Revisiting core traffic growth in the presence of expanding CDNs

Traffic growth forecasts announce a dramatic future for core networks, struggling to keep the pace of traffic augmentation. Internet traffic growth primarily stems from the proliferation of cloud services and the massive amounts of data distributed by the content delivery networks (CDNs) hosting these services. In this paper, we investigate the evolution of core traffic in the presence of growing CDNs. Expanding the capacities of existing data centers (DCs) directly translates the forecasted compound-annual-growth-rate (CAGR) of user traffic to the CAGR of carried core link traffic. On the other hand, expanding CDNs by building new geographically dispersed DCs can significantly reduce the predicted core traffic growth rates by placing content closer to the users. However, reducing DC-to-user traffic by building new DCs comes at a trade-off with increasing inter-DC content synchronization traffic. Thus, the resulting overall core traffic growth will depend on the types of services supported and their associated synchronization requirements. In this paper, we present a long-term evolution study to assess the implications of different CDN expansion strategies on core network traffic growth considering a mix of services in proportions and growth rates corresponding to well-known traffic forecasts. Our simulations indicate that CDNs may have significant incentive to build more DCs, depending on the service types they offer, and that current alarming traffic predictions may be somewhat overestimated in core networks in the presence of expanding CDNs. (C) 2019 The Authors. Published by Elsevier B.V.The research leading to these results has received funding from the European Commission for the H2020-ICT-2016-2 METRO-HAUL project (G.A. 761727) and it has been partially funded by the Spanish national project ONOFRE-2(TEC2017-84423-C3-1-P, MINECO/AEI/FEDER, UE)

Heuristički algoritmi za planiranje virtualnih topologija, usmjeravanje i dodjeljivanje valnih duljina u WDM mrežama

This thesis investigates the problem of designing virtual topologies in wavelength routed WDM (Wavelength Division Multiplex) optical networks. In such networks, a virtual topology is created over the physical optical network by establishing all-optical connections, called lightpaths, between pairs of nodes. Transport via a lightpath is entirely in the optical domain. A virtual topology can also be composed of a set of light-trees which optically connect a subset of nodes in the network. In order to establish a virtual topology, it is necessary to determine a set of lightpaths/light-trees, find for them corresponding paths in the physical topology and assign wavelengths to them. Finally, packet-switched traffic is routed over the virtual topology. The thesis focuses on the problem of routing and assigning wavelengths to lightpaths and light-trees, and the virtual topology design problem in WDM networks. These problems are NP-complete so heuristic algorithms are needed to help solve them. Proposed are efficient heuristic algorithms for the Routing and Wavelength Assignment (RWA) of static and scheduled lightpath demands. Furthermore, developed is a heuristic for multicast routing and algorithms for static multicast RWA. Virtual Topology Design is investigated considering various objective criteria, and an additional objective criterion is proposed. Efficient heuristic algorithms are developed to help solve this problem. To assess the quality of the solutions obtained by the proposed algorithms, new analytical lower bounds for the corresponding problems are developed.Doktorska disertacija istražuje problem planiranja virtualnih topologija u optčkim WDM (Wavelength Division Multiplex) mrežama temeljenim na valnom usmjeravanju. U takvim mrežama, gradi se virtualna topologija nad fizičkom optičkom mrežom uspostavom sve-optičkih kanala, ili svjetlosnih putova, između parova čvorova. Transport po svjetlosnim putovima odvija se isključivo u optičkoj domeni. Virtualna topologija se također može sastojati od skupa svjetlosnih stabala koji sve-optički povezuju skup čvorova. Kako bi se uspostavila virtualna topologija, potrebno je odrediti skup zahtjeva za svjetlosnim putovima/stablima, naći njima odgovarajuće putove u fizičkoj topologiji te im dodijeliti valne duljine. Paketski promet se potom usmjerava kroz uspostavljenu virtualnu topologiju. Istraživanja su fokusirana na problem usmjeravanja i dodjeljivanja valnih duljina svjetlosnim putovima i stablima, te općeniti problem planiranja virtualnih topologija u WDM mrežama. Ovi problemi su NP-potpuni optimizacijski problemi, te su potrebni heuristički algoritmima za njihovo rješavanje. Predloženi su efikasni heuristički algoritmi za probleme usmjeravanja i dodjeljivanja valnih duljina statičkim te raspoređenim zahtjevima za svjetlosnim putovima. Nadalje, razvijen je efikasan heuristički algoritam za višeodredišno usmjeravanje, te heuristike za problem statičkog višeodredišnog usmjeravanja i dodjeljivanja valnih duljina. Istraženo je planiranje virtualnih topologija uzimajući u obzir više ciljeva, te je predložen dodatan kriterij pri planiranju virtualnih topologija. Razvijeni su efikasni heuristicki algoritmi za rješavanje ovog problema. Kako bismo utvrdili kvalitetu rješenja dobivenih predloženim algoritmima, razvijene su nove analitičke donje granice za navedene probleme

Dataset: FPV Drone Control QoE - Quality scores of a subjective study Phase 2

This dataset contains data collected in a subjective study for evaluating Quality of Experience of an FPV drone simulator. The dataset consists of participant demographics, quality scores, and level of simulator sickness symptoms. The data is available as an excel spreadsheet.The findings presented in this dataset are based on two separate subjective studies, referred to as Study 1 and Study 2. The first study was conducted at the University of Zagreb, Faculty of Electrical Engineering and Computing in January of 2021, while the second study was conducted six months later at the University Center of Defence (CUD), San Javier Air Force Base, Spain. A detailed description of the test methodology is given in the following paper: M. Šilić; M. Sužnjević; L. Skorin-Kapov; N. Skorin-Kapov; I. Lorenzana, Marcelo: The Impact of Video Encoding Parameters on QoE of Simulated FPV Drone Control, Multimedia Tools and Applications, 2024, 1-33. DOI: https://doi.org/10.1007/s11042-024-18442-

Attack-aware dedicated path protection in optical networks

Due to the high data rates in optical networks,physical-layer attacks targeting service degradation, such as powerjamming, can potentially lead to large data and revenue losses.Conventional network survivability approaches which establishlink-disjoint working and backup paths to protect from componentfaults may not provide adequate protection for such attacks.Namely, the working and the backup paths, although link-disjoint,might both be affected by a single attack scenario due to specificattack propagation characteristics. To enhance the existing survivabilityapproaches, we utilize the concept of an attack group(AG) which incorporates these characteristics to identify connectionswhich can simultaneously be affected by a single attack. Weapply this concept to dedicated path protection (DPP) and developattack-aware DPP (AA-DPP) approaches which aim to establishAG-disjoint primary and backup paths in a cost-effective manner.We provide a two-step ILP formulation for the routing and wavelengthassignment of the working and backup paths, as well as aheuristic for larger problem instances. Numerical results indicatethat the proposed approaches provide dedicated path protectionschemes with enhanced attack protection without using more resources(i.e., wavelengths, average path lengths) than standardDPPmethods.QC 20160513318137 DISCU