Synapse: A Scalable Protocol for Interconnecting Heterogeneous Overlay Networks

This paper presents Synapse, a scalable protocol for information retrieval over the inter-connection of heterogeneous overlay networks. Applications on top of Synapse see those intraoverlay networks as a unique inter-overlay network. Scalability in Synapse is achieved via co-located nodes, i.e. nodes that are part of multiple overlay networks at the same time. Co-located nodes, playing the role of neural synapses and connected to several overlay networks, give a much wider search area and provide alternative routing. Built-in primitives to deal with social networking give an incentive for cooperation between nodes. Results from simulation and experiments show that Synapse is scalable, with a communication and state cost scaling with the same complexity of the connected networks. Because of alternative routing, Synapse gives also a practical solution to network partitions. We precisely capture the behavior of key metrics measuring Synapse and present results from simulations as well as some live run experiments of a client prototype on the Grid’5000 platform. The client implements the Synapse protocol in the precise case of the inter-connection of many Chord overlay networks.