A complex question with many different options at many different price points. If you want to get the most insightful data, you'll want switches and routers that are NetFlow enabled, and something like NetCrunch 8 that can read and display the collected data.
Network monitor.
yellow network monitor
Ntop is a network monitoring tool that provides detailed information on network traffic. To use it, you typically install it on a server and access its web interface using a browser. From there, you can view real-time network traffic, monitor bandwidth usage, and analyze network protocols and traffic patterns.
A sniffer is typically a software tool that can be installed on a device, such as a computer or smartphone, to capture and analyze network data packets. It is not a physical device itself but rather a program used to monitor network traffic.
A bandwidth monitoring tool shows how much bandwidth your network is using. This tool can also analyze historic trends in website and network traffic.
The tool used to regulate the traffic that traverses into or out of a network is known as a firewall. It serves as a security barrier, scrutinizing the network traffic based on predefined rules, and blocks or permits data packets accordingly. It's an essential component in maintaining the security and integrity of a network.
Winshark is the networking tool to check the network traffic over the internet.
Detect network bottlenecks.
The Monit tool is used to monitor servers and slave computers on a corporate network. The information that they gather is used to help the performance of the computers and network.
A firewall is the tool that blocks ports, programs, or any other network traffic from incoming or outgoing connections.
Protocol Analyzer
Network Monitoring Tools calculates the bandwidth utilization, and scans the traffic for errors through SNMP. The tool also provides asset details such as the OS, installed software, and hardware and informs you about the general availability and performance of the network elements. Discover how easy it is to detect, diagnose, and resolve network problems with Orion Network Performance Monitor (NPM). Orion NPM is the easiest product of its kind to use and maintain, meaning you will spend more time actually managing networks, not supporting Orion NPM. Another useful tool is 10-Strike Network Monitor. It helps to monitor all the hosts on the network and detect failures in time.