To view the network usage:

• Click Finder > Applications > Utilities > Activity Monitor. The Activity Monitor allows you to view the system CPU usage in real time.
• Click the Network tab to view the network stats.

You can use the Network tab to monitor the amount of network traffic that’s occurring on your system. The Network tab also shows the number of packets in and packets out, the rate of packets in seconds, and the amount of data moved in megabytes. It also shows the throughput of data over time using a small graph.