MOBILITY MANAGEMENT FOR MOBILE HOSTS

摘要

A system having a mobile host (1) which can attach to different access networks. The mobile host (1) has an identifier (NAI) which is independent of the access network (3A, 3B) to which the mobile host (1) is attached. The system has a database (UNS - User Name Service) which registers the association of the mobile host identifier (NAI) and the current communications address (IP address) of the mobile host (1). The mobile host (1) comprises a control unit (1A) which maintains a record of the correspondent host (2) with which the mobile host (1) is engaged in an active communications session; detects when the communications address (IP address) of the mobile host (1) changes, sends a message (HANDOVER MESSAGE) to the recorded correspondent host (2), the message containing the mobile host's (1) identifier (NAI). The correspondent host (2) then uses the identifier (NAI) to access the database (UNS) to obtain the changed communications address (IP address) of the mobile host (1).