FIELD: information technology.
SUBSTANCE: disclosed is a session initiation protocol application server of an IP multimedia subsystem having processing means for handling a message received from a serving call/state control function, the means being configured to handle the message based on a header of the message containing the URI of the served user, this header having been introduced by the serving call/state control function and being other than the P-Asserted Identity and the R-URI.
EFFECT: improved calling procedure.
11 cl, 7 dwg
