SD-WAN: Proof of Concept

The first step to thoroughly understand the technology, opportunities and challenges ahead

SD-WAN is a game changer for the traditional enterprise networks and its implementation is not a straightforward process, whereby, a proof of concept is a mandatory step towards a future proof network, which needs to be carefully designed and evaluated prior to a global rollout.

Don’t under estimate starting small

Once identified SD-WAN as the target solution for the future enterprise network environment since it fulfils both technical and business requirements, it is crucial to thoroughly evaluate the full potential of the technology is a reduced but representative scope. As all revolutionary technologies, is highly recommended to verify SD-WAN through the execution of a Proof of Concept (PoC) in order to validate its full potential, compare multiple vendor solutions and reduce the migration risk prior to an extensive and global roll-out that might require a high effort and investment.

In order to properly run a successful PoC, it is highly recommended to follow a three stage approach as per described below.

  • Preparation: Identify Goals | Define Scope | Setup Test Platform | Set the baseline
  • Deployment: Implement Underlay | Design Overlay | Migrate & Hypercare
  • Reporting: Benchmark | Lessons Learned


The main idea behind the execution of a PoC is to validate the technology and how that technology matches the technical and business requirements previously identified in the network strategy definition. Therefore, it is critical to crystalize the aims and goals for this stage in order to manage expectations from the internal stakeholders and define a clear scope for the PoC.
Once identified the main goals, they should be translated into a technology scope, where the following items should be taken as part of the critical preparation path:

  • Target locations: identify enterprise locations (remote branches or central data-centres) as suitable candidates according to their site topology, connectivity technology, geographical location, link capacity, and business criticality.
  • Applications and services: a subset of network services and applications must be depicted according to its potential of improvement and always taking into consideration the current performance, since it would be important to select those who have not been not performing accordingly to user and administrator expectations due to network constraints.
  • Success criteria: the success of a PoC must be clearly measure according to Key Performance Indicators (KPIs) and their benchmark against past metrics, which might come from technical (e.g. latency reduction, capacity increase) or business (e.g. cost reduction, user satisfaction) departments.
  • Test cases: specification of granular test cases to properly benchmark the network service performance before and after the SD-WAN technology rollout, which could vary from cost benchmark up to cloud application performance, depending on the target goals defined for the PoC.

Although important, the theoretical scope definition is not enough to properly prepare a deployment of a PoC. It is important to design and implement a suitable test platform to run the desired test cases. Here, multiple options can be considered such as in-house testbeds (e.g. multiple virtual machines across the customer environment acting as end-users) or outsourced testing platforms (e.g. probing hardware to capture and analyse network traffic). Their selection will vary according to customer scope and budget.

As a final step of the preparation stage, a baseline of performance must be built in order to allow the benchmark of the SD-WAN use cases results against the current network status.


Now is time to jump into the actual deployment of the new network concept, which should cover underlay transport as well as SD-WAN overlay design and rollout throughout the pre-defined target locations.

The first step should be to prepare the underlay connectivity to fulfil the envisioned use cases such as usage of cheaper connectivity forms, quicker cloud connectivity or local access to public internet services. Usually those use cases are supported through the implementation of a hybrid WAN concept where multiple connectivity transports are used in parallel, including the legacy forms as MPLS or Internet, and newly ones as mobile (e.g. 4G or 5G). This is usually supported by the multiple Communications Service Providers (CSP) provides connectivity services to the client in the target locations, being mainly a de-centralized process.

After ensuring a proper underlay, the next step should be the design and implementation of the overlay concept, which should translate the business goals and requirements into network specifications and policies. Therefore, the network administrators must focus on the stratification of business intent overlay such as real-time voice/video, critical application or bulk data, being this classification highly dependent on the customer needs and scope.

Finally, the migration could take place as soon as both underlay and overlay are properly designed and all the necessary preparation activities (e.g. hardware ordering, low-level design, migration run-book, acceptance tests) are fulfilled. In the case of PoC deployments in a production environment, a hypercare phase should be always considered to ensure a closer monitoring a proper early-life support, along with a solution stabilization and fine-tuning.


The main goal of a PoC is to benchmark the network service performance against a situation without SD-WAN. Therefore, and once the solution is stabilized, new data must be acquired from similar test cases as executed during the preparation phase where the performance baseline was set.

Within the reporting phase, the KPIs should be analysed for each target application or service when running the test cases, to verify if network policies and services prioritisation are being applied. Raw data should be handled to create performance reports and benchmark the results with the market reference values and expected performance from the preparation phase, to make sure the solution is running on is full potential and bringing the expected business outcome.

Ultimately, the PoC has the goal to identify lessons learned and mitigation actions to reduce the risks on the global rollout project, and ensure the deployment of the optimum SD-WAN solution is the smoothest way possible.

One step closer to the big goal

Although the complexity and duration of the PoC should be carefully analysed depending on the size and complexity of the network, a stepped SD-WAN implementation is highly recommended to reduce migration risks and do not disturb the network performance. Following this approach, the client will be one-step closer to the ultimate goal of having a performing, cost efficient and future proof enterprise network to support the business demand and growth.

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