A Peer-to-Peer Approach to Enhance Middleware Connectivity

One of the problems of middleware for shared state is that they are designed, explicitly or implicitly, for symmetric networks. However, since the Internet is not symmetric, end-to-end process connectivity cannot be guaranteed. Our solution to this is to provide the middleware with a network abstraction layer that masks the asymmetry of the network and provides the illusion of a symmetric network. We describe the communication service of our middleware, the Distribution Subsystem (DSS), which carefully separates connections to remote processes from the protocols that communicate over them. This separation is used to plug-in a peer-to-peer module to provide symmetric and persistent connectivity. The P2P module can provide both up-to-date addresses for mobile processes as well as route discovery to overcome asymmetric links.