The graphics shown here inform you about the inbound/outbound network traffic on your interfaces.
The first page shows the traffic for all interfaces during the last hour (by default). The units used will be adjusted according to the traffic on each interface, so you can have the traffic expressed in bytes/sec., kbytes/sec., mbytes/sec., etc.
At the top of the page is a list of the available time scales for the graphics: Hourly, Daily, Weekly, Monthly and Yearly. To change the time scale, just click on the corresponding link.
Each graphic also tells you the average and maximum inbound/outbound traffic for the network interfaces. Inbound traffic is represented in green and outbound traffic in dark gray.
Clicking on at the right of each graphic
(available only in Hourly Graph mode) will take you to traffic
statistics on the corresponding interface.
Clicking on the Refresh button will update the graphics.