Peer-to-peer (P2P) architecture needs new middleware technologies and counterparts to the widely established CORBA, EJB, COM+, and messaging systems products. Specially designed middleware would release the advantages of peer-to-peer networks to a broad spectrum of applications. Network-specific advantages like scalability, fault tolerance, and resource availability could easily be utilized without any concerns about their underlying infrastructure and resources. The authors address this need with P2P messaging system, which focuses on high-performance group communication based on a publish/subscribe model. The P2P messaging system considers the heterogeneous and dynamic character of peer-to-peer networks by an augmented topology and its supporting features.