NoF 2018

9th International Conference on Network of the Future
November 19-21, 2018
Poznań, Poland

Tutorials NoF 2018

Title: Spectrally-spatially flexible optical networks: technology and optimization

Abstract: Network traffic has been consistently growing at a huge speed over last few decades and across various networks, from the optical core to fixed and mobile access. The major reason behind this increase is due to the advent of services, applications and technologies including cloud computing, content-oriented networking, Internet of Things and 5G. Consequently, to overcome the possible future capacity crunch, new network technologies are required with a special focus on optical networks that are implemented in backbone networks. At this time, there are two popular optical approaches utilized in backbone optical networks: long-established Wavelength Switched Optical Network (WSON) implemented with the Wavelength Division Multiplexing (WDM) technology and more recent Elastic Optical Network (EON). The key difference between WSONs and EONs is the use of frequency grid. In particular, WSONs operate within rigid/fixed frequency grids with 50 GHz spacing and with single‐line‐rate (SLR) transponders making use of single-carrier modulation techniques. In turn, EONs utilize flexible frequency grids, where the spectrum resources are divided into narrow frequency slices of 12.5 GHz, what allows to allocate flexibly appropriate-sized optical bandwidth, by means of a contiguous concatenation of optical spectrum, to an end-to-end lightpath and according to traffic demand. Moreover, EONs enable the application of advanced and spectrally‐efficient modulation formats. As a consequence, the EONs utilize network resources more efficiently and, at the same time, they provide network connectivity adaptively and according to bandwidth demands. However, due to the predicted traffic growth and the possibility of the capacity crunch in the time perspective of next years, some new concepts and ideas are indispensable in optical networks. Space division multiplexing (SDM) is a new optical network technology that goes beyond the capabilities of spectrally-flexible EONs by supporting parallel transmission of several co- propagating spatial modes in suitably designed optical fibers. The simplest version of SDM assumes a use of fiber-bundles composed of physically-independent, single-mode fibers. More advanced SDM deployments will be based on multicore fibers (MCF) or multimode fibers (MMF). Spectrally-spatially flexible optical networks (SS-FONs), which combine SDM with EON technologies, bring many benefits including an enormous increase in transmission capacity, extended flexibility in resource management due to the introduction of the spatial domain, as well as potential cost savings thanks to the sharing of resources and the use of integrated devices.

The tutorial will concentrate on spectrally-spatially flexible optical networks with a special focus of two aspects: technology and optimization. First, the general idea of the SS-FONs technology will be explained including details on both Elastic Optical Networks and Space-Division Multiplexing technologies. Practical issues related to hardware and software solutions will be discussed including: fibers, crosstalk, transponders, switching architectures and control plane. The second part of the talk will be focused on optimization of spectrally-spatially flexible optical networks. In particular, the basic optimization problem in SS-FONs, namely Routing, Space and Spectrum Allocation (RSSA) problem will be formulated and analyzed. Various approaches for solving the RSSA problem will be described including ILP (Integer Linear Programming) modeling, heuristic and metaheuristic algorithms. Some illustrating results obtained on real topologies will be reported. The key performance metrics that must be addressed in optimization of SS-FONs will be examined, namely, spectrum usage, CAPEX cost, energy consumption, spectrum fragmentation. Moreover, issues related to modeling and optimization of various traffic patterns following from cloud computing and content-oriented networking as well as aspects of network resilience will be discussed. The last part of the talk will be focused on new research challenges that arise in the context of SS-FONs.


Speaker

Krzysztof Walkowiak

Krzysztof Walkowiak
(Wroclaw University of Science and Technology, Poland)

Biography: Krzysztof Walkowiak received the Ph.D. degree and the D.Sc. (habilitation) degree in computer science from the Wroclaw University of Science and Technology, Poland, in 2000 and 2008, respectively. In 2017, he received the professor title in technical science from President of Poland. Currently, he is working as a Full Professor at the Department of Systems and Computer Networks, Faculty of Electronics, Wroclaw University of Science and Technology. His research interest is mainly focused on modeling and optimization of communication networks including: elastic optical networks, cognitive optical networks, cloud computing, overlay networks, content-oriented networks, survivable networks. Prof. Walkowiak has been involved in many research projects related to optimization of communication networks. He received the 2014 Fabio Neri Best Paper Award, Best Paper Award in the 7th International Workshop on Design of Reliable Communication Networks (DRCN 2009), Best Paper Award in the 7th International Workshop on Reliable Networks Design and Modeling (RNDM 2015). Prof. Walkowiak published more than 250 scientific papers including over 50 papers in JCR journals, in the field of optimization and modeling of communication networks. He is an Associate Editor of the Journal of Network and Systems Management and he serves as a reviewer for many international journals and conferences. Prof. Walkowiak is a senior member of IEEE and ComSoc. Web page: https://www.kssk.pwr.edu.pl/people/walkowiak Piotr Lechowicz received his M.S. degree in computer science from the Wroclaw University of Science and Technology, Poland, in 2016. He is currently working toward his Ph.D. degree in computer science in the Department of Systems and Computer Networks, Faculty of Electronics, Wroclaw University of Science and Technology. His research interests include modeling and optimization of spectrally-spatially flexible optical networks.


Key dates

  • Paper Submission Due
    July 24, 2018 (extended)
  • Paper Review Feedback
    September 21, 2018
  • Final Papers Due
    October 05, 2018
  • Conference
    November 19-21, 2018

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