Understanding SD-WAN performance

Question

I wanted to understand how does Sophos firewall measure Latency, Jitter and Packet loss. Is it measuring these metrics between the firewall and the WAN gateway or between the firewall and an external endpoint, if it's the second case then what is this external endpoint and is there a way to specify it (change it) ? 
 And is it normal to observe higher values of latency and jitter during active usage compared to idle time.

LuCar Toni · Accepted Answer

It is based on the Probing, you can configure in a Sd-wan profile. 
 Basically: if we send pings, and some pings are not returning = packet lost. 
 Pings also result in jitter and latency.

Prism · Answer

In some scenarios, it's normal to see higher latency/jitter values with active usage. (Mostly when your uplink is being fully utilized.) 
 This is mostly caused by bufferbloat.

Understanding SD-WAN performance

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