This volume presents the proceedings of the 6th International ICST Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness and of the Third International ICST Workshop on Advanced Architectures and Algorithms for Internet DElivery and Applications. Both events were held in Las Palmas de Gran Canaria in November 2009. To each of these events is devoted a specific part of the volume. The first part is dedicated to the proceedings of ICST QShine 2009. The first four chapters deal with new issues concerning the quality of service in IP-based telephony and...