SASE: Networking and Security, Converged in the Cloud
SASE, Secure Access Service Edge, is the convergence of wide-area networking and network security into a single, cloud-delivered service. It combines SD-WAN with a set of cloud security functions, secure web gateway (SWG), cloud access security broker (CASB), zero-trust network access (ZTNA) and firewall-as-a-service (FWaaS), so users reach applications securely from anywhere. The security half is often called SSE, Security Service Edge.
The old model, route everyone through the data center and inspect at the perimeter, made sense when applications and users lived in the office. They do not any more: applications are in the cloud, and users work from everywhere, and backhauling all of it through a central firewall is slow and expensive. SASE moves security to the cloud edge, close to the user and the application, and ties it to the SD-WAN so networking and security are one system.
What SASE Includes
- SASE is a set of converged capabilities, not a single box:
- SD-WAN: the network fabric that connects sites and users, on Cisco Catalyst SD-WAN or Meraki.
- Secure web gateway (SWG): inspects and filters web and internet traffic.
- Cloud access security broker (CASB): controls how SaaS applications and data are used.
- Zero-trust network access (ZTNA): per-application, least-privilege access that replaces the VPN.
- Firewall-as-a-service (FWaaS): cloud-delivered firewalling for every user and site.
- DNS-layer security: blocks threats at the DNS layer before they reach the user, with Cisco Umbrella.
Why SASE? Why It Matters Now
- Built for hybrid work: security that follows the user from office, home or branch.
- Cloud-first: protection close to the application, not backhauled through the data center.
- Zero trust: per-app access that verifies every request and shrinks the attack surface.
- One converged stack: networking and security managed together, not two silos.
- Better experience: direct, low-latency access to SaaS, secured in the cloud.
- Consolidated and simpler: fewer point products, one policy, one vendor stack.
The VPN is the clearest symptom of the old model. It grants broad access to the whole network once a user connects, it backhauls traffic through a chokepoint, and it is a favourite target for attackers, because one stolen credential opens the door to everything. Zero-trust access flips that: it verifies every request, grants access to one application at a time, and hides everything else.
But SASE is a journey, not a switch you flip. It usually starts from the SD-WAN and the security you already have, and adds cloud security functions in the order that matters most, often DNS-layer security and secure web gateway first, then ZTNA to retire the VPN. Done well it consolidates a pile of point products; done badly it becomes another silo.
Proactive Data Systems designs SASE on Cisco Secure Access and Cisco Umbrella, built on your Cisco SD-WAN, and phases the rollout around your priorities, replacing the VPN with zero-trust access, moving security to the cloud edge, and keeping networking and security as one design.
What SASE Is Made Of
SASE is not one product but a set of converged capabilities. The table below sets out the parts and how Cisco delivers them.
| Capability | What it does | Cisco delivers with |
|---|---|---|
| SD-WAN | Connects sites and users, steers traffic | Cisco Catalyst SD-WAN, Meraki |
| Secure Web Gateway (SWG) | Inspects and filters web and internet traffic | Cisco Umbrella, Secure Access |
| CASB | Controls SaaS application and data usage | Cisco Umbrella, Secure Access |
| Zero-Trust Access (ZTNA) | Per-application, least-privilege access | Cisco Secure Access, Cisco Duo |
| Firewall-as-a-Service (FWaaS) | Cloud-delivered firewalling for users and sites | Cisco Secure Access |
| DNS-layer security | Blocks threats at the DNS layer, before connection | Cisco Umbrella |
You rarely deploy all of it at once. Proactive sequences the components to your risk and your estate, usually starting with DNS and web security and moving toward full zero-trust access.
VPN or Zero-Trust Access: Why ZTNA Wins
The most immediate SASE win is replacing the remote-access VPN with zero-trust network access. The table below shows why.
| Aspect | Traditional VPN | Zero-Trust Access (ZTNA) |
|---|---|---|
| Access | Full network once connected | One application at a time, least privilege |
| Trust | Trusts the device on the network | Verifies every request, trusts nothing |
| Attack surface | Broad, lateral movement possible | Minimal, applications hidden until authorised |
| Experience | Client and backhaul, slower | Direct, cloud-delivered, faster |
| Best for | Legacy remote access | Modern remote and hybrid work |
ZTNA does not require ripping out everything on day one; it can run alongside the VPN and take over application by application. Proactive plans that enable migration so that remote access improves without a risky cutover.
SASE Across India: Why the Estate and the Rules Decide the Design
India's enterprises face the same shift as everywhere, hybrid work, cloud applications and a rising threat level, but with their own constraints: data-residency rules, variable connectivity, and security teams stretched across many sites.
Where inspection happens, how remote users connect, and how SASE meets India's data-residency and compliance expectations all shape the right design here rather than on a datasheet. Proactive has designed and delivered Cisco SASE and zero-trust access across manufacturing, BFSI, healthcare, IT and ITeS and GCC environments in Delhi, Mumbai, Bengaluru, Pune and Hyderabad, phased to the estate and the risk.
Proactive Data Systems: The Partner That Converges, Migrates, and Manages
Buying a SASE licence is easy. Converging networking and security without breaking either, retiring a VPN people depend on, and running it day to day, is the part that rewards experience.
Proactive brings over three decades of enterprise infrastructure delivery, certified Cisco networking and security engineers and an ISO 9001:2015 quality system. As a Cisco Preferred Partner certified across all five Cisco architectures, Networking, Security, Collaboration, Cloud and AI, and Services, we design SASE on Cisco Secure Access, Umbrella and Duo, built on Cisco SD-WAN.
SASE sits where networking meets security. It builds on SD-WAN and works alongside Campus and LAN Switching, Wi-Fi Networking, Secure Networking, and AI-Driven Networking, and connects to our broader Cybersecurity practice for detection and response.
From assessment and design through phased rollout, VPN migration and managed operations, backed by a 24/7 service desk, Proactive delivers SASE that secures every user without slowing them down.
