SD-WAN is a software-based approach to managing a WAN, and there are a number of reasons why your customers should consider its adoption. Once the decision to move forward with SD-WAN is made, however, it’s important to properly vet solutions and vendors. Continue reading
We are all learning the acronym SD-WAN, but to layer 2 and 3 OSI model aficionados, it can be hard to accept how an upstart layer 7 software application can potentially replace a stalwart layer 3 technology like multiprotocol label switching (MPLS). Which begs the question: Is SD-WAN a contender, or just a pretender in the future generation of networks?
MPLS: The Incumbent
When MPLS was introduced, medium and large businesses rapidly adopted the technology. Deploying an MPLS network to connect offices together provides users with the ability to have a predictable, secure, and high preforming environment. This is done by bringing all your data through a single provider and allowing them to prioritize your traffic at layer 2 or layer 3 using QoS.
Providers can provide QoS through specifically designed networks with logical separation using labels to identify traffic, VRFs, and VRF tags to separate the customer traffic. They then allow customers to apply QoS tags to traffic types to reach higher levels of availability.
Let’s look at how this works in more detail, as this is the meat of what customers care about.
When designing MPLS, it is important to determine how you want to provide this QoS. The first thing to do is identify traffic of similar kind and then a degree of excellence. In a typical deployment, 4 quality queues are seen as defined below:
- Real-time traffic – This is typically voice, video, and/or VDI.
- Business Critical – This includes applications required for a company to do business. Examples might be an EMR for a medical company or credit card transactions for a retail company.
- Business Important – This might be an intranet, active directory, email, or other application that is not sensitive to jitter, latency, or retransmits.
- General Traffic – This queue includes all other traffic.
Once customer traffic has been identified and tagged, the degree of excellence of those tagging/groupings must be defined. Most carriers offer a different service level for each queue and different bandwidth guaranteed to each traffic type across the entire MPLS network. As companies continued to converge, however, holes in this design were found. This brought forth the creation of SD-WAN.
SD-WAN: The Contender
Instead of using QoS (layer 2 or layer 3), SD-WAN uses software definitions. With MPLS, you must either use only a source or destination IP address or port. That would be the same as saying you can only relieve traffic congestion from where you started, where you are going, or based on the type of car you have. This would not be very helpful in a major situation where most traffic is destined for the same general area. But what if you could also consider important factors, like ensuring doctors and first responders were never caught in traffic? That one additional factor could change the landscape in most cities and potentially save lives. In terms of the company network, that would be the same as having a real-time queue.
This is what SD-WAN does to QoS. Video traffic can be prioritized to YouTube over Netflix, for example, or Office 365 email over personal Gmail accounts.
Not Beholden to a Single Carrier
With MPLS, the entire environment must be controlled by a single provider. This means that you cannot choose the most cost effective solutions for each location, which doesn’t work for customers with large geographical environments. SD-WAN allows the most cost effective solution per location be chosen.
Significant Resilience Improvements
With MPLS, providing redundancy is very difficult as MPLS routing uses private IP. For the secondary connection, most customers choose to use a VPN over an internet connection. They then need a device that is intelligent enough to build the VPN and handle routing between the two solutions. Even then, routing with just layer 3 protocols doesn’t allow different levels of resilience or performance increases. Typically, customers settle on having the VPN be active/inactive (or hot/cold), meaning that the other connection is ONLY used when there is a total failure of the MPLS.
With SD-WAN, the world of high-performing resilient networks comes with a lot of options. You can define and build it so that both connections are used, called active/active or hot/hot. You can prioritize based on application type; for example, real-time traffic can be forced down a high-quality connection with SLAs associated with it, and general web traffic can be sent down a more cost effective connection. Other business critical or important traffic can be bundled to go out both connections, maximizing total bandwidth.
The flexibility and design options increase exponentially with the introduction of SD-WAN. MPLS still has its place and will for years to come, but for many customers SD-WAN provides a great alternative that may help them meet their internal goals.
SD-WAN is getting a great deal of air play in the industry right now, promising to solve every network challenge that embattled network architects and operators are experiencing today from insatiable bandwidth requirements and costs through simple network resiliency and management. But what is marketing fluff, and what is real? What are the real drivers behind this latest “transformational” technology, and what problems does it really solve?
More Affordable Network Needed
With increasing workloads and performance requirements, especially with the proliferation of cloud-based applications, the need for predictable, high-speed, secure, and diversified networks is escalating. It simply isn’t always financially feasible to deploy diverse MPLS links to multiple distributed offices.
SD-WAN enables companies to take advantage of less expensive internet access rather than managed private networks while still getting the benefit of the types of capabilities provided by an MPLS network. In many areas, tier one direct internet access actually (and maybe surprisingly) provides lower latency, lower jitter, and lower packet loss than its expensive MPLS counterpart, so companies with a large number of distributed offices can expect to see real cost benefits with an SD-WAN network versus a traditional MPLS network.
Simpler and Faster Deployment
MPLS circuits can take months to provision and turn up. The underlying internet access types that SD-WAN can take advantage of can be faster and easier to deploy. However, don’t be misled by the myth that SD-WAN is simple to deploy. There is still a substantial amount of planning and configuration to be done. Beware of the “plug and play” misconception and investigate how each solution is deployed, as they are all different.
Not all SD-WAN solutions are as easy to manage as you might think, and not all management portals provide the same functionality. Whether you are looking at a service provider-managed solution, your own “book end” managed solution, or are using a dedicated SD-WAN network provider, look carefully at what priorities you can set and what monitoring you can do. Are these to device level (MAC address) or location level (essentially just network aggregation and optimization solutions)?
And, most importantly, don’t forget about how software updates are applied and managed and how template policies are set and administered — the very things you would think about when managing routers in your network.
There are claims made that MPLS is more secure than SD-WAN. In reality, an MPLS network is only as secure as the accuracy of the MPLS provider’s switching. The use of IPSec connectivity and additional service chaining in an SD-WAN environment should be more than sufficient to address most security concerns.
You can’t simply turn to Gartner’s magic quadrant and pick a leader. The industry is too young, with many new market entrants. Whatever deployment method you are going to use, be sure to check the underlying equipment vendor’s track record. Financial stability and investors are important. Ask for references and don’t forget to look under the hood at the vendor roadmap to understand future solution enhancements such as scalability.
MicroCorp was a pioneer when MPLS came along. We have over 30 years of experience delivering complex network solutions and helping businesses discover the right technology for their operations. Contact us to learn more about a partnership in adding SD-WAN and related technologies to your portfolio of solutions.