Webel Radio Net: 'message' SysML Package Diagram with Message block "packet" and '$msg' String

Gallery
Tutorial
[TRAIL] SysMLv1: The Webel Radio Net port-based messaging example model in Cameo Systems Modeler and Cameo Simulation Toolkit
Section
Webel Radio Net: Model overview, exchange items, and Ports
Topic level
BASIC
UML keywords
Signal
Keywords
Slide kind
SysML Package Diagram
Before we inspect the radio message system, we inspect the Message block "packet" that radio transmissions may carry.
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There is no Association from RadioRequestForward(RFF) to Message for attribute msg:Message because:
SysMLv1: Cameo Simulation Toolkit: GOTCHA: Do not use Associations with Signal attributes, they will become null when fed as argument values for Parameters of 'effect' Behaviors of Transitions

A Message block is a very simple model of transmitted data or information. It is not specified here whether over analog or digital or how stored, and specific encryption is out-of-scope.

In a real radio net transmissions could carry not just text messages but voice, images, data, etc. For the sake of this simulation just a text String is used, denoted $msg.

In Webel models a '$' prefix in a value or parameter name is often used to indicate a String (or an Enumeration) such as here for $msg to distinguish it from msg used for a Message object. Care must be taken, however, when using scripting languages that do not permit '$' in variable names; Groovy handles a '$' in variables names just fine.

A Message object acts as the "packet" carried by a RadioMessage Signal, as shown for a RadioRequestForward(RFF) Signal, which is a request from a Participating Station (PS) to the Net Control Station (NCS) to forward the contained message to another Participating Station (PS).

Each Message object is identified by a UUID, which may be used for lookup in net session logs.

The 'message' Package also contains some supporting utility Behaviors, such as an Activity createMessage and Goovy-based OpaqueBehaviors for interrogating a list of Message items against a UUID.

Up next
Webel Radio Net: 'radio' SysML Package Diagram with high level view of Port types for 'Radio' Signals
Notes
[ASSERTION, MODELLING, PATTERN]{STRONG} Webel: SysML: Heard of "follow the money"? In MBSE we "follow the flows"! Identify requests, data packets, messages, signals early on and use ItemFlow as often as you can wherever you can! Adopt a signal processing mindset throughout (systems thinking).
[GOTCHA, ISSUE, LIMITATION, TOOL, WARNING]{INFORMATIVE} SysMLv1: Cameo Simulation Toolkit: GOTCHA: Do not use Associations with Signal attributes, they will become null when fed as argument values for Parameters of 'effect' Behaviors of Transitions
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