Brief description of each Site System Role

Site System Role	Description	Required?
Site server	The role assigned to the server on which Configuration Manager 2007 Setup has been run successfully.	Yes. Every site must have exactly one site server role.
Site database server	The role assigned to the computer running a supported version of Microsoft SQL Server and hosting the Configuration Manager 2007 site database. You can use only Microsoft SQL Server, Standard or Enterprise Edition, to host the site database. SQL Server Express editions are not supported for hosting the site database.	Every primary site requires a site database server role, but secondary sites do not require them.
Configuration Manager console	Any computer running the Configuration Manager console.	No. The Configuration Manager console is automatically installed by default on primary site servers during Setup. You can install additional Configuration Manager consoles on remote computers—for example, the workstation of the Configuration Manager administrator. However, some organizations write their own user interface using the Configuration Manager software developer kit (SDK) and never use the Configuration Manager console.
SMS Provider computer	The Configuration Manager console does not access the database directly, but instead uses Windows Management Instrumentation (WMI) as an intermediary layer. The SMS Provider is the WMI Provider for Configuration Manager.	Yes, for primary sites. When you install a primary site, you select which computer will host the SMS Provider—usually, it's the site server or the site database server.
Component server	Any computer hosting a Configuration Manager 2007 site role that requires installing special Configuration Manager 2007 services.	The only site system role that does not require the installation of a special Configuration Manager 2007 service is the distribution point.
Distribution point	A site system role that stores packages for clients to install.	Required for the following features: software distribution, software updates, and advertised task sequences used in operating system deployment.
Fallback status point	A site system role that gathers state messages from clients that cannot install properly, cannot assign to a Configuration Manager 2007 site, or cannot communicate securely with their assigned management point.	Not required, but very helpful to troubleshoot issues with clients.
Management point	The site system role that serves as the primary point of contact between Configuration Manager 2007 clients and the Configuration Manager 2007 site server.	Every site with intranet clients must have one default management point, though the default management point might be a cluster of several site systems configured as management points.
PXE service point	A site system role that has been configured to respond to and initiate operating system deployments from computers whose network interface card is configured to allow PXE boot requests.	Required only for operating system deployment using PXE boot requests.
Reporting point	A site system role hosts the Report Viewer component for Web-based reporting functionality.	Required only to use the reporting feature. Reports are often helpful when diagnosing client issues.
Server locator point	A site system role that locates management points for Configuration Manager 2007 clients.	Required for some client deployment scenarios.
Software update point	A site system role assigned to a computer running Microsoft Windows Server Update Services (WSUS).	Required only for the software update feature.
State migration point	A site system role that stores user state data while a computer is being migrated to a new operating system.	Required for operating system deployment when migrating user state.
System Health Validator point	The site system role assigned to a computer running Network Policy Service.	Required only for the Configuration Manager 2007 Network Access Protection feature.