As the interception of IRI and CC is required for all targeted VoIP calls, including forwarded and transferred calls, the CC shall be correlated with the IRI. The CC Interception Triggering Function triggers the CC interception for a call at the CC Intercept Function. The placement of the CC Interception Triggering Function is dependent on CSP network implementation, the call scenario, and the placement of network nodes that have access to the voice media.
The CC Interception Triggering Functions sends a CC intercept trigger to the CC Interception Function to activate CC interception for a call.
The intercept trigger, at the minimum, shall consist of the following:
The Correlation Identifier is used correlate the CC with the corresponding IRI data and is delivered from the CC Intercept Function in the intercepted media packet (i.e., CC) over the X3 interface to the Delivery Function 3.
The Media Identifier is used to identify the media packets that have to be intercepted. The technique used in defining the Media Identifier is implementation specific.
The information passed in this CC intercept trigger shall adhere to the security requirements outlined in clause 8
The mechanism used to provide the correlation between CC and IRI is implementation specific. For instance:
The CC Interception Triggering Function may send the correlation identifier value to the CC Interception Function that forwards it to DF3 onto X3 interface;
The CC Interception Triggering Function may send the correlation identifier (onto X2 interface) to the DF2 that forwards it to DF3. In this case the SDP information may be used to associate the CC packets with the IRI.