SD-WAN Architecture

There are dozens of companies offering SD-WAN solutions. Broadly, these solutions fall into 3 different types of architectures – Carrier SD-WAN, Overlay SD-WAN and Cloud-First WAN

Carrier SD-WAN

Carrier managed SD-WAN networks are built using equipment sourced from multiple vendors, with each vendor providing a proprietary configuration and monitoring solution, hence making a unified view of the network hard to achieve. The situation is further complicated by the fact that carriers tend to operate within their national boundaries, thus requiring complex inter-carrier agreements for international connectivity. Some challenges associated with the carrier SD-WAN approach include:

Lack of unified configuration and monitoring makes providing agile, on-demand services difficult. Inter-carrier agreements on international routes make them expensive and complex. Many carriers provide no choice to their customers for first-mile or last-mile connectivity, often forcing them into expensive contracts.


With so many different types of equipment and multiple service providers, ensuring consistent SLAs and service quality can be challenging. Carriers and telcos are unable to deliver on the cloud-first experiences demanded by business today. This is reflected in middling to low Net Promotor Scores (NPS) for carrier MPLS services.


However, there are some advantages in working with a carrier or Managed Service Provider (MSP) in that some have global reach, last-mile assets, and a history of delivering managed services. An organization that uses a given carrier for one service — voice, for example — will be more apt to use this same carrier for others.


SD-WAN Edge Overlay

The elementary approach to SD-WAN is to deploy it as an edge overlay solution. In this configuration, the overlay solution provides some benefits over the legacy MPLS network because it leverages local internet connectivity at branch locations. The SD-WAN CPE provides the necessary functionality to route and distribute traffic between the MPLS network, the Internet, and any other available connectivity. Depending on the network quality, application traffic can be routed via the MPLS network or the public Internet, neither of which is a perfect solution for application performance in the cloud era. Some challenges associated with the SD-WAN edge overlay approach include:

  • When routed over the Internet, application traffic that requires predictable performance is subject to loss and latency issues associated with the Internet.
  • This method is not really designed for global deployments where predictable application performance is required.
  • WAN optimization is an add-on function to MPLS, making the overall solution more expensive.
  • This method relies on the underlying Layer 3 network for quality of service (QoS) convergence and thus can’t offer the rock-solid SLAs of a Layer 2 network.
SD-WAN edge overlay architecture
Cloud-first WAN architecture

Cloud-First WAN

A cloud-first WAN (dummies book) provides a better approach to an SD-WAN that supports enterprise digital transformation with flexibility, speed, and simplicity in the WAN architecture delivered “as a service.” Learn about the different approaches to WAN and SD-WAN deployments, the pros and cons of the different models, and the advantages of a managed, cloud-first WAN experience.

Additional Resources

SD-WAN Architectures Explained

A comparison of different SD-WAN architectures including Aryaka, Cisco, VMware, AT&T, and others.

What IT Leaders Should Know About the SD-WAN Market

Read this white paper to understand industry analysts’ predictions about the growth of the SD-WAN market and why they matter to IT leaders preparing for digital transformation initiatives.

Aryaka Global SD-WAN:
Company Brief

Aryaka’s global SD-WAN provides fast, reliable, secure, and scalable connectivity, and application acceleration to globally distributed enterprises.

Additional Resources

  • SD-WAN Architectures Explained

    A comparison of different SD-WAN architectures including Aryaka, Cisco, VMware, AT&T, and others.

  • What IT Leaders Should Know About the SD-WAN Market

    Read this white paper to understand industry analysts’ predictions about the growth of the SD-WAN market and why they matter to IT leaders preparing for digital transformation initiatives.

  • Aryaka Global SD-WAN:
    Company Brief

    Aryaka’s global SD-WAN provides fast, reliable, secure, and scalable connectivity, and application acceleration to globally distributed enterprises.

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