This Recommendation defines the second generation of headend architectures for high-speed data-over-cable systems. The second-generation of headend architecture introduces a number of new features that build upon what was present in previous Cabinet DOCSIS Recommendations [J.223.1] and [J.223.2]. This Recommendation includes key new features for the CMC III Device (also known as the Remote-PHY Device). The second generation Modular Headend Architecture suite of specifications are also known as DOCSIS MHAv2 specifications. This work item plans to endorse as ITU-T Recommendation the following CableLabs standards: [DOCSIS MHAv2 GCP], [DOCSIS RDEPI], [DOCSIS RDTI], [DOCSIS ROOB], [DOCSIS RPHY-OSSI], [DOCSIS RPHY] and [DOCSIS RUEPI].