A hydraulic drive system designed so that while maintaining intact a structure of a relief valve having a shockless function, the drive unit hydraulic drive system facilitates changing a driving pressure or braking pressure of a hydraulic swing motor and hence, changing a maximum driving torque or braking torque of the hydraulic swing motor. According to one aspect, a broker mechanism is established within a first container. The lines adjacent to the node-separated line include a protrusion portion protruding toward the cut-off portion of the separated line. Based on analysis of TCP path information andor sendreceive packet counts, loss of certain network connectivity can be inferred, which greatly improves the accuracy and responsiveness of detecting network connectivity losses. The first face includes a first axially arranged conical opening and a first positive locking cone forming an inlet valve. An antenna bus in each container, that is connected to a container ID tag reader, allows bus connector insertable antennas to be strategically placed for accommodating various asset packing densities.