E.7 Untrusted non-3GPP Access Network Information

29.2143GPPPolicy and charging control over Rx reference pointRelease 17TS

The PCF provides the AF with the access network information as described in clause 4.4.1, with the following differences:

– The RAT-Type AVP shall be set to "WLAN" and AN-Trusted AVP shall be set to "Untrusted" when over the N7 reference point the received "ratType" attribute is "WLAN".

– The ePDG address used as IPSec tunnel endpoint with the UE, received over the N7 reference point within the "anGwAddr" attribute included in the "servNfId" attribute, is encoded in the AN-GW-Address AVP.

– The serving network identifier received over the N7 reference point within the "servingNetwork" attribute is encoded in the 3GPP-SGSN-MCC-MNC AVP.

If the NetLoc-Untrusted-WLAN feature is supported, reporting access network information procedure described in clauses 4.4.4 and 4.4.6.7 shall apply with the exceptions specified in clause E.1 and with the exception of:

– The user location information is encoded as follows:

a) The UE local IP address (used to reach the N3IWF or ePDG) received over the N7 reference point in the "ueIpv4Addr" or "ueIpv6Addr" attribute of the "n3gaLocation" attribute, if available, is encoded in the UE-Local-IP-Address AVP.

b) The UDP source port or the TCP source port received over the N7 reference point in the "portNumber" attribute if available, is encoded within the UDP-Source-Port AVP or the TCP-Source-Port AVP as indicated by the "protocol" attribute, if available.

NOTE 1: When the UE reaches the ePDG via a NAT, the combination of UE local IP address and the UE source port is needed for lawful interception purposes. The UE source port may be either a UDP or a TCP port, and it is indicated in the "protocol" attribute received over the N7 reference point.

c) The WLAN location information received in the "twapId" attribute of the "n3gaLocation" attribute, if available, is encoded in the TWAN-Identifier AVP.

– The UE time zone information is included within 3GPP-MS-TimeZone AVP, if available.

NOTE 2: EPC does not support time zone reporting when the access network is untrusted WLAN.

When reporting IP-CAN_CHANGE specific action, the PCF shall, in addition to the IP-CAN-Type AVP and RAT-Type AVP, provide the AN-Trusted AVP set to "Untrusted". The PCF provides also the AF with the ePDG IP address used as IPSec tunnel endpoint with the UE, if received, encoded in the AN-GW-Address AVP.