A congestion control method, system, device and medium based on the CDN network

Abstract

The present invention discloses a congestion control method, system, device and medium based on a CDN network. The method includes: obtaining a user's request; parsing the request to obtain a first cache server sequence of a cache layer; screening according to the path lengths of the first cache servers; calculating a discard threshold parameter for each first cache server in the first cache server sequence through a dynamic threshold algorithm, removing the first cache servers with discard threshold parameters lower than a control threshold from the cache server sequence to obtain a second cache server sequence; adjusting the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate and obtaining an optimal cache server with the highest cache sending rate; and returning the required content of the request through the optimal cache server. The present invention can improve the timeliness of the CDN network and relieve the congestion of the CDN network.

Description

Technical Field

[0001] The present invention relates to the technical field of CDN network congestion control, and in particular, to a congestion control method, system, device and medium based on a CDN network. Background Art

[0002] Network congestion refers to a continuous overloaded network state in which the demand of communication requests for network resources exceeds the inherent capacity of the network. The most important performance parameters of an interconnected network are delay and throughput. After congestion occurs, the transmission delay of network packets increases, the throughput of the network decreases, and the overall performance of the network deteriorates. According to whether network packets can be discarded after congestion occurs, interconnected networks are divided into two categories: lossy networks and lossless networks. Lossy networks relieve congestion through operations such as packet loss and slow start. Lossless networks do not experience packet loss, but when there is competition for network resources, network packet delays also increase and network throughput decreases due to queuing. When network communication hotspots persist, network performance will also be greatly reduced. High-performance interconnected networks belong to lossless networks and have higher requirements for delay and throughput. Solving congestion control in high-performance interconnected networks is more challenging.

[0003] Regarding the congestion control of the CDN network, it only stays at searching for the cache server with the lowest current load, without performing dynamic congestion control, and even less taking congestion adjustment on the cache server according to the congestion situation. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. For this purpose, the present invention provides a congestion control method, system, device and medium based on a CDN network, which can dynamically screen out cache servers with lower congestion in the first cache server sequence according to the dynamic threshold method when the cache servers are selected according to the path sorting, and adjust the cache sending rate in the second cache server according to the packet loss rate, and realize high bandwidth utilization of the cache server by adjusting the cache sending rate, reduce the delay of the CDN network, and improve the timeliness of content forwarding.

[0005] In a first aspect, an embodiment of the present invention provides a congestion control method based on a CDN network, including:

[0006] Obtain a request from a user;

[0007] Parse the request to obtain a first cache server sequence of a cache layer; the first cache server sequence is screened according to the path length of the first cache server;

[0008] Calculate the abandonment threshold parameter of each first cache server in the first cache server sequence through a dynamic threshold algorithm, and remove the first cache servers with the abandonment threshold parameter lower than the control threshold from the cache server sequence to obtain a second cache server sequence;

[0009] Adjust the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate and obtain the best cache server with the highest cache sending rate;

[0010] Return the required content of the request through the best cache server.

[0011] The method according to the embodiment of the present invention has at least the following beneficial effects:

[0012] This method first parses the request to obtain a first cache server sequence with the path of the request from short to long, which can accelerate the speed at which the user opens the required content of the request and improve the user experience; then dynamically filters out the cache servers with lower congestion in the first cache server sequence according to the dynamic threshold method to obtain a second cache server sequence. By dynamically calculating the abandonment threshold parameter, the congestion situation in the first cache server sequence is monitored in real time, and the cache servers with better network congestion conditions are selected more accurately, so that the server load is balanced, and the user access response speed and hit rate are improved; finally, the cache sending rate in the second cache server is adjusted according to the packet loss rate, so that the uncongested cache servers can provide a high-speed cache sending rate, and the best cache server with the highest cache sending rate is selected as the server to return the required content of the request. By adjusting the cache sending rate, the high bandwidth utilization rate of the cache server is achieved, the delay of the CDN network is reduced, and the timeliness of content forwarding is improved.

[0013] According to some embodiments of the present invention, the parsing the request to obtain the first cache server sequence of the cache layer includes:

[0014] Perform domain name resolution according to the request to obtain the IP address of the request;

[0015] Obtain the first domain name that has cached the required content corresponding to the IP address from the cache layer; if the number of the first domain names is less than the quantity threshold, sequentially obtain the second domain names closest to the IP address from the cache layer until the number of the first domain names and the second domain names is equal to the quantity threshold;

[0016] Arrange the first domain name or the set of the first domain name and the second domain names in the order of the path of the request from short to long to obtain the first cache server sequence.

[0017] According to some embodiments of the present invention, the calculation formula for the abandonment threshold parameter of each first cache server in the first cache server sequence by the dynamic threshold algorithm includes:

[0018]

[0019] Wherein, T(t) represents the abandonment threshold parameter of the i-th first cache server at time t, β represents the dynamic adjustment parameter, C i represents the total cache capacity of the i-th first cache server, and Q i (t) represents the queue length of the i-th first cache server at time t.

[0020] According to some embodiments of the present invention, the control threshold is obtained by the following method:

[0021] Calculate the network bandwidth corresponding to each of the first cache servers, and the calculation formula for the network bandwidth includes:

[0022]

[0023] Wherein, B t represents the network bandwidth at time t, α represents the exponential filtering factor, and B t-1 represents the network bandwidth in the previous time period before time t;

[0024] Calculate the control threshold corresponding to each of the first cache servers according to the network bandwidth.

[0025] According to some embodiments of the present invention, adjusting the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate includes:

[0026] Calculate the packet loss rate corresponding to each of the second cache servers;

[0027] Compare the packet loss rate with a preset packet loss threshold to obtain a rate control equation corresponding to each of the second cache servers;

[0028] Adjust the cache sending rate of each of the second cache servers according to the rate control equation.

[0029] According to some embodiments of the present invention, the calculation formula for the rate control equation includes:

[0030]

[0031] Wherein, n represents the rate control at the n-th time step, and x i (n) represents the cache sending rate, D represents the round-trip time, p represents the packet loss rate, and p th represents the packet loss threshold, and respectively represent the first speed constant and the second speed constant, and both ε1 and ε2 represent rate change factors.

[0032] According to some embodiments of the present invention, returning the required content of the request through the optimal cache server includes:

[0033] Determine whether the optimal cache server caches the required content of the request;

[0034] If the optimal cache server has cached the required content of the request, directly return the required content to the user; if the optimal cache server has not cached the required content of the request, obtain the required content from the source station and save the required content to the optimal cache server so that the optimal cache server returns the required content to the user.

[0035] In a second aspect, an embodiment of the present invention provides a congestion control system based on a CDN network, including:

[0036] A request acquisition module, configured to acquire a user's request;

[0037] A first cache server sequence calculation module, configured to parse the request to obtain a first cache server sequence of the cache layer; the first cache server sequence is obtained by screening according to the path length of the first cache server;

[0038] A second cache server sequence calculation module, configured to calculate a discard threshold parameter for each of the first cache servers in the first cache server sequence through a dynamic threshold algorithm, and remove the first cache servers with the discard threshold parameter lower than the control threshold from the cache server sequence to obtain a second cache server sequence;

[0039] An optimal cache server calculation module, configured to adjust the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate and obtain the optimal cache server with the highest cache sending rate;

[0040] A required content return module, configured to return the required content of the request through the optimal cache server.

[0041] In a third aspect, an embodiment of the present invention provides an electronic device, including at least one control processor and a memory for communicatively connecting with the at least one control processor; the memory stores instructions executable by the at least one control processor, and the instructions are executed by the at least one control processor so that the at least one control processor can execute the congestion control method based on a CDN network as described in the first aspect.

[0042] In a fourth aspect, an embodiment of the present invention provides a computer storage medium. The computer-readable storage medium stores computer-executable instructions for causing a computer to execute the congestion control method based on a CDN network as described in the first aspect.

[0043] It should be noted that the beneficial effects of the second to fourth aspects of the present invention are the same as those of the congestion control method based on a CDN network in the first aspect, and will not be elaborated here.

[0044] Other features and advantages of the present invention will be described in the following description of the specification, and in part, will be obvious from the description of the specification, or will be understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0046] Figure 1 is a flowchart of a congestion control method based on a CDN network provided by an embodiment of the present invention;

[0047] Figure 2 is a flowchart of analyzing a request to obtain a first cache server sequence of a cache layer provided by an embodiment of the present invention;

[0048] Figure 3 is a flowchart of a control threshold acquisition method provided by an embodiment of the present invention;

[0049] Figure 4 is a flowchart of adjusting the cache sending rate of a second cache server in a second cache server sequence according to a packet loss rate provided by an embodiment of the present invention;

[0050] Figure 5 is a flowchart of returning the required content of a request through an optimal cache server provided by an embodiment of the present invention;

[0051] Figure 6 is a schematic structural diagram of a congestion control system based on a CDN network provided by an embodiment of the present invention;

[0052] Figure 7 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where like or similar reference numerals denote like or similar elements or elements having like or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only for explaining the present invention and should not be construed as limiting the present invention.

[0054] In the description of the present invention, if the first, second, etc. are described, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0055] In the description of the present invention, it should be understood that for the orientation description, such as up, down, etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

[0056] In the description of the present invention, it should be noted that unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0057] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0058] Refer to Figure 1 , in some embodiments of the present invention, a congestion control method based on a CDN network is provided, including:

[0059] Step S100: Obtain a user request.

[0060] Step S200: Parse the request to obtain a first cache server sequence of the cache layer; the first cache server sequence is obtained by screening according to the path lengths of the first cache servers.

[0061] Step S300: Calculate the abandonment threshold parameter of each of the first cache servers in the first cache server sequence through a dynamic threshold algorithm, and remove the first cache servers with abandonment threshold parameters lower than the control threshold from the cache server sequence to obtain a second cache server sequence.

[0062] Step S400: Adjust the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate and obtain the best cache server with the highest cache sending rate.

[0063] Step S500. Return the requested required content through the optimal cache server.

[0064] First, in step S200, the request is parsed to obtain a first cache server sequence with the paths of the requests from short to long according to the request, which can accelerate the speed at which the user opens the requested required content and improve the user experience. Then, in step S300, the cache servers with lower congestion in the first cache server sequence are dynamically screened according to the dynamic threshold method to obtain a second cache server sequence. By dynamically calculating the abandonment threshold parameter and monitoring the congestion situation in the first cache server sequence in real time, the cache server with better network congestion is selected more accurately, enabling server load balancing, improving the user access response speed and hit rate. Finally, in step S400, the cache sending rate in the second cache server is adjusted according to the packet loss rate, so that the non-congested cache server can provide a high-speed cache sending rate. The optimal cache server with the highest cache sending rate is selected as the server to return the requested required content. By adjusting the cache sending rate, the high bandwidth utilization rate of the cache server is achieved, the latency of the CDN network is reduced, and the timeliness of content forwarding is improved.

[0065] Refer to Figure 2 , in some embodiments of the present invention, parsing the request to obtain the first cache server sequence of the cache layer includes:

[0066] Step S201. Perform domain name resolution according to the request to obtain the IP address of the request.

[0067] Step S202. Obtain the first domain name of the required content corresponding to the cached IP address from the cache layer; if the first domain name is less than the quantity threshold, sequentially obtain the second domain names closest to the IP address from the cache layer until the sum of the first domain name and the second domain names is equal to the quantity threshold.

[0068] Step S203. Arrange the first domain name or the collection of the first domain name and the second domain names in ascending order of the path length of the request to obtain the first cache server sequence.

[0069] It should be noted that in the CDN network, if the requested IP address is already cached, the cached IP address will be preferentially selected because there is no need to send a request to the IP address to obtain the required content. Therefore, the first domain name of the cached IP address is preferentially selected, and then the second domain names closest to the IP address are selected. However, for the overall consideration of the CDN network, caching the required content corresponding to the un-cached IP address can also improve the subsequent CDN network speed. Therefore, finally, the first cache server sequence is sorted according to the path length.

[0070] By screening the cached first domain name and the second domain name closest to the IP address, and finally arranging them in ascending order of path length, a first cache server sequence is obtained, which not only ensures the effective use of cache resources, but also gives priority to the cache server with the shortest path to accelerate the access speed and improve the timeliness of the CDN network.

[0071] In some embodiments of the present invention, the calculation formula for the abandonment threshold parameter of each first cache server in the first cache server sequence by the dynamic threshold algorithm includes:

[0072]

[0073] Wherein, T(t) represents the abandonment threshold parameter of the i-th first cache server at time t, β represents the dynamic adjustment parameter, C i represents the total cache capacity of the i-th first cache server, and Q i (t) represents the queue length of the i-th first cache server at time t.

[0074] It should be noted that the dynamic threshold algorithm dynamically adjusts the control threshold according to the system status. The size of the threshold is proportional to the idle buffer resources in the current system, and the buffer resources are fairly allocated among multiple cache servers.

[0075] By calculating the abandonment threshold parameter through the total cache capacity of the first cache server and the queue length of the first cache server, it is possible to determine whether to abandon the cache server according to the system congestion status, provide a digital standard for the selection of the best cache server, improve the utilization rate of the cache space, maximize the utilization of cache resources, and effectively prevent network congestion.

[0076] Refer to Figure 3 , in some embodiments of the present invention, the control threshold is obtained by the following method:

[0077] Step S301: Calculate the network bandwidth corresponding to each first cache server. The calculation formula for the network bandwidth includes:

[0078]

[0079] Wherein, B t represents the network bandwidth at time t, α represents the exponential filtering factor, and B t-1 represents the network bandwidth in the previous time period of time t.

[0080] Step S302: Calculate the control threshold corresponding to each first cache server according to the network bandwidth.

[0081] It should be noted that since the network bandwidth of each cache server may be different, the congestion control thresholds are also different. By determining the control threshold of each cache server based on the network bandwidth, the utilization of cache resources by the cache server can be maximized, and at the same time, each cache server has a specific control threshold to meet personalized requirements.

[0082] The control threshold calculated through the network bandwidth and the weighted exponential filtering factor can effectively solve the impact brought by the suddenness of the link state in the network, and at the same time can take into account the actual congestion situation of the network to ensure that the control threshold can accurately reflect the latest situation of the network.

[0083] Refer to Figure 4 , in some embodiments of the present invention, adjusting the cache sending rate of the second cache server in the second cache server sequence according to the packet loss rate includes:

[0084] Step S401: Calculate the packet loss rate corresponding to each second cache server.

[0085] Step S402: Compare the packet loss rate with a preset packet loss threshold to obtain a rate control equation corresponding to each second cache server.

[0086] Step S403: Adjust the cache sending rate of each second cache server according to the rate control equation.

[0087] In some embodiments of the present invention, the calculation formula of the rate control equation includes:

[0088]

[0089] Among them, n represents the rate control at the nth time step, x i (n) represents the cache sending rate, D represents the round-trip time, p represents the packet loss rate, and p th represents the packet loss threshold, and respectively represent the first speed constant and the second speed constant, and ε1 and ε2 both represent the rate change factors.

[0090] It should be noted that the packet loss threshold is set, and a negative packet loss threshold indicates that the link has not reached saturation. According to the currently obtained packet loss rate value, the rate control is divided into three stages:

[0091] The first stage, that is, the packet loss rate is less than the packet loss threshold, at this time the link has not reached saturation, and the rate adjustment formula is adopted to enable the data stream to quickly utilize the bandwidth when the link has not reached saturation;

[0092] The second stage, that is, the packet loss rate is greater than or equal to the packet loss threshold but less than or equal to 0, at this time the sender adopts an additive increase strategy to adjust the sending rate;

[0093] In the third stage, that is, when the packet loss rate is greater than 0, the link is overloaded at this time, and the sender adopts a multiplicative decrease strategy to adjust the sending rate. The multiplicative decrease factor is a function of the packet loss rate.

[0094] Through the three-stage rate control, it is possible to quickly achieve a high bandwidth utilization rate, provide a high-speed cache server for the CDN network, improve the timeliness of the CDN network, and at the same time improve the user experience.

[0095] Refer to Figure 5 , in some embodiments of the present invention, the required content of the request is returned by the optimal cache server, including:

[0096] Step S501: Determine whether the optimal cache server caches the required content of the request.

[0097] Step S502: If the optimal cache server has cached the required content of the request, directly return the required content to the user; if the optimal cache server has not cached the required content of the request, obtain the required content from the source station and save the required content to the optimal cache server so that the optimal cache server returns the required content to the user.

[0098] It should be noted that when accessing the actual resource through the IP, if the resource is not cached on the CDN, the resource will be requested from the source station and cached on the CDN node. When the user accesses it next time, the CDN node will have the cache of the corresponding resource. Therefore, in this embodiment, the strategy of the CDN network is also adopted to ensure obtaining the required content nearby, reduce network congestion, and improve the user access response speed and hit rate.

[0099] Refer to Figure 6 , an embodiment of the present invention further provides a congestion control system based on a CDN network, including a request acquisition module 1001, a first cache server sequence calculation module 1002, a second cache server sequence calculation module 1003, an optimal cache server calculation module 1004, and a required content return module 1005, where:

[0100] The request acquisition module 1001 is used to acquire the user's request.

[0101] The first cache server sequence calculation module 1002 is used to parse the request to obtain the first cache server sequence of the cache layer; the first cache server sequence is screened according to the path length of the first cache server.

[0102] The second cache server sequence calculation module 1003 is configured to calculate the abandonment threshold parameter of each of the first cache servers in the first cache server sequence through a dynamic threshold algorithm, remove the first cache servers with abandonment threshold parameters lower than the control threshold from the cache server sequence, and obtain a second cache server sequence.

[0103] The optimal cache server calculation module 1004 is configured to adjust the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate and obtain the optimal cache server with the highest cache sending rate.

[0104] The required content return module 1005 is configured to return the requested required content through the optimal cache server.

[0105] It should be noted that since a congestion control system based on a CDN network in this embodiment and the above-mentioned congestion control method based on a CDN network are based on the same inventive concept, the corresponding content in the method embodiment is equally applicable to the device embodiment of the present invention and will not be elaborated here.

[0106] Reference Figure 7 , another embodiment of the present invention further provides an electronic device. The electronic device 6000 can be any type of intelligent terminal, such as a mobile phone, a tablet computer, a personal computer, etc.

[0107] Specifically, the electronic device 6000 includes: one or more control processors 6001 and a memory 6002. Figure 7 Taking one control processor 6001 and one memory 6002 as an example, the control processor 6001 and the memory 6002 can be connected through a bus or other means. Figure 7 Taking the connection through a bus as an example.

[0108] The memory 6002, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as program instructions / modules corresponding to an electronic device in an embodiment of the present invention.

[0109] The control processor 6001 executes various functional applications and data processing of a congestion control method based on a CDN network by running the non-transitory software programs, instructions, and modules stored in the memory 6002, that is, implements a congestion control method based on a CDN network in the above method embodiment.

[0110] The memory 6002 may include a program storage area and a data storage area. The program storage area may store an operating system and application programs required for at least one function. The data storage area may store data created by using a congestion control method based on a CDN network, etc. In addition, the memory 6002 may include high-speed random access memory and may also include non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory 6002 may optionally include a memory remotely provided with respect to the control processor 6001, and these remote memories may be connected to the electronic device 6000 through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0111] When one or more modules are stored in the memory 6002 and executed by the one or more control processors 6001, a congestion control method based on a CDN network in the above method embodiments is executed, for example, the method steps described above are executed. Figures 1 to 5 of the method steps.

[0112] As a non-transitory computer-readable storage medium, the memory can be used to store non-transitory software programs and non-transitory computer-executable programs. In addition, the memory may include high-speed random access memory and may also include non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory may optionally include a memory remotely provided with respect to the processor, and these remote memories may be connected to the processor through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0113] It should be noted that since an electronic device in this embodiment and a congestion control method based on a CDN network described above are based on the same inventive concept, the corresponding content in the method embodiments also applies to the device embodiments in this case, and will not be elaborated here.

[0114] An embodiment of the present invention further provides a computer-readable storage medium storing computer-executable instructions for executing: a congestion control method based on a CDN network as in the above embodiments.

[0115] It should be noted that since a computer-readable storage medium in this embodiment and a congestion control method based on a CDN network described above are based on the same inventive concept, the corresponding content in the method embodiments also applies to the device embodiments in this case, and will not be elaborated here.

[0116] Those of ordinary skill in the art will understand that all or some of the steps and systems disclosed in the above methods can be implemented as software, firmware, hardware, and their appropriate combinations. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or can be implemented as hardware, or can be implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing data, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassettes, tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired data and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that a communication medium typically includes computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and can include any data delivery medium.

[0117] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0118] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A congestion control method based on the CDN network, characterized in that The congestion control method based on the CDN network includes: Obtain the request of the user; Parse the request to obtain the first cache server sequence of the cache layer; the first cache server sequence is obtained by screening according to the path length of the first cache server; Calculate the abandonment threshold parameter of each first cache server in the first cache server sequence through the dynamic threshold algorithm, and remove the first cache servers with the abandonment threshold parameter lower than the control threshold from the cache server sequence to obtain the second cache server sequence; Adjust the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate and obtain the best cache server with the highest cache sending rate; Return the required content of the request through the best cache server; The calculation formula for calculating the abandonment threshold parameter of each first cache server in the first cache server sequence through the dynamic threshold algorithm includes: Among them, T i (t) represents the abandonment threshold parameter of the i-th first cache server at time t, β represents the dynamic adjustment parameter, C i represents the total cache capacity of the i-th first cache server, Q i (t) represents the queue length of the i-th first cache server at time t; The control threshold is obtained through the following method: Calculate the network bandwidth corresponding to each first cache server, and the calculation formula of the network bandwidth includes: Among them, B t represents the network bandwidth at time t, α represents the exponential filtering factor, and B t-1 represents the network bandwidth in the previous time period before time t; Calculate the control threshold corresponding to each first cache server according to the network bandwidth; The adjustment of the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate includes: Calculate the packet loss rate corresponding to each second cache server; Compare the packet loss rate with a preset packet loss threshold to obtain the rate control equation corresponding to each second cache server; Adjust the cache sending rate of each second cache server according to the rate control equation; The calculation formula of the rate control equation includes: Among them, n represents the rate control at the nth time step, and x i (n) represents the cache sending rate, D represents the round-trip time, p represents the packet loss rate, and p th represents the packet loss threshold, and represent the first speed constant and the second speed constant respectively. Both ε1 and ε2 represent rate change factors.

2. The congestion control method based on the CDN network according to claim 1, wherein The parsing of the request to obtain the first cache server sequence of the cache layer includes: Perform domain name resolution according to the request to obtain the IP address of the request; Obtain the first domain name that has cached the required content corresponding to the IP address from the cache layer; if the number of the first domain names is less than the quantity threshold, sequentially obtain the second domain names closest to the IP address from the cache layer until the sum of the number of the first domain names and the second domain names is equal to the quantity threshold; Arrange the first domain name or the collection of the first domain name and the second domain names in ascending order of the path length of the request to obtain the first cache server sequence.

3. The congestion control method based on the CDN network according to claim 1, characterized in that, The return of the required content of the request through the best cache server includes: Judge whether the best cache server has cached the required content of the request; If the best cache server has cached the required content of the request, directly return the required content to the user; if the best cache server has not cached the required content of the request, obtain the required content from the source station and save the required content to the best cache server so that the best cache server returns the required content to the user.

4. A congestion control system based on a CDN network, characterized in that, The congestion control system based on the CDN network includes: A request acquisition module for acquiring the request of the user; The first cache server sequence calculation module is used to parse the request to obtain the first cache server sequence of the cache layer; the first cache server sequence is obtained by screening according to the path lengths of the first cache servers. The second cache server sequence calculation module is used to calculate the abandonment threshold parameters of each of the first cache servers in the first cache server sequence through a dynamic threshold algorithm, remove the first cache servers with abandonment threshold parameters lower than the control threshold from the cache server sequence to obtain a second cache server sequence. The optimal cache server calculation module is used to adjust the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate and obtain the optimal cache server with the highest cache sending rate. The required content return module is used to return the required content of the request through the optimal cache server. The calculation formula for calculating the abandonment threshold parameters of each of the first cache servers in the first cache server sequence through the dynamic threshold algorithm includes: Among them, T i (t) represents the abandonment threshold parameter of the i-th first cache server at time t, β represents the dynamic adjustment parameter, C i represents the total cache capacity of the i-th first cache server, Q i (t) represents the queue length of the i-th first cache server at time t; The control threshold is obtained through the following method: Calculate the network bandwidth corresponding to each of the first cache servers, and the calculation formula of the network bandwidth includes: Among them, B t represents the network bandwidth at time t, α represents the exponential filtering factor, and B t-1 represents the network bandwidth in the previous time period before time t; Calculate the control threshold corresponding to each of the first cache servers according to the network bandwidth. Adjusting the cache sending rate of the second cache servers in the second cache server sequence according to the packet loss rate includes: Calculate the packet loss rate corresponding to each of the second cache servers. Compare the packet loss rate with a preset packet loss threshold to obtain a rate control equation corresponding to each of the second cache servers. Adjust the cache sending rate of each of the second cache servers according to the rate control equation. The calculation formula of the rate control equation includes: Among them, n represents the rate control at the nth time step, and x i (n) represents the cache sending rate, D represents the round-trip time, p represents the packet loss rate, and p th represents the packet loss threshold, and represent the first speed constant and the second speed constant respectively, and both ε1 and ε2 represent the rate change factors.

5. An electronic device, characterized in that: It includes at least one control processor and a memory for communicatively connecting with the at least one control processor; the memory stores instructions executable by the at least one control processor, and the instructions are executed by the at least one control processor so that the at least one control processor can execute the congestion control method based on the CDN network according to any one of claims 1 to 3.

6. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to cause a computer to execute the congestion control method based on the CDN network according to any one of claims 1 to 3.

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