Software-Defined Wide Area Network (SD-WAN)

What is SD-WAN?

Software-Defined Wide Area Networks (SD-WAN) exemplify the innovative capabilities of Software-Defined Networking (SDN) technologies, marking a paradigm shift in creating cloud-optimized networks. By integrating a layer of intelligence, SD-WAN transcends traditional network architectures, offering unmatched agility, flexibility, cost-efficiency, and performance: qualities essential for modern applications.

SD-WAN empowers enterprises to move beyond the constraints of device-centric and circuit-centric frameworks. It embraces a network-wide overlay that abstracts from the underlying hardware.

This forward-thinking network architecture lays out the groundwork for a versatile infrastructure, adept at supporting a hybrid workforce. It enables businesses to seamlessly manage network traffic, optimize application performance, and enhance security across diverse locations and cloud environments. It thereby aligns network functionality with the evolving demands of today’s digital landscape.

How SD-WAN works: architecture and traffic control

SD-WAN is closely associated with the internet and offers enterprises a new way of building their wide area networks. With SD-WAN, enterprises can replace traditional routers with a virtual overlay network by installing an SD-WAN edge device at each branch location. This SD-WAN device serves as a connection point for multiple physical WAN links of any sort to carry business traffic without the need for complex configuration and network engineering.

Due to the principles of SD-WAN, all edge devices are connected to a central software platform, commonly referred to as an orchestrator. It’s here that enterprises can manage, configure, and push out policies instead of having onsite engineers. Additionally, SD-WAN enables intelligent traffic steering and prioritization from the detection of anomalies and performance deviancy.

SD-WAN for multi-cloud and SaaS

SD-WAN plays a critical role in connecting users to applications hosted across multiple public clouds and SaaS platforms, delivering consistent performance, routing control, and policy enforcement across distributed environments, as highlighted in Multi-Cloud Networks and the Role of SD-WAN and Optimizing Multi-Cloud Networks with SD-WAN Solutions.

Key benefits of SD-WAN for enterprise networks​​

SD-WAN plays a critical role in connecting users to applications hosted across multiple public clouds and SaaS platforms, delivering consistent performance, routing control, and policy enforcement across distributed environments, as highlighted in Multi-Cloud Networks and the Role of SD-WAN and Optimizing Multi-Cloud Networks with SD-WAN Solutions.

Increased
cost savings

Due to the use of low-cost internet circuits across the network.

Centralized
management

A central orchestrator that instructs site devices on behavior and configurations.

Simplified and secure
connectivity

Over any (and all) transport layers in the network.

The ability to scale with
the business

Add new sites, and more users to meet the changing demands of the business.

Improved insights and
visibility

With better reporting analytics and capabilities.

Increased network
performance

With centralized communication, and control being pushed to each site.

Coevolve has been helping businesses adopt telco-independent SD-WAN since 2014. Through an “over-the-top” model, our telco-independent SD-WAN offering enables flexibility in choosing various Internet Service Providers (ISPs), allowing for the ideal combination of connectivity providers at each level.

This eliminates the reliance on a single provider and provides flexibility to access local and regional broadband providers, further aiding cost savings and performance. Our approach removes a “one-size-fits-all” model that often compromises the integrity of the SD-WAN solution, limiting the types of software, services, and capabilities accessible to the enterprise. Telco-independent SD-WAN drastically reduces deployment lead times from months to weeks, without the need to wait for existing contracts to expire.

SD-WAN use cases for modern enterprises

SD-WAN supports a broad range of enterprise use cases, from improving SaaS and multi-cloud performance to connecting global branches, integrating remote users, and simplifying legacy WAN transformation.

Coevolve Response Center​

Transform the branch office network

Replace legacy branch infrastructure with centrally orchestrated, highly integrated appliances.

End-to-end security and compliance

Implement advanced security functions directly on the edge to segment workloads and accurately identify intrusion attempts.

Agile branch office deployments

Rapidly deploy new branches using zero-touch provisioning, without the need for local IT support teams.

Enhanced end-user experience

Prioritize critical applications as needed and obtain clear insights into performance bottlenecks for both cloud and on-premises applications.

Cloud networking solutions

Leverage next-gen underlay options

Seamlessly and effectively adopt 5G, LEO satellite, and specialist local providers at every location – all without impacting the solution architecture.

Build cloud-ready infrastructure

Ensure the network and security environment can provide a solid foundation for large-scale digital transformation projects at every level.

Cost-effective network scaling

Meet the ever-growing demands of today’s users and applications without the need for costly infrastructure replacements.

Seamless support for M&A initiatives

Securely integrate new mergers and acquisitions (M&As) within days – and without the need to replace existing network or security infrastructure.
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SD-WAN vs MPLS and traditional WAN

Many enterprises assess SD-WAN as an alternative or complement to MPLS because it offers greater flexibility in transport choice, centralized policy control, and cloud access.
Aspect SD-WAN  Traditional MPLS WAN 
Connectivity  Uses an intelligent overlay across the internet, broadband, LTE, and MPLS where needed.  Relies primarily on MPLS circuits with less flexible transport choices. 
Cloud access  Supports more direct, policy-based access to SaaS and cloud platforms. Often sends traffic through central sites or legacy architectures, which can add latency.
Agility  Central orchestration simplifies policy and path changes across locations. Changes often depend on carrier processes and slower provisioning cycles.
Visibility  Typically offers richer telemetry and application-aware performance insights. Usually provides less application-level visibility.

How to adopt SD-WAN: business case, deployment, and operations

1. Business case

Is your organization moving workloads to the cloud? Do you backhaul internet over MPLS? How are your sites accessing the internet? What are your traffic flows? Do you have an existing MPLS core network? How much are you spending on moves, adds, and changes per year? How much time and effort are invested in the WAN?

These questions and many more are key to a successful business case. It’s important to address these to build a business case baseline and compare any SD-WAN transformation. The good news is that the process won’t take as long as you think.

Coevolve has worked with clients all over the world and understands that over-complicating the business case can be counter-productive in the race to meet business expectations. A simple, methodical approach produces baseline comparisons to drive transformation. Our approach will, at the bare minimum, support your existing needs while unlocking significant upside commercially, technically, and operationally.

2. Technical considerations

SD-WAN can require a new mindset for network architecture, from the underlay circuits to the integration between the overlay and the existing WAN. Here are some technical considerations for the new WAN:

  • Less focus on primary / backup circuits, more on a pool of connectivity: One of the major benefits of SD-WAN is the ability to extract better performance out of multiple circuits than each individual circuit can deliver. Traditional WANs focused on a high-quality primary circuit at each site, with backups in some cases. In an SD-WAN design, multiple low-cost circuits can be used instead. Think of each circuit as “disposable”, meaning the network is not dependent on any single circuit, boosting resilience and reducing network costs.

  • Look at high availability options for resilient sites: Most SD-WAN solutions offer a range of high availability (HA) options, in physical and virtual environments. Hot standby HA solutions are most common, with a second device ready to take over from the first if it fails. More advanced solutions include a distributed HA architecture, with circuits connected to separate appliances and back-to-back connectivity between the appliances to use each circuit. Clustering can be another option to provide HA in addition to better horizontal scaling.

  • Leave forwarding decisions to the SD-WAN whenever possible: It’s tempting to use the policy-based features of an SD-WAN solution to carefully engineer traffic flows and steer specific applications over certain link types. In our experience, it’s often better to leave policies in an automatic mode, where the best path(s) will be selected in real time. In a traditional enterprise WAN, real-time traffic such as voice or video would always be carried over MPLS; this isn’t necessarily the case in an SD-WAN with advanced telemetry.

  • Carefully consider routing protocol integration: As SD-WAN solutions have matured, their routing capabilities have improved significantly. Most major SD-WAN solutions support a range of routing protocols, including OSPF and BGP.

These functions can facilitate the use of the SD-WAN edge as an MPLS CE and integrate with existing networks at data centers. Consider how the underlay and overlay work together in a dynamic routing environment to avoid loops.

3. Operational model

SD-WAN architecture is just one part of the puzzle. How that network is going to be implemented and managed is another puzzle piece, and with new models emerging, enterprises have the ability to pick a model best suited to their needs and resources.

There are three distinct operational models, DIY, managed and co-managed. Many enterprises are now leaning towards managed and co-managed models due to the increased complexity and pressure of enterprise networks requiring more dynamic and specialized support.

4. Security and NFV

Security in SD-WAN solutions is a critical aspect, as the solution not only simplifies network connectivity across multiple locations but can also incorporate advanced security measures.

SD-WAN offers enhanced security by integrating seamlessly with cloud-based security services, providing centralized control over network traffic and policies. This integration allows for streamlined deployment of security updates and policies, ensuring consistent protection across the entire network.

Additionally, SD-WAN can leverage Network Functions Virtualization (NFV) to run virtual firewalls directly at the network edge. This approach localizes security measures, enabling real-time threat detection and response at each network entry point.

By combining the flexibility of SD-WAN with cloud-based security and edge-based NFV firewalls, organizations can achieve a robust, scalable, and highly secure network infrastructure, well-suited for the dynamic demands of modern digital environments.

Telco vs non-telco SD-WAN: why telco-independence matters

When evaluating SD-WAN, enterprises face a critical procurement decision: whether to engage through a carrier-led model or a non-telco partner model – a choice that significantly affects flexibility, cost, and long-term vendor lock-in.

For a detailed comparison, see: Telco vs Non-Telco SD-WAN: Key Differences for Enterprises and Why a Telco-Independent Approach Makes Sense for Global SD-WAN Solutions.

SD-WAN technology and connectivity partners

Coevolve’s telco-independent approach is underpinned by a curated ecosystem of technology and connectivity partners. Our approach is selected to give enterprises access to best-of-breed SD-WAN, security, and connectivity capabilities without lock-in to a single vendor or carrier.

Coevolve has been a VeloCloud partner since 2015 and was one of the first partners to deploy a global SD-WAN solution. Over the past decade, we have supported clients through the platform’s evolution under VMware, Broadcom, and most recently, Arista Networks, while continuing to deliver the same proven SD-WAN capabilities global enterprises rely on.

Today, Coevolve designs, deploys and manages SD-WAN solutions across more than 80 countries. View our full partner ecosystem to learn more about the technology and connectivity providers we work with.

SD-WAN FAQs

What is SD-WAN in simple terms?

SD-WAN is a software-based approach to managing wide area connectivity, allowing enterprises to use multiple connection types more intelligently and apply policies centrally, without the complexity of traditional router-based management. For a non-technical breakdown, read our simplified guide to SD-WAN for enterprises.

SD-WAN can steer traffic over the most suitable path, reduce unnecessary backhaul, and apply policies based on real-time application and network needs. A more seamless user experience is created with cloud and SaaS functions. See Multi-Cloud Networks and the Role of SD-WAN and optimizing multi-cloud networks with SD-WAN for details.

A telco-led model ties the SD-WAN solution closely to a carrier’s network, operations, and commercial structure, while a telco-independent model gives enterprises the flexibility to select suitable underlay providers at each site and access best-of-breed software. See Telco vs Non-Telco SD-WAN: Key Differences for Enterprises for details.

Yes. Modern SD-WAN strategies increasingly extend beyond physical branches to support remote and hybrid work scenarios. This enables the same performance and policies to home office users. It’s a topic we explore in detail in SD-WAN: Great for Offices, but What About Remote Users?

SD-WAN can serve as the connectivity and policy layer that helps enterprises route traffic consistently and efficiency between users, sites and applications distributed across many cloud environments. Our articles on multi-cloud networks and SD-WAN and optimizing multi-cloud networks go into more detail on performance benefits.

SD-WAN platforms can integrate with broader IT operations through APIs and orchestration workflows, enabling automation and tighter integration with existing monitoring, ITSM, and security tools. We explore these capabilities in more depth in Integrating SD-WAN with Existing Systems Using APIs.

Real-world SD-WAN deployments show measurable outcomes across cost, performance, and operational control. 

Examples: MPC Kinetic, an Australian energy and resources firm operating across 15–20 remote sites, replaced its full MPLS network with SD-WAN and reduced connectivity costs by more than 80%. It also cut new site deployment time from months to weeks. 

AutoPacific Group, a global manufacturing business, used SD-WAN to connect sites across multiple continents. SD-WAN helped the company separate an entire corporate network post-acquisition in under a week.