In one embodiment, a node comprises a first network interface and a second network interface. The node further comprises a first bus guardian that asserts a first bus guardian signal when the second network interface is allowed to transmit and a second bus guardian that asserts a second bus guardian signal when the first network interface is allowed to transmit. The first network interface is not allowed to transmit unless the second bus guardian asserts the second bus guardian signal. The second network interface is not allowed to transmit unless the first bus guardian asserts the first bus guardian signal.