A Multi-Tier Fog Content Orchestrator Mechanism with Quality of Experience Support
Video-on-Demand (VoD) services create a demand for content orchestrator mechanisms to support Quality of Experience (QoE). Fog computing brings benefits for enhancing the QoE for VoD services by caching the content closer to the user in a multi-tier fog architecture, considering their available resources to improve QoE. In this context, it is mandatory to consider network, fog node, and user metrics to choose an appropriate fog node to distribute videos with QoE support properly. In this
... , we introduce a content orchestrator mechanism, called of Fog4Video, which chooses an appropriate fog node to download video content. The mechanism considers the available bandwidth, delay, and cost, besides the QoE metrics for VoD, namely number of stalls and stalls duration, to deploy VoD services in the opportune fog node. Decision-making acknowledges periodical reports of QoE from the clients to assess the video streaming from each fog node. These values serve as inputs for a real-time Analytic Hierarchy Process method to compute the influence factor for each parameter and compute the QoE improvement potential of the fog node. Fog4Video is executed in fog nodes organized in multiple tiers, having different characteristics to provide VoD services. Simulation results demonstrate that Fog4Video transmits adapted videos with 30% higher QoE and reduced monetary cost up to 24% than other content request mechanisms. (D. Alencar), firstname.lastname@example.org (R. Meneguette), email@example.com (D. Rosário), firstname.lastname@example.org (J. Nobre), email@example.com (C. Both), firstname.lastname@example.org (E. Cerqueira), email@example.com (T. Braun). traffic for delivery content with smoother playback. However, users end up abandoning the service due to stalls, rebufferings, playback average, and bitrate variability [2, 5] . In the last few years, caching services and fog computing have gained a lot of attention in both industry and academia as new schemes to improve the VoD delivery to mobile users  . Fog computing extends cloud computing services with (ultra) low latency, and additional computing, storage, and networking resources closer to the user. Fog computing offers VoD services cached closer to the user, providing the transmission requirements properly in terms of delay and bandwidth  . In this sense, a multi-tier fog computing environment enables to execute VoD services at each level to match the topology and distributed workload properties of VoD applications, while meeting QoE requirements  . However, how, where, and when to orchestrate the usage of fog nodes for VoD services in a multi-tier fog computing scenario is not a trivial task and it is still an open issue  .