Workshop Report for the 3rd International Workshop on Peer-to-Peer Systems (IPTPS 2004) -- Workshop Report for the 3rd International Workshop on Peer-to-Peer Systems (IPTPS 2004) -- I Miscellaneous -- A Practical Distributed Mutual Exclusion Protocol in Dynamic Peer-to-Peer Systems -- On the Cost of Participating in a Peer-to-Peer Network -- 2 P2P or Not 2 P2P? -- II Networking -- On Transport Layer Support for Peer-to-Peer Networks -- Supporting Heterogeneity and Congestion Control in Peer-to-Peer Multicast Streaming -- Rapid Mobility via Type Indirection -- P6P: A Peer-to-Peer Approach to Internet Infrastructure -- III Routing -- Comparing the Performance of Distributed Hash Tables Under Churn -- DHT Routing Using Social Links -- When Multi-hop Peer-to-Peer Lookup Matters -- IV Load Balancing and Searching -- Uncoordinated Load Balancing and Congestion Games in P2P Systems -- Simple Efficient Load Balancing Algorithms for Peer-to-Peer Systems -- The Case for a Hybrid P2P Search Infrastructure -- Making Peer-to-Peer Keyword Searching Feasible Using Multi-level Partitioning -- V Miscellaneous -- Providing Administrative Control and Autonomy in Structured Peer-to-Peer Overlays -- Willow: DHT, Aggregation, and Publish/Subscribe in One Protocol -- Friends Troubleshooting Network: Towards Privacy-Preserving, Automatic Troubleshooting -- Spurring Adoption of DHTs with OpenHash, a Public DHT Service -- VI Applications -- UsenetDHT: A Low Overhead Usenet Server -- Clustering in Peer-to-Peer File Sharing Workloads -- Cluster Computing on the Fly: P2P Scheduling of Idle Cycles in the Internet -- VII Security -- Robust Distributed Name Service -- Peer-to-Peer Authentication with a Distributed Single Sign-On Service -- Secure Acknowledgment of Multicast Messages in Open Peer-to-Peer Networks -- VIII Routing -- Know Thy Neighbor’s Neighbor: Better Routing for Skip-Graphs and Small Worlds -- SmartBoa: Constructing p2p Overlay Network in the Heterogeneous Internet Using Irregular Routing Tables -- Diminished Chord: A Protocol for Heterogeneous Subgroup Formation in Peer-to-Peer Networks.On February 26–27, 2004, the 3rd International Workshop on Peer-to-Peer S- tems (IPTPS 2004) brought researchers and practitioners together to discuss the latest developments in peer-to-peer technologies, applications, and systems. As the third workshop in the series, IPTPS 2004 continued the success of the previous workshops in pioneering the state of the art in peer-to-peer systems and identifying key research challenges in the area. The workshop received 145 submissions in the form of ?ve-page position papers. As with previous workshops, submissions went through two rounds of reviews by an international program committee of 14 experts from industry and academia.In the ?rst round eachsubmission receivedtwo reviews.In the second round we focused our attention on submissions with either positive reviews, or with reviews that expressed substantially di?erent opinions. In addition to the technical merit, the reviewing process emphasized originality and the potential of the submission to lead to interesting discussions during the workshop. Intheend,theprogramcommitteeselectedaworkshopprogramof27papers coveringawiderangeoftopicsincludingnewpeer-to-peerapplications,advances in routing, load balancing, searching, as well as transport, mobility, and other networking topics. Authors revised accepted position papers to six pages for the workshop program, and made a ?nal round of revision for this volume. The workshop was composed of eight sessions that spanned two days. To focus discussions, attendance was limited to 67 participants and included s- stantialtimeforinteractionanddiscussionbetweensessionsandatsocialevents.