Working With Model Items and Diagrams > Working with diagrams > Diagram types > Communication diagram
  
Communication diagram
For information about Object Interaction Modeling in Modeler, see Object interaction modeling overview.
A Communication Diagram models the structural dimension of a scenario by graphically illustrating the interactions between Actors and instances of Classes, Data Types, Interfaces and Signals. Communication Diagrams provide alternative representations of a Sequence Diagram, each one modeling a different execution thread (or \u201cscenario\u201d) through a use case by showing the flow or sequence of messages between associated objects. It is possible to have multiple Communication Diagrams for a single use case.
Communication Diagrams provide help with the architectural design of the system by providing a visual representation of the structure of object collaborations. They can be constructed very quickly, enabling experiments to be carried out with alternative designs based on different objects as collaborators and controllers, and with different messages passing between them.
You can create a Communication Diagram through the context menu of a Package: right-click the Package, point to New, point to UML, point to Behavior, and then click Communication Diagram. You can also create a Communication Diagram for an Event, Operation or Use Case: right-click the item, point to New, and then click Communication Diagram.
The following sections provide information about how a Communication Diagram is used in the model. For more information about an item, property or model part, click it.
Shows these dictionary items
Like most diagrams, a Communication Diagram can show variability items and relationships. See Overview of variability items and relationships on diagrams.
For most diagram symbols, you can change the presentation of the symbol through the Style view options (See Style view options - all diagrams ), and change the showing of Stereotypes and Tag Definitions through the Stereotypes view options (See Stereotypes view options for a symbol - all diagrams). When a symbol has additional view options for changing its presentation, this icon is shown - to see how the view options can change the presentation, click the icon.
Actor
Attribute (on Instances)
Instance
Comment
Constraint
Dependency
Event (instance of)
Operation (instance of)
Slot (on Instances)
These items (which are not documented in the reference topics) can also appear on a Communication Diagram:
• Frame Box - provides a way of adding a box or background image to the diagram.
• Note - provides a way of adding text to the diagram.
• Note Link - links a Constraint, Comment or Note to an item on the diagram.
Properties
A Communication Diagram has these properties:
• Description
• Full Name
• Last Changed By
• Last Changed On
• Name
• Page Reference
• Type
• Visibility
Owned by
Event
Model
Operation
Package
Use Case
Used in these parts of the model
Object Interaction Model
Can be linked to these dictionary items
Stereotype
* 
Like other diagrams in a Model, a Constraints Diagram can be linked to an Activity Partition, Comment, Frame Box, General Node, General Flow, General Flow Diagram Node, Constraint (applied), General Flow Diagram Flow or Swimlane.