There are several methods for predicting the available maximal data transfer rate on dedicated telecommunication connections. This chapter presents some generally used techniques for prediction and some results of a Mamdani-type fuzzy reasoning system that is used in a telecommunication research aimed to create new predicting methods. At the end of the article the results of various methods are compared. All presented techniques are used for evaluation of the twisted-pair based local loops of the telecommunication access networks. © Springer International Publishing Switzerland 2014.