for MAC users There are a lot of network usage monitor, in order to improve the speed of the Internet, many users want to use this type of tool to see where the speed is used, or to limit the network of "big Net". But Mac's new users, do you know that the activity monitor in the system already provides similar functionality?
After you open the active monitor in your MAC system, note that there are 5 tabs at the top, CPU, memory, energy, disk, and network. Select the last "network" where you can see each process on your computer and the size of the data currently sent and received by each process. If you select a process and press the "X" in the upper-left corner, you can exit the process. It is to be noted that some processes may be restarted automatically.
Now you know what processes are using your data (traffic), and if it's an application that takes up data traffic, consider whether its settings provide the option to disable the network. If the process is not an application, you can search for the name of the process on the network. For example, there is a process called "Nsurlsessiond", which consumes a lot of data traffic, after searching the process name you can find that the process and the Apple server is connected, so by turning off the ICloud photo gallery can solve (excessive traffic) problem.