A network element, NE, configured to operate in a source routing network, wherein the NE comprises: a receiver; a transmitter; and a processor coupled to the receiver and the transmitter and configured to cause the NE to: receive from an upstream NE, a liveness protection probe comprising a header that comprises a list of one or more ordered connection identifiers that indicate a network path traversing the source routing network through which the liveness protection probe should be forwarded; replacing a connection identifier, in the list, that identifies the link over which the upstream NE transmitted the liveness protection probe with a second connection identifier that identifies a link that can be used to return to the upstream NE from the NE; transmit the liveness protection probe toward a downstream NE according to the connection identifiers; receive the liveness protection probe, having a header that comprises a list of ordered connection identifiers including the second connection identifier, from the downstream NE; and transmit the liveness protection probe to the upstream NE according to the second connection identifier contained within the header. a receiver; a transmitter; and a processor coupled to the receiver and the transmitter and configured to cause the NE to: receive from an upstream NE, a liveness protection probe comprising a header that comprises a list of one or more ordered connection identifiers that indicate a network path traversing the source routing network through which the liveness protection probe should be forwarded; replacing a connection identifier, in the list, that identifies the link over which the upstream NE transmitted the liveness protection probe with a second connection identifier that identifies a link that can be used to return to the upstream NE from the NE; transmit the liveness protection probe toward a downstream NE according to the connection identifiers; receive the liveness protection probe, having a header that comprises a list of ordered connection identifiers including the second connection identifier, from the downstream NE; and transmit the liveness protection probe to the upstream NE according to the second connection identifier contained within the header. receive from an upstream NE, a liveness protection probe comprising a header that comprises a list of one or more ordered connection identifiers that indicate a network path traversing the source routing network through which the liveness protection probe should be forwarded; replacing a connection identifier, in the list, that identifies the link over which the upstream NE transmitted the liveness protection probe with a second connection identifier that identifies a link that can be used to return to the upstream NE from the NE; transmit the liveness protection probe toward a downstream NE according to the connection identifiers; receive the liveness protection probe, having a header that comprises a list of ordered connection identifiers including the second connection identifier, from the downstream NE; and transmit the liveness protection probe to the upstream NE according to the second connection identifier contained within the header.