Before you use SD-WAN monitoring data to make decisions about your network, we recommend that you establish baseline values that are specific to your network. To do this, note the average loss, latency, and jitter values calculated for an extended period of time. As a best practice, we recommend that you consider the average values for the last 24 hours. In a stable, healthy network, average values for the last 20 minutes might suffice.
Many factors can affect the loss, latency, and jitter data reported on the SD-WAN page. For example, the quality of your WAN links and Link Monitor targets can affect the data points and averages you see on the SD-WAN page.
Each network is different, and some applications are more sensitive to performance issues. For these reasons, you must interpret SD-WAN monitoring data based on your knowledge of your network. For reference, this list shows general interpretations of loss, latency, and jitter values.
| SD-WAN Measure | Good | Performance Impacted | Performance Significantly Impacted | Effectively Down |
|---|---|---|---|---|
| Loss | <1% | 1–2% | 2–5% | >5% |
| Latency | <100ms | 100–200ms | 200–400ms | >400ms |
| Jitter | <20ms | 20–50ms | 50–100ms | >100ms |
In Fireware Web UI, you can see historical data for periods of time up to seven days. When you select a single interface, a calculated average appears for that time period.
Default Values for SD-WAN Measurements
The values you specify for SD-WAN measurements determine when failover occurs to another SD-WAN interface. In Fireware v12.5.4 or higher, the default values are:
- Loss rate — 5%
- Latency — 400 ms
- Jitter —100 ms
For information about jitter calculations, go to How is Jitter Calculated? in the WatchGuard Knowledge Base.
In Fireware v12.5.3 or lower, the default values for some measurements are lower: the default latency value is 20 ms, and the default jitter value is 10 ms. If you keep these default values and experience early failover on your network, we recommend that you increase these values.
SD-WAN Failover from an MPLS Link to a BOVPN Virtual Interface Tunnel