This topic introduces the necessary terminology for creating a topology that involves servers that are outside of the WebSphere Extended Deployment and WebSphere Extended Deployment cells.
Unmanaged machines. WebSphere Application Server stores information about unmanaged machines in the configuration files. Unmanaged machines can have custom properties. Pure external machines and foreign machines might be unmanaged, but also might not have information stored in the configuration files. Machines that do not have any information stored in the configuration files are neither managed or unmanaged.
A generic server cluster is a collection of transport end points that can be used as a target for an ODR routing rule. Generic server clusters are not collections of generic servers. Servers and nodes are inferred from the generic server cluster end points and properties. The inferred servers can be foreign or generic servers. Generic server cluster end points can have a custom property that identifies its node, or the node is identified by the host name from the end point. The node for a generic server cluster can be any type of node. See Routing requests to external nodes with generic server clusters for more information about configuring generic server clusters.
An external cluster is used for foreign and generic servers that are not referenced by generic server clusters. For example, an external cluster might reference database servers. External clusters cannot be a target, and cannot contain target servers. Servers that belong to an external cluster can run on any type of machine. You must explicitly configure the server placement and speeds of the unmonitored nodes in the ODR cell using the external.placement custom property.