US Patent 9246805 Communication station, communication control program, and communication network system

There is provided with a communication station including: a receiving unit, a determining unit, a transmitting unit and a reachability testing unit wherein the receiving unit receives a packet from a network in which a plurality of communication stations are interconnected, the determining unit determines whether the receiving unit receives a first packet in which a transmission source address is an address of a first communication station, the transmitting unit transmits a reply request packet to request a reply to the first communication station, and the reachability testing unit omits for the transmitting unit to transmit the reply request packet when the first packet is received before the transmitting unit transmits the reply request packet.