Open and Modular is the Next Thing for SD-WAN

By Amir Zmora

Amir Zmora is the founder and CEO of flexiWAN. The opinions expressed in this guest blog post are his own.

SD-WAN is the new enterprise network. In the coming years all enterprises will move to Software Defined Networking. The question is not “IF” but rather “HOW”.

If you ask the incumbent large networking companies, the ”HOW” should be similar to the way it was done so far, simply because this serves the existing monopolistic business model of these vendors which is:

  • Coupling of SW & HW - even if they offer a SW only solution, the recommended and common way of purchasing is still coupled with HW
  • Large monolithic SW stack
  • All the right infrastructure for locking in the customer to a single vendor solution

In his blog post, Second Generation SD-WAN: How To Migrate, Tomas Hedqvist reviews the shift from this traditional model to a uCPE and VNF based model that takes away the HW lock-in and allows for more vendor selection flexibility.

This flexibility is still in the VNF level. In this blog post I want to talk about the next level of flexibility, the one that will allow service providers to really differentiate in the services they offer and reduce Total Cost of Ownership (TCO).

Open source building blocks that make an SD-WAN solution

SD-WAN products and services make use of open source building blocks. There is no sense in reinventing the wheel today and start from an empty clean white page when one comes to building his SD-WAN product.

In a presentation I gave at the SD-WAN Summit in September, I reviewed the different open source networking building blocks available today. The conclusions are:

  • There is a good open source coverage in the edge routing infrastructure and orchestration layers
  • There are gaps in the policy and management related layers both in the SD-WAN edge and management
  • It is not enough to simply glue a few open source components for building an SD-WAN product, there is still a lot of work required for building a real SD-WAN product

Note: Check out the blog post I wrote about it and download the presentation from there.

The state of the market today is that open source is part of the SD-WAN solutions but users don’t really benefit from this fact. flexiWAN changed this by offering a complete open source SD-WAN solution.

In the POC of Enea, flexiWAN and Intel, we have demonstrated how a secure SD-WAN solution can be built from open source solutions.

The shift to a modular SD-WAN deployment

Traditionally, SD-WAN comprises an edge device (SW only or HW+SW) and a central management that manages these edge devices. The lack of a finer grain horizontal separation is the foundation for the vendor lock-in present in current SD-WAN solutions.

Breaking an SD-WAN solution to horizontal layers allows for creating a more flexible and modular architecture.

Figure 1: The horizontal layers required for a modular SD-WAN

In the image above we see the 2 main layers of such an architecture. We will look at this in greater detail later in this blog post.

The networking infrastructure layer is what makes connectivity and central management of the network happen. It allows for the creation of secure tunnels between the branches themselves and between them and the cloud in various topologies (full mesh, hub and spoke and and combination of these) and manage it from one central location. This also requires the implementation of routing protocols and managing the complete lifecycle of the solution including SW upgrades, availability and health checks.

The layer on top is where flexibility and modularity should come in place. In this layer we have the various networking applications that implement the more advanced networking technologies.

flexiWAN allows for reduced TCO through a modular open architecture

Based on the horizontal layers described above we can create an application infrastructure that will span edge and central management.

Figure 2: The flexiWAN SD-WAN architecture

The image above provides a high level view of the flexiWAN SD-WAN architecture. In this architecture, we can see the application infrastructure that rides on top of the routing infrastructure. This layer is what allows for integrating 3rd party networking applications into the router and management as well as managing, synchronizing and provisioning them.

In conclusion

Applying modular and open source concepts to SD-WAN will yield the following benefits:

  • TCO reduction of 50% to 90% due to
    • Modular software stack – use what you need versus the entire bloated software stack that in many cases requires 4 cores and 8G minimum
    • Success based licensing – Freemium based model with the base open source for free and a nominal fee for additional features that add value
    • Community – Open source community for development and support
  • Removing vendor lock-in – Open architecture & open source allows to pick and choose the best of breed components instead of a one size fits all solution
  • Future proof – Integration of future technologies (e.g. AI, handling encrypted traffic, move towards zero trust networking)
  • Differentiation - Service providers can offer differentiated services and have better control over their SD-WAN service