A Best Practices Guide to Updating Legacy Network Architectures

Today’s businesses can choose from more advanced networking solutions than ever before, in more places than ever before. But this doesn’t necessarily translate to better networks across the board. That’s because many organizations have networks that they’ve pieced together over time, often using outdated components and architectures designed to serve applications that are no longer in use.

When enterprises build piecemeal networks like this, there’s no high-level strategy to optimize for performance, flexibility and reliability across the company’s distributed operations. As the digital business landscape changes with the emergence of agentic AI and other groundbreaking technologies, these companies won’t have the agility needed to capitalize on these opportunities.

To create a network that’s optimized for today and ready for whatever tomorrow brings, IT leaders must first untangle their various legacy components and replace them to address the underlying technical debt. However, this is typically easier said than done.

Why is updating legacy networks so difficult?

When you’ve done things a certain way for years and it seems to work well enough, it’s only natural to preserve the status quo. The problem is that your network may not be working as well as you think it is. If you look closely at your legacy network, you may detect inefficiencies that you’ve never considered before.

In other cases, IT leaders have inherited networks that they know are poorly designed, but they don’t always know what to do about it. The thought of ripping up their existing network and starting over from scratch is unappealing, but they know that something has to be done.

If you’re unsure how to update your legacy network, then you’re not alone. Network modernization is a challenge facing many companies today. It’s something I see frequently in my role working with Equinix customers. These experiences have given me a better understanding of how to proceed in these situations.

5 steps to address shortcomings in your legacy network

Below, I’ll summarize the five steps that businesses can take to start updating their legacy network infrastructure today.

1.     Start with “why”

Despite how it might seem, there is a reason your network looks the way it does—or more likely, multiple reasons. The problem is that these reasons are known only to those who implemented the legacy components years ago. Your job is to put yourself in their shoes. Research your network timeline to identify when specific components were added and why.

Most legacy networks include components meant to satisfy requirements that haven’t been relevant for years now. These components stayed in place simply because nobody took the time to find and remove them.

There are probably also workarounds intended to address infrastructure limitations that no longer exist. For instance, many legacy networks were designed at a time when small, unreliable connections were the norm. As a result, many networking leaders implemented traffic patterns that prioritized voice calls.

These patterns no longer make sense at a time when network bandwidth is essentially limitless. We can design things better because we no longer need workarounds to ensure reliable voice calling. This is an optimization opportunity that you would only know about after you figure out why your network was designed that way in the first place.

2.     Make incremental progress by prioritizing the biggest issues first

Instead of trying to rebuild your entire network from scratch, start by addressing only the major networking problems. To do that, ask yourself the following questions:

• What are the legacy components that are causing the most problems for the organization today?
• How can I get them offline as quickly as possible while minimizing disruption?

You may need an outside perspective to help uncover the issues hiding in plain sight. For example, I recently worked with a major pharmaceutical company that was running a legacy on-premises security stack. This security stack was acting as a bottleneck that impacted performance across the entire network. All traffic had to be routed through it, regardless of origin or destination.

They may have known that this architecture was not ideal, but they didn’t realize it was so bad they needed to take immediate action. They had to see it on a whiteboard before it dawned on them just how inefficient this setup was.

3.     Optimize for proximity—now and later

Proximity between infrastructure and workloads will always be relevant in any network architecture discussion. In fact, we can safely assume that future applications will continue growing more latency-sensitive, so it makes sense to design for low latency today.

In the steps above, you may have identified legacy components or workarounds that have kept you from truly optimizing your network architecture. Now’s your chance to do something about that.

Going back to my previous example, the pharma company was connecting to cloud regions located hundreds of miles away from their on-premises infrastructure. Once they realized how much latency they were creating by routing traffic all the way though their on-premises security stack and all the way back to the cloud, they knew they could do better. They saw that they could remove the bottleneck by deploying new security infrastructure closer to their cloud regions.

4.     Get everyone on the same page

When it comes to network modernization, poor communication is often just as big of a blocker as technical limitations. When different teams aren’t clearly communicating with one another, it’s essentially impossible for them to align on what the problem is and how to solve it.

It’s important to avoid finger-pointing that will only lead to further breakdowns in communication. But if you start to realize that one team or business function is dominating network strategy within the organization, then you may need to have some tough conversations.

At the pharma company mentioned above, the network and application teams were hesitant to second-guess the security team, and they naturally assumed that taking the security stack offline might introduce unnecessary risk. At the same time, the security people weren’t the best judges of what constitutes a modern, efficient network. When we got them all in the same room, they realized they could redesign their network in a way that would meet everyone’s needs.

5.     Design with neutrality in mind

Neutrality wasn’t always a concern back when many legacy networks were first built. In the early days of cloud, many companies had no problem going all-in with a single provider. In turn, they likely never considered the need for true multicloud networking capabilities.

Over time, they’ve learned the hard way how problematic that decision was, especially now that leveraging multiple cloud and SaaS providers has become much more common than using only a single cloud provider. They now recognize the need to move data between clouds to optimize performance and flexibility, but their network isn’t set up to do that.

It’s too late to undo the original decision. The next-best thing is to make the right decision today, so that you’ll have the flexibility to meet changing needs in the future. A true multicloud approach requires deploying in a neutral infrastructure environment with access to multiple cloud on-ramps.

Modernize your network at Equinix

Inside an Equinix IBX® colocation data center, you can build the neutral environment you need to prepare for the future of multicloud. You can deploy your data and workloads inside a private environment that you control, while also connecting to multiple clouds on demand.

Using Equinix Fabric®, our virtual interconnection solution, you can quickly stand up the connections you need and scale them any time your needs change. This can replace physical network infrastructure that locks you into a certain way of doing things.

Since Equinix operates 270+ data centers across six continents, we make it easy to deploy in proximity to your data sources, end users and ecosystem partners.

Learn what an optimized multicloud networking strategy looks like: Get your copy of Hybrid Multicloud Networking for Dummies today.