Vehicle network system and control method of vehicle network system

A control method of a vehicle network system including a plurality of control devices communicable with each other,

• wherein the plurality of control devices each provided by at least a memory and a memory includes:
• a control device that retains cluster information indicative of a cluster to which the control device belongs among a plurality of clusters being divisions, and that becomes an active state in response to an activation message from another control device including active-cluster information indicative of the cluster to be active that matches the cluster indicated by the cluster information;
• and
• a manager control device that has a function of changing the cluster information of the control device,
• the control method comprising:
• the control device determining whether or not the cluster information changed by the manager control device is appropriate;
• and
• the control device changing an activation condition of the control device upon determining that the cluster information changed by the manager control device is not appropriate.