By Xiaomei Liu, Cisco Systems
Cable operators are increasingly embracing a new wave of video delivery to extend video services to multiple screens and off-net subscribers. The latest and the most important technology breakthrough to enable this new paradigm of video delivery is adaptive streaming. With wide support on client devices, adaptive streaming holds the promise of a unified video service delivery architecture for unmanaged devices and off-net subscribers. Adaptive streaming successfully tackles the challenges of delivering video services over unmanaged networks. However, delivering video services using adaptive streaming at scale in managed cable networks is demanding.
This paper examines various technical challenges of adaptive streaming in managed cable access networks and then explores a variety of optimization options. It proposes upstream optimization with TCP ACK QoS prioritization and TCP ACK suppression in addition to simple upstream bandwidth expansion. For downstream optimization, the coupling of VBR video and adaptive streaming is proposed to reduce downstream bandwidth consumption and to improve video quality significantly. Finally, a flexible downstream QoS design with bandwidth protection, stream prioritization and video quality optimization is introduced.