Some embodiments provide a method for a particular FE in a network of FEs. The method receives a data message at a first port of the FE. The data message includes a header that specifies an egress port for each FE along a path from a source of the data message to a destination of the data message and an ingress port for at least each FE along the path that the data message has previously traversed. The method determines that the particular egress port specified for the FE is a second port that is not operational. The method generates a path failure message specifying that the second port is not operational and including a header that uses the egress ports and ingress ports in the data message. The method sends the path failure message out of the first port for delivery to the source of the data message.