You can see the network activity via the activity monitor:
View network activity in the Activity Monitor window
- In the Activity Monitor app
on your Mac, click Network (or use the Touch Bar) to see the following at the bottom of the window:- Packets in, Packets out: The total number of packets received and sent.
- Packets in/sec, Packets out/sec: The speed of information being transferred (in packets per second). This number can be displayed in the graph.
- Data received, Data sent: The total amount of information moved (in megabytes).
- Data received/sec, Data sent/sec: The amount of information moved over time (in bytes per second), also called throughput. This number can be displayed in the graph.
- To display more columns, choose View > Columns, then choose the columns you want to show.
See this link for further reference
View network activity in Activity Monitor on Mac – Apple Support (UK)