By Alon Bernstein, Pawel Sowinski, Cisco Systems, Inc.
Robust and granular QoS support is a key factor in the tremendous success DOCSIS has achieved as a mature technology in delivery of data, voice and video services. The basic DOCSIS QoS architecture is built upon the foundation of the service flow concept that has been defined fourteen years ago as part of DOCSIS 1.1. The fundamental DOCSIS QoS framework has remained mostly unchanged since then.
Recently, as part of the industry dialog leading to CCAP and DOCSIS 3.1, cable operators have requested to apply QoS policies to aggregation of service flows in addition to individual service flow QoS. The paper presents a case for extending DOCSIS to include elements of hierarchical QoS (HQoS) technology for this purpose. While HQoS techniques have been deployed in other broadband access technologies, integration of HQoS with DOCSIS has never been attempted before. Such integration poses a number of unique technical and business challenges that deserve careful examination. Through the review of typical use case examples, the paper examines how the HQoS technology provides the business value to the cable operators in extending services to gigabit and beyond.
Finally, the paper explores a set of issues and potential solutions imperative to enable seamless integration of hierarchical QoS into CCAP deployments and to facilitate rudimentary multi-vendor interoperability, including necessary signaling protocol and elements of standard CMTS/CCAP configuration.