Communication system and communication method

摘要

GW apparatuses send messages including data being sent from ECUs to a distribution apparatus without sending to an ECU. The distribution apparatus stores the messages on a database, and sends the messages to an ECU, and an ECU. In a case, the distribution apparatus sends the messages in a message sending order and the GW apparatuses relays the messages being sent from the distribution apparatus to the ECUs. The message sending order may be an order in which the distribution apparatus receives the messages an ascending (descending) order of values corresponding to message IDs applied to the messages or an ascending order of message received time of the messages.