How is DNS Response Time attribute calculated by the ITCAM monitoring agent for Microsoft Active Directory?
Monitoring agent for Microsoft Active Directory reports DNS response time as the time in milliseconds taken by DNS Server to respond to a single query. The agent derives this value from the DNS server performance counter (Total Response Sent/sec).
Performance counter "Total Response Sent/sec" is the average number of responses sent by the DNS server in each second.
Following formula is used by the agent to calculate DNS Response Time:
DNS Response Time (in milliseconds)= (1000 + rounding factor)/ (Total Response Sent/sec)
1. Calculate rounding factor as 1/2 the Total Response Sent/sec.
2. Add this rounding factor to 1000 (1 second is equal to 1000 milliseconds) and divide by performance counter "Total Response Sent/sec".