1) The document presents CSDN, a framework that leverages SDN and NFV to provide network assistance for HTTP adaptive video streaming. It proposes using SDN virtual routers equipped with transcoding capabilities to optimize quality of experience (QoE) based on network conditions and user preferences. 2) An evaluation of CSDN on a testbed with 100 clients showed it improved playback bitrate by 7.5% and reduced quality switches and stalls by 19% compared to state-of-the-art approaches, enhancing user QoE and network utilization. 3) Future work directions include improving edge caching strategies, developing learning-based approaches, and extending an MILP model to optimize transcoding