Redundancy, expanded switching capacity and fault isolation arrangements for use with an expandable telecommunications system. An inter-nodal network connects a plurality of programmable switching nodes or other nodes. One or more additional inter-nodal networks may be provided across some or all of the ones. The bandwidth provided by the additional network(s) may be used to provide redundancy against failure of the primary network or the nodes, increased switching capacity or a combination of both. In addition, faults which occur either within a particular node or within an inter-nodal network may be effectively isolated and prevented from degrading system performance.