Industrial Ethernet is an Ethernet technology used in industrial control. While technically compatible with commercial Ethernet (i.e., the IEEE 802.3 standard), actual products and applications differ significantly. This is mainly because the design of ordinary commercial Ethernet products often fails to meet the needs of industrial environments in terms of material selection, product strength, applicability, real-time performance, interoperability, reliability, interference resistance, and intrinsic security.
What factors should be considered when choosing the right industrial Ethernet switch? Simply put, it includes the industrial Ethernet communication protocol, power supply, communication speed, industrial environment certification, installation method, the impact of the enclosure on heat dissipation, basic communication functions and communication management functions, and whether it uses electrical or optical ports. Other factors to consider include signal strength, port settings, error alarms, serial port usage, trunk (Trunking™) redundancy, ring network redundancy, Quality of Service (QoS), Virtual LAN (VLAN), Simple Network Management Protocol (SNMP), port mirroring, and other functions offered by other industrial Ethernet management switches.
From Rapid Spanning Tree Redundancy (RSTP) and RapidRing™ to Trunking™, industrial Ethernet equipment comprises the following key components:
Industrial Ethernet Hub
Industrial Ethernet unmanaged switches
Industrial Ethernet managed switches
Industrial Ethernet Managed Redundant Switch
Advanced managed redundant switches offer specialized features, particularly optimized for redundant systems with stringent stability and security requirements. The main methods for building redundant networks include STP, RSTP, RapidRing™ ring redundancy, and Trunking.
1. Industrial Ethernet STP and RSTP
STP (Spanning Tree Protocol, IEEE 802.1D) is a link-layer protocol that provides path redundancy and prevents network loops. It forces backup data paths to be in a blocked state. If a path fails, the topology can be reconfigured and the link rebuilt by activating the backup path. Network outage recovery time is between 30-60 seconds. RSTP (Fast Spanning Tree Protocol, IEEE 802.1w), as an upgrade to STP, reduces network outage recovery time to 1-2 seconds. While the Spanning Tree algorithm offers flexible network structures, it also suffers from slow recovery speed.
2. Industrial Ethernet ring network redundancy
To meet the high real-time requirements of industrial control networks, RapidRing was developed. This technology uses ring networks to provide high-speed redundancy in industrial Ethernet networks. This technology allows the network to recover automatically within 300ms after an outage. Users are alerted to network outages through faulty relay connections on industrial Ethernet switches, status indicator lights, and SNMP settings. These features help diagnose where the ring network has broken down.
RapidRing™ also supports two connected ring networks, making network topologies more flexible and diverse. The two rings are connected via dual channels, and these connections can be redundant to avoid problems caused by a single cable failure.
3. Redundancy of Industrial Ethernet Backbone
By configuring multiple ports on different switches as Trunking backbone ports and establishing connections, a high-speed backbone link can be formed between these industrial Ethernet switches. This not only significantly increases the network bandwidth of the backbone link and enhances network throughput, but also provides another function: redundancy. If a problem occurs in the backbone link, data will be transmitted through the remaining links, ensuring normal network communication. The Trunking backbone network uses bus and star network topologies, theoretically allowing for unlimited communication distance. Due to the use of hardware detection and data balancing methods, this technology achieves a new level of network outage recovery time, typically below 10ms.
