We present a two step design of the just-in-time (JIT) signaling scheme running over a core. dWDM network which utilizes optical burst switches (OBS). In the first step, we apply an eight-tuple extended finite state machine (EFSM) model to formally specify the protocol. Using the EFSM model, we define the communication between a source client node and a destination client node through an ingress and an intermediate switch. The communication between the EFSMs is handled through messages. In the second step, we generate unique input-output sequences. We work on on-the-fly unicast connection over a prototype testbed.