SLA is service level agreement when ticket is created overall time taken to resolve this incident is count as TAT and if ticket is resolved after TAT time then SLA is breach.,when ticket (incident) is created it comes under issue priority. There are 4 types of priority for tickets P1,P2,P3,P4. SLA for P1 & P2 is immediate action required and for P3 &P4 we can wait for POC reply, but ticket must be solve under TAT time for both cases.