What Is Network Redundancy? How to Implement Redundancy in Industrial Switches?

In network communication - whether it's home WiFi or an industrial communication system - a failure in a core device or link can cause widespread device outages and service interruptions. In industrial settings, a network failure could even lead to production halts or critical data loss. The core value of network redundancy lies in eliminating single points of failure through backup mechanisms, ensuring continuous network availability. This article systematically explains the logic behind redundancy in networking, with a focus on redundancy in industrial switches, exploring key designs and implementation strategies.

What Is Network Redundancy?

Simply put, network redundancy is about being prepared. It's the idea of having one or more backup systems in place. In communication systems, redundant networking ensures that if part of the network fails, an alternate path or device can take over, allowing the network to continue operating smoothly.

Also referred to as a failover solution, redundancy in network design is especially critical in high-availability environments. In industrial networks, redundancy in computer network systems is not just a technical optimization - it's a foundational requirement for continuous operation.

Types of Network Redundancy

Device Redundancy

Link Redundancy

Ring Redundancy

Gateway Redundancy

These strategies can be deployed independently or combined to build a truly redundant network architecture.

Device Redundancy: Dual Protection for Critical Equipment

The concept of device redundancy is straightforward: equipping critical devices with a "backup" so that when the primary device malfunctions, the backup device immediately takes over to prevent service interruptions.

There are two common methods of device redundancy:

Hot Standby: The backup device is "always online" and continuously synchronizes data with the primary device. In the event of a primary device failure, it immediately takes over the task, with the entire switching process occurring almost seamlessly. This is commonly used in core switches, main controllers, and other critical nodes and can also be used for load balancing, where two devices process tasks simultaneously to improve efficiency. With hot standby, the system can seamlessly switch to the backup switch when the primary switch fails, ensuring network connectivity and stability.

Cold standby: The backup device remains in a "standby state" and does not actively run. When the primary device fails, the backup device is manually or system-triggered to activate. Although the response speed is slower than hot backup, the implementation cost is lower, which is suitable for certain scenarios that do not require high real-time performance.

Whether it is hot standby or cold standby, the essence is to improve the stability and fault tolerance of the system. It is very common in industrial applications, and hardware redundancy mechanisms are also commonly used in switches to enhance reliability. For example:

Redundant power supply design: The switch is configured with two or more independent power input interfaces, and these two power circuits are usually independent of each other and supply power independently. If one power supply encounters issues (such as power loss, unstable power supply, or loose connections), the other power supply can seamlessly take over the power supply task, ensuring the switch continues to operate without interruption.

Support for hot-swappable components: Hot-swappable technology allows hardware components to be inserted or removed while the device is powered on, without shutting down the system. Our rack-mount switches support multiple hot-swappable dual power modules. A key advantage of this design is that if a power module fails, the user can replace it without shutting down the device - simply remove the failed module and insert a new one. This process does not affect ongoing device operations, significantly reducing network downtime caused by maintenance operations.

Link Redundancy: Multiple "Highways" for Data

In industrial communication environments, link aggregation is an important redundancy and performance enhancement technology. By binding two or more physical links into a single logical link, industrial switches can not only increase total bandwidth but also implement link-level fault tolerance mechanisms. When one of the links fails, the system automatically switches data traffic to other available links without manual intervention, ensuring uninterrupted communication. You can think of it as “bundling multiple network cables together to form a wider channel.” Just as a thick cable contains many thin copper wires, even if one of them breaks, the current can still flow normally. This concept is the cornerstone of redundancy in critical system network design.

Ring Network Redundancy: Using a Closed Loop to Address Link and Device Failures

Ring network redundancy is an advanced form of link redundancy. Its core principle is to use a "ring topology" design and dedicated protocols to solve communication interruption problems caused by the failure of a single link or device. In industrial networks, switches are connected in a ring configuration to form a closed loop, enabling data to be transmitted in both clockwise and counterclockwise directions. When a segment of the link or a device fails, data can automatically reroute via the other direction, preventing the entire network from becoming paralyzed.

The key to ring network redundancy lies in "loop prevention" and "rapid switching." Without dedicated protocol control, a ring topology could trigger a broadcast storm (where data loops infinitely within the ring). Therefore, industrial switches must use protocols to identify failures, block redundant paths (under normal conditions), and activate backup paths (during failures). Common ring network redundancy protocols include:

RSTP (Rapid Spanning Tree Protocol): Provides faster convergence than traditional STP, switching paths within seconds.

MSTP (Multiple Spanning Tree Protocol): Allows multiple VLAN paths, improving bandwidth utilization.

ERPS (Ethernet Ring Protection Switching): An ultra-fast protocol tailored for industrial rings, offering sub-second failover.

MW-Ring (Proprietary Fast Ring Protocol): A proprietary protocol designed by our company for industrial control networks. It provides fault recovery within 20ms and features simple configuration for ring ports and fast fault transfer.

These protocols can automatically activate backup paths when a link or device failure is detected in the network, ensuring uninterrupted data flow and greatly improving the network's fault tolerance and recovery speed.

Gateway Redundancy: No Fear of "Entry/Exit" Failure

In network communication, communication between different subnets or network segments is typically accomplished through a gateway. A gateway can be understood as the "exit" or "high-speed entry" of a network. If this "entry/exit" fails, the entire network will be in a state of communication interruption.

To solve this problem, a commonly used solution is to adopt a technology called VRRP (Virtual Router Redundancy Protocol).

The ingenuity of VRRP lies in the fact that it does not simply assign two different IP addresses to devices but instead establishes a "virtual gateway." This virtual IP address appears to be a real device, and all terminal devices default to using this virtual IP address as the gateway.

In practice, this virtual gateway is maintained by two or more devices. One is the "primary device," and the other is the "backup device." The primary device handles normal data forwarding, while the backup device remains in monitoring mode. If the primary device fails, the backup device automatically takes over the virtual gateway IP, ensuring a seamless transition.

The Benefits of Network Redundancy

So, what are the benefits of building redundancy into a network?

Implementing redundancy in networking provides a wide range of advantages, especially for mission-critical environments like industrial automation, smart transportation, and real-time monitoring systems. Key benefits include:

Improved Network Reliability

By eliminating single points of failure, a redundant network ensures that even if one component or path fails, the system continues to operate normally. This is critical in sectors where downtime can result in significant financial or safety consequences.

Uninterrupted Business Operations

A redundancy network allows for automatic failover and fast recovery, minimizing service interruptions. This ensures that essential applications and services remain accessible without manual intervention, even during outages.

Increased Network Security

In some cases, redundant in networking also strengthens security by providing multiple paths for encrypted data or isolating backup systems to contain attacks or faults.

In short, the benefits of redundancy in a network go far beyond simple fault tolerance - they create a more agile, secure, and efficient infrastructure capable of meeting the demands of modern digital operations.

Conclusion

In short, network redundancy is not just a technical choice, but also a risk response strategy. In industrial environments, whether it is equipment redundancy, link redundancy, ring network redundancy, or gateway redundancy, the ultimate goal is to achieve "uninterrupted operation." In industrial settings, the integrated application of these technologies can minimize the risk of production downtime, serving as the "lifeline" of modern industrial communication. By reasonably planning and deploying redundant architectures, enterprises can not only effectively reduce the risk of unexpected downtime but also enhance the overall reliability and maintenance efficiency of communication systems, providing a solid foundation for applications such as smart manufacturing and automated monitoring.