Recommendation ITU-T G.9961 belongs to the family of ITU-T G.996x Recommendations. Recommendation ITU-T G.9961 specifies the data link layer (DLL) for wireline-based home networking transceivers capable of operating over premises wiring including inside telephone wiring, coaxial cable, and power-line wiring. It complements the system architecture and physical (PHY) layer specification in Recommendation ITU-T G.9960, and the power spectral density (PSD) specification in Recommendation ITU-T G.9964. Amendment 1 includes a new physical layer specification. This new physical layer provides new modulation mechanisms (e.g. Multi Level Coding) and Robust Communication Mode (RCM) and allows the system to be operated over an extended bandwidth for coaxial and phoneline mediums. Amendment 2 includes a new Annex D on IEEE 802.1X port-based network access control, means for delivering management data across the A interface, and support for a wider range of applications of the G.hn technology (e.g., means to indicate the category of applications and actual application that the domain is implementing). Amendment 3 includes enhancements to simplify routing mechanisms in tree topologies.