A method for protecting a mesh network, the method comprising: upon detection of a failure on a protected span, transmitting, by an end node located downstream of a signal stream on the protected span, an Automatic Protection Switch, APS request signalling along at least one protection path of the protected span according to configuration information of the end node; and upon reception of the APS request signalling, transmitting, by an end node located upstream of the signal stream on the protected span, an APS response signalling along a protection path, and performing a bridging/switching operation according to its configuration information; performing, by intermediate nodes receiving the APS response signalling, a straight-forward operation according to respective configuration information; and performing, by an end node receiving the APS response signalling and located downstream of the signal stream, a bridging/switching operation according to its configuration information; wherein before the detection of the failure, further comprising: configuring a node configuration information table for respective nodes in the mesh network, wherein the node configuration information table comprises a ID of a node, a corresponding High Ordered Optical Data Unit k, HO ODUk port, a corresponding HO ODUk state and a remote signalling; configuring span protection for the mesh network, configuring at least one protection path for each protected span, and configuring a Shared Mesh Protection, SMP configuration information table for nodes in the mesh network, wherein the SMP configuration information table comprises a Protection ID, PID, an operating port and a PID route; and the configuration information comprises the node configuration information table and the SMP configuration information table. upon detection of a failure on a protected span, transmitting, by an end node located downstream of a signal stream on the protected span, an Automatic Protection Switch, APS request signalling along at least one protection path of the protected span according to configuration information of the end node; and upon reception of the APS request signalling, transmitting, by an end node located upstream of the signal stream on the protected span, an APS response signalling along a protection path, and performing a bridging/switching operation according to its configuration information; performing, by intermediate nodes receiving the APS response signalling, a straight-forward operation according to respective configuration information; and performing, by an end node receiving the APS response signalling and located downstream of the signal stream, a bridging/switching operation according to its configuration information; configuring a node configuration information table for respective nodes in the mesh network, wherein the node configuration information table comprises a ID of a node, a corresponding High Ordered Optical Data Unit k, HO ODUk port, a corresponding HO ODUk state and a remote signalling; configuring span protection for the mesh network, configuring at least one protection path for each protected span, and configuring a Shared Mesh Protection, SMP configuration information table for nodes in the mesh network, wherein the SMP configuration information table comprises a Protection ID, PID, an operating port and a PID route; and the configuration information comprises the node configuration information table and the SMP configuration information table.