SpaceWire physical level redundancy mechanism

SpaceWire is becoming a popular solution for spacecraft high-speed (10-200 Mbps) onboard communications as its simple standard provides great flexibility for solving a wide range of system requirements. However, the SpaceWire standard currently does not provide a redundancy mechanism. There are many ways to do this, but none are currently part of the SpaceWire standard. It could be with two separate protocol devices between systems, but the difficulty in implementation is just moved to the next higher level in the protocol stack. In this situation, the user of SpaceWire would need to determine when a protocol device has failed and than command a switchover to the alternate device. Another method would be to provide a mechanism for switchover to an alternate cable within the same protocol device that is transparent to the user. This method is described in this paper.