If there are multiple applications hosted on the same application server, the GSLB should probe these applications to see if the applications are responding or not. If an application is not responding, the user must be directed to the server on which the application is UP. Also, if one of the applications is DOWN, then the server should not be marked DOWN, because the other applications are UP.
In the following example, multiple applications (HTTPS) are hosted on one server in each GSLB site and hence all these applications resolve to one IP address of the respective site.
Using the GSLB service groups, you can have the same server with an IP address and port bound to multiple service groups where each service group represents a different application.
An application specific monitor is bound to the service groups that marks the service group as DOWN if the application is DOWN. Thus, whenever an application is DOWN, only that application is taken out from the setup and not the server.