CN106209952A - Service node distribution method, device, CDN management server and system - Google Patents

Abstract

The invention provides a service node allocation method, device, CDN management server and system. Wherein, the method includes: receiving a login request from a user terminal for requesting access to the multimedia service system; calculating an optimal service node among service nodes of a content distribution network (CDN) that provides services for the user terminal according to a preset algorithm; The signaling address of the optimal serving node is sent to the user terminal. The invention solves the problem of high load pressure on the CDN request routing server and reduces the load pressure on the CDN request routing server.

Description

Service node allocation method, device, CDN management server and system

technical field

The present invention relates to the communication field, in particular to a service node allocation method, device, CDN management server and system.

Background technique

With the rapid development of broadband networks, many new Internet services have been greatly spawned, such as Internet Protocol Television (IPTV for short) services, Internet video, Over The Top (OTT for short), etc. business. At the same time, these multimedia services have extremely high requirements on bandwidth. With the rapid development of multimedia services, bandwidth is being swallowed up rapidly. If there is no Content Delivery Network (CDN for short) for these multimedia services, each user needs to have a high-bandwidth link from the access side to the backbone network, which is costly and difficult to guarantee quality.

In a multimedia business system, multiple media servers (i.e. nodes) are usually used to form a CDN to provide services to end users. Multiple nodes are distributed hierarchically, and a node that provides services is designated for each user; the CDN caches content in different locations and passes the load. Technologies such as balancing redirect user requests to the optimal cache server (such as the nearest cache server) to obtain content, so that users can watch content on their own nodes. A request routing (Request Router, RR for short) mechanism of content service is one of the key factors in CDN network planning. In order to achieve global load balancing, the CDN RR server uses redirection scheduling technology to schedule user requests to the optimal server.

During the research process, the inventor found that with the rapid growth of the number of end users and nodes, the load pressure on the CDN RR server will also increase. How to reduce the load pressure on the CDN RR has become a new problem for the CDN network.

Aiming at the problem of high load pressure on CDN RR servers in related technologies, no effective solution has been proposed yet.

Contents of the invention

In order to solve the above technical problems, the present invention provides a service node allocation method, device, CDN management server and system.

According to one aspect of the present invention, a method for allocating service nodes is provided, including: receiving a login request from a user terminal for requesting access to a multimedia service system; The optimal service node that provides the service for the user terminal; sending the signaling address of the optimal service node to the user terminal.

Preferably, after receiving the login request, the method further includes: determining that the access mode requested by the user terminal carried in the login request is a non-CDN RR access mode.

Preferably, after it is determined that the access mode requested by the user terminal carried in the login request is the non-CDNRR access mode, or after receiving the user terminal request to access the multimedia service system After the login request, the method further includes: judging whether the load of the CDN RR server is lower than a first preset value; if it is judged that the load of the CDN RR server is lower than the first preset value, setting the Send the signaling address of the CDN RR server to the user terminal.

Preferably, calculating the optimal service node serving the user terminal among the service nodes of the CDN includes: calculating The optimal service node that provides services for the user terminal among the service nodes of the CDN.

Preferably, after receiving the login request, the method further includes: determining that the access mode requested by the user terminal carried in the login request is a CDN RR access mode.

Preferably, after determining that the access mode requested by the user terminal carried in the login request is the CDNRR access mode, or after receiving the login request for accessing the multimedia service system by the user terminal After the request, the method further includes: judging whether the load of the CDN RR server is higher than a second preset value, or whether the CDN RR server is faulty; after judging that the load of the CDN RR server is not higher than the second preset value Two preset values, or, if the CDN RR server is not faulty, send the signaling address of the CDN RR server to the user terminal.

Preferably, calculating the optimal service node serving the user terminal among the service nodes of the CDN includes: when it is determined that the load of the CDN RR server is higher than the second preset value, or the CDN In the case of failure of the RR server, the optimal service node that provides the service for the user terminal among the service nodes of the CDN is calculated.

According to another aspect of the present invention, a device for allocating service nodes is also provided, including: a receiving module, configured to receive a login request from a user terminal for requesting access to a multimedia service system; a computing module, configured to, according to a preset algorithm, Computing an optimal service node that provides services for the user terminal among service nodes of a content distribution network (CDN); a first sending module, configured to send the signaling address of the optimal service node to the user terminal.

Preferably, the device further includes: a first determining module, configured to determine that the access mode requested by the user terminal carried in the login request is a non-CDN RR access mode.

Preferably, the device further includes: a first judging module, configured to judge whether the load of the CDN RR server is lower than a first preset value; a second sending module, configured to judge that the load of the CDN RR server is lower than In the case of the first preset value, sending the signaling address of the CDN RR server to the user terminal.

Preferably, the calculation module is configured to calculate the service node serving the user terminal in the CDN in the case of judging that the load of the CDN RR server is not lower than the first preset value. Optimal service node.

Preferably, the device further includes: a second determining module, configured to determine that the access mode requested by the user terminal carried in the login request is a CDN RR access mode.

Preferably, the device further includes: a second judgment module, used to judge whether the load of the CDN RR server is higher than a second preset value, or whether the CDN RR server is faulty; a third sending module, used to judge whether the load of the CDN RR server is higher than the second preset value; The load to the CDN RR server is not higher than the second preset value, or, if the CDN RR server is not faulty, send the signaling address of the CDN RR server to the user terminal.

Preferably, the calculation module is configured to calculate the CDN RR server load of the CDN RR server is higher than the second preset value, or the CDN RR server fails. The optimal service node that provides the service for the user terminal.

According to another aspect of the present invention, a CDN management server is also provided, including: the above device for assigning service nodes.

According to another aspect of the present invention, a multimedia service system is also provided, including: the above-mentioned CDN management server, CDN RR server, service node and user terminal, wherein the CDN RR server is used to send the login request of the user terminal Redirect to the optimal service node among the service nodes; the service node is used to provide multimedia services.

According to the present invention, the login request used by the user terminal to request access to the multimedia service system is received; according to the preset algorithm, the optimal service node that provides services for the user terminal among the service nodes of the content distribution network (CDN) is calculated; the optimal The method of sending the signaling address of the service node to the user terminal solves the problem of heavy load pressure on the CDN RR server and reduces the load pressure on the CDN RR server.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is a flow chart of a method for assigning service nodes according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a service node allocation device according to an embodiment of the present invention;

FIG. 3 is a first schematic diagram of a preferred structure of a service node allocation device according to an embodiment of the present invention;

FIG. 4 is a schematic diagram 2 of a preferred structure of a service node allocation device according to an embodiment of the present invention;

FIG. 5 is a third preferred structural diagram of a service node allocation device according to an embodiment of the present invention;

FIG. 6 is a fourth schematic diagram of a preferred structure of a service node allocation device according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a multimedia service system according to an embodiment of the present invention;

Fig. 8 is a schematic structural diagram of a multimedia service system according to a preferred embodiment of the present invention;

Fig. 9 is a flowchart of a method for requesting a multimedia access service according to a preferred embodiment of the present invention.

detailed description

Hereinafter, the present invention will be described in detail with reference to the drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

An embodiment of the present invention provides a service node allocation method. FIG. 1 is a flowchart of a service node allocation method according to an embodiment of the present invention. As shown in FIG. 1 , the process includes the following steps:

Step S102, receiving a login request from the user terminal for requesting access to the multimedia service system;

Step S104, according to a preset algorithm, calculate the optimal service node that provides services for the user terminal among the service nodes of the CDN;

Step S106, sending the signaling address of the optimal serving node to the user terminal.

Through the above steps, in the content distribution network, the method of directly calculating the optimal service node for the user terminal and sending the signaling address of the optimal service node to the user terminal is adopted, so that the user terminal can, according to the received signaling address, and Acquire multimedia services directly through the optimal service node. It can be seen that by adopting the above steps, the redirection of the login request can no longer be performed through the CDN RR server, which solves the problem of heavy load pressure on the CDN RR server and reduces the load pressure on the CDN RR server. In addition, since the user terminal can obtain the multimedia service directly from the optimal service node without being redirected by the CDN RR server, the interaction process is reduced, thereby improving the processing efficiency of the content distribution network.

Preferably, the above steps can be executed by the CDN management server, or by a module belonging to the CDN management server. The CDN management server is the management center of the CDN network.

In this embodiment, the embodiment of the present invention will be described with the CDN management server as the execution subject.

Preferably, the CDN management server may determine whether to process the login request of the user terminal in steps S104 to S106 as required. For example, the CDN management server may instruct the user terminal to adopt the CDN RR access mode when the load of the CDN RR server is low, for example: the CDN management server judges whether the load of the CDN RR server is lower than the first preset value; When the load to the CDN RR server is lower than the first preset value, the signaling address of the CDN RR server is sent to the user terminal. Preferably, after receiving the signaling address of the CDN RR server, the user terminal uses the CDN RR access mode to access.

Preferably, when the CDN management server determines that the load of the CDN RR server is not lower than the first preset value, then execute steps S104 to S106, so that the user terminal continues to use the non-CDN RR access mode for access.

It can be seen that, through the above method, the user terminal can use the CDN RR access mode or the non-CDN RR access mode to access according to the load condition of the CDN RR server.

In some embodiments, the method of selecting the access mode through the user terminal may also be adopted. In this case, the user's login request may carry the access mode selected by the user terminal. For example, in the case that the access mode selected by the user terminal is the non-CDN RR access mode, after step S102, the CDN management server may also analyze the login request. If the access mode is a non-CDNRR access mode, step S104 is performed.

Preferably, when it is resolved that the user terminal adopts a non-CDN RR access mode, the CDN management server can still flexibly specify the user terminal access mode according to the load of the CDN RR.

Preferably, the CDN management server may determine whether to process the login request of the user terminal in steps S104 to S106 as required. For example, the CDN management server judges whether the load of the CDN RR server is higher than the second preset value, or whether the CDN RR server fails; If there is no failure, the signaling address of the CDN RR server is sent to the user terminal. Preferably, after receiving the signaling address of the CDN RR server, the user terminal uses the CDN RR access mode to access.

Preferably, when the CDN management server judges that the load of the CDN RR server is higher than the second preset value, or that the CDN RR server fails, step S104 to step S106 are executed, so that the user terminal continues to use non-CDN RR access mode to access.

Preferably, when it is resolved that the user terminal adopts the CDN RR access mode, the CDN management server can still flexibly specify the user terminal access mode according to the load of the CDN RR.

In this embodiment, a device for allocating service nodes is also provided, which is used to implement the above embodiments and preferred implementation modes. What has been described will not be repeated. The modules involved in the device will be described below. As used below, the term "module" may be a combination of software and/or hardware that realizes a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementations in hardware, or a combination of software and hardware are also possible and contemplated.

Fig. 2 is a schematic structural diagram of a service node allocation device according to an embodiment of the present invention. As shown in Fig. 2, the device includes: a receiving module 22, a computing module 24 and a first sending module 26, wherein the receiving module 22 is used to receive The user terminal is used to request a login request for accessing the multimedia service system; the calculation module 24 is coupled to the receiving module 22, and is used to calculate the optimal service node among the service nodes of the CDN that provides services for the user terminal according to a preset algorithm; the first The sending module 26 is coupled to the computing module 24 and configured to send the signaling address of the optimal serving node to the user terminal.

Fig. 3 is a schematic diagram of a preferred structure of a service node allocation device according to an embodiment of the present invention. As shown in Fig. 3, preferably, the device further includes: a first determining module 32, coupled between the receiving module 22 and the computing module 24, It is used to determine that the access mode requested by the user terminal carried in the login request is a non-CDN RR access mode.

Fig. 4 is a schematic diagram 2 of a preferred structure of a service node allocation device according to an embodiment of the present invention. As shown in Fig. 4, preferably, the device further includes: a first judging module 42, coupled to the first determining module 32 or the receiving module 22, And coupled to the calculation module 24, for judging whether the load of the CDN RR server is lower than the first preset value; the second sending module 44, coupled to the first judging module 42, for judging that the load of the CDN RR server is lower than In the case of the first preset value, the signaling address of the CDN RR server is sent to the user terminal.

Preferably, the calculation module 24 is configured to calculate the optimal service node among the service nodes of the CDN that provides services for the user terminal when it is determined that the load of the CDN RR server is not lower than the first preset value.

FIG. 5 is a schematic diagram of a preferred structure of a service node allocation device according to an embodiment of the present invention. As shown in FIG. , used to determine that the access mode requested by the user terminal carried in the login request is the CDN RR access mode.

Fig. 6 is a schematic diagram 4 of a preferred structure of a service node allocation device according to an embodiment of the present invention. As shown in Fig. 6, preferably, the device further includes: a second judging module 62, coupled to the second determining module 52 or the receiving module 22, And coupled to the calculation module 24, used to determine whether the load of the CDN RR server is higher than the second preset value, or whether the CDN RR server fails; the third sending module 64, coupled to the second determination module 62, used to determine whether The load to the CDN RR server is not higher than the second preset value, or, if the CDN RR server is not faulty, the signaling address of the CDN RR server is sent to the user terminal.

Preferably, the calculation module 24 is configured to calculate the optimal service for the user terminal in the service node of the CDN when it is determined that the load of the CDN RR server is higher than the second preset value, or that the CDN RR server fails node.

This embodiment also provides a CDN management server, including: the above device for assigning service nodes.

This embodiment also provides a multimedia service system. FIG. 7 is a schematic structural diagram of a multimedia service system according to an embodiment of the present invention. As shown in FIG. 7, the multimedia service system includes: a CDN management server 72, a CDN RR server 74, The service node 76 and the user terminal 78, wherein, the CDN RR server 72 is used to redirect the login request of the user terminal to the optimal service node among the service nodes; the service node 76 is used to provide multimedia services.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, each unit may exist separately physically, or two or more units may be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

In order to make the description of the embodiments of the present invention clearer, the following describes and illustrates in conjunction with preferred embodiments.

This preferred embodiment provides a system and method for improving user access to a multimedia service system, and the method relates to multimedia service fields in telecommunication networks such as IPTV, mobile streaming media system, and mobile phone download.

The purpose of the preferred embodiment of the present invention is to provide a new user access mode to reduce the load pressure of the CDN RR server in a large-scale multimedia service system of end users (ie, user terminals) and nodes (ie, service nodes) In this way, the robustness of the CDN in providing multimedia services to users is improved.

In this preferred embodiment, a channel is established between the CDN management module (equivalent to the above-mentioned CDN management server or the above-mentioned service node distribution device) and each CDN node and managed; the channel is established between the CDN management module and the CDN RR and CDN nodes can regularly report their node performance status to the CDN management module; CDN RR can regularly report heartbeat messages to the CDN management module; the CDN management module can regularly forward the status information of each node of the CDN to the CDN RR;

The user terminal (such as a set-top box STB) initiates a login request to the CDN management module, and the CDN management module selects the corresponding service node signaling address or the signaling address of the CDN RR to the user according to the user access mode;

If the CDN RR access mode is selected, the CDN management module will judge the running status of the CDN RR, and when the status is normal, it will return the signaling address of the CDN RR to the user, and each time the user initiates a service request, the request will be sent to the CDN RR, CDN RR selects a suitable service node to provide services to users. If the CDN RR status is abnormal, select the non-CDN RR access mode; if the non-CDN RR access mode is selected, the CDN management module selects the optimal service node according to the algorithm and returns its signaling address to the user, and the user directly logs in to the The service is performed on the node, and the subsequent service is directly performed on the node.

In this way, users can better access the multimedia service system for services. For example, using the newly added user access mode, on the one hand, it can reduce the load pressure of the CDN RR; Users provide access services to ensure the robustness of the system. At the same time, the newly added user access mode directly connects users to the best server for services, and then directly performs services on this server, which can improve the speed of users' access to media services.

The preferred embodiment of the present invention also provides an improved user access multimedia service system for implementing the above method, the system includes a CDN node, a CDN management module, and a CDN RR module (equivalent to the above-mentioned CDN RR server);

CDN node: a server used to store content and provide content services. For content, a CDN node can be used as a source node and a target node, and the content is distributed from the source node to the target node;

CDN management module: used to manage the status of CDN nodes and CDN RR and handle various multimedia service requests;

CDN RR module: used to process user access to the multimedia service system; according to the type of service requested by the user, use the redirection scheduling technology to dispatch the user's request to the optimal server.

The method for improving the multimedia access service request of the user in the multimedia service system by using the newly added user access mode provided by the preferred embodiment of the present invention includes the following steps:

Step 1, the CDN management module establishes a channel with each CDN node, and manages the CDN node and CDN RR and processes various multimedia service requests; the CDN target node regularly reports its node status information to the CDN management module; the CDN RR module regularly Report its heartbeat message to the CDN management module;

Step 2, the user terminal device initiates a user login request to the CDN management module, and the CDN management module judges the user access mode; if it is the CDN RR user access mode, judges whether the CDN RR status is normal, and if normal, returns the information of the CDN RR The address is given to the user, and the process ends. If the CDN RR status is abnormal, the user will switch to non-CDN RR mode access; if it is a non-CDN RR mode user access mode, the CDN management module will select the current optimal The signaling address of the service node to the user;

Step 3, the user terminal device initiates a multimedia service request according to the returned address. If the returned address is the signaling address of the service node, the user directly performs multimedia services on the node; if it is the address of the CDN RR, the user sends the The above-mentioned CDN RR management module initiates a multimedia service request, and the CDN RR management module dispatches the user's request to a corresponding service node for multimedia service by using redirection scheduling technology.

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings.

Fig. 8 is a schematic structural diagram of a multimedia service system according to a preferred embodiment of the present invention, which is a modified form of Fig. 7 . As shown in FIG. 8 , this implementation provides a system for improving user access to a multimedia service system for service, including a CDN management server, multiple node servers, a CDN RR management server, and a user terminal device.

In the implementation process, preferably, the transmission control protocol (TCP) can be used to establish a channel between the CDN management module and the CDN node; the CDN management module and the CDN RR module adopt the TCP protocol to establish a channel; the user terminal equipment adopts the hypertext transfer protocol ( HTTP) to access the CDN management module; the user terminal equipment interacts with the CDN node and the CDN RR through the real-time streaming protocol (RTSP).

Fig. 9 is a flowchart of a method for requesting a multimedia access service according to a preferred embodiment of the present invention. As shown in Fig. 9, the process includes the following steps:

Step S901, the CDN node regularly sends node performance data to the CDN management module;

Step S902, the CDN management module forwards the CDN node performance data to the CDN RR module;

Step S903, the CDN RR regularly sends a heartbeat message to the CDN management module;

Step S904, the user terminal (for example, STB) initiates a user login access request (equivalent to the above login request) to the CDN management module;

Step S905, the CDN management module determines the address of the CDN RR (that is, the signaling address of the CDN RR) according to the user's access mode, or determines the address of the optimal CDN service node (that is, the address of the optimal CDN service node) according to the optimal algorithm. signaling address);

Step S906, the CDN management module returns the service address of the login access request to the user (that is, the address of the CDN RR or the address of the optimal CDN service node);

Method 1, in the case of obtaining a CDN service node through a CDN RR

Step S907, the user initiates a multimedia service request;

Step S908, the CDN RR returns the address of the optimal CDN service node according to the redirection scheduling technology and the load balancing technology;

Step S909, the CDN RR returns the address of the CDN service node to the user;

Method 2, in the case of obtaining multimedia services directly through the optimal CDN service node

Step S910, the user initiates a multimedia service request;

In step S911, the CDN service node provides multimedia services for users.

It should be noted that, in this preferred embodiment, the communication protocols used between the various modules may use different interaction protocols during implementation. The system and method for improving user access to the multimedia service system provided by the preferred embodiment of the present invention by utilizing the innovative architecture of the new user access mode can be extended to other service fields.

To sum up, through the above-mentioned embodiments and preferred embodiments of the present invention, a new user access mode is added, and the management platform is used to bind the user to the optimal node for service, and after the user logs in to the node, Subsequent requests for services do not need to initiate redirection requests, and services can be directly performed on the binding node, thereby improving the speed of users' access to multimedia services. In addition, the management platform can flexibly configure the user's access strategy, which can share the pressure of the redirection server, and use the newly added access mode (user access mode) to continue to provide access for users when the redirection server cannot provide services. Serve.

In another embodiment, software is also provided, and the software is used to implement the technical solutions described in the above embodiments and preferred implementation manners.

In another embodiment, there is also provided a storage medium, in which the software is stored, the storage medium includes but not limited to: optical discs, floppy disks, hard disks, rewritable memories, and the like.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned present invention can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed in a network formed by multiple computing devices Alternatively, they may be implemented in program code executable by a computing device so that they may be stored in a storage device to be executed by a computing device, and in some cases in an order different from that shown here The steps shown or described are carried out, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps among them are fabricated into a single integrated circuit module for implementation. As such, the present invention is not limited to any specific combination of hardware and software.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (16)

1. A service node distribution method, characterized in that comprising: receiving a login request from a user terminal for requesting access to the multimedia service system; According to a preset algorithm, calculate an optimal service node that provides services for the user terminal among the service nodes of the content distribution network CDN; Sending the signaling address of the optimal serving node to the user terminal. 2. The method according to claim 1, characterized in that, after receiving the login request, the method further comprises: Determining that the access mode requested by the user terminal carried in the login request is a non-CDN request routing RR access mode. 3. The method according to claim 1 or 2, wherein after determining that the access mode requested by the user terminal carried in the login request is the non-CDN RR access mode, or after receiving After the login request of the user terminal for requesting access to the multimedia service system, the method further includes: judging whether the load of the CDN RR server is lower than a first preset value; When it is determined that the load of the CDN RR server is lower than the first preset value, sending the signaling address of the CDN RR server to the user terminal. 4. The method according to claim 3, wherein the calculation of the optimal service node serving the user terminal among the service nodes of the CDN comprises: In a case where it is determined that the load of the CDN RR server is not lower than the first preset value, calculating the optimal service node serving the user terminal among the service nodes of the CDN. 5. The method according to claim 1, characterized in that, after receiving the login request, the method further comprises: Determine that the access mode requested by the user terminal carried in the login request is a CDN RR access mode. 6. The method according to claim 1 or 5, wherein after determining that the access mode requested by the user terminal carried in the login request is the CDN RR access mode, or after receiving the After the login request of the user terminal for requesting access to the multimedia service system, the method further includes: Judging whether the load of the CDN RR server is higher than a second preset value, or whether the CDN RR server is faulty; When it is determined that the load of the CDN RR server is not higher than the second preset value, or that the CDN RR server is not faulty, sending the signaling address of the CDN RR server to the user terminal . 7. The method according to claim 6, wherein the calculation of the optimal service node serving the user terminal among the service nodes of the CDN comprises: When it is judged that the load of the CDN RR server is higher than the second preset value, or that the CDN RR server is faulty, calculate the optimal service node for the user terminal in the CDN service node. 8. A service node allocation device, characterized in that it comprises: A receiving module, configured to receive a login request from a user terminal for requesting access to the multimedia service system; A calculation module, configured to calculate the optimal service node that provides services for the user terminal among the service nodes of the content distribution network CDN according to a preset algorithm; A first sending module, configured to send the signaling address of the optimal serving node to the user terminal. 9. The device according to claim 8, further comprising: The first determining module is configured to determine that the access mode requested by the user terminal carried in the login request is a non-CDN request routing RR access mode. 10. The device according to claim 8 or 9, wherein the device further comprises: A first judging module, configured to judge whether the load of the CDN RR server is lower than a first preset value; The second sending module is configured to send the signaling address of the CDN RR server to the user terminal when it is determined that the load of the CDN RR server is lower than the first preset value. 11. The device according to claim 10, wherein the calculation module is configured to calculate the service node of the CDN when it is determined that the load of the CDNRR server is not lower than the first preset value The optimal service node that provides services for the user terminal. 12. The device according to claim 8, further comprising: The second determining module is configured to determine that the access mode requested by the user terminal carried in the login request is a CDN RR access mode. 13. The device according to claim 8 or 12, characterized in that the device further comprises: The second judging module is used to judge whether the load of the CDN RR server is higher than a second preset value, or whether the CDN RR server is faulty; The third sending module is configured to send the signaling of the CDN RR server when it is determined that the load of the CDN RR server is not higher than the second preset value, or that the CDN RR server is not fault The address is sent to the user terminal. 14. The device according to claim 13, wherein the calculation module is configured to determine that the load of the CDN RR server is higher than the second preset value, or that the CDN RR server fails In this case, the optimal service node that provides the service for the user terminal among the service nodes of the CDN is calculated. 15. A CDN management server, characterized by comprising: the device for allocating service nodes according to any one of claims 8 to 14. 16. A multimedia service system, characterized in that it comprises: CDN management server, CDN RR server, service node and user terminal as claimed in claim 15, wherein, The CDN RR server is configured to redirect the login request of the user terminal to the optimal service node among the service nodes; The service node is used to provide multimedia services.