SYSML17 — SysML: Protocol State Machines needed

The current document eliminates Protocol State Machines on the grounds of simplification. See Section 13

However, this leaves a hole in the capabilities of SysML. Currently, SysML supports UML interfaces (provided and required), which can’t have state machines to define them.

It is an important part of designing systems interfaces (SE terminology) to define the details of the (UML/SysML) Interfaces. These details include the allowed ordering of messages. As we are not allowed to use behavior state machines and the standard solution, that of, protocol state machines are not included, we can’t properly do interface engineering within SysML

If some other solution/work-around is proposed (which I don’t recommend) the explanation of how to accomplish this should be in the spec.

Proposal: Protocol State Machines deferred to SysML v2

Table 4-1 excludes the model element ProtocolStatemachines from the UML4SysML subset. The impact of introducing ProtocolStatemachines in SysML v1 is too big for v1 and out of scope for an RTF.

The need for ProtocolStatemachines was already sent to the team working on SysML v2. They identified a high coverage with the SysML v2 RFP requirement INF 1.07.1.