Method and system of data routing

The invention discloses a method and a system for data routing. When a piece of user equipment (UE) is accessed into a mobile core network through a dependable fixed network, the method comprises: sending a tunnel establishment request to a mobile access gateway through a routing gateway (RG) and carrying the downlink information of tunnel negotiation after the UE is accessed into the RG; replying a response of tunnel establishment and carrying the uplink information of tunnel negotiation after the tunnel establishment request is received by the mobile access gateway; finishing the tunnel establishment with the mobile access gateway through a dynamic negotiation after the response of the tunnel establishment is received by the RG; and packaging and forwarding the data message of the UE via the tunnel established between the RG and the mobile access gateway, when a business is accessed through the mobile core network by the UE. According to the method and the system of the invention, the establishment of the tunnel and the adoption of packaging the data message by the tunnel help to prevent the data message from being discarded by a broadband network gateway/ broadband remote access server (BNG/BRAS).