By Asaf Matatyaou, Harmonic, Inc.; Brian Bendt, Comporium
The promise and potential of virtualizing a cable hub has been discussed over the past few years. There are many opportunities when discussing virtualization. In 2018, Harmonic presented one possible starting point, by virtualizing a CMTS in a centralized deployment model in a headend or hub. The focus of this paper will be specific to a Distributed Access Architecture (DAA) deployment, leveraging the same approach of virtualizing the CMTS.
While the benefits and general considerations of a virtualized CMTS (vCMTS) have been described in past technical papers, this paper will focus on real-world experiences and lessons learned deploying avCMTS in a DAA. The combination of virtualization and the use of Remote PHY as a protocol between avCMTS Core in a centralized facility and distributed Remote PHY Devices (RPDs), when migrating from a hardware-based CMTS deployed on a traditional HFC infrastructure, will be described. Important areas of consideration when deploying DAA will include usage of IEEE-1588 over aware and unaware networks, as well as the Converged Interconnect Network (CIN) connecting the vCMTS with the RPDs.
Supporting legacy services, such as video and out-of-band, and operational aspects necessary to field deploy DAA, such as leakage and upstream spectrum, will be described. The paper will also examine the differences between DAA and a traditional HFC deployment, where the RF is generated in the headend or hub in comparison to the Remote PHY node. Lastly, the usage of streaming telemetry will be explored in comparison to legacy monitoring techniques, paying particular attention to important metrics that are gathered by the RPDs.