Node Instance   A node instance represents a distinct instance of a node. It is an actual instance of a resource that carries out the work of the system. It has unique identity as well as attribute values, which determine its state at any point in time. A node instance can exhibit behavior, but only as a result of being an instance of a node. A node instance is an instance of one (and only one) node.

Explanation

Whereas a node represents the type of physical device a node instance represents an actual instance of the node. Typically in a computer system its name will be the name written on the front of the machine and you can touch the machine. Some confusion arises here because there has been a tendency to model nodes rather than node instances. A manufacturer would typically speak of nodes whereas an organization would more typically speak of node instances. The device that is listed in a catalogue is usually a node, whereas when you procure the device, what is delivered is an instance. Node instances that are a part of a business system represent actual instances that can be touched.

Related Entries

Node  More General,  Graphically Similar A node is related to a node instance because it is the classifier from which the instance is derived. A node represents a description of the set of things, whereas the node instance represents a specific element from the set.

Component Instance  Used Together A component instance is related to a node instance in the sense that component instances are said to reside on node instances. Component instances are physical things that need to reside on a node, which behaves like a platform for their expression.