ITU-T G.9954

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.