For untrusted non-3GPP access, the N3IWF is the access network node that provides QoS signalling to support QoS differentiation and mapping of QoS flows to non-3GPP access resources.
For trusted non-3GPP access, the TNGF is the access network node that provides QoS signalling to support QoS differentiation and mapping of QoS flows to non-3GPP access resources.
For wireline access, the W-AGF serving the 5G-RG is the access network node that provides QoS signalling to support QoS differentiation and mapping of QoS flows to non-3GPP access resources.
A QoS flow is controlled by the SMF and can be preconfigured, or established via the UE requested PDU Session establishment via non-3GPP access procedure, the UE or network requested PDU session modification via non-3GPP access procedure (see
TS 23.502) .
During PDU session establishment, based on local policies, pre-configuration and the QoS profiles received:
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the N3IWF or the TNGF (depending on whether the UE is connected to untrusted non-3GPP access or trusted non-3GPP access, respectively):
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shall determine the number of IPsec child SAs to establish and the QoS profiles associated with each IPsec child SA; and
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shall then initiate IPsec SA creation procedure to establish child SAs associating to the QoS flows of the PDU session; or
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the W-AGF serving the 5G-RG:
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shall determine the number of W-UP resources to establish and the QoS profiles associated with each W-UP resource; and
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shall initiate creation of one or more W-UP resources using means out of scope of the present document. The W-AGF serving the 5G-RG shall associate each W-UP resource with a PDU session, zero or more QFIs, and optionally an indication of whether the W-UP resource is the default W-UP resource. For each W-UP resource, the 5G-RG becomes aware using means out of scope of the present document about association of the W-UP resource and the PDU session, the zero or more QFIs, and optionally the indication of whether the W-UP resource is the default W-UP resource.
In order to support QoS differentiation in case of access to PLMN services via an SNPN and access to SNPN services via a PLMN, the N3IWF is preconfigured with one or more QoS profiles requiring a dedicated IPsec child SA which can be associated with a DSCP value.
In order to support QoS differentiation in case of access to PLMN services via 5G ProSe layer-3 UE-to-network relay with N3IWF as specified in
clause 5.6.2.2 of TS 23.304, the N3IWF is preconfigured with one or more QoS profiles requiring a dedicated IPsec child SA which can be associated with a DSCP value.
For uplink of trusted and untrusted non-3GPP accesses, the UE associates an uplink user data packet with a QFI as specified in
TS 24.501. In both cases of untrusted non-3GPP access and trusted non-3GPP access, the UE shall then encapsulate the uplink user data packet and the QFI associated with the uplink user data packet in the GRE header and select IPsec child SA based on PDU session and QFI associated with the uplink user data packet as specified in
clause 8.3. In case of trusted non-3GPP access, the UE shall reserve non-3GPP access network QoS resources for the IPsec child SA according to the received Additional QoS Information when the selected IPsec child SA is established. In case of untrusted non-3GPP access, the UE may receive an Additional QoS Information from the N3IWF during IPsec child SA establishment. If the UE receives the Additional QoS Information from the N3IWF, the UE may reserve non-3GPP access network QoS resources for the IPsec child SA according to the received Additional QoS Information when the selected IPsec child SA is established.
For uplink of wireline access, the 5G-RG associates an uplink user data packet with a QFI as specified in
TS 24.501, shall select a W-UP resource based on the PDU session and the QFI associated with the uplink user data as specified in
clause 8.3 and shall transport the uplink user data packet via the selected W-UP resource using means out of scope of the present specification.
For downlink of trusted and untrusted non-3GPP accesses, the UPF maps the user data packet to a QoS flow. In case of untrusted non-3GPP access, the N3IWF shall determine the IPsec child SA to use for sending of the downlink user data packet over NWu based on mapping of the QoS flow to the IPsec child SA based on QFI of the QoS flow of the user data packet and the identity of the PDU session of the user data packet. In case of trusted non-3GPP access, the TNGF shall determine the IPsec child SA to use for sending of the downlink user data packet over NWt based on mapping of the QoS flow to the IPsec child SA based on QFI of the QoS flow of the user data packet and the identity of the PDU session of the user data packet. Furthermore, TNGF may reserve non-3GPP access network QoS resources for the IPsec child SA.
For downlink of wireline access, the UPF maps the user data packet to a QoS flow. In case of wireline access, the W-AGF serving the 5G-RG shall select a W-UP resource for a downlink user data packet based on mapping of the QoS flow to the W-UP resources, based on QFI of the QoS flow of the user data packet and the identity of the PDU session of the user data packet, and shall transport the downlink user data packet and the QFI associated with the downlink user data packet via the selected W-UP resource using means out of scope of the present specification.
Reflective QoS is also supported when the UE accesses the 5GCN via non-3GPP access network as specified in
TS 23.502. If the N3IWF for untrusted non-3GPP access or the TNGF for trusted non-3GPP access receives a downlink user packet associated with Reflective QoS Indicator (RQI), the N3IWF or the TNGF shall set the RQI in the GRE header when encapsulating the downlink user data packet into a GRE encapsulated user data packet as specified in
clause 8.3. If the W-AGF serving the 5G-RG receives a downlink user packet associated with Reflective QoS Indicator (RQI), the W-AGF shall transport the RQI together with the downlink user data packet and the QFI associated with the downlink user data packet via the selected W-UP resource over NWu, as described in
clause 4.4.2.3.
If the UE is provided with maximum flow bit rate (MFBR) for UL for a QFI as specified in
TS 24.501, the UE should send user data packets associated with the QFI with a bitrate lower than or equal to the maximum flow bit rate (MFBR) for UL.