SD-WAN Explained for Multi-Location Businesses
A plain-language explanation of how SD-WAN works, how it compares to MPLS, how it relates to SASE, and what to plan for when moving a multi-site network.
Smart Retail Consulting · · 4 min read
If your business operates more than a handful of locations, your wide area network (WAN) is one of the most important systems you own. It connects stores, offices, clinics, and warehouses to each other, to the cloud, and to the internet. For many years the standard approach was a private network service such as MPLS. Today, a growing number of organizations are moving to software-defined WAN, or SD-WAN.
This article explains what SD-WAN is, why it matters, and what to consider before making the move.
What SD-WAN is
SD-WAN is a way of managing a wide area network through software rather than configuring each router individually. An SD-WAN appliance (physical or virtual) at each site connects to one or more transport links, such as fiber, cable broadband, 5G, or satellite. A central controller manages policies for every site from one place.
The key idea is that the network no longer depends on a single type of connection. It can use several at once and choose the best path for each application in real time.
How it works
- Multiple transports. Each site can use two or more connections from different providers or technologies.
- Application-aware routing. The network identifies traffic, such as voice, video, or point-of-sale, and sends it over the path best suited to it.
- Continuous path monitoring. The appliance measures latency, jitter, and packet loss on each link and shifts traffic when conditions change.
- Centralized orchestration. Policies are defined once and pushed to every site.
- Zero-touch provisioning. New sites can often be brought online by shipping a pre-configured appliance and plugging it in.
SD-WAN compared with MPLS
| Consideration | Traditional MPLS | SD-WAN |
|---|---|---|
| Transport | Private circuits from one carrier | Any mix of broadband, fiber, wireless, satellite |
| Change speed | Changes often require carrier orders | Policy changes made centrally |
| Cloud access | Traffic often routed through a data center | Direct, policy-based access to cloud services |
| Resilience | Depends on carrier design | Multiple diverse links per site |
| Visibility | Limited, carrier-dependent | Application-level monitoring |
MPLS still has a place, particularly where predictable private connectivity is a requirement. Many organizations run both during a transition, or keep MPLS at a few critical sites.
Benefits for multi-location businesses
Better application performance. Critical applications can be prioritized and steered around a degraded link.
Higher resilience. With two diverse connections and automatic failover, a single circuit outage is less likely to take a site offline.
Faster site openings. Sites can launch on whatever connectivity is available and add or change links later.
Simpler operations. Policies, updates, and monitoring are managed from one console.
More flexibility in sourcing. Because SD-WAN works over many transport types, you have more choice in providers and contracts.
Where SASE fits
Secure Access Service Edge (SASE) combines SD-WAN with cloud-delivered security services, such as secure web gateways, cloud access security brokers, zero trust network access, and firewall as a service. The goal is to apply consistent security to every user and site, whether traffic is headed to a data center, a cloud application, or the internet.
Not every organization needs a full SASE architecture on day one. But security should be part of SD-WAN planning from the start. See our Cybersecurity & Network Security overview for how we approach this.
Managed, co-managed, or self-managed
- Fully managed: A provider designs, deploys, monitors, and supports the network. Best for lean IT teams.
- Co-managed: The provider handles infrastructure and monitoring while your team retains control of policy.
- Self-managed: Your team buys the platform and runs it. Best for organizations with deep networking expertise.
Planning checklist
- Inventory every site, circuit, contract, and end date.
- Identify critical applications and their performance needs.
- Decide on the transport mix for each site, including true path diversity.
- Choose a management model and security approach.
- Evaluate vendors and service providers side by side.
- Pilot at a small number of representative sites.
- Sequence the rollout around contract end dates and business calendars.
Common mistakes
Buying two links that share a path. Two connections from the same provider, or on the same physical route, may fail together. Diversity should be verified, not assumed.
Treating security as an afterthought. Direct internet access at branches changes your security model and must be planned.
Ignoring existing contracts. Early termination fees on legacy circuits can erase expected savings if the migration is not timed well.
Under-sizing broadband. Cheaper links still need enough capacity for peak demand.
How we help
Our SD-WAN & Enterprise Networking engagements start with a current-state assessment, compare architectures and providers transparently, and produce a phased migration plan. Where satellite or 5G belongs in the transport mix, we design it in. For background on satellite, read Starlink for Business.
Schedule a consultation to discuss your network.
Editorial note: this article is a draft. Facts and service details should be reviewed before publication.