Network system and routing method

A routing method, being applied to a network system, wherein the network system comprises a plurality of nodes and a controller, each of the plurality of nodes comprises at least one connection port;

• every two adjacent nodes are connected through the at least one connection port of the plurality of nodes to form a plurality of links, and the routing method comprises:
• transmitting identification information of the plurality of nodes and support rates of the at least one connection port of the plurality of nodes to the controller through the plurality of nodes;
• receiving the identification information to construct a network topology diagram and receiving the support rate of the at least one connection port of the plurality of nodes through the controller;
• monitoring data rates of the at least one connection port of the plurality of nodes through the controller;
• receiving a route planning request through the controller;
• respectively calculating costs of the plurality of links according to the data rates of the at least one connection port of the plurality of nodes and the support rates of the at least one connection port of the plurality of nodes after receiving the route planning request through the controller;
• searching a plurality of candidate paths between a source-destination pair according to the route planning request and the network topology diagram through the controller;
• summing the costs of the plurality of links passed by each candidate path to acquire a sum of link-cost of each candidate path through the controller;
• and
• selecting one of the candidate paths with the smallest sum of link-cost as a packet transmitting path between the source-destination pair.