Response Times

Hi, would someone please clarify how exactly the response times are calculated for each type of monitoring in Applications Manager? What is the process involved?

From what I've read, for Database servers the response time is the time taken by the Applications Manager to establish a JDBC connection to that database.

For Services, the response time is the time taken to connect to the port, execute the given command and search the string.

Could someone please provide the process involved for calculating the response times of Application Servers (Tomcat) and URLs (time for the page to completely load?)

All help would be appreciated.
Thanks,
Jaya Sritharan