It is essential for companies that have large data networks to monitor network traffic and usage for more efficient troubleshooting when there are outages in the system, and to determine whether or not an upgrade in the system is already necessary. It is possible to monitor traffic within the Local Area Network (LAN), the Wide Area Network (WAN), and certain points in the Internet. In monitoring network flow, the following general information is important to see which area of the network is active and which area uses most of the bandwidth: the local IP address, remote IP address, source port, destination port, IP protocol, and logged in user name.
There are several software programs that can measure and monitor network traffic and usage. There are also free Internet traffic monitor software programs, which are ideal for home use. For use in companies, a dedicated computer is used for monitoring network traffic and usage. Monitoring software is installed in this computer, and it captures information on network traffic in real time. This computer is connected to a network monitor router. This information is stored and one can check what happened to the network at a certain time of the day.
The first step in monitoring network traffic and usage is to have a layout of the existing computer network on paper, showing all the local network connections, servers, and routers. Then determine how often each user needs to use the network (i.e., network printing, use of Internet or intranet, instant messaging, use of email). This way, it is already expected that certain users will cause heavy network traffic. The lay out should include each user’s IP address so when the monitoring software is used, network users are identified through their respective IP addresses.
Once the users are all defined, the network administrator can run the monitoring software and come up with real time traffic graphs to see the activities of each point in the network. It can serve as a LAN monitor to observe local network activity. The software can also serve as an Internet traffic monitor to see the amount of Internet usage in real time. It has the capability of seeing which websites a certain user has been visiting. This way, the administrator can see whether the bandwidth is maximized or is used unnecessarily. Once these websites are defined, the administrator can block it to avoid future access.
The monitoring software can also be set to alarm the network administrator for excessive usage or unauthorized activities within the network.
Network monitoring software has a reporting interface that can be customized depending on the type of information needed. Reports can include tables, graphs and charts, and also maps to show which part of the network has the most traffic. It also allows for WAN monitoring to determine network activity at the wide area network level beyond the local network.
Along with monitoring software, a network monitoring interface card (NMIC) can be installed in the dedicated computer. Aside from network monitoring, it can also be used to detect network intrusion (hacking), flow analysis and traffic filtering.