A network system for allocating service nodes to a user terminal to login a network may comprises a gateway node, a plurality of service nodes, a sampling terminal, a gateway node, and a login node. The system may receive service nodes information of the plurality of service nodes from the sampling terminal; obtain from the sampling terminal network quality sampling data associating with each of the plurality of service nodes; identify the gateway node corresponding to the sampling terminal; select a plurality of candidate service nodes from the plurality of service nodes based on the network quality sampling data; obtain network quality parameters between each of the plurality of candidate service node and the gateway node; select a target service node from the plurality of candidate service nodes based on the network quality sampling data and the candidate node network quality parameters; and allocate the target service node to the gateway node.