A RMSA algorithm resilient to multiple node failures on elastic optical networks

An Elastic Optical Network (EON) provides a lot of flexibility on the way an optical network supports the demands of multiple services. This flexibility is given by the Routing, Modulation and Spectrum Assignment (RMSA) algorithm whose primary goal is to use the spectrum resources of the network in an efficient way. Recently, large-scale failures are becoming a concern and one source of such failures is malicious human activities. In terrorist attacks, although node shutdowns are harder to realize than link cuts, they are the most rewarding in the attackers’ perspective since the shutdown of one node also shuts down all its connected links. In order to obtain a RMSA algorithm resilient to multiple node failures, we propose the use of a path disaster availability metric which measures the probability of each path not being affected by a multiple node failure. We present computational results considering a mix of unicast and anycast services in 3 well-known topologies. We assess the trade-off between spectrum usage efficiency and resilience to multiple node failures of our proposal against other previous known algorithms. The results show that the RMSA decision is always better when the disaster path availability metric is used. Moreover, the best way to use the path disaster availability metric in the RMSA decision depends on the traffic load of the EON.publishe

RMSA algorithms resilient to multiple node failures in dynamic EONs

In Elastic Optical Networks (EONs), the way different service demands are supported in the network is ruled by the Routing, Modulation and Spectrum Assignment (RMSA) algorithm, which decides how the spectrum resources of the optical network are assigned to each service demand. In a dynamic EON, demand requests arrive randomly one at a time and the accepted demands last in the network for a random time duration. So, one important goal of the RMSA algorithm is the efficient use of the spectrum resources to maximize the acceptance probability of future demand requests. On the other hand, multiple failure events are becoming a concern to network operators as such events are becoming more frequent in time. In this work, we consider the case of multiple node failure events caused by malicious attacks against network nodes. In order to obtain RMSA algorithms resilient to such events, a path disaster availability metric was recently proposed which takes into account the probability of each path not being disrupted by an attack. This metric was proposed in the offline variant of the RMSA problem where all demands are assumed to be known at the beginning. Here, we exploit the use of the path disaster availability metric in the RMSA of dynamic EONs. In particular, we propose RMSA algorithms combining the path disaster availability metric with spectrum usage metrics in a dynamic way based on the network load level. The aim is that the efficient use of the resources is relaxed for improved resilience to multiple node failures when the EON is lightly loaded, while it becomes the most important goal when the EON becomes heavily loaded. We present simulation results considering a mix of unicast and anycast services in 3 well-known topologies. The results show that the RMSA algorithms combining the path disaster availability metric with spectrum usage metrics are the best trade-off between spectrum usage efficiency and resilience to multiple node failures.publishe

Meta Heuristic Algorithms for Routing and Spectrum Assignment in Elastic Optical Networks

The day to day improvement of bandwidth hungry applications such as video streaming, video gaming and many more has lead to more stringent requirements on networks. These requirements have generated a significant shift from the traditional fixed-grid Wavelength Division Multiplexing (WDM) networks to flexible-grid Elastic Optical networks (EONs). Flexible-grid EONs have brought in new ways for allocating spectrum in an efficient manner. Unfortunately, they have also brought in new challenges with respect to spectrum allocation. It is much more complex to grant demands in flexible-grid EONs, as they take into account more constraints than traditional fixed-grid WDM networks. Despite the effort that has been made by the research community to handle those constraints separately, very little has been done tackling them simultaneously, and under realistic scenarios. In this thesis, we propose two meta-heuristic algorithms for allocating demands in flexible grid EONs while simultaneously taking into accounts all the constraints. Our algorithms are tested on small and large networks, with heavy load. Experimental results show that our algorithms perform quite well on all the instances that were selected

Artificial intelligence (AI) methods in optical networks: A comprehensive survey

Producción CientíficaArtificial intelligence (AI) is an extensive scientific discipline which enables computer systems to solve problems by emulating complex biological processes such as learning, reasoning and self-correction. This paper presents a comprehensive review of the application of AI techniques for improving performance of optical communication systems and networks. The use of AI-based techniques is first studied in applications related to optical transmission, ranging from the characterization and operation of network components to performance monitoring, mitigation of nonlinearities, and quality of transmission estimation. Then, applications related to optical network control and management are also reviewed, including topics like optical network planning and operation in both transport and access networks. Finally, the paper also presents a summary of opportunities and challenges in optical networking where AI is expected to play a key role in the near future.Ministerio de Economía, Industria y Competitividad (Project EC2014-53071-C3-2-P, TEC2015-71932-REDT

Exhaustive Search for Optimal Offline Spectrum Assignment in Elastic Optical Networks

Heuristic-based approaches are widely deployed in solving Spectrum Assignment problem. This causes the results to be unreliable in some test cases when the results are very far from the lowerbound. This paper presents an exhaustive search approach that starts with an initial seed of a solution achieved by a heuristic-based algorithm called “Longest First Fit” (LFF) and tries all possible permutations starting from this initial seed. The algorithm skips some branches and all its descendant permutations if it meets certain criteria that guarantees that those permutations will not lead to a better result. The experimental results show that the new algorithm has succeeded in achieving the lower-bound in 93% of the randomly generated test cases while the heuristic solver LFF can achieve 65%. The algorithm achieves these results in a reasonable running time of less than 10 seconds

Routing, Modulation and Spectrum Assignment Algorithm Using Multi-Path Routing and Best-Fit

Producción CientíficaElastic Optical Networks (EONs) are a promising optical technology to deal with the ever-increasing traffic and the vast number of connected devices of the next generation of the Internet, associated to paradigms like the Internet of Things (IoT), the Tactile Internet or the Industry 4.0, to name just a few. In this kind of optical network, each optical circuit or lightpath is provisioned by means of superchannels of variable bandwidth. In this manner, only the necessary bandwidth to accommodate the demand is allocated, improving the spectrum usage. When establishing a connection, the EON control layer determines the modulation format to be used and allocates a portion of the spectrum in a sequence of fibers from the source to the destination node providing the user-demanded bandwidth. This is known as the routing, modulation level and spectrum assignment (RMSA) problem. In this work, we firstly review the most important contributions in that area, and then, we propose a novel RMSA algorithm, multi-path best-fit (MP-BF), which uses a split spectrum multi-path strategy together with a spectrum assignment technique (best-fit), and which jointly exploit the flexibility of EONs. A simulation study has been conducted comparing the performance of EONs when using MP-BF with other proposals from the literature. The results of this study show that, by using MP-BF, the network can increase its performance in terms of lightpath request blocking ratio and supported traffic load, without affecting the energy per bit or the computation time required to find a solution

Evaluation and design of elastic optical networks resilient to multiple node failures

Consider an existing Elastic Optical Network (EON) with a given topology composed by nodes and connecting fibers, each fiber with a given spectrum capacity. Consider an estimated set of demands to be supported and a routing, modulation and spectrum assignment (RMSA) policy adopted by the operator both for the regular state and for the failure states. First, we address the resilience evaluation of the EON to multiple node failures. We adopt a worst-case approach by identifying the nodes (named critical nodes) whose simultaneous failure maximally reduce the demand percentage that is supported by the network and we use this percentage as the resilience metric. Then, for the same estimated demands, the same RMSA policy and a fiber budget equal to the total fiber length of the existing network, we address the design problem aiming to determine a new EON maximizing the resilience metric imposed by its critical nodes. We use a multi-start greedy randomized method that generates multiple EONs and returns the best one, i.e., the EON with the highest resilience metric. We run the evaluation and design methods on known network topologies. The computational results let us (i) analyze the efficiency of the methods and (ii) assess how far the resilience of existing networks are from the best ones.This paper is based upon work from COST Action CA15127 (”Resilient communication services protecting end-user appli- cations from disaster-based failures – RECODIS”) supported by COST (European Cooperation in Science and Technology). The work was also supported by FCT, Portugal, through project ResNeD CENTRO-01-0145-FEDER-029312 and PhD grant SFRH/BD/132650/2017. Second and third authors were supported by FCT through projects UID/EEA/50008/2019 and UID/MAT/04106/2019, respectively.publishe

Models of vertical interconnection in the future internet networks

Interkonekcija, čiji primarni cilj je omogućavanje korisnicima jednog učesnika na tržištu telekomunikacija da komuniciraju sa korisnicima drugog učesnika, odnosno, obezbeđivanje pristupa servisima koje obezbeđuje drugi učesnik, javila se nakon liberalizacije tržišta telekomunikacija. Vertikalna interkonekcija predstavlja fizičko i logičko povezivanje učesnika na različitim nivoima mreže. U okruženju budućeg Interneta, sagledavanje tehničko-ekonomskih aspekata interkonekcije predstavlja pitanje od izuzetnog značaja. U opštem slučaju, učesnici u vertikalnoj interkonekciji u okruženju budućeg Interneta mogu biti provajderi sadržaja i aplikacija, provajderi Internet servisa, Content Delivery Network (CDN) provajderi i cloud provajderi. Pojava Cloud Computing-a uvela je značajne promene u Internet okruženju koje se pre svega odnose na mogućnost pristupa skalabilnim i deljivim, fizičkim ili virtuelnim resursima. Na taj način, stvara se elastična platforma koja obezbeđuje dinamičnu i jednostavnu skalabilnost, pojednostavljuje se obezbeđivanje infrastrukture i omogućava se unapređenje performansi. Razvoj servisa i aplikacija zahtevnih u pogledu propusnog opsega praćen širom implementacijom Cloud Computing-a utiče na kontinuiran rast Internet saobraćaja, što zahteva primenu tehnologija koje mogu zadovoljiti sve strože zahteve. Kao rešenje za transportni nivo mreže, razvijene su elastične optičke mreže koje mogu obezbediti dovoljne propusne opsege uz efikasno iskorišćenje spektra. Imajući u vidu promene koje prate razvoj okruženja budućeg Interneta, kao i značaj vertikalne interkonekcije, neophodno je razmotriti i jasno definisati tehničko-ekonomske relacije između učesnika u budućem Internetu, što je predmet istraživanja ove doktorske disertacije. U okviru disertacije predložen je model koji ima za cilj određivanje adekvatnog ugovora o interkonekciji između učesnika u vertikalnoj interkonekciji, i to provajdera sadržaja i aplikacija i provajdera Internet servisa u procesu obezbeđivanja sadržaja krajnjim korisnicima, uz mogućnost parcijalne migracije sadržaja na resurse cloud provajdera. Analiza obuhvata različite ugovore o interkonekciji i određuje adekvatan ugovor, u zavisnosti od ciljnih profita provajdera koji učestvuju u vertikalnoj interkonekciji i prihvatljive stope odbijenih zahteva za obezbeđivanje sadržaja krajnjim korisnicima. Data analiza je proširena istraživanjem adekvatnog mehanizma tarifiranja i alokacije resursa cloud provajdera. Predložen je nov, hibridni model pristupa resursima cloud provajdera koji obezbeđuje zadovoljavajuće rezultate u kontekstu minimizacije troškova i minimizacije stope odbijenih zahteva za pristup sadržajima...Interconnection, whose primary aim is enabling communication between end users of different undertakings, i.e. enabling access to the other undertaking's services, was introduced after the telecommunication market liberalization. Vertical interconnection represents the physical and logical linking of the undertakings on different network levels. Consideration of technical and economic aspects of the interconnection is a crucial issue in the future Internet environment. In general, undertakings in vertical interconnection in the future Internet environment include content and application providers, Internet service providers, Content Delivery Network (CDN) providers and Cloud providers. The development of Cloud Computing introduced significant changes in the Internet environment in terms of enabling access to scalable and shareable, physical or virtual resources. Therefore, the elastic platform for dynamic and simple scalability is enabled, the access to infrastructure is simplified and performances are improved. High bandwidth demanding services and applications, along with the wide adoption of Cloud Computing causes permanent growth of Internet traffic. This indicates that the introduction of new technologies, capable to satisfy high bandwidth requirements, is necessary. Elastic optical networks are proposed as a promising solution for transport networks. These networks provide enough bandwidth, along with high efficiency in spectrum utilization. Forasmuch changes in the future Internet environment and the importance of the vertical interconnection, it is mandatory to consider and properly define technical and economic relations between undertakings in the future Internet environment, which is the research subject of this doctoral dissertation. Within dissertation, a model for the determination of a proper interconnection agreement between undertakings in the vertical interconnection, content and application provider and an Internet service provider, in the content provisioning process with partial cloud migration is proposed. The analysis comprises different interconnection agreements and determines appropriate agreement, depending on the targeted providers' profits and satisfying requests' for content provisioning rejection rate. This analysis is extended to determine adequate pricing and allocation mechanism for cloud provider's resources. A new, hybrid model for enabling access to cloud resources is proposed. The model provides satisfying results in terms of the costs' minimization and the minimization of requests' rejection rate..

Mobile Ad Hoc Networks

Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms