A new test sequence generation method is proposed for testing the conformance of a protocol implementation to its data portion modeled by an Extended Finite State Machine (EFSM), which is represented by a Data Flow Digraph. All-Use and IO-df- chain are two important criteria for selecting paths from the Data Flow Digraph to generate a test sequence which traces the data flow property, but it is a tedious process to select a path which satisfies the criteria while guaranteeing that the generated test sequence is executable (i.e., one that has feasible parameter values). In this paper, we propose a four-step method for generating the executable test sequence. The first step is a manual process, while the other three steps involves automatic as well as optimizing algorithms. The first step involves the manual generation of a Behavior Machine Digraph from the Data Flow Digraph by embedding certain (but not all) parameter values so that every path of the new digraph is executable. Unlike the FSM for circuits, the size of the Data Flow Digraphs for real protocols can be managed test experts. In the second step, executable test paths which trace every association defined by each criterion are generated from the Behavior Machine Digraph. In the third step, the Behavior Machine Digraph is embedded with these test paths so as to construct the SelectUse and SelectIO Digraphs. Finally, the Selecting Chinese Postman Tours of the two digraphs are used to generate the executable test sequences that satisfy the All-Use and IO-df-chain criteria.