This paper describes a methodology and a case study in formal verification. The case study is the protocol, a member of the adaptation layer whose main role is to perform a reliable data transfer over an unreliable communication medium. The methodology involves: (1) a state-space exploration for initial debugging; (2) a partial-order abstraction that preserves the properties of interest; and (3) a compositional verification of the properties at the abstract level using the theorem prover. Steps (2) and (3) guarantee that the properties still hold on the whole (composed, concrete) system as well. The value of the approach lies in adapting and integrating several formal techniques for verifying a real case study.