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Modified: for 12.1.2

Overview


The SBC Core platforms support Lawful Intercept (LI) functionality using one of the following solutions:

  • Centralized PSX solution consisting of an external PSX, a third-party Intercept Server (IS), and RAMP
  • SBC ERE solution consisting of the ERE, a third-party Intercept Server and EMA

The SBC works in conjunction with the Intercept Server as well as the ERE and EMA (or an external PSX and RAMP) to provide call data and call content to law enforcement agencies for calls involving identified intercept subjects. When it receives matching LI criteria in a policy response from the ERE (or PSX), the SBC routes the call as directed and additionally reports call events to the Intercept Server. It also sends media stream (call content) to an IP address provided by the Intercept Server.

The SBC supports four types of LI:

  • Default LI
  • IMS LI
  • PCSI LI
  • PacketCable 2.0 LI

In order to intercept media packets, ensure RAMP is either the same or a higher version as that of the SBC and PSX platforms. 


The following table describes the Call Data Channel (CDC) configuration information required to distinguish between Default LI, IMS LI, and PCSI (P-Com.Session-Info) LI, and PacketCable 2.0 LI. It also lists the types of LI supported on different platforms:

LI Types and Supported Platforms

LI TypeCDC ConfigurationPlatformsRouting PolicyLI InterfaceStreams Supported
Intercept StandardVendor IdD-SBCSBC SWe/SBC 7000External PSXEREX1X2X3D-SBCSBC SWe/SBC 7000
Legacy LI (default)PacketCable, PacketCablePlusEtsiNone/Utimaco/Verint

Supported

SupportedSupportedSupportedSOAP
  • RADIUS
  • RADIUS over IPsec
UDPAudio OnlyAudio only
PCSI LIPacketCableSs8SupportedSupportedSupportedNot SupportedTLSNot Supported
  • TCP
  • TCP over IPsec

Audio,Video and T140

Audio, Video and T140
IMS LI3gpp/etsiVerint/utimaco/none/GroupTwoThousandSupportedSupportedSupportedSupportedSOAP
  • DSR
  • DSR over IPsec
  • TLS
  • UDP
  • UDP over IPsec
  • TCP
  • TCP over IPsec
  • TLS
Audio OnlyAll Streams
PacketCable 2.0PacketcableVTwonone/atos Not SupportedSupportedSupportedSupportedSOAP
  • Diameter
  • Diameter over IPsec
  • UDP
  • UDP over IPsec
Not SupportedAudio, Video

Call Data Channel (CDC) Model

The SBC supports various types of LI using a generic Call Data Channel (CDC) model. This facilitates adding support for new types of LI. The CDC configuration model is described as follows:

  • The CDC model includes two fields, vendorId and interceptStandard, to support identifying and configuring the various LI types.
  • Each Mediation Server is configurable to support both signaling and media interception. Separate configuration fields are present under the Mediation Server to handle this functionality.
  • The CDC model for a given mediation server allows media interception over UDP and/or TCP.
  • The CDC model for a given mediation server supports signaling interception either over TCP or UDP. It does not support both simultaneously.

IMEI and IMSI-based Interception

The SBC supports IMS Lawful Interception (LI) based on the International Mobile Equipment Identity (IMEI) and International Mobile Subscriber Identity (IMSI) numbers. Specifically, IMEI and IMSI targets are configurable in the X1 interface.

The SBC supports the following LI functionality:

  • The SBC receives IMEI in the Contact header of SIP REGISTER and INVITE messages and IMSI in the FROM/TO headers of SIP REGISTER messages.
  • The SBC intercepts the ingress leg if IMEI/IMSI is found as the target for both SIP registration and calls.
  • If IMEI/IMSI is not received in the SIP Invite for a registered call, then IMEI/IMSI is picked from registration and the SBC sets up the interception for that target. (This is applicable for Out-of-Dialog messages as well).
  • In the above mentioned registered calls case, the ingress leg is intercepted for mobile-originated calls and the egress leg is for mobile-terminated calls.