When the Application Function (AF) requests the PCRF to report the
access network information, the PCRF provides the requested access network
information indication (for example, user location and/or user timezone
information) to the PCEF within the Required-Access-Info AVP which is included
in the Charging-Rule-Definition AVP of an appropriate PCC rule.
The PCRF also provides the ACCESS_NETWORK_INFO_REPORT event trigger
within the Event-Trigger AVP. If the ACCESS_NETWORK_INFO_REPORT event trigger
is set, upon installation, modification and removal of any PCC rule(s)
containing the Required-Access-Info AVP, the P-GW determines if it can obtain
the required location information for the used IP CAN type.
During bearer deactivation or UE detach procedure, the P-GW provides
the access network information to the PCRF within the TWAN-Identifier AVP. The
P-GW also provides information on when the UE was last known to be in that
location within the User-Location-Info-Time AVP, and/or UE-Local-IP-Address AVP
as applicable for S2a/S2b interface:
For Trusted WLAN, the User Location Information (ULI) is provided
in the TWAN Identifier AVP.
For Untrusted WLAN, the ULI contains the TWAN Identifier, the UE’s
Local IP address and optionally, UDP source port number (if NAT is detected).
When the ULI is requested by the PCRF and it’s not provided to the
PCEF, the PCEF provides the serving PLMN identifier within the
3GPP-SGSN-MCC-MNC AVP. And when the time zone is requested by the PCRF, the
PCEF provides it within the 3GPP-MS-TimeZone AVP. Please note that the timezone
is applicable only for Trusted WLAN interface. For WLAN access, the PCEF also
includes the AN-Trusted AVP while reporting access network information.
During the IP-CAN session termination procedure, the PCEF will, if
ACCESS_NETWORK_INFO_REPORT event trigger is set, provide the access network
information to the PCRF by including the ULI (if it was provided to the PCEF),
the information on when the UE was last known to be in that location within
User-Location-Info-Time AVP (if it was provided to the PCEF), the PLMN
identifier within the 3GPP-SGSN-MCC-MNC AVP (if the user location information
was not provided to the PCEF) and the timezone information within the
The WLAN location information received from S2a/S2b interface is
reported on all the P-GW supported interfaces (Gx, Gy, and Gz).