A new class is declared as a subclass of an existing ICIM class. The key is to determine which class should be the parent class. This determination is based on several factors:
How you want to search and report on the new class
Functional similarities to existing elements in topology
The events, attributes, and relationships the new class needs to inherit
For example, suppose a class that represents a printer needs to be added to the model. A printer is a physical element, similar to a router, switch, or host. Therefore, the printer class can be defined as a subclass of UnitaryComputerSystem, which is the parent class of routers, switches, and hosts. The printer class inherits all of the attributes, relationships, and events of the UnitaryComputerClass class.Note:
The IP Manager counts the instances of the ICIM_UnitaryComputerSystem. If this is a problem for you, you can inherit from either ICIM_System or ICIM_ComputerSystem. However, if you inherit from either ICIM_System or ICIM_ComputerSystem you will have to add your new class into the appropriate dxa to transfer the topology to the Global Manager. Chapter 3, “Exercise 2 - Adding an Attribute to the Router Class,” provides information about adding a class and its associated attributes to dxa files.