To provide a system capable of increasing failure resistance while suppressing bus usage efficiency degradation.

A CAN system 900 includes: a first node 91; and a second node 92. The first node transmits a re-transmission request frame for requesting frame re-transmission, if own node is in an error passive state when frame reception through a CAN bus 90 fails. The second node stores a frame transmitted to CAN bus in a storage part, obtains a frame whose re-transmission is requested by a re-transmission frame transmitted by the first node, and re-transmits the frame to the first node.