Response time: from call taking till ticket open

Solution time: it is time limitation to give customer solution

Problem severity	Fault description	Response time	Solution time
S1	System down  Restart everyday  More than 50% of users and trunks out of service  No CDR for Hotel and Carrier Key application system down Customer’s VIP out of service No dial tone	15 mins	1 day
S2	Restart once one week  One shelf out of service  30% of trunks out of service  No CDR for normal customer  Part of application system down	2 hrs	2 days
S3	Standby out of service Operation terminal or Attendant console out of service Module out of service Key function lost	4 hrs	1 week
S4	Telephone out of service Can’t use normal function Can’t change or configure subscriber and trunk	8 hrs	2 weeks
S5	Other minor fault	24 hrs	1 month