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Call content is sent from the SBC to the IS in an RTP media stream for each direction of an intercepted call. Call content will always be sent to the IP addresses and UDP ports specified by the intercept server in the Signaling Start Response message. The IS decides if it is sent to the LEA based on the configured warrant. The intercept server performs in-band tone detection and sends the appropriate call data messages to the LEA for this detection. The IS detects RFC2833 DTMF Relay RTP packets and sends the appropriate call data messages to the LEA. SBC detects out of band tones and sends the appropriate call data messages to the IS. The IS performs any gateway function of the audio signal required by the LEA before sending the call content to the LEA.
In some call scenarios, Sonus network elements are not part of the media path. This is referred to as "direct media." When LI and "direct media" are configured on the SBC, Lawful intercept takes precedence, and any direct media calls are converted to ordinary pass-through calls.
Intercept criteria are identified by an "Intercept_Criteria_Type" and "Intercept_Criteria" (or criteria ID) attribute. The SBC currently supports the following intercept criteria types:
Associated with each intercept type are corresponding criteria IDs.
To configure LI, see following pages:
A separate license is required on EMS and/or SBC to enable this service. Without these licenses, the APIs for this feature are not accessible. Only authorized users can access LI functions.
The following Centralized PSX diagram includes the SBC 5000 series for the example.
For EMS-related LI configurations, please see Sonus Insight User Guide and Insight Lawful Intercept Guide located at the Sonus Documentation and Support Portal.
The SBC ERE solution includes the following requirements:
Only "calea" users can access LI functions.
For EMA-related LI configurations, please see EMA User Guide.
When upgrading, and you wish to maintain the pre-existing centralized PSX LI solution, no change to local SBC user account is needed. But if a change to an existing solution is desired, or if you are switching to the new SBC ERE solution, a local SBC LI user account must be established.