Message Sequence Chart
Encyclopedia
Specification and Description Language
Specification and Description Language is a specification language targeted at the unambiguous specification and description of the behaviour of reactive and distributed systems.- Overview :It is defined by the ITU-T...
family very similar to UML
Unified Modeling Language
Unified Modeling Language is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created, by the Object Management Group...
's sequence diagram
Sequence diagram
A sequence diagram in Unified Modeling Language is a kind of interaction diagram that shows how processes operate with one another and in what order. It is a construct of a Message Sequence Chart....
, standardized by the International Telecommunication Union
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...
.
The main area of application for Message Sequence Charts is as for communication behaviour in real-time systems
Real-time computing
In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...
, more specifically telecommunication Electronic Switching System
Electronic switching system
In telecommunications, an electronic switching system is:* A telephone exchange based on the principles of time-division multiplexing of digitized analog signals. An electronic switching system digitizes analog signals from subscriber loops, and interconnects them by assigning the digitized...
s.
History
The first version of the MSC standard was released in 1992.The 1996 version added references, ordering and inlining
Inline expansion
In computing, inline expansion, or inlining, is a manual or compiler optimization that replaces a function call site with the body of the callee. This optimization may improve time and space usage at runtime, at the possible cost of increasing the final size of the program In computing, inline...
expressions concepts, and introduced HMSC (High-level Message Sequence Charts), which are the MSC way of expressing State diagram
State diagram
A state diagram is a type of diagram used in computer science and related fields to describe the behavior of systems. State diagrams require that the system described is composed of a finite number of states; sometimes, this is indeed the case, while at other times this is a reasonable abstraction...
s.
The latest MSC 2000 version added object orientation, refined the use of data and time in diagrams, and added the concept of remote method calls.
Comparison to UML
It has been said that MSC has been considered as a candidate for the interaction diagrams in UML.However, proponents of MSC such as Ericsson
Ericsson
Ericsson , one of Sweden's largest companies, is a provider of telecommunication and data communication systems, and related services, covering a range of technologies, including especially mobile networks...
think that MSC is better than UML 2.0
Unified Modeling Language
Unified Modeling Language is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created, by the Object Management Group...
for modelling large or complex systems.
Live Sequence Charts
David HarelDavid Harel
David Harel is a professor of computer science at the Weizmann Institute of Science in Israel. Born in London, England, he was Dean of the Faculty of Mathematics and Computer Science at the institute for seven years.-Biography:...
thinks that MSC still has several shortcomings such as:
- MSC propose a weak partial orderingPartially ordered setIn mathematics, especially order theory, a partially ordered set formalizes and generalizes the intuitive concept of an ordering, sequencing, or arrangement of the elements of a set. A poset consists of a set together with a binary relation that indicates that, for certain pairs of elements in the...
semantics that makes it impossible to capture some behavioral requirements, - The relationship between the MSC requirements and the executable specification is not clear.
To address what he sees as weaknesses in the MSC model, David Harel proposed an extension on the MSC standard called LSC (Live Sequence Charts).
Tools
- MSC Tracer Free tracing tool based on PragmaDev Real Time Developer Studio
- MscGenMscGenMscgen is a software tool for drawing message sequence charts from a simple to manage text-based source file. Rendered charts can be output in PNG, SVG and PostScript, with hyperlink information in ismap format...
- Automatic generation of diagrams based on text descriptions of the messages. - Web-based MSC Generator
- Msc2Svg - Generates charts as SVG from a simple text description file
- EventStudio - Message sequence chart generation tool
- LTSA -- Supports the drawing and subsequent automated verificationFormal verificationIn the context of hardware and software systems, formal verification is the act of proving or disproving the correctness of intended algorithms underlying a system with respect to a certain formal specification or property, using formal methods of mathematics .- Usage :Formal verification can be...
of message sequence charts. - Sequence Chart Studio - Extends Microsoft VisioMicrosoft VisioMicrosoft Visio , formerly known as Microsoft Office Visio, is a commercial diagramming program for Microsoft Windows that uses vector graphics to create diagrams.- Features :...
to draw and verify Z.120 compliant sequence charts. - Trace2UML - Tool for drawing and recording sequence charts.
- MSC Latex package - a LaTeXLaTeXLaTeX is a document markup language and document preparation system for the TeX typesetting program. Within the typesetting system, its name is styled as . The term LaTeX refers only to the language in which documents are written, not to the editor used to write those documents. In order to...
package for creating message sequence charts.
External links
- ITU-T Recommendation Z.120 Message Sequence Chart (MSC)
- Michel Reniers: “Message Sequence Charts -- Syntax and Semantics”, PhD Thesis, Eindhoven University of TechnologyEindhoven University of TechnologyThe ' is a university of technology located in Eindhoven, Netherlands. The motto of the university is: Mens agitat molem . The university was the second of its kind in the Netherlands, only Delft University of Technology existed previously. Until mid-1980 it was known as the...
, 1999