IP SLA operations are tools on cisco devices that let you analyse and troubleshoot networks. They can be used to measure things like latency, packet response times and broadband speeds.
The frequency command lets you define the rate (in seconds) in which an operation is repeated. By default this is 60 seconds. For example the commands below could be used to make the Router send a ping every thirty seconds to Google’s DNS for 10 minutes..
ip sla 1
icmp-echo 8.8.8.8
frequency 30
exit
ip sla schedule 1 life 600 start-time now
The first part of that is the ip sla [OPERATION-NUMBER]. The Operation number is just an identifier / group of operations that will be run at the same frequency. You can have multiple operation numbers for different routines.
Once it has been set up you run the ip sla [OPERATION-NUMBER] life [HOW MANY SECONDS YOU’D LIKE THIS TO GO ON FOR / forever] start-time [now / after hh:mm:ss]