Network system and conversion apparatus crossing different transmission protocols

A network system crossing transmission protocols, comprising:

• a first conversion apparatus;
• a second conversion apparatus;
• a user device wherein a user packet is transmitted between the user device and the first conversion apparatus in accordance with transmission control protocol (TCP);
• and
• a server device wherein a server packet is transmitted between the server device and the second conversion apparatus in accordance with TCP, wherein
• data transmission between the first conversion apparatus and the second conversion apparatus is performed in accordance with multipath transmission control protocol (MPTCP), wherein the first conversion apparatus takes its network address and network port as a source address and a source port, and takes network address and network port of the second conversion apparatus as a destination address and a destination port, and wherein the second conversion apparatus takes its network address and network port as a source address and a source port, and takes network address and network port of the first conversion apparatus as a destination address and a destination port,
• the user packet is transmitted between the first conversion apparatus and the user device in accordance with network addresses of the user device and the server device, and
• the server packet is transmitted between the second conversion apparatus and the server device in accordance with the network addresses of the user device and the server device;
• wherein the first conversion apparatus comprises a user-path database for storing connection information, and multipath transmission control protocol (MPTCP) packets are transmitted between the first conversion apparatus and the second conversion apparatus in accordance with the connection information stored in the user-path database;
• and
• the second conversion apparatus comprises a server-path database for storing the connection information, and the multipath transmission control protocol (MPTCP) packets are transmitted between the second conversion apparatus and the first conversion apparatus in accordance with the connection information stored in the server-path database;
• wherein after the first conversion apparatus receives the user packet from the user device, the first conversion apparatus transmits a coordination path packet to the second conversion apparatus in accordance with TCP wherein the coordination path packet includes a header and a content, a source address of the coordination path packet is set to the network address of the first conversion apparatus, and the network address of the user device is included in the content of the coordination path packet;
• wherein the second conversion apparatus designates routing paths connected between the second conversion apparatus and the first conversion apparatus and using MPTCP for the data transmission according to the coordination path packet, stores the connection information corresponding to the routing paths in the server-path database, and transmits the connection information corresponding to the routing paths to the first conversion apparatus;
• and the first conversion apparatus stores the connection information corresponding to the routing paths in the user-path database.