What is line speed?
Line speed refers to how many bits per second your Internet connection can download. This is usually how your Internet Service Provider (ISP) represents your connection speed when you sign up with them. For home Internet connections, the speed is measured in kbps (kilobits per second) or mbps (megabits per second).
For example, a 25/5 NBN plan can theoretically download at 25 mbps and upload at 5 mbps.