SASE (Secure Access Service Edge)

What is SASE (Secure Access Service Edge)?

SASE is a converged network security solution that connects users, devices, systems and remote networks to apps and resources using a combination of software-defined wide area networking (SD-WAN) along with security functions like ZTNA, CASB, FWaaS and SWG. This unified solution promises simplified WAN deployments, improved efficiency and security, and application-specific bandwidth pieces.

The following diagram represents the SASE architecture as described by Gartner:

Legends used:

ZTNA = Zero Trust Network Access: Provides adaptive access control.

SWG = Secure Web Gateway: Filters and secures internet traffic.

CASB = Cloud Access Security Broker: Enforces security policies for cloud services.

FWaaS = Firewall as a Service: Protects online data and applications

What are the key challenges businesses face in enabling secure access?

Many organisations still rely on legacy infrastructure—typically VPNs connecting back to HQ or a data centre—for all access needs. But this model struggles to keep up with hybrid work and the shift towards cloud-based, distributed applications. Here’s why:

1. Fragmented security experience

Security policies often vary based on where users are and how they connect. A remote user—viewed as untrusted—must connect via VPN, while someone in a branch office might be granted direct access with fewer checks. On top of that, personal or BYO devices accessing the internet from outside the corporate network don’t benefit from consistent protection. If malware slips through on an unmanaged device, it can laterally spread once that device reconnects inside the office.

2. Limited visibility over SaaS usage

Traditional network security, anchored at HQ or a data centre, doesn’t have line-of-sight into cloud traffic. This lack of visibility makes it difficult for IT to detect risky behaviour, enforce policies, or protect sensitive data in SaaS environments accessed remotely.

3. Performance and security trade-offs with VPNs

Routing all traffic through a central VPN might tick the compliance box, but it often frustrates users with sluggish performance—especially for SaaS and internet-based services, thereby impacting the User Experience. Worse still, VPNs typically give users wide access to the corporate network rather than restricting access to only the apps they need. This broad access increases the risk of lateral movement if an attacker gains entry.

Why do businesses choose SASE?

At its heart, SASE runs on a Zero Trust security model, which basically means “never trust, always verify.” Every user, device, and app gets checked and re-checked, no matter where they are. This ongoing verification is key to keeping things secure.

What makes SASE stand out is how it brings networking and security together in one cloud-delivered setup. Instead of juggling outdated, disconnected tools, it rolls everything into one streamlined system—more efficient, more scalable.

There are two main parts to SASE: on-premise security and networking via SD-WAN, and Cloud-delivered Security Service Edge (SSE). SSE helps keep remote workers secure and visible across the board. Inside SSE, there are a few essential layers:

• Secure Web Gateway and Firewall-as-a-Service, which protect users and devices from online nasties
• ZTNA (Zero Trust Network Access), giving identity-based access with tight controls
• CASB (Cloud Access Security Broker), which looks after access to SaaS tools and protects sensitive data

By combining SD-WAN and SSE, SASE delivers a seamless, secure digital experience from end to end. Whether people are working from home, the office, or somewhere in between, access stays protected and performance stays sharp. It also makes life easier for IT teams, freeing them up to focus on the bigger picture.

What are the main benefits of SASE?

 SASE (Secure Access Service Edge) offers a unified platform that merges security and networking into a single, cloud-delivered model. By integrating key capabilities like ZTNA, CASB, firewalls, proxies, and DLP, organisations can achieve a consistent and comprehensive approach to secure access—regardless of where users, apps, or data reside.

Centralised Management Across Environments

A well-designed SASE solution enables central visibility and control across on-premises, cloud, and hybrid environments. This unified architecture simplifies policy management, device onboarding, traffic inspection, and lifecycle operations—streamlining everything from day-to-day security tasks to long-term network planning.

Real-Time Security with Continuous Verification

Rather than relying on one-off authentication, SASE applies continuous posture checks on users and devices. This helps enforce dynamic, risk-based access decisions and better protects organisations from modern threat tactics like lateral movement or session hijacking.

Scalable Performance Without Compromise

SASE is built for the cloud—designed to elastically scale with user demand while maintaining high throughput and advanced features like SSL decryption. It supports distributed workforces and reduces bottlenecks, delivering a responsive digital experience without sacrificing protection.

Predictable Costs and Reduced Complexity

By consolidating multiple legacy tools and vendors into one platform, SASE lowers the total cost of ownership. Organisations benefit from fewer SKUs, simplified licensing, and flexible usage models—helping them align spend with actual usage and growth patterns without heavy infrastructure overhead.

Future-Proof Security Architecture

As network perimeters dissolve and cloud adoption accelerates, SASE provides a future-ready framework that keeps security close to the user and the app. It supports agile access policies and enables IT teams to respond quickly to new business requirements or emerging threats.