<specification, protocol> (FDT) A formal method for
developing telecomunications services and protocols. FDTs
range from abstract to implementation-oriented descriptions.
All FDTs offer the means for producing unambiguous
descriptions of OSI services and protocols in a more
precise and comprehensive way than natural language
descriptions. They provide a foundation for analysis and
verification of a description. The target of analysis and
verification may vary from abstract properties to concrete
properties. Natural language descriptions remain an essential
adjunct to formal description, enabling an unfarmiliar reader
to gain rapid insight into the structure and function of
services and protocols.
Examples of FDTs are LOTOS, Z, SDL, and Estelle.
[ISO/IEC DTR10167: "Guidelines for the application of
Estelle, LOTOS and SDL"].
