A Transition Reduction Method for FSM of MANET Routing Protocol with Blacklist

In a MANET protocol, links between any two nodes are not always bi-directional because nodes can move around the network and their communication ranges are different. In order to detect unidirectional links, some mechanisms such as blacklist are introduced into the protocol. We call such a protocol unsymmetric. By node mobility over time, a unidirectional link can be changed to the bi-directional link and vice versa. Therefore, whenever directionality of any link changes, the protocol has to correctly detect whether the link is unidirect or bidirect. Even if a node receives the same kind of packet from its neighbor node, behavior of the node is different by the unidirectional or bi-directional link through which the node receives a packet. When testers perform conformance testing for these protocols, testers have to use FSM representing different behaviors of a node depending on directionality of the links. In general, the size of FSM grows exponentially along with increase of neighbors of a node. FSM for unsymmetric protocols is more complicated than that for symmetric protocols. Hence, the number of states and the number of transitions in FSM further increase for unsymmetric protocols. In this paper, we propose a new efficient method to solve this problem by treating both input and output as sets. The proposed method redefines a given FSM to an FSM in which the number of states and the number transitions are drastically reduced.