Overlay routing in Content Distribution Networks for Quality of Experience optimization

The constantly increasing amount of video traffic is a challenge for service providers that need to maximize Quality of Experience (QoE) while optimizing the cost of their infrastructure. In this thesis, we address the problem of routing multiple HTTP-based Adaptive Streaming (HAS) sessions to maximize QoE. We first design a model linking the Quality of Service (QoS) Metrics to a single QoE score. This QoS-QoE model incorporates different QoE metrics and is able to learn online network variations and predict their impact on representative classes of adaptation logic, video motion and client resolution. Different QoE metrics are then combined into a QoE score based on ITU-T Rec. P.1202.2. This rich score is used to formulate the routing problem. We show that, even with a piece-wise linear QoE function in the objective, the routing problem without controlled rate allocation is non-linear. We therefore express a routing-plus-rate allocation problem and make it scalable with a dual subgradient approach based on Lagrangian relaxation where subproblems select a single path for each request with a trivial search, thereby connecting explicitly QoE, QoE and HAS bitrate. We show with ns-3 simulations that our algorithm provides values for HAS QoE metrics (quality, rebufferings, variation) equivalent to MILP and better than QoS-based approaches. Since ns-3 simulator cannot take in account different traffic queues for the same link we have then designed an emulated SDN solution based on a virtual switch with a virtual remote network controller and multiple lightweight clients to analyze the network behavior in the single bottleneck case

La circolazione dello status dei minori attraverso le «frontiere» d’Europa: intersezioni tra diritto dell’Unione e diritto internazionale privato alla luce della sentenza Pancharevo

L’articolo muove dalla decisione resa dalla Corte di giustizia dell’Unione europea nel caso Pancharevo per riflettere intorno alle ricadute nel quadro della circolazione intraeuropea degli status di figli creati all’estero sul piano del diritto sostanziale dell’Unione europea e del diritto internazionale privato e si avvale anche della prospettiva pratica di chi, come l’ufficiale di stato civile e il notaio, sono impegnati con il riconoscimento di status personali e familiari e le rispettive implicazioni nello Stato membro richiesto. Lo scritto trae spunto dalle riflessioni maturate dagli autori nell’ambito della conferenza finale del progetto DxB “Identities on the move - Documents cross borders” finanziato dalla Commissione europea (23-24 giugno 2022)

Quality of Experience-based Routing of Video Traffic for Overlay and ISP Networks

International audienc

Appendices on QoE model and DASH manifest in "Quality of Experience-based Routing of Video Traffic for Overlay and ISP Networks"

This report provides the details about (i) the QoE-QoS model and (ii) the DASH representations used in the simulations performed in [2]. The report details the calculations required to find a concave Quality of Experience (QoE) curve from Quality of Service (QoS) metrics by using the reference model of ITU-T Rec. P.1202.2 [3], [6], the calibration and linearization of such QoE curve; and, the Dynamic Adaptive Streaming over HTTP (DASH) representations used in the paper simulations