1. Technical Field of the Invention
The present invention relates to providing high-speed communications services to ordinary residences and small businesses on digital subscriber lines.
2. Background of the Invention
The sudden emergence of the Internet has produced an urgent demand for high-speed communications services to ordinary residences and small businesses. These services are distinguished by bursty data patterns and asymmetrical data transfer—far more information sent toward the subscriber premises than received from it. A partial response to this need, at least on the physical signal level, has been found in new “xDSL” transmission technologies, such as ADSL (Asymmetric Digital Subscriber Line). These have recently become sophisticated enough to allow dynamic bit-rate adaptation on each subscriber line, so that a wide range of loop lengths can be accommodated. But all this variability (bursty data, dynamic bit rates, etc.) has made it nearly impossible to predict, control, manage, or guarantee the Quality of Service (QoS) provided to each subscriber, as required for a viable commercial service.
Several companies are working on ADSL products using DMT (Discrete Multi-Tone) and/or CAP (Carrier-less Amplitude Phase Modulation) technology—each with their own equipment configurations and target applications. These products simply multiplex the ADSL data streams together with little or no flexible bandwidth control and no QoS management features.