In System > Secure backbone > Interface list, the graphs don’t display and N/A is shown instead when there’s too little data over the time period to show a graph. Although the reasoning behind this behaviour is understandable, it’s not possible to distinguish between a lack of data caused by a pipeline problem and a lack of traffic. It would be better to show a 0 bps or 0 pps when there’s no traffic, and N/A when the data couldn’t be retrieved.