Glossary · Industrial communication
Packet loss
Also known as: Frame loss, Lost packets
German: Paketverlust
In data communication, packet loss is the failure of one or more transmitted packets or frames to reach their destination, caused for example by interference, congestion, faulty cabling or buffer overflows. It is usually expressed as a percentage of sent packets.
- Industrial communication
In one sentence
Packet loss is the share of transmitted packets or frames that never reach their destination, due to interference, congestion or faults.
Example
A wireless link to an AGV shows 2 % packet loss near the rack aisle, so the PROFINET watchdog occasionally stops the vehicle.
How it applies
- Engineering: Real-time protocols tolerate only a few consecutive lost cyclic frames before the connection is considered failed. Wireless links need more tolerance or protocols designed for loss.
- Commissioning: Packet loss is measured under realistic load. Rising error counters on switch ports point to cabling, connectors or EMC problems.
- Operation: TCP-based protocols hide packet loss with Retry mechanisms, which shows up as higher Latency instead. Cyclic UDP-based protocols show it as missed updates or watchdog trips.
- Documentation: The documentation team explains how a product reacts to packet loss (for example how many missed cycles are tolerated and what state outputs take) and which diagnostics show it.
Packet loss vs. latency
Latency is the delay of packets that arrive; packet loss concerns packets that don't. Both matter for control, and a fix for one (more retries) can worsen the other.