WO2009100672A1 - Processing method when content route being abnormity, content route function device and system - Google Patents

Abstract

A processing method when content route being abnormity, a content route function device and system, belong to the communication field. The method includes the steps: the content route function transmits a content service request to a media station with the requested content, when a certainty response to the content service request is not received, the content route function reselects a media station with the requested content except the said media station, and sends the content service request to the reselected media station. The content route function device includes a transmitting module and an abnormity processing module. The system includes a content route function device. In the invention, when abnormity appears, a new media station is reselected, and the content service request of a terminal is finished by the reselected media station, thus the service quality is improved.

Description

 Processing method when content routing is abnormal, content routing function device and system

 The present invention relates to the field of communications, and in particular, to a method, a content routing function device, and a system for processing content exceptions. Say

Background technique

 The streaming media service or IPTV (IP Television) service is a new service. The streaming media service utilizes streaming technology to transmit multimedia files, including video and audio files, on a packet switched network. This content can be played immediately without having to download it completely. The key technology for streaming media implementation is streaming technology, and streaming books.

Transmission technology is a network transmission technology that processes continuous video and audio information and puts it on the server, allowing users to watch and listen while downloading, without having to wait for the entire file to be downloaded to their own machine.

 IMS (IP Multimedia Subsystem) is a subsystem of multimedia services, including CSCF (Call Session Control Function), MGCF (Media Gateway Control Function), MRF ( Functional entities such as the Media Resource Function (media resource function), mainly adopting SIP (Session Initiation Protocol) and Diameter protocol, belong to the upper-layer control subsystem, and have nothing to do with the specific access technology. The ideal solution and direction of development.

 The SIP protocol is an application layer control protocol that can be used to establish, modify, and terminate multimedia sessions (or conferences), such as Internet telephony. The SIP protocol also supports inviting participants to participate in existing sessions, such as multiparty conferences.

 The IPTV service provided by the IMS-based architecture can fully utilize the existing mechanisms of registration, authentication, routing, session control and establishment, service triggering, charging, and end-to-end QoS (Quality of Service) guarantee in the IMS network. Users provide streaming services and multimedia services that integrate streaming media and real-time session services.

 CDN (Content Delivery/Distribution Network) is augmented with the scale of the website. Appropriate CDN deployment enables hot-spot web pages, images, etc. to be cached by CDN nodes close to users. When the user requests content, it can be obtained from these CDN cache nodes in the near future, so that the content can be quickly delivered to the user, thereby improving the user experience and reducing the congestion of the backbone network.

 In the process of implementing the present invention, the inventors have found that the prior art described above has at least the following problems:

Under the existing CDN mechanism, if the selected media node has no content or other abnormal conditions, there is no corresponding The processing method completes the content service request of the terminal, and the request of the terminal fails. Summary of the invention

 In order to complete the content service request of the terminal when the abnormality occurs in the media node, the embodiment of the present invention provides a processing method, a content routing function device, and a system when the content routing is abnormal. The technical solution is as follows:

 A method for processing a content routing exception, the method comprising:

 The content routing function device forwards the content service request to the media node having the requested content;

 When the deterministic response to the content service request is not received, the content routing function device reselects the media node having the requested content other than the media node;

 The content routing function device sends the content service request to the reselected media node.

 A content routing function device, the device includes:

 a forwarding module, configured to forward a content service request to a media node having the requested content;

 An exception processing module, configured to: after the forwarding module forwards the content service request, when the deterministic response to the content service request is not received, reselecting a media node having the requested content other than the media node; The content service request is sent to the reselected media node.

 The embodiment of the present invention further provides a system, where the system includes a content routing function device, configured to forward a content service request to a media node having the requested content; and when a deterministic response to the content service request is not received, Reselecting a media node having the requested content other than the media node; transmitting the content service request to the reselected media node.

 The beneficial effects of the technical solutions provided by the embodiments of the present invention are:

 When the deterministic response to the content service request is not received, the content routing function device reselects the new media node to provide content for the terminal, does not need to notify the terminal to re-route, reduces the participation process of the terminal, and improves content routing. The efficiency enables the terminal to successfully obtain the requested service by sending a content service request, thereby improving the quality of service to the terminal. DRAWINGS

 1 is a schematic structural diagram of a CDN according to an embodiment of the present invention;

 2 is a schematic structural diagram of implementing IPTV based on IMS according to an embodiment of the present invention;

 3 is a schematic structural diagram of a CDN according to an embodiment of the present invention;

4 is a schematic structural diagram of a networking provided by Embodiment 1 of the present invention; 5 is a flowchart of a processing method when a content routing exception is provided according to Embodiment 1 of the present invention;

 6 is a message interaction diagram of a method for processing a content routing exception according to Embodiment 1 of the present invention;

 7 is a message interaction diagram of a processing method when another content routing exception is provided according to Embodiment 1 of the present invention;

 8 is a message interaction diagram of a method for processing a content routing exception according to Embodiment 2 of the present invention;

 9 is a message interaction diagram of a method for processing a content routing exception according to Embodiment 3 of the present invention;

 FIG. 10 is a schematic structural diagram of a system according to Embodiment 4 of the present invention; FIG.

 FIG. 11 is a schematic structural diagram of a content routing function device according to Embodiment 4 of the present invention. detailed description

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

 The method for processing the content routing exception provided by the embodiment of the present invention includes:

 The content routing function device forwards the content service request to the media node having the requested content;

 When the deterministic response to the content service request is not received, the content routing function device reselects the media node having the requested content other than the media node, and transmits the content service request to the reselected media node.

 The CDN networking structure provided by the embodiment of the present invention, the CDN is hierarchically deployed, and the media node having the requested content is multiple. a hierarchical content network consisting of a CS (Center Server) and an ES (Edge Server), including RRS (Request Routing Server), CS and ES are content storage devices, and The user terminal delivers the content to the user terminal, and the user terminal requests the service to obtain the address (URL) of the provided content by accessing the web portal; the DNS (Domain Name System) server receives the service request of the user terminal, and then resolves based on the DNS mechanism. The content address, the RRS address is returned to the user terminal; thereafter, the user terminal sends a content request to the RRS, such as HTTP (HyperText Transfer Protocol), RTSP (Real Time Streaming Protocol), etc.; According to its stored ES load, user IP Select an ES, a user terminal and the content requests are redirected to the ES.

In order to better implement the content service request of the terminal when the media node is abnormal, referring to FIG. 2, the embodiment of the present invention provides a structure for combining the CDN and the IMS architecture to implement the IPTV service, where the MF ( Media Control Functions (media function) provides content for users, including MCF (Media Control Function) and MDF (Media Delivery Function), and MCF controls MDF for content delivery. The TPF (Transport Processing Functions) in the IMS system has a transmission function and a transmission control function;

 The SCF (Service Control Function) may select a corresponding MF providing content based on the user terminal location, the MF load, the requested content identifier, and the like;

 Alternatively, the content routing may also be performed based on the MCF, that is, the MCF selects the corresponding MF providing content according to the MCF load, the requested content identifier, etc., and the MCF is embodied as a redirecting server until the service request is routed to the related MF. Complete the content service request of the terminal.

 Referring to FIG. 3, the CDN in the embodiment of the present invention may adopt the CDN in the OPEN IPTV FORUM standard, and the CDN includes:

 CC (Cluster Controller), which is used to control the CDF (Content Delivery Function) entity for content provision;

 CDF entity for content storage and content delivery;

 CDNC (Content Delivery Network Controller), used for content routing, that is, selecting a CC functional entity for content delivery;

 The CDN in the embodiment of the present invention may also adopt other CDN structures, such as the CDN structure in FIG. 1 or in FIG.

MF structure. Example 1

 This embodiment provides a method for processing a content routing exception. The method is described by using the networking structure provided in FIG. 4 as an example. The networking structure includes:

 1) The IPTV service control function entity SCF is used to implement the IPTV service logic;

 2) User equipment (UE, User Equipment), used to initiate a SIP-based IPTV service request, that is, a content service request;

 3) The IMS core IMScore in the IMS standard, whose function complies with the functions of the IMS core in the 3GPP (3rd Generation Partnership Project) standard in the prior art;

 4) Media node (MS, Media Station), refers to a media server with media control and / or delivery capabilities. The media nodes described herein may have both media control functions and media delivery functions; or they may be separated into separate functional entities with media control functions and media delivery functions, or may have only media delivery functions.

Specifically, the media node may be the ES or CS in FIG. 1; or may be the combination of the MCF and the MDF in FIG. 2 or the MDF; or may be the combination of the CC and the CDF in the OPEN IPTV FORUM standard (FIG. 3). Or CDF; 5) a content routing function (CRF) for storing content index information, where the content index information includes content distribution information of the edge MS and the core MS, and a content service request for receiving the SIP format, according to the content index Information is routed to content service requests;

 The interface between the CRF and the MS, and the interface between the two CRFs are content routing interfaces, which have content query and content location functions. The CRF routes or forwards content service requests to the MS or other CRF through the interface.

 The CRF can also be combined with the media node function into a functional entity, ie the MS has the functionality of the CRF described herein. When the media control function and the media delivery function in the media node exist as independent entities, the CRF can also be merged with the media control function entity therein, that is, as a functional entity. For example: The MCF provided in Figure 2 may have the functionality of the CRF described herein; or the CC in the OPEN IPTV FORUM standard (Figure 3) has the functionality of the CRF described herein.

 For the CDN hierarchy, the functions of the CRF are as follows:

 The secondary CRF has the content index information of the edge MS and the secondary MS, and can perform cross-layer routing. If the routing request directly reaches the secondary CRF, the CRF can select the secondary or edge MS to provide content, when the above route fails. The CRF may forward the content service request to the upper routing entity (CRF) or the upper MS;

 There are two options for the level 1 CRF function:

 1) The first-level CRF and the second-level CRF have the same functions, and each performs cross-layer content routing. That is, if the routing request directly reaches the primary CRF, it can perform cross-layer routing, that is, the primary or secondary MS may be selected for content. Provided; when receiving the content routing request sent by the subordinate CRF, directly select the primary MS to perform the service. In this way, the primary CRF has content index information managed by the secondary CRF and content index information of the primary MS, so that it can perform cross-layer content routing.

 2) Level 1 CRF only manages the media content index information of this level, that is, as long as the content service request is received, only one level

Make a selection in the MS.

 The second option simplifies the functionality of the Level 1 CRF. It is only a subset of the Level 2 CRF function and is simple to implement; in this case, its functionality can also be combined with the Level 1 MS.

 The above-mentioned MS adopts hierarchical deployment to form a typical hierarchical or hierarchical CDN network. In Figure 4, only the two-level deployment structure is used for description. The multi-level deployment is similar, and will not be described in detail here.

 This embodiment provides a processing method when content routing is abnormal. The method provides a process when an abnormal situation occurs in the content routing process. The following abnormal conditions may occur in the content routing process:

 First: After the CRF sends the content service request to the selected MS, the MS may not respond for a long time; at this time, the CRF may reselect a new MS and resend the content service request to the newly selected MS;

Second: When the CRF sends a content service request to the selected MS, the MS may reply with a failure response. Indicates that there is no requested content. At this point, the CRF can reselect a new MS and resend the content service request to the newly selected MS.

 Referring to FIG. 5, the processing method when the content is abnormally includes:

 The UE initiates a content service request, and the content service request may be a SIP mode, such as a video on demand (VoD) request. The request may carry the content identifier requested by the user, and may also carry the user terminal type. Editing/decoding information, etc., which can be carried in the SDP (Session Description Protocol);

 102: After receiving the content service request initiated by the UE, the IMS core triggers the SCF to perform processing;

 103: After receiving the trigger of the IMS core, the SCF performs service logic processing, and sends the content service request to the CRF in the CDN network, where the media node that can provide the content requested by the user is located; wherein, the SCF may be in the IMS standard. AS (Application Server); can also be in the Open IPTV Forum IPTV standard

IPTV control (IPTV control) or TISPAN's IMS-based IPTV standard for business control functions

SCF entity, etc.

 104: After receiving the content service request, the CRF performs the MS selection, and forwards the content service request to the selected MS, and starts a CRF request timeout timer.

 When performing MS selection (ie, content routing), the CRF may locally store content index information including content of multiple edge MSs and core MSs, where the edge MS refers to the node closest to the user; the core MS refers to the edge except for the edge. MS other than MS;

 Further, when selecting MS, the CRF can be selected according to the following strategies:

 The MS selection is performed according to the content index information that is provided. In addition, when performing the selection process, the content routing function entity may also perform routing in combination with one or more of the following conditions, including: media node load, terminal location, terminal Ability, media node capabilities, etc.

If the CRF is a secondary CRF, when performing MS selection, only the MS selection is considered in the edge MS and the secondary MS. For example, when the load of the edge node closer to the terminal location exceeds 80%, the MS is considered to have reached With the load threshold, it is possible to select an edge node that is 40% or less from another load that is farther from the terminal, or a secondary MS that has a load of 10% or less. When the CRF cannot find an available MS, that is, when neither the edge MS nor the secondary MS has the requested content, the CRF may forward the content service request to the upper-level CRF processing; or, the CRF may also be to the content service. The requesting initiator (for example, the SCF) sends a redirect request, which includes the address of the upper-level CRF, and the content service request initiator obtains the address of the upper-level CRF, and then redirects the request to the upper-level CRF processing; Redirect to the upper level CRF. The routing process of the upper-level CRF for the content service request and the above CRF routing process Similarly, only the content index information it has may be different.

 105: The selected MS does not respond to the content service request; whether the network congestion causes the response to time out, or the MS downtime fails to respond, a timeout event of the CRF request timeout timer may eventually occur;

 Normally, after receiving the content service request, the MS sends a response to the CRF and provides the requested content to the terminal. When an abnormal situation occurs, the MS will not respond to the content service request, or send a message without the requested content. The MS in this embodiment does not respond;

 106: When the response of the CRF request timeout timer expires, the CRF reselects a new MS;

 The method of selecting a new MS here may be performed according to the above selection policy; that is, there may be other edge media nodes and the local media node having the requested content, so that one may be additionally selected therein; or if there are no other optional media nodes , the content routing request can be forwarded to the upper CRF for further processing. The process here gives the former case.

 107: The CRF resends the content service request to the newly selected MS.

 Referring to Figure 6, the message interaction diagram of the content routing process of Figure 5 is briefly introduced as follows:

 201: The UE initiates a content service request, and this embodiment is a SIP invite;

 202: 0^8∞6 After receiving 81? ^^^ initiated by 1^, the SCF is triggered to be processed;

 203: After receiving the trigger of the IMS core, the SCF performs service logic processing, and sends the SIP invite to the CRF in the CDN network.

 204: After receiving the SIP invite, the CRF performs the MS selection, and forwards the SIP invite to the selected MS, and starts a CRF request timeout timer.

 205: The selected MS does not respond to the SIP invite;

 206: After the response of the CRF request timeout timer expires, the CRF reselects a new MS;

 207: CRF resends SIP invite to newly selected MS

 Referring to FIG. 7, for the second abnormal situation, the content routing method includes:

 301-304 is the same as the processing of 201-204 in Fig. 6, and will not be described in detail here;

 305: When the MS that receives the SIP invite request finds that it does not have the requested content, it sends a failure response to the CRF, and this embodiment indicates the failure condition by using the SIP 4xx response;

 306: After receiving the failure response, the CRF performs the MS selection again.

The method for selecting a new MS here may be performed according to the above media node selection policy, that is, there may be other edge media nodes and the local media node having the requested content, so that one may be additionally selected therein; or if there is no other optional The media node can forward the content routing request to the upper CRF for further processing. This The flow is given as the former case.

 307: After reselection, the CRF initiates a SIP invite request to the newly selected MS.

 This embodiment provides a specific processing method for the abnormal situation in the content routing process, and the operation is simple. Meanwhile, when the CRF in this embodiment does not receive the deterministic response to the content routing request, the media node selection is performed again. The method performs re-routing, does not need to notify the terminal to re-route, reduces the participation process of the terminal, improves the efficiency of content routing, enables the terminal to successfully obtain the requested service by sending a content service request, and improves the terminal. The quality of service prevents the content service request of the terminal from failing. The processing mechanism can be well combined with the IMS signaling routing mechanism, and the IMS and the CDN can be seamlessly combined.

 The method provided in this embodiment is described for a secondary CDN network. Obviously, this method is also applicable to a multi-level CDN network, and details are not described herein again.

 The foregoing method is described by taking the networking structure provided in FIG. 4 as an example. However, the method provided by the embodiment of the present invention is not limited to the networking structure and is applicable to any networking structure, and is not described in detail herein. Example 2

 This embodiment provides a method for processing a content routing exception. For the Open IPTV Forum IPTV standard, an embodiment of the method of the present invention and a combination of the prior art may be further provided. This embodiment only gives a description of the case where the content node does not respond or the response timeout. Referring to Figure 8, the processing method of the content path exception is briefly described as follows:

The processes of 401-407 are basically the same as those of 201-207 described above, except that the SCF in this embodiment is replaced by IPTV control, the CRF function is implemented by the CDNC function, and the CC and CDF constitute a media node.

 When the media node selected by the CDNC according to the content service request does not respond or the response times out, the CDNC reselects a media node, here select CC; thereafter the CDNC sends a content service request to the new media node.

 For the case where the media node responds to no content, here is the case where the CC response has no content, and the corresponding flow can also be given according to the description.

 In addition, the CRF function here can also be combined with the CC function, and does not affect the existing CDNC function; then the CDF is the media node, and it is easy to give the relevant processing flow, which will not be described in detail here. Example 3

This embodiment provides a processing method when content routing is abnormal. For the TISPAN IPTV standard, an embodiment combining the method of the present invention and the prior art may be further provided. This embodiment gives an explanation only for the case where the content node does not respond or the response times out. Referring to Figure 9, the processing method when the content routing is abnormal is briefly described as follows: 501-507 is basically the same as the above 201-207, except that the CRF function in this embodiment is implemented by the MCF function, and the MDF is used as a media node.

 When the MCF selected by the MCF according to the content service request does not respond or the response times out, the MCF reselects a media node, here selects the MDF; thereafter the MCF sends a content service request to the new media node MDF. A detailed processing flow can be easily given by Embodiment 1, and will not be described again here.

 For the case where the media node responds to no content, here is the case where the MDF responds to no content, and it is also possible to easily give the corresponding flow according to the description.

 In addition, CRF can also exist as an independent functional entity, and MCF and MDF form a media node. The SCF forwards the content service request to the CRF, which further selects the media node and sends a content service request thereto; when the MCF response times out or responds to no content, the CRF can reselect a media node and send a content service request thereto. Example 4

 Referring to FIG. 10, this embodiment provides a system, including: a content routing function device 41, configured to forward a content service request to a media node 42 having the requested content; and when the content service request is not received. In response to the sexual response, the media node 42 having the requested content other than the media node 42 is reselected; the content service request is sent to the reselected media node 42.

 The system can also include:

 The terminal device 43 is configured to initiate the foregoing content service request;

 The multimedia subsystem core device 44 is configured to forward the content service request sent by the terminal device 43 and trigger the service control function device 45 to perform service processing;

 The service control function device 45 is configured to: after receiving the service request triggered by the multimedia subsystem core device 44, perform service logic processing, and send the content service request to the selected content routing function device 41 through the multimedia subsystem core device 44, The content routing function device 41 selects the media node 42 and sends a content service request to the selected media node 42;

 The media node 42 is configured to check whether the content of the content service request exists after receiving the content service request of the content routing function device 41, and if yes, send an acknowledgment response to the content routing function device 41, and provide the requested content to the terminal. If not, the content routing function device 41 is sent a message without the requested content or does not respond to the content service request.

 The deterministic response that the content routing function device 41 does not receive the content service request includes:

The content routing function device 41 receives a message that the media node 42 does not have the requested content, or the content routing function The device 41 does not respond to the media node 42 within the preset time.

 The media node 42 described herein may have both a media control function and a media delivery function; or it may be separated into separate functional entities having media control functions and media delivery functions, or may have only media delivery functions.

 Specifically, the media node 42 may be the ES or CS in FIG. 1; or may be the combination of the MCF and the MDF in FIG. 2 or the MDF; or may be the CC and CDF in the OPEN IPTV FORUM standard (FIG. 3). Combination or CDF; When the media control function and the media delivery function in the media node 42 exist as independent entities, the content routing function device 41 can also be merged with the media control function entity therein, that is, as a functional entity. For example: The MCF in Figure 2 may have the functionality of the content routing function device 41 described herein; or the CC in the OPEN IPTV FORUM standard (Figure 3) has the functionality of the content routing function device 41 described herein.

 The content routing function device 41 may store the content index information of the plurality of media nodes 42 and the core media nodes in advance, and the content of the content index information is the same as that in the first embodiment, and may be implemented when the media node 42 is selected. The strategy described in Example 1 is selected and will not be described in detail herein.

 Referring to Figure 11, the content routing function device includes:

 The forwarding module 411 is configured to forward the content service request to the media node having the requested content;

 The exception processing module 412 is configured to: after the forwarding module 411 forwards the content service request, when not receiving the deterministic response to the content service request, reselecting the media node having the requested content other than the media node; sending the content service request to Reselected media node.

 Further, the forwarding module 411 includes:

 a media node selection unit, configured to select, according to content index information of the content of the plurality of edge media nodes and the core media node that are included in the content, the media node having the content requested in the content service request;

 And a forwarding unit, configured to forward the content service request to the media node selected by the media node selection unit.

 The exception handling module 412 includes:

 An abnormal situation determining unit, configured to: when receiving a message that the media node selected by the forwarding module does not have the requested content, or when the media node selected by the forwarding module does not respond within a preset time, determining that an abnormal situation occurs;

 And an exception processing unit, configured to: when the abnormal condition determining unit determines that an abnormal situation occurs, reselect a media node having the requested content other than the media node; and send the content service request to the reselected media node.

In this embodiment, the media node is selected according to the content service request, and the content routing is implemented, and the operation is simple and easy to implement. Meanwhile, the content index information of the plurality of edge media nodes and the core media node stored locally may only have the requested content. The media node is selected. At the same time, when the deterministic response to the content routing request is not received, the method of re-selecting the media node is used to perform re-routing, without notifying the terminal to re-route, minus The participation process of the terminal is reduced, the efficiency of content routing is improved, and the terminal can successfully obtain the requested service by sending a content service request, thereby improving the quality of service to the terminal, and the processing mechanism can be good and IMS signaling. The combination of routing mechanisms allows seamless integration of IMS and CDN. All or part of the technical solutions provided by the above embodiments may be implemented by software programming, and the software program is stored in a readable storage medium such as a hard disk, an optical disk or a floppy disk in a computer. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., which are within the spirit and scope of the present invention, should be included in the protection of the present invention. Within the scope.

Claims

Claim  A method for processing a content routing exception, the method comprising:  The content routing function device forwards the content service request to the media node having the requested content;  When the deterministic response to the content service request is not received, the content routing function device reselects the media node having the requested content other than the media node;  The content routing function device sends the content service request to the reselected media node. The method for processing a content routing exception according to claim 1, wherein the content routing function device forwarding the content service request to the media node having the requested content comprises:  The content routing function device selects the media node having the requested content based on the content index information of the content of the plurality of edge media nodes and the core media nodes that are included by itself, and forwards the content service request to the selected media node. The method for processing a content routing exception according to claim 1, wherein when the edge media node and the local media node have no requested content, the method further includes:  The content routing function device forwards the content service request to the upper-level content routing function device. The method of processing a content routing exception according to claim 1, wherein the content service request is a request of a session initiation protocol mode. 5. The method of processing a content routing exception according to claim 1, wherein the determining that the deterministic response to the content service request is not received comprises:  The content routing function device receives a message that the media node does not have the requested content, or the content routing function device does not respond to the media node within a preset time. A content routing function device, wherein the device comprises:  a forwarding module, configured to forward a content service request to a media node having the requested content; An exception processing module, configured to: after the forwarding module forwards the content service request, when the deterministic response to the content service request is not received, reselecting a media node having the requested content other than the media node; The content service request is sent to the reselected media node. The content routing function device according to claim 6, wherein the forwarding module comprises: a media node selection unit, configured to content according to content of a plurality of edge media nodes and core media nodes included in the media node Index information, selecting a media node having content requested in the content service request;  And a forwarding unit, configured to forward the content service request to the media node selected by the media node selection unit. The content routing function device according to claim 6, wherein the exception processing module comprises: an abnormality determining unit, configured to: when receiving a message that the media node selected by the forwarding module does not have the requested content, Or determining that an abnormal situation occurs when the media node selected by the forwarding module does not respond within a preset time;  And an exception processing unit, configured to: when the abnormality determining unit determines that an abnormal situation occurs, reselect a media node having the requested content other than the media node; and send the content service request to the reselected media node. 9. A system, wherein the system comprises:  a content routing function device, configured to forward the content service request to the media node having the requested content; and when the deterministic response to the content service request is not received, reselect the media node having the requested content other than the media node Sending the content service request to the reselected media node. 10. The system according to claim 9, wherein the system further comprises: a terminal device, a multimedia subsystem core device, a service control function device, and a media node;  The terminal device is configured to initiate the content service request;  The multimedia subsystem core device is configured to forward the content service request sent by the terminal device, and trigger the service control function device to perform service processing;  After receiving the service request triggered by the core device of the multimedia subsystem, the service control function device performs service logic processing, and sends a content service request to the selected content routing function device by using the multimedia subsystem core device; After receiving the content service request of the content routing function device, the media node checks whether it has the content of the content service request, and if yes, sends an acknowledgement response to the content routing function device, and is The terminal provides the requested content; if not, sends a message to the content routing function device that does not have the requested content or does not respond to the content service request. 11. The system of claim 9, wherein the content routing function device does not receive a deterministic response to the content service request comprises:  The content routing function device receives a message that the media node does not have the requested content, or the content routing function device does not respond to the media node within a preset time.