Communication between the Console and OMS, and between OMS and the agent(s), is via HTTP, thus making it easy to deploy OEM within firewall-protected environments. Secure Sockets Layer (SSL) can be enabled to allow secure communication between tiers.
OEM Database Control is installed at the time you install the base Oracle software. You can choose to install it into the same ORACLE_HOME location, or give it its own ORACLE_HOME location. If you wish to install OEM Grid Control, you need to do that as a separate operation.
If you create the database via the Oracle Database Configuration Assistant (DBCA), then OEM Database Control will be installed and preconfigured along with the database. If you are manually creating the database, then you will want to run a script to install OEM Database Control in the database. The name of this script at the time of this writing is DBConsole.pm, and it appears to be a pearl on the Windows NT platform. Both the name of the script and the type of script may differ on various platforms (and versions of Oracle Database 10g), so check the OEM documentation to make sure which script you need to run on your platform.
An Apache HTTP server is included with the database server so you can start working with the OEM out of the box, thus requiring zero startup time. The Oracle Enterprise Manager repository, job, and event subsystems are now configured automatically, eliminating the need for manual setup.
OEM can be deployed in a number of ways, depending on the complexity of your system and the options that you want. If you create your databases using the DBCA, you are given an option to determine whether you wish to use Grid Control (shown in the figure below as central management) or Database Control (shown as local management), as shown in Figure 9-2.
Let's look at these deployment options in a bit more detail next.
The screens you see in your version of Oracle Database 10g may be somewhat different than those shown in the figures in this chapter. The look and feel of the OEM may change significantly between minor releases of the software.