The present paper proposes architecture for quality-adaptive real-time transmission of audio streams over the Internet. A feedback mechanism between the transport layer and the application layer, that ensures the quality adjustment of real-time streams, forms the backbone of this architecture. A rate adaptation protocol, based on the additive increase/multiplicative decrease principle, is the underlying protocol for the transport layer. It has been proved to be TCP-friendly, fair and effective in keeping the network congestion control separate from the application layer. A quality-adaptive layered coder serves to achieve reliability in the application layer.