Database of Case Studies Achieved Using CADP

Matrix Switch

Organisation: LGI/IMAG (Grenoble, FRANCE)

Method: LOTOS

Tools used: CADP (Construction and Analysis of Distributed Processes)

Domain: Telephony

Period: 1990

Size: 110 lines of LOTOS

Description: The study focuses on the matrix switch problem that has been put forward during the FORTE'88 conference in Stirling (Scotland, UK).

It is a real problem in telephony to define the combination of a concentrator, switch block, and expander switch, in which many routes through the switch are simultaneously active. There is also the issue of describing connections from many ports to many ports and of defining simultaneously active routes. The system under study contains two components: a square ``matrix switch'' and a ``concentrator''.

Conclusions: A ``reasonable'' LOTOS specification style was proposed and illustrated step by step on the matrix switch problem. This style is based upon communicating automata for the control part (using only static control structures and avoiding dynamic control features, such as recursion in LOTOS parallel composition, as well as recursion on the left of the enabling and disabling operators) and constructor discipline for the data part (still making plain use of dynamically-allocated data structures to express dynamic aspects of the problem).

Publications: [Garavel-Rodriguez-90] Hubert Garavel and Carlos Rodrìguez. An Example of LOTOS Specification: the Matrix Switch Problem. Rapport SPECTRE, C22, Laboratoire de Génie Informatique - Institut IMAG, Grenoble, June 1990
Available on-line from:
or from our FTP site in PDF or PostScript

Hubert Garavel
BP 53X
38041 GRENOBLE cedex

Further remarks: This case-study, amongst others, is described on the CADP Web site:

Last modified: Fri Feb 19 09:12:04 2016.

Back to the CADP case studies page