Which technologies are highlighted in DOCSIS 4.0 for sustaining HFC networks?

The correct answer emphasizes Full Duplex DOCSIS (FDX) and Extended Spectrum DOCSIS (ESD) as key technologies in DOCSIS 4.0 for sustaining Hybrid Fiber-Coaxial (HFC) networks. Full Duplex DOCSIS allows for simultaneous data transmission and reception over the same frequency spectrum, effectively doubling the potential capacity of existing networks without requiring additional infrastructure. This is particularly significant for improving upstream bandwidth, which has become increasingly important as demand for upload speeds rises.

Extended Spectrum DOCSIS builds upon existing technologies by utilizing a wider range of frequency spectrum, thereby enabling greater throughput. This approach is designed to optimize the use of available bandwidth, addressing the growing needs for higher data rates due to increased consumption of high-definition video, online gaming, and other bandwidth-intensive applications.

The other options do not pertain to DOCSIS 4.0 or HFC network enhancement in a relevant way. Hybrid Ethernet and Point-to-Point protocols are more aligned with IP-based networks rather than the specific enhancements brought by DOCSIS. Basic Rate Interface (BRI) and Frame Relay, as well as Advanced Digital Subscriber Line (ADSL) and Synchronous Optical Networking (SONET), do not focus on the cable broadband standards