The last few years there has been a lot of talk about SD-WAN and now as we reach the end of 2017, products have become mature enough that a lot of enterprises are actually deploying this technology. The market is starting to consolidate because there are too many vendors out there currently, case in point Cisco acquiring Viptela and now VMWare buying Velocloud. Some of the SD-WAN vendors have chosen to focus on carriers and MSPs, which is a good market for them. From a customer point of view, does it make sense to buy SD-WAN from an ISP?
To answer this question we must think about what the main drivers are to go SD-WAN (from my point of view).
Cost – The main reason for SD-WAN is to cut your WAN costs. WAN costs are a significant part of the overall IT cost.
Ownership of WAN – Enterprises want to own the WAN to be able to move at a more rapid pace.
Transport agnostic – The purpose of SD-WAN is to be transport agnostic, meaning that you can build your WAN over whatever type of transport is available that fulfills your needs and fits the cost profile.
Intelligent routing – Traditional routing protocols don’t easily allow for routing based on the performance of a circuit, such as latency, jitter and packet loss.
Now let’s think through these four main drivers and how buying SD-WAN from an ISP would fit into this model.
Cost – When buying SD-WAN from an ISP you don’t have complete freedom in building your WAN over any ISP. The largest cost of the WAN is paying for the circuits. You are giving up your ability to put ISPs against each other and negotiate the best deal available. To sum things up, you are putting money on the table.
Ownership of WAN – Buying from an ISP means you don’t own the WAN. How fast can they deploy a new office? Do you get any access to the equipment? How much time do they need to implement a change? Those are major concerns if you are outsourcing your WAN.
Transport agnostic – If you buy from an ISP you don’t have freedom to choose whatever ISP you want to and that is available in a certain region. This makes things more complicated and expensive.
Intelligent routing – You do get intelligent routing but only on the transports available from the ISP you are buying the service from.
There are obvious downsides to buying the service from an ISP. Here are some more things to consider:
- Complexity – A good SD-WAN product should be easy enough to operate for an enterprise, not having to rely on an external party. Considering how much money can be saved on your WAN, having some expertise on staff can make sense.
- Agility – How fast can the ISP react to your requests? How important is your business to the ISP?
- Competence – ISPs don’t generally attract the best talent because there are only a few really interesting roles available and the bulk of roles revolve around answering customer calls and keeping the lights on.
- The blame game – Sure, you have a single choke to throat but will the ISP take full ownership for resolving issues or will they blame the SD-WAN vendor when things go wrong?
- Fate sharing – What happens when your ISP has a major outage? What good does your SD-WAN do then if there are no circuits that are up or performing well enough to take your traffic? You may think you are safe because you are buying MPLS but if the ISP is getting DDoSed over the internet, think again.
There are pros and cons to all business models but giving up ownership and hence cost of your WAN in the modern era of networking is very risky. Consider all of the things I have brought up in this post and make sure you have a plan on how to approach them if you decide to outsource your WAN. If you are thinking that IT is not your core business, you are likely wrong but that’s a topic for another post. Good luck in your SD-WAN deployments and remember that there are tradeoffs in all designs, if you haven’t found them you haven’t looked hard enough.