In today’s connected world, network reliability is critical for businesses of all sizes. A network outage can lead to lost productivity, frustrated customers, and potentially significant financial losses. One of the most effective ways to enhance network reliability is through redundancy—specifically, implementing redundant links. For those using UniFi networking equipment, creating redundant links can help ensure your network remains operational even when a failure occurs.

This article explores the concept of redundant links, how they work with UniFi devices, and the best practices for setting them up to build a resilient network.

What Are Redundant Links?

Redundant links refer to the practice of using multiple network paths to ensure continuous connectivity. In the event that one link fails, the secondary (or tertiary) link can take over, maintaining network uptime. This redundancy can be applied at various levels, including WAN connections, switches, and even within internal networks to ensure that data has multiple paths to travel.

For businesses, this is particularly important when a reliable internet connection is essential for operations, such as in hotels, offices, retail environments, or any other setting where downtime is unacceptable.

Why Redundant Links Matter

The primary benefit of redundant links is increased reliability. If your network relies on a single path for data transmission, any failure along that path—whether it’s a hardware failure, cable issue, or external outage—will result in downtime. Redundant links eliminate this single point of failure by providing an alternative path for data to travel.

Redundant links also allow for load balancing. By distributing traffic across multiple links, you can optimize network performance and reduce congestion, ensuring a smoother user experience even during peak usage times.

UniFi and Redundant Links: How It Works

UniFi, a popular networking solution from Ubiquiti, offers a range of devices and features that support redundant links. Here’s how you can implement redundancy in a UniFi network:

1. WAN Failover and Load Balancing UniFi Security Gateways (USG) and UniFi Dream Machines (UDM/UDM-Pro) support dual WAN connections, allowing you to configure WAN failover and load balancing.

• WAN Failover: If your primary WAN connection fails, the system automatically switches to the secondary WAN connection, keeping your network online.
• Load Balancing: With load balancing, both WAN connections are active simultaneously, sharing the network load. This improves performance and ensures that both links are utilized, providing redundancy and optimizing bandwidth usage. To set up WAN failover and load balancing, you can configure these options through the UniFi Network Controller. Under the WAN settings, you can assign priority to your primary and secondary WAN connections and enable load balancing if needed.

1. Link Aggregation (LAG) Link Aggregation, also known as LAG or Ethernet bonding, allows you to combine multiple Ethernet links into a single logical link. This provides both redundancy and increased bandwidth. UniFi switches support LAG, allowing you to connect multiple Ethernet cables between switches or between switches and your router. If one link in the LAG fails, traffic will automatically be routed through the remaining links without disruption. To set up LAG on UniFi switches:

• Access the UniFi Network Controller.
• Navigate to the switch settings and select the ports you want to aggregate.
• Enable Link Aggregation on those ports, ensuring that both ends of the connection are configured for LAG.

1. Redundant Power Supplies While not directly related to network links, redundant power supplies (RPS) are another critical aspect of building a resilient network. Many UniFi switches and other devices support RPS, which allows them to stay powered even if the primary power source fails. Implementing RPS ensures that your network devices remain operational during a power outage or failure, further enhancing network reliability. UniFi offers RPS units that can be integrated into your network for this purpose.
2. Redundant Wireless Links If you are using wireless links (such as UniFi’s line of point-to-point wireless bridges) to connect different parts of your network, redundancy is crucial. You can implement redundant wireless links by setting up a secondary wireless bridge that operates on a different frequency or path. If the primary wireless link fails, the secondary link can take over, ensuring continuous connectivity. This can be particularly useful in outdoor environments or campus networks where wired connections aren’t feasible, and wireless links are critical for connecting different buildings or areas.
3. STP (Spanning Tree Protocol) for Loop Prevention When implementing redundant wired links between switches, you must account for potential network loops, which can cause broadcast storms and network instability. UniFi switches support Spanning Tree Protocol (STP), which automatically detects and disables redundant paths to prevent loops. STP allows you to have redundant links in place without worrying about network loops. If the primary link fails, STP will automatically re-enable the redundant link, restoring network connectivity without manual intervention.

Best Practices for Implementing Redundant Links with UniFi

1. Plan Your Network Layout Carefully
   Before implementing redundant links, ensure that your network layout is well-planned. Identify critical points where redundancy is needed and design your network to support multiple paths for data.
2. Test Failover and Redundancy Mechanisms
   After setting up redundant links, test your failover and redundancy mechanisms to ensure they work as expected. Simulate a failure on your primary link and verify that the secondary link takes over seamlessly.
3. Monitor Network Performance
   Use the UniFi Network Controller’s built-in monitoring tools to keep an eye on your network’s performance. Ensure that your redundant links are being utilized effectively and that there are no issues with load balancing or failover.
4. Regularly Update Firmware
   Keeping your UniFi devices’ firmware up to date is essential for maintaining network reliability. Firmware updates often include performance improvements, security patches, and new features that can enhance your network’s redundancy capabilities.
5. Document Your Network Configuration
   Proper documentation is crucial, especially when implementing complex redundancy setups. Keep detailed records of your network configuration, including how redundant links are set up and tested. This will make troubleshooting and future upgrades easier.

Conclusion

Redundant links are a key component of a reliable, resilient network. By implementing WAN failover, load balancing, link aggregation, and redundant wireless connections with UniFi devices, you can ensure your network stays online even when failures occur. While setting up redundancy adds some complexity and cost, the benefits of increased uptime and improved performance make it a worthwhile investment for businesses that depend on a stable network.