Message transmission method and device for congestion scene

Abstract

The invention discloses a message transmission method and device for a congestion scene, and the method is applied to a core network, and the method comprises the steps: transmitting a router notification message to user equipment at a first frequency, the router notification message carrying a network prefix required for the user equipment to access a network; in response to determining that the network congestion occurs, determining a congestion level value representing a network congestion degree, the congestion level value being in positive correlation with the network congestion degree; and sending a router notification message to the user equipment according to a second frequency corresponding to the congestion level value, the second frequency being greater than the first frequency, and the second frequency being in positive correlation with the congestion level value. According to the scheme, when the network congestion occurs, the issuing frequency of the router notification message is improved, and the probability that the user equipment successfully receives the router notification message in the network congestion scene is improved, so that the success rate that the user equipment accesses the network in the network congestion scene is improved.

Description

Technical Field

[0001] This application relates to the field of message transmission, and in particular to a message transmission method and apparatus for congestion scenarios. Background Technology

[0002] Network congestion refers to a situation where data traffic in a network exceeds the processing capacity of network devices. When congestion occurs, network devices (also known as network elements) typically employ flow control and congestion avoidance strategies to alleviate congestion and maintain network stability. This may involve selectively dropping some data packets to reduce network load and ensure the smooth transmission of critical data flows.

[0003] To address network congestion, various packet loss strategies exist, such as Early Random Detection (RED), priority-based packet loss, Explicit Congestion Notification (ECN), traffic shaping, and rate limiting. These methods can be flexibly selected and adjusted according to different network conditions and business needs to optimize network performance and stability. However, regardless of the packet loss strategy employed, critical data packets for users may be lost, instantly degrading user experience and even causing communication outages.

[0004] Specifically, in fifth-generation communication networks (i.e., 5G networks), user equipment (UEs) obtain network addresses (such as IPv6 addresses) primarily through two automatic configuration mechanisms: Stateless Address Autoconfiguration (SLAAC) and Stateful Address Autoconfiguration (DHCPv6). During SLAAC, the UE first generates a link-local address, used for communication on the local link. Then, the UE actively sends a Router Solicitation (RS) message to the User Plane Function (UPF) element of the 5G core network through the base station to obtain the network prefix. Upon receiving the request, the UPF element encapsulates the RS message and forwards it to the Session Management Function (SMF).

[0005] After receiving the RS message, SMF allocates an IPv6 network prefix from the configured network prefix pool for stateless address autoconfiguration and includes this prefix in a Router Advertisement (RA) message sent to UPF. The RA message may also contain other network configuration information, such as the default gateway address and additional parameters.

[0006] The UPF network element then encapsulates the RA message and sends it back to the UE via the base station. The UE extracts the network prefix carried in the RA message and combines it with its own interface identifier to generate an IPv6 address, thereby enabling subsequent network communication based on the IPv6 address.

[0007] However, when network congestion occurs in a 5G network, the UPF may implement congestion control and packet loss strategies to alleviate congestion. In this case, RS and RA packets may be discarded by the UPF network element and lost, thereby preventing the normal generation of IPv6 addresses and affecting the network access of user equipment. Summary of the Invention

[0008] To improve the success rate of user equipment accessing the network in network congestion scenarios, this application discloses the following technical solution:

[0009] The first aspect of this application provides a message transmission method for congestion scenarios, applied to a core network, the method comprising:

[0010] A router advertisement message is sent to the user equipment at a first frequency, the router advertisement message carrying the network prefix required for the user equipment to access the network;

[0011] In response to determining that network congestion has occurred, a congestion level value characterizing the degree of network congestion is determined, wherein the congestion level value is positively correlated with the degree of network congestion;

[0012] The router announcement message is sent to the user equipment at a second frequency corresponding to the congestion level value, the second frequency being greater than the first frequency, and the second frequency being positively correlated with the congestion level value.

[0013] Optionally, the core network includes user plane network elements and session management network elements;

[0014] The step of sending the router advertisement message to the user equipment at a second frequency corresponding to the congestion level value includes:

[0015] The user plane network element sends a session report request signaling carrying the congestion level value to the session management network element;

[0016] The session management network element calculates a second frequency between a preset upper and lower frequency limit based on the congestion level value;

[0017] The session management network element sends the router advertisement message to the user plane network element based on the second frequency, thereby triggering the user plane network element to forward the router advertisement message to the user equipment.

[0018] Optionally, determining the congestion level value characterizing the degree of network congestion includes:

[0019] Obtain network load metrics, which include at least the bandwidth utilization of the user plane network element;

[0020] The congestion level value is determined based on the network load metric.

[0021] Optional, also includes:

[0022] A second priority value is determined based on the degree of congestion. The second priority value is greater than the first priority value. The first priority value is the priority value of the router advertisement message and the router request message when no network congestion occurs. The second priority value is positively correlated with the congestion level value.

[0023] Adjust the priority values ​​of both the router advertisement message and the router request message to the second priority value;

[0024] The router request message is sent by the user equipment to trigger the core network to send a router advertisement message. The higher the priority value of the message, the lower the probability of the message being dropped.

[0025] Optional, also includes:

[0026] In response to determining that network congestion has been relieved, the priority values ​​of both the router advertisement message and the router request message are adjusted to the first priority value.

[0027] Optionally, the core network includes user plane network elements and session management network elements, and the method further includes:

[0028] In response to determining that network congestion has occurred, the user plane network element buffers the router advertisement message sent by the session management network element;

[0029] In response to receiving a router request message from a first user equipment, the user plane network element queries its cache to see if there is a first router advertisement message corresponding to the first user equipment. The first user equipment refers to any user equipment connected to the core network.

[0030] If the cache contains the first router advertisement message, the user plane network element encapsulates the first router advertisement message and sends it back to the first user equipment.

[0031] Optionally, it may also include at least one of the following:

[0032] In response to determining that network congestion has been relieved, the user plane network element deletes the cached router advertisement message;

[0033] In response to determining that the first user equipment has accessed the core network, the user plane network element deletes the first router advertisement message from its cache.

[0034] A second aspect of this application provides a message transmission apparatus for congestion scenarios, applied in a core network, comprising:

[0035] The session management network element is used to send a router advertisement message to the user equipment at a first frequency. The router advertisement message carries the network prefix required by the user equipment to access the network.

[0036] User plane network elements are used to determine a congestion level value characterizing the degree of network congestion in response to determining that network congestion has occurred, wherein the congestion level value is positively correlated with the degree of network congestion;

[0037] The session management network element is used to send the router announcement message to the user equipment at a second frequency corresponding to the congestion level value, wherein the second frequency is greater than the first frequency and the second frequency is positively correlated with the congestion level value.

[0038] Optionally, the session management network element is used to send the router advertisement message to the user equipment at a second frequency corresponding to the congestion level value, including:

[0039] The user plane network element sends a session report request signaling carrying the congestion level value to the session management network element;

[0040] The session management network element calculates a second frequency between a preset upper and lower frequency limit based on the congestion level value;

[0041] The session management network element sends the router advertisement message to the user plane network element based on the second frequency, thereby triggering the user plane network element to forward the router advertisement message to the user equipment.

[0042] Optionally, the user plane network element determines a congestion level value characterizing the degree of network congestion, including:

[0043] Obtain network load metrics, which include at least the bandwidth utilization of the user plane network element;

[0044] The congestion level value is determined based on the network load metric.

[0045] This application discloses a message transmission method and apparatus for congestion scenarios, applied to a core network. The method includes: sending router advertisement messages to user equipment at a first frequency, the router advertisement messages carrying the network prefix required for the user equipment to access the network; in response to determining that network congestion has occurred, determining a congestion level value characterizing the degree of network congestion, the congestion level value being positively correlated with the degree of network congestion; and sending router advertisement messages to the user equipment at a second frequency corresponding to the congestion level value, the second frequency being greater than the first frequency and positively correlated with the congestion level value. This solution increases the frequency of router advertisement message delivery when network congestion occurs, increasing the probability that the user equipment will successfully receive the router advertisement messages in network congestion scenarios, thereby improving the success rate of user equipment accessing the network in network congestion scenarios. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0047] Figure 1 This is a flowchart of a message transmission method for a congestion scenario provided in an embodiment of this application;

[0048] Figure 2 This is a schematic diagram of message interaction for a message transmission method in a congestion scenario provided in an embodiment of this application;

[0049] Figure 3 This is a schematic diagram of an IPv4 packet header provided in an embodiment of this application;

[0050] Figure 4 This is a schematic diagram of an IPv6 packet header provided in an embodiment of this application;

[0051] Figure 5 This is a schematic diagram of a core network cached message provided in an embodiment of this application;

[0052] Figure 6 This is a schematic diagram of the structure of a core network provided in an embodiment of this application. Detailed Implementation

[0053] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] This application provides a message transmission method for congestion scenarios, applied to the core network. Please refer to [link to relevant documentation]. Figure 1 The method may include the following steps.

[0055] S101 sends a router advertisement message to the user equipment at the first frequency. The router advertisement message carries the network prefix required for the user equipment to access the network.

[0056] S102, in response to determining that network congestion has occurred, determines a congestion level value that characterizes the degree of network congestion, and the congestion level value is positively correlated with the degree of network congestion.

[0057] S103, send a router advertisement message to the user equipment at the second frequency corresponding to the congestion level value. The second frequency is greater than the first frequency, and the second frequency is positively correlated with the congestion level value.

[0058] In this scheme, the core network sends router advertisement messages to user equipment at a first frequency. These messages carry the network prefix required for user equipment to access the network. In response to determining network congestion, a congestion level value representing the degree of congestion is determined, and this value is positively correlated with the degree of congestion. Router advertisement messages are then sent to user equipment at a second frequency corresponding to the congestion level value. This second frequency is greater than the first frequency and is also positively correlated with the congestion level value. This scheme increases the frequency of router advertisement message delivery when network congestion occurs, increasing the probability that user equipment will successfully receive these messages in congested scenarios, thereby improving the success rate of user equipment accessing the network. In other words, this embodiment can correspondingly increase the frequency of router advertisement message delivery as network congestion intensifies, thereby increasing the chance of successfully forwarding router advertisement messages to user equipment, and ultimately improving the stability and reliability of network services.

[0059] In step S101, the first frequency can be the default frequency specified in the relevant communication protocol when no network congestion occurs. For example, the first frequency can be 1, then the session management network element can send one corresponding router advertisement message to the user plane network element for each router request message it receives.

[0060] In step S102, whether network congestion has occurred can be determined based on relevant network indicators in the core network. For example, it can be determined based on the bandwidth utilization of user plane network elements. If the bandwidth utilization is greater than a preset threshold, such as greater than 80%, it is determined that network congestion has occurred. If it is less than or equal to the threshold, it is determined that network congestion has not occurred.

[0061] Optionally, the congestion level value representing the degree of network congestion may include:

[0062] Obtain network load metrics, which should include at least the bandwidth utilization of user plane network elements;

[0063] The congestion level is determined based on network load metrics.

[0064] One method for determining the congestion level value is to predetermine multiple ranges of network indicators, each range corresponding to a congestion level value. When network congestion is determined, the range in which the current network indicator is located is determined, and the congestion level value corresponding to that range is determined as the current congestion level value.

[0065] For example, several bandwidth utilization ranges are set, such as 80% to 82%, 82% to 84%, and 84% to 86%, which correspond to congestion level values ​​1, 2, and 3, respectively. When network congestion is determined to occur, the bandwidth utilization of the current user plane network element is obtained. If the current bandwidth utilization is determined to be between 82% and 84%, then the congestion level value is determined to be 2.

[0066] The bandwidth utilization rate in the above example can also be replaced with other network load metrics that can represent user plane load.

[0067] Optionally, the core network includes user plane network elements and session management network elements, and the implementation method of step S103 can be:

[0068] The user plane network element sends a session report request signaling carrying the congestion level value to the session management network element;

[0069] The session management network element calculates a second frequency between the preset upper and lower frequency limits based on the congestion level value;

[0070] The session management network element sends a router advertisement message to the user plane network element based on the second frequency, thereby triggering the user plane network element to forward the router advertisement message to the user equipment.

[0071] In congested scenarios, even if the user plane network element retransmits the router advertisement message, it may still encounter packet loss again, leading to retransmission failure. To address this issue, the core network needs to design and implement an effective retransmission mechanism. According to the 3GPP 29244 specification, the Session Report Request signaling of the Packet Forwarding Control Protocol (PFCP) defines Overload Control Information (IE). This information is used to enable the UPF to send a signal to the Session Management Element (SMF) when the user plane network element (UPF) is overloaded, i.e., when network congestion occurs. This allows the SMF to take timely measures to reduce the transmitted traffic, thereby alleviating network congestion.

[0072] However, current overload control information does not intuitively reflect the congestion level of the UPF, which limits its accuracy and effectiveness in practical applications. Therefore, this embodiment adds a congestion level element to the overload control information to explicitly indicate the congestion level of the current user plane network element, thereby enabling the SMF to more accurately understand the network condition and make corresponding control decisions accordingly.

[0073] In this embodiment, when the UPF sends a Session Report Request signaling to the SMF to indicate the network congestion status of the UPF, the Session Report Request signaling should carry congestion level elements. Based on these congestion level elements, the SMF can determine the congestion level of the UPF and take further countermeasures.

[0074] The encoding format of Congestion Level IE features can be shown in Table 1. The feature type value of Congestion Level IE features can use type values ​​not defined in the 3GPP 29244 specification, such as 300. The Congestion level value is the congestion level value, which is usually encoded as 1 byte.

[0075] Table 1

[0076]

[0077] Upon receiving the session report request signaling, the session management network element replies with a session report response signaling to the user plane network element to confirm receipt of the session report request signaling.

[0078] On the other hand, the session management network element extracts the congestion level elements carried by the signaling, then parses the congestion level elements to obtain the congestion level value, and then calculates the second frequency based on the following formula (1), according to the currently parsed congestion level value n, the upper frequency limit y, and the lower frequency limit x.

[0079]

[0080] Where m represents the upper limit of the congestion level value, and its value is unlimited. As an example, m can be equal to 15. z is the calculated second frequency. In formula (1), [] indicates that the value in the square brackets is rounded up.

[0081] In this embodiment, both the upper and lower frequency limits are pre-configured parameters. Generally, the default frequency of router announcement messages specified by the communication protocol when no network congestion occurs, i.e., the aforementioned first frequency, can be used as the lower frequency limit. Based on this, a value greater than the lower frequency limit can be determined as the upper frequency limit according to actual needs.

[0082] The session management network element sends router advertisement messages to the user plane network element based on the second frequency, which may include:

[0083] The session management network element sends router advertisement messages to the user plane network element multiple times based on the second frequency, triggering the user plane network element to forward the router advertisement messages to the user equipment.

[0084] The session management network element sends router advertisement messages to the user plane network element based on the second frequency, which may also include:

[0085] The session management network element sends a router advertisement message only once to the user plane network element, but will send advertisement messages to the user plane network element multiple times based on the second frequency to issue instructions, so as to trigger the user plane network element to forward the router advertisement message to the user equipment multiple times.

[0086] In this embodiment, the upper frequency limit, lower frequency limit, first frequency, and second frequency can all be represented by the number of times the corresponding router advertisement message is allowed to be repeatedly sent after receiving a router request message. As an example, the first frequency and the lower frequency limit are equal, both being 1, indicating that the same router advertisement message is not allowed to be repeatedly sent by default. The upper frequency limit can be set to 10, and the second frequency can be 3, 5, or other values ​​less than or equal to 10, depending on the congestion level value.

[0087] The following is combined with Figure 2 The examples illustrate the methods of the above embodiments.

[0088] S201 When a user plane network element determines that network congestion has occurred, it determines the congestion level value based on bandwidth utilization.

[0089] S202, the user plane network element sends the congestion level value to the session management network element through the session report request signaling.

[0090] S203, the session management network element sends a session report response signaling back to the user plane network element to confirm receipt.

[0091] S204, the user equipment sends a router request message to the user plane network element via the base station.

[0092] S205, the user plane network element forwards the router request message to the session management network element.

[0093] S206, the session management network element assigns network prefix information to user equipment.

[0094] S207, the session management network element determines the second frequency as 3 based on the congestion level value.

[0095] It should be noted that the execution order of step S207 is not limited to... Figure 2 For example, this step can be performed simultaneously with S206, or it can be performed immediately after the session management element receives the congestion level value.

[0096] The second frequency is 3, which means that after receiving the router request message, the core network needs to respond to the router request message by sending the router advertisement message to the user equipment three times.

[0097] S208, the session management network element sends a router advertisement message to the user plane network element.

[0098] The router advertisement message carries the network prefix information allocated in S206.

[0099] S209, the user plane network element forwards the router advertisement message to the user equipment.

[0100] During this forwarding, due to severe network congestion, the user's device did not receive the router's notification message.

[0101] S210, the session management network element sends two announcement messages to the user plane network element to issue instructions.

[0102] S211, the user plane network element continues to forward the router advertisement message twice to the user equipment.

[0103] When S211 is repeatedly transmitted, the user equipment may successfully receive the router advertisement message due to the possibility of additional flow control measures or improved network conditions, thus enabling it to successfully access the core network.

[0104] It should be noted that the router advertisement message forwarded in S211 and the router advertisement message forwarded in S209 are the same message, that is, the content of the two is exactly the same.

[0105] Using the above methods, after receiving the router request message from the user equipment, the core network sends the same router corresponding to the router request message to the user equipment a total of 3 times, which increases the probability that the router advertisement message is successfully received by the user equipment.

[0106] Optionally, if network congestion is determined to occur, the method of this embodiment can further adjust the priority of packets used for network access in the following manner:

[0107] The second priority value is determined based on the degree of congestion. The second priority value is greater than the first priority value. The first priority value is the priority value of router advertisement messages and router request messages when no network congestion occurs. The second priority value is positively correlated with the congestion level value.

[0108] Adjust the priority values ​​of both the router advertisement message and the router request message to the second priority value;

[0109] Among them, the router request message is sent by the user equipment to trigger the core network to send a router advertisement message. The higher the priority value of the message, the lower the probability of the message being dropped.

[0110] Differentiated Services Code Point (DSCP) values ​​are Quality of Service (QoS) markers in network protocols (such as IP) used to prioritize data packets to meet different QoS requirements. DSCP values ​​range from 0 to 63, representing 64 different priorities or service classes. These values ​​are typically organized into several categories, such as Best-Effort, Assured Forwarding (AF), and Expedited Forwarding (EF), to meet the needs of different network applications and services. Generally, a higher DSCP value indicates a higher priority for the data packet. The priority values ​​in this embodiment are equivalent to the DSCP values ​​described above.

[0111] In IPv4, the DSCP value is represented by the first 6 bits of the Type of Service (TOS) field in the IPv4 packet header. For example... Figure 3 As shown, in IPv6, the DSCP value is represented using the first 6 bits of the TrafficClass field in the IPv6 packet header. Figure 4 As shown.

[0112] In the core network, network elements (or network devices) typically identify packet priorities based on the DSCP value in the IP packet header and process packets accordingly. Packets with higher DSCP values ​​may be prioritized for forwarding to ensure timely processing even during network congestion. Conversely, packets with lower DSCP values ​​may be delayed or dropped to guarantee efficient utilization of network resources.

[0113] To optimize network performance and user experience during network congestion, UPF can prioritize forwarding RS / RA packets by adjusting their DSCP priority. Specifically, the strategy dynamically adjusts the DSCP value of RS / RA packets based on the level of network congestion. During light congestion, the DSCP value of RS / RA packets is set to a lower priority; as congestion worsens, the DSCP value is gradually increased; and under heavy congestion, the DSCP value is set to the highest priority.

[0114] Based on the above characteristics, in this embodiment, the user plane network element can determine the second priority value b according to the degree of congestion based on the following formula (2).

[0115]

[0116] In formula (2), q is the value of the indicator representing the degree of congestion at the current moment. This value can be obtained from the user plane network element. For example, q can be the bandwidth utilization rate of the user plane network element at the current moment. p is the value of the indicator representing the degree of congestion when network congestion just occurs. It can be understood as the threshold for measuring whether network congestion has occurred. That is, when the indicator is greater than p, network congestion is determined to have occurred, and when the indicator is less than or equal to p, network congestion is determined not to have occurred. As an example, p can be the threshold of bandwidth utilization rate. For example, p can be equal to 90%.

[0117] 'a' represents the default first priority value configured for router request messages and router advertisement messages when no network congestion occurs. The specific value of this first priority value is determined by the relevant communication specifications and is not limited. In this embodiment, the user plane network element can parse the received router request messages and router advertisement messages to obtain the first priority value when no network congestion occurs.

[0118] 100% represents the upper limit of congestion level, for example, the upper limit of bandwidth utilization. In formula (2), [] indicates that the value within the square brackets is rounded up.

[0119] After determining the second priority value, each time the user plane network element receives a router request message and each time it receives a router advertisement message, it changes the original first priority value of the message to the second priority value, and then forwards the message with the modified priority value to the session management network element and / or user equipment.

[0120] By using the above methods, the core network can increase the priority value of router advertisement messages and router request messages when network congestion occurs. Furthermore, as the degree of network congestion increases, the priority value of router advertisement messages and router request messages increases synchronously. This allows router advertisement messages and router request messages to be forwarded preferentially by network elements in the core network, thereby increasing the probability that user equipment will successfully receive router advertisement messages.

[0121] Optional, also includes:

[0122] In response to the determination that network congestion has been cleared, the priority values ​​of both Router Advertisement messages and Router Request messages are adjusted to the first priority value.

[0123] In this embodiment, the user plane network element can determine that network congestion is resolved when the bandwidth utilization rate is less than a preset threshold, such as less than 80% or less than 90%.

[0124] If network congestion is confirmed to be resolved, and there are router advertisement messages and router request messages that were previously adjusted to the second priority value, the user plane network element can adjust the priority value of these router advertisement messages and router request messages to the first priority value to avoid the router advertisement messages and router request messages having too high a priority value and affecting the transmission of other messages.

[0125] Optionally, the core network includes user plane network elements and session management network elements. In the event of network congestion, the method of this embodiment can further process router request messages and router advertisement messages as follows to increase the probability that user equipment will receive router advertisement messages and join the network. The specific processing method is as follows:

[0126] In response to the determination that network congestion has occurred, the user plane network element buffers the router advertisement message sent by the session management network element;

[0127] In response to receiving a router request message from the first user equipment, the user plane network element queries its cache to see if there is a first router advertisement message corresponding to the first user equipment. The first user equipment refers to any user equipment connected to the core network.

[0128] If the cache contains the first router advertisement message, the user plane network element will encapsulate the first router advertisement message and send it back to the first user equipment.

[0129] When network congestion is detected, each time a user plane network element receives a router advertisement message, it can store the router advertisement message and the corresponding session information in its own cache. For example, the user plane network element's cache can store: session information 1 and the corresponding router advertisement message 1, session information 2 and the corresponding router advertisement message 2, session information 3 and the corresponding router advertisement message 3, etc.

[0130] The session information corresponding to the router advertisement message may include any information carried in the router request message corresponding to the router advertisement message that can characterize the identity of the user equipment that sent the router request message. For example, the session information may be the link-local address carried in the router request message when the user equipment sends the router request message.

[0131] As an example, User Equipment A sends Router Request Message 1 to a User Plane Network Element, which carries the Link Local Address X. The User Plane Network Element forwards Router Request Message 1 to the Session Management Network Element. In response to Router Request Message 1, the Session Management Network Element sends back Router Advertisement Message 1 carrying the Network Prefix Address. The User Plane Network Element forwards Router Advertisement Message 1 to User Equipment A and caches Router Advertisement Message 1 locally, and caches the Link Local Address X as the Session Information 1 corresponding to Router Advertisement Message 1.

[0132] Based on caching router advertisement messages and their corresponding session information, each time a router request message is received, the user plane network element can query the cache to see if there is session information that matches the router request message.

[0133] Taking the receipt of a router request message from the first user device as an example, if there is matching session information, it means that the user plane network element has the router advertisement message required by the user device in its local cache. Therefore, the user plane network element encapsulates the router advertisement message corresponding to the matching session information and sends it back to the user device, without having to forward the router request message to the session management network element.

[0134] If no matching session information is found, it means that the user plane network element does not have the router advertisement message required by the user device cached locally. Therefore, the user plane network element forwards the router request message to the session management network element, so that the session management network element replies with the router advertisement message.

[0135] Based on the previous example, if the received router request message matches the cached session information 2, the user plane network element will encapsulate the cached router advertisement message 2 and forward it to the first user equipment.

[0136] The following uses the interaction process between the first user equipment, the user plane network element, and the session management network element as an example to illustrate the execution method of the above embodiments. Please refer to [link to relevant documentation]. Figure 5 The interaction process includes the following steps.

[0137] S501, The first user equipment sends a router request message 1 to the user plane network element via the base station.

[0138] S502, The user plane network element forwards the router request message 1 to the session management network element.

[0139] In step S502, the user plane network element can first decapsulate the GPRS tunnel protocol header (i.e., the GTP tunnel header) of Router Request Message 1, and then forward Router Request Message 1 to the session management network element. The decapsulation method can be found in relevant communication specifications and will not be elaborated here.

[0140] S503, the session management network element, assigns a network prefix to the first user equipment.

[0141] S504. The session management network element sends a router advertisement message 1 to the user plane network element.

[0142] Router advertisement message 1 carries the network prefix assigned to the first user device by the session management network element.

[0143] S505, User plane network element caches router advertisement message 1 and session information of the first user device 1.

[0144] The initial step of caching this message ensures that even if the router advertisement message 1 is lost in subsequent processes, the user plane network elements still have a backup. The session information 1 of the first user equipment can be, for example, the link-local address of the first user equipment carried in the router request message 1, or other information that can identify the first user equipment carried in the router request message 1.

[0145] S506, the user plane network element forwards router advertisement message 1 to the first user equipment.

[0146] It should be noted that the execution order of steps S505 and S506 is not limited to... Figure 5 In practice, S505 and S506 can be executed simultaneously, or S506 can be executed first and then S505.

[0147] Assuming that in S506, due to network overload or other interference, router advertisement message 1 is lost during transmission and is not received by the first user equipment.

[0148] S507, the first user equipment sends a router request message 1 to the user plane network element again.

[0149] The first user equipment can start timing after sending Router Request Message 1. If the first user equipment still does not receive the Router Advertisement Message after the preset timeout period since sending Router Request Message 1, the first user equipment can determine that receiving the advertisement message has failed. Then, in response to the failure to receive the advertisement message, it executes S507 to try to access the core network again.

[0150] S508, the user plane network element retrieves session information 1 that matches the router request message 1 from the cache.

[0151] S509, the user plane network element forwards the router advertisement message 1 corresponding to session information 1 in the cache to the first user device.

[0152] In step S509, the user plane network element can first encapsulate the router advertisement message 1 into GTP tunnel information, and then send the GTP tunnel information to the first user equipment through the base station. After receiving the GTP tunnel information, the first user equipment can decapsulate it and obtain the router advertisement message 1.

[0153] Using the above method, this embodiment can cache router advertisement messages in user plane network elements when network congestion occurs. If the router advertisement message is lost due to interference such as network congestion when the user plane network element forwards it to the user equipment, the user plane network element can respond to the router request message sent by the user equipment again and forward the previously cached router advertisement message to the user equipment. This avoids the repeated interaction process between the user plane network element and the session management network element after the router advertisement message is lost. It can alleviate the interaction between network elements in the core network and reduce the load, and also reduce the risk of message loss.

[0154] Optionally, it may also include at least one of the following:

[0155] In response to the confirmation that network congestion has been cleared, the user plane network element deletes the cached router advertisement message;

[0156] In response to the determination that the first user equipment has been connected to the core network, the user plane network element deletes the first router advertisement message from its cache.

[0157] The method for determining network congestion resolution is the same as described in the previous embodiments and will not be repeated here. Once network congestion is resolved, it is no longer necessary to improve the success rate of user equipment receiving router advertisement messages by caching them. Therefore, all currently cached router advertisement messages on the user plane network element can be directly deleted, and router advertisement messages will not be cached again unless network congestion occurs, thus saving cache space on the user plane network element.

[0158] The following methods are used to determine whether the first user equipment has been connected to the core network:

[0159] User plane network elements can continuously monitor received packets, such as IPv4 packets and / or IPv6 packets. If the network prefix carried in a packet is the same as the network prefix carried in the first router advertisement packet, it means that the first user equipment has successfully received the first router advertisement packet and generated a valid network address, such as an IPv6 address and / or an IPv4 address, based on the first router advertisement packet. Therefore, it can be determined that the first user equipment has successfully accessed the core network.

[0160] The first router advertisement message refers to the router advertisement message that needs to be cached by the user plane network element and should be forwarded to the first user device.

[0161] Once the first user equipment has successfully connected to the core network, the user plane network element no longer needs to forward the first router advertisement message to the first user equipment. Therefore, this successfully used first router advertisement message can be deleted from the cache to free up the cache space of the user plane network element.

[0162] This application also provides a message transmission device for congestion scenarios, applied to the core network. Please refer to [link to relevant documentation]. Figure 6 ,include:

[0163] The session management network element 601 is used to send a router advertisement message to the user equipment at a first frequency. The router advertisement message carries the network prefix required by the user equipment to access the network.

[0164] User plane network element 602 is used to determine a congestion level value that characterizes the degree of network congestion in response to determining that network congestion has occurred. The congestion level value is positively correlated with the degree of network congestion.

[0165] The session management network element 601 is used to send router advertisement messages to user equipment at a second frequency corresponding to the congestion level value. The second frequency is greater than the first frequency, and the second frequency is positively correlated with the congestion level value.

[0166] Optionally, the session management network element 601 is used to send router advertisement messages to the user equipment at a second frequency corresponding to the congestion level value, including:

[0167] The user plane network element sends a session report request signaling carrying the congestion level value to the session management network element;

[0168] The session management network element calculates a second frequency between the preset upper and lower frequency limits based on the congestion level value;

[0169] The session management network element sends a router advertisement message to the user plane network element based on the second frequency, thereby triggering the user plane network element to forward the router advertisement message to the user equipment.

[0170] Optionally, user plane network element 602 determines a congestion level value characterizing the degree of network congestion, including:

[0171] Obtain network load metrics, which should include at least the bandwidth utilization of user plane network elements;

[0172] The congestion level is determined based on network load metrics.

[0173] Optionally, the user plane network element 602 is also used for:

[0174] The second priority value is determined based on the degree of congestion. The second priority value is greater than the first priority value. The first priority value is the priority value of router advertisement messages and router request messages when no network congestion occurs. The second priority value is positively correlated with the congestion level value.

[0175] Adjust the priority values ​​of both the router advertisement message and the router request message to the second priority value;

[0176] Among them, the router request message is sent by the user equipment to trigger the core network to send a router advertisement message. The higher the priority value of the message, the lower the probability of the message being dropped.

[0177] Optionally, the user plane network element 602 also includes:

[0178] In response to the determination that network congestion has been cleared, the priority values ​​of both Router Advertisement messages and Router Request messages are adjusted to the first priority value.

[0179] Optionally, the core network includes user plane network elements and session management network elements. User plane network element 602 is also used for:

[0180] In response to the determination that network congestion has occurred, the user plane network element buffers the router advertisement message sent by the session management network element;

[0181] In response to receiving a router request message from the first user equipment, the user plane network element queries its cache to see if there is a first router advertisement message corresponding to the first user equipment. The first user equipment refers to any user equipment connected to the core network.

[0182] If the cache contains the first router advertisement message, the user plane network element will encapsulate the first router advertisement message and send it back to the first user equipment.

[0183] Optionally, the user plane network element 602 is also used for at least one of the following:

[0184] In response to the confirmation that network congestion has been cleared, the user plane network element deletes the cached router advertisement message;

[0185] In response to the determination that the first user equipment has been connected to the core network, the user plane network element deletes the first router advertisement message from its cache.

[0186] The working principle of the core network in this embodiment can be found in the relevant steps of the packet transmission method in the congestion scenario in the previous embodiment, and will not be repeated here.

[0187] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0188] For ease of description, the above systems or devices are described separately as various modules or units based on their functions. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware components.

[0189] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0190] Finally, it should be noted that in this document, relational terms such as first, second, third, and fourth are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0191] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for packet transmission in a congestion scenario, the method comprising: The method is applied to a core network, and the method comprises: sending a router advertisement message to a user equipment at a first frequency, the router advertisement message carrying a network prefix required by the user equipment to access a network; in response to determining that network congestion occurs, determining a congestion level value representing a degree of network congestion, the congestion level value being positively correlated with the degree of network congestion; sending the router advertisement message to the user equipment at a second frequency corresponding to the congestion level value, the second frequency being greater than the first frequency, and the second frequency being positively correlated with the congestion level value.

2. The method of claim 1, wherein, The core network comprises a user plane network element and a session management network element; The sending of the router advertisement message to the user equipment at the second frequency corresponding to the congestion level value comprises: The user plane network element sends a session report request signaling carrying the congestion level value to the session management network element; The session management network element calculates a second frequency between a preset upper limit of frequency and a lower limit of frequency according to the congestion level value; The session management network element sends the router advertisement message to the user plane network element based on the second frequency, so as to trigger the user plane network element to forward the router advertisement message to the user equipment.

3. The method of claim 1, wherein, The determination of the congestion level value representing the degree of network congestion comprises: obtaining a network load indicator, the network load indicator at least comprising a bandwidth utilization rate of the user plane network element; determining the congestion level value according to the network load indicator.

4. The method of claim 1, wherein, Further comprising: determining a second priority value according to the degree of congestion, the second priority value being greater than a first priority value, the first priority value being a priority value of the router advertisement message and a router request message in a case where network congestion does not occur, and the second priority value being positively correlated with the congestion level value; adjusting the priority values of the router advertisement message and the router request message to the second priority value; wherein the router request message is sent by the user equipment to trigger the core network to feed back the router advertisement message, and the higher the priority value of the message is, the lower the probability of discarding the message is.

5. The method of claim 4, wherein, Further comprising: in response to determining that network congestion is removed, adjusting the priority values of the router advertisement message and the router request message to the first priority value.

6. The method of claim 1, wherein, The core network comprises a user plane network element and a session management network element, and the method further comprises: in response to determining that network congestion occurs, the user plane network element buffering a router advertisement message sent by the session management network element; in response to receiving a router request message of a first user equipment, the user plane network element querying whether there is a first router advertisement message corresponding to the first user equipment in the buffer, the first user equipment referring to any user equipment connected to the core network; if the first router advertisement message is in the buffer, the user plane network element feeds back the first router advertisement message to the first user equipment after encapsulating the first router advertisement message.

7. The method of claim 6, wherein, Further comprising at least one of: in response to determining that network congestion is removed, the user plane network element deleting the buffered router advertisement message; in response to determining that the first user equipment has accessed the core network, the user plane network element deleting the first router advertisement message in the buffer.

8. A packet transmission apparatus of a congestion scenario, characterized by, The method is applied to a core network, and the method comprises: A session management network element is configured to send a router advertisement message to a user equipment at a first frequency, the router advertisement message carrying a network prefix required by the user equipment to access a network; A user plane network element is configured to determine a congestion level value representing a degree of network congestion in response to determining that network congestion occurs, the congestion level value being positively correlated with the degree of network congestion; The session management network element is configured to send the router advertisement message to the user equipment according to a second frequency corresponding to the congestion level value, the second frequency being greater than the first frequency, and the second frequency being positively correlated with the congestion level value.

9. The apparatus of claim 8, wherein, The session management network element is configured to send the router advertisement message to the user equipment according to a second frequency corresponding to the congestion level value, including: The user plane network element sends a session report request signaling carrying the congestion level value to the session management network element; The session management network element calculates the second frequency between a preset upper limit of frequency and a lower limit of frequency according to the congestion level value; The session management network element sends the router advertisement message to the user plane network element based on the second frequency, so as to trigger the user plane network element to forward the router advertisement message to the user equipment.

10. The apparatus of claim 8, wherein, The user plane network element determines the congestion level value representing the degree of network congestion, including: Obtaining a network load index, the network load index at least including a bandwidth utilization of the user plane network element; Determining the congestion level value according to the network load index.

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