Abstract: In a radio telecommunication system, the performance of a mobile unit can be significantly improved during a hand-over procedure by reusing existing security associations that correspond to the mobile unit. By reusing existing security associations, a mobile unit can begin secure communications immediately following the hand-over. Otherwise, and in accordance with conventional practice, the mobile unit will have to undertake the time consuming task of renegotiating the required security associations, before it can begin transmitting and receiving secure communications.

Abstract: In a mobile, wireless telecommunications network, communications relating to a mobile terminal can be protected during a handover of the mobile terminal from a first access point to a second access point. This may be accomplished by transmitting a security token from the first access point to the mobile terminal, and then from the mobile terminal to the second access point, over the radio interface. Thereafter, the security token is transmitted from the first access point to the second access point through the fixed network to which both the first and the second access points are connected. The communications link between the mobile terminal and the second access point needed to achieve secure handover is then established only if the second access point determines that the security token received from the mobile terminal matches the security token received from the first access point.