Monitoring a network typically involves observing resource usage on a server and measuring network traffic. You can use Network Monitor to understand the traffic and behaviour of your network components. Unlike System Monitor, which you use to monitor hardware and software, Network Monitor exclusively monitors network activity.

To check resource usage, start by tracking the counters on your server. To focus on network resource usage, monitor the counters that correspond to the various layers of your network configuration. Abnormal network counter values often indicate problems with a server's memory, processor, or hard disks. For this reason, the best approach to monitor a server is to watch network counters with the following performance counters:

• Processor\ %
• Processor Time,
• PhysicalDisk\ % Disk Time, and
• Memory\ Pages/sec.

Most network resources, including network adapters and protocol software, use non-paged memory. A computer can page excessively if most of its physical memory is allocated to network activities, which leaves a small amount of memory for processes that use paged memory.
To verify this usage, check the computer's system event log for entries indicating it is out of paged or non-paged memory.

You can use Network Monitor to observe throughput across network layers. Investigating network performance includes monitoring activity at different network layers. There are four layers in which you monitor network activity:

• the data-link layer,
• the network layer,
• the transport layer, and
• the presentation or program layer.