What is SD-WAN Architecture and its Different Types?

Introduction

Wide Area Networking has grown and developed in a very spectacular manner. From MPLS networks up to SD-WAN (Software Defined WAN), the necessity of having a solution that is different, much more agile, and flexible, but above all, less expensive has fostered the evolution of this sector. However, WANs’ role in today’s digital environment cannot be overestimated as they ensure the connection to distant locations, communicate with customers and use cloud-based solutions. Still, WAN has many issues so, SD-WAN was developed as an alternative to WAN.

In this blog, we will mainly discuss SD-WAN architecture and design, its components, its types, different ways to deploy SD-WAN architecture, form factors, and some of the benefits it offers.

Contrary to SD-WAN being seen as some new technology, we consider it as a new architectural approach to managing the WAN in enterprises. It implements the fundamentals of software-defined networking to manage and orchestrate the network processes that, in turn, allow organizations to address their key goals of network efficiency, protection, and trouble-free operation. To gain a deeper understanding of SD-WAN, you can take Cisco SD-WAN Training.

Before getting into SD-WAN architecture and design, let us first understand what SD-WAN architecture really is.

What is SD-WAN Architecture?

SD-WAN architecture denotes a new form of connectivity for the WAN where the software is used to hide the physical infrastructure layer to make it fully manageable from one central point. It logically divides the control plane from the data plane for a dynamic routing flow and is capable of custom policies.

SD-WAN architecture is built around the principle of the capability to steer data traffic over one or more transport technologies with references to policy and application. This enables organizations to achieve a combination of low-cost and high-performance networks that meet their business requirements while at the same time, being secure.

Now that you have a basic understanding of SD-WAN Architecture, let us now understand the different SD-WAN components.

SD-WAN Components

To understand the SD-WAN architecture, it is essential to familiarize ourselves with the three primary components that make up this dynamic network solution:

SD-WAN Edge

The SD-WAN Edge is also called the SD-WAN device or the edge router, and it is the primary point at which the local network connects to the WAN. This is usually deployed at the customer site for centralized facilities, branch offices, or a far-end site and is accountable for directions of information exchange between the local network and SD-WAN fabric. SD-WAN edges can be physical appliances, virtual machines, and or cloud services.

The SD-WAN Edge is equipped with advanced capabilities, including:

• Multi-link connectivity: The capability to be accessible to various transport technologies like Broadband, MPLS, and Cellular in one instance.
• Dynamic path selection: The intelligence to determine the best mode and path suitable for transmitting data as per the application needs, condition of the network, and costs involved.
• Intelligent traffic routing: The ability to select and direct traffic in accordance with the policies that are set up at the application level to guarantee high-quality traffic handling and bandwidth utilization.
• Integrated security: The inclusion of security measures such as firewalls, VPNs, and other enhanced security measures to protect the network.

SD-WAN Orchestrator

The SD-WAN orchestrator is the management and operational layer of the overall SD-WAN structure. It works as the controller of the system since it oversees and coordinates the control over the whole SD-WAN fabric and the SD-WAN Edge devices.

The key functionalities of the SD-WAN Orchestrator include:

• Centralized management: The centralized point of management of the SD-WAN environment or the ability to design, manage, and control the network from a single web portal.
• Policy creation and enforcement: The ability to set policies at the application level, security policies, and QoS policies, as well as enforce them universally across the network fabric, is called SD-WAN.
• Visibility and analytics: The ability to offer real-time visibility in the overall network status, application usage, and performance to make necessary adjustments.
• Automated provisioning: The optimization of the deployment process through the automation of the configuration and deployment of the SD-WAN Edge devices at various sites.

SD-WAN Controller

The SD-WAN Controller is the element that performs routing and traffic management in the consistent SD-WAN architecture. It cooperates with the SD-WAN Edge devices to decide in real-time about the best path for data transfer according to the policies and conditions that are set up.

The key functions of the SD-WAN Controller include:

• Dynamic path selection: This feature enables the device to automatically detect the state of the network at any time, pick the best path for each application or flow, and guarantee maximum efficiency and reliability of the connection.
• Load balancing: The ability to transmit the network traffic over many links to effectively use available bandwidth without creating a bottleneck.
• Application-aware routing: The intelligence to force, filter, and monitor application-level policy so that emergency applications will be given an adequate response and efficiency.
• Seamless failover: This involves the provision of automatic failover mechanisms and other functionalities that would ensure that the network connection does not fail due to a failed link or a network device.

Below, we have discussed different types of SD-WAN Architecture.

Different Types of SD-WAN Architecture

As the SD-WAN market has evolved, several distinct architectural models have emerged to cater to the diverse needs of organizations. Understanding these different types of SD-WAN architecture can help businesses choose the solution that best aligns with their specific requirements.

On-Premise SD-WAN

Within the context of on-premise SD-WAN, the edges, orchestrator, and controller are housed within the organization’s own infrastructure and data center. Compared to the other two approaches, this approach offers better control and fine-tuning of the network because organizations own and manage the entire SD-WAN solution.

Cloud-Enabled SD-WAN

Managed SD-WAN supplement cloud-featured SD-WAN, where the best practices are implemented by having the SD-WAN Orchestrator and Controller maintained as cloud solutions on a cloud platform by the vendor or third-party provider. The SD-WAN Edge appliances are still at the customer location, but the management and control planes reside in the cloud.

Cloud-Enabled plus Backbone SD-WAN

The next in the line is the Cloud-Enabled plus Backbone SD-WAN which is an enhancement of the Cloud-Enabled model by the inclusion of a backbone network either by the SD-WAN vendor or a third-party service provider. This backbone network acts as the primary transport network for SD-WAN traffic and is quite reliable as well as faster than public internet transport.

Let us move on to another section where we will discuss SD-WAN architecture deployment. 

Types of SD-WAN Architecture Deployment

There are different types of SD-WAN-related deployment models, and based on the organization’s requirements, a proper selection procedure is necessary to achieve the best outcomes. Three common SD-WAN deployment models are:

DIY (Do-It-Yourself)

In this model, the organization is wholly responsible for the implementation as well as the ongoing management of the SD-WAN architecture. While it is possible, it takes the company’s resources, skills, and time to build an exclusive app with the highest adaptation and regularity control.

Fully Managed

In this model, they are completely contracted out, meaning that the organization shall only purchase SD-WAN from the third party. At the same time, the Provider shall be responsible for its installation, configuration, and maintenance. The primary advantage of this approach is that it relieves the organization from requiring the necessary expertise and internal/local resources; however, this method is rather costly and often does not allow for much variation.

Hybrid or Co-managed

This model is also considered to be a mixture of the DIY and fully managed deployment types. The organization may decide to manage and control some of the features of the SD-WAN while outsourcing the others to a third-party provider. This is preferred due to the relative control it avails while minimizing costs.

For better understanding, we have explained the different form factors below.

SD-WAN Form Factors

SD-WAN solutions can be provided in different form factors which makes it quite flexible for organizations. These form factors include:

Physical Appliance

The physical appliance form factor concerns the use of physical end-point appliances, called SD-WAN Edge devices, at the customer’s site. They are usually built for the requirements of SD-WAN and have much-enhanced networking and security features.

Virtual

The virtual form factor of SD-WAN is also specified by physically embedding software-based SD-WAN Edge devices, which can be deployed on application instances on server or cloud nodes. The advantage of this approach is the flexibility and scalability of virtual SD-WAN Edge equipment, which is easy to provision and manage.

Cloud

The cloud form factor of SD-WAN concerns the integration of the entire SD-WAN structure up to the Edge devices, Orchestrator, and Controller in the cloud. This model builds on the cloud-centricity of the core services to bestow the SD-WAN provider the features such as scalability, flexibility besides cost-effectiveness to be interesting to organizations that are aligning with cloud-first strategies.

Benefits of SD-WAN Architecture

The adoption of SD-WAN architecture has brought about numerous benefits for organizations, including:

• Cost Savings: SD-WAN architecture has the potential to cut WAN expenses down by making use of broadband and 4G/LTE connection.
• Improved Application Performance: On the applicational level, SD-WAN architecture can positively impact the application performance by choosing the available path for traffic forwarding.
• Increased Agility: SD-WAN architecture helps organizations to deploy and manage WAN services rapidly: the time required for new locations is minutes against weeks.
• Enhanced Security: Executing WAN route implementation through SD-WAN architecture includes security protocols such as encryption, firewall, and intrusion.
• Simplified WAN Management: This method enables the WAN to be controlled in a centralized manner, thereby decreasing operational complexities.

Frequently Asked Questions

Q1 – What are the three types of SD-WAN architecture?

There are three types of SD-WAN architecture:

• On-premises
• Cloud-based
• Hybrid

Q2 – What are the layers of SD-WAN architecture?

The SD-WAN architecture has three layers:

• Application Layer: Identifies and prioritizes apps.
• Controller Layer: Manages and directs network traffic.
• Network Layer: Connects and transports data across WAN.

Q3 – What is SD-WAN and how does it work?

SD-WAN is a networking technology that securely and intelligently routes network traffic between branch sites, the cloud, and headquarters, ensuring reliability and application performance by prioritizing business-critical data.

Q4 – What is Cisco SD-WAN architecture?

Cisco SD-WAN architecture is a software-defined networking approach for building and managing secure, cloud-enabled wide-area networks.

Conclusion

SD-WAN, as a concept, is a software-defined wide area network that is more flexible, economical, and secure than other traditional WAN architectures. SD-WAN Architecture is continually changing and is now a critical solution for companies that need to upgrade their networks. Despite the fact that there is a wide range of SD-WAN architectures and choice of deployment models, one can easily select the most suitable solution.