Modeling the communication structure of the application with constraint links

The topology editor includes a variety of elements that can help you plan the way that the components of your application and infrastructure communicate.

About this task

Planning the communication structure in a topology involves adding links, constraint links, constraints, and other elements to units in a logical or operational model. For information on logical or operational models, see Modeling the operational or logical layout of the application. When you add these elements to your high-level models, the topology editor enforces the links and constraints on the more specific physical and deployment models and down the hosting stack.

Procedure

Add application communication constraint links between the components of the application that must communicate. If you have imported UML elements into the topology, you can use UML interactions to create the constraint links. See Using UML interactions as constraints in topologies.
Using the warnings and resolutions on the infrastructure units, add network communication constraint links between the infrastructure units that must communicate. An application communication constraint link between two units often requires a corresponding network communication constraint link between units in their hosting stack or between units to which the units are realized.
Identify the units that must be hosted on the same computer system or must be hosted on separate computer systems and create collocation or anti-collocation constraint links between those units.
Add any other requirements, constraints, or other topology elements that specify the structural requirements of the application. For example, you can add an attribute propagation constraint to a unit to ensure that the unit to which it is realized has a specific attribute value. You can add a stereotype to a unit to ensure that it is realized only to units with that stereotype. You can add deferred hosting constraint links to indicate that the realization targets of two units must be in the same hosting stack.
Import the logical model topology into a physical model topology and create realization links from units in the logical model to units in the physical model. Because of the realization links, the topology editor enforces the constraints on the units in the physical model. For example, if you create realization links from nodes in the logical model to computer systems in the physical model, the topology editor might prompt you to create network communication constraints between the operating systems in those computer system stacks.