We present an optimization procedure that mixes advanced large-scale methods and heuristics to solve large instances (with over 1.7 million integer variables) of the routing spectrum allocation (RSA) problem — a basic in flexgrid elastic optical networks. formulate as mixed-integer program for which we develop branch-and-price algorithm enhanced with such techniques relaxations cuts improving lower bounds (LBs) optimal objective value, RSA heuristic upper bounds. All these elements are...

This work presents an on-line, energy- and communication-aware scheduling strategy for SaaS applications in data centers. The are composed of various services represented as workflows. Each workflow consists tasks related to each other by precedence constraints Directed Acyclic Graphs (DAGs). proposed combines advantages state-of-the-art strategies with energy-aware independent task approaches. process two phases. In the first phase, virtual deadlines individual set central scheduler. These...

Ultra-wideband wavelength division multiplexed networks enable operators to use more effectively the bandwidth offered by a single fiber pair and thus make significant savings, both in operational capital expenditures. The main objective of this study is minimize optical node resources, such as transponders, multiplexers selective switches, needed provide maintain high quality network services, ultra-wideband networks, at low cost. A model based on integer programming proposed, which...

New generation of optical nodes in dense wavelength division multiplexed networks enables operators to improve service flexibility and make significant savings, both operational capital expenditures. Thus the main objective study is minimize node resources, such as transponders, multiplexers selective switches, needed provide maintain high quality network services using new nodes. A model based on integer programming proposed, which includes a detailed description an node. The impact...

In the paper we consider a flow problem closely related to path diversity protection in communication networks. Given weighted directed graph where some arcs are subject failures while others resilient, aim at computing shortest pair of failure-disjoint paths. If resilient arc is used by both paths, its cost counted only once. We present an original polynomial-time algorithm for solving problem.

In dynamic flexgrid optical networks, the usage of capacity may not be optimal due to permanent process setting up and tearing down connections, which, if controlled, leads spectrum fragmentation and, as a result, increase connection blocking. On top this, restoration mechanism that is launched in reaction link failure (cable cut) restores affected lightpaths. Eventually, when cable repaired its becomes available for new unbalance between lightly heavily loaded links increases, thus further...

Abstract In this article we prove 𝒩𝒫‐hardness of two well‐known optimization problems related to the design multicommodity flow networks with different methods for providing network resiliency against failures: path diversity and restoration. Path is a static mechanism that consists using, each demand, number paths oversizing flows assigned these so any failure total surviving not less than volume demand. By contrast, restoration dynamic reassigning failed backup when occurs. Both mechanisms...

We present an optimization platform for Fiber-to-the-Home network design. The is capable of minimizing the capital expenditures (CAPEX) deployment by optimizing locations optical equipment, signal splitters and cable cabinets, routes types cables as well number cards splitters. architecture platform, design process it implements, algorithms deploys. used to indicate parts that require complex with dedicated those can be left appropriately crafted engineering rules. while keeping computation...

We deal with a natural integer-linear programming formulation of the routing and spectrum allocation (RSA) problem in elastic optical networks. focus on strengthening valid inequalities (cuts). For this purpose we apply clique that proved to be useful other applications kind. develop combine cut generation procedure column algorithm aim improve quality generated columns. The presented results, obtained for set instances, illustrate effectiveness optimization algorithm.

The subject of the study was an application nature-inspired metaheuristic algorithms to node configuration optimization in optical networks. main objective minimize capital expenditure, which includes costs resources, such as transponders and amplifiers used a new generation For this purpose model that takes into account physical phenomena network is proposed. Selected were implemented compared with reference, deterministic algorithm, based on linear integer programming. cases studied...

In the paper we present integer programming (IP) optimization models for flexgrid elastic optical networks (EON). We consider several different basic assumptions regarding flexibility of EON that lead to a variety IP formulations differing in precision and complexity. As usual, detailed aiming at precisely describing technological aspects suffer from tractability issues resulting their greater complexity have be reasonably simplified. To achieve this, cases where bandwidth is divided into...

The NFV is focused at virtualizing network functions such as gateways, path computing devices, resource allocation mechanisms, proxies, firewalls and transcoders, traditionally carried out by specialized hardware migrating these to software-based appliances. In this paper, an analytic model for the forwarding graph proposed with aim optimize execution time of services deployed.

In the paper we present a branch and price approach to routing spectrum allocation - basic optimization problem in elastic optical networks. We formulate as mixed-integer program for which develop algorithm enhanced with such techniques cutting planes improving lower bounds optimal objective value, greedy simulated annealing heuristics upper bounds. All these elements are combined into an effective procedure. Preliminary results show that is able produce solutions vast majority of considered...

In flexgrid-based optical networks, the problem of finding optimal route and spectrum allocation (RSA) for demands in a traffic matrix becomes harder to solve than similar problems fixed DWDM mainly due finer granularity contiguity continuity constraints. Additionally, increasing volumes size real networks lead network planning instances consisting hundreds thousands, or even millions, (binary) variables. this work, we present column generation decomposition method obtain feasible solutions...

We consider linear programs involving uncertain parameters and propose a new tractable robust counterpart which contains generalizes several other models including the existing Affinely Adjustable Robust Counterpart Fully Counterpart. It consists in selecting set of poles whose convex hull some projection uncertainty set, computing recourse strategy for each data scenario as combination optimized recourses (one pole). show that proposed multipolar is its complexity controllable. Further, we...

In the paper we deal with problem of optimal partitioning a traffic demand polytope using hyperplane. considered model all possible matrices belong to polytope. The can be divided into parts, and different routing schemes while dealing from parts applied networks that support unrestricted bifurcated flows, e.g., MPLS or optical networks. present an algorithm solves one most practical versions problem, i.e., reservation vectors on both sides hyperplane have same. Moreover, another (faster)...

In this paper, a problem of rational splitter and OLT card installation in fiber-to-the-home (FTTH) networks is considered. We assume that the most tedious part FTTH network deployment, i.e., trenching cable installation, completed, operator can start to connect customers network. The connecting process still requires expenditures for both passive (splitters) active (ONUs, cards) equipment. we define deployment present multi-state optimization (MuSO) approach handle it. MuSO minimizes...

In this research, we analyse the impact of various uncertainty models describing clients' behaviour on optimal FTTH network designs. We introduce models, optimize designs taking into account introduced and evaluate those against different plausible scenarios behaviour. The research is intended to show advantages weaknesses in field design.

In the paper we present NG_ROADM Optical Node Architecture and particularly concentrate on optimization of optical node resources (i.e., various types transponders). The main objective is to minimize capex opex in real telco service providers networks. We formulate problem as mixed integer linear programming. results numerical experiments run network topologies different dimensions with large demand set. For this purpose develop specifically tailored algorithm based

The paper is devoted to modeling and optimization of reliable wireless mesh networks that employ directional antennas. We introduce two mixed-integer programming formulations allow simultaneously characterize routing patterns transmission schedules. first model allows for maximizing the minimal flow in a network. second involves reliability constraints aims at minimizing number used In both cases locations routers are known. However, installed radio interfaces their directions subject...