QoS decides who wins when a link is busy. Where steering chooses the path, QoS controls the priority and bandwidth of each traffic class on that path — so a large file sync never starves a phone call.
Traffic classes
Group applications into a handful of classes and treat each consistently:
| Class | Examples | Treatment |
|---|---|---|
| Real-time | Voice, video conferencing | Highest priority, low latency, protected bandwidth. |
| Business-critical | ERP, CRM, line-of-business SaaS | High priority, guaranteed minimum. |
| Standard | Web, email | Normal priority. |
| Bulk | Backups, updates, file sync | Lowest priority; yields to everything else. |
Configure QoS
Map apps to classes
In SD-WAN → Policies → QoS, assign applications (from app recognition) to a class.
Set priorities and guarantees
Give each class a priority and, where needed, a minimum bandwidth guarantee and a cap. Real-time gets a protected slice; bulk gets a ceiling.
Enable per-transport shaping
Set the shaping rate to match each circuit's real throughput so the edge queues correctly before the carrier does.
Prove it with SLA targets
Attach latency, loss, and jitter targets to the real-time and business-critical classes. The edge measures actual performance against those targets and reports it in the Network Portal, so "voice is protected" is something you can show, not just assert — the same SLA-backed WAN performance reporting available for every site.
Tip
Start from the built-in Voice-first QoS template and adjust. It already prioritizes real-time traffic and de-prioritizes bulk, which covers most sites out of the box.