Updates interested RT list.

        Check if interested RTs have changes from previous check.
        Takes appropriate action for new interesting RTs and removal of un-
        interesting RTs.

def update_interested_rts(self):
        """Updates interested RT list.

        Check if interested RTs have changes from previous check.
        Takes appropriate action for new interesting RTs and removal of un-
        interesting RTs.
        """
        prev_global_rts = self._global_interested_rts
        curr_global_rts = self._compute_global_interested_rts()

        new_global_rts = curr_global_rts - prev_global_rts
        removed_global_rts = prev_global_rts - curr_global_rts

        # Update current interested RTs for next iteration
        self._global_interested_rts = curr_global_rts

        LOG.debug('Global Interested RT changed, new RTs %s, removed RTs %s',
                  new_global_rts, removed_global_rts)
        tm = self._core_service.table_manager
        tm.on_interesting_rts_change(new_global_rts, removed_global_rts)