CALCULATING INITIAL FILTER CRITERION Russian patent published in 2011 - IPC H04L29/06 H04W4/02 H04W80/10 

FIELD: information technology.

SUBSTANCE: session initiation protocol containing a recipient uniform resource identifier is received. As a result of applying the initial filter criterion to the message, a message is sent to the application server and calculation of additional initial filter criteria is stopped. A return message is received from the application server, after which it is determined whether the uniform resource identifier has been changed by the application server. If the uniform resource identifier was changed by the application server, it is then determined whether or not to resume calculation of the initial filter criterion, and if the uniform resource identifier was not changed by the application server, calculation of the initial filter criterion is resumed.

EFFECT: enabling continuation of calculation of an initial filter criterion (IFC) during IFC calculation in the final call session control function, even when the recipient uniform resource identifier has been changed.

8 cl, 8 dwg