The Internet is like a many-layered cake. The more layers you have the more ingredients it takes and the greater the potential costs. In recent times this is why SD-WAN has come to be something of flavour of the month. So let’s look at what it is, how it sits within the wider IP infrastructure and the potential benefits it brings to businesses.
A Quick Recap on SD-WAN
SD-WAN is the implementation of Software Defined Networking concepts to the Wide Area Network. This typically means the deployment of SD-WAN network devices that can apply rules and implement policies to send traffic along the best path, via the public/open internet as opposed to the more costly-to-implement Multi-Protocol Label Switching (MPLS) network.
As Ethan Banks puts it, “Stitching together remote offices via a provider’s MPLS network is highly functional — with L2 or L3 connectivity options and guaranteed privacy and quality of service — but also expensive.” [ source : https://www.networkcomputing.com/networking/software-defined-wan-primer]
The History Bit
This isn’t to suggest that there is no place for MPLS. It remains a tried and tested, predictable solution. Yet, the networks of today have radically evolved in recent years and created a multitude of new networking scenarios which necessitate new measures.
For example, not all that long ago managing and protecting an enterprise network was relatively straightforward. The boundaries were clearly defined. The equipment using that network were known quantities and the applications running over the system were in-house from fixed locations. The architecture was clear and immutable and managing through firewalls and anti-virus protection was the order of the day.
This dividing line has all but dissolved in recent times with the growth in mobile enabled laptops, phones, IOT devices and more. It makes for a much more dynamic network environment in which to deploy, manage and, crucially, control what’s going on.
This is not a network environment that makes nice with legacy WAN architectures such as MPLS. However SD-WAN has the capacity and flexibility to meet the new demands being faced by network managers and provide a pragmatic solution.
It’s the SD in SD-WAN that’s the compelling part of this. SD-WAN offers a way of managing a network across multiple locations… in software. It’s also a way to transition a business’s network from a hardware to a software focus and heralds a shift away from data centres towards cloud and SaaS applications.
Because SD-WAN is not dependent on hardware it can dynamically load-balance across multiple links to avoid backhauling issues that can crop up with MPLS solutions.
This added functionality creates choices. SD-WAN essentially facilitates new ways to improve network performance and connect employees across the planet while keeping data safe. It’s also more easily scaled as a business expands as the network architecture can grow with need.
Things to Consider with SD-WAN
Lower bandwidth costs — With the exponential rise in bandwidth-hogging high-definition real-time applications, relying on MPLS to scale can quickly prove untenable over the longer term. SD-WAN addresses this with much lower bandwidth cost implications. In many parts of the world broadband Internet performance is approaching parity with MPLS. This can cancel the need for costly MPLS network solutions.
Data Security — MPLS was designed in, arguably, more benign times, when concerns about ‘bad actors’ was much less of a consideration by network architects. This, however, means that there are potential flaws with the technology which the more modern solutions being implemented by SD-WAN architecture can address.
Upgradeability — Inherent in the approach to SD-WAN architecture is the ability to easily scale the network as new demand arises. Older technologies needed to be designed to a pre-defined architecture making after-the-fact changes to the topography far more challenging.
Transport Agnostic — SD-WAN can be indifferent to the network transport it utilises. It might be 4G for a mobile worker or xDSL for a small branch office where deploying a dedicated fixed line does not make financial sense.
Scalability — SD-WAN can move necessary bandwidth up or down in near real-time. It can also dynamically reallocate bandwidth to address new conditions or network applications. SD-WAN directly manages the allocation of bandwidth. This means businesses can ensure that critical applications get the bandwidth they want when they need it.
A Word of Caution
You might think that it’s all systems go for SD-WAN given the clear advantages it brings to the party in terms of price and flexibility. However, it is worth bearing in mind that, for all the pros, it does have potential cons. Perhaps the most obvious is its reliance on Internet Services within the architecture. This may have implications where such services are sharing bandwidth across multiple customers and adds a level of unpredictability.
Yet, it’s a cost to performance calculation which has only got easier to make as the underlying backbone of the public Internet continues to improve. That’s why SD-WAN is predicted to grow at over 40.4% annual compound growth rate between 2017 and 2022 according to IDC. [ source ]
If you haven’t considered how SD-WAN can complement your existing and future network plans, perhaps now is the time to look at what it can do for you.