But in the modern world, the way we consume services has changed. As have our expectations. From cloud-based applications to video services and voice tools, we’re frequently opting for internet-based solutions that help us get quicker, more convenient outcomes that meet our needs instantly.
The importance of SD-WAN in 2025
The evolution in the way we consume technology has also made its way into our work environments, especially with the increase in remote or hybrid working, and the ability for business applications to be accessed from multi-cloud environments, including public cloud over the internet. This results in a greater reliance on network quality and availability from anywhere over natively unreliable, insecure connections.
SD-WAN helps meet those requirements, supporting business’ ambitions to grow and reach their digital innovation and transformation goals. It provides their workforce with the secure reliable connectivity necessary to complete their jobs effectively from any location
Managed SD-WAN services offer businesses the ability to efficiently adopt new applications across various cloud environments for their distributed workforce. These services can provide network security management for compliance with cyber security regulations.
What does SD-WAN stand for?
SD-WAN stands for ‘Software-defined wide area network', and refers to the process of using software to securely connect users to applications. SD-WAN architecture allows organisations to connect and extend enterprise networks that are geographically dispersed.
Why is SD-WAN needed?
Long gone are the days of those dreaded dial-up connections. Now, almost every business in the UK is utilising the cloud. Previously, users would connect back to their company data centre to access business applications, but the majority of these can now be quickly and easily accessed via the cloud.
Because of this shift, traditional WAN is no longer suitable in many cases, and SD-WAN has become a vital component of any company's connectivity stack. The SD-WAN model fully supports applications hosted in dispersed locations, including public and private clouds, SaaS services, and on-premise data centres.
SD-WAN also simplifies WAN and bandwidth efficiency, enabling users to seamlessly access their business applications without the latency and poor application performance often found with WAN connections.
Modern businesses need SD-WAN architecture to enable an efficient and simple on-ramp to the cloud that improves application performance and business productivity, without compromising on security and data privacy.
When combined with edge computing, SD-WAN delivers the resources and connectivity users need to enhance application performance and minimise latency. It enables them to have access to their resources in proximity to their location for a greater user experience.
A secure SD-WAN approach is critical due to the increased complexity of cyber security threats and the greater level of exposure as a result of providing users with more flexible and direct access to business applications in public-cloud environments.
Additionally, a secure SD-WAN approach combines network security with central management to assess risk exposure and enforce global security policies across the SD-WAN infrastructure. A Secure SD-WAN is foundational for a seamless transition to SASE. It enables organizations to protect their investment and simplify operations along their journey to a zero-trust architecture.
How SD-WAN works
To support cloud-first enterprises, SD-WAN delivers an application-quality of experience for users that is superior to other conventional methods like router-centric models. Here's how SD-WAN works:
Centralised control & intelligent traffic routing
Uses a centralised control function to securely and intelligently direct traffic across the WAN to trusted SaaS and IaaS providers, as well as public and private cloud providers.
Delivers elevated levels of cloud performance, greater agility, protection from threats, and an improved user experience.
Encrypted tunnels between sites
An SD-WAN device at each site automatically downloads custom-defined configuration and traffic policies to establish tunnels when connected to local networks.
Routing and traffic control are managed by the SD-WAN, ensuring outbound traffic is directed along the best path depending on application policies and real-time traffic conditions.
Pre-configured policies to effectively manage traffic
SD-WAN devices automatically fail over to alternative connections should other connections fail.
Policies determine dynamic path selection, directing traffic to the best route depending on the priority level and quality of service given to the application.
What problems does SD-WAN solve?
SD-WAN isn’t just an enabler that helps businesses access cloud-based applications securely and seamlessly, it also solves other problems that can occur when using traditional WANs.
Network complexity
With more remote and hybrid working solutions in place, and increased reliance on hybrid WANs and cloud-based applications, there is greater network complexity than ever before. Previously, WANs could not be easily scaled to meet this demand on networks, but the simplicity of SD-WAN management means there is a solution.
If technical support teams need to travel to remote locations as part of a complex network to configure routers and gateways on an individual basis, the process is time-consuming and can harm productivity.
SD-WAN enhances public network performance by:
Dynamically selecting the best path for traffic
Continuously monitoring WAN link health
Reserving reliable connections for business-critical applications
Managing equipment from one central location
Enabling teams to better control complex networks and respond quickly to the changing business landscape
The technology has also evolved further, with the development of Secure Access Server Edge (SASE). This enables even greater security by pushing multiple layers of network security closer to the users, devices, cloud infrastructures and applications being protected.
Poor public network performance
Latency and performance uncertainty are common issues when networks rely on the internet for WAN connectivity. Time-of-day congestion and transmission types can also impact bandwidth constraints.
SD-WAN improves public network performance by using dynamic path selections to push traffic down the best available path, carefully monitoring the health of each WAN link, and ensuring the most reliable connections are reserved for critical traffic essential for business operations.
MPLS limitations
For traditional WAN connectivity, multiprotocol label switching (MPLS) has been a key component. But while it delivers guaranteed bandwidth, privacy, and predictable latency, it’s expensive and is not flexible. And with increased cloud usage, MPLS does not always offer an efficient means of cloud connectivity.
To combat the high costs and limitations of MPLS, many businesses are utilising broadband internet, although this comes with its own issues around reliability and latency. So, hybrid-WAN connections have become a compelling option, with business-critical applications sent via MPLS and everything else routed over broadband internet.
To set up a hybrid WAN, the capabilities of policy-based management and dynamic path selection of software-defined WAN can be used to strike a balance between cost, reliability, and performance to enable a diverse mixture of application traffic.
What are the benefits of SD-WAN?
As well as the problems solved by SD-WAN, there are additional benefits to choosing this connectivity option.
Cost savings
Diverts non-critical WAN traffic to broadband
Lowers operational costs by enabling remote deployment and reducing site visits
Speed of deployment
Remote working can be enabled quickly and at scale
Any user can plug in the SD-WAN appliance after design in the central management console
No need for travel to remote locations, speeding up remote deployment
Application performance
Link health monitoring in real-time improves performance and application availability
Changes can be made quickly, based on application requirements
No need for traffic to be backhauled through a central point of internet access, reducing latency
Agility
Network engineers can respond to WAN service requests promptly
Traffic can be quickly rerouted thanks to real-time traffic management
Traditional WAN / MPLS vs SD-WAN
The key difference between Traditional WAN / MPLS and SD-WAN is that MPLS is a dedicated circuit and SD-WAN is a virtual overlay that is decoupled from physical links. While MPLS is better at preventing packet loss, it does tend to be a more expensive option. Additionally, SD-WAN's virtual overlay means you can use various connection types including LTE, MPLS, and broadband for greater agility, scalability, and cost savings.
MPLS pros
High reliability - Ethernet provides consistent, low-latency connections
Quality of service (QoS) - Built-in traffic prioritisation
Security - Private network, reducing the attack surface
MPLS cons
High cost - Expensive Ethernet compared to broadband WANs
Long provisioning time - Can take weeks or months to provision new sites
Lack of agility - Not easily scalable or flexible
Limited cloud optimisation - Not built for dynamic cloud workloads
SD-WAN pros
Cost-effective - Can use inexpensive broadband links
Flexibility & agility - Fast deployment
Cloud friendly - Connects securely to cloud services
Centralised management - Simplified policy control
Improved performance for business-critical apps - Dynamic path selection
SD-WAN cons
Variable performance - (if using broadband links)
Security responsibility - Requires additional security tools NOT with secure SD-WAN
QoS limitations - To be configured correctly for dynamic apps and traffic flows
SD-WAN & security: Why it's crucial for modern networks
A secure SD-WAN is crucial to modern networks, using central network performance and security policy management tools to optimise and protect the network. A secure SD-WAN is a must due to the increased complexity of cyber security threats and the wider threat exposure from SD-WAN alone, such as:
Increased vulnerabilities from increased internet access points: SD-WAN introduces new security risks, exposing networks directly to the internet from multiple sites rather than on central internet breakout location which exposes customers to more vulnerabilities and cyber attacks.
Complexity with consistent security policy enforcement: The flexibility of SD-WAN complicates consistent security policy enforcement across all devices and locations.
How secure SD-WAN enhances cyber security (e.g. encrypted tunnels, Zero Trust integration
Secure SD-WAN enhances cyber security by integrating advanced security features like next-generation firewalls, intrusion prevention systems, and encryption, along with centralised security policy management and micro segmentation. This offers a more robust and flexible network security solution than traditional VPNs.
Next-Generation Firewalls (NGFW): SD-WAN solutions include NGFW, offering application-aware firewall capabilities, intrusion prevention, and threat detection.
Intrusion Prevention Systems (IPS): IPS identify and block malicious traffic, guarding against cyber threats.
Micro-segmentation: Isolates network segments to limit the impact of breaches and enhance security.
The role of SASE in SD-WAN security
SASE plays a crucial role in enhancing SD-WAN security by integrating networking and security functions into a unified cloud-delivered platform. This provides comprehensive protection and optimisation for users, devices, data, and applications, regardless of their location.
SASE (Secure Access Service Edge) combines SD-WAN capabilities with security services like Secure Web Gateway (SWG), Cloud Access Security Broker (CASB), Firewall-as-a-Service (FWaaS), and Zero Trust Network Access (ZTNA).
Common security threats and how SD-WAN mitigates them
Secure SD-WAN with a multi-layered security approach addresses common network security threats through a variety of different ways.
Next-Generation Firewalls (NGFW): NGFWs integrated with SD-WAN provide threat detection and filtering, blocking unauthorised access or malware before it reaches the network.
Threat intelligence feeds: Secure SD-WAN solutions use real-time threat intelligence feeds from various sources to identify and block traffic from known malicious IP addresses or suspicious domains. This helps protect the network from emerging threats.
Traffic inspection & redirection: Secure SD-WAN dynamically routes traffic based on security policies and application performance, directing traffic through secure channels if detected as malicious or compromised.
Audit logs and alerts: Detailed audit logs of network access and security events are maintained. Alerts can notify administrators of unauthorised access attempts or abnormal traffic behaviour, enabling prompt investigation and response.
Key features to look for in an SD-WAN solution
WAN traffic visibility and application-aware routing
Deep packet inspection (DPI) for detailed application traffic identification and analysis.
Real-time and historical reporting on bandwidth utilisation, application performance, and network health.
Customisable traffic routing policies based on application criticality (e.g., VoIP or video conferencing getting higher priority).
Security features
Integrated firewall (next-gen firewall capabilities like URL filtering, intrusion detection, etc.).
Secure direct-to-cloud connections (for SaaS, IaaS, etc.) without backhauling traffic.
Zero Trust security models and user authentication.
Managed services provider SLAs & skillset
Proactive 24/7 support and dedicated customer service managers.
Incident and performance SLAs with clear application performance metrics (latency, uptime, etc.).
Comprehensive software patching schedule for all points of network infrastructure exposed to external attack
Top level of certifications and vendor partnership for your Managed Service provider for SD-WAN and all associated technologies, ZTNA, SSE SASE etc
Nasstar solutions for SD-WAN
Nasstar’s SD-WAN solutions ensure cloud-first, security-sensitive organisations can adapt to the dynamic nature of digital innovation. Our scalable and high-performance solutions help support remote sites, latency-sensitive business-critical applications, and increased cloud services.
With a networking approach that provides access to core applications with advanced reporting, our teams can deliver an optimal mix of security and SD-WAN functionality to give you complete peace of mind.
Future trends: What's next for SD-WAN?
As SD-WAN continues to evolve, we expect to see several key threads emerging and improving the SD-WAN experience.
AI-driven SD-WAN & SD-Branch
AI-driven SD-WAN solutions are expected to enhance both performance and user experience by optimising traffic flow and anticipating network issues. This will ensure the smooth operation of critical business applications and improve overall user satisfaction.
Security is also strengthened with AI-driven threat detection and anomaly identification, providing robust protection against advanced cyber threats.
Enhanced automation
With automation tools, managing extensive networks can be simplified by automating complex network tasks, reducing manual efforts and increasing efficiency. This will allow IT teams to focus on strategic tasks, reducing manual efforts and increasing efficiency.
SASE
As businesses increasingly rely on cloud services and SaaS applications, there is a growing need for flexible and secure networking solutions to meet the evolving demands of their cloud infrastructure. This shift underscores the importance of SD-WAN and SASE in providing the necessary adaptability and security.
The rise of remote and hybrid work models also emphasises the importance of SD-WAN solutions that can deliver a consistent and secure user experience across various locations. Ensuring reliable and efficient network performance is crucial for supporting distributed workforces and maintaining productivity.
SD-WAN at Nasstar
If you’re keen to understand more about SD-WAN and how it can help transform your business, speak to a specialist today.
