Vehicle-mounted apparatus and a method for relaying

A vehicle-mounted apparatus, which is connected to a plurality of vehicle-mounted Electronic Control Units “ECUs”, for relaying messages output by the plurality of vehicle-mounted ECUs, the vehicle-mounted apparatus comprising:

• a first processing unit for performing relay processing on the messages, the first processing unit being connected to each of the plurality of vehicle-mounted ECUs;
• a second processing unit for performing relay processing on the messages, the second processing unit being connected to each of the plurality of vehicle-mounted ECUs;
• a first routing table including a relay destination of each message to be processed at the first processing unit;
• and
• a second routing table including a relay destination of each message to be processed at the second processing unit,
• wherein each of the first processing unit and the second processing unit includes a connection unit to which wiring connected to the plurality of vehicle-mounted ECUs is connected,
• the first processing unit performs the relay processing based on the first routing table, and
• the second processing unit performs the relay processing based on the second routing table;
• and
• wherein the first routing table includes the relay destination of each message to be processed at the second processing unit, and
• the first processing unit
• determines whether preparations for the relay processing at the second processing unit have been completed, and
• performs, when the preparations for the relay processing at the second processing unit have not been completed, the relay processing on the messages to be processed at the first processing unit and the messages to be processed at the second processing unit based on the first routing table.