triple speed ethernet - ff_tx_rdy signal toggling

hi,

am using tripple speed ethernet in my project, in that FF_tx_rdy signal is toggling, but from the user guide i saw it is depending on ff_tx_a_full, but this signal is also coming proper(ie low) always then also ff_tx_rdy is toggling. all other signals such as link,error signal are properly coming

how to overcome this problem, is that ff_tx_rdy is depend on other signal...