US Patent 7680067 Peer-to-peer data synchronization architecture

To enable the peer-to-peer synchronization among multiple devices, each device in the peer network keeps track of the changes it makes to any shared data and also keeps track of its own knowledge of the changes made by other devices. When two or more peer devices communicate, they share with each other their information about any changes made to the shared data by them or by other devices. This allows the devices to synchronize with each other to the extent that each of the devices knows what changes have been made by it or by other devices in the peer network.