module may be different by constantly monitoring the input and the output of the module through the compound signal the gain attenuation given to a specific channel or channel group can easily be calculated by the controller as noted above the system illustrated in fig3 can contain other network elements fig7 illustrates such an expanded system fig7 differs from fig3 in that fig7 incorporates an optical cross connect module 310 and an optical add drop multiplexer oadm 320 as can be seen the outputs of these two modules 310 320 are fed into compensation modules 110 a 110 b and 110 c the controller 120 knowing that the compensation modules 110 a 110 b 110 c are receiving channels from modules which reduce signal strength can thus command these compensation modules to amplify their respective channels alternatively if the input from these network elements are not desired the controller can command the compensation modules receiving their channels to attenuate and suppress to a certain degree these channels to further explain if the channel entering the system from the oadm 320 is not desired then the compensation module 110 a can be commanded by the controller 120 to attenuate this channel on the other hand the output of the cross connect 310 can simultaneously.