1. A method, comprising: pre-computing diverse source-routed paths to one or more nodes in a computer network by a source routing device; receiving a particular packet at the device; determining an identification of the particular packet; forwarding the particular packet on a source-routed first path of the pre-computed diverse paths; implicitly detecting failure of the first path by the device by detecting a second packet with a same identification as the particular packet that has been received at the source routing device after the particular packet has already been received at the device and prior to expiration of a timer, wherein the detecting of the same identification indicates that the second packet is a repeated packet and has already been forwarded from the source routing device along the first path and should not again be forwarded along the first path; and forwarding a copy of the particular packet on a source-routed second path of the pre-computed diverse paths in response to the implicitly detected failure of the first path.