ACCESS TRAFFIC STEERING, SWITCHING, SPLITTING (ATSSS) BETWEEN ACCESS PATHS CONNECTED TO AN EVOLVED PACKET CORE AND TO A 5G CORE IN WIRELESS COMMUNICATION SYSTEMS
FIELD OF TECHNOLOGY
[0001] The present disclosure relates to access traffic steering, switching, splitting (ATSSS) between access paths connected to an evolved packet core (EPC) and to a 5g core (5GC) in a wireless communication systems.
BACKGROUND
[0002] The present disclosure relates to the provisioning of multi-access protocol data unit (MA-PDU) connectivity service in communication networks, which protocol data units (PDUs) may be exchanged between a user equipment and a data network by simultaneously using one 3GPP access and one non-3GPP access of the communication network. The MA-PDU connectivity service may be realized by establishing a MA-PDU session, which is a PDU session that may have user-plane resources on two access networks: 3GPP and non-3GPP accesses. The process for determining which access a PDU is exchanged on is determined by the access traffic steering, switching, and splitting (ATSSS) feature of a communication network that is specified in 3GPP V16 TS 23.502 clause 5.32.
[0003] Developments in the provisioning of a MA-PDU connectivity service in communication networks are desirable.
SUMMARY
[0004] According to one aspect of an embodiment, the present disclosure provides a method for a user plane function (UPF) to provide data to a user equipment (UE) that includes receiving, from a session management function (SMF), rules associated with a packet forwarding control protocol (PFCP) session of a multi-access protocol data unit (MA-PDU) session in which a 5G core (5GC) access path connects a first access of the UE to the UPF via a 5GC and an evolved packet core (EPC) access path connects a second access of the UE to the UPF via an EPC, receiving a data packet from a data network, the data packet associated with the PFCP session of the MA-PDU session, determining which the 5GC access path or the EPC access path is to be used to transmit the data packet to the UE, when the 5GC access path is to be used to transmit the data packet, inserting 5GC-specific information in a header associated with the data packet and transmitting the data packet, with the 5GC-specific information, via the 5GC access path, and when the EPC access path is to be used to transmit the data packet, transmitting the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information.
[0005] In an example, the rules received from the SMF include a forwarding action rule (FAR) having a forwarding parameter, wherein the forwarding parameter is a destination interface type that indicates an interface of the UPF to be used to transmit the data packet, the indicated interface being associated with either the 5GC access path or the EPC access path, or a system type that indicates whether the access path to be used to transmit the data packet travels through the EPC or only travels through the 5GC, and determining which one of the 5GC access path and the EPC access path is to be used to transmit the data packet is performed based on the forwarding parameter of the FAR.
[0006] In an example, the rules received from the SMF include a conditional rule included in quality of service enforcement rule (QER) that instructs the UPF to insert 5GC-specific information in a header associated with the data packet only in response to determining that the data packet is to be transmitted on the 5GC access path.
[0007] In an example, the rules received by the UPF from the SMF include a first QER that apply to data packets to be transmitted on the 5GC access path and that instruct the UPF to insert the 5GC-specific information into the header associated with the data packet, and a second QER that apply to data packets to be transmitted on the EPC access path and that instruct the UPF not to insert the 5GC-specific information into the header associated with the data packet, and inserting the 5GC-specific information in the header associated with the data packet and transmitting the data packet with the 5GC-specific information via the 5GC access path comprises applying the first QER to the data packet prior to transmitting the data packet on the 5GC access path, and transmitting the data packet via the EPC access path, wherein the header associated with° the data packet transmitted via the EPC access path does not include the 5GC-specific information, comprises applying the second QER to the data packet prior to transmitting the data packet on the EPC access path.
[0008] In an example, receiving the rules from the SMF comprises receiving a forwarding action rule (FAR) associated with the EPC access path instructing the UPF to remove any 5GC-specific information in the header associated with any data packet to be transmitted on the EPC access path, and transmitting the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information, comprises applying the FAR by removing the 5GC-specific information from the header associated with the data packet prior to transmitting the data packet.
[0009] In an example, the 5GC-specific information associated with the data packet includes at least one of a quality of service flow identifier (QFI), a reflective quality of service indicator (RQI), and a paging policy indicator (PPI), and the header associated the data packet is a GTP-U protocol data unit (PDU) session container header of a GTP-U session container that includes the data packet.
[0010] According to another aspect of an embodiment, the present disclosure provides method for a session management function (SMF) for a multi-access protocol data unit (MA-PDU) session that includes transmitting to a user plane function (UPF) rules associated with a packet forwarding control protocol (PFCP) session of the MA-PDU session in which a 5G core (5GC) access path connects a first access of a UE to the UPF via a 5GC and an evolved packet core (EPC) access path connects a second access of the UE to the UPF via an EPC, wherein, for a data packet associated with the PFCP session of the MA-PDU session that is received at the UPF from a data network, the rules instruct the UPF to determine which the 5GC access path or the EPC access path is to be used to transmit the data packet to the UE, when the data packet is to be transmitted on the 5GC access path, insert 5GC-specific information in a header associated with the data packet and transmit the data packet, with the 5GC-specific information via the 5GC access path, and when the data packet is to be transmitted on the EPC access path, transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information.
[0011] In an example, the rules include a forwarding action rule (FAR) having a forwarding parameter, wherein the forwarding parameter is a destination interface type that indicates an interface of the UPF to be used to transmit the data packet, the indicated interface being associated with either the 5GC access path or the EPC access path, or a system type that indicates whether the access path to be used to transmit the data packet travels through the EPC or only travels through the 5GC, and the rules instructing the UPF to determine which one of the 5GC access path and the EPC access path is to be used to transmit the data packet comprise the rules instructing the UPF to perform the determining based on the forwarding parameter of the FAR.
[0012] In an example, the rules include a conditional rule included in a quality of service enforcement rule (QER) that instructs the UPF to insert 5GC-specific information only when the data packet is to be transmitted on the 5GC access path is satisfied.
[0013] In an example, the rules include a first quality of service enforcement rule (QER) that applies only to data packets to be transmitted on the 5GC access path and that instructs the UPF to insert the 5GC-specific information into the header associated with the data packet, and a second QER that applies only to data packets to be transmitted on the EPC access path and that instructs the UPF not to insert the 5GC-specific information into the header associated with the data packet, or to remove any 5GC-specific information included in the header associated with the data packet.
[0014] In an example, the rules comprise a forwarding action rule (FAR) associated with the EPC access path that instructs the UPF to remove any 5GCspecific information in the header associated with any data packet to be transmitted on the EPC access path.
[0015] In an example, the 5GC-specific information associated with the data packet includes at least one of a quality of service flow identifier (QFI), a reflective quality of service indicator (RQI), and a paging policy indicator (PPI), and the header associated the data packet is a GTP-U protocol data unit (PDU) session container header of a GTP-U session container that includes the data packet.
[0016] According to another aspect of an embodiment, the present disclosure provides an apparatus that includes at least one processor, and at least one memory storing instructions of a user plane function (UPF), wherein when the instructions are executed by the at least one processor, cause the apparatus to receive, from a session management function (SMF), rules associated with a packet forwarding control protocol (PFCP) session of a multi-access protocol data unit (MA-PDU) session in which a 5G core (5GC) access path connects a first access of the UE to the UPF via a 5GC and an evolved packet core (EPC) access path connects a second access of the UE to the UPF via an EPC, receive a data packet from a data network, the data packet associated with the PFCP session of the MA-PDU session, determine which the 5GC access path or the EPC access path is to be used to transmit the data packet to the UE, when the 5GC access path is to be used to transmit the data packet, insert 5GC-specific information in a header associated with the data packet and transmit the data packet, with the 5GC-specific information, via the 5GC access path, and when the EPC access path is to be used to transmit the data packet, transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information.
[0017] In an example, the rules received from the SMF include a forwarding action rule (FAR) having a forwarding parameter, wherein the forwarding parameter is a destination interface type that indicates an interface of the UPF to be used to transmit the data packet, the indicated interface being associated with either the 5GC access path or the EPC access path, or a system type that indicates whether the access path to be used to transmit the data packet travels through the EPC or only travels through the 5GC, and the instructions that, when performed by the processor of the apparatus cause the apparatus to determine which one of the 5GC access path and the EPC access path is to be used to transmit the data packet comprise instructions that, when performed by the processor of the apparatus cause the apparatus to determine which one of the 5GC access path and the EPC access path is to be used to transmit the data packet based on the forwarding parameter of the FAR.
[0018] In an example, the rules received from the SMF include a conditional rule included in quality of service enforcement rule (QER) that instructs the UPF to insert 5GC-specific information in a header associated with the data packet only in response to determining that the data packet is to be transmitted on the 5GC access path.
[0019] In an example, the rules received by the UPF from the SMF include a first QER that apply to data packets to be transmitted on the 5GC access path and that instruct the UPF to insert the 5GC-specific information into the header associated with the data packet, and a second QER that apply to data packets to be transmitted on the EPC access path and that instruct the UPF not to insert the 5GC-specific information into the header associated with the data packet, and the instructions that, when performed by the processor of the apparatus cause the apparatus to insert the 5GC-specific information in the header associated with the data packet and transmit the data packet with the 5GC-specific information via the 5GC access path comprises instructions that, when performed by the processor of the apparatus cause the apparatus to apply the first QER to the data packet prior to transmitting the data packet on the 5GC access path, and the instructions that, when performed by the processor of the apparatus cause the apparatus to transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information, comprise instructions that, when performed by the processor of the apparatus cause the apparatus to applying the second QER to the data packet prior to transmitting the data packet on the EPC access path.
[0020] In an example, the rules received from the SMF comprise a forwarding action rule (FAR) associated with the EPC access path instructing the UPF to remove any 5GC-specific information in the header associated with any data packet to be transmitted on the EPC access path, and the instructions that, when performed by the processor of the apparatus cause the apparatus to transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information, comprises instructions that, when performed by the processor of the apparatus cause the apparatus to apply the FAR by removing the 5GC-specific information from the header associated with the data packet prior to transmitting the data packet.
[0021] In an example, the 5GC-specific information associated with the data packet includes at least one of a quality of service flow identifier (QFI), a reflective quality of service indicator (RQI), and a paging policy indicator (PPI), and the header associated the data packet is a GTP-U protocol data unit (PDU) session container header of a GTP-U session container that includes the data packet.
[0022] According to another aspect of an embodiment, the present disclosure provides a computer-readable medium storing instructions of a user plane function (UPF), wherein when the instructions are executed by at least one processor of an apparatus, cause the apparatus to receive, from a session management function (SMF), rules associated with a packet forwarding control protocol (PFCP) session of a multi-access protocol data unit (MA-PDU) session in which a 5G core (5GC) access path connects a first access of the UE to the UPF via a 5GC and an evolved packet core (EPC) access path connects a second access of the UE to the UPF via an EPC, receive a data packet from a data network, the data packet associated with the PFCP session of the MA-PDU session, determine which the 5GC access path or the EPC access path is to be used to transmit the data packet to the UE, when the 5GC access path is to be used to transmit the data packet, insert 5GC-specific information in a header associated with the data packet and transmit the data packet, with the 5GC-specific information, via the 5GC access path, and when the EPC access path is to be used to transmit the data packet, transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information.
[0023] In an example, the rules received from the SMF include a forwarding action rule (FAR) having a forwarding parameter, wherein the forwarding parameter is a destination interface type that indicates an interface of the UPF to be used to transmit the data packet, the indicated interface being associated with either the 5GC access path or the EPC access path, or a system type that indicates whether the access path to be used to transmit the data packet travels through the EPC or only travels through the 5GC, and the instructions that, when performed by the processor of the apparatus cause the apparatus to determine which one of the 5GC access path and the EPC access path is to be used to transmit the data packet comprise instructions that, when performed by the processor of the apparatus cause the apparatus to determine which one of the 5GC access path and the EPC access path is to be used to transmit the data packet based on the forwarding parameter of the FAR.
[0024] In an example, the rules received from the SMF include a conditional rule included in quality of service enforcement rule (QER) that instructs the UPF to insert 5GC-specific information in a header associated with the data packet only in response to determining that the data packet is to be transmitted on the 5GC access path.
[0025] In an example, the rules received by the UPF from the SNIF include a first QER that apply to data packets to be transmitted on the 5GC access path and that instruct the UPF to insert the 5GC-specific information into the header associated with the data packet, and a second QER that apply to data packets to be transmitted on the EPC access path and that instruct the UPF not to insert the 5GC-specific information into the header associated with the data packet, and the instructions that, when performed by the processor of the apparatus cause the apparatus to insert the 5GC-specific information in the header associated with the data packet and transmit the data packet with the 5GC-specific information via the 5GC access path comprises instructions that, when performed by the processor of the apparatus cause the apparatus to apply the first QER to the data packet prior to transmitting the data packet on the 5GC access path, and the instructions that, when performed by the processor of the apparatus cause the apparatus to transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information, comprise instructions that, when performed by the processor of the apparatus cause the apparatus to applying the second QER to the data packet prior to transmitting the data packet on the EPC access path.
[0026] In an example, the rules received from the SMF comprise a forwarding action rule (FAR) associated with the EPC access path instructing the UPF to remove any 5GC-specific information in the header associated with any data packet to be transmitted on the EPC access path, and the instructions that, when performed by the processor of the apparatus cause the apparatus to transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GCspecific information, comprises instructions that, when performed by the processor of the apparatus cause the apparatus to apply the FAR by removing the 5GC-specific information from the header associated with the data packet prior to transmitting the data packet.
[0027] In an example, the 5GC-specific information associated with the data packet includes at least one of a quality of service flow identifier (QFI), a reflective quality of service indicator (RQI), and a paging policy indicator (PPI), and the header associated the data packet is a GTP-U protocol data unit (PDU) session container header of a GTP-U session container that includes the data packet.
[0028] According to another aspect of an embodiment, the present disclosure provides the present disclosure provides an apparatus that includes at least one processor, and at least one memory storing instructions of a user plane function (UPF), wherein when the instructions are executed by the at least one processor, cause the apparatus to transmit to a user plane function (UPF) rules associated with a packet forwarding control protocol (PFCP) session of a multi-access MAPDU session in which a 5G core (5GC) access path connects a first access of a user equipment (UE) to the UPF via a 5GC and an evolved packet core (EPC) access path connects a second access of the UE to the UPF via an EPC, wherein, for a data packet associated with the PFCP session of the MA-PDU session that is received at the UPF from a data network, the rules instruct the UPF to determine which the 5GC access path or the EPC access path is to be used to transmit the data packet to the UE, when the data packet is to be transmitted on the 5GC access path, insert 5GC-specific information in a header associated with the data packet and transmit the data packet, with the 5GC-specific information via the 5GC access path, and when the data packet is to be transmitted on the EPC access path, transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information.
[0029] In an example, the rules include a forwarding action rule (FAR) having a forwarding parameter, wherein the forwarding parameter is a destination interface type that indicates an interface of the UPF to be used to transmit the data packet, the indicated interface being associated with either the 5GC access path or the EPC access path, or a system type that indicates whether the access path to be used to transmit the data packet travels through the EPC or only travels through the 5GC, and the rules instructing the UPF to determine which one of the 5GC access path and the EPC access path is to be used to transmit the data packet comprise the rules instructing the UPF to perform the determining based on the forwarding parameter of the FAR.
[0030] In an example, the rules include a conditional rule included in a quality of service enforcement rule (QER) that instructs the UPF to insert 5GC-specific information only when the data packet is to be transmitted on the 5GC access path is satisfied.
[0031] In an example, the rules include a first quality of service enforcement rule (QER) that applies only to data packets to be transmitted on the 5GC access path and that instruct the UPF to insert the 5GC-specific information into the header associated with the data packet, and a second QER that applies only to data packets to be transmitted on the EPC access path and that instruct the UPF not to insert the 5GC-specific information into the header associated with the data packet, or to remove any 5GC-specific information included in the header associated with the data packet.
[0032] In an example, the rules comprise a forwarding action rule (FAR) associated with the EPC access path that instructs the UPF to remove any 5GCspecific information in the header associated with any data packet to be transmitted on the EPC access path.
[0033] In an example, the 5GC-specific information associated with the data packet includes at least one of a quality of service flow identifier (QFI), a reflective quality of service indicator (RQI), and a paging policy indicator (PPI), and the header associated the data packet is a GTP-U protocol data unit (PDU) session container header of a GTP-U session container that includes the data packet.
[0034] According to another aspect of an embodiment, the present disclosure provides the present disclosure provides a computer-readable medium storing instructions of a session management function (SMF), wherein when the instructions are executed by at least one processor of an apparatus, cause the apparatus to transmit to a user plane function (UPF) rules associated with a packet forwarding control protocol (PFCP) session of a multi-access MA-PDU session in which a 5G core (5GC) access path connects a first access of a user equipment (UE) to the UPF via a 5GC and an evolved packet core (EPC) access path connects a second access of the UE to the UPF via an EPC, wherein, for a data packet associated with the PFCP session of the MA-PDU session that is received at the UPF from a data network, the rules instruct the UPF to determine which the 5GC access path or the EPC access path is to be used to transmit the data packet to the UE, when the data packet is to be transmitted on the 5GC access path, insert 5GC-specific information in a header associated with the data packet and transmit the data packet, with the 5GC-specific information via the 5GC access path, and when the data packet is to be transmitted on the EPC access path, transmit the data packet via the EPC access path, wherein the header associated with the data packet transmitted via the EPC access path does not include the 5GC-specific information.
[0035] In an example, the rules include a forwarding action rule (FAR) having a forwarding parameter, wherein the forwarding parameter is a destination interface type that indicates an interface of the UPF to be used to transmit the data packet, the indicated interface being associated with either the 5GC access path or the EPC access path, or a system type that indicates whether the access path to be used to transmit the data packet travels through the EPC or only travels through the 5GC, and the rules instructing the UPF to determine which one of the 5GC access path and the EPC access path is to be used to transmit the data packet comprise the rules instructing the UPF to perform the determining based on the forwarding parameter of the FAR.
[0036] In an example, the rules include a conditional rule included in a quality of service enforcement rule (QER) that instructs the UPF to insert 5GC-specific information only when the data packet is to be transmitted on the 5GC access path is satisfied.
[0037] In an example, the rules include a first quality of service enforcement rule (QER) that applies only to data packets to be transmitted on the 5GC access path and that instruct the UPF to insert the 5GC-specific information into the header associated with the data packet, and a second QER that applies only to data packets to be transmitted on the EPC access path and that instruct the UPF not to insert the 5GC-specific information into the header associated with the data packet, or to remove any 5GC-specific information included in the header associated with the data packet.
[0038] In an example, the rules comprise a forwarding action rule (FAR) associated with the EPC access path that instructs the UPF to remove any 5GCspecific information in the header associated with any data packet to be transmitted on the EPC access path.
[0039] In an example, the 5GC-specific information associated with the data packet includes at least one of a quality of service flow identifier (QFI), a reflective quality of service indicator (RQI), and a paging policy indicator (PPI), and the header associated the data packet is a GTP-U protocol data unit (PDU) session container header of a GTP-U session container that includes the data packet.
[0040] The term "non-transitory," as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] Embodiments of the present disclosure will now be described, by way of example only, with reference to the attached figures.
[0042] FIG. 1 is a schematic diagram showing a communication network configured to provide multi-access protocol data unit connectivity service.
[0043] FIG. 2 is a schematic diagram showing packet forwarding control protocol implemented in accordance with aspects of the embodiments.
[0044] FIG. 3 is a schematic diagram showing a communication network configured to provide multi-access protocol data unit connectivity service when a 5 3GPP access is connected to an evolved packet core and a non-3GPP access is connected to a 5G core in accordance with aspects of the embodiments.
[0045] FIG. 4 is a schematic diagram showing a communication network configured to provide multi-access protocol data unit connectivity service when a non-3GPP access is connected to an evolved packet core and a 3GPP access is 10 connected to a 5G core in accordance with aspects of the embodiments.
[0046] FIG. 5 is a flowchart showing a method in accordance with example embodiments.
[0047] FIG. 6 is a schematic diagram showing packet forwarding control protocol implemented in accordance with an example embodiment.
[0048] FIG. 7 is a schematic diagram illustrating various physical and logical components of an apparatus in accordance with an example embodiment.
DETAILED DESCRIPTION
[0049] For simplicity and clarity of illustration, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.
Numerous details are set forth to provide an understanding of the examples described herein. The examples may be practiced without these details. In other instances, well-known methods, procedures, and components are not described in detail to avoid obscuring the examples described. The description is not to be considered as limited to the scope of the examples described herein.
[0050] The present disclosure relates to provisioning of a multi-access protocol data unit (MA-PDU) connectivity service in a communication network. A MA-PDU connectivity service may be provisioned by establishing a MA-PDU session having user-plane resources on two different access networks, when one access is connected to the 5G core (5GC) and the other access is connected to the evolved packet core (EPC). For example, the MA-PDU session may include a 3GPP access connected to a 5G core (5GC) of a 5G network and a non-3GPP access connected to an evolved packet core (EPC) of a 4G network, or, alternatively, may have a 3GPP access connected to an EPC and a non-3GPP access connected to a 5GC. The process used by the MA-PDU connectivity service to determine which access a PDU is exchanged on during a MA-PDU session is determined by the access traffic steering, switching, and splitting (ATSSS) feature as described in 3GPP V16 TS 23.502 clause 5.32.
[0051] Reference is first made to FIG. 1, which shows a schematic representation of a communication network 100 that is configured to provide MAPDU connectivity service such that a user equipment (UE) 102 may communicate with application servers (not shown) hosting third party application functions (not shown) via data network (DN) 104. The communication network 100 includes a 3GPP access 106, a non-3GPP access 108, and a core network 110 (e.g., a 5G core network (5GC)) that operate based on the 5th generation radio access technology described in the 31d Generation Partnership Project (3GPP) standard for new radio.
[0052] The 3GPP access 106 in the example communication network 100 may 20 comprise a radio access (RAN) comprising one or more radio access (RAN) nodes (not shown), otherwise referred to as base stations. Examples of a radio access nodes include, but are not limited to, an eNodeB and a gNodeB (gNB).
[0053] The non-3GPP access 108 may include any trusted or untrusted non3GPP accesses such as, for example, Vt/i-Fi, WiMAX, and wireline access, which can communication with the core network via an interworking function.
[0054] The core network 110 comprises a plurality of network functions, including, inter alia, an access and mobility function (AMF) 112, a session management function (SMF) 114, a policy control function (PCF) 116, and a user plane function (UPF) 118. Other network functions of the core network 110 are not illustrated for ease of illustration but would be understood by a person skilled in the art. The functionalities of the network functions of the core network 110 are known to a person skilled in the art and hence are not described in detail.
[0055] An access traffic steering, switching, splitting (ATSSS) feature, specified in 3GPP V16.0 TS 23.502 clause 5.32, enables an MA-PDU connectivity service in 5 the communication network 100 in which PDU5 can be exchanged between the UE 102 and the DN 104 by simultaneously using the 3GPP access 106 and the non-3GPP access 108 and two independent tunnels between the UPF 118 and the 3GPP access 106 and the non-3GPP access 108 (labelled as N3 in FIG. 1). The MA-PDU connectivity service is realized by establishing a MA-PDU session, i.e. a 10 PDU Session that may have user-plane resources on two accesses.
[0056] The ATSSS feature according to the current 3GPP standard for 5GC enables MA-PDU sessions only when the 3GPP access and the non-3GPP access are both connected to a 5GC.
[0057] For any PDU Session, the SMF 114 establishes a packet forwarding control protocol (PFCP) session in the UPF 118. Based on the PFCP protocol defined in 3GPP TS 29.244, the SMF 114 provides the UPF 118 with a set of rules, such as Packet Detection Rules (PDRs), Quality of Service (QoS) Enforcement Rules (QERs), Usage Reporting Rules (URR5), FARs (Forwarding Action Rules), and, in the case of a MA-PDU session, Multi-Access Rules (MARs), for that PCFP session. The PDR5 contain traffic filters (e.g., source/destination IP address and port, specific application), e.g. identifying specific service data flows, against which DL packets received by the UPF are matched.
[0058] The association of each PDR with one or more QERs, a FAR, one or more URRs and a MAR provide instructions that the UPF 118 applies to all PDU5 received by the UPF 118 that are associated with that PCFP session and that match a specific PDR. PDR5 are associated with QER(s), FAR, URR(s) and MAR by including in the PDR description the QER Identifier (ID)s, FAR ID, URR ID(s) and MAR ID. MARs were specifically introduced in 3GPP V16.0 TS 23.502 clause 5.32.1 to provide ATSSS functionality. The MARS indicates to the UPF 118 how to distribute downlink (DL) traffic (matching one or more DL PDRs), which is traffic (e.g., DL data packets) received from the DN 106 and to be sent by the UPF 118 to the UE 102, via the 3GPP access 106 and non-3GPP access 108.
[0059] The UPF 118 and the SMF 114 may each be implemented, separately or together, by a combination of hardware processing circuit and software and/or firmware comprising machine-readable instructions that are executable by the hardware processing circuit, or software comprising machine-readable instructions that are executable by a hardware processing circuit of an apparatus. A hardware processing circuit includes at least one processor comprising machine-readable instructions that are executable by the hardware processing circuit and at least one memory storing the machine-readable instructions. A processor includes any or some combination of an accelerator, microprocessor, a core of a multi-core microprocessor, a microcontroller, a programmable integrated circuit, a programmable gate array, a digital signal processor, a central processing unit, a graphic processing unit, a tensor processing unit. Memory includes any or some combination of volatile or non-volatile memory (e.g., a flash memory, cache, a random-access memory (RAM), and/or a read-only memory (ROM)). The memory stores the machine-executable instructions of the software and/or firmware for execution by the at least one processor of the hardware processing circuit. The machine-executable instructions are executable by the hardware processing circuit to perform the actions or operations of the methods of the UPF 118 described herein.
[0060] Referring now to FIG. 2, a schematic diagram illustrating how the UPF 118 determines and applies the applicable PDR to a DL data packet is shown.
The UPF 118 is connected to the SMF 114, which establishes (or modifies) a PFCP session by sending a PFCP Session Establishment Request (or a PFCP Session Modification Request) to the UPF 118 including the appropriate PDRs, QER5, FAR5, URRs and MARs associated with that PCFP session.
[0061] The example UPF 118 shown in FIG. 2 includes a PFCP session look up 30 function 202, a PFCP session PDR look up function 204, one or more PDRs 206a- 206N received from the SMF 114, each of the PDR5 206a-206N associated with a respective PFCP session.
[0062] In the example shown in FIG. 2, a DL data packet associated with a multi-access PDU session is received at the UPF 118 from a data network (not shown), such as data network 106 of the communication network 100. A PFCP session associated with the DL packet is determined by the PFCP session look up function 202. A particular one of the PDRs 206a-206N that is associated with the determined PFCP session, for example PDR 206b, is determined by the PFCP session PDR look up function 204. The determination of the PDR 206a-206N of the PFCP session that matches the DL packet includes determining the PDR 206a-206N that matches the DL packet with the highest precedence. The PDR 206b, which is associated with a multi-access rule (MAR) 208, forwarding action rule (FAR) 210, one or more quality of service enforcement rules (QERs) 212, and zero, one or more usage reporting rules (URRs) 214, are applied by the UPF 118 to the DL data packet. After the applying the PDR 206b, the UFP 118 transmits the DL data packet to either the 3GPP access or the non-GPP access network, as determined in accordance with the MAR 208.
[0063] In a MA-PDU session, each MAR refers to two FARs: one associated with a tunnel for the 3GPP access network, and one associated with a tunnel for 20 the non-3GPP access. The tunnels may be general packet ratio service (GPRS) tunnelling protocol user-plane (GTP-U) tunnels.
[0064] The UE and the UPF may perform access performance measurements in order to estimate the Round-Trip Time (RTT) and/or the Packet Loss Rate (PLR) that is expected for a Service Data Flow (SDF) when traffic of the SDF is transmitted via 3GPP access and when traffic of the SDF is transmitted via non3GPP access. Based on these measurements and the provisioned ATSSS rules in the UE and MAR rules in the UPF, the UPF decides how to distribute downlink traffic of an SDF for transmission through the two accesses: the 3GPP access and the non-GPP access.
[0065] In a SGC, traffic of a SDF is mapped to a Quality of Service (QoS) flow, which is the finest granularity for QoS forwarding treatment in the SGC. All traffic mapped to the same QoS flow receives the same forwarding treatment, such as, for example, scheduling policy, queue management policy, rate shaping policy, RLC configuration. Providing different QoS forwarding treatment for different traffic requires the different traffic be mapped to different QoS Flow.
[0066] A QoS Flow ID (QFI) is used to identify a QoS Flow in the 5G System.
User Plane traffic with the same QFI within a PDU Session receives the same traffic forwarding treatment (e.g. scheduling, admission threshold).
[0067] Conventionally, the DL data packet is transmitted by the UPF 118 transmits as the payload a GTP-U PDU session container, which may be referred to herein as "session container" or "PDU session container", having a GTP-U PDU session container header, which may be referred to herein as "session container header" or "PDU session container header".
[0068] The UPF 118 inserts the QFI value of the QoS flow associated with the DL data packet in a GTP-U extension header of the PDU session container header, prior to sending the GTP-U session container, which includes DL data packet as payload, via either of the accesses (3GPP access 106 and non-3GPP access 108 in FIG. 1) for all PDU session types. In the present disclosure, any references to the UPF sending a data packet is understood to mean sending a PDU session container that includes the data packet as payload, and reference to inserting 5GC-specific information in a header of a data packet is understood to mean inserting the 5GC-specific information in a PDU session container header of the PDU session container that includes the data packet as payload.
[0069] Within the 5GS, a QoS flow of the MA-PDU session is controlled by the SMF 114 and may be preconfigured, or established during the PDU session establishment procedure, or the PDU session modification procedure.
[0070] Conventionally, the UFP 118 is instructed to insert the QFI value of DL data packets into a PDU session container header of a PDU session container that includes the DL data packet as payload by applying "QoS Flow ID" included in the QERs that are received from the SMF 114. The PDU session container header contains control information elements that a NG-RAN may utilize to the transfer the packet.
[0071] The following table shows an example of QERs that define how a packet is to be processed by the UPF 118 in terms of bit rate limitation and packet marking for QoS purposes.
Attribute Description Comment
N4 Session ID Identifies the N4 session associated to this QER Rule ID Unique identifier to identify this information.
QoS Enforcement Rule correlation ID (NOTE 1) An identity allowing the UP function to correlate multiple Sessions for the same UE and APN. Is used to correlate QoS Enforcement Rules for APNAMBR enforcement.
Gate status UL/DL Instructs the UP function to let the flow pass or to block the flow. Values are: open, close, close after measurement report (for termination action "discard").
Maximum bitrate The uplink/downlink maximum bitrate to be enforced for the packets. This field may e.g. contain any one of: - APN-AMBR (for a QER that is referenced by all relevant Packet Detection Rules of all PDN Connections to an APN) (NOTE 1).
- Session-AMBR (for a QER that is referenced by all relevant Packet Detection Rules of the PDU Session) - QoS Flow MBR (for a QER that is referenced by all Packet Detection Rules of a QoS Flow) - SDF MBR (for a QER that is referenced by the uplink/downlink Packet Detection Rule of a SDF) - Bearer MBR (for a QER that is referenced by all relevant Packet Detection Rules of a bearer) (NOTE 1).
Guaranteed bitrate The uplink/downlink guaranteed bitrate authorized for the packets. This field contains: - QoS Flow GBR (for a QER that is referenced by all Packet Detection Rules of a QoS Flow) - Bearer GBR (for a QER that is referenced by all relevant Packet Detection Rules of a bearer) (NOTE 1).
Averaging window The time duration over which the Maximum and Guaranteed bitrate shall be calculated This is for counting the packets received during the time duration.
Attribute Description Comment
Down-link flow level marking Flow level packet marking in the downlink. For UPF, this is for controlling the setting of the RQI in the encapsulation header as described in clause 5.7.5.3.
QoS Flow ID QoS Flow ID to be inserted by the UPF. The UPF inserts the OH value in the tunnel header of outgoing packets.
Paging Policy Indicator Indicates the PPI value the UPF is required to insert in outgoing packets (see clause 5.4.3.2). PPI applies only for DL traffic.
The UPF inserts the PPI in the outer header of outgoing PDU.
Packet rate (NOTE 1) Number of packets per time interval to be enforced. This field contains any one of - downlink packet rate for Serving PLMN Rate Control (the QER is referenced by all PDRs of the UE belonging to PDN connections using CloT EPS Optimisations as described in TS 23.401 [26]).
- uplink/downlink packet rate for APN Rate Control (the QER is referenced by all PDRs of the UE belonging to PDN connections to the same APN using CloT EPS Optimisations as described in TS 23.401 [26]).
End of Data Burst Marking Indication Indicates to the UPF to provide an End of Data Burst indication of the last PDU of a Data burst to the NG-RAN over GTP-U NG-RAN can configure UE power management schemes like connected mode DRX when UPF provides an indication of the End of Data Burst, see clause 5.37.8.3.
PDU Set Information marking Indicator Indicates the UPF to insert PDU Set Information related to packets belonging to a PDU Set into GTP-U header. UPF identifies PDU Sets in DL traffic and forwards PDU Set related information of each PDU to the NG-RAN over GTP-U, as described in clause 5.37.5.
NOTE 1: This parameter is only used for interworking with EPC.
[0072] The following shows an example PDU session container header of a PDU session container that includes a DL data packet payload in which the header includes a QFI inserted by the UPF 118: [0073] The above-described process for provisioning a MA-PDU connectivity service enables for MA-PDU sessions in which both the 3GPP access 106 and the non-3GPP access 108 are connected to a SGC.
[0074] The ATSSS feature according to the current 3GPP standard for 5GC enables MA-PDU sessions only when the 3GPP access and the non-3GPP access are both connected to a 5GC. However, the conventional ATSSS feature according to the current 3GPP standard for 5GC does not enable MA-PDU sessions when one access is connected to a SGC, and the other access is connected to an EPC, for example, when the 3GPP access is connected to an EPC and the non-3GPP access is connected to a 5GC, or when the 3GPP access is connected to a 5GC and the non-3GPP access is connected to an EPC.
[0075] For example, using the convention ATSSS feature according to the current 3GPP standard for 5GC when one access is connected to a 5GC and the other access is connected to an EPC will result in errors when a DL packet is sent together with 5GC-specific information, such as in a PDU session container having a PDU session container header that includes the QFI as described previously, are transmitted by the UPF to an EPC.
[0076] FIG. 3 shows a schematic diagram of an example communication network 300 configured such that a UE 302 exchanges data with a data network 0 or 1 0-3 Padding
PPP I ROI I
QoS Flow Identifier 0 or 8 DL Sending Time Stamp 0 or 3 DL QFI Sequence Number 0 or 4 DL MBS QFI Sequence Number
PPI Spare
PDU Type (=0)
QMP
SNP
MSNP Spare
(not shown) via a 3GPP access 304 and an EPC connected to the 3GPP access 304 and via a non-3GPP access 306 and a 5GC connected to the non-3GPP access 306. The 5GC includes a common user plane anchor point for the data network, which is provided by the session management function plus packet data network gateway control plane function (SN1F+PGW-C) 308 and the user plane function plus PGW user plane function (UPF+PGW-U) 310. The communication network 300 also includes a combined home subscriber server and unified data management (illustrated as HSS+UDM) 312.
[0077] Although the example communication network 300 shown includes various functionalities of the 4G and 5G networks provided by a single co-located, or combined, functionality, i.e., the SMF+PGW-C 308, UPF+PGW-U 310, and the HSS+UDM 312, in practice, the network functionalities may be provided separately, or not co-located.
[0078] In communication network 300, the 3GPP access 304 includes an evolved-UNITS Terrestrial Access (E-UTRAN) 314 and the non-3GPP access 306 includes a non-3GPP interworking function/trusted non-3GPP gateway function (N3IWF/TNGF) 316 to support non-trusted and trusted non-3GPP access, respectively. The communication network 300 includes a mobility management entity (MME) 318, serving gateway (SGW) 320, PCF 322, and AMF 324.
[0079] In the communication network 300, data packets from a data network (not shown) are received at the UPF+PGW-U 310, where the UPF functionality of the UPF+PGW-U 310 determines which of the 3GPP access 304 or the non-3GPP access 306 is to be used to transmit the data packet to the UE 302. This determination is made in accordance with the PDRs that apply to the particular PFCP session associated with the DL data packets as described previously.
[0080] In the present disclosure, the path that a data packet is sent along when sent to a UE via an access connected to the EPC is referred to as an "EPC access path", and the path that a data packet is sent along when sent to a UE via an access connected to a 5GC is referred to herein as a "5GC access path". In the present disclosure, the terms "access tunnel", "access pathway", "access branch" may be used interchangeably with, and are equivalent to, "access path" in order to identify which access path, i.e., through the EPC or through the 5GC only, is used by the UPF to transmit the data packet to the UE.
[0081] In the example communication network 300, if the determination is that the data packets are to be transmitted via the 3GPP access 304, which is connected to the EPC in the communication network 300, then the data packet is sent along the EPC access path of the communication network 300 from the UPF+PGW-U 310 to the SGW 320, then from the SGW 320 to the E-UTRAN 314, then from the E-UTRAN 314 to the UE 302.
[0082] If the determination is that the data packets are to be transmitted via the non-3GPP access 306, which is connected to the 5GC in the communication network 300, then the data packet is sent along the 5GC access path from the UPF+PGW-U 310 to the N3IWF/TNGF 316, then from the N3IWF/TNGF 316 to the UE 302.
[0083] FIG. 4 shows a schematic diagram of an example communication network 400 configured such that a UE 402 is connected to an EPC via a non3GPP access 404 and connected to a 5GC via a 3GPP access 406. Similar to the example communication network 300, the 5GC of the communication network 400 includes a common SMF+PGW-C 408, UPF+PGW-U 410, and HSS+UDM 412.
[0084] Similar to the communication network 300, although the example communication network 400 shown includes various functionalities of the 4G and 5G networks provided by a single co-located, or combined, functionality, i.e., the SMF+PGW-C 408, UPF+PGW-U 410, and the HSS+UDM 412, in practice, the network functionalities may be provided separately, i.e., not co-located.
[0085] In communication network 400, the non-3GPP access 304 includes an evolved packet data gateway (ePDG) 414 and the 3GPP access includes a next generation radio access (NG-RAN) 416. The communication network 400 includes a 3GPP authentication, authorization, and accounting (AAA) server 418, [0086] Similar to the example communication network 300 described previously, in the communication network 400, data packets from a data network (not shown) are received at the UPF+PGW-U 410, where the UPF functionality of the UPF+PGW-U 410 determines which of the 3GPP access 406 or the non-3GPP access 404 is to be used to transmit the data packet to the UE 402. This determination is made in accordance with the PDR5 that apply to the particular PFCP session associated with the DL data packets, as described previously.
[0087] In the example communication network 400, if the determination is that the data packets are to be transmitted via the non-3GPP access 404, which is connected to the EPC in the communication network 400, then the data packet is sent along the EPC access path of the communication network 400 from the UPF+PGW-U 310 to the ePDG 414, then from the ePDG 414 the UE 402.
[0088] If the determination is that the data packets are to be transmitted via the 3GPP access 406, which is connected to the 5GC in the communication network 400, then the data packet is sent along the 5GC access path of the communication network 400 from the UPF+PGW-U 410 to the NG-RAN 416, then from the NG-RAN 416 to the UE 402.
[0089] The functionalities of the network functions and other components of communication networks 300 and 400 shown in FIGS. 3 and 4, respectively, are known to a person skilled in the art and hence are not described in detail. In schematic diagrams of the example communication networks 300 and 400 in FIGS. 3 and 4, the elements associated with providing EPC access are shown shaded in grey for ease of reference only.
[0090] The UPF functionality included in UPF+PGW-U 310 and 410 may be substantially similar to the functionality included in UPF 118 described previously, and the SMF functionality of the SMF+PGW-U 308 and 408 may be substantially similar to the functionality included in the SMF 114 described previously, and may each be implemented, separately or combined, by a combination of hardware processing circuitry and software and/or firmware comprising machine-readable instructions that are executable by the hardware processing circuitry, or software comprising machine-readable instructions that are executable by a hardware processing circuitry of an apparatus.
[0091] The issue with providing ATSSS functionality in a communication network when one access of the communication network is connected to a 5GC and the other access of the communication network is connected to an EPC, as in the example communication networks 300 and 400 shown in FIGS. 3 and 4, is that the current PFCP model described previously with reference to FIG. 2 does not support such MA-PDU sessions in such communication networks.
[0092] The GTP-U session container header (including the QFI) that is inserted by the UPF in the DL data packets in accordance with the convention PFCP protocol will result in an error when the DL data packet is transmitted on the EPC access path. This is because the information contained in this header, e.g., any of the QFI, RQI, or PPI, is 5G-specific information that will not be comprehended by the 4G endpoint receivers in the EPC access path, such as, for example, the E-UTRAN 314 of the example communication network 300 and the ePDG 414 of the example communication network 400 described previously.
[0093] This error does not arise in PDU sessions that do not use ATSSS because the DL traffic is not split between a EPC access paths and a 5GC access path. Accordingly, when ATSSS is not used, the SMF+PGW-C can, for example, set (or not) the QFI information element (IE) in the QER described previously associated with the PDR for the PDU session to ensure that such 5GC-specific information is always inserted if the 5GC access path is being used for the PDU session or never inserted if the EPC access path is used for the PDU session..
[0094] This error exists only for DL traffic associated with a MAR when ATSSS is used to split the traffic between two accesses pertaining to EPC and 5GC.
[0095] In addition to the issues created by including the QFI in DL packets being sent to an access connected to an EPC, the same problem applies to other 5GC-specific information included in other IEs of the QER that may be inserted in the GTP-U PDU session container header, such as: Reflective QoS This IE shall be present if the UP function is required to insert a Reflective QoS Indicator to request reflective QoS for uplink traffic. RQI Paging Policy Indicator This IF shall be present if the UPF is required to set the Paging Policy Indicator (PPI) in outgoing packets (see clause 5.4.3.2 of 3GPP TS 23.501 [28]). Paging Policy Indicator When present, it shall be set to the PPI value to set.
[0096] Under the conventional PFCP model, the SMF can only instruct the UPF to insert the GTP-U PDU Session Container header, which contains the QFI and may contain the RQI and PPI, for all DL traffic of a PDU session. The conventional PFCP model does not support including the 5GC-specific information into the header of a PDU container session only for DL traffic to be sent along the 5GC access path and not including such 5GC-specific information for DL traffic to be sent along the EPC access path.
[0097] Embodiments of the present disclosure address the problem of providing MA-PDU connectivity services when one access of a UE is connected to an EPC and the other access is connected to a 5GC, such as the example communication networks 300 and 400 described previously with reference to FIGS. 3 and 4 by causing the UPF to include the 5GC-specific information, such as the GTP-U PDU session container header, only in PDU session containers including DL data packets that are transmitted along the 5GC access path, and sending DL packets in a PDU session container along the EPC access path that does not include such 5GC-specific information in, for example, a PDU session container header of the PDU session container.
[0098] FIG. 5 is a flowchart showing an example method or process for providing DL data packets to a UE in a MA-PDU session in which one access is connected to a 5GC in a 5GC access path and the other access is connected to an EPC in an EPC access path. The method or process is performed by a UPF of the network, such as the example UPF+PGW-U 310 or 410 of the example communication networks 300 and 400 described previously with reference to FIGS. 3 and 4.
[0099] At 502, packet detection rules (PDRs) are received at a UPF from an SMF. The received PDRs are associated with a packeting forwarding control protocol (PFCP) session established by the SMF as described previously. The PDRs may be associated with MARS, FARS, QERs, and URRs. As described in more detail below, in some embodiments some or all of the MARs, FARs, or QERs may differ from conventional MARs, FARs, and QERs.
[00100] The PFCP session is associated with a MA-PDU session in which a first access is connected to the UPF via a 5GC in a 5GC access path, and a second 10 access is connected to the UPF via an EPC in an EPC access path.
[00101] At 504, a data packet associated with the PFCP session is received at the UPF from a data network. The UPF may determine that the DL packet is associated with the PFCP session as described previously in order to determine which PDR is to be applied to the DL packet.
[00102] At 506, a determination is made which of the EPC access path or the 5GC access path the data packet is to be sent on. The determination at 506 may be performed based on the PDR associated with the PFCP session that matches the data packet and based on the other rules associated with this DL PDR.
[00103] For example, the determination at 506 may be performed based on information included in the FAR(s) of the 3GPP access and non-3GPP access information of the MAR associated with the PDR. In some embodiments, the information may be included in the forwarding parameters IEs of the FAR.
[00104] In one embodiment, a new "System Type" information element, which may alternatively be named "Core Network Type", may be included in the forwarding parameters IE of the FAR that enables the UPF to distinguish between, for example, EPC and 5GC, or between any two network system types, and may be used at 506 to determine which access path to utilize to transmit the data packet.
[00105] The below table shows an example of a Forwarding Parameters IE in FAR that includes the new System Type IE, shown bolded and underlined for emphasis: Octet 1 and 2 Forwarding Parameters E Type = 4 (decimal) Octets 3 and 4 Length =11 Information elements P Condition I Comment Appl IE Type Sx a Sx b Sx c N4 N4 mb Destination Interface M This IE shall identify the destination interface of the outgoing packet. X X X X - Destination Interface Network Instance 0 VVhen present, this IE shall identify the Network instance towards which to send the outgoing packet. See NOTE 1. X X X X - Network Instance Redirect Information c This IE shall be present if the UP function is required to enforce traffic redirection towards a redirect destination provided by the CP function. - X X)( - Redirect Information Outer Header Creation C This IE shall be present if the UP function is required to add one or more outer header(s) to the outgoing packet. If present, it shall contain the F-TEID of the remote GTP-U peer when adding a GTP-U/UDP/IP header, or the Destination IP address and/or Port Number when adding a UDP/IP header or an IP header or the C-TAG/S-TAG (for 5GC). See NOTE 2. X X - X - Outer Header Creation Transport Level Marking c This IE shall be present if the UP function is required to mark the IP header with the DSCP marking as defined by IETF RFC 2474 [22]. When present for EPC, it shall contain the value of the DSCP in the TCS/Traffic Class field set based on the QCI, and optionally the ARP priority level, of the associated EPS bearer, as described in clause 5.10 of 3GPP TS 23.214 [2]. When present for 5GC, it shall contain the value of the DSCP in the TOS/Traffic Class field set based on the 5QI, the Priority Level (if explicitly signalled), and optionally the ARP priority level, of the associated QoS flow, as described in clause 5.8.2.7 of 3GPP TS 23.501 [28], X X - X - Transport Level Marking Forwarding Policy c This IE shall be present if a specific forwarding policy is - X X X - Forwarding required to be applied to the packets It shall be present if Policy the Destination Interface IE is set to SGi-LAN / N6-LAN. It may be present if the Destination Interface is set to Core, Access, or CP-Function. See NOTE 2.
VVhen present, it shall contain an Identifier of the Forwarding Policy locally configured in the UP function.
Metadata 0 This IE may be included to provide the metadata by the AF which the UPF needs to add to traffic sent over a Service Function Chain. - - - X - Metadata How the UPF transforms the metadata into actual information sent with the traffic (e.g., in the encapsulation header) is based on local policies related vvith the Forwarding Policy and not specified.
Header Enrichment 0 This IE may be present if the UP function indicated support of Header Enrichment of UL traffic. When present, it shall contain information for header enrichment. - X X X - Header Enrichment octet 1 and2 '_ Forwarding Para meters IE Type -, 4 (decimal) Octets 3 and Length = n Information elements P Condition I Comment Appl IE Type Sx a Sx b Sx c N4 N4 mb Linked Traffic Endpoint ID C This IE may be present, if it is available and the UP function indicated support of the PDI optimisation feature, (see clause 8.2.25). When present, it shall identify the Traffic Endpoint ID allocated for this PFCP session to receive the traffic in the reverse direction (see clause 5.2.3.1). X X X Traffic Endpoint ID Proxying C This IE shall be present if proxying is to be performed by the UP function. X Proxying When present, this IE shall contain the information that the UPF shall respond to Address Resolution Protocol and / or IPv6 Neighbour Solicitation based on the local cache information for the Ethernet PDUs.
Destination Interface Type 0 This IE may be present to indicate the 3GPP interface type of the destination interface, if required by functionalities in the UP Function, e.g. for performance measurements. X X X 3GPP Interface Type Data Network Access Identifier C This IE shall be present over N16a to link the UL FAR in an UL CL or BP towards a specific local PSA, if more than one local PSA has been inserted by an I-SMF. It may be present over N16a otherwise. This IE shall not be sent over N4. Data Network When present, it shall be set to the DNAI associated to the local PSA towards which the UL traffic shall be forwarded. Access Identifier IP Address and Port Number Replacement C This IE shall be present if the UP function indicated support of replacing the source and destination IP address and Port Number of an (inner) IP packet, and if the source or destination IP address and/or port number of the (Inner) IP packet shall be modified, e.g. for Edge Relocation using EAS IP address and Port number Replacement (see clause 5.33.3). X IP Address and This IE shall also be present if the destination IP address and/or port number of the (Inner) IP packet shall be modified, e.g. for EAS Discovery procedure with Local DNS Server/Resolver using Local DNS Server/Resolver IP address and Port number Replacement (see clause 5.33.4). Port Number (NOTE 3) Replacement System 0 This IE may be present and set to "EPC" or "5GC" X System Type Type (e.g. when the FAR is referenced by a MAR for ATSSS L Core between an access connected to EPC and an access connected to 5GC). When present, it shall indicate or Core Network whether the outgoing tunnel corresponds to an Network Type) -Noel access through EPC or through 5GC.
[00106] In another example, the "system type" information element may be included in per-access forwarding action information provided to the UPF in, for example, the MAR of the PFCP session associated with the data packet. The below table shows an example of attributes with the MAR that include the new System Type information element in the per-access forwarding action information, shown bolded and underlined for emphasis:
Attribute Description Comment
N4 Session ID Identifies the N4 session associated to this MAR.
Rule ID Unique identifier to identify this rule.
Steering functionality (NOTE 5) Indicates the applicable traffic steering functionality: Values "MPTCP functionality", "ATSSS-LL functionality", "MPQUIC functionality".
Transport Mode Identifies the transport mode (see The Transport Mode shall be included only when the Steering Functionality is the MPQUIC functionality. In all other cases, the Transport Mode shall not be included.
clause 5.32.6.2.2.1) that should be used for the matching traffic, when the Steering functionality is the MPQUIC functionality.
Steering mode (NOTE 5) Values "Active-Standby", "Smallest Delay", "Load Balancing", or "Priority-based" or "Redundant'.
Steering Mode Indicator (NOTE 4) Indicates either autonomous load-balance operation or UE-assistance operation if steering mode is set to "Load Balancing".
Threshold values (NOTE 3, NOTE 4) A Maximum RTT and/or a Maximum Packet Loss Rate The Threshold Values are applied by UPF as described in clause 5.32.8.
Per-Access Forwarding Action information (NOTE 1) (NOTE 2) Forwarding Action Rule ID The Forwarding Action Rule ID identifies a forwarding action that has to be applied.
Weight Identifies the weight for the FAR if steering mode is "Load Balancing" The weights for all FARs need to sum up to 100 Priority Values "Active or Standby" or "High or Low" for the FAR "Active or Standby" for "Active-Standby" steering mode and "High or Low" for "Priority-based" steering mode List of Usage Reporting Rule ID(s) Every Usage Reporting Rule ID identifies a measurement action that has to be applied. This enables the SMF to request separate usage reports for different FARs (i.e. different accesses) System Type This IE may be present and set to "EPC" or This enables the UPF to or "5GC" for a MAR for ATSSS between an insert the DR only for DL Network access connected to EPC and an access traffic sent on 5GC access.
Typel connected to 5GC. When present, it shall indicate whether the corresponding access is through EPC or 5GC.
[00107] In another embodiment, the determination at 506 may be performed based on the "Destination Interface Type" information element conventionally included in the forwarding parameters IE of the FAR (defined as 3GPP Interface Type identifying the name of a specific 3GPP interface), and is included in the example table above.
[00108] If the determination at 506 is that the data packet is to be sent on the 5GC access path ("5GC Access Path" in FIG. 5), then the process moves to 508 and the UPF inserts 5GC-specific information into a header of the data packet and transmits the data packet, with the 5GC-specific information, along the 5GC access path. This process of inserting the 5GC-specific information into a header of the data packet may be performed by inserting the 5GC-specific information into a PDU session container header of a PDU session container that includes the data packet as payload, and transmitting the data packet, with the 5GC-specific information be performed by transmitting the PDU session container that includes the data packet as payload and includes in the 5GC-specific information in the PDU session container header.
[00109] If the determination at 506 is that the data packet is to be sent on the EPC access path ("EPS Access Path" in FIG. 5), then the process moves to 510 and the UPF transmits the data packet along the EPC access path, wherein the data packet transmitted on the EPC access path does not include the 5GCspecific information in a header associated with the data packet such as, for example, a PDU session container header of a PDU session container that includes the data packet.
[00110] The 5GC-specific information may be any information that the UPF is instructed to include in the header of a downlink data packet in accordance with the current 3GPP specification for 5G, but that would result in an error if such information were included in a data packet transmitted to a UE via an EPC. As described previously, the 5GC-specific information may include any of an QFI, an RQI, or an PPI inserted in a GTP-U PDU session container header, or may include the GTP-U PDU session container header generally, or any 5G specific GTP-U extension header more generally.
[00111] In general, the method illustrated in the flowchart in FIG. 5 results in 5GC-specific information, such as, for example, a QFI, a PPI, and/or a RQI, being inserted into a header associated with a DL data packet, such as a PDU session container header of a PDU session container that includes the DL data packet, based on satisfying the condition that the DL data packet is to be transmitted via the 5GC only, i.e., on the 5GC access path, and not transmitted via an EPC, i.e., on the EPC access path. The conditional insertion of the 5GC-specific information results in the PDU session containers that include the 5GC-specific information being transmitted only via the 5GC, and not via an EPC, to avoid the errors that would result from endpoints associated with an EPC access path receiving data traffic that includes 5GC-specific information, as described previously.
[00112] The manner in which 5GC-specific information is included in headers associated with data packets to be transmitted on the 5GC access path and is not included in headers associated with data packets to be transmitted on the EPC access path may be performed in any suitable manner.
[00113] In one embodiment, the PDRs for the PFCP session associated with a MA-PDU session in which one access is connected to a 5GC and the other access is connected to an EPC may be substantially similar to the PDRs for a PFCP session of a MA-PDU session in which both accesses are connected to the 5GC, such as the communication network 100 described previously with reference to FIG. 1.
[00114] In this example, no changes to the conventional MARs or QERs (defined in the current 3GPP specification for 5G) are made in order to effect the conditional insertion of 5GC-specific information into a header of the DL data packet, and the UPF may be pre-configured to perform the method illustrated by the flow chart shown in FIG. 5.
[00115] In this example, the UPF may be configured to determine at 506 which access path, 5GC or EPC, the DL data packet is to be sent on, insert 5GC-specific information into the header associated with the DL data packet, such as a PDU session container header of a PDU session container that includes the DL data packet, to be sent on the 5GC access path at 508 when the UPF determines at 506 that the 5GC access path is to be used, and not insert the 5GC-specific information into the header associated with the DL data packet when the DL data packet is to be sent on the EPC access path at 510 when the UPF determines at 506 that the EPC access path is to be used.
[00116] In another embodiment, the UPF is instructed to conditionally insert 5GC-specific information into a header associated with a DL data packet, such as a PDU session container header of a PDU session container that includes the DL data packet, based on specific rules or IEs inserted into the PDRs or other rules associated with the PDRs that are received by the UPF and applied to the DL data packet.
[00117] For example, the QERs included in the PDRs of the PFCP session associated with the data packet may be extended relative to the conventional QERs described previously to support conditional marking of 5GC-specific information, such as, for example, one or more of a QFI, a PPI, or a RQI, being conditionally inserted into a header associated with a DL data packet when the condition that the DL data packet is to be sent on a 5GC access path is satisfied. The header may be, for example, a GTP-U PDU session container header of a GTP-U session container that includes the DL data packet.
[00118] In this example, the determination of whether the condition is satisfied, i.e., that data packet is to be sent on the access connected to the 5GC, may be made as described previously with reference to 506 of FIG. 5. When the condition is not satisfied, i.e., the data packet is to be transmitted along the EPC access path, the information element in the conventional QERs instructing the UPF to insert the 5GC-specific information in a header of the data packet, such as a PDU session container header of a PDU session container that includes the DL data packet, is not applied, and the data packet is sent on the EPC access path without the 5GC-specific information included in a header associated with the DL data packet.
[00119] In a first example of this embodiment, the QERs include an additional rule, or IE, or "attribute", for "Conditional QFI marking" not present in conventional QERs. This conditional QFI attribute applies only when one access is connected to an EPC and the other access is connected to a 5GC, and instructs the UPF to insert the QFI value only in headers associated with DL data packets that are to be transmitted to an access connected to 5GC and not connected to EPC, i.e., the 5GC access path, and instructs the UPF not to insert the QFI value in headers associated with DL data packets that are to be transmitted on an access connected to an EPC, i.e., the EPC access path.
[00120] An example of such QER is shown below, in which the addition rule not included in conventional QER is shown bolded and underlined:
Attribute Description Comment
N4 Session ID Identifies the N4 session associated to this QER Rule ID Unique identifier to identify this information.
QoS Enforcement Rule correlation ID (NOTE 1) An identity allowing the UP function to correlate multiple Sessions for the same UE and APN. Is used to correlate QoS Enforcement Rules for APNAMBR enforcement.
Gate status UL/DL Instructs the UP function to let the flow pass or to block the flow. Values are: open, close, close after measurement report (for termination action "discard").
Maximum bitrate The uplink/downlink maximum bitrate to be enforced for the packets. This field may e.g. contain any one of: - APN-AMBR (for a QER that is referenced by all relevant Packet Detection Rules of all PDN Connections to an APN) (NOTE 1).
- Session-AMBR (for a QER that is referenced by all relevant Packet Detection Rules of the PDU Session) - QoS Flow MBR (for a QER that is referenced by all Packet Detection Rules of a QoS Flow) - SDF MBR (for a QER that is referenced by the uplink/downlink Packet Detection Rule of a SDF) - Bearer MBR (for a QER that is referenced by all relevant Packet Detection Rules of a bearer) (NOTE 1).
Guaranteed bitrate The uplink/downlink guaranteed bitrate authorized for the packets. This field contains: - QoS Flow GBR (for a QER that is referenced by all
Attribute Description Comment
Packet Detection Rules of a QoS Flow) - Bearer GBR (for a QER that is referenced by all relevant Packet Detection Rules of a bearer) (NOTE 1).
Averaging window The time duration over which the Maximum and Guaranteed bitrate shall be calculated. This is for counting the packets received during the time duration.
Down-link flow level marking Flow level packet marking in the downlink. For UPF, this is for controlling the setting of the RQI in the encapsulation header as described in clause 5.7.5.3.
QoS Flow ID QoS Flow ID to be inserted by the UPF. The UPF inserts the QFI value in the tunnel header of outgoing packets. If Conditional QFI marking applies, the UPF does so only if the condition expressed to insert the QFI is satisfied.
Conditional OFI This IE shall be present for an N4 Session The UPF inserts the QFI value marking related with ATSSS between an access in the tunnel header of connected to EPC and an access connected outgoing packets only if they to 5GC. This may be present otherwise. are sent on an access When present, this instructs the UPF to connected to 5GC.
insert the OFI value only for an access connected to 5GC".
Paging Policy Indicator Indicates the PPI value the UPF is required to insert in outgoing packets (see clause 5.4.3.2). PPI applies only for DL traffic.
The UPF inserts the PPI in the outer header of outgoing PDU.
Packet rate (NOTE 1) Number of packets per time interval to be enforced. This field contains any one of: - downlink packet rate for Serving PLMN Rate Control (the QER is referenced by all PDRs of the UE belonging to PDN connections using CloT EPS Optimisations as described in TS 23.401 [26]).
- uplink/downlink packet rate for APN Rate Control (the QER is referenced by all PDRs of the UE belonging to PDN connections to the same APN using CloT EPS Optimisations as described in TS 23.401 [26]).
End of Data Burst Marking Indication Indicates to the UPF to provide an End of Data Burst indication of the last PDU of a Data burst to the NG-RAN over GTP-U NG-RAN can configure UE power management schemes like connected mode DRX when UPF provides an indication of the End of Data Burst, see clause 5.37.8.3 PDU Set Information marking Indicator Indicates the UPF to insert PDU Set Information related to packets belonging to a PDU Set into GTP-U header. UPF identifies PDU Sets in DL traffic and forwards PDU Set related information of each PDU to the NG-RAN over GTP-U, as described in clause 5.37.5.
Attribute Description Comment
NOTE 1: This parameter is only used for interworking with EPC [00121] In another example, the QER may include a new attribute QFI marking flag that is set when one access is connected to an EPC and the other access is connected only to a 5GC. In this example, the flag, when set, instructs the UPF to insert the QFI value only in headers associated with DL data packets that are to be sent on an access connected to the 5GC, i.e., the 5GC access path, which may be determined as described previously with reference to 506 of FIG. 5.
[00122] An example of such QER is shown below, in which an additional new attribute, "QFI marking for 5GC access only" flag, not included in conventional QERs is shown bolded and underlined:
Attribute Description Comment
N4 Session ID Identifies the N4 session associated to this QER Rule ID Unique identifier to identify this information.
QoS Enforcement Rule correlation ID (NOTE 1) An identity allowing the UP function to correlate multiple Sessions for the same UE and APN. Is used to correlate QoS Enforcement Rules for APNAMBR enforcement.
Gate status UL/DL Instructs the UP function to let the flow pass or to block the flow. Values are: open, close, close after measurement report (for termination action "discard").
Maximum bitrate The uplink/downlink maximum bitrate to be enforced for the packets. This field may e.g. contain any one of: - APN-AMBR (for a QER that is referenced by all relevant Packet Detection Rules of all PDN Connections to an APN) (NOTE 1).
- Session-AMBR (for a QER that is referenced by all relevant Packet Detection Rules of the PDU Session) - QoS Flow MBR (for a QER that is referenced by all Packet Detection Rules of a QoS Flow) - SDF MBR (for a QER that is referenced by the uplink/downlink Packet Detection Rule of a SDF) - Bearer MBR (for a QER that is referenced by all relevant Packet Detection Rules of a bearer) (NOTE 1).
Guaranteed bitrate The uplink/downlink guaranteed bitrate authorized for the packets. This field contains: - QoS Flow GBR (for a QER that is referenced by all
Attribute Description Comment
Packet Detection Rules of a QoS Flow) - Bearer GBR (for a QER that is referenced by all relevant Packet Detection Rules of a bearer) (NOTE 1).
Averaging window The time duration over which the Maximum and Guaranteed bitrate shall be calculated. This is for counting the packets received during the time duration.
Down-link flow level marking Flow level packet marking in the downlink. For UPF, this is for controlling the setting of the RQI in the encapsulation header as described in clause 5.7.5.3.
QoS Flow ID QoS Flow ID to be inserted by the UPF. The UPF inserts the QFI value in the tunnel header of outgoing packets. If Conditional QFI marking applies, the UPF does so only if the condition expressed to insert the QFI is satisfied.
"QFI marking for 5GC This IE shall be set to 1 for an N4 Session When set to 1. this instructs access on h. flag related with ATSSS between an access the UPF to insert the QFI value connected to EPC and an access connected only for an access connected to 5GC. This may be present otherwise. to 5GC.
Paging Policy Indicator Indicates the PPI value the UPF is required to insert in outgoing packets (see clause 5.4.3.2). PPI applies only for DL traffic.
The UPF inserts the PPI in the outer header of outgoing PDU.
Packet rate (NOTE 1) Number of packets per time interval to be enforced. This field contains any one of: - downlink packet rate for Serving PLMN Rate Control (the QER is referenced by all PDRs of the UE belonging to PDN connections using CloT EPS Optimisations as described in TS 23.401 [26]).
- uplink/downlink packet rate for APN Rate Control (the QER is referenced by all PDRs of the UE belonging to PDN connections to the same APN using CloT EPS Optimisations as described in TS 23.401 [26]).
End of Data Burst Marking Indication Indicates to the UPF to provide an End of Data Burst indication of the last PDU of a Data burst to the NG-RAN over GTP-U NG-RAN can configure UE power management schemes like connected mode DRX when UPF provides an indication of the End of Data Burst, see clause 5.37.8.3 PDU Set Information marking Indicator Indicates the UPF to insert PDU Set Information related to packets belonging to a PDU Set into GTP-U header UPF identifies PDU Sets in DL traffic and forwards PDU Set related information of each PDU to the NG-RAN over GTP-U, as described in clause 5 37 5 NOTE 1: This parameter is only used for interworking with EPC.
[00123] Although the above QERs examples include an attribute related to conditional marking for the QFI only, in practice this modification could encompass attributes instructing the UPF to perform such condition marking related to any 5GC-specific information in addition to, or alternative to, conditional QFI marking such as, for example, conditional PPI and/or RQI marking as well, or conditional insertion of the GTP-U session container header generally in a container that includes the DL data packet as payload, as described previously.
[00124] In yet another example, the MAR received from the SMF includes access specific QER ID(s), i.e. enabling the MAR to associated each access, i.e., each of the 3GPP and non-3GPP accesses, with access specific QERs, i.e. QER(s) specific to the 3GPP access and another QER(s) specific to the non-3GPP access of a MAR, where the QERs of an access connected to the 5GC requires the inclusion of 5GC-specific information such as QFI, i.e. for DL data packets to be transmitted on the 5GC access path, and where no QER or QER(s) not requiring the inclusion of 5GC-specific information are applied for the access connected to the EPC, i.e. for DL data packets to be transmitted on the EPC access path.
[00125] In this example, one set of QERs are applied to data packets to be sent along the 5GC access path, which instruct the UPF to insert the 5GC-specific information in a header associated with the data packet, such as a PDU session container header of a PDU session container that includes the data packet, and another set of QERs (or no QER) are applied to data packets to be sent along the EPC access path, which do not instruct the UPF to insert the 5GC-specific information in a header associated with the data packet, such as a PDU session container header of a PDU session container that includes the data packet. The SMF may set a QER identifier (QER ID) for each of the separate sets of QER, and the MAR instructs the UPF, using the QER ID, which set of QER to apply to a data packet based on which of the 5GC/EPC access paths is to be used to transmit the data packet, which may be determined as described previously at 506 of FIG. 5.
[00126] In some examples, the PDR5 of the PFCP session may include a third set of common QERs that are applied to all data packets associated with the PFCP session regardless of which of the 5GC/EPC access paths they are to be sent on. These common QERs may include, for example, QER IEs that are not related to including the 5GC-specific information in a header associated with the data packet.
[00127] Referring to FIG. 6, and schematic diagram illustrating how a UPF 600 may determine which QERs to use is shown based on a PFCP model that includes access specific QERs. The example UPF 600 may include UPF functionality similar to any of the UPF functionality included in the UPFs previously described such as, for example, the UPF functionality included in UPF+PGW-U 310 and 410 of the example networks 300 and 400 previously described with reference to FIGS. 3 and 4.
[00128] A data packet is received at the UPF 600, and a PDR 602 associated with a PFCP session for the data packet is determined. The PDR may be received at the UPF 600 from an SMF (not shown) that establishes or modifies the PFCP session. This determination may be performed similar to the determination described previously with reference to FIG. 2 and is not further described here. The PDR 602 has a MAR 604 for the PFCP session.
[00129] The MAR 604 causes the UPF 600, when the access path to be used for transmitting the data packet is determined to be the 5GC access path, to apply a first QER 1 606 to the data packet, in addition to the FAR 1 608 that are applied to that access, i.e., 3GPP or non-3GPP. The QER 1 606 instructs the UPF 600 to include 5GC-specific information in a header associated with the data packet, such as a PDU session container header of a PDU session container that includes the data packet, prior to transmitting the data packet, i.e., the PDU session container that includes the data packet, out along the 5GC access path.
[00130] The MAR 604 causes the UPF 600, when the access path to be used for transmitting the data packet is determined to be the EPC access path, to apply a second QER 2 610 is applied to the data packet, in addition to the FAR 2 612 that are applied to that access, i.e., non-3GPP or 3GPP. The QER 2 610 does not include instructions for the UPF 600 to insert 5GC-specific information into a header associated with the data packet prior to sending the data packet out along the EPC access path. In other examples, no QER 2 610 may be included, and the MAR 604 causes the UPF 600 not to apply any specific QER to the DL data packet that is to be transmitted on the EPC access path.
[00131] As described previously, the PDR 602 may optionally include common QER 3 614 that are applied by the UPF 600 to the data packet regardless of which access path that data packet is to be transmitted on.
[00132] In order to establish the PFCP session as described above and illustrated in FIG. 6, the existing forward action information for the outgoing tunnels associated with the 3GPP access and the non-3GPP access, which enable creation of separate FARs for each outgoing tunnel, may be utilized. A new QER ID information element may be included in the forward action information for the outgoing tunnel associated with each of the 3GPP and non-3GPP accesses.
[00133] The forwarding action information for each of the 3GPP and non-3GPP access that exists in the Create MAR IE within a PFCP session establishment request are shown below, bolded for reference: Octet I and 2 Create MAR IE Type= 165 IdepirnalI Octets 3 and 4 Length:= it Information P Condition! Comment Apo!. IE Type elements Sxa Sxb Sxc N4 N4mb MAR ID M This IE shall uniquely identify the MAR among all the MARs configured for that PFCP session. X MAR ID Steering Functionality M This IE shall be present to indicate the applicable traffic steering functionality. X Steering Functionality Steering Mode M This IE shall be present to indicate the steering mode. X Steering Mode 3GPP Access Forwarding Action Information C This IE shall be present to provision 3GPP access specific forwarding action information if the UE is registered for 3GPP access, except when steering mode is set to "Active-Standby", Non-3GPP access is the active access and 3GPP access is not used as Standby access. In the latter case, this IE may be present. X 3GPP Access (NOTE) Forwarding Action Information Octet I end 2 Create MAR IE Type:: 185 (decimal) Octets 3 and 4 Length = n Information elements P Condition / Comment Appi. IE Type Sxa Sxb Sxc N4 N4mb Non-3GPP Access Forwarding Action C This IE shall be present to provision non-3GPP access specific forwarding action information if the UE is registered for non-3GPP access, except when steering mode is set to "Active-Standby", 3GPP access is the active access and Non-3GPP access is not used as Standby access. In the latter case, this IE may be present. X Non-3GPP Information (NOTE 1) Access Forwarding Action Information Threshold Values C This IE shall be present if the steering mode is "Load Balancing" with fixed split percentages or "Priority-based" and if available. This IE may also be present if the steering mode is "Redundant". X Thresholds When present, this IE shall contain the RTT and/or a Packet Loss Rate. If the Steering Mode is Redundant, either a (maximum) RTT or a (maximum) Packet Loss Rate may be provided, but not both.
(NOTE 2) Steering Mode Indicator C This IE shall be included if at least one of the flags is set to "1": X Steering Mode - ALBI (Autonomous Load Balancing Indicator): Indicator this flag shall be set to "1" if the SMF allows the UPF to apply autonomous load-balance when the Steering Mode is Load-Balancing; - UEAI (UE Assistance Indicator): this flag shall be set to "1" if the SMF allows UE assistant load-balance when the Steering Mode is Load-Balancing.
(NOTE 2) Transport Mode C This IE shall be present to indicate the transport mode of the MPQUIC functionality, if the Steering Functionality is set to the MPQUIC functionality. In all other cases, this IE shall be absent. X Transport Mode NOTE 1: For the 'Active-Standby" steering mode, if the network determines to not define a S andby access (as specified in clause 5.32.8 of 3GPP TS 23.501 [28]), the SMF shall either set the Priority IE wi hin Non-)3GPP Access Forwarding Action Information IE to the value "No Standby" or not include the (Non)3GPP Access Forwarding Action Information IE for that access not defined as Standby access.
NOTE 2: The Threshold Values IE and the Steering Mode Indicator IE shall not be present together.
[00134] The forwarding action information in the create MAR IE for both the 3GPP access and the non-3GPP access includes a QER ID which uniquely identifies the QER to be used among all of the QERs configured for the PFCP session, and enables the SMF to establish separate QoS related instructions for different FARs such that the QERs that are applied to DL data packets transmitted on the 5GC access path have the 5GC-specific information inserted into a header associated with the DL data packets. Examples of the Access Forwarding Action Information IE in the Create MAR IE for 3GPP and non-3PGG are included below, with the new "QED ID" information element shown in bolding and under ining for emphasis: Octet 1 and 2 3GPP Access Foiwarding Acton Information I FE Type = 166 (decimal) Octets a and 4 _ Length '= n Information P Condition! Comment Appl. IE Type elements Sxa Sxb Sxc N4 N4mb FAR ID M This IE shall uniquely identify the FAR among all the FARs configured for this PFCP session. X FAR ID Weight C This IE shall be present if steering mode is set to "Load Balancing" to identify the weight of the FAR. (NOTE 1) X Weight Priority C This IE shall be present if the steering mode is set to "Active-Standby" or "Priority-based". This IE may be present if the steering mode is set to "Redundant". (NOTE 2) X Priority URR ID C This IE shall uniquely identify the URR among all the URRs configured for the PFCP session. This enables the SMF to request separate usage reports for different FARs (i.e. different accesses) (NOTE 3) X URR ID Several IEs within the same IE type may be present to represent a list of URRs to be associated to the FAR.
QER ID C This IE shall uniquely identify the QER among all - - - X z QER ID
_ _ _
the QERs configured for the PFCP session. This enables the SMF to request separate QoS related instructions for different FARs (i.e. different accesses), e.g. to request the inclusion of QFI, PPI or RQI only for the 5GC access for a MA PDU session with a 5GC access and an EPC access.
RAT Type 0 This IE may be present to provide the UP Function the current RAT Type for the DL FAR for statistics purpose. X RAT Type NOTE 1: The weights for all FARs included in both 3GPP Access Forwarding Action Informat on and Non 3GPP Access Forwardng Action Information need to sum up to 100. If the autonomous load balance operation is allowed, the Weights shall be treated as the default percentages.
NOTE 2: The Priority value shall be set to "Active", "Standby" or "No Standby" if the Steering Mode is set to "Active-Standby". The Priority value shall be set to "High" or "Love if the Steering Mode is set to "Priority-based". The Priority value shall be set to "Primary" or "Secondary" if the Steering Mode is set to "Redundant" and if the Priority IE is present. The 3GPP Access Forwarding Action Information and Non 3GPP Access Forwarding Action Information shall set different values; for the Redundant Steering Mode, this requirement shall apply only if the Priority IE is present.
NOTE 3: One or more URRs may still be provisioned in the Create PDR IE when an MAR ID is present, while the URR(s) provisioned in this IE shall present a different set of URR(s) to request separate usage reports.
Non-3GPP Access Forwarding Action Information IE Type =:167 decimal) Octets 3 and 4 Information P Condition! Comment Appl. IE Type elements Sxa Sxb Sxc N4 N4mb FAR ID M This IE shall uniquely identify the FAR among all the FARs configured for this PFCP session. X FAR ID Weight C This IE shall be present if steering mode is set to "Load Balancing" to identify the weight of the FAR X Weight Ivl©n-3GPP Access Forwarding Action information IE Type-167 (decimal Octets 3 and 4 Length --7- n Information P Condition / Comment Appl. IE Type elements Sxa Sxb Sxc N4 N4mb (NOTE 1) Priority C This IE shall be present if the steering mode is set to "Active-Standby" or "Priority-based". This IE may be present if the steering mode is set to "Redundant". (NOTE 2) X Priority URR ID C This IE shall uniquely identify the URR among all the URRs configured for the PFCP session. This enables the SMF to request separate usage reports for different FARs (i.e. different accesses) (NOTE 3) X URR ID Several IEs within the same IE type may be present to represent a list of URRs to be associated to the FAR.
QER ID C This IE shall uniquely identify the QER among all - - - X _ QER ID
_ _ _ _
the QERs configured for the PFCP session. This enables the SMF to request separate QoS related instructions for different FARs (i.e. different accesses) e a to request the inclusion of QFI, PPI or RQI only for the 5GC access for a MA PDU session with a 5GC access and an EPC access.
RAT Type 0 This IE may be present to provide the UP Function the current RAT Type for the DL FAR for statistics purpose. X RAT Type NOTE 1: The weights for all FARs included in both 3GPP Access Forwarding Action Information and Non 3GPP Access Forwardng Action Information need to sum up to 100. If the autonomous load balance operation is allowed, the Weights shall be treated as the default percentages.
NOTE 2: The Priority value shall be set to "Active", "Standby" or "No Standby" if the Steering Mode is set to "Active-Standby". The Priority value shall be set to "High" or "Low" if the Steering Mode is set to ''Priority-based". The Priority value shall be set to "Primary" or "Secondary" if the Steering Mode is set to "Redundant' and if the Priority IE is present. The 3GPP Access Forwarding Action Information and Non 3GPP Access Forwarding Action Information shall set different values; for the Redundant Steering Mode, this requirement shall apply only if the Priority IE is present.
NOTE 3: One or more URRs may still be provisioned in the Create PDR IE when an MAR ID is present, while the URR(s) provisioned in this IE shall present a different set of URR(s) to request separate usage reports.
[00135] In this example, the process used by the SMF to establish or modify a conventional PFCP session with the UPF, as set out in the current 3GPP standard for 5GC, may be used. Only the contents to the QER, FAR, and possibly MAR sent from the SMF to the UPF are changed.
[00136] In addition to using separate QERs for each of the 3GPP and non-3GPP accesses to implement conditional 5GC-specific information being inserted into a header associated with the data packets, separate QERs may be used more generally to support specific QoS enforcement that is different for each of the 3GPP and non-3GPP access. For example, if the maximum bit rate (MBR) that can be supported on one access is much lower than the MBR that can be supported by another access, this can be accounted for in different QERs that are specific to each of the accesses.
[00137] In another embodiment, the UPF may be instructed by the PDR5 received from the SMF to remove any 5GC-specific information that is included in a header associated with data packet, such as a PDU session container header of a PDU session container that includes the data packet, before that data packet is transmitted on an EPC access path, rather than instructing the UPF to conditionally insert the 5GC-specific information only into the headers associated with data packets that are to be transmitted on the 5GC access path, and not into the headers associated with data packets that are to be transmitted on the EPC access path, as in previously-described embodiments.
[00138] This embodiment may be implemented by modifying the FAR associated with the EPC access path to include an information element that causes the UPF to remove 5GC-specific information included in a header associated with DL data packets to be transmitted on the EPC access path.
[00139] For example, the FAR for the outgoing tunnel of the UPF associated with the EPC access path may include an additional indication (e.g., a flag) that indicates that any QFI is to be removed. In another example, the FAR for the outgoing tunnel of the UPF associated with the EPC access path may include a new "outer header removal" information element comprising instructions to the UPF that the QFI is to be removed, as shown in the below example FAR in which the "outer header removal" information element is shown in bolding and underlining for emphasis: Octet 1 and 2 Octets 3 and 4 Length = n Information P Condition I Comment Appl. IE Type elements Sx a Sx b Sx c N4 N4 mb Destination Interface M This IE shall identify the destination interface of the outgoing packet. X X X X Destination Interface Network Instance 0 When present, this IE shall identify the Network instance towards which to send the outgoing packet. See NOTE 1. X X X X Network Instance Redirect Information C This IE shall be present if the UP function is required to enforce traffic redirection towards a redirect destination provided by the CP function. X X X Redirect Information Octet 1 and 2 rorwardi Parameter's IE Type = 4 s1. map Octets 3 and 4 Length? = n Information P Condition / Comment Appl. IE Type elements Sx a Sx b Sx c N4 N4 mb Outer Header Creation C This IE shall be present if the UP function is required to add one or more outer header(s) to the outgoing packet. If present, it shall contain the F-TEID of the remote GTP-U peer when adding a GTP-U/UDP/IP header, or the Destination IP address and/or Port Number when adding a UDP/IP header or an IP header or the C-TAG/S-TAG (for 5GC). See NOTE 2. X X X Outer Header Creation Transport Level Marking C This IE shall be present if the UP function is required to mark the IP header with the DSCP marking as defined by IETF RFC 2474 [22]. When present for EPC, it shall contain the value of the DSCP in the TOS/Traffic Class field set based on the QCI, and optionally the ARP priority level, of the associated EPS bearer, as described in clause 5.10 of 3GPP TS 23.214 [2]. When present for 5GC, it shall contain the value of the DSCP in the TOS/Traffic Class field set based on the 5QI, the Priority Level (if explicitly signalled), and optionally the ARP priority level, of the associated QoS flow, as described in clause 5.8.2.7 of 3GPP TS 23.501 [28], X X X Transport Level Marking Forwarding Policy C This IE shall be present if a specific forwarding policy is required to be applied to the packets. It shall be present if the Destination Interface IE is set to SGi-LAN / N6-LAN. It may be present if the Destination Interface is set to Core, Access, or CP-Function. See NOTE 2. X X X Forwarding When present, it shall contain an Identifier of the Forwarding Policy locally configured in the UP function. Policy Metadata 0 This IE may be included to provide the metadata by the AF which the UPF needs to add to traffic sent over a Service Function Chain. X How the UPF transforms the metadata into actual information sent with the traffic (e.g., in the encapsulation header) is based on local policies related with the Forwarding Policy and not specified. Metadata Header Enrichment 0 This IE may be present if the UP function indicated support of Header Enrichment of UL traffic. When present, it shall contain information for header enrichment. X X X Header Enrichment Linked Traffic Endpoint ID C This IE may be present, if it is available and the UP function indicated support of the PDI optimisation feature, (see clause 8.2.25). When present, it shall identify the Traffic Endpoint ID allocated for this PFCP session to receive the traffic in the reverse direction (see clause 5.2.3.1). X X X Traffic Endpoint ID Proxying C This IE shall be present if proxying is to be performed by the UP function. X Proxying When present, this IE shall contain the information that the UPF shall respond to Address Resolution Protocol and / or I Pv6 Neighbour Solicitation based on the local cache information for the Ethernet PDUs.
Destination Interface Type 0 This IE may be present to indicate the 3GPP interface type of the destination interface, if required by X X X 3GPP Interface Type Octet 1 and 2 Forwarding Parameters IE Type -4 amal) Octets 3 and 4 Length = n Information P Condition / Comment Appl. IE Type elements Sx a Sx b Sx c N4 N4 mb functionalities in the UP Function, e.g. for performance measurements.
Data Network Access Identifier C This IE shall be present over N16a to link the UL FAR in an UL CL or BP towards a specific local PSA, if more than one local PSA has been inserted by an I-SMF. It may be present over N16a otherwise. This IE shall not be sent over N4. Data Network When present, it shall be set to the DNAI associated to the local PSA towards which the UL traffic shall be forwarded. Access Identifier IP Address and Port Number Replacement C This IE shall be present if the UP function indicated support of replacing the source and destination IP address and Port Number of an (inner) IP packet, and if the source or destination IP address and/or port number of the (Inner) IP packet shall be modified, e.g. for Edge Relocation using EAS IP address and Port number Replacement (see clause 5.33.3). X IP Address and This IE shall also be present if the destination IP address and/or port number of the (Inner) IP packet shall be modified, e.g. for EAS Discovery procedure with Local DNS Server/Resolver using Local DNS Server/Resolver IP address and Port number Replacement (see clause 5.33 4) Port Number (NOTE 3) Replacement Outer Header C This IE shall be present for FAR to an EPC tunnel, X X: X X Outer Header Removal that may be used by a MAR for ATSSS between an access connected to EPC and an access connected Removal to 5GC, to request the UPF to remove any QFI from the DL packets.
[00140] Although the example FAR included above includes an information element directed to instructing the UPF to remove the QFI only, in practice the FAR could include information elements instructing the UPF to remove any 5GC-specific information in addition to, or alternative to, the QFI such as, for example, removing PPI or RQI as well, or, more generally, instructing the UPF to remove the GTP-U session container header of a GTP-U session container that includes the DL data packet.
[00141] In this embodiment, the UPF may be instructed, or pre-configured, to insert 5GC-specific information into the headers associated with all data packets, regardless of the access path that the data packet is to be transmitted on, in accordance with conventional QERs, but for those data packets to be transmitted on the EPC access path, the 5GC-specific information is removed from the header by the UPF prior to transmitting the data packet in accordance with, for example, the FAR associated with the EPC access path.
[00142] Referring to FIG. 7, a schematic diagram illustrating various physical 5 and logical components of an exemplary apparatus 700 for a communication network in accordance with an embodiment is shown. Although an example embodiment of the apparatus 700 is shown and discussed below, other embodiments may be used to implement examples disclosed herein, which may include components different from those shown. Although FIG. 7 shows a single instance of each component of the apparatus 700, there may be multiple instances of each component shown.
[00143] The apparatus 700 includes one or more processors 702, such as a central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a dedicated logic circuitry, a graphics processing unit (GPU), a tensor processing unit, a neural processing unit, a dedicated artificial intelligence processing unit, a hardware accelerator, or combinations thereof. The one or more processors 702 may collectively be referred to as a processor 702.
[00144] The apparatus 700 also includes one or more memories 104 (collectively referred to as "memory 704"), which may include a volatile or non-volatile memory (e.g., a flash memory, a random-access memory (RAM), and/or a read-only memory (ROM)). The non-transitory memory 704 may store instructions for execution by the processor 702. In some embodiments, instructions 706 of a UPF and/or a SMF described herein may be stored in the memory 704, and the instructions 706 may be executed by the processor 102 to perform the actions or operations of the methods described herein. The memory 704 may include other instructions for execution by the processor 702, such as instructions of other network functions of a communication network, such as those described above.
[00145] The apparatus 700 may also include one or more network interfaces 708 for connecting to a network, such as a data network, or other apparatuses of the core network or the access networks described herein.
[00146] In some examples, the apparatus 700 may also include one or more electronic storage units (not shown), such as a solid state drive, a hard disk drive, a magnetic disk drive and/or an optical disk drive. In some examples, one or more datasets and/or modules may be provided by an external memory (e.g., an external drive in wired or wireless communication with the computing system 100) or may be provided by a transitory or non-transitory computer-readable medium. Examples of non-transitory computer readable media include a RAM, a ROM, an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a CD-ROM, or other portable memory storage. The storage units and/or external memory may be used in conjunction with memory 704 to implement data storage, retrieval, and caching functions of the apparatus 700.
[00147] The components of the apparatus 700 may communicate with each other via a bus. In some embodiments, the apparatus 700 may be a processing system implementing functionality of the UPF and/or the SMF described herein. In some embodiments, the apparatus 700 may be distributed computing system and may include multiple computing devices in communication with each other over a data network, as well as optionally one or more additional components. The various operations described herein may be performed by different computing devices of a distributed computing system in some embodiments. In some embodiments, the apparatus 700 a cloud computing system or may be a virtual machine provided by a cloud computing system.
[00148] Embodiments of the present invention including functions, processes, and operations, may be implemented in software, hardware, application logic or a combination of software, hardware and application logic. The software, application logic and/or hardware may reside on memory, or any computer media. In an example embodiment, the application logic, software or an instruction set is maintained on any one of various conventional computer-readable media. In the context of this application, a "memory" or "computer-readable medium" may be any non-transitory media or means that contains, stores, communicates, propagates or transports the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.
[00149] Reference to, where relevant, "computer-readable medium", "computer program product", "tangibly embodied computer program" etc., or a "processor" or "processing circuitry" etc. should be understood to encompass not only computers having differing architectures such as single/multi-processor architectures and sequencers/parallel architectures, but also specialized circuits such as field programmable gate arrays FPGA, application specify circuits ASIC, signal processing devices/apparatus and other devices/apparatus. References to computer program, instructions, code etc. should be understood to express software for a programmable processor firmware such as the programmable content of a hardware device/apparatus as instructions for a processor or configured or configuration settings for a fixed function device/apparatus, gate array, programmable logic device/apparatus, etc. [00150] As used in the present disclosure, the term "circuitry", for example in the hardware processing circuitry that may be used to implement the UPF or the SMF in accordance with certain embodiments of the present disclosure, may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (iii) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in the present disclosure, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.
[00151] The functions, processes, and operations described herein may be performed in a different order, or may be performed concurrently with each other, or a combination thereof. Furthermore, one or more of the functions, processes, and operations may be optional or may be combined. It will be appreciated that the flow diagram shown in FIG. 5 and the various embodiments described with reference to FIG. 5, are examples only. Various operations and processes depicted therein may be omitted, may be reordered, may be combined, or a combination of reordered and combined.
[00152] Advantageously, the UPF transmitting data packets on a 5GC access pathway in which 5GC-specific information is inserted into headers associated those data packets and transmitting data packets on an EPC access pathway with no 5GC-specific information included in a header associated with those data packets enables MA-PDU connectivity services when one of a 3GPP access and a non-3GPP access is connected to a 5GC and the other of the 3GPP access and the non-3GPP access is connected to an EPC.
[00153] The scope of the claims should not be limited by the preferred embodiments set forth in the examples but should be given the broadest interpretation consistent with the description as a whole.