A computer-implemented method is performed by a client machine to establish communication with a data server. The client machine sends a first communication request to a directory server having information concerning available data servers that provide specific data to the client machine. The client machine further determines whether a first socket is established to allow communication with the directory server within a first predetermined period of time. When the first socket is established, the client machine receives the information concerning the available data servers from the directory server and establishes a target socket with a data server selected from the available data servers for receiving the specific data. However, when the first socket is not established, the client machine sends more communication requests to secondary servers according to a predetermined order, until the client machine receives the information concerning the available data servers or the specific data.