This survey presents a framework for analyzing peer-to-peer (P2P) content distribution technologies. It focuses on non-functional characteristics such as security, scalability, performance, fairness, and resource management, and examines how these are reflected in and affected by architectural design decisions in current P2P systems. The survey discusses current P2P systems and infrastructure technologies in terms of distributed object location and routing mechanisms, content replication, caching, migration, encryption, access control, authentication, anonymity, deniability, accountability, reputation, and resource trading and management schemes. The survey defines P2P computing as a class of applications that take advantage of resources available at the edges of the internet, such as storage, cycles, content, and human presence. It notes that there is no general agreement on what constitutes P2P, as systems may be labeled P2P based on external perception rather than internal operation. The two defining characteristics of P2P architectures are the sharing of computer resources by direct exchange, and the ability to treat instability and variable connectivity as the norm. The survey also discusses the relationship between P2P and Grid computing, noting that P2P addresses failure, while Grid computing addresses infrastructure. It classifies P2P applications into three categories: communication and collaboration, distributed computation, and content distribution. The focus of the survey is content distribution, a significant area of P2P systems that has received considerable research attention. The survey presents an analysis framework for P2P content distribution systems, identifying key non-functional characteristics such as security, privacy, availability, scalability, performance, fairness, and resource management. It examines how these characteristics are affected by design features and solutions adopted by current P2P systems. The survey also discusses various P2P architectures, including unstructured and structured systems, and their characteristics, advantages, and shortcomings. It highlights the importance of scalability, fault tolerance, and self-organization in P2P systems, and the need for adaptive network topologies to maintain connectivity and performance. The survey concludes that P2P content distribution systems are well-suited for applications where keyword searching is common, content is typically replicated at a fair fraction of participating sites, the node population is highly transient, and users accept a best-effort content retrieval approach.This survey presents a framework for analyzing peer-to-peer (P2P) content distribution technologies. It focuses on non-functional characteristics such as security, scalability, performance, fairness, and resource management, and examines how these are reflected in and affected by architectural design decisions in current P2P systems. The survey discusses current P2P systems and infrastructure technologies in terms of distributed object location and routing mechanisms, content replication, caching, migration, encryption, access control, authentication, anonymity, deniability, accountability, reputation, and resource trading and management schemes. The survey defines P2P computing as a class of applications that take advantage of resources available at the edges of the internet, such as storage, cycles, content, and human presence. It notes that there is no general agreement on what constitutes P2P, as systems may be labeled P2P based on external perception rather than internal operation. The two defining characteristics of P2P architectures are the sharing of computer resources by direct exchange, and the ability to treat instability and variable connectivity as the norm. The survey also discusses the relationship between P2P and Grid computing, noting that P2P addresses failure, while Grid computing addresses infrastructure. It classifies P2P applications into three categories: communication and collaboration, distributed computation, and content distribution. The focus of the survey is content distribution, a significant area of P2P systems that has received considerable research attention. The survey presents an analysis framework for P2P content distribution systems, identifying key non-functional characteristics such as security, privacy, availability, scalability, performance, fairness, and resource management. It examines how these characteristics are affected by design features and solutions adopted by current P2P systems. The survey also discusses various P2P architectures, including unstructured and structured systems, and their characteristics, advantages, and shortcomings. It highlights the importance of scalability, fault tolerance, and self-organization in P2P systems, and the need for adaptive network topologies to maintain connectivity and performance. The survey concludes that P2P content distribution systems are well-suited for applications where keyword searching is common, content is typically replicated at a fair fraction of participating sites, the node population is highly transient, and users accept a best-effort content retrieval approach.