Dependency associations establish the relationships between objects that rely on one another. The Core Model provides for the following types of dependencies:
Functional--the dependent object cannot function without the object on which it depends
Existence--the dependent object cannot exist without the object on which it depends
The following types of dependencies are included in the Core Model.
Table A-3 Core Model Dependencies
Dependency Association |
Description |
HostedService |
An association between a Service and the System on which the functionality resides. The cardinality of this association is one-to-many. A System may host many Services. Services are weak with respect to their hosting System. Generally speaking, a Service is hosted on the System where the LogicalDevices or SoftwareFeatures that implement the Service are located. The model does not represent Services hosted across multiple systems. This is modeled as an ApplicationSystem that acts as an aggregation point for Services that are each located on a single host. |
HostedAccessPoint |
An association between a ServiceAccessPoint (SAP) and the System on which it is provided. The cardinality of this association is one-to-many and is weak with respect to the System. Each System may host many SAPs. A feature of the model is that the access point of a service can be located on the same or a different host from the system to which the service provides access. This allows the model to depict both distributed systems (an ApplicationSystem with component Service on multiple hosts) and distributed access (a Service with access points hosted on other systems). |
ServiceSAPDependency |
An association between a Service and a ServiceAccessPoint indicating that the referenced SAP is required for the Service to provide its functionality. |
SAPSAPDependency |
An association between a SAP and another SAP indicating that the latter is required in order for the former to utilize or connect with its Service. |
ServiceAccessBySAP |
An association that identifies the access points for a Service. For example, a printer may be accessed by Netware, Apple Macintosh, or Windows ServiceAccessPoints, potentially hosted on different Systems. |