A network may determine the location of network nodes and tracked assets and make location-based decisions. An example checkout stand includes a housing including a first and a second end, a conveyor for transporting items from the first end to the second end, a bagging station at the second end, a base portion between the conveyor and the bagging station, a first tower portion on the base portion, and a second tower portion on the base station separated from the first tower portion by a gap. The active and inactive PHB’s provide information on how to route, transport, and process packets belonging to a session. The developing agent cartridges are attacheddetached in a direction substantially tangential to the rotating direction of the developing device unit main body when a grip section is gripped and operated by the operator in the case where the developing agent cartridges are at a location substantially opposite an image carrier with respect to the rotary shaft. The channel base also has a recess formed opposite to the reaction well and recessed upward from the upper surface of the liquid introduction channel.