A method for a power-saving operation of a subscriber line (100.1) terminated by an access interface (23.1) implemented in a customer router and by a port (51.1) implemented in an access network device , the customer router further comprising a wireless network interface configured to communicate via a wide-area wireless network with a network device using a wireless network protocol, wherein the method comprises the steps of: a) deactivating the port (51.1) of the access network device in response to a time scheduler and/or in response to a predefined event, which is detected by the access network device ; b) activating the port (51.1) deactivated in step a) by b1) transmitting, by the customer router , a request message for activating the deactivated port (51.1) of the access network device via its wireless network interface to the network device ; b2) generating, at the network device , a port activating signal in response to the request message of step b1); b3) transmitting, by the network device , the port activating signal generated at step b2) to the access network device , and b4) activating, by the access network device , the port deactivated at step a) so that the subscriber line (100.1) will become available for data transmission between the customer router and the access network device , wherein the wide-area wireless network is a low-power wide-area radio network, LPWAN, and the wireless network interface of the customer router is a low-power radio network interface configured to communicate via the low-power wide-area radio network LPWAN using a low-power wide-area network protocol. a) deactivating the port (51.1) of the access network device in response to a time scheduler and/or in response to a predefined event, which is detected by the access network device ; b) activating the port (51.1) deactivated in step a) by b1) transmitting, by the customer router , a request message for activating the deactivated port (51.1) of the access network device via its wireless network interface to the network device ; b2) generating, at the network device , a port activating signal in response to the request message of step b1); b3) transmitting, by the network device , the port activating signal generated at step b2) to the access network device , and b4) activating, by the access network device , the port deactivated at step a) so that the subscriber line (100.1) will become available for data transmission between the customer router and the access network device , wherein the wide-area wireless network is a low-power wide-area radio network, LPWAN, and the wireless network interface of the customer router is a low-power radio network interface configured to communicate via the low-power wide-area radio network LPWAN using a low-power wide-area network protocol. b1) transmitting, by the customer router , a request message for activating the deactivated port (51.1) of the access network device via its wireless network interface to the network device ; b2) generating, at the network device , a port activating signal in response to the request message of step b1); b3) transmitting, by the network device , the port activating signal generated at step b2) to the access network device , and b4) activating, by the access network device , the port deactivated at step a) so that the subscriber line (100.1) will become available for data transmission between the customer router and the access network device , wherein the wide-area wireless network is a low-power wide-area radio network, LPWAN, and the wireless network interface of the customer router is a low-power radio network interface configured to communicate via the low-power wide-area radio network LPWAN using a low-power wide-area network protocol. <EOS>