On the benefits and caveats of exploiting Quality on Demand Network APIs for video streaming

The mobile industry - via forums such as the O-RAN Alliance and Linux Foundation CAMARA - is working on network APIs that allow a mobile network operator to expose network capabilities to application developers. One of these APIs is the Quality on Demand (QoD) API, which enables the application to ask for additional network resources for improved latency or bandwidth. In this work, we show how an intelligent content delivery network (CDN) can exploit these APIs to improve the quality of experience (QoE) of video streaming despite difficult network conditions by boosting the available network bandwidth at precise moments in time. As the bandwidth boost is only applied whenever necessary, we avoid the caveat of constantly and statically assigning network resources to a service. We propose two boosting strategies both relying on information provided by the video player via Common Media Client Data (CMCD). We implemented the approach and evaluated it on an emulation testbed and on top of an actual 5G O-RAN compliant network capable of running xApps and the CAMARA QoD API. Our evaluation shows the gains in terms of QoE but also highlights possible caveats and adverse interactions with the ABR algorithm of the video player.