A method of securely initialising subscriber and security data in a mobile routing system when the subscribers are also subscribers of a radio communication network. The method comprises, within the mobile routing system, authenticating subscribers to the mobile routing system using an authentication procedure defined for the radio communication network, collecting subscriber information from relevant nodes of the radio network, and agreeing upon keys by which further communications between the subscribers and the mobile routing system can take place, and using said subscriber information and keys in the provision of mobility services to subscriber mobile nodes and correspondent nodes.