A method for controlling optimization of vectoring performance, using precoding in the transmission of data between at least two transmitters and a plurality of receivers via a plurality of communication channels over a plurality of subcarrier frequencies, the method comprising determining communication performance for said communication channels collectively, by using default precoding parameters; comparing between said communication performance and corresponding service level agreement data associated with each of said communication channels, thereby generating management control data; determining updated precoding parameters, according to said management control data; and applying said updated precoding parameters.