The MPEG-4 standard encodes a video stream in 3 different frames, I, P and B, where the P and B frames depend on the I frame. Loosing an I frame is especially bad. In this paper we exploit the Partial Reliability features of the SCTP transport protocol to selectively retransmit I frames in presence of congestion, obtaining a better quality of the decoded stream.

Pre-Congestion Notification (PCN) is a means for protecting the quality of service for inelastic traffic admitted to a Diffserv domain. The overall PCN architecture is described in RFC 5559. This memo is one of a series describing possible boundary-node behaviors for a PCN-domain. The behavior described here is that for a form of measurement-based load control using three PCN marking states: notmarked, threshold-marked, and excess-traffic-marked. This behavior is known informally as the Controlled Load (CL) PCN-boundary-node behavior.

Pre-Congestion Notification (PCN) is a means for protecting the quality of service for inelastic traffic admitted to a Diffserv domain. The overall PCN architecture is described in RFC 5559. This memo is one of a series describing possible boundary-node behaviors for a PCN-domain. The behavior described here is that for a form of measurement-based load control using two PCN marking states: notmarked and excess-traffic-marked. This behavior is known informally as the Single Marking (SM) PCN-boundary-node behavior.

Pre-congestion notification (PCN) provides feedback about load conditions in a network to its boundary nodes. The PCN working group of the IETF discusses the use of PCN to implement admission control (AC) and flow termination (FT) for prioritized realtime traffic in a DiffServ domain. Admission control (AC) is a well-known flow control function that blocks admission requests of new flows when they need to be carried over a link whose admitted PCN rate already exceeds an admissible rate. Flow termination (FT) is a new flow control function that terminates some already admitted flows when they are carried over a link whose admitted PCN rate exceeds a supportable rate. The latter condition can occur in spite of AC, e.g., when traffic is rerouted due to network failures. This survey gives an introduction to PCN and is a primer for this new technology. It presents and discusses the multitude of architectural design options in an early stage of the standardization process in a comprehensive and streamlined way before only a subset of them is standardized by the IETF. It brings PCN from the IETF to the research community and serves as historical record.

This document describes the Access Node Control Protocol (ANCP). ANCP operates between a Network Access Server (NAS) and an Access Node (e.g., a Digital Subscriber Line Access Multiplexer (DSLAM)) in a multi-service reference architecture in order to perform operations related to Quality of Service, service, and subscribers. Use cases for ANCP are documented in RFC 5851. As well as describing the base ANCP protocol, this document specifies capabilities for Digital Subscriber Line (DSL) topology discovery, line configuration, and remote line connectivity testing. The design of ANCP allows for protocol extensions in other documents if they are needed to support other use cases and other access technologies.