Hello Wisam
These log messages indicate that there is an IP SLA configured and it is being triggered. When it is triggered, the state of the SLA is changed from UP to DOWN. This in turn triggers some other action (if it is configured) such as a change in routing for example. The triggering of the SLA is based on the threshold that has been configured. In order to determine what is actually happening to the network when the SLA is being triggered, examine the following:
your tracking configuration
your threshold percentage up/down configuration
The SLA configuration should not be the problem since it is configured in order to react when something changes. You should investigate what the SLA tracks as that has become unstable and has triggered this behaviour in the device. Take a look at this Cisco Documentaiton for more information about IP SLAs…
I hope this has been helpful!
Laz