In one embodiment, a source routing device (e.g., root device) pre-computes diverse source-routed paths to one or more nodes in a computer network. Upon receiving a particular packet, the device forwards the particular packet on a source-routed first path of the pre-computed diverse paths. In the event the device implicitly detects failure of the first path, then it forwards a copy of the particular packet on a source-routed second path of the pre-computed diverse paths in response. In one embodiment, implicit failure detection comprises seeing a second (repeated) packet with the same identification within a certain time since the first packet, and the second packet is forwarded on the second path. In another embodiment, implicit failure detection comprises not seeing a link-layer acknowledgment returned or receiving an error notification from a node along the broken path, and a stored copy of the particular packet is forwarded on the second path.