Network system, control method, and control device

A network system having a plurality of networks, each network comprising a master processing unit and one or a plurality of slave processing units, the network system comprising:

• a first device having the master processing unit;
• a second device having the master processing unit and the slave processing unit;
• and
• a third device having the slave processing unit,
• wherein each of the first device, the second device, and the third device is configured to hold characteristic information indicating whether or not the device has the master processing unit or the slave processing unit,
• each master processing unit respectively comprises a device search unit configured to acquire the characteristic information from each of the first device, the second device, and the third device connected to a network managed by the respective master processing unit and to generate single-layer network configuration information indicating information of a device connected to each network managed by the respective master processing unit, and
• the first device comprises a network management unit configured to acquire single-layer network configuration information from each master processing unit comprised in the network system to generate multilayer network configuration information indicating a connection relationship of each device in the network system.