Seven steps to SD-WAN deployment

The benefits of software-defined WANs are appealing to many enterprises, but the deployment process can seem daunting.

Enterprises can use this seven-step process as a guide for a successful SD-WAN deployment.

Step 1. Collect requirements

Gathering requirements is always the first step in deploying an SD-WAN architecture.

Enterprises often cite cost reduction through MPLS WAN as a key requirement, but SD-WAN does not always provide significant cost benefits. Instead, network teams should seek to improve network resiliency to avoid outages, or strengthen network security to ensure a workforce that works anywhere, anytime.

Other benefits include a more agile business due to the centralization or reduction of operations and maintenance tasks, freeing up staff to work on strategic initiatives.

Step 2. Identify the site configuration file

Use the functional requirements specification to determine connectivity requirements, application traffic, quality of service (QoS), quality of experience, bandwidth, and security. Then, identify a small number of different site types in the network. Minimizing the number of different site types increases consistency across the network, leading to greater automation, faster troubleshooting, and reduced configuration complexity.

Teams can categorize sites into the following categories:

• Offices with video conferencing and SaaS connectivity;
• Manufacturing plants;
• storehouse;
• Engineering design facilities or medical housing centers, which typically have large files, high bandwidth, and custom applications;
• Enterprise data centers hosting proprietary applications.

The profile for each site determines the functional requirements for factors such as link bandwidth, failover circuits, QoS, security, and monitoring.

Step 3. Choose a Proof of Concept Site

Identify the Proof of Concept (POC) sites. Select some of the most important site types for the POC. Once identified, the next step is to determine the circuit characteristics of the site to order the appropriate test circuits. The lead time for procuring circuits is usually long, so the team should arrange circuit orders for the site as soon as they know which links to order.

Thoroughly evaluate the carrier architecture, as some providers severely oversubscribe their network infrastructure, resulting in higher levels of packet loss. Note that even small levels of packet loss can cause significant degradation in application performance. Include packet loss measurements and independent measurement mechanisms in your service level agreement with the carrier.

Step 4. Evaluate the product

Start evaluating potential products, reference industry resources on potential vendors, and begin to consolidate selection criteria. The market is changing rapidly, with new product features being released regularly. Competition is intense, but features from different vendors are comparable with some proprietary variations. Features such as Secure Access Service Edge are becoming commonplace.

Keep in mind that the protocols used for SD-WAN are proprietary and do not support interoperability between products from different vendors.

Step 5. Compare DIY vs. managed services

Next, determine the type of offering available: DIY, co-managed with a managed service provider, or fully outsourced to an MSP. The choice depends on the resources the team can gather for evaluation and deployment. For example, a global enterprise may find it more effective to choose an MSP that already has established relationships with ISPs abroad.

Finding an MSP that is familiar with providing SD-WAN can be beneficial because it can leverage its experienced people, processes, and technology. These resources can simplify the evaluation and SD-WAN deployment, making it worthwhile.

Step 6. Test the proof of concept

Start doing hands-on evaluations of your POCs in the lab. This step can be done while waiting for circuits and can cover as many products as possible, although the network team should probably limit it to the top two or three candidates. Be sure to evaluate performance using traffic generators and monitoring capabilities.

Do the policy mechanisms provide the required functionality? How easy is zero touch provisioning (ZTP) to deploy? Do the traffic handling policies apply to the traffic mix? How do SD-WAN interfaces work for unconverted sites? What visibility does the monitoring system provide? Are security measures effective? Create failure scenarios and evaluate network management alerts and troubleshooting mechanisms.

It may be tempting to create a partial or sample strategy for testing purposes, but this may end up costing more than it is worth. It is better to focus on the thought process of identifying all elements of a production strategy so that the team understands the product, its limitations, capabilities, and whether it achieves its goals.

It is possible to use the product in this step without impacting production applications, so be as thorough as possible. Leverage the product’s automation systems to run evaluation tests. Also, if possible, create the tests to use on a production network. This is where an experienced SD-WAN MSP can come into play. The result of this step should be the identification of potential vendors.

Step 7. Decide on the SD-WAN model

Determine the appropriate deployment model. The vendor will either offer a preferred model or give the customer a choice. Will hardware be needed at each site, or will a virtual deployment requiring a VM host be used? Can ZTP be shipped directly to each site, or will it need to be staged somewhere? How can the team validate the circuit before putting it into production?

Use deployment models to scale your POC from the lab to low-risk production sites.

If successful, then continue to deploy to other POC sites. This step validates the implementation and deployment model in the production environment. It should provide few surprises other than perhaps finding one or two forgotten applications. Include at least one of each type of critical production site in this step to validate that the product meets the most stringent requirements.

Make your final choice

This concludes the assessment process. These steps may feel daunting, but the complete approach will result in a smoother transition to a production deployment.