A good way to build a loosely coupled system is as a decentralized system. That is, each computing node is by default independent of all the others. Each computing node contains the whole application and work s even if there is no communication whatsoever between nodes. The system is then extended so that each node can use information from other nodes when it is available. Two important parts of such a design are the split protocol a nd the merge protocol. Split defines what happens when a connected node no longer communicates with other nodes, and merge defines how two independent nodes become connected again. The merge protocol is based on data coherence and may need input from the highest level of the system (e.g., human users) to resolve
