A method and system are provided for integrating a WLAN radio access network into a GSM/GPRS core network wherein gateways are added that transparently transport services between the two networks. A further aspect of the invention is secure authentication. The system has two network elements: a Radio Link Manager (RLM) and a Radio Access Controller (RAC), and a software application, a Multi-Link Client (MLC) to control the functionality of the integration and the authentication. The MLC resides on a user device. The RAC provides protocol stacks and interworking functions to allow the MLC to talk to a Home Location Register (HLR). The RLM and MLC set up a "tunnel" employing, for example, PPP over Ethernet (PPPOE), and all of the data packets received on this tunnel are forwarded by the RLM to the Gateway GPRS Support Node (GGSN over a further tunnel using the GPRS Tunneling Protocol (GTP).