Routing system, control element, routing method and forming method for exchanging table and forwarding table

In a routing method, a control element firstly forms a forwarding table and an exchanging table according to a routing table. Next, a first forwarding element receives a packet, and then obtains a label from the forwarding table according to a destination address of the packet, and determines to output the packet from the first forwarding element or a second forwarding element according to the label. If the packet is to be outputted from the first forwarding element, it is directly outputted to the destination address of the packet; otherwise the second forwarding element receives the packet and the label. Next, the second forwarding element obtains a next forwarding path from the exchanging table according to the label to forward the packet. The control element and the first and second forwarding elements constitute a routing system.