Real Network Monitoring with UDP

In the world of industrial automation, “it must be the network” is often a last-resort conclusion—but one that’s surprisingly common. When OPC communications drop, lag, or misbehave for no apparent reason, it’s easy to suspect software, hardware, or configuration settings. Yet the actual culprit is frequently lurking deep within the infrastructure: a network issue hidden by automated recovery mechanisms, such as TCP retransmission.

This is where OPC Expert’s Network Monitoring stands apart.

Rather than smoothing over the cracks with TCP, OPC Expert leverages UDP communication to shine a light directly on the network’s raw performance—warts and all.

Most conventional network tools rely on TCP for a reason: it’s designed to be “reliable.” It detects lost packets, reorders them if necessary, and retransmits anything that goes missing. This makes it great for file transfers, websites, and general internet use.

But in automation and industrial networking, that reliability is a double-edged sword.

TCP masks real-world issues. Packet loss? Covered up. Latency spikes? Smoothed over. It tells you everything is fine—until it isn’t.

Unlike TCP, UDP doesn’t pretend. It doesn’t retransmit lost data or hide delivery delays. It simply sends packets and lets the chips fall where they may.

And that’s precisely why OPC Expert uses UDP in its Network Monitoring tool.

By sending raw UDP traffic between client and server, OPC Expert can accurately:

• Detect packet loss in real-time
• Reveal out-of-order delivery
• Measure actual throughput without protocol compensation
• Simulate communication under load conditions

Take a look at this Screenshot from an OPC Expert test using UDP:

Here, over 298,000 messages were lost—a whopping 6.65% of all messages sent. A traditional TCP-based test might have hidden these drops entirely through automatic recovery.

OPC Expert’s UDP-based testing doesn’t just throw packets into the void. It gives users the ability to:

• Throttle throughput to simulate increasing traffic loads (network-monitoring-5 (1).png)
• Change packet sizes to see if your network favors small bursts or large payloads
• Persistently test for hours or even days, exposing intermittent problems (network-monitoring-6.png)
• Evaluate switches, routers, and NICs under real-world stress—not just simulated conditions

The results are clear and straightforward. They’re summarized clearly so anyone—automation engineer, technician, or plant manager—can understand and act on them.

Let’s say you’re running OPC Classic across multiple systems. Periodically, a data feed freezes. It restarts after a few seconds or minutes—nobody knows why.

You launch OPC Expert, simulate real traffic using UDP, and leave it running overnight. The next morning, you discover clear evidence: at several intervals, bursts of packet loss and out-of-order delivery were logged. Your network didn’t crash—but it choked.

The diagram above illustrates exactly what’s happening: UDP packets are sent off, and any hiccup—loss, reorder, or delay—is captured with no filters or corrections.

• Automation systems need predictability. If the network fails silently, your systems don’t just lag—they can crash or go into a fault state.
• You can’t fix what you can’t see. UDP traffic reveals the actual state of your network.
• No guesswork. OPC Expert shows you if the problem lies in configuration, congestion, or faulty hardware.

And perhaps best of all—there’s no installation required. Just run OPC Expert on any Windows machine. It doesn’t touch the registry, and it’s free to download.

If you’re tired of chasing phantom OPC errors, it might be time to stop trusting TCP to tell you the truth.

Download OPC Expert and use UDP-based Network Monitoring to see what’s going on. Expose hidden communication problems. Get real data. And finally, fix what’s been eluding your team for too long.