The duration is capped at 240 seconds (4 minutes).
After that, the download is aborted.
The speed is given in megabits per second as is usual with bandwidth. This graph is not very representative of the real connection speed because of the TCP slow start problem and the short download times.
Success rate: ?/? (?%)
A green segment means that the address was reachable, and a red segment means that the address was unreachable. A ping is performed approximately every 5 seconds. A solid red block means that there were general problems with the connection. A "stuttering" region means that only some hosts were unreachable. The ping service picks hosts from a list in order. You can move your mouse over the image to get an aproximate time of that segment. The latest ping is at the top left, it then goes down linewise until it gets to the oldest ping on the bottom right.