Network traffic controller with PRTG

Three things: it should be easy to use, customizable – that is, you should be able to configure it so it's tailored to your organization's specific needs – and scalable. Bonus points if it can also test bandwidth without crashing your network.

And, not because we're biased, but Paessler PRTG can do all four. With many preconfigured sensors (and the ability to create your own), support for all major protocols – including SNMP, WMI, Windows performance counters, NetFlow, sFlow, IPFIX, and jFlow, SSH, HTTP and HTTPS, FTP, ping, and more – and the ability to monitor unlimited local and remote devices, PRTG can handle both basic and complex, distributed networks with ease. Better still, you can tailor it exactly the way you want it, from the way your monitoring environment looks to individual parameters and alert thresholds. But don't take our word for it. Try it free for 30 days and see for yourself.

PRTG's sensors monitor specific hardware and software parameters that could impact traffic, such as bandwidth, latency, jitter, and quality of service. Once you pick your preferred parameters – these could be specific incidents, such as a congested port, or a threshold value you don't want to cross – PRTG monitors it round the clock and alerts you if there are issues, so you can troubleshoot what's causing it.

SNMP, packet sniffing, and flow protocols are all tools used in network monitoring and traffic analysis, but they serve different purposes and operate in distinct ways. Here's a breakdown:

SNMP

SNMP operates by querying devices to retrieve specific data like CPU load, memory usage, network interfaces status, and traffic statistics. SNMP agents installed on devices respond to these queries from an SNMP manager.

SNMP provides high-level, structured data, but it does not capture individual packets or detailed traffic flows. It is useful for network administrators who want to track performance metrics, detect faults, or configure network devices. For example, it can alert an admin when a router's CPU reaches a critical usage level.

Packet sniffing

Packet sniffing is used to capture and analyze individual packets traveling across a network. A packet sniffer intercepts all network traffic, or traffic to/from a specific device, and captures the individual packets for analysis.

Packet sniffing is very detailed, capturing every bit and byte of data on the network. This includes everything from packet headers to actual payloads (which might be encrypted). It is ideal for debugging network issues, troubleshooting, or detecting security incidents. For instance, packet sniffers can help diagnose slow network performance by showing which applications or hosts are consuming the most bandwidth.

Flow protocols (NetFlow, jFlow, sFlow, IPFIX)

Flow protocols are used for network traffic flow monitoring and analysis, providing insights into who is communicating with whom, how much data is being transferred, and which protocols are in use. NetFlow (Cisco), sFlow (sampled Flow), jFlow (Juniper), and IPFIX (IETF) all collect summarized metadata about network traffic, rather than capturing full packets. Flow data includes information like source/destination IPs, ports, protocol types, packet counts, and timestamps.

Flow protocols provide summarized information about traffic patterns, rather than full packet details. Flow is less granular than packet sniffing but more focused on traffic behavior than SNMP. Flow protocols are excellent for long-term traffic analysis, capacity planning, and detecting network anomalies like DDoS attacks or unusual traffic patterns. For example, NetFlow can reveal if a particular IP is sending a massive amount of data to multiple destinations (indicating a possible security breach).

In PRTG, “sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, for example the traffic of a switch port, the CPU load of a server, or the free space on a disk drive.

On average, you need about 5-10 sensors per device or one sensor per switch port.