Gnutella's service announcement in March 2000 stirred worldwide interest by referring to P2P model. Basically, the P2P model needs not the broker "the centralized management server" that until now has figured so importantly in prevailing business models, and offers a new approach that enables peers such as end terminals to discover out and locate other suitable peers on their own without going through an intermediary server. It seems clear that the wealth of content made available by peer-to-peer systems like Gnutella and Freenet have spurred many authors into considering how meta-data might be used to support more effective search in a distributed environment. This paper has reviewed a number of these systems and attempted to identify some common themes. At this time the major division between the different approaches is the use of a hash-based routing scheme.

Systems comprised of multiple interacting mobile agents provide an alternate network computing paradigm that integrates remote data access, message exchange and migration; which up until now have largely been considered independently. On the surface distributed systems design could be helped by a complete specification of the different interaction patterns, however the number of possible designs in any large scale system undergoes a combinatorial explosion. As a consequence this paper focuses on basic one-to-one agent interactions, or paradigms, which can be used as building blocks; allowing larger system characteristics and performance to be understood in terms of their combination. This paper defines three basic agent paradigms and presents associated performance models. The paradigms are evaluated quantitatively in terms of network traffic, overall processing time and size of memory used, in the context of a distributed DB system developed using the Bee-gent Agent Framework. Comparison of the results and models illustrates the performance trade-off for each paradigm, which are not represented in the models, and some implementation issues of agent frameworks. The paper ends with a case study of how to select an appropriate paradigm.