The Routing and Control Board (RCB) is responsible for system management in a QFX10008 or QFX10016. The switch chassis can run with one or two RCBs. Base configurations ship with one RCB that can be expanded with a second RCB for a fully-redundant system. When two RCBs are installed, one functions as the master and the second as a backup. If the master RCB is removed, the backup restarts and becomes the master.