5 Network Element, and Reference point

23.1393GPP3GPP system - fixed broadband access network interworkingRelease 17Stage 2TS

5.1 Network Elements

5.1.1 3GPP network elements

The 3GPP network elements are defined in details in TS 23.401 [2], TS 23 402 [3] and TS 23.203 [4].

5.1.1.1 ePDG

The details of functionality of ePDG are described TS 23 402 [3].

The following enhancements are applicable: To support initiation of a Gateway Control Session over S9a from the PCRF when using untrusted access procedures, the ePDG is enhanced to transport UE Local IP address, UDP port number(s) for the UE connected to WLAN to the PCRF via the Gxb* in untrusted S2c and S2b PMIP-based or via the S2b reference points in case of S2b GTP-based.

5.1.1.2 PCRF

The enhancement of PCRF for supporting interworking with BBF Policy Framework is described in TS 23.203 [4] Annex P.

5.1.1.3 3GPP AAA Server

The 3GPP AAA Server is within the 3GPP network. The 3GPP AAA Server is defined in TS 23 402 [3] and TS 29.273 [25].

In order to support offline and online charging for Non-seamless-WLAN offloaded traffic in Broadband Fixed Access network, the 3GPP AAA Server is enhanced to exchange accounting messages from 3GPP AAA proxy in roaming scenario or from BBF AAA proxy in non-roaming scenario. The 3GPP AAA Server reports per-user charging/accounting information about NS-WLAN offloaded traffic to the HPLMN Charging System.

5.1.1.4 3GPP AAA Proxy

The 3GPP AAA Proxy is within the 3GPP network. The 3GPP AAA Proxy is defined in TS 23 402 [3] and TS 29.273 [25].

In order to support offline and online charging for Non-Seamless WLAN offloaded traffic in Broadband Fixed Access network, the 3GPP AAA Proxy in VPLMN is enhanced to relay accounting data received from the BBF AAA Proxy in fixed domain to the 3GPP AAA Server in HPLMN. The 3GPP AAA Proxy is further enhanced to report per-user charging/accounting information to the VPLMN Charging System for inter-operator settlement for roaming users.

5.1.2 BBF network elements

The BBF network elements BRAS, BNG, RG, BBF AAA proxy, BPCF are defined in details in BBF TR-058 [7], BBF TR-101 [8], BBF TR-145 [10] and BBF TR-134 [11].The BBF device represents any devices defined by Broadband Forum or supported by Fixed Broadband Access, as a PC, Media centre, etc., and they are considered outside the scope of 3GPP.

The definition of enhancements for BBF AAA for 3GPP interworking and for BPCF to support Policy & QoS interworking with mobile networks is specified in BBF TR-134 [11] and BBF TR-203 [6]

5.2 Reference Points

The reference points S1-MME, S1-U, S3, S4, S5, S6a, S8, S10, S11 are defined in TS 23.401 [2]. The reference points S2c, S6b, SWx, SWd, SWm, SWn, SWu, SGi, Gxc are defined in TS 23 402 [3]. The reference point Rx and Sd are defined in TS 23.203 [4].

Gx For purpose of BBF interworking it transfers the UE/H(e)NB Local IP address and the UDP port number if NAT/NAPT is detected in the BBF access network at which the H(e)NB is connected to.

Gxb* It connects the ePDG with the PCRF and transports UE Local IP address, UDP port number(s) for the UE connected to WLAN. It is used in untrusted S2c and S2b-PMIP case .This information triggers the PCRF to initiate the Gateway Control Session over S9a.

S2b For purpose of BBF interworking it transfers UE Local IP address and UDP port number(s) in cases of S2b-GTP. This information triggers the PCRF to initiate the Gateway Control Session establishment over S9a towards the BPCF.

S15 It supports the initiation, modification and termination of sessions between the HNB GW and PCRF to support CS sessions. This interface triggers the PCRF to request allocation of resources in the Fixed Broadband access network for CS sessions.

S9 For BBF interworking for WLAN UE roaming with home routed access and S2b/Gx being used to trigger the PCRF to initiate the Gateway Control Session establishment over S9a, or for BBF interworking using GTP Home Routed Traffic for H(e)NB, the S9 interface is enhanced to carry from the H-PCRF to the V-PCRF the UE/H(e)NB Local IP address and the UDP port number if NAT/NAPT is detected in the Fixed Broadband access network at which the H(e)NB is connected to.

S9a For purpose of BBF interworking it provides transfer of dynamic QoS control policies (QoS) from the Home PCRF to the BBF Policy Control function (BPCF) and in roaming scenario from the Visited PCRF and to the BBF Policy Control function (BPCF). Furthermore the S9a carry from the H-PCRF/V-PCRF the UE/H(e)NB local IP address, UDP port number(s) and/or FQDN of Fixed Broadband access network at which the H(e)NB is connected to. The S9a is based on enhancement of S9 reference point for supporting interworking with BBF Policy Framework.

SWa For purpose of BBF interworking it connects the BBF AAA proxy with the 3GPP AAA Server/Proxy and transports access authentication, authorization and accounting information in a secure manner. The transport of accounting information is applicable only to non-seamless WLAN offloaded traffic.

STa For purpose of BBF interworking it connects the BBF AAA proxy with the 3GPP AAA Server/Proxy and transports access authentication, authorization, mobility parameters and accounting information in a secure manner. The transport of accounting information is applicable only to non-seamless WLAN offloaded traffic.

The Reference points within the BBF access network are defined in BBF TR 058 [7], BBF TR-101 [8], BBF TR‑145 [10] and BBF TR-134 [11] and they are considered out of the scope of 3GPP.