We present a monitoring system for a dynamic network in which a set of domain nodes shares the responsibility for producing and storing monitoring information about a set of visitors. This information is stored persistently when the set of domain nodes grows and shrinks. Such a system can be used to store traffic or other logs for auditing or can be used as a subroutine for many applications to allow significant increases in functionality and reliability. The features of our system include authenticating visitors, monitoring their traffic through the domain, and storing this information in a persistent, efficient, and searchable manner. The storage process is O(log n)-competitive in the number of network messages with respect to an optimal offline algorithm; we show that this is as good as any online algorithm can achieve and significantly better than many commonly used strategies for distributed load balancing

Summary form only given. We present and analyze a distributed hash table-based supervised peer-to-peer system that allows an even distribution of and efficient lookup for objects (e.g. data or tasks) stored in the system. A supervised peer-to-peer system is a system that is formed by a supervisor but in which all other activities can be performed on a peer-to-peer basis without involving the supervisor. Our system has average constant degree and can distribute objects evenly among the peers up to a constant factor in expectation. The supervised peer-to-peer approach makes the system particularly useful for computational grids. As an example, we discuss the use of our structure for recursively defined algorithms such as dynamic programming and distributed tree searches, and practical problems such as Web crawling; our structure distributes tasks randomly and prevents repeated computations to optimize parallel efficiency.

The tremendous growth of public interest in peer-to-peer systems in recent years has initiated a lot of research work on how to design efficient and robust overlay networks for these systems. While a large collection of scalable peer-to-peer overlay networks has been proposed in recent years, many fundamental questions have remained open. Some of these are: