Solutions for Next Generation Networks
In IMS-based ôNext Generation Networksö there are various possibilities to intercept IP multimedia services. A best-practice LI solution for a NGN operator depends very much on regulatory requirements and on the technical capabilities of network components. The diagram below shows a surveillance solution for SIP-based multimedia services in an IMS network. In case other non-SIP services are provided as well, further interception methods may be required.
The surveillance of SIP services is primarily done by the CSCF component (Call Session Control Function) in the IMS core network. Signaling messages to or from a target ID (e.g. SIP-URI or Tel-URL) can be dublicated and forwarded to the LIMS system. To enable the legal interception of call content data, the LIMS system must activate the intercept on the appropriate gateway or router (e.g. media gateway, session border controller) in real-time without any delay after the receipt of the call-setup signal. The delivery of the intercepted data is done over standardized handover interfaces compliant to ETSI or ANSI/ATIS standards as required by national laws and regulations.