Method for lawful interception during call forwarding in a packet-oriented telecommunications network

摘要

The invention relates to a method for lawful interception in the case of call forwarding (AW_TlnB) in a packet-oriented telecommunications network (TK1, TK2, TK3), in which switching functions (S-CSCF1, . . . , P-CSCF3) are made available by servers. The additional aim in this telecommunications network (TK1) is to monitor connections of a subscriber (Tln B) with call forwarding (AW_TlnB) by means of lawful interception. In this case, monitoring (ÜW_TlnB) of the connections of the subscriber (Tln B) is notified to a first switching function (S-CSCF1) which is responsible for a called subscriber (Tln B) with call forwarding (AW_TlnB). The first switching function (S-CSCF1) then writes (23) a tag for said subscriber (Tln B) to a predetermined parameter of a switching protocol. Only then is signalling of call forwarding (AW-TlnB) carried out to a second switching function (S-CSCF2) which is responsible for a calling subscriber (Tln A) and the connection is then forwarded to a third switching function (S-CSCF3). In this case, this third switching function (S-CSCF3) then identifies and initiates the monitoring (ÜW_TlnB) of the called subscriber (Tln B) on the basis of the predetermined parameter of the switching protocol. The major advantage of the method according to the invention is that it is still possible for a department or authority who is empowered to carry out monitoring to monitor (ÜW_TlnB) the contents of connections in a packet-oriented telecommunications network (TK1) even in the case of call forwarding (AW_TlnB).