4.2.4 Architecture for non-seamless WLAN offload by the Fixed Broadband Access network

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

Figure 4.2.4-1, 4.2.4-2, 4.2.4-3, 4.2.4-4, 4.2.4-5, and 4.2.4-6 show the reference architectures for NSWO. The non-seamless traffic is routed to an external network directly from BBF network.

Although this clause describes only NSWO architecture scenarios, both NSWO and EPC-routed can co-exist during the network operation.

Architecture scenario A: AF in 3GPP operator’s network

Figure 4.2.4-1: NSWO for 3GPP domain supporting the AF – non-roaming scenario

Figure 4.2.4-2: NSWO for 3GPP domain supporting the AF – roaming scenario

In this architecture scenario the AF is located in the 3GPP domain.

Architecture scenario B: AF ("BBF AF") in BBF domain

Figure 4.2.4-3: NSWO for 3GPP over BBF domain supporting the AF – non-roaming scenario

Figure 4.2.4-4: NSWO for 3GPP over BBF domain supporting the AF – roaming scenario

In this architecture scenario the AF ("BBF AF") is located in the BBF domain.

NOTE: The "BBF AF" and E/G reference point are out of 3GPP scope.

In this architecture scenario Rx signalling is supported over the S9a reference point.

The following assumptions are made about functionality in the BBF Access Network:

– The BPCF needs to map the request received over E/G (with UE local IP address) to the right IP-CAN session over S9a (i.e. session binding in BPCF) in order to find the right PCRF.

– The BPCF maps the signalling received from the BBF AF via G/E reference point in BBF domain to Rx signalling over S9a reference point.

Architecture scenario C: TDF

Figure 4.2.4-5: NSWO with TDF – non-roaming scenario

Figure 4.2.4-6: NSWO with TDF – roaming scenario

In this architecture alternative:

– Multiple TDFs may be deployed

– Sd is an intra-operator interface. This architecture variant is therefore limited to the case where the BBF domain and 3GPP domain are owned by the same operator.

– For roaming scenarios the TDF belongs to and is controlled by the VPLMN.

– For the solicited application reporting mode, the PCRF shall initiate the Sd interface triggered by S9a establishment, taking into account subscription data (verified by using e.g. IMSI, received from the BPCF).

– Home routed traffic (tunnelled using SWu, S2c) will not be subjected for packet inspection by the TDF.

– Policies for roaming users may be locally configured in the V-PCRF and/or TDF.

The following assumptions are made regarding functionality in the BBF Access Network:

– The BBF network routes the offloaded traffic subject to packet inspection and the offloaded traffic not subject to packet inspection via the same TDF, or

– The BBF network may be configured in such a way that the traffic determined to be subject to packet inspection is routed via the TDF. Traffic that is not subject to for packet inspection may physically bypass the TDF.

Editor’s note: The support of differentiating routing handling for the traffic is subjected for packet inspection and the traffic not subjected for packet inspection by BBF access network requires further study in Broadband Forum.