BER measurment with SDH/gigabit ethernet/fibre channel protocol

hi,

I have to perform a BER measurement of a component that use various protocol as SDH, gigabit ethernet, fibre channel.
I already read the standards papers of the different protocols but no one gave me a solution to do the measurement.
For example i don't know the required length of the pseudo random binary sequence. 2^31-1 , 2^15-1, etc...according to the bit rate or the frame structure. 😕