SD-WAN Explained: How Software-Defined WAN Works
A traditional WAN connects branches to a data centre over fixed circuits, configured router by router. SD-WAN adds a software layer that treats every available link as part of one network and decides — application by application, moment by moment — which link to use.
The building blocks
- Edge devices at each site that connect to all available links: MPLS, broadband, 4G/5G.
- An overlay of encrypted tunnels between sites, independent of the underlying carriers.
- A central controller and orchestrator that holds policy and pushes it to every edge.
Application-aware routing
The edge devices continuously measure latency, jitter and packet loss on every path. Policies say, for example, that voice must use the path with the lowest jitter, video calls must avoid paths with loss above 1%, and backups may use whatever is cheapest. If a link degrades, affected traffic moves to another path in under a second.
What organisations gain
- Higher total bandwidth by using every link actively
- Better SaaS and cloud performance through local internet breakout
- Faster new-site deployment with zero-touch provisioning
- Central visibility of applications and link quality
- Often lower cost by reducing dependence on MPLS
What it does not do by itself
SD-WAN cannot make a bad link good, and local internet breakout must be secured. Plan link diversity and security together with the SD-WAN design.
Ubixe Infotech designs, deploys and runs managed SD-WAN. See our SD-WAN service or request an assessment.
