DNS traffic routing for ues with same ip address

Abstract

Disclosed herein is at least one method for home routed (HR) session breakout (SBO) of a PDU session of a UE using a private Internet Protocol (IP) address performed by a V-SMF in a PLMN. The method comprises obtaining tunnel information for establishing a tunnel (e.g., HR-SBO of a PDU session of a UE using a private IP address) between a V-UPF and a V-EASDF; and based on the obtained tunnel information, performing one or more operations involving establishing a tunnel (e.g., HR-SBO of a PDU session of a UE using a private IP address) between the V-UPF and the V-EASDF.

Description

Background Technology

[0001] In the 3GPP 5G System (5GS) framework, in Home Routing Session Offloading (HR-SBO) scenarios, there are use cases where User Equipment (UEs) from the same or different Home Public Land Mobile Networks (PLMNs) establish Home Routing Protocol Data Unit (PDU) sessions using the same Private UE Internet Protocol (IP) address. If these UEs are roaming in the same Visited Public Land Mobile Network (VPLMN) supporting HR-SBO and are assigned the same Visited User Plane Function (V-UPF) and the same Visited Edge Application Server Discovery Function (V-EASDF), then if these UEs are assigned the same Private IP address, it will cause problems for V-EASDF in distinguishing these UE / PDU sessions. Therefore, it is impossible to apply control to these HR-SBO PDU sessions. Section 6.7.2.2 of 3GPP Technical Specification (TS) 23.548 (see, for example, V18.4.0) has proposed three candidate solutions, such as establishing a tunnel on N6 between V-UPF and V-EASDF for each PDU session, separating PDU sessions sharing the same UE IP address using different network instances, and assigning a unique N6 IP address to the source IP address of each UE / PDU session. See also the Phase 2 requirements cited below: Based on local configuration, obtain the V-EASDF IP address, or invoke the Neasdf_DNSContext_Create request (including the DNN, S-NSSAI, HPLMN ID, and the UE IP address set to an unspecified address or a mapped address as specified in Section 7.1.2.2) to obtain the V-EASDF IP address; and Note 2: The network needs to ensure that the DF can disambiguate / distinguish DNS services for different UEs that will be assigned the same private UE IP address. This can be achieved by implementing and / or deploying specific means, such as tunneling on N6, network instances, or UE source IP address mapping. To disambiguate / distinguish DNS services for different UEs that are assigned the same private UE IP address, the V-SMF can use the N4 PDR and FAR (including N6 service routing information or network instances) to update the local PSA-UPF (as described in section 5.6.12 of 23.501[2]) to forward DNS services to the V-EASDF. When using an N6 service routing tunnel, the V-SMF can use the N6 service routing information toward the local PSA-UPF to configure the V-EASDF. Alternatively, the V-SMF can update the local UPF to translate the UE source IP address to the alternative IP address in the IP pool of the local PSA UPF.

[0002] Therefore, in the Phase 3 specification, Clause 5.2.3.2.3 of 3GPP TS 29.556 further specifies three candidate implementations to support Domain Name System (DNS) contexts with the same UE IP address from different Single Network Slice Auxiliary Information (S-NSSAI) and Data Network Name (DNN), as follows: The following options can be used to support DNS contexts with the same (private) UE IP address from different S-NSSAI and DNN: - EASDF can associate a specific EASDF address with a specific S-NSSAI and DNN, and provide that address to the SMF during the creation of the DNS context associated with that S-NSSAI and DNN. If so, EASDF should also use the destination IP address of the DNS query message to identify the DNS context that matches the incoming DNS request; - When using UE source IP address mapping at the local PSA-UPF, the SMF can set the UE IP address to the mapped N6 address; When using an N6 tunnel between the L-PSA and V-EASDF, the SMF can provide N6 service routing information (in the DNS context information) for the HR-SBO in the VPLMN. This N6 service routing information may include the IP address and optional port number of the local PSA-UPF. If so, the V-EASDF should also use the N6 service routing information of the DNS query messages to identify the DNS context matching the incoming DNS request.

[0003] Furthermore, in the newly submitted Change Request (CR) #0825 (C4-240329) at the CT4 121 meeting, it was proposed to enable Packet Forwarding Control Protocol (PFCP) sessions in the User Plane Function (UPF) to enable tunneling or IP address replacement, in order to support DNS service routing for different UEs with the same private UE IP address, as follows: In order to support DNS service routing for different UEs with the same private UE IP address for HR-SBO in a VPLMN as specified in Clause 6.7.2.2 of 3GPP TS 23.548

[69] , the SMF shall instruct the UPF: - When using an N6 tunnel between L-PSA UPF and V-EASDF, packets are routed based on the N6 routing information in the FAR (e.g., the V-EASDF's IP address and optional port number are provided in the external header creation); or - When using UE source IP address mapping, the source IP address of the incoming packet is replaced with the replacement IP address from the local PSA UPF IP pool by providing an IP address and port number that includes the replacement IP address to replace the IE's UL FAR. UPFs that support replacing the source IP address of (internal) IP packets should have the IPREP flag set in the UP feature IE (see Section 8.2.25), and should replace the source IP address of (internal) IP packets as instructed by the SMF. Summary of the Invention

[0004] The embodiments described below represent information enabling those skilled in the art to practice these embodiments and illustrate the best mode for practicing these embodiments. Upon reading the following description with reference to the accompanying drawings, those skilled in the art will understand the concepts of this disclosure and recognize the application of these concepts not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of this disclosure.

[0005] Some embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. These embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0006] For use cases where User Equipment (UEs) from the same or different Home Public Land Mobile Networks (HPLMNs) establish Home Routing Protocol Data Unit (PDU) sessions using the same private UE Internet Protocol (IP) address, there are currently some challenges in Home Routing Session Offloading (HR-SBO) scenarios. As mentioned above, if these UEs are roaming in the same Visited Public Land Mobile Network (VPLMN) supporting Home Routing Session Offloading (HR-SBO) and are assigned the same Visited User Plane Function (V-UPF) and the same Visited Edge Application Server Discovery Function (V-EASDF), then if these UEs are assigned the same private IP address, it will cause problems for V-EASDF to distinguish these UE / PDU sessions. The 3GPP Technical Specification (TS) 23.548 has proposed three candidate solutions to this problem: an N6 tunnel-based solution, a network instance-based solution, and a UE source IP address mapping solution. These three candidate solutions are referred to in this document as Option A (N6 tunnel), Option B (network instance), and Option C (UE source IP address mapping).

[0007] For option B, the same UE IP address can be associated with different network instances. Therefore, services directed to different UEs can be distinguished.

[0008] For Option A, this candidate solution suggests using an N6 tunnel between the User Plane Function (UPF) and the Edge Application Server Discovery Function (EASDF). As shown in 3GPP TS 29.556 and 23.548, the Visiting Session Management Function (V-SMF) (i.e., the session management function in the VPLMN) can provide N6 tunnel information. How the V-SMF obtains such N6 tunnel information is an unresolved issue. Potentially, such information can be articulated or configured locally. However, this adds a significant amount of configuration work, leading to substantial operational costs and difficulty in maintenance.

[0009] For option C, this candidate solution suggests replacing incoming packets with the same UE IP address with a new IP address provided by the IP pool of the local PSA UPF. Similarly, 3GPP TS 29.556 and 23.548 explicitly state that the SMF can set the UE IP address as a mapped address. Therefore, the SMF or UPF, which has locally configured IP pool information, controls the IP pool. If the UPF provides IP pool information, this information should also be provided during the registration process, and the IP pool information can also be used by the SMF when it selects such a UPF.

[0010] Therefore, during Network Store Function (NRF) discovery, both the UPF and EASDF need to contain supported tunnel information. When the SMF selects the UPF and then the corresponding EASDF, tunnel information also needs to be available at the SMF. However, in the current implementation, as defined in sections 6.1.6.2.15 and 6.1.6.2.77 of 3GPP 29.510 (see below), there is no information regarding tunnel information during NRF discovery. Therefore, the SMF lacks N6 tunnel information and cannot complete this process.

[0011] For option C, the UPF needs to have knowledge of the IP pool range during NRF discovery for HR-SBO. However, such information is not specified in Clause 6.1.6.2.15 of 3GPP TS 29.510 (see below).

[0012] Therefore, in the current specification, options A and C are incomplete, and the UPF / EASDF without N6 tunnel information and / or IP pool information is insufficient to support DNS service routing for UEs with the same IP address from multiple DNNs.

[0013] In principle, the proposal described in C4-240329 is correct; however, the current 3GPP specification does not define: a. How will SMF know which IP address and port on the UPF side and which IP address and port on the EASDF side to establish this point-to-point N6 tunnel, i.e., provided in the creation of the external header for the tunnel IP address and port? b. How will the SMF know which IP address in the UPF can be used as the N6 address for mapping those PDU sessions that have the same assigned private UE IP address? c. How will SMF know whether these IP addresses (whether tunneled IP addresses or mapped N6 addresses) should always be allocated from the pool by SMF?

[0014] Furthermore, when the tunnel on N6 between EASDF and UPF is used to separate different PDU sessions with the same private UE IP address, how to instruct EASDF to decapsulate payload packets (e.g., DNS query request messages) received from the tunnel (between V-UPF and V-EASDF) and encapsulate payload packets (e.g., DNS query response messages) into the tunnel is also a problem that needs to be solved.

[0015] For reference, the following content is currently defined in the 3GPP specifications: 6.1.6.2.15 Type: DnnUpfInfoItem Table 6.1.6.2.15-1: Definition of type DnnUpfInfoItem 6.1.6.2.77 Type: EasdfInfo Table 6.1.6.2.77-1: Definition of type EasdfInfo

[0016] Certain aspects of this disclosure and its embodiments may provide solutions to these or other challenges.

[0017] Specifically, some embodiments of this disclosure provide a mechanism that enables the V-SMF (SMF in VPLMN) to obtain sufficient information to configure (i.e., set) the tunnel on N6 between the V-UPF and V-EASDF, or to perform IP substitution between the private UE IP address and the mapped N6 address, so that the V-EASDF will be able to distinguish DNS traffic from UEs with the same private IP address and apply different DNS rules for different PDU sessions.

[0018] One embodiment relates to a method for Home Route (HR) Session Offloading (SBO) of Protocol Data Unit (PDU) sessions for User Equipment (UE) using Private Internet Protocol (IP) addresses, performed by the Visiting Session Management Function (V-SMF) in a Visiting Public Land Mobile Network (VPLMN). The method includes: obtaining ( Figure 1 Steps 5 and 6; Figure 2 Steps 1 and 2 or steps 3 and 4; Figure 3 Steps 1 and 2 or steps 3 and 4; Figure 5 Steps 1 and 2; Figure 6 Steps 1 and 2) provide tunnel information for establishing a tunnel (e.g., HR-SBO for the PDU session of the UE using the private IP address) between the Visiting User Plane Function (V-UPF) and the Visiting Edge Application Server Discovery Function (V-EASDF); and based on the obtained tunnel information, perform ( Figure 6 Step 1 or Step 3; Figure 7 (Step 1 and / or Step 2) one or more operations, the one or more operations involving establishing a tunnel between V-UPF and V-EASDF (e.g., HR-SBO for the PDU session of the UE using the private IP address).

[0019] Another embodiment relates to a method performed by a UPF. The method includes: sending (…) to a Network Storage Function (NRF) Figure 1 , 0A) request, wherein the request is an NF profile registration request or an NF profile update request, and the request includes tunnel information for the UPF (e.g., tunnel information for establishing a tunnel between the UPF and EASDF (e.g., for an HR-SBO PDU session of a UE using a private IP address)).

[0020] Another embodiment relates to a method performed by the Edge Application Server Discovery Function (EASDF). The method includes: sending (…) to the Network Repository Function (NRF) Figure 1 ,0C) request, wherein the request is an NF profile registration request or an NF profile update request, and the request includes tunnel information for the EASDF (e.g., tunnel information for establishing a tunnel between the EASDF and the UPF (e.g., for an HR-SBO PDU session of a UE using a private IP address)).

[0021] Another embodiment relates to a method for Home Routing (HR) Session Offloading (SBO) for a PDU session of a UE using a Private Internet Protocol (IP) address, performed by a V-SMF in a VPLMN. The method includes: obtaining ( Figure 8Steps 5 and 6) IP replacement pool information, for use in uplink services of the HR-SBOPDU session, to replace the source IP address of the UE's HR-SBOPDU session with a mapped (e.g., N6) IP address, where the source IP address is a private UE IP address.

[0022] Another embodiment relates to a method performed by a User Plane Function (UPF). The method includes: sending (…) to a Network Storage Function (NRF) Figure 8 , 0A) request, wherein the request is an NF profile registration request or an NF profile update request, and the request includes IP replacement pool information for the UPF (e.g., IP replacement pool information for source IP address replacement (e.g., for HR-SBO PDU sessions of UEs using private IP addresses). Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of this disclosure and, together with the specification, serve to explain the principles of this disclosure. Figure 1 This illustrates the process by which V-UPF and V-EASDF register their NF profiles with the NRF in VPLMN; Figure 2 The operation of V-SMF and V-UPF according to an example embodiment of alternative 1 (b1) is shown; Figure 3 The operation of V-SMF and V-UPF according to an example embodiment of alternative 1 (b2) is shown; Figure 4 The operation of V-SMF and V-EASDF according to an example embodiment of alternative 1 (c1) is shown; Figure 5 The operation of V-SMF and V-EASDF according to an example embodiment of alternative 1 (c2) is shown; Figure 6 The operation of V-SMF and V-EASDF according to an example embodiment of alternative 1(D) is shown; Figure 7 The operation of V-UPF, V-EASDF and V-SMF according to an example embodiment of alternative 1(E) is shown; Figure 8 The process is illustrated according to an example embodiment of alternative scheme 2(A); Figure 9 The process is illustrated according to an example embodiment of alternative scheme 2 (b1); Figure 10 The process is shown according to an example embodiment of alternative scheme 2 (b2); Figure 11 A reference architecture for fifth-generation (5G) systems (5GS) is shown; Figure 12 This is a schematic block diagram of a network node 1200 according to some embodiments of the present disclosure; Figure 13 This is a schematic block diagram illustrating a virtualized embodiment of a network node 1200 according to some embodiments of the present disclosure. Detailed Implementation

[0024] Embodiments of this disclosure may include any one or more of the following "alternatives": • Alternative Option 1: V-SMF can determine the IP address and optional port number range used to establish a tunnel between V-UPF and V-EASDF. This can include any one or more of the following: ○ Alternative Option 1 (A): V-UPF and V-EASDF can include such IP address and port number ranges in their Network Function (NF) profiles registered with the NRF so that V-SMF will obtain this information when V-UPF and V-EASDF are selected during the NF (Service) discovery process; or ○ Alternatives 1(b1) and 1(b2): b1. When establishing / updating a PFCP association between V-SMF and V-UPF, V-UPF may report the range of IP addresses and port numbers used for tunnel establishment on the V-UPF side in the PFCP association establishment request / response and update request / response messages, for example via a new information element (IE) or an extended existing IE (e.g., UE IP address pool information); or b2. When V-SMF establishes / updates a PFCP session for a home route PDU session using a private UE IP address, V-UPF returns the tunnel IP address in the PFCP session establishment / modification response and indicates that tunnel information needs to be allocated; or ○ Alternatives 1 (c1) and 1 (c2): V-EASDF can report the range of IP addresses and port numbers used for tunnel establishment on the V-EASDF side to the SMF during the baseline DNS mode establishment process; or c2. When V-SMF calls the Neasdf_DNSContext service to create a separate DNS context for a home route PDU session using a private UE IP address, V-EASDF can return the tunnel IP address in the DNS context creation response message and indicate that tunnel information needs to be allocated; ○ Alternative Option 1 (D): Corresponding to A or c1, when V-SMF selects tunnel information on the V-EASDF side, it should indicate the selected tunnel information to V-EASDF in the DNS context creation or update request message; ○ Alternative Option 1 (E): Corresponding to c2 or D, V-SMF provides instructions to V-EASDF so that V-EASDF: ■ Retrieve the DNS query message as the uplink payload from the tunnel (between V-UPF and V-EASDF) by removing the external IP header and User Datagram Protocol (UDP) header (if available), where the source IP address is the UPF tunnel IP, the source port is the UPF port, the destination IP address is the EASDF tunnel IP address, and the destination port is the EASDF UDP port. ■ Store the source IP address (i.e., UPF tunnel IP) and source port (i.e., UPF port) that will be used for downlink services. ■ By adding an external IP header, the DNS response message is placed as a downlink payload into the tunnel (between V-UPF and V-EASDF), where the destination IP address is the UPF tunnel IP and the destination port is the UPF port. • Alternative Option 2: V-SMF can determine the range of IP addresses and port numbers used for IP replacement. Specifically, for uplink services, it can replace the source IP address of the private UE IP address with the mapped N6 address, and for downlink services, it can replace the destination IP address of the mapped N6 address back to the private UE IP address. This can include any one or more of the following: Alternative Option 2 (A): V-UPFs may include such IP address and port number ranges in their NF profiles registered with the NRF for the aforementioned purposes, so that the SMF will obtain this information when a V-UPF is selected during the NF (Service) Discovery process; or ○ Alternatives 2 (b1) and 2 (b2): b1. When establishing / updating a PFCP association between V-SMF and V-UPF, V-UPF may report the range of IP addresses and port numbers used for IP replacement on the V-UPF side in the PFCP association establishment request / response and update request / response messages, for example via a new IE or an extended existing IE (e.g., UE IP address pool information); or b2. When V-SMF establishes a PFCP session for a home route PDU session using a private UE IP address, V-UPF returns the mapped IP address in the PFCP session establishment / modification response and indicates that such a mapped N6 IP address needs to be allocated.

[0025] Embodiments of this disclosure may include any one or more of the following aspects: 1. Register the tunnel IP address and port number range information for establishing (IP / UDP) tunnels between UPF and EASDF for HR-SBO in the NRF used for V-UPF and V-EASDF. 2. Register the range of mapped N6 IP addresses in the NRF used for V-UPF to enable IP replacement. 3. During PFCP association-related processes, V-UPF reports to SMF the tunnel IP address and port number range information used to establish (IP / UDP) tunnels between UPF and EASDF, or provides tunnel information during the establishment or modification of PFCP sessions for PDU sessions; 4. During the PFCP association process, V-UPF reports to SMF the N6 IP address range information for IP replacement mapping, or, if requested by SMF, provides tunneling information during the establishment or modification of a PFCP session for a PDU session. 5. V-EASDF reports to SMF during the creation of the DNS baseline pattern the tunnel IP address and port number range information used to establish an (IP / UDP) tunnel between UPF and EASDF, or, if requested by SMF, provides tunnel information during the creation of the DNS context for a separate PDU session. 6. V-SMF instructs V-EASDF to decapsulate payload packets (e.g., DNS query request messages) received from the tunnel (between V-UPF and V-EASDF) and encapsulate payload packets (e.g., DNS query response messages) into the tunnel.

[0026] Certain embodiments may provide one or more of the following technical advantages. Embodiments of this disclosure provide a mechanism that enables the V-SMF (SMF in a VPLMN) to obtain sufficient information to configure / set up a tunnel on N6 between the V-UPF and V-EASDF, or to perform IP substitution between a private UE IP address and a mapped N6 address, so that the V-EASDF will be able to distinguish DNS traffic from UEs with the same private IP address, and apply different DNS rules for different PDU sessions. Figure 11

[0027] Figure 11 It is 3GPP TS 23.548 V18.4.0. Figure 4 The reproduction of .2-5 illustrates a reference architecture for a fifth-generation (5G) system (5GS) that provides access to the Edge Application Server (EAS) for HR-SBO roaming scenarios. Embodiments of this disclosure can be implemented according to... Figure 11 The architecture is implemented in 5GS; however, embodiments of this disclosure are not limited to... Figure 11 The architecture. Regarding... Figure 11 More details about the architecture can be found in, for example, 3GPP TS 23.548.

[0028] A more detailed description of embodiments of this disclosure will now be provided. This description is provided for the various "alternatives" described above. Alternative Option 1

[0029] In Alternative Option 1, V-SMF is able to obtain the IP address and optional port number range used to establish a tunnel between V-UPF and V-EASDF. Alternative Option 1 (A): Figure 1

[0030] In alternative 1(A), V-UPF and V-EASDF can include such IP address and port number ranges in their NF profiles registered with the NRF. In this regard, Figure 1 The process of V-UPF and V-EASDF registering their NF profiles to the NRF in the VPLMN according to an example embodiment of alternative 1 (A) is illustrated, wherein the NF profile includes an IP address and an optional range of port numbers. Figure 1 The process steps are as follows: • Step 0A: The V-UPF sends an NF profile registration request or NF profile update request to the NRF in the VPLMN to register (i.e., create) or update the NF profile of the V-UPF stored by the NRF for the V-UPF. The V-UPF's NF profile includes tunnel information, which may include, for example, an IP address range and an optional port number range. • Step 0B: The NRF sends a response to the V-UPF indicating that the V-UPF's NF profile has been successfully created or updated. • Step 0C: V-EASDF sends an NF profile registration request or NF profile update request to the NRF in the VPLMN to register (i.e., create) or update the NF profile of V-EASDF stored by the NRF for V-EASDF. The V-EASDF's NF profile includes tunnel information, which may include, for example, an IP address range and an optional port number range. • Step 0D: The NRF sends a response to the V-EASDF indicating that the V-EASDF's NF profile has been successfully created or updated. • Step 1: The UE sends a PDU session establishment request to the V-SMF for the Home Routing (HR) PDU session. • Step 2: The V-SMF sends a PDU session creation request to the H-SMF (i.e., the SMF in the HPLMN) and receives a PDU session creation response from the H-SMF. In this response, the HR-SBO is authorized along with the VPLMN offload policy. The V-SMF learns that a private UE IP address is being used. • Step 4: V-SMF decides to select UPF (i.e., V-UPF) and V-EASDF to support HR-SBO functionality. • Step 5: The V-SMF sends a discovery request to the NRF in the VPLMN. This discovery request must include at least the query parameter NF type, which is set to UPF or EASDF. • Step 6: The NRF sends a discovery response to the V-SMF, which includes an NF profile for one or more candidate UPFs (if the NF type in the discovery request is set to UPF) and / or an NF profile for one or more candidate EASDFs (if the NF type in the discovery request is set to EADF). • V-SMF selects V-UPF and V-EASDF to continue the PFCP process or the Neasdf_DNSContextCreate request.

[0031] Below are modified versions of the definitions for types DnnUpfInoItem and EasdfInfo, which include tunnel information. Added content is indicated by underlined text. This information can be included in the V-UPF NF profile and the V-EASDF NF profile, respectively. 6.1.6.2.15 Type: DnnUpfInfoItem Table 6.1.6.2.15-1: Definition of type DnnUpfInfoItem • 6.1.6.2.77 Type: EasdfInfo Table 6.1.6.2.77-1: Definition of EasdfInfo type Alternative Option 1 (b1) Figure 2

[0032] In alternative solution 1 (b1), V-UPF can report the range of IP addresses and port numbers used for tunnel establishment on the V-UPF side in the PFCP association establishment request / response and update request / response messages. In this regard, Figure 2 The operation of V-SMF and V-UPF according to an example embodiment of alternative 1 (b1) is shown. • Step 1: V-SMF sends a PFCP association establishment request to V-UPF. • Step 2: V-UPF sends a PFCP association establishment response to V-SMF, which includes tunnel information, such as the range of IP addresses and optional port numbers used to establish the tunnel on the V-UPF side. • Supplements or alternatives to steps 1 and 2: Step 3: V-SMF sends a PFCP association update request to V-UPF. Step 4: V-UPF sends a PFCP association update response to V-SMF, which includes (potentially updated) tunnel information, such as the range of IP addresses and optional port numbers used to establish the tunnel on the V-UPF side. Alternative Option 1 (b2) Figure 3

[0033] In alternative scheme 1 (b2), when V-SMF establishes / updates a PFCP session for a home route PDU session using a private UE IP address, V-UPF returns the tunnel IP address in the PFCP session establishment / modification response and indicates that tunnel information needs to be allocated. In this regard, Figure 3 The operation of V-SMF and V-UPF according to an example embodiment of alternative 1 (b2) is shown. The steps of the procedure are as follows: • Step 1: The V-SMF sends a PFCP session establishment request to the V-UPF for the HR-SBO PDU session using a private IP address. This request includes an indicator that the V-SMF is requesting tunnel information (e.g., requesting tunnel allocation information). • Step 2: V-UPF sends a PFCP session establishment response to V-SMF, which includes the requested tunnel information, such as a specific IP address and optional port number for the HR-SBO PDU session. • Supplements or alternatives to steps 1 and 2: Step 3: The V-SMF sends a PFCP session modification request to the V-UPF for the HR-SBO PDU session using a private IP address. This request includes an indicator that the V-SMF is requesting tunnel information (e.g., requesting tunnel allocation information). Step 4: V-UPF sends a PFCP session modification response to V-SMF, which includes the requested tunnel information, such as a specific IP address and optional port number for the HR-SBO PDU session. Alternative Option 1 (c1) Figure 4

[0034] In alternative option 1 (c1), V-EASDF can report the range of IP addresses and port numbers used for tunnel establishment on the V-EASDF side to the V-SMF during the baseline DNS mode establishment process. In this regard, Figure 4 The operation of V-SMF and V-EASDF according to an example embodiment of alternative 1 (c1) is shown. The steps of the procedure are as follows: • Step 1: V-SMF sends a baseline DNS mode establishment request to V-EASDF. • Step 2: V-EASDF sends data to V-SMF regarding the requested baseline DSN pattern, which includes tunnel information from V-EASDF, such as IP address ranges and optional port number ranges. Alternative Option 1 (c2) Figure 5

[0035] In alternative scheme 1 (c2), when V-SMF calls the Neasdf_DNSContext service to create a separate DNS context for a home route PDU session using a private UE IP address, V-EASDF can return the tunnel IP address in the DNS context creation response message and indicate that tunnel information needs to be allocated. In this regard, Figure 5 The operation of V-SMF and V-EASDF according to an example embodiment of alternative 1 (c2) is shown. The steps of the procedure are as follows: • Step 1: The V-SMF sends a DNS Context Creation Request to the V-EASDF to create a separate DNS context for the HR-SBO PDU session. This request includes an indicator that the V-SMF is requesting the allocation of tunnel information (e.g., allocating a tunnel IP address and an optional port number). • Step 2: V-EASDF sends a response to V-SMF, which includes the requested tunnel information, such as a specific IP address and optional port number for the HR-SBOPDU session. Alternative Option 1 (D) Figure 6

[0036] In Alternative Option 1 (D), in conjunction with Alternative Option 1 (A) or Alternative Option 1 (c1), when the V-SMF selects tunnel information on the V-EASDF side, it should indicate the selected tunnel information to the V-EASDF in the DNS context creation or update request message. In this regard, Figure 6The operation of V-SMF and V-EASDF according to an example embodiment of alternative 1(D) is shown. The steps of the process are as follows: • Step 1: As shown in the figure, V-SMF sends a DNS Context Creation Request to V-EASDF to create a separate DNS context for the HR-SBO PDU session. As shown in the figure, this request includes the selected tunnel information, such as a specific tunnel IP address and an optional port number. • Step 2: V-EASDF sends a response to V-SMF indicating that the requested DNS context has been created. • Supplements or alternatives to steps 1 and 2: Step 3: V-SMF sends a DNS Context Update Request to V-EASDF to update the DNS context separately for the HR-SBO PDU session. As shown in the figure, this request includes the selected tunnel information, such as the specific tunnel IP address and optional port number. Step 4: V-EASDF sends a response to V-SMF indicating that the requested DNS context has been updated. Alternative Option 1 (E) Figure 7

[0037] In Alternative Option 1 (E), in conjunction with Alternative Option 1 (c2) or Alternative Option 1 (D), the V-SMF provides the V-EASDF with instructions for processing payload traffic originating from / entering the tunnel, wherein such instructions are at least flagged. In this regard, Figure 7 The operation of V-UPF, V-EASDF, and V-SMF according to an example embodiment of alternative 1(E) is shown. The steps of the procedure are as follows: • Step 0: After retrieving tunnel information (e.g., IP address and optional port number for the tunnel) from the NRF or from the V-UPF and V-EASDF, the V-SMF needs to establish a tunnel between the V-UPF and V-EASDF. • Step 1: V-SMF sends a PFCP session modification request to V-UPF and receives the corresponding PFCP session modification response from V-UPF. In this process, V-SMF instructs V-UPF to put the DNS query into a tunnel toward V-EASDF and extract the DNS response from the tunnel via external header creation and external header removal. • Step 2: V-SMF updates the DNS context and instructs V-EASDF to extract the DNS query from the tunnel and encapsulate the DNS response into the tunnel via a new instruction. • Step 3: Use the retrieved tunnel information to establish a tunnel on N6 between V-UPF and V-EASDF. • Step 4: V-UPF sends an uplink payload (e.g., a DNS query) encapsulated in a tunnel, where the V-UPF tunnel IP address is set to the source IP address, the V-UPF port is set to the source port, the V-EASDF tunnel IP address is set to the destination IP address, and the V-EASDF port is set to the destination port. • Step 5: When extracting payload packets from the tunnel, V-EASDF stores the source IP address and source port (i.e., V-UPF tunnel IP address and port) that will be used for downlink services. • Step 6: When a DNS query response is received from the DNS server, V-EASDF uses the V-UPF tunnel IP address as the destination IP address and the V-UPF port as the destination port to encapsulate the payload packet into the tunnel. • Step 7: V-EASDF sends a downlink payload (e.g., a DNS query response) encapsulated in the tunnel to V-UPF, where the V-UPF tunnel IP address is set to the destination IP address, the V-UPF port is set to the destination port, the V-EASDF tunnel IP address is set to the source IP address, and the V-EASDF port is set to the source port. Alternative Option 2

[0038] In Alternative Option 2, V-SMF can obtain the range of IP addresses and port numbers used for IP replacement. That is, for uplink services, it can replace the source IP address of the private UE IP address with the mapped N6 address, and for downlink services, it can replace the destination IP address of the mapped N6 address back with the private UE IP address. Alternative Option 2 (A) Figure 8

[0039] In alternative 2(A), V-UPF may include such a range of IP addresses and port numbers in its NF profile for the aforementioned purposes, so that V-SMF will obtain this information when V-UPF is selected during the NF (Service) Discovery process. In this regard, Figure 8 A process according to an example embodiment of alternative 2(A) is shown. The steps of the process are as follows: • Step 0A: The V-UPF sends an NF profile registration request or NF profile update request to the NRF in the VPLMN to register (i.e., create) or update the NF profile of the V-UPF stored by the NRF for the V-UPF. The V-UPF's NF profile includes an IP replacement pool, such as an IP address range and an optional port number range. • Step 0B: The NRF sends a response to the V-UPF indicating that the V-UPF's NF profile has been successfully created or updated. • Step 1: The UE sends a PDU session establishment request to the V-SMF for the Home Routing (HR) PDU session. • Step 2: The V-SMF sends a PDU session creation request to the H-SMF (i.e., the SMF in the HPLMN) and receives a PDU session creation response from the H-SMF. In this response, the HR-SBO is authorized along with the VPLMN offload policy. The V-SMF learns that a private UE IP address is being used. • Step 4: V-SMF decides to select UPF (i.e., V-UPF) to support HR-SBO functionality. • Step 5: The V-SMF sends a discovery request to the NRF in the VPLMN. This discovery request must include at least the query parameter NF type set to UPF. • Step 6: The NRF sends a discovery response to the V-SMF, which includes NF profiles for one or more candidate UPFs. Here, the candidate UPFs include the V-UPF. • V-SMF continues the PFCP process to establish a PFCP session for the PDU session. Alternative Option 2 (b1) Figure 9

[0040] In alternative scheme 2 (b1), when establishing / updating a PFCP association between the V-SMF and V-UPF, the V-UPF can report the range of IP addresses and port numbers used for IP replacement on the V-UPF side in the PFCP association establishment request / response and update request / response messages, for example via a new IE or an extended existing IE (e.g., UE IP address pool information). In this regard, Figure 9 A process according to an example embodiment of alternative scheme 2 (b1) is shown. The steps of the process are as follows: • Step 1: V-SMF sends a PFCP association establishment request to V-UPF. • Step 2: V-UPF sends a PFCP association establishment response to V-SMF, which includes replacement IP pool information, such as IP address range and optional port number range. • Supplements or alternatives to steps 1 and 2: Step 3: V-SMF sends a PFCP association update request to V-UPF. Step 4: V-UPF sends a PFCP association update response to V-SMF, which includes replacement IP pool information, such as IP address range and optional port number range. Alternative Option 2 (b2) Figure 10

[0041] In alternative scheme 2 (b2), when the V-SMF establishes a PFCP session for a home route PDU session using a private UE IP address, the V-UPF returns the mapped IP address in the PFCP session establishment / modification response and indicates that such a mapped N6 IP address needs to be allocated. In this regard, Figure 10 A process according to an example embodiment of alternative scheme 2 (b2) is shown. The steps of the process are as follows: • Step 1: The V-SMF sends a PFCP session establishment request to the V-UPF for the HR-SBO PDU session using a private IP address. This request includes an indicator that the V-SMF is requesting a mapped IP address. • Step 2: V-UPF sends a PFCP session establishment response to V-SMF, which includes the requested mapped IP address, for example, a specific IP address for an HR-SBO PDU session and an optional port number. • Supplements or alternatives to steps 1 and 2: Step 3: The V-SMF sends a PFCP session modification request to the V-UPF for the HR-SBO PDU session using a private IP address. This request includes an indicator that the V-SMF is requesting a mapped IP address. Step 4: V-UPF sends a PFCP session modification response to V-SMF, which includes the requested mapped IP address, for example, a specific IP address for an HR-SBO PDU session and an optional port number. Further description Figure 12

[0042] Figure 12This is a schematic block diagram of a network node 1200 according to some embodiments of the present disclosure. Optional features are indicated by dashed boxes. The network node 1200 may be, for example, a network node implementing network functions (NF) or a core network node, such as, for example, V-UPF, V-SMF, V-EASDF, NRF, etc., as described herein. As shown, the network node 1200 includes one or more processors 1204 (e.g., a central processing unit (CPU), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), etc.), memory 1206, and network interface 1208. The one or more processors 1204 are also referred to herein as processing circuitry. The one or more processors 1204 operate to provide one or more functions of the network node 1200 as described herein (e.g., one or more functions of V-UPF, V-SMF, V-EASDF, NRF, etc., as described herein). In some embodiments, the functions are implemented in software, which is stored, for example, in memory 1206 and executed by one or more processors 1204. Figure 13

[0043] Figure 13 This is a schematic block diagram illustrating a virtualized embodiment of network node 1200 according to some embodiments of the present disclosure. Similarly, optional features are indicated by dashed boxes. As used herein, a “virtualized” network node is an implementation of network node 1200 in which at least a portion of the functionality of network node 1200 is implemented as a virtual component (e.g., via a virtual machine executing on a physical processing node in the network). As shown, network node 1200 includes one or more processing nodes 1300 that are coupled to or included as part of network 1302. Each processing node 1300 includes one or more processors 1304 (e.g., CPU, ASIC, FPGA, etc.), memory 1306, and network interface 1308. In this example, the functionality 1310 of network node 1200 described herein (such as one or more functions of V-UPF, V-SMF, V-EASDF, NRF, etc. described herein) is implemented at one or more processing nodes 1300 in any desired manner. In some specific embodiments, some or all of the functions 1310 of the network node 1200 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual environment hosted by the processing node 1300. As those skilled in the art will understand, additional signaling or communication between the processing node 1300 and the control system 1202 is used to perform at least some of the required functions 1310. It is worth noting that in some embodiments, the control system 1202 may be omitted, in which case the radio unit 1210 communicates directly with the processing node 1300 via a suitable network interface.

[0044] In some embodiments, a computer program including instructions is provided that, when executed by at least one processor, cause the at least one processor to perform the functions of network node 1200 or a node (e.g., processing node 1300) that implements one or more functions 1310 of network node 1200 in a virtual environment, according to any of the embodiments described herein. In some embodiments, a carrier including the above-described computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium such as a memory). Example

[0045] The embodiments described above can be summarized as follows: 1. A method performed by the Visiting Session Management Function (V-SMF) in a Visiting Public Land Mobile Network (PLMN) for Home Routing (HR) Session Offloading (SBO) of Protocol Data Unit (PDU) sessions of a User Equipment (UE) using a Private Internet Protocol (IP) address, the method comprising: get( Figure 1 Steps 5 and 6; Figure 2 Steps 1 and 2 or steps 3 and 4; Figure 3 Steps 1 and 2 or steps 3 and 4; Figure 5 Steps 1 and 2; Figure 6 Steps 1 and 2) provide tunnel information for establishing a tunnel between the Visiting User Plane Function (V-UPF) and the Visiting Edge Application Server Discovery Function (V-EASDF) (e.g., for HR-SBO of the PDU session of the UE using the private IP address); and Based on the obtained tunnel information, execute ( Figure 6 Step 1 or Step 3; Figure 7 (Step 1 and / or Step 2) one or more operations, the one or more operations involving establishing a tunnel between the V-UPF and the V-EASDF (e.g., HR-SBO for the PDU session of the UE using the private IP address). 2. The method according to Embodiment 1, wherein the tunnel information includes an IP address range for establishing a tunnel between the V-UPF and the V-EASDF. 3. The method according to Embodiment 1, wherein the tunnel information includes an IP address range and a port range for establishing a tunnel between the V-UP and the V-EASDF. 4. The method according to any one of Examples 1 to 3, wherein ( Figure 1 The tunnel information mentioned in steps 5 and 6) includes: Send to the Network Refrigeration Function (NRF) in the VPLMN ( Figure 1 Step 5) Discover the request; Received from the NRF ( Figure 1 Step 6) Discovery response, the discovery response including the NF profile of each of one or more candidate V-UPFs, wherein the V-UPF is the selected candidate V-UPF among the one or more candidate V-UPFs, and the NF profile of the V-UPF includes the tunnel information. 5. The method according to any one of Examples 1 to 3, wherein ( Figure 1 The tunnel information mentioned in steps 5 and 6) includes: Send to the Network Refrigeration Function (NRF) in the VPLMN ( Figure 1 Step 5) Discover the request; Received from the NRF ( Figure 1 Step 6) Discover the response, which includes the NF profile of each candidate V-UPF in one or more candidate V-UPFs and each candidate V-EASDF in one or more candidate V-EASDFs; in: The V-UPF is a selected candidate V-UPF from the one or more candidate V-UPFs; The V-EASDF is a selected candidate V-EASDF from the one or more candidate V-EASDFs; and The obtained tunnel information includes first tunnel information included in the NF profile of the V-UPF and second tunnel information included in the NF profile of the V-EASDF. 6. The method according to any one of Examples 1 to 3, wherein ( Figure 2 The tunnel information mentioned in steps 1 and 2 or steps 3 and 4) includes: Send to the V-UPF ( Figure 2 Step 1 or 3) Request, wherein the request is a PFCP association establishment request or a PFCP association modification request; Receive from the V-UPF ( Figure 2 Step 2 or 4) response, the response including the tunnel information. 7. The method according to any one of Examples 1 to 3, wherein ( Figure 3 The tunnel information mentioned in steps 1 and 2 or steps 3 and 4) includes: Send to the V-UPF ( Figure 3 Step 1 or 3) Request, wherein the request is a PFCP session establishment request or a PFCP session modification request; Receive from the V-UPF ( Figure 3 Step 2 or 4) response, the response including the tunnel information. 8. The method according to any one of Examples 1 to 3, wherein ( Figure 4 Step 2) The tunnel information includes: Received from the V-EASDF during the baseline DNS mode establishment process ( Figure 4 The tunnel information described in step 2) (e.g., as part of the baseline DNS schema creation response). 9. The method according to any one of embodiments 1 to 3, wherein, obtaining ( Figure 5 Step 2) The tunnel information includes: Received from the V-EASDF during the DNS context creation process ( Figure 5 The tunnel information described in step 2) (e.g., as part of the DNS context creation response). 10. The method according to any one of Embodiments 1 to 9 (more specifically, the method according to any one of Embodiments 1 to 4 or 7), wherein, based on the obtained tunnel information, the following is performed: Figure 6 The one or more operations described in step 1 or step 3) include: Send to the V-EASDF ( Figure 5 Step 1 or 3) DNS context related request, wherein the DSN context related request is a DNS context creation request or a DNS context update request, and the DSN context related request includes tunnel information selected from the obtained tunnel information. 11. The method according to embodiment 10, wherein the obtained tunnel information includes an IP address range, and the selected tunnel information includes an IP address selected from the IP address range. 12. The method according to embodiment 10, wherein the obtained tunnel information includes an IP address range and a port number range, and the selected tunnel information includes an IP address selected from the IP address range and a port number selected from the port number range. 13. The method according to any one of Examples 1 to 12 (more specifically, the method according to any one of Examples 8, 10, 11 or 12), wherein the following is performed: Figure 6 The one or more operations described in step 1 or step 3) include: Send to the V-UPF ( Figure 7Step 1) is an instruction (e.g., in a PFCP session modification request) for the V-UPF to send the associated DNS query to the tunnel established between the V-UPF and the V-EASDF and to extract the associated DNS response from the tunnel. 14. The method according to any one of Examples 1 to 13 (more specifically, the method according to any one of Examples 8, 10, 11, 12 or 13), wherein, performing ( Figure 6 The one or more operations described in step 1 or step 3) include: Send to the V-EASDF ( Figure 7 Step 2) is an instruction for the V-EASDF to extract the associated DNS query from the tunnel established between the V-UPF and the V-EASDF, and to send the associated DNS response via the tunnel (e.g., in a DNS context update). 15. A network node adapted to perform the method according to any one of embodiments 1 to 14. 16. A method performed by a User-Plane Function (UPF), the method comprising: Send to Network Memory Function (NRF) Figure 1 , 0A) request, wherein the request is an NF profile registration request or an NF profile update request, and the request includes tunnel information for the UPF (e.g., tunnel information for establishing a tunnel between the UPF and EASDF (e.g., for an HR-SBO PDU session of a UE using a private IP address)). 17. The method according to embodiment 16, wherein the tunnel information includes an IP address range for establishing a tunnel (e.g., a tunnel between the UPF and EASDF). 18. The method according to embodiment 16, wherein the tunnel information includes an IP address range and a port range for establishing a tunnel (e.g., a tunnel between the UPF and EASDF). 19. A network node adapted to perform the method according to any one of embodiments 15 to 18. 20. A method performed by the Edge Application Server Discovery Function (EASDF), the method comprising: Send to Network Memory Function (NRF) Figure 1 ,0C) request, wherein the request is an NF profile registration request or an NF profile update request, and the request includes tunnel information for the EASDF (e.g., tunnel information for establishing a tunnel between the EASDF and the UPF (e.g., for an HR-SBO PDU session of a UE using a private IP address)). 21. The method according to embodiment 16, wherein the tunnel information includes an IP address range for establishing a tunnel (e.g., a tunnel between the EASDF and the UPF). 22. The method according to embodiment 16, wherein the tunnel information includes an IP address range and a port range for establishing a tunnel (e.g., a tunnel between the EASDF and the UPF). 23. A network node adapted to perform the method according to any one of embodiments 20 to 22. 24. A method performed by the Visiting Session Management Function (V-SMF) in a Visiting Public Land Mobile Network (PLMN) for Home Routing (HR) Session Offloading (SBO) of Protocol Data Unit (PDU) sessions of a User Equipment (UE) using a Private Internet Protocol (IP) address, the method comprising: get( Figure 8 Steps 5 and 6) IP replacement pool information, for use in uplink services of the HR-SBO PDU session, to replace the source IP address of the UE's HR-SBO PDU session with a mapped (e.g., N6) IP address, where the source IP address is a private UE IP address. 25. The method according to embodiment 24 further includes: performing one or more operations based on the obtained IP replacement pool, the one or more operations relating to: replacing the source IP address of the HR-SBO PDU session of the UE with a mapped (e.g., N6) IP address (selected from the IP replacement pool) for uplink services of the HR-SBO PDU session, the source IP address being the private UE IP address; and mapping the mapped IP address back to the private UE IP address for downlink services of the HR-SBO PDU session. 26. The method according to embodiment 24 or 25, wherein the IP replacement pool information includes an IP address range. 27. The method according to embodiment 24 or 25, wherein the IP replacement pool information includes an IP address range and a port range. 28. The method according to any one of Examples 24 to 27, wherein ( Figure 8 Steps 5 and 6) include IP replacement pool information: Send to the Network Refrigeration Function (NRF) in the VPLMN ( Figure 8 Step 5) Discover the request; Received from the NRF ( Figure 8Step 6) Discovery response, the discovery response including the NF profile of each of one or more candidate V-UPFs, wherein the V-UPF is the selected candidate V-UPF among the one or more candidate V-UPFs, and the NF profile of the V-UPF includes the IP replacement pool information. 29. The method according to any one of Examples 24 to 27, wherein ( Figure 8 Steps 5 and 6) include IP replacement pool information: Send to the V-UPF ( Figure 9 Step 1 or 3) Request, wherein the request is a PFCP association establishment request or a PFCP association modification request; Receive from the V-UPF ( Figure 9 Step 2 or 4) response, the response including the IP replacement pool information. 30. The method according to any one of Examples 24 to 27, wherein ( Figure 8 Steps 5 and 6) include IP replacement pool information: Send to the V-UPF ( Figure 10 Step 1 or 3) Request, wherein the request is a PFCP session establishment request or a PFCP session modification request; Receive from the V-UPF ( Figure 10 Step 2 or 4) response, the response including the IP replacement pool information. 31. A network node adapted to perform the method according to any one of embodiments 24 to 30. 32. A method performed by a User-Plane Function (UPF), the method comprising: Send to Network Memory Function (NRF) Figure 8 , 0A) request, wherein the request is an NF profile registration request or an NF profile update request, and the request includes IP replacement pool information for the UPF (e.g., IP replacement pool information for source IP address replacement (e.g., for HR-SBO PDU sessions of UEs using private IP addresses). 33. The method according to embodiment 32, wherein the IP replacement pool information includes an IP address range. 34. The method according to embodiment 32, wherein the IP replacement pool information includes an IP address range and a port range. 35. A network node adapted to perform the method according to any one of embodiments 32 to 34.

[0046] Any suitable steps, methods, features, functions, or benefits disclosed herein may be performed by one or more functional units or modules of one or more virtual devices. Each virtual device may include multiple such functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessors or microcontrollers and other digital hardware, including digital signal processors (DSPs), application-specific digital logic, etc. The processing circuitry may be configured to execute program code stored in memory, which may include one or more types of memory, such as read-only memory (ROM), random access memory (RAM), buffer memory, flash memory devices, optical storage devices, etc. The program code stored in the memory includes program instructions for executing one or more telecommunications and / or data communication protocols and instructions for executing one or more technologies described herein. In some implementations, according to one or more embodiments of this disclosure, the processing circuitry may be used to cause corresponding functional units to perform corresponding functions.

[0047] While the computing devices described herein (e.g., UE, network node) may include combinations of the hardware components shown, other embodiments may include computing devices with different combinations of components. It will be understood that these computing devices may include any suitable combination of hardware and / or software required to perform the tasks, features, functions, and methods disclosed herein. The determination, calculation, acquisition, or similar operations described herein may be performed by processing circuitry that may process information, for example, by: converting acquired information into other information, comparing the acquired or converted information with information stored in a network node, and / or performing one or more operations based on the acquired or converted information, and making a determination as a result of said processing. Furthermore, although components are depicted as single boxes located within larger boxes or nested within multiple boxes, in practice, a computing device may include multiple different physical components constituting a single illustrated component, and functionality may be partitioned between individual components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of a component may be partitioned between processing circuitry and the communication interface. In another example, non-computationally intensive functions of any such component may be implemented in software or firmware, and computationally intensive functions may be implemented in hardware.

[0048] In certain embodiments, some or all of the functions described herein may be provided by processing circuitry executing instructions stored in memory, which may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functions may be provided by processing circuitry without requiring, for example, hard-wired execution of instructions stored on a separate or separate device-readable storage medium. In any of these particular embodiments, processing circuitry may be configured to perform the described functions regardless of whether instructions stored on a non-transitory computer-readable storage medium are executed. The benefits provided by such functions are not limited to the processing circuitry or other components of the computing device, but are enjoyed by the computing device as a whole and / or generally by the end user and wireless network.

[0049] While the processes in the accompanying drawings may illustrate a particular order of operations performed by certain embodiments of this disclosure, it should be understood that such order is exemplary (e.g., alternative embodiments may perform operations in a different order, combine certain operations, overlap certain operations, etc.).

[0050] Those skilled in the art will recognize improvements and modifications to the embodiments of this disclosure. All such improvements and modifications are considered to be within the scope of the concepts disclosed herein.

Claims

1. A method performed by the Visiting Session Management Function (V-SMF) in a Visiting Public Land Mobile Network (PLMN) for Home Routing (HR) Session Offloading (SBO) of Protocol Data Unit (PDU) sessions of a User Equipment (UE) using a Private Internet Protocol (IP) address, the method comprising: Obtain (Figure 1, steps 5 and 6; Figure 2, steps 1 and 2 or steps 3 and 4; Figure 3, steps 1 and 2 or steps 3 and 4; Figure 5, steps 1 and 2; Figure 6, steps 1 and 2) tunnel information for establishing a tunnel between the Visiting User Plane Function V-UPF and the Visiting Edge Application Server Discovery Function V-EASDF (e.g., for the HR-SBO of the PDU session of the UE using the private IP address); as well as Based on the obtained tunnel information, perform one or more operations (Figure 6, step 1 or step 3; Figure 7, step 1 and / or step 2), which involve establishing a tunnel between the V-UPF and the V-EASDF (e.g., HR-SBO for the PDU session of the UE using the private IP address).

2. The method according to claim 1, wherein, The tunnel information includes the range of IP addresses used to establish a tunnel between the V-UPF and the V-EASDF.

3. The method according to claim 1, wherein, The tunnel information includes the IP address range and port range used to establish a tunnel between the V-UP and the V-EASDF.

4. The method according to any one of claims 1 to 3, wherein, Obtaining the tunnel information (Figure 1, steps 5 and 6) includes: Send a discovery request (Figure 1, step 5) to the Network Repository Function (NRF) in the VPLMN; A discovery response is received from the NRF (Figure 1, step 6), the discovery response including the NF profile of each of one or more candidate V-UPFs, wherein the V-UPF is the selected candidate V-UPF among the one or more candidate V-UPFs, and the NF profile of the V-UPF includes the tunnel information.

5. The method according to any one of claims 1 to 3, wherein, Obtaining the tunnel information (Figure 1, steps 5 and 6) includes: Send a discovery request (Figure 1, step 5) to the Network Repository Function (NRF) in the VPLMN; Receive a discovery response from the NRF (Figure 1, step 6), the discovery response including the NF profile of each candidate V-UPF in one or more candidate V-UPFs and each candidate V-EASDF in one or more candidate V-EASDFs; in: The V-UPF is a selected candidate V-UPF from the one or more candidate V-UPFs; The V-EASDF is a selected candidate V-EASDF from the one or more candidate V-EASDFs; and The obtained tunnel information includes first tunnel information included in the NF profile of the V-UPF and second tunnel information included in the NF profile of the V-EASDF.

6. The method according to any one of claims 1 to 3, wherein, Obtaining the tunnel information (Figure 2, steps 1 and 2 or steps 3 and 4) includes: Send a request (Figure 2, step 1 or 3) to the V-UPF, the request being either a PFCP association establishment request or a PFCP association modification request; Receive a response from the V-UPF (Figure 2, step 2 or 4), the response including the tunnel information.

7. The method according to any one of claims 1 to 3, wherein, Obtaining the tunnel information (Figure 3, steps 1 and 2 or steps 3 and 4) includes: Send a request (Figure 3, step 1 or 3) to the V-UPF, the request being a PFCP session establishment request or a PFCP session modification request; Receive a response from the V-UPF (Figure 3, step 2 or 4), the response including the tunnel information.

8. The method according to any one of claims 1 to 3, wherein, Obtaining the tunnel information (Figure 4, Step 2) includes: During the baseline DNS mode establishment process, the tunnel information is received from the V-EASDF (Figure 4, step 2) (e.g., as part of the baseline DNS mode creation response).

9. The method according to any one of claims 1 to 3, wherein, Obtaining the tunnel information (Figure 5, Step 2) includes: The tunnel information is received from the V-EASDF during the DNS context creation process (Figure 5, step 2) (e.g., as part of the DNS context creation response).

10. The method according to any one of claims 1 to 9 (more specifically, the method according to any one of claims 1 to 4 or 7), wherein, Based on the obtained tunnel information, performing one or more of the operations described in Figure 6, step 1 or step 3 includes: Send a DNS context-related request (Figure 5, step 1 or 3) to the V-EASDF, wherein the DNS context-related request is a DNS context creation request or a DNS context update request, and the DNS context-related request includes tunnel information selected from the obtained tunnel information.

11. The method according to claim 10, wherein, The obtained tunnel information includes a range of IP addresses, and the selected tunnel information includes IP addresses selected from the range of IP addresses.

12. The method according to claim 10, wherein, The obtained tunnel information includes an IP address range and a port number range, and the selected tunnel information includes an IP address selected from the IP address range and a port number selected from the port number range.

13. The method according to any one of claims 1 to 12 (more specifically, the method according to any one of claims 8, 10, 11, or 12), wherein, Performing one or more of the operations described in Figure 6, step 1 or step 3 includes: Send to the V-UPF (Figure 7, step 1) an instruction for the V-UPF to send the associated DNS query to the tunnel established between the V-UPF and the V-EASDF and to extract the associated DNS response from the tunnel (e.g., in a PFCP session modification request).

14. The method according to any one of claims 1 to 13 (more specifically, the method according to any one of claims 8, 10, 11, 12 or 13), wherein, Performing one or more of the operations described in Figure 6, step 1 or step 3 includes: Send to the V-EASDF (Figure 7, step 2) an instruction for the V-EASDF to extract the associated DNS query from the tunnel established between the V-UPF and the V-EASDF and send the associated DNS response via the tunnel (e.g., in a DNS context update).

15. A network node adapted to perform the method according to any one of claims 1 to 14.

16. A method performed by a User-Plane Function (UPF), the method comprising: Send a request (Figure 1, 0A) to the Network Storage Function (NRF), wherein the request is an NF profile registration request or an NF profile update request, and the request includes tunneling information for the UPF (e.g., tunneling information for establishing a tunnel between the UPF and EASDF (e.g., for an HR-SBO PDU session of a UE using a private IP address)).

17. The method according to claim 16, wherein, The tunnel information includes the range of IP addresses used to establish a tunnel (e.g., a tunnel between the UPF and EASDF).

18. The method according to claim 16, wherein, The tunnel information includes the IP address range and port range used to establish the tunnel (e.g., the tunnel between the UPF and EASDF).

19. A network node adapted to perform the method according to any one of claims 15 to 18.

20. A method performed by the Edge Application Server Discovery Function (EASDF), the method comprising: A request (Figure 1, OC) is sent to the Network Storage Function (NRF), wherein the request is an NF profile registration request or an NF profile update request, and the request includes tunneling information for the EASDF (e.g., tunneling information for establishing a tunnel between the EASDF and the UPF (e.g., for an HR-SBO PDU session of a UE using a private IP address)).

21. The method according to claim 16, wherein, The tunnel information includes the range of IP addresses used to establish a tunnel (e.g., a tunnel between the EASDF and the UPF).

22. The method according to claim 16, wherein, The tunnel information includes the IP address range and port range used to establish the tunnel (e.g., the tunnel between the EASDF and the UPF).

23. A network node adapted to perform the method according to any one of claims 20 to 22.

24. A method performed by a Visiting Session Management Function (V-SMF) in a Visiting Public Land Mobile Network (PLMN) for Home Routing (HR) Session Offloading (SBO) of Protocol Data Unit (PDU) sessions of a User Equipment (UE) using a Private Internet Protocol (IP) address, the method comprising: Obtain (Figure 8, steps 5 and 6) IP replacement pool information for uplink services of the HR-SBO PDU session, and replace the source IP address of the UE's HR-SBO PDU session with a mapped (e.g., N6) IP address, where the source IP address is a private UE IP address.

25. The method of claim 24, further comprising: Based on the obtained IP replacement pool, one or more operations are performed, the one or more operations involving: replacing the source IP address of the HR-SBO PDU session of the UE with a mapped (e.g., N6) IP address (selected from the IP replacement pool) for uplink services of the HR-SBO PDU session, the source IP address being the private UE IP address; and mapping the mapped IP address back to the private UE IP address for downlink services of the HR-SBO PDU session.

26. The method according to claim 24 or 25, wherein, The IP replacement pool information includes an IP address range.

27. The method according to claim 24 or 25, wherein, The IP replacement pool information includes IP address range and port range.

28. The method according to any one of claims 24 to 27, wherein, The IP replacement pool information obtained (Figure 8, steps 5 and 6) includes: Send a discovery request (Figure 8, step 5) to the Network Repository Function (NRF) in the VPLMN; A discovery response is received from the NRF (Figure 8, step 6), the discovery response including the NF profile of each of one or more candidate V-UPFs, wherein the V-UPF is the selected candidate V-UPF among the one or more candidate V-UPFs, and the NF profile of the V-UPF includes the IP replacement pool information.

29. The method according to any one of claims 24 to 27, wherein, The IP replacement pool information obtained (Figure 8, steps 5 and 6) includes: Send a request (Figure 9, step 1 or 3) to the V-UPF, the request being either a PFCP association establishment request or a PFCP association modification request; Receive a response from the V-UPF (Figure 9, step 2 or 4), the response including the IP replacement pool information.

30. The method according to any one of claims 24 to 27, wherein, The IP replacement pool information obtained (Figure 8, steps 5 and 6) includes: Send a request (Figure 10, step 1 or 3) to the V-UPF, the request being a PFCP session establishment request or a PFCP session modification request; Receive a response from the V-UPF (Figure 10, step 2 or 4), the response including the IP replacement pool information.

31. A network node adapted to perform the method according to any one of claims 24 to 30.

32. A method performed by a User-Plane Function (UPF), the method comprising: Send a request (Figure 8, 0A) to the Network Storage Function (NRF), wherein the request is an NF profile registration request or an NF profile update request, and the request includes IP replacement pool information for the UPF (e.g., IP replacement pool information for source IP address replacement (e.g., for HR-SBO PDU sessions of UEs using private IP addresses)).

33. The method according to claim 32, wherein, The IP replacement pool information includes an IP address range.

34. The method according to claim 32, wherein, The IP replacement pool information includes IP address range and port range.

35. A network node adapted to perform the method according to any one of claims 32 to 34.

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