In today’s world, where every aspect of business depends on IT, and downtime is measured not only in lost revenue but also in missed opportunities and reputational damage, connection stability becomes a critically important factor. From email and internal CRMs to online sales and cloud services — all of it requires constant and reliable network access.

This is where network link redundancy comes into play. It’s not just “insurance” — it’s a fundamental part of your business continuity and high availability strategy for your IT infrastructure.

What is network link redundancy?

Network link redundancy means creating redundant network paths and hardware so that if a primary component fails, traffic automatically or semi-automatically switches to a backup, minimizing or completely avoiding disruptions.

The main goal of redundancy is to ensure your business stays connected even when something goes wrong.

Why does connectivity fail? (Sometimes unexpectedly)

There are many reasons a connection might fail — and not all of them are obvious:

• Cable cuts: The most common cause. This could be a mainline cable on the street (due to construction, vandalism, or natural events), or a patch cord inside a server room, accidentally unplugged or damaged.
• Provider equipment failures: Failures of routers, switches, or other network devices on your internet provider’s side.
• Natural disasters: Floods, earthquakes, and severe storms can damage communication infrastructure across wide areas.
• Human error: Mistakes in equipment configuration, incorrect connections, forgotten passwords.
• DDoS attacks: Targeted attacks that can overload your connection or equipment, rendering it inaccessible.
• Software failures: Bugs in the firmware of network devices or operating systems.

Consequences of no redundancy: the cost of downtime

If you’re thinking, “That won’t happen to us” or “We can survive a couple of hours without internet,” consider the potential consequences:

• Financial losses: Direct losses from halted sales, inability to process transactions, or employee downtime.
• Reputational risks: Clients can’t access your services, partners can’t reach you. This undermines trust and may lead to customer churn.
• Business stoppage: No access to cloud resources, internal servers, or databases. In today’s world, this often means a complete halt for many companies.
• Data loss: In some cases, a network failure may lead to improperly completed operations, resulting in data loss or corruption.
• Missed opportunities: You’re unable to respond quickly to market changes, handle requests, or seize new opportunities.

Key principles of redundancy

To effectively protect against network failures, you need to follow several key principles:

1. Redundancy: Have more than one of everything. Two network interfaces instead of one, two switches instead of one, two internet providers instead of one.
2. Diversity:
   • Technologies: Use different technologies (e.g., fiber and radio, Ethernet and Wi-Fi).
   • Providers: Use different internet service providers.
   • Routes: Ensure physical cable routes are different (e.g., cables enter the building from different sides).
3. Failover: Ideally, the system should automatically detect a failure and switch to the backup connection without manual intervention. This minimizes downtime.
4. Monitoring: Continuous monitoring of all communication channels and equipment. Only then can you promptly detect issues and evaluate redundancy effectiveness.

Types of redundancy

Depending on your strategy, redundancy may be:

• Active/Passive: One link is primary, the other is backup and only activated upon failure of the first. Easier to configure, but the backup sits idle.
• Active/Active: Both links are active and used simultaneously for load balancing or increased bandwidth. If one fails, the other continues operating under increased load. Harder to configure, but more efficient resource usage.

What’s next?

Network redundancy isn’t a one-time action, but a comprehensive approach that should be tailored to your infrastructure’s specific needs. Depending on the type of connection, solutions will vary significantly.

In our article series, we’ll explore various redundancy scenarios and methods in detail:

• Server-to-server connections in the same building: How to ensure reliable LAN and in-data-center connections.
• Office-to-office links: How to connect geographically distributed branches with maximum resilience.
• Internet connectivity: How to maintain uninterrupted access for your web services and data centers.

Stay tuned to learn how to make your infrastructure truly resilient!