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.