MODELLING APPARATUS AND METHOD

A method determined a routing of data between two network elements of a telecommunications network, which are interconnected via a transmission path. The method includes identifying plurality of layers of a telecommunications model from which the transmission path is comprised, and developing a reachability table by identifying a connection between each transmission element in each layer to other transmission elements in the same or a different layer of the transmission path. For each connection defining a set of communications parameters which define a cost of communicating data via the connection and allocating a weighting value for communicating data via the connection, for all possible routes between the two network elements along the transmission path via each of the layers modeling the effect of the connection for routing the data in accordance with the set of communications parameters for the connection and determining a weighted result along each path, and combining the weighted results to determine a metric of performance for each of the possible routes. An optimum route can then be determined for routing data in accordance with for example a minimum cost metric.