TTCN
Work on Tree and Tabular Combined Notation (TTCN) first started in 1984 in as part of the work on OSI conformance testing methodology and framework. Since then TTCN was widely used for describing protocol conformance test suites in standard organizations such as ITU-T, ISO/IEC, ATM Forum, and ETSI and in industries. The main characteristics of TTCN that contributed to its wide acceptance are that:
- its Tabular Notation allowed its user to describe easily and naturally in a tree form all possible scenarios of stimulus and various reactions to it between the tester and the Implementation Under Test (IUT),
- its verdict system was designed such that to facilitate conformance judgment on the test result agrees against the test purpose, and
- it provides a mechanism to describe appropriate constraints on received messages so that conformance of the received messages can be mechanically evaluated against the test purpose.
TTCN-2
The first edition of TTCN was not suitably designed to describe the concurrent behavior within the tester or within IUT or between them and the need for an extension to deal with concurrent behavior efficiently was soon recognized. In the process of extension, in addition to concurrency mechanism, the concepts of module and package were newly introduced to TTCN to increase reusability and to achieve encapsulation. Also manipulation of ASN.1 encoding was made possible beyond simple syntax declaration. The TTCN extended in this way was adopted as TTCN version 2 (TTCN-2) in 1998.
TTCN-3
In spite of the improvements in TTCN-2, TTCN was designed from the beginning with OSI-based protocol conformance testing in mind and even TTCN-2 was not adequate for various kinds of testing such as interoperability testing, robustness testing, regression testing, system testing and integration testing or for various emerging testing application areas such as mobile protocol, Internet protocol, service testing, module testing, CORBA-based platform testing and API testing. Therefore a more flexible and powerful test description language was called for. In order to meet such a need ETSI started working on a new version of TTCN in 1998 and completed it in October 2000.
TTCN-3 retained the proven features of TTCN-2 but was designed to provide the new features listed above. A single most visible difference is that the previous versions adopted as the main description notation the Tabular Notation and its textual counterpart a machine-processible language for translation to programs whereas in TTCN-3 the usual programming language-like notation is adopted as the core language with the Tabular Notation and MSC as presentation languages.
Comparing it with TTCN-2, TTCN-3 has the following improvements
- well-defined syntax, interchange format and static semantics and
- precise execution algorithm (operational semantics).
More information:
- The evolution of TTCN
- TTCN – Wikipedia
- Why use TTCN-3?
