PPDN, Push-Pull Distribution Network, — a proposal for a novel framework for peer-to-peer collaborative research network is presented. Some requirements not addressed by the currently proposed systems are discussed, and we show how these issues are addressed in our framework. The framework is based on a distributed approach and the concept of semantic web. The collaborative network is represented as a graph, with push and pull edges. The nodes can act as autonomous or semi-autonomous agents, implementing different policies.