WO2022143373A1

WO2022143373A1 - Communication method and node

Info

Publication number: WO2022143373A1
Application number: PCT/CN2021/140715
Authority: WO
Inventors: 李汉成; 胡伟华; 吴问付; 周汉
Original assignee: 华为技术有限公司
Priority date: 2020-12-28
Filing date: 2021-12-23
Publication date: 2022-07-07
Also published as: CN114698025A

Abstract

The present application relates to the technical field of communications. Disclosed are a communication method and a node, which are used for solving the problem of, during session establishment or terminal device switching, there being a need to configure a forwarding rule for a plurality of intermediate nodes on a transmission path of application layer messages such as a GTP-U message, resulting in complex configuration. The method comprises: a source node encapsulating a message in an application layer message, wherein a message header of the application layer message comprises an identifier of a destination node of the application layer message; and the source node sending the application layer message to a first intermediate node, wherein the first intermediate node is located on a path, between the source node and the destination node, for transmitting the application layer message.

Description

A communication method and node

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application filed on December 28, 2020 with the Intellectual Property Office of the People's Republic of China, the application number is 202011576733.1, and the application name is "a communication method and node", the entire contents of which are incorporated herein by reference Applying.

technical field

The embodiments of the present application relate to the field of communication technologies, and in particular, to a communication method and a node.

Background technique

At present, in the 5th generation mobile networks (5G) system, uplink general packet radio service (GPRS) tunneling protocol users can be established between access network equipment and user plane functional network elements. face (GRPS tunnelling protocol user plane, GTP-U) tunnel and downlink GTP-U tunnel. In downlink data transmission, the data network can send downlink packets to the user plane functional network elements, and the user plane functional network elements forward the downlink packets to the access network equipment through the downlink GTP-U tunnel, and the access network equipment then forwards the downlink packets to the access network equipment. The downlink message is forwarded to the terminal device. In uplink data transmission, the terminal equipment can send uplink packets to the access network equipment, and the access network equipment forwards the uplink packets to the user plane function network element through the uplink GTP-U tunnel, and the user plane function network element then forwards the uplink packet to the user plane function network element. The uplink message is forwarded to the data network.

However, the existing GTP-U tunnel is a tunnel between nodes, and the header of the GTP-U packet only has the tunnel identifier transmitted to the next hop node. However, for a session, there may be multiple intermediate nodes between the access network device and the user plane functional network element, which requires the configuration of forwarding rules for multiple intermediate nodes on the path for transmitting GTP-U packets. In addition, when the terminal device is switched, there may also be multiple intermediate nodes between the two access network devices before and after the terminal device is switched, and it is also necessary to transmit GTP-U messages between the two access network devices. The forwarding rules are configured on multiple intermediate nodes on the path of the text. Too many configurations will affect the efficiency of session establishment and terminal device switching, bring about higher delay, and affect user experience.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a communication method and node, which are used to solve the problem that when a session is established or a terminal device is switched, it is necessary to configure forwarding rules for multiple intermediate nodes on the transmission path of application layer packets such as GTP-U packets. complicated question.

In a first aspect, the present application provides a communication method, the method includes: a source node encapsulates a packet in an application layer packet, and a packet header of the application layer packet includes the purpose of the application layer packet The identifier of the node; the source node sends the application layer packet to a first intermediate node, and the first intermediate node is located on the path between the source node and the destination node for transmitting the application layer packet. Optionally, the application layer message is a GTP-U message.

Using the above method, by introducing the identifier of the destination node into the packet header of the application layer packet such as the GTP-U packet, the intermediate node located on the path for transmitting the application layer packet between the source node and the destination node can be based on the The identifier of the destination node in the packet header of the application layer packet determines the forwarding path for forwarding. It is not necessary to configure forwarding rules such as GTP-U tunnels on the intermediate nodes, which reduces the configuration complexity during session establishment and terminal device switching. It is beneficial to improve the efficiency of session establishment and terminal device switching, and improve user experience.

In a possible design, the packet header of the application layer packet includes the tunnel identifier corresponding to the destination node. Optionally, the tunnel identifier includes the identifier of the destination node.

In the above design, the tunnel identifier corresponding to the destination node can be carried in the packet header of the application packet to further identify the tunnel for the destination node to receive the application layer packet, and at the same time, the tunnel identifier corresponding to the destination node can be extended to achieve the purpose of passing the The tunnel identifier corresponding to the node indicates the identifier of the destination node, which is beneficial to ensure reliable transmission of application layer packets.

In a possible design, the method further includes: the source node receives a session message from a session management function network element, where the session message includes the identifier of the destination node; or, the source node receives a session message from the session management function network element; A handover command for the management function network element, where the handover command includes the identifier of the destination node.

In a possible design, the source node is a first access network device, and the destination node is a user plane functional network element; or, the source node is a user plane functional network element, and the destination node is the first access network element. an access network device; or, the source node is a first access network device, and the destination node is a second access network device.

In the above design, when a session is established or a terminal device is switched, the session management function network element can configure the identity of the destination node to the source node through a session message or a switching command, so that the source node can encapsulate the identity of the destination node in the application layer message. This avoids configuring forwarding rules for intermediate nodes located on the path for transmitting application layer packets between the source node and the destination node, which is beneficial to improve the efficiency of session establishment and terminal device switching.

In a second aspect, the present application provides a communication method, the method includes: a source node encapsulates a message in an application layer message, and a message header of the application layer message includes an identifier of one or more intermediate nodes , the one or more intermediate nodes are located on the path for transmitting the application layer packet between the source node and the destination node; the source node sends the application layer packet to the first intermediate node, and the first intermediate node sends the application layer packet. An intermediate node is located on the path for transmitting the application layer message between the source node and the destination node. Optionally, the application layer message is a GTP-U message.

By adopting the above method, the identifier of one or more intermediate nodes located on the path for transmitting the application layer packet between the source node and the destination node is introduced into the packet header of the application layer packet such as the GTP-U packet, so that the intermediate The node can determine the forwarding path based on the identifiers of one or more intermediate nodes included in the packet header of the application layer packet and forward it. It is not necessary to configure the forwarding rules such as GTP-U tunnel on the intermediate node, which reduces the time required for session establishment and termination. The configuration complexity during device switching is conducive to improving the efficiency of session establishment and terminal device switching, and improving user experience.

In one possible design, the one or more intermediate nodes may include the first intermediate node.

In the above design, the identifier of the first intermediate node connected to the source node may be included in the packet header of the application layer packet, or may not be included in the packet header of the application layer packet. When the identifier of the node is not included in the packet header of the application layer packet, it is beneficial to reduce the size of the packet header of the application layer packet and reduce the transmission overhead of the application layer packet.

In a possible design, the packet header of the application layer packet further includes the tunnel identifier corresponding to the destination node.

In the above design, the packet header of the application layer packet includes the tunnel identifier corresponding to the destination node, which can further identify the tunnel through which the destination node receives the application layer packet, which is beneficial to ensure reliable transmission of the application layer packet.

In a possible design, the method further includes: the source node receives a session message from a session management function network element, the session message includes the identifiers of the one or more intermediate nodes; or, the source The node receives a handover command from the session management function network element, the handover command including the identity of the one or more intermediate nodes.

In the above design, when the session is established or the terminal device is switched, the session management function network element can use the session message or switching command to transfer the information of one or more intermediate nodes on the path of the application layer message transmission between the source node and the destination node. The identification is configured to the source node, so that the source node can encapsulate the identification of one or more intermediate nodes in the packet header of the application layer packet, so as to avoid the transmission of the application layer packet between the source node and the destination node. The intermediate node configures the forwarding rules, which is beneficial to improve the efficiency of session establishment and terminal device switching.

In a third aspect, the present application provides a communication method. The method includes: a first intermediate node receives an application layer packet from a source node, and a packet header of the application layer packet includes a message of the application layer packet. The identifier of the destination node; the first intermediate node forwards the application layer message according to the identifier of the destination node. Optionally, the application layer message is a GTP-U message.

In a possible design, forwarding the application layer packet by the first intermediate node according to the identifier of the destination node includes: acquiring the application layer packet by the first intermediate node according to the identifier of the destination node The next-hop node where the layer message is transmitted to the destination node; the first intermediate node sends the application layer message to the next-hop node.

In a fourth aspect, the present application provides a communication method, the method includes: a first intermediate node receives an application-layer packet from a source node, and a packet header of the application-layer packet includes the information of one or more intermediate nodes. identifier, the one or more intermediate nodes are located on the path for transmitting the application layer packet between the source node and the destination node; the first intermediate node forwards the packet according to the identifiers of the one or more intermediate nodes the application layer message. Optionally, the application layer message is a GTP-U message.

In a possible design, the first intermediate node forwarding the application layer packet according to the identifiers of the one or more intermediate nodes includes: the first intermediate node according to the one or more intermediate nodes The identifier of the node is used to obtain the next hop node for transmitting the application layer message to the destination node; the first intermediate node sends the application layer message to the next hop node.

In a possible design, the method further includes: the first intermediate node deletes the identifier of the first intermediate node from the identifiers of the one or more intermediate nodes, or deletes the one or more intermediate nodes The identifier of the next hop node of the first intermediate node in the identifier of the node.

In a fifth aspect, an embodiment of the present application provides a communication device, the device has a function of implementing each step in the first aspect or the second aspect, and the function can be implemented by hardware or by executing corresponding software in hardware. The hardware or software includes one or more units (modules) corresponding to the above functions, such as a communication unit and a processing unit.

In one possible design, the device may be a chip or an integrated circuit.

In a possible design, the apparatus includes a processor and an interface circuit, the processor is coupled to the interface circuit, and is configured to implement the functions of each step in the first aspect or the second aspect. It can be understood that the interface circuit can be a transceiver or an input-output interface. The apparatus may further comprise a memory storing a program executable by the processor for implementing the functions of the steps in the first aspect or the second aspect above.

In one possible design, the device may be a source node.

In a sixth aspect, an embodiment of the present application provides a communication device, the device has a function of implementing each step in the third aspect or the fourth aspect, and the function can be implemented by hardware or by executing corresponding software in hardware. The hardware or software includes one or more units (modules) corresponding to the above functions, such as a communication unit and a processing unit.

In one possible design, the device may be a chip or an integrated circuit.

In a possible design, the apparatus includes a processor and an interface circuit, the processor is coupled to the interface circuit, and is configured to implement the functions of each step in the third aspect or the fourth aspect. It can be understood that the interface circuit can be a transceiver or an input-output interface. The apparatus may further comprise a memory storing a program executable by the processor for implementing the functions of the steps in the third or fourth aspect above.

In one possible design, the device may be the first intermediate node.

In a seventh aspect, an embodiment of the present application provides a communication system, including a source node and a first intermediate node, wherein the source node has a function of executing the method provided in the first aspect or the second aspect, the first The intermediate node has the function of executing the method provided by the third aspect or the fourth aspect.

In an eighth aspect, an embodiment of the present application further provides a computer program, which, when the computer program runs on a computer, causes the computer to execute the method provided in any one of the first to fourth aspects.

In a ninth aspect, an embodiment of the present application further provides a computer-readable storage medium, where a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a computer, the computer is made to execute the above-mentioned first The method provided by any of the to fourth aspects.

In a tenth aspect, an embodiment of the present application further provides a chip, where the chip is configured to read a computer program stored in a memory and execute the method provided in any one of the first to fourth aspects above.

In an eleventh aspect, an embodiment of the present application further provides a chip system, where the chip system includes a processor for supporting a computer device to implement the method provided in any one of the above-mentioned first to fourth aspects. In a possible design, the chip system further includes a memory for storing necessary programs and data of the computer device. The chip system can be composed of chips, and can also include chips and other discrete devices.

For the technical effects that can be achieved by the third aspect to the eleventh aspect, please refer to the technical effects that can be achieved by the first aspect or the second aspect, which will not be repeated here.

Description of drawings

1 is a schematic diagram of a network architecture provided by an embodiment of the present application;

2 is a schematic diagram of an existing GTP-U message encapsulation format;

3 is a schematic diagram of an uplink GTP-U tunnel of a PDU session provided by an embodiment of the present application;

FIG. 4 is one of the schematic diagrams of a PDU session creation process provided by an embodiment of the present application;

FIG. 5 is one of the schematic diagrams of the temporary GTP-U tunnel in the UE handover process provided by the embodiment of the present application;

FIG. 6 is one of schematic diagrams of a communication process provided by an embodiment of the present application;

FIG. 7 is one of schematic diagrams of GTP-U message encapsulation formats provided by an embodiment of the present application;

FIG. 8 is the second schematic diagram of the GTP-U message encapsulation format provided by the embodiment of the present application;

FIG. 9 is the third schematic diagram of the GTP-U message encapsulation format provided by the embodiment of the present application;

FIG. 10 is the second schematic diagram of the communication process provided by the embodiment of the present application;

FIG. 11 is a fourth schematic diagram of a GTP-U packet encapsulation format provided by an embodiment of the present application;

12 is a schematic diagram of a GTP-U tunnel of a PDU session provided by an embodiment of the present application;

FIG. 13 is the second schematic diagram of the PDU session creation process provided by the embodiment of the present application;

14 is the second schematic diagram of a temporary GTP-U tunnel in a UE handover process provided by an embodiment of the present application;

15 is a schematic diagram of a UE handover process provided by an embodiment of the present application;

FIG. 16 is one of schematic structural diagrams of a communication device provided by an embodiment of the present application;

FIG. 17 is the second schematic structural diagram of a communication device provided by an embodiment of the present application.

Detailed ways

The technical solutions provided in the embodiments of the present application may be applicable to the 5G network architecture shown in FIG. 1 . The 5G network architecture shown in Figure 1 may include three parts, namely the terminal equipment part, the data network (DN) part and the operator network part.

The operator network may include a network exposure function (NEF) network element, a policy control function (PCF) network element, a unified data management (unified data management, UDM) network element, and an application function (application function) network element. function, AF) network element, access and mobility management function (access and mobility management function, AMF) network element, session management function (session management function, SMF) network element, (wireless) access network ((radio) access network, (R)AN) and user plane function (user plane function, UPF) network elements, etc. In the above-mentioned operator network, the part other than the (radio) access network part may be referred to as the core network part. For convenience of description, the following description is given by taking (R)AN called RAN as an example.

Terminal equipment (also known as user equipment (UE)) is a device with wireless transceiver functions that can be deployed on land, including indoor or outdoor, handheld or vehicle-mounted; it can also be deployed on water (such as ships). etc.); can also be deployed in the air (eg on airplanes, balloons, satellites, etc.). The terminal device may be a mobile phone (mobile phone), a tablet computer (pad), a computer with wireless transceiver function, a virtual reality (virtual reality, VR) terminal, an augmented reality (augmented reality, AR) terminal, an industrial control (industrial control) wireless terminals in ), wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grid, wireless terminals in transportation safety , wireless terminals in smart cities, wireless terminals in smart homes, etc.

The above-mentioned terminal device can establish a connection with the operator network through an interface (eg, N1, etc.) provided by the operator network, and use the data and/or voice services provided by the operator network. The terminal device can also access the DN through the operator's network, and use the operator's service deployed on the DN and/or the service provided by a third party. The above-mentioned third party may be a service provider other than the operator's network and the terminal device, and may provide other services such as data and/or voice for the terminal device. Wherein, the specific expression form of the above third party can be specifically determined according to the actual application scenario, and is not limited here.

An access network device, also known as a (radio) access network ((R)AN) device, is a device that provides wireless communication functions for terminals. Access network equipment includes, but is not limited to, the next-generation base station (g nodeB, gNB), evolved node B (evolved node B, eNB), radio network controller (radio network controller, RNC), node B ( node B, NB), base station controller (BSC), base transceiver station (BTS), home base station (for example, home evolved nodeB, or home node B, HNB), base band unit (base band) unit, BBU), transmission point (transmitting and receiving point, TRP), transmitting point (transmitting point, TP), mobile switching center, etc.

The AMF network element is the control plane network element provided by the operator's network. It is responsible for the access control and mobility management of the terminal equipment accessing the operator's network, such as the management of mobility status, the allocation of user temporary identities, and the authentication and authorization of users. .

The SMF network element is a control plane network element provided by the operator network, and is responsible for managing the protocol data unit (PDU) session of the terminal device. A PDU session is a channel for transmitting PDUs. Terminal devices need to communicate PDUs with the DN through the PDU session. The PDU session is established, maintained and deleted by the SMF network element. SMF network elements include session management (such as session establishment, modification and release, including GTP-U tunnel maintenance between UPF and RAN), selection and control of UPF network elements, service and session continuity (SSC) Session-related functions such as mode selection and roaming.

The UPF network element is the gateway provided by the operator, and is the gateway for the communication between the operator's network and the DN. UPF network elements include user plane-related functions such as data packet routing and transmission, packet inspection, service usage reporting, quality of service (QoS) processing, legal interception, uplink data packet detection, and downlink data packet storage.

DN, also known as packet data network (PDN), is a network outside the operator's network. The operator's network can access multiple DNs, and a variety of services can be deployed on the DNs, which can provide Services such as data and/or voice.

The UDM network element is the control plane network element provided by the operator, which is responsible for storing the subscriber permanent identifier (SUPI), security context (security context), subscription data and other information of the subscriber in the operator's network. The information stored by the UDM network element can be used for authentication and authorization of terminal equipment to access the operator's network.

The NEF network element is the control plane network element provided by the operator. The NEF network element opens the external interface of the operator's network to the third party in a secure manner. When the SMF network element needs to communicate with a third-party network element, the NEF network element can be used as a relay for the communication between the SMF network element and the third-party network element.

The PCF network element is a control plane function provided by the operator, and is used to provide the SMF network element with the policy of the PDU session. The policies may include charging-related policies, QoS-related policies, authorization-related policies, and the like.

The AF network element is a functional network element that provides various business services. It can interact with the core network through the NEF network element, and can interact with the policy management framework for policy management, such as providing routing rules and processing policies to the core network.

The communication interface N9 among Nnef, Npcf, Nudm, Naf, Nudr, Namf, Nsmf, N1, N2, N3, N4, N6, and the unshown UPF network elements in FIG. 1 is an interface serial number. For the meanings of these interface serial numbers, refer to the meanings defined in the 3GPP standard protocol, which is not limited here.

It can be understood that the above network elements or functions may be network elements in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (eg, a cloud platform). Optionally, the foregoing network element or function may be implemented by one device, or may be implemented jointly by multiple devices, or may be a functional module in one device, which is not specifically limited in this embodiment of the present application.

In addition, the above-mentioned 5G network architecture is only an example of a possible network architecture to which the technical solutions provided in this application are applicable, and the technical solutions provided in this application can also be applied to future network architectures or other similar network architectures, such as 6G network architectures, etc. .

The existing GTP-U tunnel is a tunnel between nodes, and the GTP-U tunnel can be identified by the IP address and tunnel identifier (such as tunnel endpoint identifier (TEID)) carried in the header of the GTP-U packet. As shown in Figure 2, it is a schematic diagram of the existing GTP-U packet encapsulation format, which can be carried by the IP/UDP header field in the packet header (non-payload part) of the GTP-U packet. The destination IP address and the TEID carried in the TEID field identify the GTP-U tunnel through which the GTP-U packet is transmitted.

Specifically, for a PDU session, the SMF network element will create a GTP-U tunnel for each segment between the RAN and the UPF network element for the PDU session, including the uplink GTP-U tunnel for each segment between the RAN and the UPF network element, and Downlink GTP-U tunnels in each segment between UPF network elements and RAN. Take the upstream GTP-U tunnel of the PDU session shown in Figure 3 as an example, including the GTP-U tunnel 2 of the N3 interface between the RAN and the I-UPF network element (through the IP address of the I-UPF network element and the upstream TEID2 identification), and the upstream GTP-U tunnel 1 of the N9 interface between the I-UPF network element and the UPF network element (identified by the IP address of the UPF network element and the upstream TEID1 identification). The I-UPF network element is an intermediate UPF network element located between the RAN and the UPF network element, and plays the role of forwarding the GTP-U message sent by the RAN to the UPF network element.

As shown in Figure 4, still taking the networking architecture in Figure 3 as an example, it is assumed that the I-UPF network element is managed by the I-SMF network element, and the UPF network element is managed by the SMF network element (the I-UPF network element and the SMF network element in Figure 3). The UPF network element is managed by the SMF network element at the same time. If the I-UPF network element and the UPF network element are managed by the SMF network element at the same time, the signaling between the I-SMF network element and the SMF network element in the following PDU session creation process can be omitted. interactive steps), the specific PDU session creation process may include:

S401: The RAN forwards a session creation request (eg, a PDU session creation request) from the UE to the AMF network element.

S402: The AMF network element forwards the session creation request to the selected I-SMF network element.

As an example: the AMF network element may create a session management (session management, SM) context request through the PDU session, and forward the session creation request to the I-SMF network element, that is, transparently transmit the session creation request to the I-SMF network element , wherein the session creation request is carried in the PDU session creation session management context request.

S403: The I-SMF network element and the selected I-UPF network element perform N4 session creation/modification request and response interaction, and configure the uplink tunnel endpoint identifier and the downlink tunnel endpoint identifier of the I-UPF network element.

Specifically, after receiving the session creation request, the I-SMF network element selects the I-UPF network element. If the I-SMF network element allocates the uplink tunnel endpoint identifier and the downlink tunnel endpoint identifier to the I-UPF network element, the I-SMF network element indicates the uplink tunnel endpoint identifier in the N4 session creation/modification request sent to the I-UPF network element. The tunnel endpoint identifier and the downlink tunnel endpoint identifier; if the I-UPF network element allocates the uplink tunnel endpoint identifier and the downlink tunnel endpoint identifier, the I-UPF network element will create/modify the N4 session sent to the I-SMF network element The response (also referred to as N4 session creation/modification response) indicates the identifier of the uplink tunnel endpoint and the identifier of the downlink tunnel endpoint.

S404: The I-SMF network element forwards the session creation request to the SMF network element, and indicates the downlink tunnel information of the I-UPF network element (including the I-UPF network element's downlink tunnel information) in the session creation request. IP address and downstream tunnel endpoint identification).

S405: The SMF network element and the selected UPF network element perform an N4 session creation/modification request and response interaction, and configure the uplink tunnel endpoint identifier of the UPF network element.

Specifically, after receiving the session creation request, the SMF network element selects the UPF network element. If the SMF network element assigns the uplink tunnel endpoint identifier to the UPF network element, the SMF network element indicates the uplink tunnel endpoint identifier in the N4 session creation/modification request sent to the UPF network element; if the UPF network element assigns the uplink tunnel endpoint identifier identifier, the UPF network element will indicate the uplink tunnel endpoint identifier in the N4 session creation/modification response sent to the SMF network element.

S406: The SMF network element sends a session creation response (such as a PDU session creation response) to the I-SMF network element, and indicates the uplink tunnel information (including the UPF network element) of the UPF network element in the session creation response IP address and upstream tunnel endpoint identifier).

S407: The I-SMF network element sends the session establishment response to the AMF network element, and indicates in the session establishment response the uplink tunnel information of the I-UPF network element (including the I-UPF network element's IP address and upstream tunnel endpoint ID).

As an example, the I-SMF network element may create a session management context response (also referred to as a PDU session creation session management context response) through a PDU session, and send the session creation response to the AMF network element, that is, the session is established. The response is transparently transmitted to the AMF network element, wherein the session establishment response is carried in the PDU session establishment session management context response.

S408: The AMF network element sends a session request (eg, a PDU session request) to the RAN, where the session request includes information indicated in the session creation response, such as uplink tunnel information of the I-UPF network element.

S409: The RAN allocates a downlink tunnel endpoint identifier.

S410: The RAN sends a session request (eg, a PDU session request) to the AMF network element, where the session request indicates downlink tunnel information of the RAN (including the IP address of the RAN network element and the downlink tunnel endpoint identifier).

S411: The AMF network element sends a session modification request (eg, a PDU session modification request) to the I-SMF network element, where the session modification request indicates downlink tunnel information of the RAN.

S412: The I-SMF network element and the I-UPF network element perform N4 session creation/modification request and response interaction, and configure downlink tunnel information of the RAN and uplink tunnel information of the UPF network element.

In a possible implementation, the identifier of the uplink tunnel of the I-UPF network element can also be determined by the I-SMF network element or the I-UPF network element and then performed by the I-SMF network element and the I-UPF network element in step S412. The interaction of the N4 session creation/modification request and response is indicated to the other party. In S403, the interaction of the N4 session creation/modification request and response performed by the I-SMF network element and the I-UPF network element may not indicate the I-UPF network element. the uplink tunnel ID.

S413: The I-SMF network element returns a session modification response (eg, a PDU session modification response) to the AMF network element.

As can be seen from the above Figures 3 and 4, the existing GTP-U tunnel is a tunnel between nodes. Therefore, if there are multi-level intermediate UPF network elements between the RAN and UPF network elements corresponding to the PDU session, during the process of creating the PDU session. It is necessary to configure the multi-level intermediate UPF (I-UPF) network elements included between the RAN and the UPF network elements, which will affect the PDU session establishment efficiency, bring higher delay, and affect user experience.

In addition, in the existing UE handover process, a temporary GTP-U tunnel needs to be created to forward downlink data in the handover process. As shown in Figure 5, the I-UPF1 network element serves RAN1, and the I-UPF2 network element serves RAN2 , in the process of the UE switching from RAN1 to RAN2, in order to ensure that the data is not interrupted during the switching process, the downlink data flow will be sent from the UPF network element to the RAN1 through the I-UPF1 network element. At this time, the air interface of the UE has been switched to RAN2. Therefore, RAN1 cannot directly forward downlink data to the UE. The solution of the existing solution is: before the UE switches from RAN1 to RAN2, first create a temporary GTP- U tunnel, then in the handover process, the downlink data received by RAN1 will be sent to RAN2 through the pre-created temporary GTP-U tunnel, through the I-UPF1 network element and the I-UPF2 network element, and then sent to the UE; after the handover is completed After that, delete the created temporary GTP-U tunnel.

Combined with the existing GTP-U tunnel creation mechanism, it can be seen that the temporary GTP-U tunnel created before the UE handover and the temporary GTP-U tunnel deleted after the handover need to be created or configured node by node. If the intermediate UPF network element (as shown in Figure 5) The I-UPF1 network element and the I-UPF2 network element) are managed by different SMF network elements, and the configuration will be more complicated.

In order to solve the problem of session establishment (such as PDU session establishment) or terminal equipment (UE) switching, it is necessary to perform GTP-U on multiple intermediate nodes (such as multiple intermediate UPFs) on the transmission path of application layer packets such as GTP-U packets. The configuration of forwarding rules such as tunnels is complicated. The embodiment of the present application proposes a communication scheme. By improving or expanding the encapsulation format of application layer packets such as GTP-U packets, the Based on the identity of the destination node and/or the identity of one or more intermediate nodes, the indication of the path for transmitting the application layer message between the source node and the destination node is realized, thereby avoiding forwarding rules such as GTP-U tunnels to the intermediate nodes. The signaling and delay overhead brought by the configuration improves the user experience.

In addition, it should be understood that, in the embodiments of the present application, at least one may also be described as one or more, and the multiple may be two, three, four or more, which is not limited in this application. In this embodiment of the present application, "/" may indicate that the objects associated before and after are an "or" relationship, for example, A/B may indicate A or B; "and/or" may be used to describe that there are three types of associated objects A relationship, for example, A and/or B, can mean that A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In order to facilitate the description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, words such as "first" and "second" may be used to distinguish technical features with the same or similar functions. The words "first", "second" and the like do not limit the quantity and execution order, and the words "first", "second" and the like do not limit the difference. In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or illustrations, and any embodiment or design solution described as "exemplary" or "for example" should not be construed are preferred or advantageous over other embodiments or designs. The use of words such as "exemplary" or "such as" is intended to present the relevant concepts in a specific manner to facilitate understanding.

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

FIG. 6 is a schematic diagram of a communication process provided by an embodiment of the present application, and the process includes:

S601: The source node encapsulates a message in an application layer message, and a message header of the application layer message includes an identifier of a destination node of the application layer message.

In this embodiment of the present application, the application layer packet may be a packet carried at Layer 2 (data link layer) or above Layer 3 (network layer), such as GTP-U packets, generic routing encapsulation (generic routing encapsulation, GRE) packets, virtual extensible local area network (VXLAN) packets, etc., the identifier of the destination node can be the IP address of the destination node, media access control (media access control, MAC) address, etc. Wherein, for uplink data transmission of a session (such as a PDU session), the source node may be the first access network device (RAN1), and the destination node may be a UPF network element; for downlink data transmission of a session, the source node may be a UPF network element , the destination node can be RAN1; in addition, in the handover process of the UE, the source node can also be RAN1, and the destination node can also be RAN2, where RAN2 is the access network device that the UE accesses after the handover, and RAN1 is the access network device that the UE accesses before the handover access network equipment.

In addition, for the uplink data transmission or downlink data transmission of the session and the handover process of the UE, the intermediate node located on the path for transmitting the application layer message between the source node and the destination node may be an intermediate user plane function (I-UPF) network. element, which plays the role of forwarding the application layer message sent by the source node to the destination node.

Taking application layer packets as GTP-U packets as an example, in order to avoid configuring forwarding rules such as GTP-U tunnels on intermediate nodes, the encapsulation format of GTP-U packets can be improved or extended. The header of the message implements the indication of the forwarding path for the intermediate node to forward the GTP-U message to the destination node.

Manner 1: As shown in FIG. 7 , a field for carrying the identification of the destination node of the GTP-U packet, such as an identification (Target) field, may be added to the packet header of the GTP-U packet. The intermediate node may determine a forwarding path for forwarding the GTP-U message to the destination node according to the identifier of the destination node included in the header of the GTP-U message.

In a possible implementation, the packet header of the GTP-U packet may also carry the tunnel identifier corresponding to the destination node, such as the tunnel endpoint identifier corresponding to the destination node, which is used to identify the destination node receiving the GTP-U packet. GTP-U tunnel. The tunnel endpoint identifier corresponding to the destination node may be carried by adding other fields to the packet header of the GTP-U packet, for example, by adding a P-TEID field.

Mode 2: As shown in Figure 8, the TEID field in the header of the GTP-U packet can also be extended to the N-TEID field, and the end-to-end tunnel identifier is carried by the N-TEID field, and the end-to-end tunnel identifier is used to identify the end-to-end tunnel. Identify the tunnel through which the destination node receives the GTP-U message from the source node, and each node uses the end-to-end tunnel identifier to identify the GTP-U tunnel on the path for transmitting the GTP-U message between the source node and the destination node.

In a possible implementation, the N-TEID field may be composed of a TEID field and a Target field, where the TEID field is used to carry the tunnel identifier corresponding to the destination node, such as the tunnel endpoint identifier corresponding to the destination node, and the Target field carries the destination node identifier. , such as the IP address of the destination node, etc. The tunnel ID corresponding to the destination node and the ID of the destination node constitute the end-to-end tunnel ID. The intermediate node may determine the forwarding path for forwarding the GTP-U message to the destination node according to the identifier of the destination node in the N-TEID field.

In addition, as shown in (A) and (B) in FIG. 9 , the Target field is added to the header of the GTP-U message or the TEID field in the header of the GTP-U message is extended to the N-TEID field At the same time, a field for carrying transmission path information, such as a UPF list (list) field, may also be added to the packet header of the GTP-U packet. The transmission path information includes the identifiers of one or more intermediate nodes on the path where the GTP-U message is transmitted between the source node and the destination node. or the identifiers of multiple intermediate nodes, to determine the forwarding path for forwarding the GTP-U message to the destination node. The identifier of the intermediate node may be an IP address of the intermediate node, a tunnel identifier corresponding to the intermediate node, and the like. For example, for the uplink data transmission of the session, the tunnel identifier corresponding to the intermediate node may be the uplink tunnel endpoint identifier of the intermediate node.

In a possible implementation, the UPF list field may carry the identifier of the next-hop intermediate node of the source node, or may not carry the identifier of the next-hop intermediate node of the source node. Referring to FIG. 5 , taking the source node as RAN1 and the destination node as RAN2 as an example, I-UPF1 is the next-hop intermediate node of the source node, when RAN1 encapsulates the GTP-U message sent to RAN2, the GTP-U The UPF list field in the header of the message may only carry the identifier of I-UPF2, or may carry both the identifier of I-UPF1 and the identifier of I-UPF2.

It should be understood that the above-mentioned carrying the identifier of the destination node through the Target field, carrying the end-to-end tunnel identifier through the N-TEID field, and carrying the transmission path information through the UPF list field are only examples, and can also be carried through the GTP-U message. Other fields in the packet header carry the identifier of the destination node, the identifier of the end-to-end tunnel, etc., which are not limited in this embodiment of the present application.

As an example, for uplink data transmission or downlink data transmission of a session, the source node may learn the identity of the destination node and one or more intermediate nodes on the path for transmitting the application layer message from the session message from the session management function network element. One or more items of information such as the identifier of the destination node and the tunnel identifier corresponding to the destination node. The session message may be a session creation/modification request (such as an N4 session creation/modification request), a session creation response, etc. It can be understood that the source node of downlink data transmission for a session may be the UPF network element, and the destination node may be RAN1 , the session management function network element can send a session creation/modification request including the identity of RAN1 to the UPF network element; for the uplink data transmission of the session, the source node can be RAN1, the destination node can be the UPF network element, and the session management function network element to the The session creation response sent by RAN1 may also be called other messages when forwarded to RAN1 via other network elements. For example, when forwarded by the access and mobility management function network element to RAN1, it may also be called a session request. It carries the session creation response or carries the information included or indicated in the session creation response, such as the identifier of the UPF network element.

For the handover process of the UE, the source node can obtain the identity of the destination node, the identity of one or more intermediate nodes on the path for transmitting the application layer message, and the tunnel identity corresponding to the destination node from the handover command from the session management function network element. one or more of the information. It can be understood that, for the handover process of the UE, the source node may be RAN1 and the destination node may be RAN2, and the handover command may also be called other messages when forwarded between the session management function network element and other network elements of RAN1, such as by When the access and mobility management function network element forwards it to RAN1, it is called a handover command, and when the session management function network element sends it to the access and mobility management function network element, it can also be called a UE context update response.

As an example, when an application on the UE is started, the UE is triggered to request to create a PDU session, the UE sends a PDU session creation request to the RAN (such as RAN1) to which it accesses, and RAN1 sends the PDU session creation request via the access and the mobility management function network element and other network elements to the session management function network element, the session management function network element selects the UPF network element for the PDU session, and sends the identity of the UPF network element to the access and mobility through the PDU session creation response The management function network element, the access and mobility management function network element sends information such as the PDU session creation response or the UPF network element identifier indicated by the PDU session creation response to the RAN1 through the PDU session request, and the RAN1 learns the uplink of the UE's PDU session. The destination node of the message is the UPF network element, and the identifier of the destination node is the identifier of the UPF network element. When RAN1 receives the uplink packet of the PDU session from the UE, it can encapsulate the uplink packet into a GTP-U packet using the encapsulation format shown in Figure 7 or Figure 8 or Figure 9. The Target field in the packet header carries the identifier of the UPF network element, which is used by the intermediate node to determine the forwarding path for forwarding the GTP-U message to the UPF network element according to the identifier of the UPF network element.

In a possible implementation, the identification of one or more intermediate nodes on the path where the source node transmits the application layer message to the destination node. The source node can also use the routing policy locally configured by the source node (such as a routing table containing the transmission path for the source node to send application-layer packets to each node or device in the network where the source node is located) or the routing policy issued by the session management function network element. , and the identifier of the destination node, determine the path for transmitting the application layer message to the destination node, and then determine the identifiers of one or more intermediate nodes on the path for transmitting the application layer message to the destination node.

In addition, in this embodiment of the present application, a forwarding rule for forwarding to the destination node may also be preconfigured on the intermediate node. Specifically, the forwarding rule may be: when the Target field is the identifier of the destination node, forward the application layer message to the destination node according to the identifier of the destination node.

The forwarding rules for forwarding to RAN1 may be pre-configured on the UPF network element. Specifically, the forwarding rule may be: when the Target field is the identifier of RAN1, forward the application layer packet to the intermediate node located on the path for transmitting the application layer packet between the UPF network element and RAN1.

Similarly, the forwarding rules for forwarding to the UPF network element or RAN2 may be pre-configured on RAN1. The forwarding rule may specifically be: when the Target field is the identifier of the UPF network element, forward the application layer packet to the intermediate node located on the path between the RAN1 network element and the UPF network element on the path for transmitting the application layer packet; the Target field is the RAN2 network element. When the identification is performed, the application layer packet is forwarded to the intermediate node located on the path for transmitting the application layer packet between RAN1 and RAN2.

S602: The source node sends the application layer packet to an intermediate node, and the intermediate node receives the application layer packet.

Wherein, the intermediate node is located on the path for transmitting the application layer message between the source node and the destination node.

Taking the source node as RAN1, the destination node as the UPF network element, and the application layer packet as the GTP-U packet as an example, RAN1 encapsulates the uplink packet from the UE as a GTP-U packet as shown in Figure 7 or Figure 8 or Figure 9. After the U message, RAN1 can send the encapsulated GTP-U message to the next hop node that transmits the GTP-U message, for example, send the encapsulated GTP-U message to the I-UPF network element serving RAN1.

S603: The intermediate node forwards the application layer packet according to the identifier of the destination node.

Still taking the application layer packet as an example of a GTP-U packet, any intermediate node located on the path that transmits the GTP-U packet between the source node and the destination node receives the GTP-U packet from the source node. According to the identifier of the destination node included in the message header of the GTP-U message, determine the next hop node of the GTP-U message to the destination node, and send the GTP-U message to the next hop node. arts. As an example: the intermediate node can use the identifier of the destination node carried in the Target field or the N-TEID field in the header of the GTP-U packet, and the local routing policy (such as including the intermediate node to each node in the network where the intermediate node is located). or the routing table of the transmission path of the GTP-U packet sent by the device) or the routing policy issued by the SMF network element, determine the forwarding path of the GTP-U packet to the destination node, and then determine the destination node of the GTP-U packet. The next hop node for the node to transmit.

In a possible implementation, if the header of the GTP-U message includes the identifiers of one or more intermediate nodes on the path for transmitting the GTP-U message between the source node and the destination node, the middle The node may also determine the next hop node for transmission to the destination node according to the identifiers of the one or more intermediate nodes.

In addition, in order to improve the forwarding efficiency of the GTP-U message and facilitate the intermediate node to quickly know the next hop node, if the identifier of one or more intermediate nodes included in the header of the GTP-U message forwarded by the intermediate node contains its own identification, and the intermediate node can delete its own identification in the identification of the one or more intermediate nodes when forwarding the GTP-U message to the next hop node; or, the intermediate node is in the next hop When forwarding the GTP-U message, the node deletes the identifier of the next hop node in the identifiers of the one or more intermediate nodes.

The above is mainly introduced based on the identification of the destination node to realize the determination of the forwarding path for the intermediate node to forward the application layer message to the destination node. In another possible implementation, it can also be based on the location between the source node and the destination node. The identification of one or more intermediate nodes on the path for transmitting the application layer message between the two nodes realizes the determination of the forwarding path for the intermediate node to forward the application layer message to the destination node.

FIG. 10 is a schematic diagram of a communication process provided by an embodiment of the present application, and the process includes:

S1001: The source node encapsulates the message in an application layer message, and the message header of the application layer message includes the identifiers of one or more intermediate nodes.

Wherein, the one or more intermediate nodes are located on the path for transmitting the application layer message between the source node and the destination node.

Taking the application layer packet as an example of a GTP-U packet, as shown in Figure 11, in order to avoid the configuration of forwarding rules such as GTP-U tunnels on the intermediate node, you can add a message to the packet header of the GTP-U packet. A field used to carry transmission path information, such as the UPF list field. The transmission path information includes the identifiers of one or more intermediate nodes on the path where the GTP-U message is transmitted between the source node and the destination node, so that the intermediate nodes can or the identifiers of multiple intermediate nodes, to determine the forwarding path for forwarding the GTP-U message to the destination node.

In a possible implementation, in order to facilitate the identification of the destination node by the intermediate node, the identification of the destination node may also be carried in the transmission path information, that is, in the header of the GTP-U packet, not only the source node and destination node The identifiers of one or more intermediate nodes on the path where the GTP-U message is transmitted between nodes, as well as the identifiers of the destination nodes.

In another possible implementation, in order to facilitate the intermediate node to identify and determine the destination node and the tunnel through which the destination node receives the GTP-U message, the transmission path information may also carry the tunnel identifier corresponding to the destination node. For example, for uplink data transmission of a session, the tunnel identifier corresponding to the destination node is the uplink tunnel endpoint identifier of the destination node, and the transmission path information carries the uplink tunnel endpoint identifier of the destination node. The intermediate node of the previous hop of the destination node can identify the destination node according to the upstream tunnel endpoint identifier of the destination node, determine the GTP-U tunnel for the destination node to receive the GTP-U message, and forward the GTP-U message to the destination node.

In addition, as shown in (A) and (B) in Figure 9, on the basis of adding the UPF list field to the header of the GTP-U message, Target can also be added to the header of the GTP-U message field or extend the TEID field in the header of the GTP-U message to the N-TEID field. For the description of the UPF list field, the Target field or the N-TEID field, refer to the description in the communication process shown in Figure 6. Let's go into details.

In addition, it should be understood that, as shown in (B) in Figure 9, when the UPF list field is added to the header of the GTP-U message, the Target field in the N-TEID field can not only be the identifier of the destination node, It may also be information such as a global unified identifier, as long as the end-to-end tunnel identifier carried in the N-TEID field is guaranteed to be unique.

In this embodiment of the present application, the forwarding rule for forwarding to the destination node may also be preconfigured on the intermediate node. The specific forwarding rule can be: when the Target field is the identifier of the destination node, the application layer packet is forwarded to the destination node. If the Target field is the global unified identifier instead of the identifier of the destination node, the specific forwarding rule can be: according to the UPF list The transmission path information in the field forwards the application layer packet.

The forwarding rules for forwarding to RAN1 may be pre-configured on the UPF network element. Specifically, the forwarding rule may be: when the Target field is the identifier of RAN1, forward the application layer packet to the intermediate node located on the path between the UPF network element and RAN1 on the path for transmitting the application layer packet; or if the Target field is the global unified identifier, When it is not the identifier of the destination node, the identifier of RAN1 is indicated in the UPF list field while forwarding the application layer message to the intermediate node.

Similarly, the forwarding rules for forwarding to the UPF network element or RAN2 may be pre-configured on RAN1. The forwarding rule may specifically be: when the Target field is the identifier of the UPF network element, forward the application layer packet to the intermediate node located on the path between the RAN1 network element and the UPF network element on the path for transmitting the application layer packet; the Target field is the RAN2 network element. When the identification is performed, the application layer packet is forwarded to the intermediate node located on the path for transmitting the application layer packet between RAN1 and RAN2. Or if the Target field is a global unified identifier instead of the identifier of the destination node, the identifier of the destination node (UPF network element or RAN2) is indicated in the UPF list field while forwarding the application layer message to the intermediate node.

S1002: The source node sends the application layer packet to an intermediate node, and the intermediate node receives the application layer packet.

S1003: The intermediate node forwards the application layer packet according to the identifiers of the one or more intermediate nodes.

Specifically, for the implementation of the intermediate node forwarding the application layer message according to the identifiers of the one or more intermediate nodes, reference may be made to the description in the communication process shown in FIG. 6 , which will not be repeated.

Still taking the application layer message as an example of a GTP-U message, the following describes the GTP-U message transmission and the tunnel configuration process for GTP-U message transmission in conjunction with part of the PDU session creation or UE handover process.

Scenario 1: PDU session, taking the encapsulation format shown in (B) in Figure 9 as an example for GTP-U packets, as shown in Figure 12, for the uplink data transmission of the PDU session, the source node is RAN1 and the destination node is UPF The intermediate node between the network element, RAN1 and UPF network element is the I-UPF network element; for the downlink data transmission of the PDU session, the source node is the UPF network element, and the destination node is RAN1, the intermediate node between the UPF network element and RAN1 The node is an I-UPF network element. It is assumed that the I-UPF network element is managed by the I-SMF network element, and the UPF network element is managed by the SMF network element.

As shown in Figure 13, it is an example of a PDU session creation process, which includes:

S1301: RAN1 forwards a session creation request (eg, a PDU session creation request) from the UE to the AMF network element.

S1302: The AMF network element forwards the session creation request to the selected I-SMF network element.

S1303: The I-SMF network element forwards the session creation request to the SMF network element.

In a possible implementation, the I-SMF network element may further indicate the identifier of the I-UPF network element selected by the I-SMF network element in the forwarded session creation request, such as the IP address of the I-UPF network element.

S1304: The SMF network element and the selected UPF network element perform an N4 session creation/modification request and response interaction, and configure a first end-to-end tunnel endpoint identifier (N-TEID1).

The N-TEID1 is used to identify the tunnel through which the UPF network element receives the GTP-U message from the RAN1, and is used for the UPF network element to receive the GTP-U message from the RAN1.

Specifically, after receiving the session creation request, the SMF network element selects the UPF network element. If the SMF network element allocates N-TEID1 to the UPF network element, the SMF network element indicates the N-TEID1 in the N4 session creation/modification request sent to the UPF network element; if the UPF network element allocates N-TEID1, then The UPF network element will indicate the N-TEID1 in the N4 session creation/modification response sent to the SMF network element.

S1305: The SMF network element sends a session creation response (eg, a PDU session creation response) to the I-SMF network element, and indicates the N-TEID1 in the session creation response.

In a possible implementation, if the Target field in N-TEID1 is a global unified identifier (eg, global unified identifier 1), rather than the identifier of a UPF network element, the session creation response may also indicate that the UPF network ID of the element, such as the IP address of the UPF network element.

S1306: The I-SMF network element sends the session establishment response to the AMF network element, where the session establishment response indicates the N-TEID1.

In a possible implementation, if the Target field in N-TEID1 is a global unified identifier instead of the identifier of the UPF network element, the identifier of the UPF may also be indicated in the session creation response; or the identifier of the UPF may be indicated in the session creation response; The transmission path information is indicated in the creation response, and the transmission path information includes the identifier of the UPF network element, and may also include the identifier of the I-UPF network element.

In addition, if you need to configure a policy related to the N-TEID1 session, the I-SMF network element can also send the session policy to the I-UPF network element. .

S1307: The SMF network element sends a session request (eg, a PDU session request) to the RAN1, where the N-TEID1 is indicated in the session request.

S1308: The RAN1 allocates a second end-to-end tunnel identifier (N-TEID2).

The N-TEID2 is used to identify the tunnel through which the RAN1 receives the GTP-U message from the UPF network element, and is used for the RAN1 to receive the GTP-U message from the UPF network element.

S1309: The RAN1 sends a session request (eg, a PDU session request) to the AMF network element, and indicates the N-TEID2 in the session request.

In a possible implementation, if the Target field in N-TEID2 is a global unified identifier (such as global unified identifier 2), not the identifier of RAN1, the identifier of RAN1 may also be indicated in the session request, Such as the IP address of RAN1.

S1310: The AMF network element sends a session modification request (eg, a PDU session modification request) to the I-SMF network element, where the session modification request indicates the N-TEID2.

In a possible implementation, if the N-TEID2 session-related policy needs to be configured, the I-SMF network element can also send the session policy to the I-UPF network element, such as configuring the identification of GTP-U through N-TEID2 in the session policy The session corresponding to the message, etc.

S1311: The I-SMF network element forwards the session modification request to the SMF network element, where the session modification request indicates the N-TEID2.

In a possible implementation, if the Target field in the N-TEID2 is a global unified identifier instead of the identifier of RAN1, the identifier of RAN1 may also be indicated in the session modification request. In addition, if the identifier of the I-UPF network element is not indicated in step S1303, the identifier of the I-UPF network element may also be indicated in the session modification request.

S1312: Perform N4 session modification request/response interaction between the SMF network element and the UPF network element, and configure the N-TEID2.

In a possible implementation, if the Target field in N-TEID2 is a global unified identifier instead of the identifier of RAN1, the SMF network element may also send transmission path information to the UPF network element, where the transmission path information includes all The identifier of the RAN1 may also include the identifier of the I-UPF network element.

In addition, in this embodiment of the present application, the forwarding rule for forwarding to the UPF network element/RAN1 may also be preconfigured on the I-UPF network element. The forwarding rule may specifically be: when the Target field is the identifier of the UPF network element, forward the GTP-U message to the UPF network element; when the Target field is RAN1, forward the GTP-U message to RAN1. Or if the Target field is a global unified identifier rather than the identifier of the destination node, the forwarding rule may specifically be: forward the GTP-U message according to the transmission path information in the UPF list field.

The forwarding rules for forwarding to RAN1 may be pre-configured on the UPF network element. The forwarding rule may specifically be: when the Target field is the identifier of RAN1, forward the GTP-U packet to the I-UPF network element; or if the Target field is the global unified identifier rather than the identifier of the destination node, forward the GTP-U packet to the I-UPF network element The GTP-U message is forwarded, and the identifier of RAN1 is indicated in the UPF list field.

Similarly, the forwarding rule for forwarding to the UPF network element may be pre-configured on RAN1. Specifically, the forwarding rule may be: when the Target field is the identifier of the UPF network element, forward the GTP-U packet to the I-UPF network element; or if the Target field is the global unified identifier instead of the identifier of the destination node, forward the GTP-U packet to the I-UPF network element. The network element forwards the GTP-U message, and the UPF list field indicates the identifier of the UPF network element.

As can be seen from the above Figures 12 and 13, by using the end-to-end tunnel identifiers (such as N-TEID1 and N-TEID2) on the path for transmitting GTP-U packets between RAN1 and UPF network elements, the intermediate UPF network elements are It is not necessary to configure the forwarding rules of session granularity, and the forwarding path can be determined based on the identifier of the destination node or the transmission path information in the header of the GTP-U packet.

It should be understood that the above-mentioned PDU session creation process is illustrated by taking the different uplink and downlink end-to-end tunnel endpoint identifiers as an example, and if the uplink and downlink end-to-end tunnel endpoint identifiers are the same, only the uplink is executed. Or the downlink tunnel creation process is sufficient, that is, only the configuration process of the above N-TEID1 or N-TEID2 may be performed.

Scenario 2: UE switching scenario.

As shown in Figure 14, the UE switches from RAN1 to RAN2, and RAN1 communicates with the I-UPF1 network element, and RAN2 communicates with the I-UPF2 network element. Therefore, after the UE is handed over, the I-UPF1 network element will also be handed over to the I-UPF2 network. After the handover, the AMF1 network element that manages RAN1 will also be switched to the AMF2 network element that manages RAN2. To simplify the process, it is assumed that the I-UPF1 network element, the I-UPF2 network element and the UPU network element are all managed by the SMF network element.

As shown in Figure 15, it is an example of the UE handover process, and the process includes:

S1501: RAN1 initiates a UE handover (handover) request to the AMF1 network element, including the identifier of RAN2.

S1502: The core network element selects the I-UPF2 network element, and creates an uplink GTP-U tunnel from the RAN2 to the UPF network element.

For the process of creating the uplink GTP-U tunnel from RAN2 to the UPF network element, reference may be made to the process of creating the uplink GTP-U tunnel from RAN1 to the UPF network element in FIG. 13 , which will not be repeated. The information of the uplink GTP-U tunnel, such as the end-to-end tunnel identifier and transmission path information for uplink data transmission from RAN2 to the UPF network element, will be sent to RAN2.

S1503: RAN2 allocates a third end-to-end tunnel identifier (N-TEID3).

S1504: The RAN2 sends a handover response (handover response) to the AMF2 network element, and the handover response indicates the N-TEID3.

In a possible implementation, if the Target field in N-TEID3 is a global unified identifier (such as global unified identifier 3), rather than the identifier of RAN2, the identifier of RAN2 may also be indicated in the handover response, Such as the IP address of RAN2.

S1505: The AMF2 network element sends a UE context update request to the SMF network element, where the UE context update request indicates the N-TEID3.

In a possible implementation, if the Target field in N-TEID3 is a global unified identifier instead of the identifier of RAN2, the identifier of RAN2 may also be indicated in the UE context update request, such as the IP address of RAN2 .

S1506: The SMF network element sends a UE context update response to the AMF2 network element, where the UE context update response indicates the N-TEID3.

In a possible implementation, if the Target field in N-TEID3 is a global unified identifier instead of the identifier of RAN2, the identifier of RAN2 may also be indicated in the UE context update response, such as the IP address of RAN2 .

In addition, the SMF network element can also determine the transmission path information of the downlink data from RAN1 to RAN2 during the UE handover process, for example, from RAN1 to I-UPF1 network element, from I-UPF1 network element to I-UPF2 network element, and then from I-UPF1 network element to I-UPF2 network element. UPF2 NE to RAN2 NE. The SMF network element may further indicate the transmission path information in the UE context update response.

S1507: The AMF2 network element sends a UE context creation response to the AMF1 network element, where the UE context creation response carries the UE context update response or carries information included in the UE context update response, such as N- TEID3.

After step S1507 is completed, the preparation process for the handover of the UE is completed.

S1508: The AMF1 network element sends a handover command (handover command) to the RAN1, and the handover command indicates the N-TEID3.

It should be understood that the information indicated by the handover command in S1508 includes the information indicated by the UE context update response in S1506. If the UE context update response also indicates the identity of RAN2, transmission path information, etc., it is also indicated in the handover command in S1508. The identity of the RAN2, transmission path information, etc. indicated by the UE context update response.

S1509: When RAN1 receives the GTP-U message from the UPF network element, it forwards the GTP-U message to RAN2.

Specifically, RAN1 can determine the identity of RAN2 according to the Target information in N-TEID3. If the Target is a global unified identity, then determine the identity of RAN2 according to the indicated identity of RAN2 or the identity of the destination node in the transmission path information, and then according to the forwarding policy (local configuration or SMF network element pre-configuration), determine to send the GTP-U message to the I-UPF1 network element first. RAN1 encapsulates the identifier of RAN2 (in the Target field or the UPF list field) in the forwarded GTP-U message, and optionally encapsulates the identifier of I-UPF2 in the UPF list field (optionally in the UPF list field in this case). The identification of the package I-UPF1 in the middle).

S1510: After the I-UPF1 network element receives the GTP-U message from RAN1, according to the identifier of RAN2 in the header of the GTP-U message and the local forwarding policy (locally configured or pre-configured by the SMF network element) ), forward the GTP-U message to the I-UPF2 network element, or forward the message to the I-UPF2 network element according to the transmission path information in the GTP-U message. Afterwards, the I-UPF2 network element forwards the GTP-U message to the RAN2 in a similar manner.

S1511: The UE completes the handover process and releases the resources related to the original session on the RAN1 and the UPF network element.

In another possible implementation, during the handover preparation process of the UE, the SMF network element can directly configure the transmission path information from RAN1 to RAN2 to RAN1, and when RAN1 receives the GTP-U message from the UPF network element, the When forwarding GTP-U packets, encapsulate the transmission path information from RAN1 to RAN2 in the forwarded GTP-U packets, so as to avoid intermediate UPF network elements (such as I-UPF1 network elements, I-UPF2 network elements), etc. Configuration of the mapping relationship of session granular GTP-U tunnels. As an example, referring to FIG. 5 , the SMF network element may create temporary GTP-U tunnels from RAN1 to I-UPF1 network element, from I-UPF1 network element to I-UPF2 network element, and from I-UPF2 network element to RAN2. After that, the identifier TEID4 of the I-UPF1 network element, the identifier TEID5 of the I-UPF2 network element, and the identifier TEID6 of the RAN2 are sent to RAN1 as transmission path information, which are used to identify the forwarding of the GTP-U message from the UPF network element by RAN1 path of.

The solution provided by the present application has been introduced above mainly from the perspective of interaction between the source node and the intermediate node. It can be understood that, in order to realize the above functions, each network element includes a corresponding hardware structure and/or software module (or unit) for performing each function. Those skilled in the art should easily realize that the present application can be implemented in hardware or a combination of hardware and computer software with the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein. Whether a function is performed by hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

FIG. 16 and FIG. 17 are schematic structural diagrams of possible communication apparatuses provided by embodiments of the present application. These communication apparatuses can be used to implement the functions of the source node or the intermediate node in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In this embodiment of the present application, the communication device may be the source node in FIG. 6 or FIG. 10 , the intermediate node in FIG. 6 or FIG. 10 , or the module applied to the source node or the intermediate node (such as chip).

As shown in Figure 16. The communication apparatus 1600 may include: a processing unit 1602 and a communication unit 1603, and may also include a storage unit 1601. The communication apparatus 1600 is configured to implement the function of the source node or the intermediate node in the method embodiment shown in FIG. 6 or FIG. 10 .

In a possible design, the processing unit 1602 is used to implement corresponding processing functions. The communication unit 1603 is used to support the communication between the communication device 1600 and other network entities. The storage unit 1601 is used to store program codes and/or data of the communication device 1600 . Optionally, the communication unit 1603 may include a receiving unit and/or a sending unit for performing receiving and sending operations, respectively.

When the communication apparatus 1600 is configured to implement the function of the source node in the method embodiment: the processing unit 1602 is configured to encapsulate the packet in an application layer packet, where the packet header of the application layer packet includes the application layer packet The identifier of the destination node of the message; the communication unit 1603 is configured to send the application layer message to a first intermediate node, where the first intermediate node is located between the communication device and the destination node to transmit the application layer on the path of the message.

In a possible design, the packet header of the application layer packet includes the tunnel identifier corresponding to the destination node.

In a possible design, the tunnel identification includes the identification of the destination node.

In a possible design, the communication unit 1603 is further configured to receive a session message from the session management function network element, where the session message includes the identifier of the destination node; or, receive a session management function network element from the session management function network element. a handover command, where the handover command includes the identifier of the destination node.

In a possible design, the communication device is a first access network device, and the destination node is a user plane function network element; or, the communication device is a user plane function network element, and the destination node is the first network element. an access network device; or, the communication device is a first access network device, and the destination node is a second access network device.

In a possible design, the application layer message is a GTP-U message.

In another possible implementation, the processing unit 1602 is configured to encapsulate the packet in an application-layer packet, where the packet header of the application-layer packet includes identifiers of one or more intermediate nodes, the one or multiple intermediate nodes are located on the path for transmitting the application layer packet between the communication device and the destination node; the communication unit 1603 is configured to send the application layer packet to the first intermediate node, the first intermediate node The node is located on the path for transmitting the application layer message between the communication device and the destination node.

In one possible design, the one or more intermediate nodes include the first intermediate node.

In a possible design, the communication unit 1603 is further configured to receive a session message from the session management function network element, where the session message includes the identifiers of the one or more intermediate nodes; or, receive a session message from the network element of the session management function. A handover command for the session management function network element, the handover command including the identifiers of the one or more intermediate nodes.

In a possible design, the application layer message is a GTP-U message.

When the communication apparatus 1600 is used to implement the function of the intermediate node in the method embodiment:

The communication unit 1603 is configured to receive an application layer packet from the source node, the packet header of the application layer packet includes the identifier of the destination node of the application layer packet; the processing unit 1602 is configured to, according to the purpose The identifier of the node, which forwards the application layer message.

In a possible design, when forwarding the application layer packet according to the identifier of the destination node, the processing unit 1602 is specifically configured to obtain the destination node of the application layer packet to the destination node according to the identifier of the destination node. The next hop node transmitted by the destination node; the communication unit 1603 is further configured to send the application layer packet to the next hop node.

In a possible design, the application layer message is a GTP-U message.

In another possible implementation, the communication unit 1603 is configured to receive an application layer packet from the source node, where the packet header of the application layer packet includes identifiers of one or more intermediate nodes, the one or more Multiple intermediate nodes are located on the path for transmitting the application layer message between the source node and the destination node; the processing unit 1602 is configured to forward the application layer packet according to the identifiers of the one or more intermediate nodes message.

In a possible design, when forwarding the application layer packet according to the identifiers of the one or more intermediate nodes, the processing unit 1602 is specifically configured to obtain, according to the identifiers of the one or more intermediate nodes, the The next hop node for transmitting the application layer message to the destination node; the communication unit 1603 is further configured to send the application layer message to the next hop node.

In a possible design, the processing unit 1602 is further configured to delete the identification of the communication device in the identification of the one or more intermediate nodes, or delete the identification of the one or more intermediate nodes. The identity of the next hop node of the communication device.

In a possible design, the application layer message is a GTP-U message.

More detailed descriptions about the above-mentioned processing unit 1602 and the communication unit 1603 can be obtained directly by referring to the relevant descriptions in the method embodiments shown in FIG. 6 or FIG. 10 , and details are not repeated here.

As shown in FIG. 17 , the communication device 1700 includes a processor 1710 and an interface circuit 1720 . The processor 1710 and the interface circuit 1720 are coupled to each other. It can be understood that the interface circuit 1720 can be a transceiver or an input-output interface. Optionally, the communication device 1700 may further include a memory 1730 for storing instructions executed by the processor 1710 or input data required by the processor 1710 to execute the instructions or data generated after the processor 1710 executes the instructions.

When the communication device 1700 is used to implement the communication method shown in FIG. 6 or FIG. 10 , the processor 1710 is used to implement the function of the above-mentioned processing unit 1602 , and the interface circuit 1720 is used to implement the function of the above-mentioned communication unit 1603 .

As another form of this embodiment, a computer-readable storage medium is provided, on which instructions are stored, and when the instructions are executed, the communication methods applicable to the source node or the intermediate node in the above method embodiments can be executed.

As another form of this embodiment, a computer program product containing instructions is provided, and when the instructions are executed, the communication method applicable to the source node or the intermediate node in the above method embodiments can be executed.

As another form of this embodiment, a chip is provided, and when the chip is running, the communication method applicable to the source node or the intermediate node in the above method embodiments can be executed.

As will be appreciated by those skilled in the art, the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It will be understood that each flow and/or block in the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce Means for implementing the functions specified in a flow or flow of a flowchart and/or a block or blocks of a block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions The apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

These computer program instructions can also be loaded on a computer or other programmable data processing device to cause a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process such that The instructions provide steps for implementing the functions specified in the flow or blocks of the flowcharts and/or the block or blocks of the block diagrams.

While the preferred embodiments of the present application have been described, additional changes and modifications to these embodiments may occur to those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be construed to include the preferred embodiment and all changes and modifications that fall within the scope of this application.

Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

A communication method, comprising:

The source node encapsulates the message in an application layer message, and the header of the application layer message includes the identifier of the destination node of the application layer message;

The source node sends the application layer message to a first intermediate node, where the first intermediate node is located on a path for transmitting the application layer message between the source node and the destination node.
The method according to claim 1, wherein a packet header of the application layer packet includes a tunnel identifier corresponding to the destination node.
The method of claim 2, wherein the tunnel identifier includes an identifier of the destination node.
The method according to any one of claims 1-3, wherein the method further comprises:

the source node receives a session message from a session management function network element, where the session message includes the identifier of the destination node; or,

The source node receives a handover command from the session management function network element, and the handover command includes the identifier of the destination node.
The method according to any one of claims 1-4, wherein the source node is a first access network device, and the destination node is a user plane function network element; or,

The source node is a user plane functional network element, and the destination node is a first access network device; or,

The source node is a first access network device, and the destination node is a second access network device.
The method according to any one of claims 1-5, wherein the application layer message is a general packet radio service tunneling protocol user plane GTP-U message.
A communication method, comprising:

The source node encapsulates the message in an application layer message, and the header of the application layer message includes the identifiers of one or more intermediate nodes, and the one or more intermediate nodes are located at the source node and the destination node. on the path for transmitting the application layer message between them;

The source node sends the application layer packet to a first intermediate node, and the first intermediate node is located on a path for transmitting the application layer packet between the source node and the destination node.
8. The method of claim 7, wherein the one or more intermediate nodes comprise the first intermediate node.
The method according to claim 7 or 8, wherein the packet header of the application layer packet further includes a tunnel identifier corresponding to the destination node.
The method according to any one of claims 7-9, wherein the method further comprises:

the source node receives a session message from the session management function network element, the session message includes the identifiers of the one or more intermediate nodes; or,

The source node receives a handover command from the session management function network element, the handover command including the identification of the one or more intermediate nodes.
The method according to any one of claims 7-10, wherein the source node is a first access network device, and the destination node is a user plane function network element; or,

The source node is a user plane functional network element, and the destination node is a first access network device; or,

The source node is a first access network device, and the destination node is a second access network device.
The method according to any one of claims 7-11, wherein the application layer message is a general packet radio service tunneling protocol user plane GTP-U message.
A communication method, comprising:

The first intermediate node receives the application layer message from the source node, and the message header of the application layer message includes the identifier of the destination node of the application layer message;

The first intermediate node forwards the application layer message according to the identifier of the destination node.
The method of claim 13, wherein a packet header of the application layer packet includes a tunnel identifier corresponding to the destination node.
The method of claim 14, wherein the tunnel identification includes an identification of the destination node.
The method according to any one of claims 13-15, wherein the first intermediate node forwards the application layer packet according to the identifier of the destination node, comprising:

The first intermediate node obtains, according to the identifier of the destination node, a next hop node for transmitting the application layer message to the destination node;

The first intermediate node sends the application layer message to the next hop node.
The method according to any one of claims 13-16, wherein the source node is a first access network device, and the destination node is a user plane function network element; or,

The source node is a user plane functional network element, and the destination node is a first access network device; or,

The source node is a first access network device, and the destination node is a second access network device.
The method according to any one of claims 13-17, wherein the application layer message is a general packet radio service tunneling protocol user plane GTP-U message.
A communication method, comprising:

The first intermediate node receives an application layer packet from the source node, the packet header of the application layer packet includes the identifiers of one or more intermediate nodes, and the one or more intermediate nodes are located between the source node and the destination node. on the path for transmitting the application layer message between nodes;

The first intermediate node forwards the application layer packet according to the identifiers of the one or more intermediate nodes.
The method of claim 19, wherein the packet header of the application layer packet further includes a tunnel identifier corresponding to the destination node.
The method according to claim 19 or 20, wherein the first intermediate node forwards the application layer packet according to the identifiers of the one or more intermediate nodes, comprising:

The first intermediate node acquires, according to the identifiers of the one or more intermediate nodes, a next-hop node for transmitting the application layer message to the destination node;

The first intermediate node sends the application layer message to the next hop node.
The method of any one of claims 19-21, wherein the method further comprises:

The first intermediate node deletes the identification of the first intermediate node in the identification of the one or more intermediate nodes, or deletes the next hop of the first intermediate node in the identification of the one or more intermediate nodes The ID of the node.
The method according to any one of claims 19-22, wherein the source node is a first access network device, and the destination node is a user plane function network element; or,

The source node is a user plane functional network element, and the destination node is a first access network device; or,

The source node is a first access network device, and the destination node is a second access network device.
The method according to any one of claims 19-23, wherein the application layer message is a general packet radio service tunneling protocol user plane GTP-U message.
A source node, characterized in that it includes:

communication unit for receiving and sending data;

A processing unit, configured to implement the method of any one of claims 1-12 through the communication unit.
A first intermediate node, comprising:

communication unit for receiving and sending data;

A processing unit, configured to implement the method according to any one of claims 13-24 through the communication unit.
A communication system, comprising:

A source node for implementing the method according to any one of claims 1-12;

A first intermediate node for implementing the method of any one of claims 13-24.
A computer-readable storage medium, characterized in that, a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a computer, the computer is made to execute any one of claims 1-24. the method described.
A computer program, characterized in that, when the computer program is run on a computer, the computer is caused to perform the method according to any one of claims 1-24.
A chip, characterized in that, the chip is used to read a computer program stored in a memory, and execute the method according to any one of claims 1-24.