Method of performing a handover in a mobile communication system

摘要

The invention concerns a method, a terminal (40), a node (10) of a first access network (1), a node (20) of a second access network (2), a call server function (30), and a communication network (123) for performing a handover for a terminal (40) having a session-oriented first connection (100) with a communication partner (50) via the first access network (1). The terminal (40) detects the availability of the second access network (2), and registers via the second access network (2) at a call server function (30). The terminal (40) sends an invite message directed to the communication partner (50) via the second access network (2). The node (20) of the second access network (2) terminates the invite message, changes a Session Description Protocol payload of the invite message to an address of said node (20) of the second access network (2), and sends an invite message with the changed Session Description Protocol payload from said node (20) of the second access network (2) to the call server function (30). The invite message with the changed Session Description Protocol payload received by the call server function (30) is routed to a node (10) of the first access network (1), and a second connection (200, 2010) between the node (10) of the first access network (1) and the terminal (40) via the node (20) of the second access network (2) is opened.