The quality of audio and video delivered over the IPCablecom architecture will depend on multiple factors: the end device performance, the network's inherent quality, and the intelligence of the system resource allocation policy. This document defines mandated codecs and capabilities supporting audio and video applications, with a particular emphasis on the stringent requirements of IP-based voice communications.
Acceptable voice communications functionality imposes strict latency and packet-loss criteria on IP implementations and will thus stress system resources, particularly if bandwidth becomes congested or saturated. Video applications — while more forgiving to dropped packets and latency — require bandwidth of at least an order of magnitude more than audio applications. The IPCablecom architecture is designed to support both types of applications simultaneously.
Speech and video compression are evolving technologies. New algorithms are being enabled as more sophisticated and higher performing processors become available at lower cost. Additionally, the system infrastructure and mechanisms for allocating resources will evolve. Due to this dynamism, the priority in designing the architecture is to define a robust system to accommodate evolving technology without creating a legacy burden.
Therefore, the IPCablecom philosophy is to establish cost-effective envelopes for network and device performance to enable the most appropriate current technology, while allowing upgrades as technology and market needs evolve. To address near-term market needs, this document also specifies codec and performance mandates to deliver the quality-of-service necessary for launching competitive services.