Conditional handover

Abstract

Examples of the present disclosure relate to indirect data forwarding during conditional handover. In examples of the present disclosure, a target secondary node receives a secondary node addition request from a target master node. The target secondary node determines whether the target master node is to be used for data forwarding, and sends an acknowledgement of the secondary node addition request. The acknowledgement includes data forwarding information and identifies whether the target master node is to be used for data forwarding.

Description

Technical Field

[0001] The examples disclosed herein involve condition switching. Some examples involve indirect data forwarding during condition switching. Background Technology

[0002] Conditional handover (CHO) is a handover performed by a user equipment (UE) when one or more handover execution conditions are met. A CHO can be performed by a UE configured with dual connectivity. In such an example, the source primary node (MN) (controlling the primary cell (PCell)) sends a handover request to the target MN (controlling the target PCell). In addition to preparing a candidate PCell, the target MN also selects a secondary node (controlling the target primary / secondary cell (PSCell)) and prepares this secondary node as part of the CHO preparation. When the CHO execution conditions are met, the UE performs or initiates an access procedure to the target PCell and PSCell. Summary of the Invention

[0003] Based on various, but not necessarily all, examples of this disclosure, a target secondary node is provided, including: At least one processor; And at least one memory storing instructions that, when executed by at least one processor, cause the target secondary node to execute at least the following: Receive slave node addition requests from the target master node; Determine whether the target master node will be used for data forwarding; Send an acknowledgment of the request to add the secondary node, the acknowledgment including data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0004] Data forwarding information may include tunnel endpoint identifier (TEID) details.

[0005] Determining whether a target master node will be used for data forwarding may include determining whether data forwarding information has previously been sent to the target master node or another target master node.

[0006] The processor and at least one memory can be arranged to enable the target secondary node to execute: It has been determined that the data forwarding information has not yet been sent to the target master node; and Based on the premise that the data forwarding information has not yet been sent to the target master node, the confirmation includes an indication that the target master node will be used for data forwarding.

[0007] The processor and at least one memory can be arranged to enable the target secondary node to execute: It has been confirmed that the data forwarding information has been sent to another target master node; and Based on the confirmation that the data forwarding information has been sent to another target master node, an acknowledgment is sent, but this acknowledgment does not indicate that the target master node will be used for data forwarding.

[0008] The processor and at least one memory can be arranged to enable the target secondary node to execute: Receive a release request from the target master node used for data forwarding; and Based on the release request, a modification request is sent to the target master node that is not used for data forwarding, wherein the modification request includes an indication that the target master node will be used for data forwarding.

[0009] Based on various, but not necessarily all, examples of this disclosure, a method may be provided, including: Receive slave node addition requests from the target master node; Determine whether the target master node will be used for data forwarding; Send an acknowledgment of the request to add the secondary node, the acknowledgment including data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0010] According to various, but not necessarily all, examples of this disclosure, a computer program may be provided that includes instructions that, when executed by a target secondary node, cause the target secondary node to perform at least the following: Receive slave node addition requests from the target master node; Determine whether the target master node will be used for data forwarding; Send an acknowledgment of the request to add the secondary node, the acknowledgment including data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0011] Based on various, but not necessarily all, examples of this disclosure, a target master node may be provided, including: At least one processor; And at least one memory storing instructions that, when executed by at least one processor, cause the target master node to execute at least the following: Send a request to add a secondary node to the target secondary node; Receive confirmation of the request to add a secondary node, wherein the confirmation includes data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0012] Data forwarding information may include tunnel endpoint identification details.

[0013] The confirmation may include an indication that the target master node will be used for data forwarding; and wherein the processor and at least one memory are arranged to enable the target master node to perform: Data forwarding is performed based on the instructions included in the confirmation.

[0014] A secondary node addition request can be sent after a switch request is received from the source primary node.

[0015] The processor and at least one memory can be configured to cause the target master node to perform: sending a switch request confirmation to the source master node, wherein the switch request confirmation indicates whether the target master node will be used for data forwarding.

[0016] The processor and at least one memory can be arranged to enable the target master node to perform: when the target master node is not used for data forwarding, receive a modification request from the target slave node, wherein the modification request includes an indication that the target master node will be used for data forwarding.

[0017] The processor and at least one memory can be arranged to cause the target master node to perform: sending an instruction to the source master node via a new data forwarding path that will be used for data forwarding by the target master node.

[0018] Based on various, but not necessarily all, examples of this disclosure, a method may be provided, including: Send a request to add a secondary node to the target secondary node; Receive confirmation of the request to add a secondary node, wherein the confirmation includes data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0019] According to various, but not necessarily all, examples of this disclosure, a computer program may be provided that includes instructions that, when executed by a target secondary node, cause the target secondary node to perform at least the following: Send a request to add a secondary node to the target secondary node; Receive confirmation of the request to add a secondary node, wherein the confirmation includes data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0020] Based on various, but not necessarily all, examples of this disclosure, a source master node may be provided, including: At least one processor; And at least one memory storing instructions that, when executed by at least one processor, cause the source master node to execute at least the following: Send switchover requests to multiple target master nodes; The switch request confirmation is received from one of the multiple target master nodes, where the switch request confirmation indicates whether one of the multiple target master nodes will be used for data forwarding.

[0021] The confirmation may include an indication that one of a plurality of target master nodes will be used for data forwarding; and wherein a processor and at least one memory are configured to cause the source master node to execute: Based on the instructions included in the confirmation, data forwarding is performed via the target master node among multiple target master nodes.

[0022] The processor and at least one memory can be arranged to enable the target master node to perform: receiving an instruction for a new data forwarding path from one of a plurality of target master nodes, and changing the data forwarding path to the new data forwarding path.

[0023] Based on various, but not necessarily all, examples of this disclosure, a method may be provided, including: Send switchover requests to multiple target master nodes; The switch request confirmation is received from one of the multiple target master nodes, where the switch request confirmation indicates whether one of the multiple target master nodes will be used for data forwarding.

[0024] According to various, but not necessarily all, examples of this disclosure, a computer program may be provided that includes instructions that, when executed by a source secondary node, cause the source secondary node to perform at least the following: Send switchover requests to multiple target master nodes; The switch request confirmation is received from one of the multiple target master nodes, where the switch request confirmation indicates whether one of the multiple target master nodes will be used for data forwarding.

[0025] Based on various, but not necessarily all, examples of this disclosure, a target secondary node may be provided, including: At least one processor; And at least one memory storing instructions that, when executed by at least one processor, cause the source master node to execute at least the following: Receive slave node addition requests from the target master node; It is determined that the data forwarding information has been previously sent to another target master node, and the data forwarding information includes tunnel endpoint identification details; Based on this determination, an acknowledgment is sent for the request to add the secondary node, without including data forwarding information in the acknowledgment.

[0026] Based on various, but not necessarily all, examples of this disclosure, a method may be provided, including: Receive slave node addition requests from the target master node; It is determined that the data forwarding information has been previously sent to another target master node, and the data forwarding information includes tunnel endpoint identification details; Based on this determination, an acknowledgment is sent for the request to add the secondary node, without including data forwarding information in the acknowledgment.

[0027] According to various, but not necessarily all, examples of this disclosure, a computer program may be provided that includes instructions that, when executed by a target secondary node, cause the target secondary node to perform at least the following: Receive slave node addition requests from the target master node; It is determined that the data forwarding information has been previously sent to another target master node, and the data forwarding information includes tunnel endpoint identification details; Based on this determination, an acknowledgment is sent for the request to add the secondary node, without including data forwarding information in the acknowledgment.

[0028] According to various, but not necessarily all, embodiments, an apparatus is provided, comprising: At least one processor; and At least one memory including computer program code; The at least one memory stores instructions that, when executed by the at least one processor, cause the device to perform at least a portion of one or more methods described herein.

[0029] According to various, but not necessarily all, embodiments, an apparatus is provided that includes components for performing at least a portion of one or more methods described herein. The description of functions and / or actions should also be considered as disclosing any components suitable for performing those functions and / or actions. The functions and / or actions described herein can be performed using any suitable method and in any suitable manner.

[0030] Examples as claimed in the appended claims are provided according to various, but not necessarily all, embodiments.

[0031] While the examples and optional features described above in this disclosure are separate, it should be understood that this disclosure covers providing these examples and optional features in all possible combinations and permutations. It should be understood that various examples of this disclosure may include any or all of the features described with respect to other examples of this disclosure, and vice versa. Furthermore, it should be understood that any one, several, or all of the features in any combination may be implemented, included therein, and / or performed by means of, as needed and appropriately, by means of means of apparatus, method, and / or computer program instructions. The description of the function should also be considered as disclosing any components suitable for performing that function. Attached Figure Description

[0032] Some examples will now be described with reference to the accompanying drawings, in which: Figure 1 An example network is shown; Figure 2 Example methods are shown; Figure 3 Example methods are shown; Figure 4 Example methods are shown; Figure 5 illustrates an example signal flow; Figure 6 Example methods are shown; Figure 7 illustrates an example signal flow; Figure 8 An example switch is shown; Figure 9 An example switch is shown; and Figure 10 An example controller is shown.

[0033] The accompanying drawings are not necessarily drawn to scale. For clarity and simplicity, some features and views in the drawings may be shown schematically or enlarged to scale. For example, the dimensions of some elements in the drawings may be enlarged relative to other elements to aid illustration. Corresponding reference numerals are used in the drawings to indicate corresponding features. For clarity, not all reference numerals may be shown in all drawings.

[0034] definition gNBgNodeB MME Mobility Management Entity MN master node NR New Radio PCell main cell PSCell Primary and Secondary Communities QoE experience quality RAN Radio Access Network SN auxiliary node TEID (Tunnel Endpoint Identifier) UE User Equipment Detailed Implementation Figure 1 An example of a communication network 100 is shown, such as a 5G network, a 6G network, or any other suitable type of network. Network 100 includes multiple nodes 110, 120, and 130 of different types. The nodes 110, 120, and 130 of different types may include terminal nodes 110 and network nodes 120 and 130. Network nodes may include access nodes 120 and core network nodes 130 and / or any other suitable type of device or equipment.

[0035] Access node 120 can be configured to communicate with terminal node 110. Core network node 130 communicates with access node 120. In some examples, core network node 130 communicates with terminal node 110.

[0036] In some examples, core network nodes 130 can communicate with each other. In some examples, one or more access nodes 120 can communicate with each other.

[0037] Network 100 may be a cellular network comprising multiple cells 122. Each cell is served by access node 120. In this example, the interface between terminal node 110 and access node 120 providing cell 122 is radio interface 124.

[0038] Access node 120 may include one or more cellular radio transceivers. Terminal node 110 may include one or more cellular radio transceivers.

[0039] Terminal node 110 may include user equipment (UE) or any other suitable type of device.

[0040] Access node 120 may be a base station. Access node 120 may be any suitable type of base station. Access node 120 may be a network entity responsible for radio transmission to or from terminal node 110 in one or more cells. Access node 120 may be a network element in a radio access network (RAN) or any other suitable type of network.

[0041] Core network node 130 may be part of the core network. Core network node 130 may be configured to manage functions related to connectivity with terminal node 110. For example, core network node 130 may be configured to manage functions such as connectivity, mobility, authentication, authorization, and / or other suitable functions.

[0042] exist Figure 1 In the example, core network node 130 is shown as a single entity. In some examples, core network node 130 may be distributed across multiple entities. For example, core network node 130 may be cloud-based or distributed in any other suitable manner.

[0043] Network 100 can be any suitable type of network, for example, a New Radio (NR) network using gNBs as access nodes. NR is the 3GPP term for 5G technology. In this case, access node 120 may include a gNB configured to provide user plane and control plane protocol termination and / or perform any other suitable functions to terminal node 110. The gNBs interconnect each other via X2 / Xn interface 126. The gNBs are also connected to core network node 130 via N2 interface 128. Other types of networks and interfaces can be used in other examples. Other types of networks may include next-generation mobile and communication networks, such as 6G networks.

[0044] UE 110 or other terminal nodes can perform a conditional handover (CHO) from the first access node 120 to the second access node 120. The CHO is designed to allow UE 110 to initiate a handover autonomously without the serving access node 120 triggering the handover execution. To enable the CHO, UE 110 is configured with a CHO command that includes the target cell configuration and the conditions for performing a handover for one or more target cells. These conditions can be based on, for example, radio measurements of neighboring cells or any other suitable factor.

[0045] A Handover Request (CHO) can be performed by a UE 110 configured with dual connectivity. In such an example, the source primary node (MN) (controlling the primary cell (PCell)) sends a handover request to the target MN (controlling the target PCell). In addition to preparing the candidate PCell, the target MN also selects a secondary node (controlling the target primary / secondary cell (PSCell)) and prepares the secondary node as part of the CHO preparation. When the CHO execution conditions are met, the UE 110 performs access to both the target PCell and the PSCell.

[0046] Multiple secondary nodes can be prepared for handover. In the case of multiple preparations, each target MN can prepare its own target secondary node (SN). A target MN can prepare multiple SNs. Multiple target MNs may choose the same target SN because each target MN will receive the same measurements. The target SN can determine that SN add requests received from different target MNs are related to the same UE 110. The target SN can compare the secondary cell group (SCG) configuration to determine that multiple target MNs have provided the same configuration for the bearer terminating at the SN.

[0047] If a bearer terminates at a SN and there are multiple target MNs that have already selected the same target SN, duplicate data forwarding may occur. In scenarios where multiple target MNs have selected the same target SN, data forwarding from the source MN to the target SN can occur via a first target MN and a second target MN. This data duplication or duplicate data forwarding may cause system overload.

[0048] The examples disclosed herein address these issues and reduce unnecessary data forwarding in such systems.

[0049] Figure 2 Example methods that can be implemented in the examples of this disclosure are shown. Figure 2 The method can be implemented by the target SN or a device such as a controller within the target SN.

[0050] Figure 2 The method includes: at box 200, receiving an SN add request from the target MN.

[0051] At box 202, the method includes determining whether the target MN for which a request has been sent will be used for data forwarding.

[0052] In the examples disclosed herein, a target MN may be used for data forwarding if data forwarding information has not previously been sent to another target MN (or target MN). For example, if the target MN is the first target MN to send an SN add request to a target SN, then data forwarding information has not yet been sent to any target node. Therefore, determining whether a target MN will be used for data forwarding may include determining whether data forwarding information has previously been sent to another target MN (or to a target MN).

[0053] At box 204, the method includes sending an acknowledgment of the request to add the SN. This acknowledgment includes data forwarding information. The acknowledgment identifies whether the target MN will be used for data forwarding.

[0054] In some use cases, the target SN will determine that data forwarding information has not yet been sent to the target MN. In this case, the target MN will be used for data forwarding. Therefore, based on the determination that data forwarding information has not yet been sent to the target MN, the target SN will include an indication in the confirmation that the target MN will be used for data forwarding.

[0055] In some use cases, the target SN will determine that the data forwarding information has been sent to the target MN or to another target MN. In this case, the target MN that has already sent the request will not be used for data forwarding. Therefore, based on the determination that the data forwarding information has been sent to a certain target MN, the target SN will include an indication in the acknowledgment that the target MN will not be used for data forwarding. Another option is to leave the information element reserved for the data forwarding information empty. Yet another option is that the information element reserved for the data forwarding information is not present in the acknowledgment.

[0056] Any suitable means can be used to identify whether the target MN will be used for data forwarding. For example, the acknowledgment may include an information element (IE) to identify whether the target MN will be used for data forwarding. In this case, if the IE is present in the acknowledgment, the target MN will be used for data forwarding. If the IE is not present in the acknowledgment, the target MN will not be used for data forwarding.

[0057] The data forwarding information included in the confirmation includes information that enables data to be forwarded to the target SN. This data forwarding information includes Tunnel Endpoint Identifier (TEID) details or any other suitable data. TEID details can also be referred to as Tunnel Endpoint Identification details.

[0058] In some examples, the methods executed by the target SN may include Figure 2The additional boxes are not shown in the diagram. For example, if the target MN cancels the handover request, the additional boxes of this method can be executed to change the target MN used for data forwarding. For example, the target SN can receive a release request from the target MN used for data forwarding. Based on the release request, the target MN sends a modification request to the target MN not used for data forwarding. This could be a target MN that has previously been indicated as not being used for data forwarding. The modification request includes an indication that the target MN will now be used for data forwarding.

[0059] Figure 3 Another example method that can be implemented in the examples disclosed herein is shown. Figure 3 The method can be implemented by the target MN or a device such as a controller within the target MN. Execution Figure 3 The target MN of the method can be related to the execution Figure 2 The target SN of the method corresponds to the target MN.

[0060] Figure 3 The method involves sending an SN add request to the target SN at box 300. The SN add request can be sent after receiving a switch request from the source MN or after any other suitable triggering event.

[0061] At box 302, the method includes receiving an acknowledgment of a request to add an SN. This acknowledgment includes data forwarding information. The acknowledgment identifies whether the target MN will be used for data forwarding.

[0062] Data forwarding information includes information that enables data to be forwarded to the target SN. Data forwarding information may include TEID details.

[0063] If the received acknowledgment includes an indication that the target MN will be used for data forwarding, then the target MN will use the indication included in the acknowledgment to perform data forwarding.

[0064] Conversely, if the received acknowledgment includes an indication that the target MN will not be used for data forwarding, then the target MN will not perform data forwarding.

[0065] Any suitable means can be used to indicate whether the target MN will be used for data forwarding. In some examples, the acknowledgment may include an Information Element (IE) to identify whether the target MN will be used for data forwarding. In this case, if the IE is present in the acknowledgment, the target MN will be used for data forwarding. If the IE is not present in the acknowledgment, the target MN will not be used for data forwarding.

[0066] In some examples, the method may include Figure 3 Additional boxes not shown in the diagram. For example, the method may include sending a trigger... Figure 3The source MN sends a handover request confirmation. The handover request confirmation can indicate whether the target MN will be used for data forwarding.

[0067] Similarly, in some examples, the target MN to be used for data forwarding can be changed. For example, the target MN to be used for data forwarding can cancel the request. In this case, if the target MN is not used for data forwarding, it can receive a modification request from the target SN. The modification request includes an indication that the target MN will be used for data forwarding. In this case, the target MN can send an indication of a new data forwarding path to the source MN. The data forwarding path can then be used for data forwarding via the target MN.

[0068] Figure 4 Another example method that can be implemented in the examples disclosed herein is shown. Figure 4 The method can be implemented by the source MN or a device such as a controller within the source MN. Execution Figure 4 The source MN of the method can be related to the execution Figure 2 The target SN and execution of the method Figure 3 The target MN of the method corresponds to the source MN.

[0069] The method includes sending a switching request to multiple target MNs at box 400.

[0070] At box 402, the method includes receiving a handover request confirmation from a target MN among a plurality of target MNs. The handover request confirmation identifies whether a target MN among the plurality of target MNs will be used for data forwarding.

[0071] If the handover request confirmation includes an indication that one of the multiple target MNs will be used for data forwarding, the method includes performing data forwarding via the target MN. Data forwarding can be performed based on the indication included in the handover request confirmation. In the example, data forwarding can be performed based on the detection that no indication is present in the handover request confirmation.

[0072] Any suitable means can be used to indicate whether the target MN will be used for data forwarding. In some examples, the handover request acknowledgment may include an Information Element (IE) to identify whether the target MN (the sender of the handover request acknowledgment) will be used for data forwarding. In this case, if the IE is present in the handover request acknowledgment, the target MN will be used for data forwarding. If the IE is not present in the handover request acknowledgment, the target MN (the sender of the handover request acknowledgment) will not be used for data forwarding. The handover request acknowledgment can identify whether the target MN will be used for data forwarding.

[0073] The methods executed by the source MN may also include Figure 4The box is not shown in the image. For example, if the target MN cancels the handover request, the method could include... Figure 4 The additional box is not shown in the diagram. The additional box may include an indication to receive a new data forwarding path from one of the multiple target MNs and to change the data forwarding path to the new data forwarding path.

[0074] Figure 5 illustrates example signal flows that can be used in some examples. In the example in Figure 5, multiple data forwarding paths are provided to the source MN, but only one of these data forwarding paths is designated as the primary data forwarding path. In this example, an IE is added to the acknowledgments (SN Add Request Acknowledgment (Ack) and Handover Request Acknowledgment) and is used to indicate whether the target MN will be used for data forwarding. The presence or absence of an IE in the acknowledgment can be used to distinguish between target MNs that will be used for data forwarding and those that will not.

[0075] Figure 5 also illustrates the signaling available if the primary data forwarding path is released. The example signaling flow in Figure 5 can be used to enable different data paths to be designated as the primary data forwarding path.

[0076] In boxes 500 to 506, the source MN prepares multiple target MNs for the CHO of UE 110. In this case, a first target MN and a second target MN are prepared. In other examples, more than two target MNs may be prepared.

[0077] In box 500, the UE sends a measurement report to the source MN. In box 502, the source MN decides whether to trigger a CHO. This decision can be based on the measurement report.

[0078] After deciding to trigger a CHO, the source MN sends a handover request to multiple target MNs. In box 504, the source MN sends a handover request to the first target MN1, and in box 506, the source MN sends a handover request to the second target MN2.

[0079] When a target MN receives a handover request, it will prepare a target SN for the UE's CHO. Target MNs can prepare a target SN for a CHO independently of other target MNs.

[0080] At box 508, the first target MN1 sends an SN add request to the target SN. At box 510, the target SN determines whether the first target MN1 will be used for data forwarding.

[0081] In this example, to determine whether the first target MN1 will be used for data forwarding, the target SN checks whether the TEID details have already been sent to the first target MN1. In this case, the TEID details have not yet been sent to the first target MN1.

[0082] The target SN will reserve resources for the UE for CHO, and at box 512, the target SN sends an acknowledgment (SN Add Request Acknowledgment) to the first target MN1. This acknowledgment includes the TEID and an IE indicating that the first target MN1 will be used as the primary data forwarding path.

[0083] The first target MN1 receives an acknowledgment from the target SN. At box 514, the first target MN1 sends a handover request acknowledgment to the source MN. The handover request acknowledgment includes an IE indicating that the first target MN1 will be used as the primary data forwarding path.

[0084] The second target MN2 follows a similar process to prepare the target SN for the UE's CHO. In this case, the second target MN2 can prepare the same target SN as the target SN prepared by the first target MN1. This situation may occur during the CHO because the corresponding target MNs (the first target MN1 and the second target MN2) receive the same measurement results from the UE.

[0085] At box 516, the second target MN2 sends an SN add request to the target SN. At box 518, the target SN determines whether the second target MN2 will be used for data forwarding.

[0086] In this example, to determine whether the second target MN2 will be used for data forwarding, the target SN checks whether TEID details have already been sent to a target MN. In this case, the TEID details have already been sent to the first target MN1.

[0087] The target SN will determine that resources for CHO have been reserved for the UE. In this case, resources are reserved at the first target MN1. At box 520, the target SN sends an acknowledgment to the second target MN2. The acknowledgment includes the TEID, but does not include the IE indicating that the second target MN2 will be used as the primary data forwarding path. The absence of the IE in the acknowledgment indicates that the second target MN2 will not be used as the primary data forwarding path.

[0088] The second target MN2 receives an acknowledgment from the target SN. At box 522, the second target MN2 sends a handover request acknowledgment to the source MN. The handover request acknowledgment does not include an IE indicating that the second target MN2 will be used as the primary data forwarding path. The acknowledgment does not contain an IE indicating that the second target MN2 will not be used as the primary data forwarding path. Therefore, this notifies the source MN that the UE context exists and reserves resources for the target SN and target MN1.

[0089] At box 524, the source MN sends an RRC reconfiguration message to the UE. The RRC reconfiguration message may include a CHO command.

[0090] In box 526, the UE evaluates the CHO conditions. If one of the CHO conditions is met for the prepared target cell, the UE can apply the corresponding CHO configuration and perform a handover. In box 528, user data is transmitted between the UE and the source MN.

[0091] At box 530, early data forwarding is performed via the first target MN1. Data forwarding is not performed via the second target MN2. Data forwarding is performed according to the instructions provided in the confirmation.

[0092] In the example in Figure 5, an overload scenario or some other similar scenario is detected in the first target MN1, which causes the first target MN1 to decide to cancel CHO.

[0093] At box 532, the first target MN1 sends a CHO switch cancellation message to the source MN, and at box 534, the first target MN1 also sends an SN release request to the target SN.

[0094] The target SN can determine that the target MN1, which has been designated for data forwarding, has cancelled the CHO. Therefore, the primary data forwarding path is no longer used, and the target SN must now determine another data forwarding path. The target MN used to replace the cancelled data forwarding path can be selected based on channel conditions, the order in which the target SN has received requests, or any other suitable factor.

[0095] At box 536, the target SN sends a modification request to the target MN that will replace the first target MN1 as the primary data forwarding path. In this example, there is only one replacement target MN, so the modification request is sent to the second target MN2. At box 538, the second target MN2 sends an acknowledgment of the modification request.

[0096] At box 540, the second target MN2 sends an Xn-U address indication to the source MN. This may include an IE indicating that the second target MN2 will now be used for data forwarding. This is used by the source MN to update the data forwarding TEID details. At box 542, early data forwarding is performed via the second target MN2.

[0097] At box 544, the UE determines that the CHO conditions (or multiple conditions) are met for the prepared cell and performs a handover. At box 546, the UE sends a PRACH preamble to the second target MN2, and at box 548, the second target MN2 sends a RACH response to the UE. At box 550, the UE sends an RRC reconfiguration complete message to the second target MN2. At box 552, the source MN stops transmitting to the UE and begins data forwarding. At box 554, the source MN sends an SN state transition message to the second target MN2. At box 556, data forwarding is performed via the second target MN2. At box 558, a path handover from the source MN to the target MN is performed.

[0098] Figure 6 Another example method that can be implemented in the examples disclosed herein is shown. Figure 6 The method can be implemented by the target SN or a device such as a controller within the target SN.

[0099] Figure 6 The method includes: at box 600, receiving an SN add request from the target MN.

[0100] At box 602, the method includes determining whether data forwarding information has previously been sent to another target MN. The data forwarding information includes TEID details.

[0101] At box 604, the method includes sending an acknowledgment of the request to add the secondary node based on the determination, without including data forwarding information in the acknowledgment. If the target MN will be used for data forwarding, the data forwarding information is included in the acknowledgment; otherwise, if the target MN will not be used for data forwarding, the data forwarding information is not included in the acknowledgment.

[0102] Figure 7 illustrates what can be achieved. Figure 6 The example signal flow of the method is shown in Figure 7. In the example, multiple data forwarding paths are provided to the source MN, but only one of these data forwarding paths is indicated as the primary data forwarding path. In this example, an IE is added to the acknowledgment and used to indicate whether the target MN will be used for data forwarding. The presence or absence of an IE in the acknowledgment can be used to distinguish between target MNs that will be used for data forwarding and target MNs that will not be used for data forwarding.

[0103] Figure 7 also illustrates the signaling available if the primary data forwarding path is released. The example signaling flow in Figure 7 can be used to enable different data paths to be designated as the primary data forwarding path.

[0104] In boxes 700 to 706, the source MN prepares multiple target MNs for the CHO of UE 110. In this case, a first target MN and a second target MN are prepared. In other examples, more than two target MNs may be prepared.

[0105] In box 700, the UE sends a measurement report to the source MN. In box 702, the source MN decides whether to execute a CHO. This decision can be based on the measurement report.

[0106] After deciding to execute the CHO, the source MN sends a handover request to multiple target MNs. In box 704, the source MN sends a handover request to the first target MN1, and in box 706, the source MN sends a handover request to the second target MN2.

[0107] When a target MN receives a handover request, it will prepare a target SN for the UE's CHO. Target MNs can prepare a target SN for a CHO independently of other target MNs.

[0108] At box 708, the first target MN1 sends an SN add request to the target SN. At box 510, the target SN determines whether the first target MN1 will be used for data forwarding.

[0109] In this example, to determine whether the first target MN1 will be used for data forwarding, the target SN checks whether the TEID details have been previously sent to the first target MN1. In this case, the TEID details have not yet been sent to the first target MN1.

[0110] The target SN will reserve resources for the UE for CHO, and at box 712, the target SN sends an acknowledgment to the first target MN1. The acknowledgment includes TEID details. The presence of TEID details in the acknowledgment indicates that the first target MN1 will be used as the primary data forwarding path.

[0111] The first target MN1 receives an acknowledgment from the target SN. At box 714, the first target MN1 sends a handover request acknowledgment to the source MN. The handover request acknowledgment includes an IE indicating that the first target MN1 will be used as the primary data forwarding path.

[0112] The second target MN2 follows a similar process to prepare the target SN for the UE's CHO. In this case, the second target MN2 can prepare the same target SN as the first target MN1. This situation may occur during the CHO because the corresponding target MN receives the same measurement results from the UE.

[0113] At box 716, the second target MN2 sends an SN add request to the target SN. At box 718, the target SN determines whether the second target MN2 will be used for data forwarding.

[0114] In this example, to determine whether the second target MN2 will be used for data forwarding, the target SN checks whether TEID details have already been sent to a target MN. In this case, the TEID details have already been sent to the first target MN1.

[0115] The target SN will determine that resources for CHO have been reserved for the UE. In this case, resources are reserved at the first target MN1. At box 720, the target SN sends an acknowledgment to the second target MN2. The acknowledgment does not include TEID details. The absence of TEID details in the acknowledgment indicates that the second target MN2 will not be used as the primary data forwarding path.

[0116] The second target MN2 receives an acknowledgment from the target SN. At box 722, the second target MN2 sends a handover request acknowledgment to the source MN. The handover request acknowledgment does not include an IE indicating that the second target MN2 will be used as the primary data forwarding path. The acknowledgment does not contain an IE indicating that the second target MN2 will not be used as the primary data forwarding path. Therefore, this notifies the source MN that the UE context exists and reserves resources for the target SN and target MN1.

[0117] At box 724, the source MN sends an RRC reconfiguration message to the UE. The RRC reconfiguration message may include a CHO command.

[0118] In box 726, the UE evaluates the CHO conditions. If one of the CHO conditions is met for the prepared target cell, the UE can apply the corresponding CHO configuration and perform a handover. In box 728, user data is transmitted between the UE and the source MN.

[0119] At box 730, early data forwarding is performed via the first target MN1. Data forwarding is not performed via the second target MN2. Data forwarding is performed according to the instructions provided in the confirmation.

[0120] In the example in Figure 7, an overload scenario or some other similar scenario is detected in the first target MN1, which causes the first target MN1 to decide to cancel CHO.

[0121] At box 732, the first target MN1 sends a CHO switch cancellation message to the source MN, and at box 734, the first target MN1 also sends an SN release request to the target SN.

[0122] The target SN can determine that the target MN1, which has been designated for data forwarding, has cancelled the CHO. Therefore, the primary data forwarding path is no longer used, and the target SN must now determine another data forwarding path. The target MN used to replace the cancelled data forwarding path can be selected based on channel conditions, the order in which the target SN has received requests, or any other suitable factor.

[0123] At box 736, the target SN sends a modification request to the target MN that will replace the first target MN1 as the primary data forwarding path. In this example, there is only one replacement target MN, so the modification request is sent to the second target MN2. The modification request includes TEID details that can be used for data forwarding.

[0124] At box 738, the second target MN2 sends an acknowledgment of the modification request.

[0125] At box 740, the second target MN2 sends an Xn-U address indication to the source MN. This may include an IE indicating that the second target MN2 will now be used for data forwarding. This is used by the source MN to update the data forwarding TEID details. At box 742, early data forwarding is performed via the second target MN2.

[0126] In box 744, the UE determines that the CHO (Confirmation of Hazard) is satisfied for the prepared cell and performs a handover. In box 746, the UE sends a PRACH preamble to the second target MN2, and in box 748, the second target MN2 sends a RACH response to the UE. In box 750, the UE sends an RRC (Reconfiguration Complete) message to the second target MN2. In box 752, the source MN stops transmitting to the UE and begins data forwarding. In box 754, the source MN sends an SN (Status Transfer) message to the second target MN2. In box 756, data forwarding is performed via the second target MN2. In box 758, a path handover from the source MN to the target MN is performed.

[0127] Figure 8 Example switching scenarios that can be used with the examples in this disclosure are shown. Figure 8 The example uses indirect data forwarding. Figure 8 In the example, the data terminates at the source SN. In the first case 800, the data is forwarded from the source SN 804 to the source MN 806, then to the candidate MN 808, and finally to the target SN 810.

[0128] In the second scenario 802, data is forwarded from source SN 804 to candidate MN 808, and then forwarded to target SN 810.

[0129] Figure 9 Example switching scenarios that can be used with the examples in this disclosure are shown. Figure 9 The example uses indirect data forwarding. Figure 9 In the example, the data terminates at the source MN. In case 900, the data is forwarded from the source MN 806 to the candidate MN 808, and then forwarded to the target SN 810.

[0130] Figure 10 An example controller 1000 is shown. The controller 1000 can be housed within an entity such as a target secondary node, a target primary node, a source primary node, or any other suitable entity. The controller 1000 can be implemented as controller circuitry. The controller 1000 can be implemented solely in hardware, some aspects of it can be implemented solely in software including firmware, or it can be implemented using a combination of hardware and software (including firmware).

[0131] like Figure 10As shown, the controller 1000 can be implemented using instructions that implement hardware functions, for example, by using executable instructions of a computer program 1006 in a general-purpose or special-purpose processor 1002, which can be stored on a computer-readable storage medium (disk, memory, etc.) for execution by such processor 1002.

[0132] Processor 1002 is configured to read from and write to memory 1004. Processor 1002 may also include output interfaces and input interfaces, with data and / or commands output from processor 1002 via the output interfaces and data and / or commands input to processor 1002 via the input interfaces.

[0133] Memory 1004 stores a computer program 1006 comprising computer program instructions (computer program code) that control the operation of the device when loaded into processor 1002. The computer program instructions of computer program 1006 provide logic and routines that enable the device to perform the methods shown in the figures. Processor 1002 can load and execute computer program 1006 by reading from memory 1004.

[0134] Therefore, the controller 1000 includes components for the following operations: Receive 200 requests to add secondary nodes from the target primary node; Determine whether the 202 target master node will be used for data forwarding; Send a 204 confirmation of the secondary node addition request, which includes data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0135] Therefore, the controller 1000 includes components for the following operations: Send a 300 secondary node add request to the target secondary node; Receive acknowledgments for the 302 request to add secondary nodes, including data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0136] Therefore, the controller 1000 includes components for the following operations: Send 400 switchover requests to multiple target master nodes; Receive a 402 handover request confirmation from the target master node among multiple target master nodes, where the handover request confirmation indicates whether the target master node among the multiple target master nodes will be used for data forwarding.

[0137] Therefore, the controller 1000 includes components for the following operations: Receive 600 requests to add secondary nodes from the target primary node; It was determined that the 602 data forwarding information had previously been sent to another target master node, and the data forwarding information included tunnel endpoint identification details; Based on this determination, an acknowledgment is sent for the request to add the secondary node, without including data forwarding information in the acknowledgment.

[0138] The computer program 1006 can reach the device via any suitable delivery mechanism 1008. The delivery mechanism 1008 can be, for example, a machine-readable medium, a computer-readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, a recording medium such as a read-only optical disc (CD-ROM), a digital versatile optical disc (DVD), or a solid-state storage device, or an article of manufacture that includes or tangibly embodies the computer program 1006. The delivery mechanism can be a signal configured to reliably transmit the computer program 1006. The device can propagate or transmit the computer program 1006 as a computer data signal.

[0139] Computer program 1006 may include computer program instructions for causing the target secondary node to perform at least the following operations, or for performing at least the following operations: Receive 200 requests to add secondary nodes from the target primary node; Determine whether the 202 target master node will be used for data forwarding; Send a 204 confirmation of the secondary node addition request, which includes data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0140] Computer program 1006 may include computer program instructions for causing the target master node to perform at least the following operations, or for performing at least the following operations: Send a 300 secondary node add request to the target secondary node; Receive acknowledgments for the 302 request to add secondary nodes, including data forwarding information; and This involves confirming whether the target master node will be used for data forwarding.

[0141] Computer program 1006 may include computer program instructions for causing the source master node to perform at least the following operations, or for performing at least the following operations: Send 400 switchover requests to multiple target master nodes; Receive a 402 handover request confirmation from the target master node among multiple target master nodes, where the handover request confirmation indicates whether the target master node among the multiple target master nodes will be used for data forwarding.

[0142] Computer program 1006 may include computer program instructions for causing the target secondary node to perform at least the following operations, or for performing at least the following operations: Receive 600 requests to add secondary nodes from the target primary node; It was determined that the 602 data forwarding information had previously been sent to another target master node, and the data forwarding information included tunnel endpoint identification details; Based on this determination, an acknowledgment is sent for the request to add the secondary node, without including data forwarding information in the acknowledgment.

[0143] Computer program instructions may be contained in a computer program, a non-transitory computer-readable medium, a computer program product, or a machine-readable medium. In some, but not all, examples, computer program instructions may be distributed across more than one computer program.

[0144] Although memory 1004 is shown as a single component / circuit, it can be implemented as one or more separate components / circuits, some or all of which may be integrated / removable and / or provide permanent / semi-permanent / dynamic / cached storage.

[0145] Although processor 1002 is shown as a single component / circuit, it can be implemented as one or more separate components / circuits, some or all of which may be integrated / removable. Processor 1002 may be a single-core or multi-core processor.

[0146] According to the examples of this disclosure, the device can be provided in an electronic device (e.g., a mobile terminal). However, it should be understood that a mobile terminal is merely one example of an electronic device that will benefit from the implementation examples of this disclosure, and therefore the scope of this disclosure should not be limited to mobile terminals. While the device may be located in a mobile terminal in some implementation examples, other types of electronic devices, such as, but not limited to, mobile communication devices, handheld portable electronic devices, wearable computing devices, portable digital assistants (PDAs), pagers, mobile computers, desktop computers, televisions, gaming devices, laptop computers, cameras, video recorders, GPS devices, and other types of electronic systems, can also readily adopt the examples of this disclosure. Furthermore, the examples of this disclosure can be readily adopted regardless of whether the device is intended to provide mobility.

[0147] The term "includes" in this document has an inclusive rather than exclusive meaning. That is, any reference to X that includes Y means that X may include only one Y or may include multiple Ys. If "includes" is intended to be used in an exclusive sense, it will be clearly stated in the context by referring to "includes only one..." or using "consisting of...".

[0148] In this description, the terms “connection,” “coupling,” and “communication,” and their derivatives, mean operational connection / coupling / communication. It should be understood that any number or combination of intermediate components (including the absence of intermediate components) may exist to provide direct or indirect connection / coupling / communication. Any such intermediate component may include hardware and / or software components.

[0149] As used herein, the term "determine / perform determination" (and its grammatical variations) can include, in particular, calculation, operation, processing, derivation, measurement, investigation, identification, lookup (e.g., searching in a table, database, or other data structure), ascertainment, etc. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), obtaining, etc. Additionally, "determine / perform determination" can include parsing, selecting, picking, establishing, etc.

[0150] Various examples have been referenced in this description. Descriptions of features or functionalities in an example indicate that those features or functionalities exist in that example. The use of the terms "example," "for example," "able," or "may" in the text indicates that, whether explicitly stated or not, these features or functionalities exist at least in the described example, and may, but not necessarily, exist in some or all other examples. Therefore, "example," "for example," "able," or "may" refers to a specific instance within a class of examples. An instance's properties may be properties only of that instance, properties of the class, or properties of a subclass of the class (which includes some, but not all, instances of the class). Therefore, it is implicitly disclosed that features described with reference to one example but not another may be used in that other example as part of a feasible combination where possible, but are not necessarily required to be used in that other example.

[0151] As used herein, “at least one of the following:”, “at least one of…” and similar wording, in a list of two or more elements connected by “and” or “or”, means at least any one element, at least any two or more elements, or at least all elements.

[0152] Although examples have been described with reference to various examples in the preceding paragraphs, it should be understood that modifications may be made to the given examples without departing from the scope of the claims.

[0153] The features described above can be used in combinations other than those explicitly described above.

[0154] Although some features have been described with reference to certain characteristics, these functions can be performed by other features, whether or not they are described.

[0155] A description of a feature (e.g., a device or component of a device) configured to perform a function or for performing a function should also be considered to disclose a method for performing that function. For example, a description of a device configured to perform one or more actions or for performing one or more actions should also be considered to disclose a method for performing the one or more actions with or without the aid of that device.

[0156] Although features have been described with reference to some examples, these features may also exist in other examples, whether or not they are described.

[0157] The terms “a,” “an,” or “the” are used in this document in an inclusive rather than exclusive sense. That is, any reference to X including “a,” “an,” or “the” Y means that X may include only one Y or may include multiple Ys, unless the context clearly indicates the opposite. If “a,” “an,” or “the” is intended to be used in an exclusive sense, it will be clearly stated in the context. In some cases, the use of “at least one” or “one or more” may be used to emphasize an inclusive meaning, but should not be inferred from the absence of these terms that they have any exclusive meaning.

[0158] The presence of a feature (or combination of features) in a claim is a reference to that feature or combination of features itself, as well as to features that achieve substantially the same technical effect (equivalent features). Equivalent features include, for example, features that are variations and achieve substantially the same result in substantially the same manner. Equivalent features include, for example, features that perform substantially the same function in substantially the same manner to achieve substantially the same result.

[0159] In this description, various examples have been mentioned and adjectives or adjective phrases have been used to describe the characteristics of the examples. Such descriptions of characteristics of examples indicate that the characteristic exists exactly as described in some examples, and substantially as described in others.

[0160] The foregoing description illustrates some examples of this disclosure; however, those skilled in the art will recognize possible alternative structures and methodological features that provide equivalent functionality to the specific examples of such structures and features described above, and for the sake of brevity and clarity, have been omitted from the foregoing description. Nevertheless, the foregoing description should be understood to implicitly include references to such alternative structures and methodological features that provide equivalent functionality, unless such alternative structures or methodological features are explicitly excluded in the foregoing description of the examples of this disclosure.

[0161] Although efforts have been made in the foregoing specification to draw attention to those features deemed important, whether or not they are emphasized, the applicant may seek protection by means of any patentable feature or combination of features mentioned above and / or shown in the figures.

Claims

1. A target auxiliary node, comprising: At least one processor; and at least one memory, the at least one memory storing instructions that, when executed by the at least one processor, cause the target secondary node to perform at least the following: Receive slave node addition requests from the target master node; Determine whether the target master node will be used for data forwarding; Send an acknowledgment of the request to add the secondary node, wherein the acknowledgment includes data forwarding information; and The confirmation indicates whether the target master node will be used for data forwarding.

2. The target auxiliary node according to claim 1, wherein the data forwarding information includes tunnel endpoint identifier (TEID) details.

3. The target secondary node according to any one of the preceding claims, wherein determining whether the target primary node will be used for data forwarding includes determining whether data forwarding information has previously been sent to the target primary node or another target primary node.

4. The target secondary node according to claim 3, wherein the processor and at least one memory are arranged to cause the target secondary node to perform: It is determined that the data forwarding information has not yet been sent to the target master node; and Based on the determination that the data forwarding information has not yet been sent to the target master node, the confirmation includes an indication that the target master node will be used for data forwarding.

5. The target secondary node according to claim 3, wherein the processor and at least one memory are arranged to cause the target secondary node to perform: It is determined that the data forwarding information has been sent to the other target master node; and Based on the determination that the data forwarding information has been sent to the other target master node, the confirmation is sent, but the confirmation does not indicate that the target master node will be used for data forwarding.

6. The target secondary node according to any one of the preceding claims, wherein the processor and at least one memory are arranged to cause the target secondary node to perform: Receive a release request from the target master node used for data forwarding; and Based on the release request, a modification request is sent to the target master node that is not used for data forwarding, wherein the modification request includes an indication that the target master node will be used for data forwarding.

7. A method comprising: Receive slave node addition requests from the target master node; Determine whether the target master node will be used for data forwarding; Send an acknowledgment of the request to add the secondary node, wherein the acknowledgment includes data forwarding information; and The confirmation indicates whether the target master node will be used for data forwarding.

8. A computer program comprising instructions that, when executed by a target secondary node, cause the target secondary node to perform at least the following: Receive slave node addition requests from the target master node; Determine whether the target master node will be used for data forwarding; Send an acknowledgment of the request to add the secondary node, wherein the acknowledgment includes data forwarding information; and The confirmation indicates whether the target master node will be used for data forwarding.

9. A target master node, comprising: At least one processor; and at least one memory, the at least one memory storing instructions that, when executed by the at least one processor, cause the target master node to execute at least the following: Send a request to add a secondary node to the target secondary node; Receive confirmation of the request to add the secondary node, wherein the confirmation includes data forwarding information; and The confirmation indicates whether the target master node will be used for data forwarding.

10. The target master node according to claim 8, wherein the data forwarding information includes tunnel endpoint identification details.

11. The target master node according to any one of claims 9 to 10, wherein the confirmation includes an indication that the target master node will be used for data forwarding; and wherein the processor and at least one memory are arranged to cause the target master node to perform: Data forwarding is performed based on the indication included in the confirmation.

12. The target master node according to any one of claims 9 to 11, wherein the secondary node addition request is sent after receiving the switchover request from the source master node.

13. The target master node according to any one of claims 9 to 12, wherein the processor and at least one memory are arranged to cause the target master node to perform: sending a handover request confirmation to the source master node, wherein the handover request confirmation identifies whether the target master node will be used for data forwarding.

14. The target master node according to any one of claims 9 to 13, wherein the processor and at least one memory are arranged to cause the target master node to perform: when the target master node is not used for data forwarding, receiving a modification request from the target slave node, wherein the modification request includes an indication that the target master node will be used for data forwarding.

15. The target master node of claim 14, wherein the processor and at least one memory are arranged to cause the target master node to perform: sending an indication to the source master node of a new data forwarding path via the target master node to be used for data forwarding.

16. A method comprising: Send a request to add a secondary node to the target secondary node; Receive confirmation of the request to add the auxiliary node, wherein the confirmation includes data forwarding information; and The confirmation indicates whether the target master node will be used for data forwarding.

17. A computer program comprising instructions that, when executed by a target secondary node, cause the target secondary node to perform at least the following: Send a request to add a secondary node to the target secondary node; Receive confirmation of the request to add the secondary node, wherein the confirmation includes data forwarding information; and The confirmation indicates whether the target master node will be used for data forwarding.

18. A source master node, comprising: At least one processor; and at least one memory, the at least one memory storing instructions that, when executed by the at least one processor, cause the source master node to execute at least the following: Send switchover requests to multiple target master nodes; Receive a handover request confirmation from one of the plurality of target master nodes, wherein the handover request confirmation indicates whether the target master node among the plurality of target master nodes will be used for data forwarding.

19. The source master node of claim 18, wherein the confirmation includes an indication that one of the plurality of target master nodes will be used for data forwarding; and wherein the processor and at least one memory are arranged to cause the source master node to perform: Based on the indication included in the confirmation, data forwarding is performed via the target master node among the plurality of target master nodes.

20. The source master node according to any one of claims 18 to 19, wherein the processor and at least one memory are arranged to cause the target master node to perform: receiving an instruction for a new data forwarding path from a target master node among the plurality of target master nodes, and changing the data forwarding path to the new data forwarding path.

21. A method comprising: Send switchover requests to multiple target master nodes; Receive a handover request confirmation from one of the plurality of target master nodes, wherein the handover request confirmation indicates whether the target master node among the plurality of target master nodes will be used for data forwarding.

22. A computer program comprising instructions that, when executed by a source secondary node, cause the source secondary node to perform at least the following: Send switchover requests to multiple target master nodes; Receive a handover request confirmation from one of the plurality of target master nodes, wherein the handover request confirmation indicates whether the target master node among the plurality of target master nodes will be used for data forwarding.

23. A target auxiliary node, comprising: At least one processor; and at least one memory, the at least one memory storing instructions that, when executed by the at least one processor, cause the source master node to execute at least the following: Receive slave node addition requests from the target master node; It is determined that data forwarding information has been previously sent to another target master node, wherein the data forwarding information includes tunnel endpoint identification details; Based on the determination, an acknowledgment of the request to add the secondary node is sent, without including the data forwarding information in the acknowledgment.

24. A method comprising: Receive slave node addition requests from the target master node; It is determined that data forwarding information has been previously sent to another target master node, wherein the data forwarding information includes tunnel endpoint identification details; Based on the determination, an acknowledgment of the request to add the secondary node is sent, without including the data forwarding information in the acknowledgment.

25. A computer program comprising instructions that, when executed by a target secondary node, cause the target secondary node to perform at least the following: Receive slave node addition requests from the target master node; It is determined that data forwarding information has been previously sent to another target master node, wherein the data forwarding information includes tunnel endpoint identification details; Based on the determination, an acknowledgment of the request to add the secondary node is sent, without including the data forwarding information in the acknowledgment.

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