Simple definition
IP SLA is an active measurement mechanism available on some network devices to test path availability or quality.
Technical definition
An IP SLA probe periodically generates test traffic, such as ICMP, TCP, UDP, HTTP, or DNS depending on device capabilities, and records metrics such as reachability, latency, or jitter.
How it works / role
The device runs the configured operation toward a target, records the result, and can associate it with a tracking object. That result can feed monitoring or influence routing decisions, for example by withdrawing a preferred route when the target is no longer reachable.
What is it used for?
Actively monitor a service or path and trigger an action when availability or quality changes.
Practical example
A router periodically probes a remote IP address; if the tests fail, a tracking mechanism removes the primary route so a backup route can take over.
Common issues
- Probe target is filtered even though the real path still works
- Probe does not represent the actual user service
- Threshold is too sensitive and causes frequent failovers
- IP SLA result is linked to the wrong tracking object
Key takeaway: IP SLA provides active measurements; the target and probe type must represent the service that actually matters.