1. A method for determining loop parameters describing a topology of a twisted pair loop, having two ends, for a digital subscriber line system, wherein the loop parameters being represented by a vector θ comprising the steps of: receiving a measurement of a Single Ended Line Test (SELT) parameter measured at one end of the two ends; receiving a measurement of a Double Ended Line Test (DELT) loop transfer function measured at the two loop ends; generating a first model for the SELT parameter based on the loop parameters represented by the vector θ; generating a second model for the DELT loop transfer function based on the loop parameters represented by the vector θ; and determining the loop parameters represented by the vector θ by minimizing the difference between the first model and the measurement of the SELT parameter and by minimizing the difference between the second model and the measurement of the DELT loop transfer function, wherein the determined loop parameters are represented by the vector θ that provides the minimizations.