A switch device for one-way transmission based on virtual local area network identifier; the switch device comprising: a switch, comprising: a first port; a second port; a third port configured to be coupled to the first port via a first path and coupled to the second port via a second path; and a controller coupled to the first port, the second port, and the third port; and the switch device further comprising a first programmable logic device coupled to the third port, wherein the first port is configured to receive a first data packet from a first external device; the controller is configured to pack the first data packet with a first virtual local area network identifier corresponding to the first path to generate a second data packet; the first programmable logic device is configured to store a mapping table, to receive the second data packet from the third port and to filter the second data packet according to a first filtering rule; the first programmable logic device is configured to overwrite, in response to the second data packet being matched with the first filtering rule, the first virtual local area network identifier by a second virtual local area network identifier corresponding to the second path to generate a third data packet; and the first programmable logic device is configured to transmit the third data packet to the second port via the second path so as to output the third data packet via the second port; wherein the first port is configured to receive an address query packet from the first external device and to transmit the address query packet to the third port, wherein the address query packet comprises an Internet protocol, IP, address; the first programmable logic device is configured to receive the address query packet from the third port and to broadcast the IP address to a second external device via the second port; the first programmable logic device is configured to receive a media access control, MAC, address from the second external device via the second port in response to broadcasting the IP address and to add a mapping relationship between the IP address and the MAC address to the mapping table in response to receiving the MAC address from the second external device; and the first programmable logic device is configured to generate a response packet corresponding to the address query packet by setting a source address of the response packet to the MAC address. a switch, comprising: a first port; a second port; a third port configured to be coupled to the first port via a first path and coupled to the second port via a second path; and a controller coupled to the first port, the second port, and the third port; and the switch device further comprising a first port; a second port; a third port configured to be coupled to the first port via a first path and coupled to the second port via a second path; and a controller coupled to the first port, the second port, and the third port; and the switch device further comprising a first programmable logic device coupled to the third port, wherein the first port is configured to receive a first data packet from a first external device; the controller is configured to pack the first data packet with a first virtual local area network identifier corresponding to the first path to generate a second data packet; the first programmable logic device is configured to store a mapping table, to receive the second data packet from the third port and to filter the second data packet according to a first filtering rule; the first programmable logic device is configured to overwrite, in response to the second data packet being matched with the first filtering rule, the first virtual local area network identifier by a second virtual local area network identifier corresponding to the second path to generate a third data packet; and the first programmable logic device is configured to transmit the third data packet to the second port via the second path so as to output the third data packet via the second port; wherein the first port is configured to receive an address query packet from the first external device and to transmit the address query packet to the third port, wherein the address query packet comprises an Internet protocol, IP, address; the first programmable logic device is configured to receive the address query packet from the third port and to broadcast the IP address to a second external device via the second port; the first programmable logic device is configured to receive a media access control, MAC, address from the second external device via the second port in response to broadcasting the IP address and to add a mapping relationship between the IP address and the MAC address to the mapping table in response to receiving the MAC address from the second external device; and the first programmable logic device is configured to generate a response packet corresponding to the address query packet by setting a source address of the response packet to the MAC address.