Abstract
The paper compares and contrasts various methods presently available for specification, validation and verification, with emphasis on verification. We describe an application of formal methods to protocol specification, validation, and verification, using an actual protocol as an example. We use a process algebra to build models of an OSI protocol and test these models using a model checker. Model checking allows us to verify large and complex models and use formal methods as practical solutions. We also show an example with an automated theorem prover.