Why is SD-WAN Critical to Your IT Strategy

Justin Rice

Part 1 – Legacy WANs are Complex.
 
Historically, WANs (Wide Area Networks) are complex. In a distributed enterprise with multiple locations, you had to invest in dedicated MPLS circuits to connect all sites together.  Even then, you weren’t able to get the bandwidth necessary to truly meet the needs of your business.  For example, you’d have to purchase a T1 at all of your branch locations from your service provider for the MPLS connectivity.  That provider would then place a router at the edge of your network, which you do not have access to, route all traffic back to a head end.
 
In this type of deployment, you had one primary goal:  Give me a private, dedicated circuit to connect to my head end that has consistent quality and reliability to ensure by business does not suffer. 
 
MPLS was a great solution at the time because the transition to the cloud really hadn’t started.  All of your compute (servers, etc), was still on premise, as were your applications and storage.  You HAD to connect back to a head end, so what better way than MPLS?
 
To meet this goal, you HAD to invest in this technology.  First off, lower cost bandwidth was nowhere near as reliable and you certainly couldn’t get quantity of bandwidth that is readily available today.  A simple cost/benefit analysis would prove that this just wasn’t an option. 
 
The downside of the MPLS investment is two-fold:  1. Lack of bandwidth speed, and not easily scalable.  2. Lack of visibility.  Sure, you’re getting better quality and reliability – no argument there; however, you can’t truly see what’s happening across the MPLS network, you can’t guarantee control of your applications, and you have no real mechanism to hold your MPLS provider accountable if they are not meeting their SLA.
 
Part 2 – Movement to the Cloud.
 
As the 2010s came around, there has been a historic shift to “Cloud Services”.  It’s almost cliché to a point, but it’s true.  There is such a large shift in cloud investments, that keeping services on premise is becoming a rarity.  For example, Amazon Web Services (AWS) and Microsoft Azure are making on premise compute and data centers essentially obsolete.  They make it so easy to spin up and migrate data centers to the cloud  that businesses are able to become more nimble than ever before.  The same rings true for phone systems.  You used to have to invest in a large phone system that would sit in a telecom closet somewhere in your facility.  If your building lost power, you were done.  Now, if you buy an on premise phone system you are in the minority.  Cloud Phone Systems give you so much more flexibility and features than an on-premise ever would. 
 
Those two are the low hanging fruit, but let’s not forget about Software-as-a-Service.  The days of keeping local servers for applications such as email, customer relationship management, billing, etc. are long gone.  You can now move almost any application to the cloud to give you much better flexibility, quality, and reliability than ever before  The list goes on and on: Storage, Security, are just a couple of more examples.  
 
This movement to the cloud has two HUGE implications if a business is still running on a legacy WAN.  1. Not enough bandwidth to support the demand of cloud applications.  2. Can’t guarantee quality and reliability to cloud-hosted applications outside of your existing WAN.
 
Part 3 – SD-WAN, Another Cloud Service
 
I mentioned in the last paragraph about all of the services moving to the cloud.  Why does the network have to be any different?  It doesn’t.  This is where SD-WAN comes in.  SD-WAN, by Industry Terms is:
 
The software-defined wide area network (SD-WAN) is a specific application of software-defined networking (SDN) technology applied to WAN connections, which are used to connect enterprise networks – including branch offices and data centers – over large geographic distances.
 
In the MPLS days, as you are designing the network, you talk in terms of “What kind of bandwidth do I need at the branch location to connect back into my head end”, but there isn’t really a lot of talk around business outcomesThat conversation changes with SD-WAN, where we start talking about Outcome-Based Networking.
 
When we talk about Outcome Based Networking with our clients, we start asking about what applications are critical to your business in order for you to be successful.  Thus, what outcomes do you need from your WAN to make you succeed?
 
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