Understanding Latency and Jitter in Industrial Ethernet Networks

As industrial automation, smart manufacturing, and the Internet of Things (IoT) continue to evolve, ensuring the accuracy and stability of real-time communication becomes increasingly important. This article explores the key concepts of latency and jitter and explains how industrial switches effectively manage these issues.

Key Concepts of Latency and Jitter

Latency

Latency refers to the time delay between the sending and receiving of data packets in a network. It is measured as the time taken for a data packet to travel from its source to its destination. Transmission delays can be introduced by physical components of the network, such as cables and switches, as well as delays caused by routing through electrical and electronic pathways. High latency can lead to delays in data transmission, which can be detrimental in time-sensitive industrial applications where real-time responses are crucial.

Jitter

Jitter is the variation in the time delay of received data packets. It occurs when packets take different amounts of time to travel from the source to the destination, causing fluctuations in the arrival times of the packets. Strictly speaking, jitter is the variation in latency above the upper limit. High jitter can result in uneven data flow, which can disrupt the synchronization and coordination of industrial processes. In motion control applications, where the output of a message controls a process, jitter can be even more critical to the application than the network’s speed.

How Industrial Switches Manage these Issues

Industrial switches play a vital role in managing and minimizing latency and jitter in Ethernet networks. They incorporate various features and technologies designed to enhance network performance and ensure reliable real-time communication.

Traffic Prioritization and QoS

Industrial switches use Quality of Service (QoS) mechanisms to prioritize critical data traffic. By assigning higher priority to time-sensitive data packets, switches ensure that these packets are transmitted with minimal delay. This prioritization helps reduce latency and provides a more consistent data flow, thereby minimizing jitter.

Time-Sensitive Networking

Time-Sensitive Networking (TSN) is a set of IEEE 802.1 standards that enhance Ethernet networks for real-time applications. TSN ensures deterministic communication, meaning that data packets are delivered within a guaranteed timeframe. This is particularly important for applications requiring precise timing and coordination, such as industrial automation and autonomous driving.

The TSN3220-10S-U industrial switch from FS is a prime example of TSN technology. This switch supports IEEE 802.1AS for precise time synchronization, IEEE 802.1Qbv for traffic scheduling, and IEEE 802.1Qcc for stream reservation. It is designed for a wide range of industrial applications, providing robust performance in harsh environments.

Advanced Traffic Management Features

Industrial switches also incorporate advanced traffic management features such as VLANs, IGMP Snooping, and LACP. VLANs (Virtual Local Area Networks) help segment network traffic to reduce congestion and improve data flow efficiency. IGMP Snooping ensures efficient multicast traffic management, reducing unnecessary data transmissions. LACP (Link Aggregation Control Protocol) allows the combination of multiple network links to increase bandwidth and provide redundancy, further enhancing network reliability.

High-Performance Hardware and Redundant Design

Industrial switches are built with high-performance hardware capable of handling large volumes of data with low latency. They often feature redundant power supplies and network paths to ensure continuous operation even in the event of a failure. For example, the IES3110-8TFP-R industrial switch from FS is designed for rugged environments, offering 8x 10/100/1000BASE-T PoE+ ports and 2x 1G SFP ports. It supports IEEE 1588v2 PTP for precise time synchronization and includes enhanced L2+ functions such as VLAN, QoS, and LACP. Its robust design ensures reliable performance and minimal latency in demanding industrial settings.

Conclusion

Effective management of latency and jitter is vital for maintaining the performance and reliability of industrial Ethernet networks. Industrial switches play a key role in this process, leveraging advanced features to ensure accurate, real-time communication.