SD-WAN is networking: it connects your offices over several circuits and sends each application down the best path. SSE, short for security service edge, is security delivered from the cloud: a secure web gateway, zero trust network access to private applications and a cloud access security broker, applied to each user wherever they work. SASE, secure access service edge, combines the two under one policy, so the SASE vs SSE question comes down to whether the network between your sites is part of the package.
If your immediate question is how to replace a remote-access VPN, start with our VPN vs ZTNA guide. This guide covers the wider choice: what each model is, how they fit together, where MPLS sits, what they cost and what a small team should do first.
What is the difference between SASE, SSE and SD-WAN?
The three overlap, which is why vendors blur them. The clearest way to separate them is by what each one connects or protects.
| SD-WAN | SSE | SASE | |
|---|---|---|---|
| What it is | An overlay network across one or more circuits at each site | Cloud-delivered security for users and applications | SD-WAN and SSE delivered as one service |
| Problem it solves | Fragile or slow links between sites, and internet traffic routed through headquarters | Securing remote users, SaaS and private apps without a VPN | Both, under one policy and one console |
| Main parts | Edge devices, central management, path selection, encryption between sites | Secure web gateway (SWG), zero trust network access (ZTNA), cloud access security broker (CASB) | All of these |
| Where it runs | At each site | In the provider's cloud, with a client on each device | At each site and in the cloud |
| Connects or protects | Sites and the traffic between them | Users and devices, wherever they are | Sites, users and devices |
| Usually replaces | Hand-built site-to-site VPNs and single-circuit sites, sometimes MPLS | Remote-access VPNs and on-site web proxies | Over time, branch VPNs and proxies as well |
| Pricing unit | Per site or device, plus the circuits | Per user per month | Per user and per site |
| Fits | Two or more sites with several circuits | Remote or hybrid teams on cloud apps | Several sites plus remote staff wanting one policy |
What is SD-WAN?
Mplify, the industry standards group formerly called MEF, defines an SD-WAN service in MEF 70.2 as a connectivity service that creates an overlay network over one or more underlying connections, recognizes application flows and forwards them according to policies. Paths are chosen dynamically to meet each policy, and the service can encrypt traffic between SD-WAN edges. In plain terms: a device at each site that watches several internet or carrier circuits and sends calls, video and file transfers over whichever path is performing best at that moment.
What is SSE?
Microsoft's documentation explains the category in one line: as applications and data move to the cloud, the workforce needs an identity-aware, cloud-delivered network perimeter, and that category is called security service edge. Microsoft's own SSE pairs Microsoft Entra Internet Access, an identity-based secure web gateway, with Microsoft Entra Private Access, zero trust network access that reaches private apps without a VPN, and uses Defender for Cloud Apps as the CASB. The idea underneath is the one in NIST SP 800-207: no implicit trust based on a user's or device's network location.
What is SASE, and how is it different from SSE?
SASE adds the network. Mplify's SASE standard, Mplify 117.1, describes a SASE service as one that enables secure access and secure connectivity of users, devices or applications to resources, lists a policy-driven networking technology such as SD-WAN among its parts, and recommends SD-WAN for the connections between SASE edges. So SSE is SASE without the SD-WAN half: it secures users and applications but does not manage the links between your offices.
SASE is bought two ways. One vendor can supply both halves in one product and console, which gives you a single policy model. Or an SD-WAN from one vendor connects to an SSE from another; Microsoft's Global Secure Access, for example, can take branch traffic through a remote network connection. The second route lets you keep firewalls you already own.
SASE vs SD-WAN: do you need both?
- SD-WAN alone fits a business with several sites whose problem is connectivity: unreliable links, a second circuit nobody uses, or sites that go dark when one line drops.
- SSE alone fits a remote or hybrid team on cloud applications with one office or none, where the problem is securing users rather than links.
- SASE fits several sites plus remote staff, when you want one policy for both and are ready to retire branch VPNs and on-site proxies over time.
Whichever you choose, watch the path your traffic takes. Microsoft's Microsoft 365 network connectivity principles warn that routing traffic through an intermediate security stack or cloud web gateway before it reaches Microsoft 365, a network hairpin, adds latency, and recommend local internet egress and sending trusted Microsoft 365 traffic directly. A good SSE or SASE design does exactly that.
Where does MPLS fit?
MPLS is a private carrier network between sites, so it sits underneath this choice rather than beside it. SD-WAN can run over MPLS, over internet circuits or over both, which is how a business can move off MPLS one site at a time and then add SSE on top. Our SD-WAN vs MPLS guide covers that decision.
Which fits a small team?
For a small business on Microsoft 365, this order usually pays off:
- Identity first. MFA and Conditional Access on every account, and device compliance through Intune. SSE policies build on it.
- Replace the open VPN with zero trust network access for the private apps people still reach remotely.
- Add web filtering through a secure web gateway, so users are protected off the office network too.
- Add SD-WAN only when you have two or more sites with more than one circuit each.
- Consider full SASE when you have several sites and a remote workforce, and the separate pieces have become hard to manage.
What affects cost, implementation and support?
- Pricing units differ. SSE is priced per user per month; SD-WAN per site or device, plus the circuits; SASE combines both. As of October 2026, Microsoft lists Microsoft Entra Internet Access and Microsoft Entra Private Access at $5 per user per month each, or both inside the Microsoft Entra Suite at $12 per user per month, paid yearly; users also need Microsoft Entra ID P1 or P2, with P1 listed at $7.
- Branch connectivity has a threshold. Microsoft's remote network feature for branch offices needs at least 50 Entra ID P1 and Internet Access licenses combined.
- Implementation means a client on every device, an inventory of the private apps people use, decisions about TLS inspection and web categories, and for SD-WAN, edge devices and new circuits with carrier lead times.
- Support is policy work: tuning web filtering, adding apps, reading logs and keeping edge firmware patched.
How does NetSys approach SD-WAN, SSE and SASE?
We start with the problem, not the acronym. Our network security services cover firewall rule ownership, segmentation between staff, guest and device networks, secure remote access with named accounts and MFA, and monitoring with escalation to named contacts. We install and manage Cisco Meraki MX and Fortinet FortiGate firewalls, and specify Fortinet where a site needs SD-WAN across several circuits. Our zero trust work, delivered in phases with Entra ID, Intune and Defender, replaces an always-open VPN with zero trust network access in its network phase. Engineers work on site across New York City, Long Island, Westchester, the Hudson Valley, North Jersey and Fairfield County, CT; elsewhere we work remotely from Brooklyn, with visits scoped per engagement.
Book a call with an engineer to map your sites, remote users and applications, and find out which pieces you actually need.
Frequently asked questions
Is SSE the same as SASE?
No. SSE is the security half of SASE: a secure web gateway, zero trust network access and a CASB delivered from the cloud. SASE adds SD-WAN, so it also manages the connections between your sites. A business without branch offices often needs only SSE.
Does SASE replace SD-WAN?
No, it includes it. SASE is SD-WAN plus cloud-delivered security under one policy. If you already run SD-WAN, you can add SSE beside it and connect the two instead of replacing equipment that works.
Does SSE replace a VPN?
Its zero trust network access piece usually replaces a remote-access VPN, giving users access to specific private applications instead of the whole network. Microsoft, for example, describes Entra Private Access as reaching private apps without a VPN. Links between offices are a separate question for SD-WAN or a site-to-site VPN.
Is SASE worth it for a small business?
Usually not as a first step. Most small businesses get more from MFA, device compliance and replacing the VPN with zero trust access, then SD-WAN if they have several sites. Full SASE starts to pay off when several sites and a remote workforce need one policy.
MPLS vs SD-WAN vs SASE: how do they relate?
MPLS is private carrier transport between sites. SD-WAN is an overlay that can run over MPLS, internet circuits or both and choose between them. SASE adds cloud security for users and traffic on top of SD-WAN, so a business can move from MPLS to SD-WAN first and add SSE later.
Which option fits a small team?
Identity controls and zero trust access first, which is the core of SSE, then SD-WAN when you have two or more sites with several circuits. Treat full SASE as the destination for a multi-site, hybrid business, not the starting point.
What affects the cost of SASE, SSE or SD-WAN?
Users for SSE, sites and devices for SD-WAN, and both for SASE, plus circuits, setup time and ongoing policy work. As of October 2026, Microsoft's SSE pieces list at $5 per user per month each, or $12 together in the Entra Suite, with Entra ID P1 or P2 required.
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