SBC acting as P-CSCF or I-BCF can be configured to intercept IMS sessions. This feature can also be used in non-IMS deployments, to intercept audio/video/clearmode and fax streams.
The figure below depicts the deployment scenario of the SBC to support Lawful Interception (LI).
SBC for Lawful Interception
- X1 interface: This interface is known as Provisioning interface that is supported by Sonus EMS using SOAP XML/TCP.
- X2 interface: This interface is known as Signaling interface that is supported by Sonus SBC to send call data (signaling) messages over TCP using an optional IPSec tunnel. This interface encapsulates a copy of the SIP signaling message sent/received towards/from the target.
- X3 interface: This interface is known as Media interface that is supported by Sonus SBC to send call content (media) messages over UDP only. These media streams (audio/video/image/clearmode) carries a copy of the stream sent/received towards/from the target.
At a high level, the functions performed by the Lawful Intercept are:
- Support of Encapsulation mode (multimedia) for all signaling messages and media streams; Encapsulation mode signifies intercepting the received or sent signaling or media stream, by appending an header with extra information, towards the Mediation Server.
- Support for SIP URI and DN based interception
- Support for intercepting RTP media types such as audio, video, image (fax), clearmode
- Support for intercepting any SIP signaling messages
Support for sending intercepted signaling messages over TCP, using an optional IPSec tunnel
EMS/PSX support for LI
For more information on EMS and PSX configuration for Lawful intercept, see Sonus Lawful Intercept.
For configuration details, see Configuring SBC For Lawful Interception
Overview
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