Abstract: A method of designing a network circuit for a telecommunications network is disclosed. The method includes storing first model data in a database representing a first model of the telecommunications network. Second model data is received representing a second model of the telecommunications network. The second model data defines node groups, each representing a plurality of network nodes of the first network model, and interconnections between node groups, each representing connectivity between node groups in the first network model. The method involves searching the second model data to select a route from a start node group to an end node group, the route specifying a plurality of node groups connected by interconnections in the second network model; and searching the first model data to select a circuit from a node of the start node group to a node of the end node group.