A network topology generation method, wherein the method comprises: receiving , by a network device working at a physical layer, a first packet from central equipment, wherein the first packet comprises port indication information and at least one data block, and the port indication information is used tc indicate a destination port of a further network device to which each of the at least one data block in the first packet is to be sent; and sending , by the network device, device information to the central equipment; wherein the method further comprises: in response to receive the first packet, determining by the network device, the control data block in the at least one data block based on the port indication information; wherein the sending device information to the central equipment comprises: generating , by the network device, a packet by using a control port, wherein the packet comprises port indication information and a second control data block, the port indication information is used to indicate a source port of the second control data block, and the second control data block carries the device information; wherein the source port of the control data block is a control port of the network device, and sending by the network device, the packet to the central equipment, wherein the device information is sent according to a device information sending instruction in the control data block of the first packet, wherein the device information is configured to be used by the central equipment to generate a network topology at the physical layer using a function of constructing a network topology for the network device at the physical layer. receiving , by a network device working at a physical layer, a first packet from central equipment, wherein the first packet comprises port indication information and at least one data block, and the port indication information is used tc indicate a destination port of a further network device to which each of the at least one data block in the first packet is to be sent; and sending , by the network device, device information to the central equipment; wherein the method further comprises: in response to receive the first packet, determining by the network device, the control data block in the at least one data block based on the port indication information; wherein the sending device information to the central equipment comprises: generating , by the network device, a packet by using a control port, wherein the packet comprises port indication information and a second control data block, the port indication information is used to indicate a source port of the second control data block, and the second control data block carries the device information; wherein the source port of the control data block is a control port of the network device, and sending by the network device, the packet to the central equipment, generating , by the network device, a packet by using a control port, wherein the packet comprises port indication information and a second control data block, the port indication information is used to indicate a source port of the second control data block, and the second control data block carries the device information; wherein the source port of the control data block is a control port of the network device, and sending by the network device, the packet to the central equipment, <EOS>