WO2022151030A1

WO2022151030A1 - Method and apparatus for automatic configuration of ng control plane interface

Info

Publication number: WO2022151030A1
Application number: PCT/CN2021/071439
Authority: WO
Inventors: Qiong SONG; Xiaoming Li
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2021-01-13
Filing date: 2021-01-13
Publication date: 2022-07-21

Abstract

A method for NG control plane configuration is proposed. The method which may be performed by a first AMF comprises receiving from a NRF a notification message. The method further comprises sending a configuration message comprising TNL information of the second AMF to one or more RAN node. The notification message comprises the TNL, information of a second AMF when the second AMF is added to an AMF set which includes the first AMF; and the configuration message comprises the TNL information of the second AMF. According to the embodiments of the present disclosure, the NG control plane can be configured automatically and be handled more efficiently.

Description

METHOD AND APPARATUS FOR AUTOMATIC CONFIGURATION OF NG CONTROL PLANE INTERFACE

FIELD OF THE INVENTION

The present disclosure generally relates to communication networks, and more specifically, to automatic configuration of NG control plane interface in a communication network.

BACKGROUND

This section introduces aspects that may facilitate a better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.

The 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 23.501 V16.7.0 (2020-12) illustrates the System architecture for the 5G System (5GS) . In this system architecture, N2 is the reference point between Radio Access Network (RAN) and Access and Mobile Management Function (AMF) . TS 23.501 also illustrates the Control Plane Protocol Stacks between the 5G-AN and the 5G Core: N2, wherein the N2 may map to NG Control plane (NG-C) as defined in 3GPP TS 38.413 V16.3.0 (2020-09) . In this protocol stack, the application layer protocol, referred to NG Application Protocol (NG-AP) is on top of the transport layer protocol, referred to Stream Control Transmission Protocol (SCTP) . The SCTP protocol that is built on Internet Protocol (IP) guarantees delivery of signalling messages. SCTP is defined in IETF RFC 4960: "Stream Control Transmission Protocol" .

A new AMF may be added into or removed out from an AMF set for the scalability, in addition, an AMF may optionally provide backup AMF to deal with planned maintenance and/or failure when the associated AMF is unavailable. It is assumed that the backup AMF and the original AMF are in the same AMF set as they have access to the same UE context.

The 5G System should support establishment of association between AMF and 5G-AN node. In the current 5G System, 5G-AN is responsible for initiating the SCTP connectivity and setting up the NG-C association with the AMF when a new AMF is added to a AMF set. However, for the new added AMF, the 5G-AN is not aware the Transport Network Layer (TNL) association information to set the SCTP connectivity with the new added AMF. Therefore, the 5G-AN may need to local configure the new AMF IP end points manually when the new AMFs is added into an AMF set for scalability or planned maintenance.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

In order to establish the SCTP connectivity with the new added AMF, the 5G-AN needs to be aware the TNL association information with the new added AMF. Various embodiments of the present disclosure propose a solution to enable 5G-AN obtain automatically the TNL association information when one or more AMF are added to an AMF set. In this way, it allows the NG-C interface configuration automatically and more efficiently.

According to a first aspect of the present disclosure, there is provided a method performed by a first Access and Mobility Management Function, AMF. The method comprises receiving from a Network Repository Function, NRF a notification message comprising Transport Network Layer, TNL, information of a second AMF when the second AMF is added to a AMF set which includes the first AMF; and the method further comprises sending a configuration message comprising TNL information of the second AMF to one or more Radio Access Network, RAN, node (e.g., a gNodeB, a NG-eNodeB, etc. ) .

In accordance with an exemplary embodiment, the first AMF may have Stream Control Transmission Protocol, SCTP, connectivity with one or more RAN node, and the second AMF may have no SCTP connectivity with the one or more RAN node.

In accordance with an exemplary embodiment, the method may further comprise determining whether send the configuration message to the one or more RAN node based on the received information of the notification message.

In accordance with an exemplary embodiment, the received information may comprise status of the second AMF.

In accordance with an exemplary embodiment, the method may further comprise sending the configuration message when the status indicating the second AMF is undiscoverable and no Track Area Identifier (TAI) list is included in the notification message.

In accordance with an exemplary embodiment, the TNL information may comprise Internet Protocol, IP, address and/or port number.

In accordance with an exemplary embodiment, the IP address and/or port number may be included in TNL association address; and the TNL information may further comprise at least one of TNL association usage, TNL address weight factor, and AMF name.

In accordance with an exemplary embodiment, the method may further comprise subscribing to receiving the notification message from the NRF based on configuration prior to receiving the notification message.

According to a second aspect of the present disclosure, there is provided a method performed by a Radio Access Network, RAN, node (e.g., a gNodeB, a NG-eNodeB, etc. ) . The method comprises receiving from an AMF a configuration message comprising TNL information (e.g., IP address and/or port number, etc. ) of a second AMF. The method further comprises sending a message to the second AMF to initiate the SCTP connectivity based on the TNL information.

In accordance with an exemplary embodiment, the wherein the IP address and/or port number may be included in TNL association address; and the TNL information may further comprise at least one of TNL association usage, TNL address weight factor, and AMF name.

According to a third aspect of the present disclosure, there is provided a method performed by a second AMF. The method comprises sending a registration message comprising TNL information (e.g., IP address and/or port number, etc. ) of the second AMF to register in an NRF when the second AMF is added to an AMF set. The method further comprises receiving a message to initiate a SCTP connectivity from a RAN node (e.g., a gNodeB, a NG-eNodeB, etc. ) .

In accordance with an exemplary embodiment, the registration message may further comprise one of: amfRegionId, amfSetId, Globally Unique AMF Id, GUAMI.

In accordance with an exemplary embodiment, the TAI list may not be included in the registration message.

In accordance with an exemplary embodiment, the registration message may comprise status of the second AMF indicating the second AMF is undiscoverable.

According to a fourth aspect of the present disclosure, there is provided a method performed by an NRF. The method comprises receiving from an AMF a registration message comprising TNL information (e.g., IP address and/or port number, etc. ) to register in the NRF when the second AMF is added to an AMF set. The method further comprises sending to a first AMF a notification message comprising TNL information of the second AMF when the AMF set includes the first AMF.

In accordance with an exemplary embodiment, the registration message may comprise one of: amfRegionId, amfSetId, GUAMI.

In accordance with an exemplary embodiment, the method may further comprise receiving a message for subscribing to the notification message from the first AMF prior to sending the notification message; and the NRF sending the notification message based on the subscription.

According to a fifth aspect of the present disclosure, there is provided an apparatus which may be implemented as an AMF. The apparatus may comprise one or more processors and one or more memories comprising computer program codes. The one or more memories and the computer program codes may be configured to, with the one or more processors, cause the apparatus at least to perform any step of the method according to the first aspect of the present disclosure.

According to a sixth aspect of the present disclosure, there is provided an apparatus which may be implemented as a RAN node. The apparatus may comprise one or more processors and one or more memories comprising computer program codes. The one or more memories and the computer program codes may be configured to, with the one or more processors, cause the apparatus at least to perform any step of the method according to the second aspect of the present disclosure.

According to a seventh aspect of the present disclosure, there is provided an apparatus which may be implemented as an AMF. The apparatus may comprise one or more processors and one or more memories comprising computer program codes. The one or more memories and the computer program codes may be configured to, with the one or more processors, cause the apparatus at least to perform any step of the method according to the third aspect of the present disclosure.

According to an eighth aspect of the present disclosure, there is provided an apparatus which may be implemented as an NRF. The apparatus may comprise one or more processors and one or more memories comprising computer program codes. The one or more memories and the computer program codes may be configured to, with the one or more processors, cause the apparatus at least to perform any step of the method according to the fourth aspect of the present disclosure.

According to a ninth aspect of the present disclosure, there is provided a computer-readable medium having computer program codes embodied thereon which, when executed on a computer, cause the computer to perform any step of the method according to any one of the first to fourth aspect of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure itself, the preferable mode of use and further objectives are best understood by reference to the following detailed description of the embodiments when read in conjunction with the accompanying drawings, in which:

Fig. 1 is a diagram illustrating an exemplary example of 5GS architecture;

Fig. 2 is a diagram illustrating protocol stack of N2 interface of 5GS;

Fig. 3 is a diagram illustrating an exemplary procedure for configuring NG control plane automatically;

Fig. 4 is a flowchart illustrating a method according to some embodiments of the present disclosure;

Fig. 5 is a flowchart illustrating another method according to some embodiments of the present disclosure;

Fig. 6 is a flowchart illustrating yet another method according to some embodiments of the present disclosure;

Fig. 7 is a flowchart illustrating a further method according to some embodiments of the present disclosure;

Fig. 8 is a block diagram illustrating an apparatus according to some embodiments of the present disclosure;

Fig. 9 is a block diagram illustrating another apparatus according to some embodiments of the present disclosure;

Fig. 10 is a block diagram illustrating yet another apparatus according to some embodiments of the present disclosure;

Fig. 11 is a block diagram illustrating yet another apparatus according to some embodiments of the present disclosure; and

Fig. 12 is a block diagram illustrating a further apparatus according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The embodiments of the present disclosure are described in detail with reference to the accompanying drawings. It should be understood that these embodiments are discussed only for the purpose of enabling those skilled persons in the art to better understand and thus implement the present disclosure, rather than suggesting any limitations on the scope of the present disclosure. Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present disclosure should be or are in any single embodiment of the disclosure. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Furthermore, the described features, advantages, and characteristics of the disclosure may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the disclosure may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the disclosure.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as new radio (NR) , long term evolution (LTE) , LTE-Advanced, wideband code division multiple access (WCDMA) , high-speed packet access (HSPA) , and so on. Furthermore, the communications between a terminal device and a network node in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , 4G, 4.5G, 5G communication protocols, and/or any other protocols either currently known or to be developed in the future. A network function/network node/network entity can be implemented either as a network element on a dedicated hardware, as a software instance running on a dedicated hardware, or as a virtualized function instantiated on an appropriate platform, e.g. on a cloud infrastructure.

As used herein, the terms “first” , “second” and so forth refer to different elements. The singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” as used herein, specify the presence of stated features, elements, and/or components and the like, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. The term “based on” is to be read as “based at least in part on” . The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment” . The term “another embodiment” is to be read as “at least one other embodiment” . Other definitions, explicit and implicit, may be included below.

The 5G System architecture is defined to support data connectivity and services enabling deployments to use techniques such as e.g. Network Function Virtualization and Software Defined Networking. Fig. 1 depicts one example of the reference 5G architecture. The 5G System architecture consists of the following network functions (NF) : Authentication Server Function (AUSF) , Access and Mobility Management Function (AMF) , Data Network (DN) , e.g. operator services, Internet access or 3rd party services, Network Exposure Function (NEF) , Network Repository Function (NRF) , Network Slice Specific Authentication and Authorization Function (NSSAAF) , Network Slice Selection Function (NSSF) , Policy Control Function (PCF) , Session Management Function (SMF) , Unified Data Management (UDM) , User Plane Function (UPF) , Application Function (AF) , User Equipment (UE) , (Radio) Access Network ( (R) AN) and Service Communication Proxy (SCP) . The 5G System Architecture contains the following service-based interfaces: Namf: Service-based interface exhibited by AMF, Nsmf: Service-based interface exhibited by SMF, Nnef: Service-based interface exhibited by NEF, Npcf: Service-based interface exhibited by PCF, Nudm: Service-based interface exhibited by UDM, Naf: Service-based interface exhibited by AF, Nnrf: Service-based interface exhibited by NRF, Nnssaaf: Service-based interface exhibited by NSSAAF, Nnssf: Service-based interface exhibited by NSSF and Nausf: Service-based interface exhibited by AUSF. The 5G System Architecture contains the following reference points: N1: Reference point between the UE and the AMF, N2: Reference point between the (R) AN and the AMF, N3: Reference point between the (R) AN and the UPF, N4: Reference point between the SMF and the UPF, N6: Reference point between the UPF and a Data Network and N9: Reference point between two UPFs. The 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 23.501 V16.7.0 (2020-12) provides the detailed description for this architecture and N2 maps to NG-C as defined in 3GPP TS 38.413 V16.3.0 (2020-09) .

Fig. 2 depicts one overall protocol stacks under N2 interface, between the (R) AN and the AMF. The N2 interface may map to an NG control plane (NG-C) interface, which may be a logical interface between an AMF and RAN node. The NG-C protocol stack may include a transport network layer that is built on Internet Protocol (IP) transport. For the reliable transport of signaling messages, a stream control transmission protocol (SCTP) layer is added on top of the IP layer to guarantee delivery of signalling messages between AMF and 5G-AN node. The application layer signaling protocol on top of the SCTP layer is referred to as NG Application Protocol (NG-AP) .

The 5G System should support establishment of association between AMF and 5G-AN node. A new AMF may be added to an AMF set and association between AMF and Globally Unique AMF ID (GUAMI) can be created and/or updated as follows: AMF shall be able to dynamically update the Network Repository Function (NRF) with the new or updated GUAMI (s) to provide mapping between GUAMI (s) and AMF information. In addition, to deal with planned maintenance and/or failure, an AMF may optionally provide backup AMF information, i.e. it acts as a backup AMF if the indicated GUAMI associated AMF is unavailable. It is assumed that the backup AMF and the original AMF are in the same AMF set as they have access to the same UE context. Based on that information one GUAMI is associated with an AMF, optionally with a backup AMF used for planned removal and/or failure. Upon successful update, the NRF may provide the new and/or updated GUAMI (s) as AMF discovery results to the requester. The requester may be other Control Plane network function (s) . The new AMF provides its GUAMI to 5G-AN and then the 5G-AN stores this association. If the association between the same GUAMI and another AMF exists in the 5G-AN (e.g. due to AMF planned removal) , the previously stored AMF is replaced by the new AMF for the corresponding GUAMI association.

For establishment of association between AMF and 5G-AN node, it may be needed that an initial remote IP end point to be used for SCTP initialization be provided to the NG-RAN node for each AMF the NG-RAN node is supposed to connect to. Then the NG-RAN establishes the first SCTP using the IP address. Currently, the IP address may be configured manually, and it may be inefficient.

In order to improve the NG-C configuration efficiency, the present disclosure according to some exemplary embodiments proposes a solution to enable 5G-AN obtain automatically the IP address. In this way, it allows the NG-C interface configuration automatically and more efficiently.

Fig. 3 is a diagram illustrating an exemplary procedure for configuring NG control plane automatically according to some embodiments of the present disclosure. This exemplary procedure may be performed to enable a NG-AN node to obtain the TNL information of a new added AMF automatically.

As shown in Fig. 3, when a new AMF is added to an AMF set, wherein the AMF set may include an AMF, the new AMF send 301 Network Function (NF) registration to NRF with NF profile. The NF registration may comprise a NF status indicating the new AMF is "UNDISCOVERABLE" . The NF registration may include amfRegionId, amfSetId, guami. The NF registration may not include TAI list information since no 5G-AN node (e.g., a gNodeB, a NG-eNodeB, etc. ) connect with the new AMF. The NF registration may include AMF TNL Association indicating TNL information of the new AMF wherein the TNL information may comprise Internet Protocol, IP, address and/or port number.

According to an exemplary embodiment, the NF registration may comprise Amfinfo; and an exemplary definition of AmfInfo is shown in Table 1 as below.

Table 1

As shown in table 1, the AMFinfo may comprise AMF TNL Association List, wherein the AMF TNL Association indicates the TNL information. An exemplary definition of AMF TNL Association is shown in Table 2; an exemplary definition of TNL Association Usage is shown in Table 3; and an exemplary definition of TNLAddressWeightFactor is shown in Table 4, as below. After the registration, the NRF sends 302 Created (NF Profile) to the new AMF.

Table 2

Table 3

Table 4

The NRF sends 303 NFStatusNotify with NF Profile to the AMF, wherein the NFStatusNotify with NF profile may include the AMF TNL Association indicating TNL information of the new AMF wherein the TNL information may comprise Internet Protocol, IP, address and/or port number. The NFStatusNotify may comprise a NF status indicating the new AMF is "UNDISCOVERABLE" . The NF registration may include amfRegionId, amfSetId, guami. The NF registration may not include TAI list information since no 5G-AN node (e.g., a gNodeB, a NG-eNodeB, etc. ) connect with the new AMF. According to an exemplary embodiment, the NF NFStatusNotify may comprise Amfinfo. An exemplary definition of AmfInfo is shown in Table 1; and the exemplary definition of AMF TNL Association, TNL Association Usage and TNLAddressWeightFactor are shown in Table 2, 3, 4 respectively as above.

In accordance with some exemplary embodiments, prior to the receiving the 303 NFStatusNotify with AMF TNL Association indicating TNL information of the new AMF, the AMF may subscribe to changes on the status of other AMF Instances registered in NRF based on the AMF local configuration. It may be only one AMF which activate the automatic configuration of NG-C interface functionality in the AMF set is necessary to be notified of the changes on the status of new AMF instance.

In accordance with some exemplary embodiments, if the AMF outage, one option is operator aware of the AMF outage then activates the automatic NGAP configuration functionality in another AMF. Another option is when geographical redundancy is activated, there is an private message between each AMFs to monitor the AMF status in the AMF set, there could be private IEs to indicate another AMF about the functionality, then another AMF can activate the functionality when detect the AMF outage. e.g. AMF which defined as “master” activate the automatic NGAP configuration functionality (through configuration) and indicate other AMFs in the private message, another AMF which is defined as “standby” can activate the functionality when detect the “master” AMF down.

When the AMF receives the 303 NFStatusNotify with NF profile which comprises the AMF TNL Association indicating TNL information of the new AMF, the AMF may determine whether send configuration message to the one or more RAN node based on the received information. If the received NF profile which includes the new AMF name, AmfInfo, and the new AMF status is “undiscoverable” , and no TAI list, the AMF may be aware that the new AMF TNL Association need to be broadcasted to one or more RAN nodes with which the AMF has transport layer (e.g., SCTP) connection. Then the AMF sends 304 Configuration Update with TNL Association of the New AMF to the one or more RAN nodes wherein the TNL Association indicates the TNL information of the new AMF.

According to an exemplary embodiment, the Configuration Update may comprise a list of New AMF TNL Association Item; and an exemplary definition of New AMF TNL Association Item is shown in Table 5 as below. The RAN node acknowledges via sending 305 AMF Configuration Update Acknowledge to the AMF.

Table 5

The New AMF TNL Association Item may comprise New AMF TNL Association Address and an exemplary definition of New AMF TNL Association Address is shown in Table 6 as below.

Table 6

After the RAN node receives the 304 Configuration Update with TNL Association of the new AMF, based on the received TNL information, in step 306, initiates the SCTP connectivity with the new AMF and triggers the NG setup procedure to the new AMF. The new AMF sends 307 N2 setup Response to the RNC node after receives 306 Configuration Update; then sends 308 NF Update (PUT or PATCH: taiList, NF status="REGISTERED" ) with new discovered Track Areas (TAs) to the NRF indicating the status of the new AMF changed to REGISTERED. The NRF sends 309 200 OK (NF Profile) to the new AMF to acknowledge.

It will be appreciated that signaling messages, information elements (IEs) and network elements shown in Figs. 1-3, table 1-6 are just as examples, and more or less alternative signaling messages, IE and network elements may be involved according to the embodiments of the present disclosure.

Fig. 4 is a flowchart illustrating a method 400 according to some embodiments of the present disclosure. The method 400 illustrated in Fig. 4 may be performed by a first AMF or an apparatus communicatively coupled to the first AMF. According to the exemplary method 400 illustrated in Fig. 4, the first AMF may receive a notification message from an NRF, as shown in block 402; the message from the NRF may comprise TNL information of a second AMF when the second AMF is added to an AMF set which includes the first AMF, as described with respect to Fig. 3.

According to the notification message from the NRF, the first AMF may send a configuration message to one or more RAN node (e.g., gNodeB or a NG-eNodeB etc. ) , as shown in block 404; the configuration message to one or more RAN node may comprise TNL information of the second AMF, as described with respect to Fig. 3.

In accordance with some exemplary embodiments, the first AMF has SCTP connectivity with one or more RAN node, and the second AMF has no SCTP connectivity with the one or more RAN node. In accordance with some exemplary embodiments, the notification message may comprise status of the second AMF. In accordance with some exemplary embodiments, the first AMF may determine whether send the configuration message to the one or more RAN node based on the received information of the notification message; the first AMF may send the configuration message when the status indicating the second AMF is undiscoverable and no TAI list is included in the notification message. In accordance with some exemplary embodiments, the TNL information may comprise IP address and/or port number; the IP address and/or port number may be included in TNL association address; and the TNL information may further comprise at least one of TNL association usage, TNL address weight factor, and AMF name. In accordance with some exemplary embodiments, the first AMF may subscribe, prior to receiving the notification message, to receiving the notification message from the NRF based on configuration. The above is as described with respect to Fig. 3.

Fig. 5 is a flowchart illustrating a method 500 according to some embodiments of the present disclosure. The method 500 illustrated in Fig. 5 may be performed by a RAN node or an apparatus communicatively coupled to the RAN node. According to the exemplary method 500 illustrated in Fig. 5. The RAN node may receive a configuration message from a first AMF, as shown in block 502; the configuration message from the first AMF may comprise TNL information of a second AMF, as described with respect to Fig. 3.

In accordance with the TNL information in the configuration message, the RAN node may send a message to a second AMF as shown in block 504. The message may initiate the SCTP connectivity with the second AMF, as described with respect to Fig. 3.

In accordance with some exemplary embodiments, the TNL information may comprise IP address and/or port number; the IP address and/or port number may be included in TNL association address; and the TNL information may further comprise at least one of TNL association usage, TNL address weight factor, and AMF name; as described with respect to Fig. 3.

Fig. 6 is a flowchart illustrating a method 600 according to some embodiments of the present disclosure. The method 600 illustrated in Fig. 6 may be performed by a second AMF or an apparatus communicatively coupled to the second AMF. According to the exemplary method 600 illustrated in Fig. 6, the second AMF may send a registration message to an NRF, as shown in block 602. In accordance with some exemplary embodiments, the registration message to the NRF may comprise TNL information of a second AMF to register in the NRF when the second AMF is added to an AMF set, as described with respect to Fig. 3.

In accordance with some exemplary embodiments, the second AMF may receive a message from a RAN node, as shown in block 604. The message may initiate the SCTP connectivity between the RAN node and the second AMF, as described with respect to Fig. 3.

In accordance with some exemplary embodiments, the registration message may comprise one of: amfRegionId, amfSetId, Globally Unique AMF Id, GUAMI. In accordance with some exemplary embodiments TAI list may not be included in the registration message; the registration message may comprise status of the second AMF indicating the second AMF is undiscoverable; the TNL information comprises Internet Protocol, IP, address and/or port number; as described with respect to Fig. 3.

Fig. 7 is a flowchart illustrating a method 700 according to some embodiments of the present disclosure. The method 700 illustrated in Fig. 7 may be performed by an NRF or an apparatus communicatively coupled to the NRF. According to the exemplary method 700 illustrated in Fig. 7, the NRF may receive from a second AMF a registration message, as shown in block 702. In accordance with some exemplary embodiments, the registration message to from the second AMF may comprise TNL information of a second AMF to register in the NRF when the second AMF is added to an AMF set, as described with respect to Fig. 3.

In accordance with some exemplary embodiments, the second NRF may send to a first AMF a notification message, as shown in block 704. The message may comprise TNL information of the second AMF when the AMF set includes the first AMF.

In accordance with some exemplary embodiments, the registration message may comprise one of: amfRegionId, amfSetId, Globally Unique AMF Id, GUAMI; Tracking Area Identity, TAI, list may not be included in the registration message; the registration message may comprise status of the second AMF indicating the second AMF is undiscoverable; the TNL information comprises Internet Protocol, IP, address and/or port number; as described with respect to Fig. 3.

In accordance with some exemplary embodiments, the notification message may comprise status of the second AMF indicating the second AMF is undiscoverable; and may no TAI list be included in the notification message. In accordance with some exemplary embodiments, the TNL information may comprise IP address and/or port number; the IP address and/or port number may be included in TNL association address; and the TNL information may further comprise at least one of TNL association usage, TNL address weight factor, and AMF name. The above is as described with respect to Fig. 3.

The proposed solution according to one or more exemplary embodiments can enable NG control plane be configured automatically and be handled more efficiently.

The various blocks shown in Figs. 4-7 may be viewed as method steps, and/or as operations that result from operation of computer program code, and/or as a plurality of coupled logic circuit elements constructed to carry out the associated function (s) . The schematic flow chart diagrams described above are generally set forth as logical flow chart diagrams. As such, the depicted order and labeled steps are indicative of specific embodiments of the presented methods. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the illustrated methods. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown.

Fig. 8 is a block diagram illustrating an apparatus 800 according to various embodiments of the present disclosure. As shown in Fig. 8, the apparatus 800 may comprise one or more processors such as processor 801 and one or more memories such as memory 802 storing computer program codes 803. The memory 802 may be non-transitory machine/processor/computer readable storage medium. In accordance with some exemplary embodiments, the apparatus 800 may be implemented as an integrated circuit chip or module that can be plugged or installed into a first AMF as described with respect to Fig. 4, a RAN node as described with respect to Fig. 5, a second AMF as described with respect to Fig. 6, and a NRF as described with respect to Fig. 7.

In some implementations, the one or more memories 802 and the computer program codes 803 may be configured to, with the one or more processors 801, cause the apparatus 800 at least to perform any operation of the method as described in connection with Fig. 4. In some implementations, the one or more memories 802 and the computer program codes 803 may be configured to, with the one or more processors 801, cause the apparatus 800 at least to perform any operation of the method as described in connection with Fig. 5. In some implementations, the one or more memories 802 and the computer program codes 803 may be configured to, with the one or more processors 801, cause the apparatus 800 at least to perform any operation of the method as described in connection with Fig. 6. In some implementations, the one or more memories 802 and the computer program codes 803 may be configured to, with the one or more processors 801, cause the apparatus 800 at least to perform any operation of the method as described in connection with Fig. 7.

Alternatively or additionally, the one or more memories 802 and the computer program codes 803 may be configured to, with the one or more processors 801, cause the apparatus 800 at least to perform more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

Fig. 9 is a block diagram illustrating an apparatus 900 according to some embodiments of the present disclosure. The apparatus 900 may be implemented as a first AMF or as a part of the first AMF. As shown in Fig. 9, the apparatus 900 may comprise a receiving unit 901 and a sending unit 902. The receiving unit 901 may be operable to carry out the operation in block 402, and the sending unit 902 may be operable to carry out the operation in block 404. Optionally, the receiving unit 901 and/or the sending unit 902 may be operable to carry out more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

Fig. 10 is a block diagram illustrating an apparatus 1000 according to some embodiments of the present disclosure. The apparatus 1000 may be implemented as a RAN node or as a part of the RAN node. As shown in Fig. 10, the apparatus 1000 may comprise a receiving unit 1001 and a sending unit 1002. The receiving unit 1001 may be operable to carry out the operation in block 502, and the sending unit 1002 may be operable to carry out the optional operation in block 504. Optionally, the sending unit 1001 and/or the receiving unit 1002 may be operable to carry out more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

Fig. 11 is a block diagram illustrating an apparatus 1100 according to some embodiments of the present disclosure. The apparatus 1100 may be implemented as a second AMF or as a part of the second AMF. As shown in Fig. 11, the apparatus 1100 may comprise a sending unit 1101 and a receiving unit 1102. The sending unit 1101 may be operable to carry out the operation in block 602, and the obtaining unit 1102 may be operable to carry out the operation in block 604. Optionally, the sending unit 1101 and/or the receiving unit 1102 may be operable to carry out more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

Fig. 12 is a block diagram illustrating an apparatus 1200 according to some embodiments of the present disclosure. The apparatus 1200 may be implemented as a NRF or as a part of the NRF. As shown in Fig. 12, the apparatus 1200 may comprise a receiving unit 1201 and a sending unit 1202. The receiving unit 1201 may be operable to carry out the operation in block 702, and the sending unit 1202 may be operable to carry out the operation in block 704. Optionally, the receiving unit 1201 and/or the performing unit 1202 may be operable to carry out more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

In general, the various exemplary embodiments may be implemented in hardware or special purpose chips, circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the exemplary embodiments of this disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As such, it should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be practiced in various components such as integrated circuit chips and modules. It should thus be appreciated that the exemplary embodiments of this disclosure may be realized in an apparatus that is embodied as an integrated circuit, where the integrated circuit may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor, a digital signal processor, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this disclosure.

It should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be embodied in computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on a computer readable medium such as a hard disk, optical disk, removable storage media, solid state memory, random access memory (RAM) , etc. As will be appreciated by one of skill in the art, the function of the program modules may be combined or distributed as desired in various embodiments. In addition, the function may be embodied in whole or partly in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA) , and the like.

The present disclosure includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. Various modifications and adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this disclosure.

Claims

A method (400) performed by a first Access and Mobility Management Function, AMF, comprising:

receiving (402) , from a Network Repository Function, NRF, a notification message comprising Transport Network Layer, TNL, information of a second AMF when the second AMF is added to an AMF set which includes the first AMF; and

sending (404) a configuration message comprising TNL information of the second AMF to one or more Radio Access Network, RAN, node.
The method according to claim 1, wherein the first AMF has Stream Control Transmission Protocol, SCTP, connectivity with one or more RAN node, and the second AMF has no SCTP connectivity with the one or more RAN node.
The method according to any claims of 1-2, further comprising:

determining, based on the received information of the notification message, whether send the configuration message to the one or more RAN node.
The method according to claim 3, wherein the received information comprises status of the second AMF.
The method according to any claims 3-4, further comprises sending the configuration message when the status indicating the second AMF is undiscoverable and no Track Area Identifier, TAI, list is included in the notification message.
The method according to any of claims 1-5, wherein the TNL information comprises Internet Protocol, IP, address and/or port number.
The method according to claim 6, wherein the IP address and/or port number are included in TNL association address; and the TNL information further comprises at least one of TNL association usage, TNL address weight factor, and AMF name.
The method according to any of claims 1-7, further comprising:

subscribing, prior to receiving the notification message, to receiving the notification message from the NRF based on configuration.
The method according to any of claims 1-8, wherein the RAN node comprises a gNodeB or a NG-eNodeB.
A method (500) performed by a Radio Access Network, RAN, node, comprising:

receiving (502) , from a first Access and Mobility Management Function, AMF, a configuration message comprising Transport Network Layer, TNL, information of a second AMF; and

sending (504) a message, based on the TNL information, to the second AMF to initiate the Stream Control Transmission Protocol, SCTP, connectivity.
The method according to claim 10, wherein the TNL information comprises Internet Protocol, IP, address and/or port number.
The method according to claim 11, wherein the IP address and/or port number are included in TNL association address; and the TNL information further comprises at least one of TNL association usage, TNL address weight factor, and AMF name.
The method according to any of claims 10-12, wherein the RAN node comprises a gNodeB or a NG-eNodeB.
A method (600) performed by a second Access and Mobility Management Function, AMF, comprising:

sending (602) a registration message comprising Transport Network Layer, TNL, information of the second AMF to register in a Network Repository Function, NRF, when the second AMF is added to an AMF set;

receiving (604) a message to initiate a Stream Control Transmission Protocol, SCTP, connectivity from a Radio Access Network, RAN, node.
The method according to claim 14, wherein the registration message further comprises one of: amfRegionId, amfSetId, Globally Unique AMF Id, GUAMI.
The method according to any of claims 14-15, wherein no Track Area Identifier, TAI, list is included in the registration message.
The method according to any of claims 14-16, wherein the registration message comprises status of the second AMF indicating the second AMF is undiscoverable.
The method according to any of claim 14-17, wherein the TNL information comprises Internet Protocol, IP, address and/or port number.
The method according to any of claims 14-18, wherein the RAN node comprises a gNodeB or a NG-eNodeB.
A method (700) performed by a Network Repository Function, NRF, comprising:

receiving (702) , from a second Access and Mobility Management Function, AMF, a registration message comprising Transport Network Layer, TNL, information to register in the NRF when the second AMF is added to an AMF set;

sending (704) , to a first AMF, a notification message comprising TNL information of the second AMF when the AMF set includes the first AMF.
The method according to claim 20, wherein the registration message comprises one of: amfRegionId, amfSetId, Globally Unique AMF Id, GUAMI.
The method according to any of claims 20-21, wherein no Track Area Identifier, TAI, list is included in the registration message.
The method according to any of claims 20-22, wherein the registration message comprises status of the second AMF indicating the second AMF is undiscoverable.
The method according to any of claims 20-23, wherein the TNL information comprises Internet Protocol, IP, address and/or port number.
The method according to any of claims 20-24, further comprising:

receiving, prior to sending the notification message, a message for subscribing to the notification message from the first AMF; and

the NRF sending the notification message based on the subscription.
A first Access and Mobility Management Function, AMF, apparatus (800) , comprising:

one or more processors (801) ; and

one or more memories (802) comprising computer program codes (803) ,

the one or more memories (802) and the computer program codes (803) configured to, with the one or more processors (801) , cause the first network node (800) at least to perform the method according to any one of claims 1-9.
A Radio Access Network, RAN, node apparatus (800) , comprising:

one or more processors (801) ; and

one or more memories (802) comprising computer program codes (803) ,

the one or more memories (802) and the computer program codes (803) configured to, with the one or more processors (801) , cause the second network node (800) at least to perform the method according to any one of claims 10-13.
A second Access and Mobility Management Function, AMF, apparatus (800) , comprising:

one or more processors (801) ; and

one or more memories (802) comprising computer program codes (803) ,

the one or more memories (802) and the computer program codes (803) configured to, with the one or more processors (801) , cause the third network node (800) at least to perform the method according to any one of claims 14-19.
A Network Repository Function, NRF, apparatus (800) , comprising:

one or more processors (801) ; and

one or more memories (802) comprising computer program codes (803) ,

the one or more memories (802) and the computer program codes (803) configured to, with the one or more processors (801) , cause the database (800) at least to perform the method according to any one of claims 20-25.
A computer-readable medium having computer program codes (803) embodied thereon for use with a computer, wherein the computer program codes (803) comprise codes for performing the method according to any one of claims 1-25.