Packet loss optimization method applied to 5G system UPF, related device and communication system

Abstract

The invention relates to the technical field of communication, and discloses a packet loss optimization method applied to a 5G system UPF, a related device and a communication system, under the condition that a communication session is established between user equipment and a proxy call server, a target message to be transmitted between the user equipment and the proxy call server is obtained, a network communication address of the target message is analyzed, and the target message is transmitted to the proxy call server. And obtaining target address information corresponding to the target address information. A user plane function network element UPF pre-stores server address information sent by a session management device SMF, the user plane function network element UPF performs verification based on the pre-stored server address information and target address information corresponding to a target message, if the pre-stored server address information and the target address information are consistent, the target message is transmitted, and if the pre-stored server address information is consistent with the target address information corresponding to the target message, the user plane function network element UPF transmits the target message. The identification efficiency and accuracy of related messages are improved, the packet loss problem of the messages when the load of a user plane function network element is relatively high is avoided, and the success rate of key service data transmission and the user experience effect are improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a packet loss optimization method, related devices and communication system applied to UPF of a 5G system. Background Art

[0002] In the fifth generation communication system (5G), UPF (User Plane Function) is the actual forwarding point of user data flow, which is used to handle data forwarding in the user plane. When UPF is under high load, it may cause problems such as packet loss and increased latency, affecting user experience and service quality.

[0003] In order to solve the above problems, UPF can selectively discard data packets of low priority or non-critical services to ensure the quality of critical services and reduce its own load. However, in this process, some important critical signaling will also be mistakenly identified as ordinary data streams by UPF and thus discarded by UPF, which will cause data transmission at the user service level to be damaged and the continuity of user service data transmission and user experience cannot be guaranteed. Summary of the invention

[0004] In response to the above problems, the present application provides a packet loss optimization method and related devices applied to the UPF of a 5G system, which improves the success rate of key business data transmission and user experience.

[0005] In order to achieve the above objectives, this application provides the following technical solutions: A packet loss optimization method applied to a 5G system UPF, applied to a user plane function network element UPF, the method comprising: When the user equipment establishes a communication session with the proxy call session server, obtaining a target message to be transmitted between the user equipment and the proxy call session server; If the load of the UPF is higher than the target load threshold, the network communication address of the target message is parsed to obtain the target address information corresponding to the target message; If the target address information corresponding to the target message is consistent with the server address information pre-stored in the UPF, the target message is transmitted.

[0006] Optionally, the method further comprises: If the target address information corresponding to the target message is inconsistent with the server address information pre-stored in the UPF, determining the priority of the target message; If the priority of the target message is lower than the target priority, the target message is discarded and the target message is not transmitted.

[0007] Optionally, if the target address information corresponding to the target message is consistent with the server address information pre-stored in the UPF, transmitting the target message includes: In the case where the target message is an uplink message sent by the user equipment, if the target address information of the uplink message is consistent with the server address information pre-stored by the UPF, the uplink message is transmitted to the data network, and the target address information represents the destination address information of the uplink message; When the target message is a downlink message sent by the proxy call session server to the user equipment, and the target address information represents the source address information of the downlink message, if the source address information corresponding to the downlink message is consistent with the server address information pre-stored in the UPF, the downlink message is forwarded to the user equipment.

[0008] Optionally, the method further comprises: When the user equipment sends a request message for creating a data session with the proxy call session server to the session management device SMF, the response message for creating the data session sent by the SMF is received, and the server address information corresponding to the proxy call session server carried in the response message is stored.

[0009] A packet loss optimization method applied to a 5G system UPF, applied to a session management device SMF, the method comprising: receiving a request message from a user device to establish a data session with a proxy call session server; Determine the server address information corresponding to the proxy call session server based on the configuration information of the session management device SMF itself; Sending a request message carrying server address information corresponding to the proxy call session server to a user plane function network element UPF; In response to receiving a response message indicating successful creation of the data session sent by the UPF, a response message carrying server address information corresponding to the proxy call session server is sent to the user equipment to establish a data session between the user equipment and the proxy call session server.

[0010] A user plane functional network element, comprising: A first acquisition unit, configured to acquire a target message to be transmitted between the user equipment and the proxy call session server when the user equipment establishes a communication session with the proxy call session server; A first parsing unit, configured to parse the network communication address of the target message to obtain target address information corresponding to the target message if the load of the user plane functional network element is higher than a target load threshold; A transmission unit is used to transmit the target message if the target address information corresponding to the target message is consistent with the server address information pre-stored in the user plane function network element.

[0011] Optionally, the user plane function network element further includes: A first determining unit, configured to determine the priority of the target message if the target address information corresponding to the target message is inconsistent with the server address information pre-stored in the user plane function network element; A message discarding processing unit, configured to discard the target message and not transmit the target message if the priority of the target message is lower than the target priority; The storage unit is used to receive response information for creating a data session sent by the SMF when the user equipment sends request information for creating a data session with the proxy call session server to the session management device SMF, and store the server address information corresponding to the proxy call session server carried in the response information.

[0012] Optionally, the transmission unit includes: A first transmission subunit, configured to transmit the uplink message to a data network if the target message is an uplink message sent by a user equipment and if the target address information of the uplink message is consistent with the server address information pre-stored in the user plane functional network element, the target address information representing the destination address information of the uplink message; The second transmission subunit is configured to forward the downlink message to the user equipment if the target message is a downlink message sent by the proxy call session server to the user equipment and the target address information represents the source address information of the downlink message and if the source address information corresponding to the downlink message is consistent with the server address information pre-stored in the user plane function network element.

[0013] A session management device, comprising: A second receiving unit, configured to receive request information from a user equipment to establish a data session with a proxy call session server; A second determining unit, configured to determine server address information corresponding to the proxy call session server based on the configuration information of the session management device itself; A first sending unit, configured to send a request message carrying server address information corresponding to the proxy call session server to a user plane function network element UPF; The second sending unit is used to send a response message carrying the server address information corresponding to the proxy call session server to the user equipment in response to receiving the response message of successful data session creation sent by the UPF, so as to establish a data session between the user equipment and the proxy call session server.

[0014] A communication system, comprising: The user plane function network element as described in any one of the above, the session management device as described in the above, and the user equipment; wherein the user equipment establishes a communication connection with a proxy call session server based on the user plane function network element and the session management device.

[0015] Compared with the prior art, the present application provides a packet loss optimization method, related devices and communication system applied to the UPF of a 5G system. When a communication session is established between a user device and a proxy call server, the target message to be transmitted between the user device and the proxy call server is obtained, and the network communication address of the target message is parsed to obtain the corresponding target address information. The user plane function network element UPF will pre-store the server address information sent by the session management device SMF. The user plane function network element UPF will verify the target address information corresponding to the target message based on the pre-stored server address information. If the two are consistent, the target message will be transmitted to improve the recognition efficiency and accuracy of the relevant messages, avoid the packet loss problem of the message when the user plane function network element is highly loaded, and achieve the improvement of the success rate of key business data transmission and user experience effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0017] Figure 1 A schematic diagram of a 5G architecture provided in an embodiment of the present application; Figure 2 A flowchart of a packet loss optimization method applied to a 5G system UPF provided in an embodiment of the present application; Figure 3 A schematic diagram of a P-CSCF server address IE format provided in an embodiment of the present application; Figure 4 A schematic diagram of a session creation process provided in an embodiment of the present application; Figure 5 A schematic diagram of a processing flow of uplink SIP message identification provided in an embodiment of the present application; Figure 6 A schematic diagram of a processing flow for downstream SIP message identification provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] The terms "first" and "second" in this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may include steps or units that are not listed.

[0020] In an embodiment of the present application, a packet loss optimization method applied to a 5G system UPF is provided. The method is applied to a fifth-generation communication system (5G), so that a user plane functional network element can quickly identify specific messages interacting between a user device and a proxy call server from a massive amount of messages, thereby avoiding the packet loss problem of the specific message and improving the success rate of service data transmission.

[0021] See also Figure 1 , which is a schematic diagram of a 5G architecture provided in an embodiment of the present application. Figure 1The 5G architecture shown includes an access management function (AMF), a session management function (SMF), and a user plane function (UPF). The user plane connection is from UE (User Equipment) to (R)AN ((Radio) Access Network) to UPF to DN (Data Network), and the control plane connection is from UE to AMF to SMF. The control plane and the user plane are separate architectures. UPF interacts with SMF through the N4 interface and is directly controlled and managed by SMF. It processes service flows according to various policies issued by SMF. The user plane message of the N3 interface is encapsulated using the General Packet Radio Service Tunnelling Protocol User Plane (GTP-U) protocol. GTP-U is encapsulated using the User Datagram Protocol (UDP) protocol. The IP message header to which GTP-U belongs carries the source Internet Protocol (IP) address and the destination IP address. Based on IP routing, messages are transmitted between the (R)AN and the UPF, thereby forming a transmission channel between the (R)AN and the UPF.

[0022] IMS (IP Multimedia Subsystem) is a multimedia communication system architecture based on IP network, which provides various multimedia services such as voice, video, data and real-time communication. The IMS system includes network elements such as Serving CSCF (Call Session Control Function, S-CSCF), Interrogating CSCF (I-CSCF), Proxy CSCF (P-CSCF), Home Subscriber Server (HSS), etc. As the entry point of the IMS network, P-CSCF is responsible for interacting with UE, processing SIP signaling, and forwarding requests to the appropriate CSCF.

[0023] In the 5G network, the 5G core network needs to provide the P-CSCF server address for the UE to support IMS services. According to the 3GPP specification, the SMF receives the session establishment request message sent by the UE and carries the P-CSCF server address in the session establishment response message sent to the UE. Subsequently, the UE communicates with the P-CSCF through the SIP (Session Initiation Protocol) protocol, through the user plane data transmission channel, and through the forwarding of (R)AN and UPF to establish and manage IMS services.

[0024] When the UPF is in a high-load state, the UPF can selectively discard data packets of low-priority or non-critical services to ensure the quality of critical services and reduce its own load. For IMS services, the SIP signaling exchanged between the UE and the P-CSCF is the key signaling to control UE voice, video calls and other functions. These signalings are essential for the normal operation of IMS services. Usually for UPF, SIP signaling is regarded as an ordinary data stream, but if the UPF mistakenly discards these IMS service control signalings, it will have a serious impact on the IMS service, for example, it may cause the UE to be unable to make calls, answer calls or hang up calls. Therefore, in an embodiment of the present application, a packet loss optimization method applied to the UPF of a 5G system is provided, which can prevent the UPF from discarding the corresponding IMS service control signaling or related messages. Among them, IMS (IP Multimedia Subsystem, IP Multimedia Subsystem) is a form of multimedia service based on an IP network, which aims to provide terminal customers with a more novel and diverse multimedia service experience through an IP network. SIP (Session Initiation Protocol) is a signaling protocol used to control multimedia communication sessions, such as voice and video calls, multimedia conferences, and other interactive communications. SIP is defined by IETF (Internet Engineering Task Force). It is based on a request / response model, uses HTTP-like syntax, and uses TCP or UDP as a transport layer protocol. P-CSCF can be called a proxy call session server, which is responsible for maintaining the security association between the UE and P-CSCF and applying integrity and confidentiality protection for SIP signaling.

[0025] See also Figure 2 , is a flow chart of a packet loss optimization method applied to a 5G system UPF provided in an embodiment of the present application. The method is applied to a user plane function network element UPF. Specifically, the method may include the following steps: S101. When a user equipment establishes a communication session with a proxy call session server, a target message to be transmitted between the user equipment and the proxy call session server is obtained.

[0026] The user equipment UE can generate a request message for establishing a data session with the proxy call session server P-CSCF, and send the request message to the session management device SMF. After receiving the request message from the user equipment UE, the SMF will read the local configuration to obtain the server address information of the proxy call session server, and specifically, the active and standby P-CSCF server addresses can be obtained. Then, the user equipment receives the response message corresponding to the request message of the data session fed back by the SMF, and the response message will carry the server address information of the proxy call session server. And the server address information will also be sent to the user plane function network element UPF.

[0027] Therefore, after the user equipment establishes a communication session with the proxy call session server, the above-mentioned data call is successfully established. The user equipment can start using the IMS service. At this time, the user equipment can transmit messages with the proxy call session server P-CSCF server, wherein the message to be transmitted will be forwarded based on the user plane function network element UPF. The user plane function network element UPF obtains the target message to be transmitted between the user equipment, and the target message can be an uplink message sent by the user equipment; correspondingly, the target message can also be an uplink message sent by the proxy call session server to the user equipment. In the embodiment of the present application, the target message mainly refers to a SIP message. For example, when the target message is an uplink message, these uplink messages will be forwarded to the user plane function network element UPF through the base station.

[0028] S102: If the load of the UPF is higher than the target load threshold, the network communication address of the target message is parsed to obtain the target address information corresponding to the target message.

[0029] The target load threshold can be determined according to the current communication scenario. If the load of UPF is higher than the target load threshold, it means that UPF is in a high-load operation state. To avoid problems such as packet loss and increased delay, UPF needs to selectively discard some packets. However, in order to ensure the quality of key services, UPF needs to avoid discarding SIP messages. Therefore, after UPF obtains the target message, it will parse the network communication address of the target message to obtain its corresponding target address information. Among them, if the target message is an uplink message, the target address information is the destination address information to be sent by the user device; if the target message is a downlink message, the target address information represents the source address information of the downlink message. For example, when the user device sends an uplink message, the IP header of the corresponding network communication address will store the destination address information corresponding to the proxy call session server. Therefore, the destination address information can be directly obtained from the IP header for subsequent verification.

[0030] S103. If the target address information corresponding to the target message is consistent with the server address information pre-stored in the UPF, the target message is transmitted.

[0031] After the UPF parses the IP header information of the target message to be transmitted and obtains the corresponding target address information, it will compare it with the P-CSCF server address stored in itself. If the comparison is successful, it determines that the current target message is a SIP message, so that the SIP message can be accurately identified based on the server address information carried in the message, and then the target message is transmitted. For example, when the target message is an uplink message, the uplink message can be forwarded to the data network DN, thereby avoiding the erroneous discard of the SIP message. In the case where the target message is a downlink message sent from the proxy call session server to the user equipment, and the target address information represents the source address information of the downlink message, if the source address information corresponding to the downlink message is consistent with the server address information pre-stored by the UPF, the downlink message can be forwarded to the user equipment. Among them, the corresponding server address information of the proxy call session server pre-stored in the UPF is sent by the session management device SMF. The SMF is configured with the corresponding server address information. When the user equipment UE requests to establish a data session with the proxy call session server, the SMF will send the configured server address information to the UE and to the UPF after receiving the request information for creating the data session sent by the UE, so that the UPF can store the server address information for subsequent message verification.

[0032] In the embodiment of the present application, the UPF device is enabled to obtain the P-CSCF server address used by the UE, thereby achieving rapid and accurate identification of SIP messages. When the UPF is in a high-load state, this method can effectively prevent SIP messages from being discarded by mistake, thereby significantly improving the service quality and user experience of IMS services.

[0033] In one implementation of the embodiment of the present application, the method further includes: If the target address information corresponding to the target message is inconsistent with the server address information pre-stored in the UPF, determine the priority of the target message; if the priority of the target message is lower than the target priority, discard the target message and do not transmit the target message. Specifically, if the target message is an uplink message, the destination address information obtained by parsing the uplink message is inconsistent with the server address information pre-stored in the UPF, which means that the current uplink message is not a SIP message, then the priority of the current uplink message can be determined according to the normal message processing process. If the priority is lower than the preset target priority, it means that the uplink message is a non-critical message. When the UPF load is high, the uplink message can be discarded, that is, these uplink messages will no longer be transmitted to the corresponding data network.

[0034] In one implementation of the embodiment of the present application, when the target message is a downlink message sent from the proxy session server to the user equipment, the target address information represents the source address information of the downlink message. When a downlink message sent from the proxy call session server to the user equipment is received, the downlink message is parsed to obtain the source address information corresponding to the downlink message; if the source address information is consistent with the server address information pre-stored by the UPF, the downlink message is forwarded to the user equipment. Specifically, for downlink SIP messages sent from the P-CSCF server to the UE, when these messages arrive at the UPF, the UPF can compare the source address of the message with the P-CSCF server address stored by itself to achieve efficient and accurate SIP message identification, avoid discarding, and correctly forward to the (R)AN and UE. Among them, parsing the downlink message mainly parses the sending address corresponding to the downlink message to determine its corresponding source server address information.

[0035] In one implementation of the embodiment of the present application, the method further includes: When the user equipment sends a request message for creating a data session with the proxy call session server to the session management device SMF, the response message for creating the data session sent by the SMF is received, and the server address information corresponding to the proxy call session server carried in the response message is stored.

[0036] The communication between the session management device SMF and the user plane function network element UPF is based on the PFCP (Packet Forwarding Control Protocol) packet forwarding control protocol described in 3GPP TS 29.244. The present application may add a new field P-CSCF Server Addres (server address information) in the Session Establishment Request (session establishment request) message of the PFCP protocol. Specifically, this field may include the following information: For example, IE may exist to contain the P-CSCF server address. There may be multiple IEs of the same IE type to represent multiple P-CSCF server addresses. The order of the IE in the message indicates the priority, that is, the first IE should contain the primary P-CSCF server address, and the second IE should contain the backup P-CSCF server address. Specifically, the format of the P-CSCF server address IE can be found in Figure 3 .

[0037] Correspondingly, in an embodiment of the present application, a packet loss optimization method applied to a session management device SMF is also provided, and the method comprises the following steps: receiving a request message from a user device to establish a data session with a proxy call session server; Determine the server address information corresponding to the proxy call session server based on the configuration information of the session management device SMF itself; Sending a request message carrying server address information corresponding to the proxy call session server to the user plane function network element UPF; In response to receiving the response information of successful data session creation sent by the UPF, the response information carrying the server address information corresponding to the proxy call session server is sent to the user equipment to establish the data session between the user equipment and the proxy call session server.

[0038] For details, see Figure 4 , which shows a session creation process provided by an embodiment of the present application. The user equipment initiates a PDU session establishment request message to the network, requesting to create a new PDU session, wherein the PDU session is a data transmission channel for communication between the user equipment (UE) and the data network (DN). After receiving the PDU session establishment request message from the user equipment UE, the SMF reads the local configuration to obtain the primary and backup P-CSCF server addresses. The SMF sends a PFCP session creation request message to the UPF, and adds a P-CSCF server address field to the message, carrying the above-obtained P-CSCF primary server address and backup server address. After the UPF processes the session creation request, it replies with a PFCP session creation response message to the SMF to confirm that the session creation is successful. The SMF replies with a PDU session establishment response message to the UE, which contains the above-obtained P-CSCF primary server address and backup server address, so that the UE can use these addresses to communicate with the P-CSCF.

[0039] See also Figure 5 , which is a processing flow for uplink SIP message identification provided in an embodiment of the present application. After the session creation process is completed, the UE can start using the IMS service. At this time, when the UE sends uplink SIP messages to the P-CSCF server, these messages will be forwarded to the UPF through the base station. When the UPF is under high load, it can compare the destination address of the message with the P-CSCF server address stored in itself, so as to identify the SIP message more quickly and accurately, avoid the erroneous discard of the SIP message, and forward it correctly to the DN.

[0040] See also Figure 6 , is a processing flow of downlink SIP message identification provided by an embodiment of the present application. For downlink SIP messages sent from a P-CSCF server to a UE, when these messages arrive at the UPF, the UPF can compare the source address of the message with the P-CSCF server address stored in itself to achieve efficient and accurate SIP message identification, avoid discarding, and correctly forward them to the (R)AN and UE.

[0041] It should be noted that in the embodiment of the present application, the message interaction between the UE and the SMF needs to be transferred through the base station and the AMF in practice. Figure 1 This part is not shown in the figure, only the main data interaction process is shown in the relevant figures. The message interaction between UE and SMF, SMF and UPF, the way or field form of carrying the P-CSCF server address in the message can also be other modes, and this application does not limit this. The present invention proposes a packet loss optimization method for high-load UPF in a 5G system. The method enables the UPF device to obtain the P-CSCF server address used by the UE, thereby achieving rapid and accurate identification of SIP messages. When the UPF is in a high-load state, this method can effectively prevent the SIP message from being erroneously discarded, thereby significantly improving the service quality and user experience of the IMS service.

[0042] Based on the foregoing embodiment, an embodiment of the present application further provides a user plane function network element, including: A first acquisition unit, configured to acquire a target message to be transmitted between the user equipment and the proxy call session server when the user equipment establishes a communication session with the proxy call session server; A first parsing unit, configured to parse the network communication address of the target message to obtain target address information corresponding to the target message if the load of the user plane functional network element is higher than a target load threshold; A transmission unit is used to transmit the target message if the target address information corresponding to the target message is consistent with the server address information pre-stored in the user plane function network element.

[0043] Optionally, the user plane function network element further includes: A first determining unit, configured to determine the priority of the target message if the target address information corresponding to the target message is inconsistent with the server address information pre-stored in the user plane function network element; A message discarding processing unit, configured to discard the target message and not transmit the target message if the priority of the target message is lower than the target priority; The storage unit is used to receive response information for creating a data session sent by the SMF when the user equipment sends request information for creating a data session with the proxy call session server to the session management device SMF, and store the server address information corresponding to the proxy call session server carried in the response information.

[0044] Optionally, the user plane function network element further includes: A first transmission subunit, configured to, when the target message is an uplink message sent by a user equipment, transmit the uplink message to a data network if the target address information of the uplink message is consistent with the server address information pre-stored in the user plane function network element; The second transmission subunit is configured to forward the downlink message to the user equipment if the target message is a downlink message sent from the proxy call session server to the user equipment and if the source address information corresponding to the downlink message is consistent with the server address information pre-stored in the user plane function network element.

[0045] In an embodiment of the present application, a session management device is also provided, including: A second receiving unit, configured to receive request information from a user equipment to establish a data session with a proxy call session server; A second determining unit, configured to determine server address information corresponding to the proxy call session server based on the configuration information of the session management device itself; A first sending unit, configured to send a request message carrying server address information corresponding to the proxy call session server to a user plane function network element UPF; The second sending unit is used to send a response message carrying the server address information corresponding to the proxy call session server to the user equipment in response to receiving the response message of successful data session creation sent by the UPF, so as to establish a data session between the user equipment and the proxy call session server.

[0046] In an embodiment of the present application, a communication system is also provided, the communication system comprising a user plane function network element, a user equipment and a session management device, wherein the user equipment establishes a communication connection with a proxy call session server based on the user plane function network element and the session management device. Specifically, the execution functions of the relevant devices in the communication system can refer to the description of the above-mentioned embodiments, which will not be described in detail here.

[0047] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0048] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A packet loss optimization method applied to UPF of a 5G system, characterized in that: Applied to a user plane function network element UPF, the method comprises: When the user equipment establishes a communication session with the proxy call session server, obtaining a target message to be transmitted between the user equipment and the proxy call session server; If the load of the UPF is higher than the target load threshold, the network communication address of the target message is parsed to obtain the target address information corresponding to the target message; If the target address information corresponding to the target message is consistent with the server address information pre-stored in the UPF, the target message is transmitted.

2. The method according to claim 1, characterized in that The method further comprises: If the target address information corresponding to the target message is inconsistent with the server address information pre-stored in the UPF, determining the priority of the target message; If the priority of the target message is lower than the target priority, the target message is discarded and the target message is not transmitted.

3. The method according to claim 1, characterized in that If the target address information corresponding to the target message is consistent with the server address information pre-stored in the UPF, transmitting the target message includes: In the case where the target message is an uplink message sent by the user equipment, if the target address information of the uplink message is consistent with the server address information pre-stored by the UPF, the uplink message is transmitted to the data network, and the target address information represents the destination address information of the uplink message; When the target message is a downlink message sent by the proxy call session server to the user equipment, and the target address information represents the source address information of the downlink message, if the source address information corresponding to the downlink message is consistent with the server address information pre-stored in the UPF, the downlink message is forwarded to the user equipment.

4. The method according to claim 1, characterized in that: The method further comprises: When the user equipment sends a request message for creating a data session with the proxy call session server to the session management device SMF, the response message for creating the data session sent by the SMF is received, and the server address information corresponding to the proxy call session server carried in the response message is stored.

5. A packet loss optimization method applied to UPF of a 5G system, characterized in that: Applied to a session management device SMF, the method comprises: receiving a request message from a user device to establish a data session with a proxy call session server; Determine the server address information corresponding to the proxy call session server based on the configuration information of the session management device SMF itself; Sending a request message carrying server address information corresponding to the proxy call session server to a user plane function network element UPF; In response to receiving a response message indicating successful creation of the data session sent by the UPF, a response message carrying server address information corresponding to the proxy call session server is sent to the user equipment to establish a data session between the user equipment and the proxy call session server.

6. A user plane functional network element, characterized in that: include: A first acquisition unit, configured to acquire a target message to be transmitted between the user equipment and the proxy call session server when the user equipment establishes a communication session with the proxy call session server; A first parsing unit, configured to parse the network communication address of the target message to obtain target address information corresponding to the target message if the load of the user plane functional network element is higher than a target load threshold; A transmission unit is used to transmit the target message if the target address information corresponding to the target message is consistent with the server address information pre-stored in the user plane function network element.

7. The user plane functional network element according to claim 6, characterized in that: The user plane function network element also includes: A first determining unit, configured to determine the priority of the target message if the target address information corresponding to the target message is inconsistent with the server address information pre-stored in the user plane function network element; A message discarding processing unit, configured to discard the target message and not transmit the target message if the priority of the target message is lower than the target priority; The storage unit is used to receive response information for creating a data session sent by the SMF when the user equipment sends request information for creating a data session with the proxy call session server to the session management device SMF, and store the server address information corresponding to the proxy call session server carried in the response information.

8. The user plane functional network element according to claim 6, characterized in that: The transmission unit comprises: A first transmission subunit, configured to, when the target message is an uplink message sent by a user equipment, transmit the uplink message to a data network if the target address information of the uplink message is consistent with the server address information pre-stored in the user plane function network element; The second transmission subunit is configured to forward the downlink message to the user equipment if the target message is a downlink message sent from the proxy call session server to the user equipment and if the source address information corresponding to the downlink message is consistent with the server address information pre-stored in the user plane function network element.

9. A session management device, characterized in that: include: A second receiving unit, configured to receive request information from a user equipment to establish a data session with a proxy call session server; A second determining unit, configured to determine server address information corresponding to the proxy call session server based on the configuration information of the session management device itself; A first sending unit, configured to send a request message carrying server address information corresponding to the proxy call session server to a user plane function network element UPF; The second sending unit is used to send a response message carrying the server address information corresponding to the proxy call session server to the user equipment in response to receiving the response message of successful data session creation sent by the UPF, so as to establish a data session between the user equipment and the proxy call session server.

10. A communication system, characterized in that: The communication system comprises: The user plane function network element according to any one of claims 6 to 8, the session management device according to claim 9, and the user equipment; wherein the user equipment establishes a communication connection with the proxy call session server based on the user plane function network element and the session management device.

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