Congestion Notification Process for Real-Time Traffic

This document specifies the usage of Explicit Congestion Notification (ECN) markings for real-time inelastic flows such as voice, video conferencing, and multimedia streaming. We build on the principles of RFC 3168, "The Addition of Explicit Congestion Notification to IP", and apply them to real-time inelastic traffic in DiffServ networks. Defined in this document are, new ECN semantics that provide two levels of experienced congestion along the path for real- time inelastic flows, the required ECN marking behavior in network nodes, and state the required behavior of end-systems that support this function with an explanation of how the two ECN schemes can co- exist safely in the network.