Site boundaries should not be configured in such a way as to create an overlapping boundary situation. Site boundaries should always be deleted from the site to be decommissioned, and the site boundaries changes should be allowed to replicate throughout the hierarchy before adding site boundaries to the new Configuration Manager 2007 site.

When preparing to begin the client upgrade and reassignment process, clients must not attempt to contact any SMS 2003 site systems still in operation. Before beginning the client upgrade process, ensure that SMS 2003 site systems are no longer published to Active Directory or still registered in WINS or DNS.

Distribution points need to be updated at the new site, and distribution points from the old site need to be removed from existing package properties.

Custom computer collections and software distribution objects are replicated from Configuration Manager 2007 parent sites to their child sites. To migrate custom collections and software distribution objects from an existing SMS 2003 site to a new Configuration Manager 2007 site by using the side-by-side upgrade method, you first must upgrade the existing SMS 2003 site to Configuration Manager 2007.

Before upgrading an SMS 2003 site that has the Inventory Tool for Microsoft Updates (ITMU) installed and that will be configured as the parent site for a new Configuration Manager site, consider the following factors:

• If you will continue to use ITMU to manage software updates for SMS 2003 clients assigned to the new Configuration Manager site, the SMS 2003 ITMU must be upgraded during the site upgrade process. For more information about upgrading ITMU during the site upgrade process, see About the Inventory Tool for Microsoft Updates.
  
  
• After successfully upgrading the SMS 2003 site and ITMU, a software update point must be installed and configured to synchronize updates with Microsoft Update. After the software update point has successfully synchronized with Microsoft Update, the upgraded site can be configured as the parent site for a new Configuration Manager 2007 site. For more information about installing a software update point, see How to Create and Configure an Active Software Update Point.
  
  

If ITMU will not be used or has been uninstalled from the SMS 2003 site to be upgraded, the following factors should be considered:

• All existing ITMU software update packages and advertisements must be deleted before beginning the upgrade process.
  
  
• Software update point installation and synchronization is not required as part of the upgrade process.
  
  

After the existing site has been upgraded, install the new Configuration Manager 2007 site and attach it as a child site to the previously upgraded site.

When all of the required objects have replicated down to the new site, and if the newly installed Configuration Manager 2007 site will become the central site for the hierarchy, the parent-child site relationship can be broken and the original site can be decommissioned.

Because the site codes will be different, replicated collection and software distribution objects will have different unique IDs than objects created by the new Configuration Manager 2007 site.

Note
Even though the unique IDs for replicated objects will be different than new objects created at the new Configuration Manager 2007 site, this does not affect collection evaluation or client software distribution operations at the new site.

Because client data flows up the site hierarchy, you can retain client historical data during the upgrade process by attaching the SMS 2003 site as a child site of the new Configuration Manager 2007 site. After client data has been replicated to the new Configuration Manager 2007 site, the parent-child site connection can be broken.

Client management must be maintained throughout the upgrade process. To ensure that clients are always assigned to a site and properly managed, you should maintain their existing SMS 2003 site assignment until the Configuration Manager 2007 site is fully functional. Reassigning and upgrading the SMS 2003 clients to Configuration Manager 2007 clients can be accomplished using client installation methods that do not require site boundary assignment. For example, you can use software distribution methods from the SMS 2003 site to simultaneously upgrade and reassign existing clients to the new Configuration Manager 2007 site. Another option is to enable a discovery method at the new Configuration Manager 2007 site (without assigning boundaries to the site itself) and use the client push installation method to upgrade and reassign clients.