Packet loss
Packet loss is the phenomenon in which data packets are lost during network communication before reaching their destination. Within OT and industrial automation environments, packet loss can have serious consequences for real-time communication, process control, monitoring and system availability.
In modern industrial networks, thousands of devices communicate continuously via protocols such as:
When data packets are lost, systems may:
- Respond with delay
- Display incorrect data
- Lose connections
- Operate unreliably
- Disrupt production
Within IT OT Convergence, packet loss is becoming increasingly important due to growing network load, cloud connectivity and real-time analytics.
⚙️ What is packet loss?
Network communication takes place via data packets.
A packet contains:
- Source address
- Destination address
- Payload
- Control information
Packet loss occurs when a packet:
- Does not arrive
- Becomes corrupted
- Arrives too late
- Is discarded by network equipment
The loss rate is usually expressed as a percentage of all packets sent.
Example:
| Sent | Lost | Packet loss |
|---|---|---|
| 10,000 | 100 | 1% |
Even small percentages can have a major impact in OT environments.
🌐 Causes of packet loss
Packet loss can have various technical causes.
Network congestion
The most common cause is Network Congestion.
When the network load exceeds the available bandwidth, buffers fill up and packets are dropped.
Poor cabling
Physical problems often cause errors.
Examples:
- Damaged cables
- Faulty connectors
- EMC interference
- Poor earthing
In industrial environments, electromagnetic interference is a significant cause.
Overloaded network equipment
Problems arise with:
OT equipment often has limited processing capacity.
Wireless issues
Wireless networks are more susceptible to packet loss.
Examples:
Issues:
- Interference
- Signal loss
- Channel overlap
- Obstructions
Configuration errors
Poor configurations regularly cause packet loss.
Examples:
- Duplex mismatches
- MTU problems
- Incorrect QoS settings
- Broadcast storms
🏭 Impact in Industrial Automation
Within Industrial Automation, packet loss has direct operational consequences.
Process control
Loss of process data can lead to:
- Unstable control loops
- Incorrect measurement values
- PLC timeouts
- Incorrect actuation
Motion Control
In motion control, packet loss can lead to:
- Synchronisation problems
- Position errors
- Vibration
- Safety stops
SCADA systems
Within SCADA, problems arise such as:
- Delayed trends
- Missing HMI data
- Alarm delays
- Communication errors
Historian systems
Packet loss causes:
- Missing data
- Disrupted trends
- Unreliable analyses
⚡ Real-time communication and packet loss
Many OT networks require deterministic communication.
Key factors:
Real-time protocols such as ProfiNET and Ethernet IP are sensitive to packet loss.
Even small disruptions can:
- Cause scan cycle errors
- Disrupt real-time synchronisation
- Affect motion systems
📡 Packet loss in industrial protocols
Not all protocols respond to packet loss in the same way.
| Protocol | Sensitivity |
|---|---|
| TCP | High recovery capability |
| UDP | No recovery |
| MQTT | QoS-dependent |
| OPC UA | Medium |
| Modbus TCP | High |
TCP
TCP retransmits lost packets.
Advantages:
- Reliability
Disadvantages:
- Higher Latency
- More overhead
UDP
UDP does not retransmit.
Advantages:
- Low latency
Disadvantages:
- Higher sensitivity to loss
For this reason, real-time protocols often use specialised recovery mechanisms.
🧠 Packet loss and QoS
QoS helps to prioritise critical OT traffic.
Advantages:
- Less congestion
- Less packet loss
- Better real-time performance
Priority is often given to:
- PLC traffic
- Motion control
- Alarms
- Safety communication
Lower-priority traffic:
- Backups
- Video streams
- Historian exports
📈 Detection and monitoring
Packet loss must be actively monitored.
Key monitoring methods:
| Method | Function |
|---|---|
| Ping tests | Basic loss |
| SNMP | Interface metrics |
| NetFlow | Traffic analysis |
| Wireshark | Packet inspection |
| Network Monitoring | Continuous monitoring |
Key metrics:
- Packet drop rate
- Retransmissions
- CRC errors
- Interface utilisation
- Queue overflows
Monitoring platforms:
🔄 Packet loss versus latency and Jitter
Although related, these concepts differ fundamentally.
| Aspect | Packet loss | Latency | Jitter |
|---|---|---|---|
| Meaning | Loss | Delay | Variation |
| Impact | Data loss | Slow | Unstable |
| Cause | Congestion/errors | Distance/load | Timing variation |
In OT, all three can cause serious problems.
🔐 Cybersecurity and packet loss
Cybersecurity incidents can cause packet loss.
Examples:
| Attack | Effect |
|---|---|
| DDoS | Network saturation |
| Malware scans | Overload |
| Broadcast attacks | Congestion |
| Rogue devices | Excessive traffic |
In addition, security measures themselves can introduce packet loss.
Examples:
- Deep packet inspection
- IDS analysis
- Overloaded firewalls
- SSL inspection
Security solutions must therefore be carefully designed within real-time OT networks.
🚨 Failure modes in OT
Packet loss can lead to critical operational problems.
Common failure modes:
| Problem | Consequence |
|---|---|
| PLC communication timeout | Production stop |
| Loss of I/O data | Process instability |
| Lost HMI | Poor operability |
| Alarm delay | Safety risk |
| Historian gaps | Incomplete analyses |
Within critical infrastructures, these effects can have a direct safety impact.
⚠️ Wireless OT networks
Wireless industrial networks often have higher packet loss.
Key causes:
- Reflections
- Metal structures
- Electromagnetic interference
- Overload
For this reason, wired networks are often used for critical real-time applications.
Wireless solutions require:
- Site surveys
- Redundancy
- Channel planning
- Signal monitoring
🧩 Redundancy and fault tolerance
Modern OT networks use redundancy to limit packet loss.
Techniques:
| Technology | Function |
|---|---|
| Redundancy | Backup paths |
| RSTP | Recovery after failures |
| PRP | Parallel networks |
| Ring topology | Alternative routes |
Real-time industrial networks often use protocol-specific redundancy mechanisms.
☁️ Cloud and hybrid OT networks
Cloud integration increases the risk of packet loss due to:
- WAN connections
- Internet latency
- Variable network load
Key mitigations:
- Edge Computing
- Local buffering
- MQTT QoS
- Data caching
Real-time control therefore generally remains local within OT networks.
🔄 Packet loss versus errors
Not all network faults lead directly to packet loss.
| Issue | Consequence |
|---|---|
| CRC errors | Corruption |
| Packet loss | Loss |
| Retransmissions | Recovery attempts |
| Timeouts | Broken communication |
Diagnosis therefore requires in-depth network analysis.
🏗️ Packet loss in IT/OT convergence
Within IT OT Convergence, sensitivity to packet loss is growing due to:
- More connected devices
- Cloud analytics
- IIoT
- Video monitoring
- Security Monitoring
For this reason, modern OT networks are designed with a focus on:
- QoS
- Segmentation
- Redundancy
- Monitoring
- Capacity planning
Packet loss thus represents a critical indicator of network health, real-time reliability and operational stability within modern industrial infrastructures.