A connection object specifies which domain controllers replicate with which other domain controllers, how often, and which naming contexts are involved. Unlike sites, subnets, and site links, which you generally need to manually configure, connection objects are generally managed by the domain controllers themselves. The idea is that you should logically construct the site topology with good definitions for sites, subnets, and site links, and Active Directory will be able to figure out the best way to interconnect the actual domain controllers within and between the sites.
It is occasionally not possible to allow AD to manage all of these connections, but it is a very good goal to work toward, and you should endeavor not to modify or supplement connection objects unless you have no other choice. Earlier versions of Active Directory were not able to properly load balance replication connections between domain controllers, so a domain controller in a hub site could become overwhelmed with replication traffic from spoke domain controllers.
This scenario often caused administrators to opt to attempt to manage replication connections manually or with the Active Directory Load Balancing (ADLB) tool. Fortunately, beginning with Windows Server 2008, Active Directory gained the ability to automatically load balance replication connection to read-only domain controllers (RODCs).
Windows Server 2008 R2 extended this capability to load balancing of replication connections with all types of domain controllers.
You can view connection objects with AD Sites and Services as well as the Get- ADReplicationConnection cmdlet. Both the MMC snap-in and Windows PowerShell enable you to make changes to connection objects, and AD Sites and Services allows you to create new connection objects.
When you manually create or modify a connection object, Active Directory will no longer automatically manage that connection object.
With this in mind, you should endeavor not to manually edit or create connection objects and instead maintain an accurate site topology that the KCC can use to build and maintain the correct connection object topology.
If the name of the connection object in the MMC does not display as <automatically generated> that means that Active Directory is not managing the connection object.