Redundancy is one of the key requirements placed on power systems, it is particularly important for critical protection and substation automation applications. Redundant systems eliminate single points of failure and improve overall system availability, security and dependability. As Ethernet communication is becoming more and more common in protection schemes in substations, the redundancy requirements no longer cover only protection devices but also the communication systems within the substation. Indeed, to achieve a high system reliability and availability, the communication network needs to avoid any traffic interruption when one of its elements is disturbed.