17.2. PE Failures

Consider a host CE1 that is dual-homed to PE1 and PE2. If PE1 fails, a remote PE, PE3, can discover this based on the failure of the BGP session. This failure detection can be in the sub-second range if Bidirectional Forwarding Detection (BFD) is used to detect BGP session failures. PE3 can update its forwarding state to start sending all traffic for CE1 to only PE2.