ITU-T Recommendation G.9954 defines the PHY, MAC, LINK and CONVERGENCE protocol stack layers for the G.9954v2 system providing the following features: Operation over phoneline and/or over coax, PHY-layer payload transmission rates of 4 to 320 Mbit/s, Rate adaptive transceivers that optimize data rates and packet error rates for dynamically varying channel conditions on a per-packet basis, QAM modulation technique for communication over phone wire or coaxial cabling, Spectrum notching over phoneline for compatibility with amateur radio services, Synchronous MAC protocol controlled by a dynamically elected master employing a collision avoidance media access strategy, Support for constant and variable bit-rate data services, Peer-to-peer communication within a master-controlled network, Packet aggregation (packetization) performed within the G.9954v2 protocol stack layer up to latency limits of the service flow and available transmission bandwidth, Quality of service guarantees for bandwidth, jitter, latency and BER, QoS support for services with explicit traffic and rate specifications providing a link layer that is well suited for streaming audio and video, Protocol-specific convergence layers, Backward compatible with G.9951/G.9952 in mode A over phoneline using G.9951/G.9952 asynchronous MAC protocol, Coexistence and interoperability between G.9954v1 and G.9954v2 devices in a mixed network, Compatibility with other phoneline services such as POTS, V.90, ISDN and G.992.1, G.992.2, G.992.3, and G.992.4, Compatibility with other coaxial services such as VDSL, VDSL2 and cable-TV channels, Interoperability between phone and coax PHY layers using spectral modes A and B, thus allowing a mixed phoneline/coaxial network, Local and remote management of G.9954v2 devices, Provisions for future security extensions.