This Festschrift volume is published in honor of Gunter Haring on the occasion of his emerital celebration and contains invited papers by key researchers in the field of performance evaluation presented at the workshop Performance Evaluation of Computer and Communication Systems - Milestones and Future Challenges, PERFORM 2010, held in Vienna, Austria, in October 2010. Gunter Haring has dedicated most of his scientific professional life to performance evaluation and the design of distributed systems, contributing in particular to the field of workload characterization. In addition to his own contributions and leadership in international research projects, he is and has been an excellent mentor of young researchers demonstrated by their own brilliant scientific careers. The 20 thoroughly refereed papers range from visionary to in-depth research papers and are organized in the following topical sections: milestones and evolutions; trends: green ICT and virtual machines; modeling; mobility and mobile networks; communication and computer networks; and load balancing, analysis, and management.

This book constitutes the refereed proceedings of the 4th International Workshop on Self-Organizing Systems, IWSOS 2009, held in Zurich, Switzerland, in December 2009.

The 14 revised full papers and 13 revised short papers presented were carefully selected from the 34 full and 27 short paper submissions. The papers are organized in topical sections on ad hoc and sensor networks; services, storage, and internet routing; peer-to-peer systems; theory and general approaches; overlay networks; peer-to-peer systems and internet routing; wireless networks; and network topics.

We welcome you to the proceedings of the Third International Workshop on Self-Organizing Systems (IWSOS 2008) hosted at the University of Vienna, Austria.IWSOSprovidesanannualforumtopresentanddiscussrecentresearch inself-organizationfocusedonnetworksandnetworkedsystems.Researchinse- organizingnetworkedsystemshasadvancedinrecentyears, buttheinvestigation of its potentials and limits still leaves challenging and appealing open research issues for this and subsequent IWSOS workshops. Complexandheterogeneousnetworksmakeself-organizationhighlydesirable. Bene?ts envisioned by self-organization are the inherent robustness and ada- ability to new dynamic tra?c, topology changes, and scaling of networks. In - dition to an increasingly complex Global Internet, a number of domain-speci?c subnetworks bene't from advances in self-organization, including wireless mesh networks, wireless sensor networks, and mobile ad-hoc networks, e.g., vehi- lar ad-hoc networks. Self-organization in networked systems is often inspired by other domains, such as nature (evolution theory, swarm intelligence), sociology (human cooperation), and economics (game theory). Aspects of controllability, engineering, testing, andmonitoringofself-organizingnetworksremainchalle- ing and are of particular interest to IWSOS. This year, we received 70 full paper and 24 short paper submissions from authors of 33 di?erent countries. This strong interest in the workshop is very encouraging for research in self-organizing systems and allowed us to provide a strong technical program. Based on the recommendations of the Technical Program Committee and external expert reviewers, we accepted 20 full papers from the full paper submissions and invited 9 as short papers. Of the 24 short paper submissions we accepted 4 for presentation for a total of 13 short pape