In the EPC network, the ePDG is the gateway which allows interworking between non-3GPP access and 3GPP network. The ePDG functionalities are specified in TS 23.402
The ePDG shall include an IRI-POI that has the LI capabilities to generate the target UE's bearer related xIRI.
In addition, the ePDG shall include a CC-POI that has the LI capabilities to duplicate the user plane packets from the EPS bearers related to a target UE.
shows the LI architecture for ePDG based interception.
The LICF present in the ADMF receives the warrant from an LEA, derives the intercept information from the warrant and provides the same to the LIPF.
The LIPF present in the ADMF provisions IRI-POI present in the ePDG, MDF2 and MDF3 over the LI_X1 interfaces. To enable the interception of the target's user plane packets (e.g. when the warrant requires the interception of communication contents), the CC-POI present in the ePDG is also provisioned with the intercept data.
The IRI-POI present in the ePDG detects the target UE's bearer activation, modification and deactivation, generates and delivers the xIRI to the MDF2 over LI_X2. The MDF2 delivers the IRI messages to the LEMF over LI_HI2.
The CC-POI present in the ePDG generates the xCC from the user plane packets and delivers the xCC (that includes the correlation number and the target identity) to the MDF3. The MDF3 delivers the CC to the LEMF over LI_HI3.
The target identities which the LIPF present in the ADMF provisions to the IRI-POI and CC-POI present in the ePDG are specified in TS 33.107
The IRI-POI present in the ePDG shall generate xIRI, when it detects the applicable events specified in TS 33.107
The list of xIRI parameters are specified in TS 33.128
. Each xIRI shall include at the minimum the following information:
Bearer related information.
The parameters in each xIRI are defined in TS 33.128
The ePDG shall provide the IRI-POI and CC-POI functions in the following network topology cases: