SD WAN over a typical WAN?

Even before the pandemic changed the way that almost all companies work and utilise IT, SD WAN solutions were growing in popularity. Organisations with heavily (or increasingly) engrained cloud infrastructure were choosing to supplement firewalls with an SD WAN to significantly enhance cloud-hosted application performance and user experience, all while reducing IT costs and retaining the security and privacy afforded by traditional WANs.

For example, a business with c-suite executives working from disparate locations or remote colleagues accessing business-critical applications or sensitive data is likely to prefer an SD WAN over a typical WAN.

The latest SD WAN solutions offer a complete “network in a box” solution to achieve secure and seamless connectivity to various sites, applications, hardware and routers – such as connecting to third party suppliers, point of sale units, cloud storage and data centres. This is in addition to significantly improved video streaming quality and IP telephony and the provision of business grade internet for any on-premise user.


Why is SD WAN better for the cloud?

But is SD WAN better for the cloud? If applications or data are hosted in the cloud, SD WAN offers lower costs, increased bandwidth and network availability, higher application performance and easier network management for businesses with multiple sites. Keep reading and we’ll explain why in more detail.


What is the definition of SD WAN?

SD WAN stands for Software-defined Wide Area Network. It is an intelligent, virtual WAN architecture that uses a centralised control function that harnesses connectivity services such as broadband internet and multi-protocol label switch (MPLS) to securely and efficiently connect users to applications, virtual devices, hardware devices, cloud environments, IoT devices and much more.


How does an SD WAN work?

The SD WAN solution emerged to make WAN more intelligent, flexible and resilient while still utilising broadband links to the internet in the way that MPLS does. Unlike MPLS though, its policies can be easily applied across all WAN devices without the need for predetermined routes terminating at a hub – more on that later. (Anchor link)

An SD WAN takes everyday internet lines and creates a permanent, secure tunnel between sites. This essentially results in grouping multiple internet connections together as one and allows for businesses to connect sites spread over distances for the purpose of sharing data, apps and services.

An SD WAN is also capable of providing application-aware routing across the WAN, which means that each application receives appropriate performance, quality of experience and security in line with business requirements. Essentially, this allows smaller sites within distributed organisations to build, operate and manage high-performance networks using readily available, low-cost public internet services while enhancing the functionality of cloud-based apps and protecting against cyberthreats.


Why is SD WAN better for the cloud



First, a brief terminology overview. A WAN is a type of telecommunications network that connects devices from multiple locations across the globe, the most famous being the internet. When we refer to traditional WAN, we talk about the old school method of connecting multiple branch offices to one another through VPNs that pass through and terminate at head office. This means that if head office is down, branch offices will experience network downtime, or poor speed and accessibility.

This is an obvious pitfall that, in an era of digitised business, makes a traditional WAN solution generally unviable. As a remedy, organisations began using MPLS instead. This is an alternative method of using leased lines to route traffic through a network which also increases speed and better controls the flow of network traffic.

MPLS sends all traffic – associated with both head office and branch offices – down a predetermined path, terminating at a virtual hub. Using lines leased from an internet service provider, MPLS provides a secure, managed link between branch offices and a data centre. This delivers a reliable, fixed level of bandwidth, availability, and security to all sites, even if head office is down.

However, using MPLS to achieve resilience quickly becomes expensive. Line providers put a high price tag on in-built service levels and at the same time, varying performance requirements of today’s traffic means organisations must lease lines for their worst-case-scenario traffic load. So, expensive bandwidth is wasted or rigid MPLS connections struggle to manage the advanced interconnectivity of modern networks and devices. And even when MPLS is the perfect functional solution, it is unnecessarily costly!

Thankfully, there’s a better way. In addition to offering better visibility, availability, uptime, performance and provisioning capabilities, SD WAN does not come with the requisite, expensive MPLS service levels despite utilising broadband links to the internet.

So people started turning to SD WAN to get the same availability, performance and security benefits but without continuing to pay for expensive MPLS service levels. It is a way to achieve resiliency above and beyond what MPLS delivers.


What can SD WAN do differently?

SD WAN is smart. Unlike traditional WAN or MPLS, SD WAN can understand the nature of the traffic it is handling. It recognises applications and dynamically adapts bandwidth accordingly, using features such as application recognition and traffic shaping to prioritise latency-sensitive traffic such as video and voice.

In addition to boosting user experience and productivity, these next-generation features help IT departments achieve consistent performance and availability of business-critical and SaaS applications while securing traffic from advanced threats across an entire network. Basically, applications (latency-sensitive or not) get all the horsepower they need.

SD WAN also uses a far more cost-effective manner of processing and distributing traffic than MPLS or a traditional WAN setup. But be wary – not all SD-WANs are created equally. A true SD WAN will dynamically and intelligently route traffic. A solution that only load-balances traffic is SD WAN in name only.



SD WAN and cloud

Simply put, traditional WAN or MPLS were never designed for the cloud and SD WAN was! These connectivity solutions are based on conventional routers and in a digital-first world that is full of surprises, the cloud (whether private, public or a combination of both) is fundamental to business resilience. Therefore, SD WAN was created to support apps hosted on-premise, public and private cloud and via SaaS in the best way possible.

A traditional WAN forces what is known as “backhauling”. This is when network traffic including that communicating with the cloud is passed from offices to a datacentre at HQ where security inspection takes place. This cost-inefficient process inevitably causes a delay and subsequently impacts IT performance and increases latency. SD WAN resolves these issues.

SD WAN adds exceptional value and improved functionality for any company needing to work flexibly, as a means of mitigating operational disturbance or any slowdown consequences of remote working. It gives users secure, local access to services they need while securing direct access to cloud resources while delivering increased network availability and higher application performance. As a result, businesses utilising cloud infrastructure benefit from increased productivity and streamlined costs when supporting a remote or flexible workforce.

You can also use an SD WAN to…

  • Achieve unlimited busines-grade internet
  • Offer secure guest WiFi
  • Connect to third party suppliers and distributers
  • Connect to POS units and security cameras


What to look for in an SD WAN

As mentioned, some SD WAN solutions are all but a name and fail to meet the minimum service attributes to be classified as true SD-WAN. Only with true SD WAN will you receive all benefits at an affordable price – approximately 1/3 of the cost of an equivalent MPLS. Here is what to look for in an SD-WAN:


  • must be a secure, IP based transport independent overlay network,
  • with application driven and policy based dynamic packet forwarding
  • within service assured high availability tunnels
  • across multiple WANS
  • and with service automation via centralised management,
  • control and orchestration,
  • and may also offer WAN optimisation functionality



Why are businesses turning to SD-WAN?

Many organisations were already in the advanced stages of cloud adoption, and the vast majority were harnessing some sort of cloud capability – from SaaS apps to cloud storage and collaboration tools. As such, an SD WAN solution is fast becoming a security and connectivity must-have. And with achieving resilience, mitigating disruption and enabling remote working now acute objectives, more businesses than ever are accessing apps, critical data and productivity tools via the cloud.

With true SD WAN available for even the smallest stores, sites and networks, literally every company and user can benefit from fast, highly available and cloud-ready networking.

There has never been a more sensible or strategic time to introduce SD WAN to your IT infrastructure and phase out MPLS. (We’ve mentioned it already, but a quick reminder that SD WAN can reduce IT costs too – a welcome relief for any company at present). Are you considering switching to an SD WAN or do you need help aligning your IT with the new world of working? If so, please click here to speak to a consultant or call +44 844 579 0800.

by Craig Bradshaw

Head of Account Management

A technology enthusiast working in the Technology industry for almost 20 years, looking to deliver exceptional customer experience.