SysML 1.6 RTF Avatar
  1. OMG Issue

SYSML16 — Clarify port usage patterns

  • Key: SYSML16-254
  • Status: closed  
  • Source: GfSE e.V. ( Mr. Robert Karban)
  • Summary:

    The following sentence is misleading:

    9.1.3 Proxy Ports and Full Ports

    'SysML identifies two usage patterns for ports, one where ports act as proxies for their owning blocks
    or its internal parts (proxy ports), and another where ports specify separate elements of the system (full ports).'

    There are in fact at least three usage patterns: normal (UML) ports, full, and proxy.

    There is a prevailing misunderstanding that normal ports should not be used at all in SysML.
    (There are dozens of places in the spec stating that normal ports still can be used.)

    This has lead to recent tool vendor errors not offering
    a basic ports compartment, although it is clearly specified and even shown in some figures.

    A single word might improve things:

    'SysML identifies two additional usage patterns for ports …’

    Or more verbosely:

    'SysML identifies two more specific usage patterns for ports in addition to standard ports …

  • Reported: SysML 1.5 — Sun, 5 Mar 2017 19:33 GMT
  • Disposition: Closed; No Change — SysML 1.6
  • Disposition Summary:

    All usage kinds are defined

    The two "usage patterns" specified by the referenced text actually described two mutually exclusive options. A "third" option, if any will be not to choose between this two alternatives. This is specified by applying none of those SysML stereotype or, in other words, to use the UML concept of port natively.

    So, I would not be correct to tell about "additional usage patterns".

    In addition there is this sentence at the end of the first paragraph of section 9.1.3: "Ports that are not specified as proxy or full are simply called “ports.", then in the next paragraph : "Proxy and full ports support the capabilities of ports in general, but these capabilities are also available on ports that are not declared as proxy or full. Modelers can choose between
    proxy or full ports at any time in the development lifecycle, or not at all, depending on their methodology"

  • Updated: Mon, 1 Apr 2019 18:17 GMT