The authors propose a fault-tolerant binary tree architecture with the advantages of high system reliability and limited configuration time. The system is made up of several groups, each group containing M fault tolerant modules, and each module consisting of three active nodes and one spare node to construct a bi-level active subtree. In each group, an idle local spare node in a module can be transmitted to the other module with two faulty nodes. Thus, a module with one spare node is capable of tolerating two faulty nodes. Typically, a group will survive if no module has more than two faulty nodes and the number of modules with two faulty nodes is less than M/2. This allows for space-sharing among the modules in a group. Consequently, the module, the group, and the system reliability are increased. The system uses a modular reconfiguration which takes only a limited time despite the network size. An example and an analysis of the proposed system reliability are given.