Lawful Interception (LI) implementation guidance; LI for IMS based services
The present document provides architectural diagrams, conceptual scenarios, flow-diagrams, examples, and other background information which can be useful to implement the LI functions defined in TS 33.126 [2], TS 33.127 [3] and TS 33.128 [4].
The present document covers the LI for IMS based services that focus on illustrating the LI aspects of session-based IMS sessions which include the architecture topologies and the call flows covering basic sessions, redirected sessions, target non-local ID, conferencing, roaming (Local Breakout and Home-routed) scenarios. The IMS based STIR/SHAKEN related LI reporting are illustrated in TR 33.929-2 [10].
The LI for IMS-based services is agnostic to the packet core network.