How to Monitor Network Activityby Stephen Lilley
If your computer is connected to a local area network or some type of Internet network (either a wired or wireless), you can monitor any activity that is going on over the network using Windows' advanced "Network and Sharing Center" feature. This feature will allow you to monitor all network activity from any computer on the network and see things like connection speeds, number of users and more.
Click "Control Panel."
Click "Network and Sharing Center."
Click on "See Full Map" to see a listing of all computers and devices that are connected to the same network. You will also see information relating to the network itself, like whether or not your network is just a local area network (meaning it is only made up of computers connected to other computers) or an Internet network (meaning it is made up of computers connected to the Internet).
Click on the name of your network under the "Connections" portion of the main "Network and Sharing Center" window. You will be able to see a list of the properties of your network, including how many packets of information (measured in kilobytes) are being transmitted over the network at any given time. You will also be able to see how much information has been transmitted over the network for the duration that it has been operational, as well as the amount of time it has been operational.