In-vehicle device, in-vehicle communication system, and communication control method

An in-vehicle device connected to a plurality of peripheral in-vehicle devices, each of the peripheral in-vehicle devices having a plurality of communication ports, the in-vehicle device being provided with: a storage unit that holds port information indicating the correspondence between the plurality of communication ports in each of the peripheral in-vehicle devices and devices connected to each of the communication ports; and a transmission unit that transmits the port information to the storage unit on the basis of the port information stored in the storage unit. Output target port information indicating a communication port that is to be an output target port of control information for controlling the device or device control information obtained on the basis of the control information, among the plurality of communication ports, is included in a frame together with the control information, and is transmitted to the peripheral in-vehicle device. 一种车载装置，连接于多个周边车载装置，各所述周边车载装置具备多个通信端口，所述车载装置具备：存储部，保持表示各所述周边