Lifting the Lid: Explaining SD-WAN

By GREG HOGGARTH

If your modern business has more than one geographic location, you‘ll have heard the term SD-WAN before. Short for Software-Defined Wide Area Networking, SD-WAN claims include ease of deployment, centralized manageability, reduced costs, improved connectivity, and much more.

So, what is SD-WAN, and what are its most valuable benefits? We talked to Greg Hoggarth from Allied Telesis Labs to find out.

Can you tell us a bit about yourself and what you do at Allied Telesis?

Hi, I’m the Software Development Team Leader for the AlliedWare Plus SD-WAN projects. That involves working with the product owner to determine feature requirements, and then working with the team of software engineers and testers to get SD-WAN implemented and verified.

So, what is SD-WAN?

Broadly speaking, it describes centralized WAN management solutions which offer some form of dynamic, policy-based, application layer forwarding across a group of WAN links. Outside of this very broad definition, each vendor tends to have their own idea of what SD-WAN is, or what it is for their intents and purposes. A podcast I heard recently put it quite well—a customer shouldn’t be looking to see what SD-WAN can do; rather, they should think about what problems they have that need to be solved. And then, find a vendor that can solve those particular pressing needs.

So it’s a needs-based decision, not just buying into the hype of “SD-WAN”—the buzzword?

Right. What are my WAN issues, and how/who best to solve them?

And how does SD-WAN solve WAN issues?

In general, most SD-WAN solutions aim to increase the performance and control of application traffic over redundant WAN interfaces and VPN links by making forwarding decisions based on link quality. They use link probing to determine path quality—latency, jitter, packet loss and so on. Application-aware routing redirects performance-sensitive traffic like video or voice, onto a group of redundant links that meet the application performance requirements. When performance on a given link no longer meets the requirements for a given application, traffic associated with this application is dynamically redirected onto a link that does.

What are the advantages of Allied Telesis Secure SD-WAN?

Allied Telesis Secure SD-WAN simplifies WAN management because we’ve built an SD-WAN orchestrator into our graphical management platform, Vista Manager, to enable visibility and centralized management of all remote locations. Administrators can load-balance inter-branch traffic across multiple WAN links and set acceptable performance metrics for business-critical and real-time applications, so delivery is assured, and performance is automatically optimized.

Once SD-WAN is up and running, the orchestrator then lets users easily monitor the WAN, with the ability to drill down and see the operation and status of specific WAN links or applications. So network administrators can be confident that SD-WAN is improving application throughput, view changes in WAN link use over time, and be proactive in making any changes to application management in line with business needs for the best possible performance.

How does SD-WAN reduce costs?

Allied Telesis SD-WAN is secure because we use UTM firewalls as our endpoints, so application-layer security inspection can occur at branch sites—providing WAN security and WAN traffic optimization solution in a single device. That’s a definite savings of both money and time for any customer.

Additionally, the ability to replace existing MPLS links with encrypted tunnels potentially offers some significant cost savings. Businesses can replace expensive dedicated inter-branch MPLS links with multiple low-cost Internet links instead, with SD-WAN providing the intelligence to maximize the performance of the WAN.

How does SD-WAN replace MPLS?

Okay, so two of the most dominant site-to-site WAN technologies in-use today are encrypted tunnels over an internet connection (VPN links) and MPLS. Encrypted tunnels over an internet connection are cheap and flexible but suffer from variable latency rates and packet-loss, which makes them unsuitable for carrying performance-sensitive traffic such as voice and video.

Because of this, historically MPLS links were used when performance-sensitive traffic was transmitted between sites. MPLS links are significantly more expensive, but have Service Provider-guaranteed link performance.

SD-WAN reduces the need for MPLS links by using a probing mechanism to determine the performance of a given tunnel. If the tunnel’s performance doesn’t meet the requirements of an application, then traffic associated with that application is dynamically redirected onto one that does.

Who can benefit from SD-WAN?

Any modern business with multiple locations, although particularly those using expensive conventional WAN links. These can be replaced with an SD-WAN solution to reduce both the cost and complexity of WAN management, while automatically optimizing inter-branch traffic performance and application delivery—there’s really no downside.

Allied Telesis SD-WAN can help your business

SD-WAN is a fast-growing market—traditional, old-style WANs don’t really meet modern digital business needs. Allied Telesis SD-WAN is driven by the need for dynamic and automated management supporting high-performance WAN connections. These enable today’s applications to support business operation, with better connectivity to customers and a better end-user experience.

Want to know more? Explore our Secure SD-WAN solution.