WO2022053134A1

WO2022053134A1 - User plane entity and control plane entity for exchanging network access node information

Info

Publication number: WO2022053134A1
Application number: PCT/EP2020/075236
Authority: WO
Inventors: Siva VAKEESAR; Ali HAMIDIAN; Seil Jeon; Andrey Krendzel
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2020-09-09
Filing date: 2020-09-09
Publication date: 2022-03-17
Also published as: EP4205420A1

Abstract

The invention relates to communication between a user plane entity and a control plane entity for exchanging network access node information. Using a first control message, the user plane entity can provide information to the control plane entity about the network access nodes to which the user plane entity maintains a communication interface connection. The control plane entity can use the provided information to select a suitable user plane entity to handle traffic of a client device served by a specific network access node. The invention may for example be used to provide enhanced communication and coordination among network functions in a 5G core network, as well as between such network functions and a multi-access edge computing framework.

Description

USER PLANE ENTITY AND CONTROL PLANE ENTITY FOR EXCHANGING NETWORK ACCESS NODE INFORMATION

Technical Field

The invention relates to a user plane entity and a control plane entity for exchanging network access node information. Furthermore, the invention also relates to corresponding methods and a computer program.

Background

Multi-access edge computing (MEC) is generally considered to be a key 5G enabler that allows computing tasks to be processed and executed in appropriate edge application servers (EAS) located in close proximity of a user equipment (UE). The basic tenet is that data generated locally in for example a vehicle-to-anything (V2X) situation is relevant to a particular area given the time urgency of most safety critical applications. For example, car/pedestrian movements need to be locally processed and the results need to be passed on to appropriate road users in a timely manner for any locally collected and processed data to be effective and useful, for instance to avoid an accident.

According to the 3GPP standard, remote driving use case requires that the 3GPP system supports exchange of messages between a UE supporting V2X application and an V2X application server for an absolute speed of up to 250 km/h. Remote driving further requires that maximum end-to-end latency is below 5ms. These strict requirements demonstrate the need for MEC to ensure high reliability and high availability of MEC-V2X application services. In the case of remote driving or tele-operated driving (TOD), to meet high-speed and low- latency requirements, it is logical that an automated remote driver is located in a local edge server, i.e. not in a remote server.

Summary

An objective of embodiments of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions.

The above and further objectives are solved by the subject matter of the independent claims. Further advantageous embodiments of the invention can be found in the dependent claims.

According to a first aspect of the invention, the above mentioned and other objectives are achieved with a user plane entity for a communication system, the user plane entity being configured to

SUBSTITUTE SHEET (RULE 26) maintain a communication interface connection to one or more network access nodes; and transmit a first control message to a control plane entity, wherein the first control message indicates identifiers of the one or more network access nodes to which the user plane entity maintains the communication interface connection.

The communication interface connection can herein be understood to be a reference point or a next generation user plane interface. That the user plane entity maintains a communication interface connection to a network access node can herein be understood to mean that a communication interface is first established with the network access node and then kept active for handling user plane traffic belonging to one or many client devices served by the network access node.

Identifier in any embodiments of the invention may be substituted by identity, identification or identification information.

By receiving those identifiers, the control plane entity knows which network access nodes are available/connected to the UPF. The control plane entity may update this information every time it receives the first control message.

The identifiers of the one or more network access nodes may be global radio access node (RAN) node IDs, e.g. global gNB IDs, global ng-eNB IDs, global Non-3GPP Interworking Function (N3IWF) IDs, or similar.

An advantage of the user plane entity according to the first aspect is that the user plane entity can provide the control plane entity with information about which network access nodes the user plane entity maintains communication interface connections with. In this way, more dynamic information is provided in terms of which user plane entity to choose out of many in order to serve a client device in question that is served by a given network access node. Statically configured information may not correctly reflect a current situation. For example, if a configured communication link between a given user plane entity and a network access node breaks, the statically configured information is misleading unless or until a control plane entity is notified about such a link breakage through a management plane. The dynamic information on the other hand can reflect the current situation correctly and can thereby provide the control plane entity with an improved basis for making routing decisions. In an implementation form of a user plane entity according to the first aspect, the first control message further indicates one or more Data Network Access Identifiers supported by the user plane entity.

An advantage with this implementation form is that it is now possible for the control plane entity to know exactly which user plane entities currently maintain communication interface with a given network access node identified by a data network access identifier serving a client device in question. Thereby, the control plane entity can choose an appropriate user plane entity to carry traffic of a client device in question.

In an implementation form of a user plane entity according to the first aspect, the first control message further indicates performance information of the user plane entity.

An advantage with this implementation form is that the control plane entity can select an appropriate user plane entity to handle a given client device traffic based on the performance of the user plane entity.

In an implementation form of a user plane entity according to the first aspect, the performance information relates to load and/or residual capacity of the user plane entity.

An advantage with this implementation form is that one of the selection criteria of a user plane entity is that it is less loaded while having amble residual capacity when compared to other user plane entities maintaining a communication interface with a network access node serving a client device in question.

In an implementation form of a user plane entity according to the first aspect, the user plane entity is configured to transmit the first control message upon performing at least one of: a N4 interface association setup procedure, a N4 interface association update procedure, an event exposure procedure, and a network function service registration procedure.

An advantage with this implementation form is that dynamic status of the communication links between a given user plane entity and network access node pair and performance information of a user plane entity are notified to the control plane entity using defined procedures. Thereby, simplifying the implementation. In an implementation form of a user plane entity according to the first aspect, the communication interface is a N3 interface; and/or the control plane entity is a session management function.

An advantage with this implementation form is that a session management function can quickly know using control plane mechanism as to which N3 interfaces of a user plane entity are (in)active at a given time instance.

According to a second aspect of the invention for a communication system, the above mentioned and other objectives are achieved with a control plane entity, the control plane entity being configured to receive a set of first control messages from a set of user plane entities, wherein each first control message in the set of first control messages indicates identifiers of one or more network access nodes, wherein a communication interface connection is maintained between the one or more network access nodes and a user plane entity.

An advantage of the control plane entity according to the second aspect is that the control plane entity can get more dynamic information in terms of which user plane entity maintains active communication interface with a given network access node. The control plane entity thereby has an improved basis for making routing decisions.

In an implementation form of a control plane entity according to the second aspect, the control plane entity is further configured to select a user plane entity among the set of user plane entities based on the set of first control messages, wherein the selected user plane entity can serve a client device; and route a Packet Data Unit of the client device to the selected user plane entity.

That a user plane entity can serve a client device can be understood to mean that the user plane entity maintains a communication interface connection to a network access node serving the client device.

An advantage with this implementation form is that a control plane entity can quickly get to know dynamic status of communication links between a given network access node and a user plane entity. This is beneficial as statically configured information may not correctly reflect a current situation. For example, if a configured communication link between a given user plane entity and a network access node breaks, the statically configured information is misleading unless or until a control plane entity is notified about such a link breakage through a management plane. The dynamic status of the communication links hence improves the basis for selecting a suitable user plane entity to handle traffic of a given client device.

In an implementation form of a control plane entity according to the second aspect, the first control message further indicates one or more Data Network Access Identifiers supported by a user plane entity.

An advantage with this implementation form is that it is easy to choose a user plane entity to carry user plane traffic of a client device based on an identifier of a data network access currently serving the client device.

In an implementation form of a control plane entity according to the second aspect, the first control message further indicates performance information of the user plane entity.

An advantage with this implementation form is that one of the selection criteria of a user plane entity is performance related. The control plane entity can thereby select an appropriate user plane entity to handle a given client device traffic based on the performance of the user plane entity.

In an implementation form of a control plane entity according to the second aspect, the performance information relates to load and/or residual capacity of the user plane entity.

In an implementation form of a control plane entity according to the second aspect, the control plane entity is configured to receive the set of first control messages upon performing at least one of: a N4 interface association setup procedure, a N4 interface association update procedure, an event exposure procedure, and a network function service registration procedure.

An advantage with this implementation form is that dynamic status of the communication links between a given user plane entity and network access node pair and performance information of a user plane entity are notified to the control plane entity using defined procedures. Thereby, simplifying the implementation.

According to a third aspect of the invention, the above mentioned and other objectives are achieved with a method for a user plane entity, the method comprises maintaining a communication interface connection to one or more network access nodes; and transmitting a first control message to a control plane entity, wherein the first control message indicates identifiers of the one or more network access nodes to which the user plane entity maintains the communication interface connection.

The method according to the third aspect can be extended into implementation forms corresponding to the implementation forms of the user plane entity according to the first aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the user plane entity.

The advantages of the methods according to the third aspect are the same as those for the corresponding implementation forms of the user plane entity according to the first aspect.

According to a fourth aspect of the invention, the above mentioned and other objectives are achieved with a method for a control plane entity, the method comprises receive a set of first control messages from a set of user plane entities, wherein each first control message in the set of first control messages indicates identifiers of one or more network access nodes, wherein a communication interface connection is maintained between the one or more network access nodes and a user plane entity.

The method according to the fourth aspect can be extended into implementation forms corresponding to the implementation forms of the control plane entity according to the second aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the control plane entity.

The advantages of the methods according to the fourth aspect are the same as those for the corresponding implementation forms of the control plane entity according to the second aspect.

According to a fifth aspect of the invention for a communication system, the above mentioned and other objectives are achieved with a control plane entity, the control plane entity being configured to receive a second control message from an application entity, wherein the second control message indicates identifiers of one or more application servers.

The one or more application servers may be application servers in a given geographical location, where the geographical location may be defined by e.g. geographical coordinates, cell/gNB coverage area, RAN notification area, or tracking area.

An advantage of the control plane entity according to the second aspect is that the control plane entity knows the identities of application servers that are associated with a given application entity. Thereby, enabling routing of user plane traffic pertaining to a given application entity to appropriate application servers, e.g. to appropriate servers in the given geographical location that is in close proximity to a user equipment.

In an implementation form of a control plane entity according to the fifth aspect, the second control message further indicates identifiers of one or more services provided by the one or more application servers.

An advantage with this implementation form is that the control plane entity knows what services are provided by a given application server so that appropriate routing of user plane traffic based on service is possible. When the one or more application servers are in a given geographical location, the control plane entity further knows what services are provided by a given application server in the given geographical location.

In an implementation form of a control plane entity according to the fifth aspect, the second control message further indicates load and residual capacity of the one or more application servers.

An advantage with this implementation form is that selection of application server can now be based on whether a given application server is less loaded while having amble residual capacity and further being close enough proximity to handle a given client device traffic.

In an implementation form of a control plane entity according to the fifth aspect, the control plane entity is further configured to select an application server among the one or more application servers based on the second control messages, wherein the selected application server can serve a client device; and route a Packet Data Unit of the client device to the selected application server. That an application server can serve a client device can herein be understood to mean that the application server can provide services that are requested by the client device and that the application server has enough residual capacity and further is located in close proximity to a client device.

An advantage with this implementation form is that traffic balancing is enabled by routing traffic to a less loaded application server that has amble residual capacity to handle a given client device traffic.

According to a sixth aspect of the invention, the above mentioned and other objectives are achieved with a method for a control plane entity, the method comprises receiving a second control message from an application entity, wherein the second control message indicates identifiers of one or more application servers.

The method according to the sixth aspect can be extended into implementation forms corresponding to the implementation forms of the control plane entity according to the fifth aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the control plane entity.

The advantages of the methods according to the sixth aspect are the same as those for the corresponding implementation forms of the control plane entity according to the fifth aspect.

The invention also relates to a computer program, characterized in program code, which when run by at least one processor causes said at least one processor to execute any method according to embodiments of the invention. Further, the invention also relates to a computer program product comprising a computer readable medium and said mentioned computer program, wherein said computer program is included in the computer readable medium, and comprises of one or more from the group: ROM (Read-Only Memory), PROM (Programmable ROM), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically EPROM) and hard disk drive.

Further applications and advantages of the embodiments of the invention will be apparent from the following detailed description. Brief Description of the Drawings

The appended drawings are intended to clarify and explain different embodiments of the invention, in which:

- Fig. 1 shows a user plane entity according to an embodiment of the invention;

- Fig. 2 shows a method for a user plane entity according to an embodiment of the invention;

- Fig. 3 shows a control plane entity according to an embodiment of the invention;

- Fig. 4 shows a method for a control plane entity according to an embodiment of the invention;

- Fig. 5 shows a communication network according to an embodiment of the invention;

- Fig. 6 shows signalling between a user plane entity and a control plane entity according to an embodiment of the invention;

- Fig. 7 shows signalling between a set of user plane entities and a control plane entity according to an embodiment of the invention;

- Fig. 8 shows signaling between a control plane entity and an application entity according to an embodiment of the invention;

- Fig. 9 shows a parameter provisioning procedure according to an embodiment of the invention;

- Fig. 10 shows an application function advertisement procedure according to an embodiment of the invention;

- Fig. 11 shows an application function request associated with traffic routing according to an embodiment of the invention;

- Fig. 12 shows an application function request indicating quality-of-service according to an embodiment of the invention.

Detailed Description

In 5G systems, the 5G core network (5GC) is responsible for routing traffic to meet quality-of- service (QoS) requirements of a user equipment (UE) application as configured by an application function. To ensure service continuity at the required QoS, the 5GC needs to have up-to-date information to decide how to dynamically route traffic depending on the QoS requirements of the UE application and dynamic load conditions of different (edge) application servers ((E)ASs) that can provide a required service.

The session management function (SMF) is responsible for making decisions in terms of how to route traffic to meet QoS requirements of a UE application as configured by an application function through a policy control function (PCF). Within the 5GC, there exists different mechanisms for an SMF to collect information about radio access network (RAN) and user plane function (UPF) that can help the SMF to make these routing decisions, e.g. to choose an appropriate UPF to handle a particular traffic. The collected information is mainly configured through an operations, administration and maintenance (OAM) entity, i.e. the collected information is mainly static.

During UE mobility in connected mode, the 5GC should be able to determine whether UPF change is required and the instantaneous load of different UPFs for 5GC to select an appropriate target UPF without relying heavily on OAM-based configurations. The UPF may be a packet data unit (PDU) session anchor (PSA) UPF or intermediate UPF or uplink classifier or branching point UPF. Furthermore, an SMF should also be able to quickly decide on an (E)AS that it can make use of based on load and locations of (E)ASs, especially when anycast address is used by one or many (E)ASs, and quickly configure an appropriate uplink classifier or multi-home branching point UPF.

In the case of coordination between the SMF and UPFs, existing mechanisms support initial service discovery and status notification using a network repository function (NRF). However, there is no support for subsequent service updates or to exchange dynamic information. In addition, although UPF Provisioning information makes use of NRF, the current network function (NF) profile information for UPFs does not include all the required information. It is for example assumed that any UPF will maintain connection with all network access nodes within an SMF service area. This may not always be true given the dynamic deployment of different UPFs and network access nodes, especially in the case of public network integrated non-public networks (PNI-NPN). Furthermore, existing mechanisms do not support the exchange of dynamic information such as changes in DNAI support list and current load of an UPF.

In the case of coordination between the SMF and (E)ASs, domain name system/fully qualified domain name (DNS/FQDN) queries are conventionally used by the 5GC NFs to find appropriate (E)AS functionalities from a multi-access edge computing (MEC) application function (AF) which knows locations and addresses of each deployed (E)AS. However, this leads to numerous DNS/FQDN queries. The inventors have identified a need to eliminate or minimize the number of DNS/FQDN queries to avoid flooding of DNS/FQDN queries. The communication between 5GC NFs and the MEC framework (such as a system related to (E)AS I MEC AF) is therefore proposed to be extended, to make it possible for 5GC NFs to identify an appropriate (E)AS without having to rely on DNS/FQDN queries. A new channel between MEC application function (AF) and 5GC NFs is proposed, allowing an MEC AF to advertise its services to the 5GC NFs through NRF/ network exposure function (NEF) such that unnecessary flooding of DNS enquiries can be minimised or eliminated.

Fig. 1 shows a user plane entity 100 for a communication system 500 according to an embodiment of the invention. In the embodiment shown in Fig. 1 , the user plane entity 100 comprises a processor 102 which can be coupled to an internal or external memory 104 with communication means 106 known in the art. The memory 104 may store program code that, when being executed, causes the processor 102 to performing the functions and actions described herein. The user plane entity 100 further comprises input means 108 and output means 110, which are both coupled to the processor 102 with communication means 106 known in the art. The communication means 106 may be bus.

The user plane entity 100 may be a standalone entity or may be comprised in one or more other network entities in the communication system 500. Such as, there are one or a plurality of user plane entities in the communication system 500. These user plane entities are distributed over the communication system 500.

That the user plane entity 100 is configured to perform certain functions and actions can in this invention be understood to mean that the user plane entity 100 comprises suitable means, such as e.g. the processor 102, configured to perform said functions and actions.

According to embodiments of the invention the user plane entity 100 is configured to maintain a communication interface 550 connection to one or more network access nodes 600a, 600b, ..., 600n. The user plane entity 100 is further configured to transmit a first control message 510 to a control plane entity 300, wherein the first control message 510 indicates identifiers of the one or more network access nodes 600a, 600b, ..., 600n to which the user plane entity 100 maintains the communication interface 550 connection.

Fig. 2 shows a flow chart of a corresponding method 200 which may be executed in a user plane entity 100, such as the one shown in Fig. 1. The method 200 comprises maintaining 202 a communication interface 550 connection to one or more network access nodes 600a, 600b, ..., 600n. The method 200 further comprises transmitting 204 a first control message 510 to a control plane entity 300, wherein the first control message 510 indicates identifiers of the one or more network access nodes 600a, 600b, ..., 600n to which the user plane entity 100 maintains the communication interface 550 connection. Fig. 3 shows a control plane entity 300 for a communication system 500 according to an embodiment of the invention. In the embodiment shown in Fig. 3, the control plane entity 300 comprises a processor 302 which can be coupled to an internal or external memory 304 with communication means 306 known in the art. The memory 304 may store program code that, when being executed, causes the processor 302 to performing the functions and actions described herein. The control plane entity 300 further comprises input means 308 and output means 310, which are both coupled to the processor 302 with communication means 306 known in the art.

The control plane entity 300 may be a standalone entity or may be comprised in one or more network entities in the communication system 500. Such as, there are one or a plurality of control plane entities in the communication system 500. These control plane entities are distributed over the communication system 500.

That the control plane entity 300 is configured to perform certain functions and actions can in this invention be understood to mean that the control plane entity 300 comprises suitable means, such as e.g. the processor 302, configured to perform said functions and actions.

According to embodiments of the invention the control plane entity 300 is configured to receive a set of first control messages 510a, 510b, ... , 51 On from a set of user plane entities 100a, 100b, ... , 10On, wherein each first control message 51 On in the set of first control messages 510a, 510b, ... , 51 On indicates identifiers of one or more network access nodes 600a, 600b, ..., 600n, wherein a communication interface 550n connection is maintained between the one or more network access nodes 600a, 600b, ..., 600n and a user plane entity 100n.

Fig. 4 shows a corresponding method 400 which may be executed in a control plane entity 300, such as the one shown in Fig. 3. The method 400 comprises receiving 402 a set of first control messages 510a, 510b, ... , 51 On from a set of user plane entities 100a, 100b, ... , 10On, wherein each first control message 51 On in the set of first control messages 510a, 510b, ... , 510n indicates identifiers of one or more network access nodes 600a, 600b, ..., 600n, wherein a communication interface 550n connection is maintained between the one or more network access nodes 600a, 600b, ..., 600n and a user plane entity 100n.

Fig. 5 shows a communication system 500 according to embodiments of the invention. In the shown embodiment, the communication system 500 comprises the control plane entity 300 and a user plane entity 100 which are configured to communicate over an interface 560. The user plane entity 100 is further configured to maintain a communication interface 550 connection to one or more network access nodes 600a, 600b, ..., 600n. Each network access node 600a; 600b; ...; 600n can further serve one or more client devices 610 of which only one is shown in Fig. 5. In embodiments, the communication interface 550 is an N3 interface according to the 3GPP standard. The interface 560 is an N4 interface according to the 3GPP standard.

According to embodiments of the invention the user plane entity 100 is configured to transmit a first control message 510 to the control plane entity 300. The first control message 510 indicates identifiers of the one or more network access nodes 600a, 600b, ..., 600n to which the user plane entity 100 maintains the communication interface 550 connection.

The control plane entity 300 receives the first control message from user plane entity 100 and hence the indicated identifiers of the one or more network access nodes 600a, 600b, ..., 600n. The control plane entity 300 is thereby informed about which network access nodes 600a, 600b, ..., 600n the user plane entity 100 has a connection to.

Based on the first control message 510, the control plane entity 300 may determine that the user plane entity 100 can serve the client device 610, i.e. that the user plane entity 100 maintains a communication interface 550 connection with a network access node 600n serving the client device 610. The control plane entity 300 may further route a PDU of the client device 610 to the user plane entity 100. In this way, the information in the first message 510 according to the invention can be used by the control plane entity 300 to select a suitable user plane entity 100n for routing traffic of the client device 610 that is currently served by a given network access node 600n.

Fig. 6 shows signaling between the user plane entity 100 and the control plane entity 300 for exchanging information associated with the user plane entity 100 according to an embodiment of the invention. In embodiments, the user plane entity 100 may be a user plane function (UPF) and the control plane entity 300 may be a session management function (SMF).

In step I in Fig. 6, the user plane entity 100 maintains a communication interface 550 connection to one or more network access nodes 600a, 600b, ..., 600n, as schematically shown in Fig. 5. The communication interface 550 connection can further be understood to be a reference point or a next generation user plane interface. In embodiments, the communication interface 550 is a N3 interface according to the 3GPP standard. In step II in Fig. 6, the user plane entity 100 transmits a first message 510 to the control plane entity 300. The first message 510 indicates identifiers of the one or more network access nodes 600a, 600b, ..., 600n to which the user plane entity 100 maintains the communication interface 550 connection. The identifiers may be global RAN node IDs, e.g. global gNB IDs, global ng- eNB IDs, global N3IWF IDs, or similar. Thus, the user plane entity 100 can with the first message 510 inform the control plane entity 300 about which network access nodes 600a, 600b, ..., 600n the user plane entity 100 has a connection to and can communicate with. This is beneficial as not all user plane entities may maintain a communication interface 550 connection with every network access nodes 600a, 600b, ..., 600n in an area served by the control plane entity 300, e.g. due to load balancing reasons or support for a public network integrated non-public network. The information in the first message 510 can be used by the control plane entity 300 to select a suitable user plane entity 100n to serve a client device 610, as will be further described below with reference to Fig. 7.

The user plane entity 100 may include additional information in the first message 510 which can be useful to the control plane entity 300 when selecting a suitable user plane entity 100n. The first control message 510 may hence further indicates one or more data network access identifiers (DNAIs) supported by the user plane entity 100. The DNAI(s) can be used by the control plane entity 300 to perform user plane entity 100 selection and/or re-selection and to allow the control plane entity 300 to route user traffic to a local access to a data network (such as the control plane entity 300 routes user traffic to an (E)AS which is identified by a DNAI), where the data network can be identified with a DNAI. The PCF may provide DNAI(s) in the policy and charging control (PCC) rule(s) to the control plane entity 300, taking into account the AF request and the local routing indication from the PDU session policy control subscription information. Upon receiving a PCC rule which contains the traffic steering control information, the control plane entity 300 provides the information to the user plane entity 100 for the enforcement. The potential location of application is expressed as a list of DNAI(s). The DNAI(s) may be used for user plane entity 100 (re)selection.

The first control message 510 may further indicate performance information of the user plane entity 100. The performance information may relate to load and/or residual capacity of the user plane entity 100 and may indicate information such as for example one or more of the following:

■ Number of incoming/outgoing data packets,

■ Data volume of incoming/outgoing data packets,

■ Incoming/outgoing data packet loss,

■ Round-trip delay, and

■ Incoming/outgoing link usage. The performance information may be associated with an interface maintained by the user plane entity 100 to another network entity, e.g. an N3, N6 or N9 interface as defined in the 3GPP standard. For example, the performance information may indicate number of incoming GPRS tunneling protocol (GTP) data packets on the N3 interface, data volume of incoming/outgoing GTP data packets per QoS level on the N3 interface, incoming/outgoing link usage on the N6 interface, round-trip packet delay between the user plane entity 100 and a client device, and similar. The performance information may hence correspond to performance related measurements pertaining to the user plane entity 100 and its related interfaces such as the N3, N6 and N9 interfaces, and may in embodiments correspond to performance related measurements as defined in the 3GPP. In this way, performance related measurements may be exchanged on the N4 interface between the user plane entity 100 and the control plane entity 300.

The above indicated information are a non-exhaustive list of possible performance information of the user plane entity 100 and other available performance indicators can also be used without deviating from the scope of the invention. The performance information indicated in the first message 510 may help the control plane entity 300 to dynamically choose an appropriate user plane entity 100n to handle a particular traffic.

The user plane entity 100 may transmit the first message 510 to the control plane entity 300 upon performing at least one of a N4 interface 560 association setup procedure, a N4 interface 560 association update procedure, an event exposure procedure, and a network function service registration procedure. The first message 510 may be or be comprised in a request message, a response message, a notification message, or similar of one of the above- mentioned procedures. In this way, the procedures may be augmented such that the additional information about the user plane entity 100 according to the invention is provided to the control plane entity 300 during the procedure.

In the N4 interface 560 association setup or update procedure, the first message 510 may correspond to or be comprised in a N4 interface association setup or update request/response message. For example, a N4 interface association setup or update response message may be extended to comprise the above described information indicated in the first message 510. In this case, the user plane entity 100 may transmit the first message 510 to the control plane entity 300 upon receiving a N4 interface association setup or update request message from the control plane entity 300. The control plane entity 300 may hence trigger the user plane entity 100 to transmit the first message 510 during the N4 interface 560 association setup or update procedure. In order to limit the number of first messages 510 that are generated to update instantaneous load or residual capacity of a user plane entity 100, the control plane entity 300 may set and indicate one or many thresholds for load and/or residual capacity so that whenever a threshold is passed, the user plane entity 100 will generate the first message 510. The control plane entity 300 may use N4 Association Setup or Update Request message for this purpose if it triggers the respective procedures.

The event exposure procedure may be a procedure for notifying an entity about the occurrence of an event using a notification message. The first message 510 may correspond to or be comprised in the notification message. The control plane entity 300 may subscribe to the user plane entity 100 for an event, for example an event associated with at least one of a change in network access nodes 600a, 600b, ..., 600n to which the user plane entity 100 maintains communication interface 550 connections, a change in DNAIs supported by the user plane entity 100, and a change or deviation of performance information by one or more thresholds pertaining to the user plane entity 100. Such as, some network access nodes lose their connections to the user plane entity 100, some new network access nodes get/establish/maintain their connections to the user plane entity 100, DNAI list supported by the user plane entity 100 are changed. The one or more thresholds may be set by the control plane entity 300. By subscribing to the event, the control plane entity 300 will be notified by the user plane entity 100 when the user plane entity 100 detects such an event. The control plane entity 300 may hence receive a notification message when the configuration and/or performance of the user plane entity 100 changes. Thereby, allowing the control plane entity 300 to make dynamic traffic routing decisions.

The user plane entity 100 may further transmit the first message 510 to the control plane entity 300 during a network function service registration procedure. The network function service registration procedure may include the control plane entity 300 subscribing to notifications from a network repository function (NRF), which provides network function service registration and discovery. When the user plane entity 100 registers to the NRF, the control plane entity 300 may, based on the subscription, be notified by the NRF about the user plane entity 100. The network function service registration procedure may be performed in a known way, e.g. using the Nnrf_NFManagement_NFStatus Subscribe, Nnrf_NFManagement_NFRegister, and Nnrf_NFManagement_NFStatusNotify operations. When the user plane entity 100 registers to the NRF, the user plane entity 100 may in addition to conventional information in the registration operation provide the information indicated in the first message 510 according to the invention. Thus, the user plane entity 100 may in addition to information such as its network function type, fully qualified domain name (FQDN) or IP address of its N4 interface, provisioning information, etc., include identifiers of the one or more network access nodes 600a, 600b, ..., 600n to which the user plane entity 100 maintains communication interface 550 connections, as well as optionally DNAIs supported by the user plane entity 100 and performance information of the user plane entity 100. Based on the subscription by the control plane entity 300, the NRF may provide a notification message to the control plane entity 300 about the user plane entity 100. The notification message may include the additional information provided by the user plane entity 100 during the registration to the NRF, i.e. identifiers of the one or more network access nodes 600a, 600b, ..., 600n to which the user plane entity 100 maintains communication interface 550 connections, as well as optionally DNAIs supported by the user plane entity 100 and performance information of the user plane entity 100.

Fig. 7 shows signaling between the control plane entity 300 and a set of user plane entities 100a, 100b, ... , 100n according to an embodiment of the invention.

In step I in Fig. 7, the control plane entity 300 receives a set of first control messages 510a, 510b, ... , 51 On from the set of user plane entities 100a, 100b, ... , 100n. Each first control message 51 On in the set of first control messages 510a, 510b, ... , 51 On indicates identifiers of one or more network access nodes 600a, 600b, ..., 600n to which the user plane entity 100n maintains communication interface 550 connections. The set of first control messages 510a, 510b, ... , 51 On may be received essentially at the same time or within a predetermined time period.

In step II in Fig. 7, the control plane entity 300 selects a user plane entity 100n among the set of user plane entities 100a, 100b, ... , 100n based on the set of first control messages 510a, 510b, ... , 51 On. The selected user plane entity 100n can serve a client device 610, i.e. the selected user plane entity 100n maintains a communication interface 550 connection to a network access node 600n which serves the client device 610. Based on the content of the first control messages 510a, 510b, ... , 510n, the control plane entity 300 can hence identify a suitable user plane entity 100n to handle traffic of the client device 610. For example, the control plane entity 300 may from the DNAIs and global RAN node IDs indicated in the first control messages 510a, 510b, ... , 51 On identify a user plane entity 100n that can support a particular DNAI and has connectivity with the network access node 600n currently serving the client device 610. The control plane entity 300 may further from performance information indicated in the first control messages 510a, 510b, ... , 51 On identify a user plane entity 100n with low load and having amble residual capacity to handle the traffic of the client device 610. In step III, the control plane entity 300 routes a PDU of the client device 610 to the selected user plane entity 100n. The selected user plane entity 100n is thereby used to handle traffic of the client device 610, i.e. traffic to and from the client device 610 is routed via the selected user plane entity 100n. As the user plane entity 100n has been selected based on the content of the first control messages 510a, 510b, ... , 51 On, the selected user plane entity 100n is suitable to handle the traffic of the client device 610 and can e.g. support a requested DNAI and provide connection to the network access node 600n currently serving the client device 610, and further has spare capacity.

One or more of the above steps are optional. Such as step III is optional. The control plane entity 300 may interact with the client device 610 according to needing. For other embodiments, one or more of the steps in each embodiment could also be optional.

According to embodiments of the invention a service provisioning procedure is introduced which allows a control plane entity 700 to acquire information associated with application servers. Fig. 8 shows signaling between the control plane entity 700 and an application entity 800 according to such an embodiment. In embodiments, the control plane entity 700 may be a session management function (SMF), a policy control function (PCF), or a network exposure function (NEF), and the application entity 800 may be an application function (AF).

In step I in Fig. 8, the control plane entity 700 receives a second control message 540 from the application entity 800. The second control message 540 indicates identifiers of one or more application servers such as IP address, anycast address, medium access control (MAC) address, DNAI, application-level identifiers. The second control message 540 may further indicate at least one of identifiers of one or more services provided by the one or more application servers, load and residual capacity of the one or more application servers, supported DNAI-list per (E)AS, and geographical locations of each (E)AS, e.g. as geographical coordinates, cell/gNB coverage area, RAN notification area, or tracking area. The second control message 540 may further indicate latency information such as e.g. average end-to-end latency of application-specific packet reaching a given (E)AS.

Based on the second control messages 540, the control plane entity 700 selects an application server among the one or more application servers, in step II in Fig. 8. The control plane entity 700 may select the application server by processing the information derived from the second control messages 540 to determine which of the one or more application servers are capable of and/or suitable to serve a client device 610 for a given service, as well as optionally at a given client device location defined by e.g. geographical coordinates, cell/gNB coverage area, RAN notification area, or tracking area. Thus, the selected application server can serve the client device 610, i.e. the selected application server can provide services that are requested by the client device 610 and the selected application server may further have enough residual capacity to serve the client device 610. The selected application server may be located close enough to the client device 610, such as physically located in close proximity to the client device 610 or in the same or next network as the client device 610.

For this to happen, it is assumed that the client device 610 gets the anycast address of application servers providing a particular service. This can be either configured through periodic UE configuration update procedure at the time of UE registration or by the client device 610 initiating a DNS query. Once found, the client device 610 can generate traffic with an anycast address that is destined to any suitable application server. It is up to the control plane entity 700 to dynamically route traffic to appropriate application servers depending on current working load, residual capacity that is available in a given application server, load of UPFs involved, and latency of N3/N6 interfaces. The control plane entity 700 may make use of uplink classifier functionality or IPv6 multi-homing for routing traffic through different user plane entities 100 dynamically.

In step III in Fig. 8, the control plane entity 700 routes a PDU of the client device 610 to the selected application server. In other words, the selection in step II is used to determine to which application server of one or more applications server to route traffic for a specific client device 610.

According to embodiments of the invention, enhanced communication and coordination among 5GC NFs and between 5GC NFs and the MEC framework is provided, allowing an SMF to make decision in terms of how to route a given UE’s user plane traffic given the underlying conditions of both the 5G network and different (E)ASs that can provide a given service.

For this to happen, it is assumed that a UE gets the anycast address of (E)ASs providing a particular service in a given geographical location. This can be either configured through periodic UE configuration update procedure at the time of UE registration or by expecting a UE to initiate a DNS query. Once found, a UE can generate traffic with an anycast address that is destined to any suitable (E)ASs. It is up to the SMF to dynamically route traffic to appropriate (E)ASs depending on current working load, residual capacity that is available in a given (E)AS, load of UPFs involved, and latency of N3/N6 interfaces. The SMF may make use of uplink classifier functionality or IPv6 multi-homing for routing traffic through different UPFs dynamically by timely creating/updating forwarding action rule (FAR) of traffic which is from a user equipment and is meeting specific packet detection rule (PDR).

Further details related to the service provisioning procedure and the exchange of application server information according to the invention will now be described in a 3GPP 5G context with reference to Figs. 9-12. The control plane entity 700 according to the invention may correspond to any one of a PCF, a SMF or a NEF in the scenarios below and be configured to perform any of the described functions of these entities. In a similar way, the application entity 800 according to the invention may correspond to an AF in the scenarios below and may be configured to perform any of the described function of the AF.

Fig. 9 shows a new MEC parameter provisioning procedure per subscriber according to an embodiment of the invention. This new procedure allows an MEC AF to advertise its MEC services. The parameters that are exchanged as part of the procedure by an MEC AF is provided below:

Service operation name: Nnef_MEC_ParameterProvision_Create

Description of Service operation: The consumer configures MEC related parameters for a particular MEC service.

Inputs: AF ID, UE IDs (generic public subscription identifier (GPSI)), MEC application ID, MEC Service ID, AF-service-identifiers, transaction reference ID, (E)AS FQDNs, (E)AS IP addresses, supported DNAI-list per (E)AS.

Inputs (optional): Instantaneous load, residual capacity.

Outputs: Operation execution result indication.

These inputs may be included in the Nnef_MEC_ParameterProvision_Create request. These outputs may be included in the Nnef_MEC_ParameterProvision_Create response.

Other service operation such as Nnef_MEC_ParameterProvision_Update/delete can be obtained according to a similar procedure of Nnef_MEC_ParameterProvision_Create. These are also shown in Fig. 9.

The procedure as illustrated in Fig. 9 allows an external party such as an AF to provision the information, e.g. MEC service specific parameters. The service specific information consists of information to support the specific service in the 5G system. Provisioned data can be used by the other consumer NFs such as an SMF. An NF such as an SMF subscribes to unified data management (UDM) notifications of MEC service updates. The subscription is assumed to take place before step 1 in Fig. 9. Step 1 : the AF provides one or more parameter(s) pertaining to one or many MEC services to be created or updated in a Nnef_MEC_ParameterProvision_Create or Nnef_MEC_ ParameterProvision_Update request to the NEF. The NEF checks whether the requestor is allowed to perform the requested service operation by checking the requestor's identifier, i.e. AF ID. The AF may further request to delete parameters related to a MEC service by sending a Nnef_MEC ParameterProvision_Delete request to the NEF.

Step 2: If the AF is authorised by the NEF to provision the parameters, the NEF requests to create, update and store, or delete the provisioned parameters as part of the subscriber data through Nudm_MEC_ParameterProvision_Create, Nudm_MEC _ParameterProvision_Update or Nudm_MEC _ParameterProvision_Delete request message, the message includes the provisioned data and NEF reference ID.

If the AF is not authorised to provision the parameters, then the NEF continues directly to step 6 indicating in the Nnef_MEC_ParameterProvision_Create/Update/Delete response message the reason for the failure. Step 7 does not apply in this case.

Step 3: UDM may read from UDR using Nudr_DM_Query, corresponding subscription information in order to validate required data updates and authorize these changes for this UE subscriber or group of UE subscribers for the corresponding AF.

Step 4: If the AF is authorised by the UDM to provision the parameters for this subscriber, the UDM resolves the GPSI to subscription permanent identifier (SUPI), and requests to create, update, or delete the provisioned parameters as part of the subscriber data via a Nudr_DM_Create/Update/Delete request message, the message includes the provisioned data. UDR stores the provisioned data as part of the UE and/or group subscription data and responds with Nudr_DM_Create/Update/Delete Response message. If the AF is not authorised to provision the parameters, then the UDM continues in step 5 indicating the reason of failure in a Nudm_MEC_ParameterProvision_Create/Update/Delete Response message and step 7 is not executed. The failure may be understood to mean that the AF is not authorised to provision the parameters.

The UDM may use the AF ID received from the NEF in step 2 to relate the received parameter with a particular subscribed data network name (DNN) and/or single-network slice selection assistance information (S-NSSAI). The UDM stores the SMF-associated parameters under corresponding session management subscription data type. Each parameter or parameter set may be associated with a validity time. The validity time is stored at the UDM/UDR and in each of the NFs, to which parameters are provisioned, e.g. in AMF or SMF. Upon expiration of the validity time, each node deletes the parameters autonomously without explicit signaling.

Step 5: UDM responds to the request from the NEF with a Nudm_MEC_ParameterProvision_ Create/Update/Delete response. If the procedure failed, a cause value in the response indicates the reason.

Step 6: NEF responds to the request from the AF with a Nnef_MEC_ParameterProvision_ Create/Update/Delete response. If the procedure failed, a cause value in the response indicates the reason.

Step 7: Conditional, this step occurs only after successful step 4. UDM notifies the subscribed NFs, e.g. AMFs, SMFs, etc., of the MEC service parameters pertaining to a UE or group of UEs through a Nudm_SDM_Notification Notify message.

If the NF is a SMF, the UDM performs Nudm_SDM_Notification (such as including at least one of SUPI or internal group identifier, AF ID, UE IDs (GPSI), AF-service-identifiers, transaction reference ID, (E)AS FQDN, (E)AS IP addresses, supported DNAI-list per (E)AS, SMF- associated parameter set, DNN/S-NSSAI, etc.) service operation.

The SMF stores the received AF-associated parameters and associates them with a PDU session based on the DNN and S-NSSAI included in the message from UDM. The SMF may use the MEC service parameters as follows. SMF configures the UPF accordingly. In a given SMF service area, an SMF can identify the UPF to connect to a given (E)AS providing certain MEC service based on DNAI-support list and/or whether a given UPF maintains N3 connection with a gNB that currently serves or is going to serve a UE. Based on instantaneous load and residual capacity of each (E)AS, an SMF will dynamically route traffic to different (E)ASs, especially in the case of session breakout connectivity model, as long as policy and charging control (PCC) rules are in place to support such an operation by an SMF. This may require dynamic creation/updating of forwarding action rule (FAR) of user equipment traffic meeting a given PDR by an SMF in relation to an uplink classifier/branching point UPF involved controlling as to which PSA UPF traffic of particular characteristics needs to be forwarded so that underutilized (E)ASs can be used. Suppose a UE application has identified and has been interacting with one or many (E)ASs, the SMF can dynamically update FAR for traffic meeting given PDR of an uplink classifier/branching point UPF to route traffic through different PSA UPFs depending on their load and residual capacity of each (E)AS. For example, a PSA UPF that is lightly loaded and has sufficient residual capacity can get more traffic routed when compared to a PSA UPF that is heavily loaded with a little residual capacity available.

An uplink classifier may refer to UL CL, or an uplink classifier UPF. A branching point UPF may also refer to a branching point UPF, multi-home branching point UPF, or IPv6 multi-home branching point UPF.

In order to dynamically route traffic to different (E)ASs depending on their dynamic load, residual capacity, or proximity to the UE in question, an appropriate weight factor can be used by an SMF. The given application service is the one a given UE is interested in This can balance traffic of each (E)AS. Dynamic creation and updating of FAR at uplink classifier or branching point UPF by the SMF can make use of such weight factor.

The intention is thus for an AF to advertises its services in terms of which (E)AS is providing a given service, identity/FQDN and IP addresses of each such (E)AS, and current load and residual capacity of each (E)AS. This will help an SMF to correctly route UE traffic to an appropriate (E)AS depending on current load and residual capacity of each (E)AS providing a given MEC service that a UE in question is interested in.

In an embodiment, an AF can register itself to an NRF in terms of what services it provides, information about associated (E)ASs such as DNAI support list of each (E)ASs (which may also refer to supported DNAI-list per (E)AS), geographical location of each (E)AS, Anycast/IP/MAC addresses, instantaneous load and residual capacity of each involved (E)AS. A new procedure for such AF advertisement of its services through an NRF is shown in Fig. 10.

The following takes place when an SMF expects to be informed of AFs available in the network providing a given service pertaining to a given S-NSSAI/DNN set or supporting a given DNAI.

Step 1 : A consumer such as an SMF, AMF, PCF issues a Nnrf_NFManagement_ NFStatusSubscribe service operation providing the target AF Provisioning information it is interested in, such information consists of a given service pertaining to a given S-NSSAI/DNN set or supporting one or many DNAIs an SMF is interested in, the FQDN or IP address of each (E)AS that provides a given MEC service pertaining to a given S-NSSAI/DNN set, instantaneous load and residual capacity of each (E)AS that passes one or more thresholds set by the consumer. Step 2: The NRF issues Nnrf_NFManagement_NFStatusNotify with the list of AFs that currently meet the consumer such as SMF subscription. This notification indicates the subset of the target AF Provisioning information that is supported by each AF.

Step 3: The following takes place when a new AF instance is deployed and registers with a 5GC.

Step 4: The AF instance issues a Nnrf_NFManagement_NFRegister request operation providing at least one of its NF type, MEC services provided and their identities, the FQDN or IP address and geographical location of each (E)AS that provides a given MEC service pertaining to a given S-NSSAI/DNN set that a consumer such as an SMF, AMF, PCF is interested in, instantaneous load and residual capacity of each (E)AS that passes one or more threshold set by the consumer, supported DNAI-list of each (E)AS and the UPF Provisioning information configured in step 3.

Step 5: Based on the subscription in step 1 , the NRF issues a Nnrf_NFManagement_NFStatus notify operation to all consumers such as SMFs, AMFs, and PCFs with a subscription matching the AF Provisioning information of the new AF.

A further way to achieve the goal of getting an AF to pass information related to at least one of what services it provides, information about associated (E)ASs such as DNAI support list of each (E)ASs, IP addresses, instantaneous load, geographical location and residual capacity of each involved (E)AS on to the 5GC, is through augmented AF requests. Fig. 11 shows an augmented AF request to influence traffic routing for sessions according to an embodiment of the invention. The message shown in step 2 of Fig.11 may be the augmented AF request. Geographical location of each (E)AS helps the control plane entity to choose an (E)AS that stays in close proximity to a user equipment. Other criteria to be met by an (E)AS is already described earlier.

The operations shown in step 1 to 5 in Fig. 11 are operations for an AF request in 3GPP standard. However, the operations in steps 2, 3a, 4 and 5 have been extended to further include information related to at least one of services the AF provides, information about associated (E)ASs such as DNAI support list of each (E)ASs, MAC and IP addresses, and instantaneous load and residual capacity of each involved (E)AS, as indicated in Fig. 11. Step 1 : The AF creates an AF request.

Step 2: The AF sends its request to the NEF. If the AF is trusted, the request may be sent directly from the AF to the PCF (not shown in Fig. 11). In this case, the AF reaches the PCF selected for the existing PDU Session by configuration or by invoking Nbsf_management_ Discovery service and step 3 is not performed. The request in step 2 additionally include information related to at least one of services the AF provides, information about associated (E)ASs such as DNAI support list of each (E)ASs and their geographical locations (e.g. geographical coordinates, cell/gNB area, RAN notification area, tracking area, etc.), MAC and IP addresses, and instantaneous load and residual capacity of each involved (E)AS.

Step 3: In step 3a the NEF stores/updates/removes information in the UDR. In the case of Nnef_Trafficlnfluence_Create or Update: The NEF stores the AF request information in the UDR (Data Set = Application Data; Data Subset = AF traffic influence request information, Data Key = AF Transaction Internal ID, S-NSSAI and DNN and/or Internal Group Identifier or SUPI). In the case of Nnef_Trafficlnfluence_delete: The NEF deletes the AF requirements in the UDR (Data Set = Application Data; Data Subset = AF traffic influence request information, Data Key = AF Transaction Internal ID). The NEF further responds to the AF in step 3b.

Step 4: The PCF(s) that have subscribed to modifications of AF requests (Data Set = Application Data; Data Subset = AF traffic influence request information, Data Key = S-NSSAI and DNN and/or Internal Group Identifier or SUPI) receive(s) a Nudr_DM_Notify notification of data change from the UDR.

Step 5: The PCF determines if existing PDU Sessions are potentially impacted by the AF request. For each of these PDU Sessions, the PCF updates the SMF with corresponding new PCC rule(s) by invoking Npcf_SMPolicyControl_UpdateNotify service operation.

The intention is for an SMF to keep this information so that when anycast address is used, an SMF can decide how to route traffic dynamically depending on current load and residualcapacity of (E)ASs that provide similar service as long as related PCC rules are in place. This may require an SMF to dynamically configure FAR for a given PDR at any involved uplink classifier or branching point UPF in terms of how to split UE traffic. The case of dynamically routing UE traffic to one or many (E)ASs or remote ASs by regularly updating/configuring FAR for traffic meeting particular PDR depending on proximity to UE location, latency involved, load and residual capacity of (E)ASs works better when all these (E)ASs and remote ASs are synchronized in term of what they process for a given UE application. This means that any (E)AS can process UE traffic in any order and provide a cumulative collective response after collective processing.

Fig. 12 shows an augmented AF request indicating required QoS according to an embodiment of the invention. The operations shown in step 1 to 6 in Fig. 12 are operations for an AF request. However, the operations in steps 1 , 3 and 6 have been extended to further include information related to at least one of services the AF provides, information about associated (E)ASs such as DNAI support list of each (E)ASs, MAC and IP addresses, and instantaneous load and residual capacity of each involved (E)AS.

In step 1 , the AF sends a Nnef_AFsessionWithQoS_Create request to the NEF. The Nnef_AFsessionWithQoS_Create request has been extended to include Service IDs, (E)ASs IDs, etc., as indicated in Fig. 12. With the modified Nnef_AFsessionWithQoS_Create request, an AF can pass information related to what services it provides, information about associated (E)ASs such as DNAI support list of each (E)ASs, MAC and IP addresses, instantaneous load and residual capacity of each involved (E)AS on to the 5GC. In step 3 and step 6, this information is further passed on from the NEF to the PCF(s) in an extended Npcf_PolicyAuthorisation_Create request and from the PCF(s) to the SMF(s) in an extended Npcf_SMPolicyControl_UpdateNotify operation, respectively.

Whenever a load or residual capacity reaches one or many threshold or changes is noticed in terms of services provided or information about associated (E)ASs such as DNAI support list of each (E)AS, corresponding SMFs get notified by a PCF. In this way, the SMFs will have up- to-date information in terms of load and residual capacities of different (E)ASs providing a given service.

With a help of load and residual capacity related information pertaining to each (E)AS and corresponding identifiers, e.g., MAC/IP Addresses, of each (E)AS provided by an AF, it is now possible for an SMF to determine as to how different user plane traffic of a UE can be offloaded to different (E)ASs depending on their load and residual capacities. It is the SMF that manages QoS of a session and hence, it is the appropriate entity to make these dynamic routing decisions of UE traffic by dynamically configuring/updating FAR of traffic meeting particular PDR at each uplink classifier or branching point UPF.

The user plane entity 100 herein may be denoted as a user plane function (UPF). The control plane entity 300 herein may be denoted as a session management function (SMF), the user plane entity 700 may be denoted as a SMF, a policy control function (PCF), or a network exposure function (NEF). The application entity 800 herein may be denoted as an application function (AF). The UPF, the SMF, the PCF, the NEF, and the AF may be functions configured for communication in 3GPP related LTE and LTE-Advanced, in WiMAX and its evolution, and in fifth generation wireless technologies, such as new radio (NR).

Furthermore, any method according to embodiments of the invention may be implemented in a computer program, having code means, which when run by processing means causes the processing means to execute the steps of the method. The computer program is included in a computer readable medium of a computer program product. The computer readable medium may comprise essentially any memory, such as a ROM (Read-Only Memory), a PROM (Programmable Read-Only Memory), an EPROM (Erasable PROM), a Flash memory, an EEPROM (Electrically Erasable PROM), or a hard disk drive.

Moreover, it is realized by the skilled person that embodiments of the user plane entity 100, the control plane entity 300; 700, and the application entity 800 comprises the necessary communication capabilities in the form of e.g., functions, means, units, elements, etc., for performing the solution. Examples of other such means, units, elements and functions comprise: processors, memory, buffers, control logic, encoders, decoders, rate matchers, derate matchers, mapping units, multipliers, decision units, selecting units, switches, interleavers, de-interleavers, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiver units, transmitter units, DSPs, MSDs, TCM encoder, TCM decoder, power supply units, power feeders, communication interfaces, communication protocols, etc. which are suitably arranged together for performing the solution.

Especially, the processor(s) of the user plane entity 100, the control plane entity 300; 700, and the application entity 800 may comprise, e.g., one or more instances of a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The expression “processor” may thus represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above. The processing circuitry may further perform data processing functions for inputting, outputting, and processing of data comprising data buffering and device control functions, such as call processing control, user interface control, or the like.

A communications apparatus is provided, including at least one of the following: a bus, a processor, a storage medium, a bus interface, a network adapter, a user interface, and an antenna, where the bus is configured to connect the processor, the storage medium, the bus interface, and the user interface; the processor is configured to perform the above method; the storage medium is configured to store an operating system and to-be-sent or to-be-received data; the bus interface is connected to the network adapter; the network adapter is configured to implement a signal processing function of a physical layer in a wireless communications network; the user interface is configured to be connected to a user input device; and the antenna is configured to send and receive a signal.

Another aspect of this application provides a computer-readable storage medium, where the computer-readable storage medium stores an instruction, and when the computer-readable storage medium runs on a computer, the computer performs the above method.

Another aspect of this application provides a computer program product including an instruction, where when the computer program product runs on a computer, the computer performs the above method.

Another aspect of this application provides a computer program, where when the computer program runs on a computer, the computer performs the above method.

The foregoing embodiments may be all or partially implemented by using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, the embodiments may be all or partially implemented in a form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of this application are all or partially generated. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable apparatuses. The computer instructions may be stored in a computer readable storage medium, or may be transmitted from a computer readable storage medium to another computer readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired (for example, a coaxial cable, an optical fiber, or a digital subscriber line (DSL)) or wireless (for example, infrared, radio, or microwave) manner. The computer readable storage medium may be any usable medium accessible by a computer, or may be a data storage device, such as a server or a data center, integrating one or more usable media. The usable medium may be a magnetic medium (for example, a floppy disk, a hard disk, or a magnetic tape), an optical medium (for example, a DVD), a semiconductor medium (for example, a solid state disk Solid State Disk (SSD)), or the like.

The term "and/or" in this specification describes only an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists. In addition, the character "/" in this specification generally indicates an "or" relationship between the associated objects.

A person of ordinary skill in the art may be aware that, units and algorithm steps in the examples described with reference to the embodiments disclosed in this specification may be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on particular applications and design constraints of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application. It may be clearly understood by a person skilled in the art that, for the purpose of convenient and brief description, for a detailed working process of the foregoing system, apparatus, and unit, refer to a corresponding process in the foregoing method embodiments. Details are not described herein again.

Finally, it should be understood that the invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

1. A user plane entity (100) for a communication system (500), the user plane entity (100) being configured to maintain a communication interface (550) connection to one or more network access nodes (600a, 600b, ..., 600n); and transmit a first control message (510) to a control plane entity (300), wherein the first control message (510) indicates identifiers of the one or more network access nodes (600a, 600b, ..., 600n) to which the user plane entity (100) maintains the communication interface (550) connection.

2. The user plane entity (100) according to claim 1 , wherein the first control message (510) further indicates one or more Data Network Access Identifiers supported by the user plane entity (100).

3. The user plane entity (100) according to claim 1 or 2, wherein the first control message (510) further indicates performance information of the user plane entity (100).

4. The user plane entity (100) according to claim 3, wherein the performance information relates to load and/or residual capacity of the user plane entity (100).

5. The user plane entity (100) according to any one of the preceding claims, wherein the user plane entity (100) is configured to transmit the first control message (510) upon performing at least one of: a N4 interface (560) association setup procedure, a N4 interface (560) association update procedure, an event exposure procedure, and a network function service registration procedure.

6. The user plane entity (100) according to any one of the preceding claims, wherein the communication interface (550) is a N3 interface; and/or the control plane entity (300) is a session management function.

7. A control plane entity (300) for a communication system (500), the control plane entity (300) being configured to receive a set of first control messages (510a, 510b, ... , 51 On) from a set of user plane entities (100a, 100b, ... , 100n), wherein each first control message (51 On) in the set of first control messages (510a, 510b, ... , 51 On) indicates identifiers of one or more network access nodes (600a, 600b, ..., 600n), wherein a communication interface (550n) connection is maintained between the one or more network access nodes (600a, 600b, ..., 600n) and a user plane entity (100n).

8. The control plane entity (300) according to claim 7, wherein the control plane entity (300) is configured to select a user plane entity (100n) among the set of user plane entities (100a, 100b, ... , 100n) based on the set of first control messages (510a, 510b, ... , 51 On), wherein the selected user plane entity (100n) can serve a client device (610); and route a Packet Data Unit of the client device (610) to the selected user plane entity (100n).

9. The control plane entity (300) according to claim 7 or 8, wherein the first control message (51 On) further indicates one or more Data Network Access Identifiers supported by a user plane entity (100n).

10. The control plane entity (300) according to any one of claims 7 to 9, wherein the first control message (51 On) further indicates performance information of the user plane entity (100n).

11. The control plane entity (300) according to claim 10, wherein the performance information relates to load and/or residual capacity of the user plane entity (100n).

12. The control plane entity (300) according to any one of claims 7 to 11 , wherein the control plane entity (300) is configured to receive the set of first control messages (510a, 510b, ... , 51 On) upon performing at least one of: a N4 interface (560) association setup procedure, a N4 interface (560) association update procedure, an event exposure procedure, and a network function service registration procedure.

13. A method (200) for a user plane entity (100), the method (200) comprising maintaining (202) a communication interface (550) connection to one or more network access nodes (600a, 600b, ..., 600n); and transmitting (204) a first control message (510) to a control plane entity (300), wherein the first control message (510) indicates identifiers of the one or more network access nodes (600a, 600b, ..., 600n) to which the user plane entity (100) maintains the communication interface (550) connection.

14. A method (400) for a control plane entity (300), the method (400) comprising receiving (402) a set of first control messages (510a, 510b, ... , 51 On) from a set of user plane entities (100a, 100b, ... , 100n), wherein each first control message (51 On) in the set of first control messages (510a, 510b, ... , 510n) indicates identifiers of one or more network access nodes (600a, 600b, ..., 600n), wherein a communication interface (550n) connection is maintained between the one or more network access nodes (600a, 600b, ..., 600n) and a user plane entity (100n).

15. A computer program with a program code for performing a method according to any one of claims 13 or 14 when the computer program runs on a computer.