In the last few years, many new network services have gained much popularity. The most significant examples are cloud computing and content-oriented networking. In more details, the cloud computing has recently evolved from an emerging technology to an recognized networking approach that is gaining extensive acceptance and deployment. According to "Cisco Global Cloud Index" report, the global cloud IP traffic will increase nearly 4-fold from 2013 to 2018 with a CAGR (Compounded Annual Growth Rate) of 32%. Moreover, by 2018 78% of all workloads processed in data centers will be executed in the cloud. In addition, the content-oriented networking approach has been proposed few years ago to facilitate the distribution of various content over the Internet. Cisco in "Cisco Visual Networking Index" report predicts that Content Delivery Networks (CDNs) will carry over 62% of Internet traffic in 2019 compared to 39% in 2014. Both cloud computing and content-oriented services significantly contribute to the overall Internet traffic. Moreover, other bandwidth-hungry applications and services like Internet of Things, Big Data, 5G, are forecasted to additionally increase the number of devices connected to the Internet as well as boost the demand for network bandwidth. Therefore, 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.

Currently, the most popular optical approach is a Wavelength Switched Optical Network (WSON) implemented with the Wavelength Division Multiplexing (WDM) technology, which operates within rigid/fixed frequency grids and with single-line-rate (SLR) transponders making use of single-carrier modulation techniques. However, during the past couple of years, the research in optical networking has experienced significant developments mostly focused on the idea of Elastic Optical Networks (EONs). The main innovation of EON with respect to conventional WSON is the provisioning of sub-wavelength granularity for low-rate transmission and super-channel connectivity for accommodating ultra-high capacity client signals within a common network. The EONs allow to allocate flexibly appropriate-sized optical bandwidth, by means of 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 in the time perspective of 10-20 years, some new advances in optical networks will be required. Space-Division Multiplexing (SDM) technology seems to be an attractive candidate for future optical networks. The main idea behind SDM is to exploit the spatial dimension to provide a significant increase in the transmission system capacity. 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).

The talk will concentrate on the evolution of optical networks and various aspects related to optimization of optical networks. First, the most popular network services will be briefly discussed together with predictions on network traffic. Next, the general idea of Elastic Optical Networks and Space-Division Multiplexing technology will be presented. The main part of the talk will be focused on optimization of EONs in the context of traffic patterns following from cloud computing and content-oriented networking. In more details, various approaches for optimization of EONs will be discussed including ILP (Integer Linear Programming) modeling, heuristic and metaheuristic algorithms. Some illustrating results obtained on real topologies will be reported to show performance of various optimization methods in the context of EONs and to compare EONs against classical WDM networks. Finally, new research challenges that arise in the context of SDM networks will be highlighted.

Biography

Krzysztof Walkowiak received the Ph.D. degree and the D.Sc. (habilitation) degree in computer science from the Wroclaw University of Technology, Poland, in 2000 and 2008, respectively. Currently, he is an Associate Professor at the Department of Systems and Computer Networks, Faculty of Electronics, Wroclaw University of Technology. His research interest is mainly focused on modeling and optimization of communication networks including: elastic optical networks, overlay network, content-oriented networks, survivable networks, distributed computing systems. 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). Moreover, he has been consulting ICT projects for large companies including Ernst and Young, Skanska, TP SA, PZU, PKO BP, Energia Pro, BNP Paribas. Prof. Walkowiak published more than 200 scientific papers including the best 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: http://www.kssk.pwr.edu.pl/walkowiak/?lang=en