realistic instances show that our heuristic can find solutions associated with much lower optimality gaps than a state-of-the-art solver.Comment: This is the authors' final version of the paper published in: Squillero G., Burelli P. (eds), EvoApplications 2016: Applications of Evolutionary Computation, LNCS 9597, pp. 283-298, 2016. DOI: 10.1007/978-3-319-31204-0_19. The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-31204-0_1

Scalable dimensioning of resilient Lambda Grids

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Optimization of multiple PON deployment costs and comparison between GPON, XGPON, NGPON2 and UDWDM PON

In this paper we propose an optimization framework for multiple deployment of PON in a wide region with very large number of users, with different bit rate demands, serviced by many central offices, as it may practically happen in a large city that plans a massive introduction of Fiber to the Home technologies using PON. We propose an algorithm called Optimal Topology Search (OTS), which is based on a set of heuristic approaches, capable of performing an optimal dimensioning of multiple PON deployments for a set of central offices (CO), including an optimal distribution of users among the CO. The set of heuristics integrated in OTS permit the efficient clustering of users for each CO, depending on their location and the bit rate demanded by them. It also permits the definition of optimal routes for optical cables and the allocation of branching devices. Taking into account hardware capacity restrictions and physical layer restrictions, we obtained solutions for different types of standardized PON technologies, like GPON, XGPON and NGPON2 as well as for future UDWDM-PON. We evaluate the optimal network deployment in a series of different minimum guaranteed bit rate demand scenarios, employing realistic maps of a large city in order to compare costs and portrait some reference points for deciding in which scenario a specific technology constitutes the best choice

Heuristics for PON-Based 5G Backhaul Design

Small radio cells have been acknowledged as the only technically viable way to provide the individual 100 Mb/s - 1 Gb/s access rates promised by the future 5G* cellular networks. This small-cell approach faces a number of technological challenges when it comes to the design of an appropriate backhaul network. However, not less importantly, it also poses a financial challenge for operators, given the high cost of deployment and maintenance of a large amount of active devices connected at gigabit speeds scattered over a metropolitan area. *In this paper 5G refers to the next generation of cellular networks intended to succeed 3GPP’s LTE advanced.The authors would like to acknowledge the support of projects CRAMnet (MINECO research grant TEC2012-38362-C03-01) and MEDIANET (Community of Madrid research grant S-2009/TIC-1468)

Logical topology design for IP rerouting: ASONs versus static OTNs

IP-based backbone networks are gradually moving to a network model consisting of high-speed routers that are flexibly interconnected by a mesh of light paths set up by an optical transport network that consists of wavelength division multiplexing (WDM) links and optical cross-connects. In such a model, the generalized MPLS protocol suite could provide the IP centric control plane component that will be used to deliver rapid and dynamic circuit provisioning of end-to-end optical light paths between the routers. This is called an automatic switched optical (transport) network (ASON). An ASON enables reconfiguration of the logical IP topology by setting up and tearing down light paths. This allows to up- or downgrade link capacities during a router failure to the capacities needed by the new routing of the affected traffic. Such survivability against (single) IP router failures is cost-effective, as capacity to the IP layer can be provided flexibly when necessary. We present and investigate a logical topology optimization problem that minimizes the total amount or cost of the needed resources (interfaces, wavelengths, WDM line-systems, amplifiers, etc.) in both the IP and the optical layer. A novel optimization aspect in this problem is the possibility, as a result of the ASON, to reuse the physical resources (like interface cards and WDM line-systems) over the different network states (the failure-free and all the router failure scenarios). We devised a simple optimization strategy to investigate the cost of the ASON approach and compare it with other schemes that survive single router failures

Routing cost optimization in Multi Overlay Robust Networks

In the present work we solve the problem of data flow routing in Multi-Overlay Robust Networks (MORN) while aiming to minimize its routing cost. This kind of networks are typically IP/MPLS Data Network deployed over an SDH/DWDM transport infrastructure. Through the IP/MPLSMulti-Layer Data Network different kinds of services having a wide variety of quality of service requirements are delivered. Those services are being transported by an SDH/DWDM Transport Network which has different transport capacities. In this network, routing cost depends not only on the assigned transport capacity but also in the technology that it uses. Our problem seeks not only to route data flows through Data and Transport Networks but also to optimize routing costs and the reliability of the network. The inputs of our problem are the topology of the Data and Transport networks as well as the budget that the network operator has in order to improve its network routing costs and reliability. We will assume that the operator can only use that budget for installing new links between existing transport nodes. The output of the problem is the data flow routing in the Data and Transport Networks and its associated cost. Routing in the Transport Network is calculated not only in the nominal scenario - when all the Transport Network links are up and running - but also in each single transport link failure case.En el presente trabajo se resuelve el problema de rutear flujos de datos en una Red Multi- Capa Robusta (MORN por sus siglas en inglés), mientras que se trata de minimizar el costo asociado a su ruteo. Este tipo de redes son generalmente redes de datos IP/MPLS desplegadas sobre una infraestructura de transporte SDH/DWDM. Sobre la red de datos IP/MPLS se cursan distintos servicios con diferentes requerimientos de calidad de servicio (QoS). Los servicios de la Red de Datos son transportados por la red SDH/DWDM la cual tiene distintas capacidades de transporte. En éste tipo de redes el costo asociado al transporte depende no solo de la capacidad asignada para el transporte sino que también depende de la tecncología utilizada para transportar dicha capacidad. En el problema no sólo se busca enrutar flujos de datos a través de las Redes de Datos y Transporte sino que también se busca optimizar los costos de ruteo y la confiabilidad de la red. Como punto de partida, el problema toma como información la topología de las Redes de Datos y Transporte así como cierto presupuesto que el operador de la red posee para poder mejorar los costos de ruteo y la confiabilidad de su red. Asumiremos que dicho presupuesto solo puede ser utilizado para instalar nuevos enlaces entre los nodos existentes en la Red de Transporte. La salida del problema es el ruteo de los flujos de datos tanto en la Red de Datos como en la de Transporte, así como el costo asociado a dicho ruteo. El ruteo en la Red de Transporte se calcula no solo en el escenario nominal - cuando todos los enlaces de la Red de Transporte están funcionales - sino que también en cada escenario de falla simple en sus enlaces

Lagrangian Decompositions for the Two-Level FTTx Network Design Problem

We consider the design of a passive optical telecommunication access network, where clients have to be connected to an intermediate level of distribution points (DPs) and further on to some central offices (COs) in a tree-like fashion. Each client demands a given number of fiber connections to its CO. Passive optical splitters installed at the DPs allow k connections to share a single common fiber between the DP and the CO. We consider fixed charge costs for the use of an edge of the underlying street network, of a DP, and of a CO and variable costs for installing fibers along the street edges and for installing splitters at the DPs. We present two Lagrangian decomposition approaches that decompose the problem based on the network structure and on the cost structure, respectively. The subproblems are solved using MIP techniques. We report computational results for realistic instances and compare the efficiency of the Lagrangian approaches to the solutions of an integrated MIP model