Published in eBook and USB produced by Sigma Orionis, 2012
Managed Internet provides guaranteed Quality of Service to IP-based multimedia applications. Yet managed flows require support from the underlying infrastructure and rely on individual Service Level Agreements with the corresponding Service Provider. Therefore, QoS guarantees are missing for flows that are delivered beyond the service provider’s infrastructure as well as over lossy home network segments. Outside of managed infrastructure, reliability and multiple access are ensured by selfmanaged end-to-end error and congestion control on transport layer. However, available transport layer protocols optimize their objectives in error and congestion control without respect to the application’s individual QoS constraints such that multimedia services suffer from significant degradation. In this paper, we present a novel protocol layer that efficiently supports the reliability required by multimedia services under their individual delay constraint. Specifically, the protocol is designed to provide suchlike applications a self-managed, predictably reliable end-toend channel on arbitrary Internet paths. The solution is based on the Predictably Reliable Real-time Transport (PRRT) protocol that efficiently optimizes proactive and reactive error control under strict time constraints. We evaluate PRRT’s QoS provisioning on unmanaged Internet paths under the influences of congestion loss and compare the results with standardized QoS requirements as defined by the ITU-T Y. 1541 QoS classes.