1. A method for evaluating performance values supported by access links in a packet network that interconnects regions of an enterprise network, said method comprising: obtaining a plurality of test measurements for a set of N access links; formulating a matrix equation (Ax=D), where A is an invertible matrix, x is a vector of unknown access link performance parameters and D is a vector based on said plurality of test measurements; assigning one or more numeric values to one or more unproducible equations in said matrix equation based on one or more system properties; and obtaining a performance parameter value on each directed edge for the set by applying an inverse matrix A −1 to each side of Ax=D.