WO2013123860A1

WO2013123860A1 - Method and system for achieving content distribution network interconnection routing

Info

Publication number: WO2013123860A1
Application number: PCT/CN2013/071481
Authority: WO
Inventors: 金伟毅
Original assignee: 中兴通讯股份有限公司
Priority date: 2012-02-23
Filing date: 2013-02-06
Publication date: 2013-08-29
Also published as: CN103297337A

Abstract

Provided are a method and system for achieving CDN interconnection routing. The method comprises: a CDN server judging the types of received content request messages; and according to the different types of the content request messages, forwarding the content request messages. Proposed is a novel forwarding routing manner under the condition of CDN interconnection. By judging the types of received content request messages, the content request messages can be forwarded in different manners. The routing of a complex CDN interconnection network can be supported, the problem of routing loops under the condition of complex CDN interconnection can be prevented, and the content request messages can be forwarded many times through a middle CDN network to achieve routing even if a contract is not directly signed between an upstream CDN server and a downstream CDN server, so as to achieve the purpose of optimizing a network.

Description

Method and system for realizing content distribution network interconnection routing

The present invention relates to the field of network communication technologies, and in particular, to implementing a content distribution network

(CDN, Content Delivery Network) Method and device for interconnecting routes. Background technique

Content-based services have gradually become the mainstream of traffic in the Internet in recent years. Content-based services include HTTP browsing, video and file downloads, P2P downloads, and more. These services have the characteristics of large download traffic and high content repeatability.

In order to reduce the impact of content-based services on the Internet and to increase user download speeds, operators and third-party independent providers have begun to widely use CDNs to distribute content. The CDN can distribute the content to the network edge node in advance, and redirect the user's request to the CDN node when the user requests the content. In this way, the download speed of the user can be greatly accelerated, and at the same time, the user request for the same area can also prevent the same content from being transmitted multiple times on the WAN.

With the widespread use of CDNs, the island-based CDNs provided by operators and third-party providers are no longer able to meet the growing demand of the network. An islanded CDN is a distribution that only provides content for a regional network, or simply contracts with certain content service providers (CSPs) to provide distribution acceleration for certain content. Therefore, there is an urgent need to establish a set of interconnection and interoperability systems between CDNs, so that CDNs can share distribution and content resources, and provide distribution acceleration for the entire Internet and most content. The CDNi Working Group has been established in the Internet Engineering Task Force (IETF) to focus on the interconnection between CDNs.

Figure 1 shows the interworking architecture between current CDNs. The CDN user 101 is an end user node that receives the content distribution service of the CDN. There are three roles in the CDN network, CSP 102 is responsible for providing content, and the upstream CDN 103 contracts with the content service provider to perform distribution of related content, and the first content request of the user is also sent to the upstream CDN 103 through the user request interface. When the upstream CDN 103 considers that the content requested by the user is suitable for distribution by the downstream CDN 104, the upstream CDN 103 can forward the user's request to the downstream CDN 104 for processing. Finally, the CDN user 101 can download the relevant content through the downstream CDN 104. The upstream CDN 103 and the downstream CDN 104 are interconnected by a CDM interface, and the downstream CDN 104 can acquire content from the upstream CDN 103 through a content acquisition interface.

In the scenario of CDN interconnection, the first problem to be solved is the cyclic routing problem in the content request forwarding process. For example, after the user requests to be sent to the upstream CDN 103, the upstream CDN 103 forwards the request to the downstream CDN 104. If the downstream CDN has not yet obtained the relevant content, the downstream CDN needs to download the corresponding content through the upstream CDN 103 before the content can be sent to the CDN user 101. However, if the upstream CDN 103 mistakenly considers the content acquisition request of the downstream CDN 104 to be a request from the user, it forwards it to the downstream CDN 104. At this point, the request will continue to forward between the upstream CDN 103 and the downstream CDN 104, causing an infinite loop of routing.

In order to solve such an infinite loop of routing, the CDM working group adopts the following solution: The upstream CDN 103 and the downstream CDN 104 sign a contract, and it is agreed that when the downstream CDN 104 requests content from the upstream CDN 103, it is necessary to adopt a special agreement. A resource locator (URL, Uniform/Universal Resource Locator) is requested to distinguish it from a normal user's request. The specific process is shown in Figure 2:

201) The CDN user node requests the relevant content using the CSP's URL, and the user request will be sent to the upstream CDN contracted with the CSP.

202) The upstream CDN analyzes the user information and the requested content, and selects a suitable downstream CDN for the current business processing.

203) The upstream CDN redirects the CDN user node to the downstream CDN. At this point, the upstream CDN can use HTTP redirects or DNS redirects to direct users to a new one. 204) The CDN user node resends the user request to the downstream CDN according to the new URL.

205) The downstream CDN finds that the content is currently not cached on the node of the CDN, and needs to obtain content from the content source to provide services for the user.

206) The downstream CDN sends a content acquisition request using a special address (upstream CDN URL) agreed with the upstream CDN.

207) The upstream CDN determines, by the URL of the content acquisition request, that it is a content acquisition request sent by the downstream CDN. At this point, the upstream CDN no longer forwards the request, but processes it by itself.

208) The upstream CDN sends the content to the downstream CDN.

209) The downstream CDN sends the content to the CDN user node.

The above process can solve the cyclic routing problem of forwarding between CDNs. However, the solution is limited to situations where there is only one upstream CDN forwarding the request to a downstream CDN. If there are multiple levels of forwarding, or if a mesh structure is established between multiple CDNs, the solution does not solve the round-robin routing problem of forwarding. Summary of the invention

In view of this, the main purpose of the embodiments of the present invention is to provide a method and system for implementing CDN interconnection routing, which can prevent the cyclic routing problem in the case of complex CDN interconnection.

To achieve the above objective, the technical solution of the embodiment of the present invention is implemented as follows:

A method for implementing a content distribution network (CDN) interconnection route, the method comprising: determining, by a CDN server, a type of a received content request message;

The content request message is forwarded according to different types of the content request message. The CDN server determines, according to the type of the received content request message, that the CDN server performs type determination according to one of a protocol type, a source address, a destination address, a message header, or a message content of the content request message.

The requesting message for the content according to different types of the content request message Forward to:

When the type of the content request message is a user request message, determining a forwarding path according to the pre-stored user request forwarding routing table, and forwarding the content request message;

When the type of the content request message is a content acquisition request message, the forwarding path is determined according to the pre-stored content acquisition request forwarding routing table, and the content request message is forwarded.

Further, the method further includes:

The user request forwarding routing table and the content obtaining request forwarding routing table determined by statically configuring or dynamically acquiring the subscription information are stored in the CDN server; wherein the user request forwarding routing table uses the user address information as an index. The content acquisition request forwarding routing table is indexed by the content identifier.

The content request message is forwarded according to different types of the content request message to:

When the type of the content request message is a user request message, determining a forwarding path according to a pre-stored user request forwarding routing algorithm, and forwarding the user request message;

And when the content request message is a content acquisition request message, determining a forwarding path according to the pre-stored content acquisition request forwarding routing algorithm, and forwarding the content acquisition request message.

When the type of the content request message is a user request message or a content acquisition request message, determining a forwarding path by using a Border Gateway Protocol (BGP) message, an application layer traffic optimization (ALTO) server, or a CDNi interface, and performing the content request message Forward.

The content request message is forwarded to:

The CDN server keeps the type of the content request message unchanged, and forwards the message through the content type, source address, destination address, message header or message of the content request message. A type of content that identifies the content request message.

A system for implementing a CDN interconnection route, the system comprising: a CDN server, configured to determine a type of a received content request message; and forwarding the content request message according to different types of the content request message .

The CDN server is specifically configured to perform type determination according to one of a protocol type, a source address, a destination address, a message header, or a message content of the content request message.

The CDN server is specifically configured to: when the type of the content request message is a user request message, determine a forwarding path according to the pre-stored user request forwarding routing table, and forward the content request message; When the type of the content request message is a content acquisition request message, the forwarding path is determined according to the pre-stored content acquisition request forwarding routing table, and the content request message is forwarded.

Further, the CDN server is further configured to store a user request forwarding routing table and a content obtaining request forwarding routing table determined by statically configuring or dynamically acquiring subscription information; wherein, the user requests the forwarding routing table to The user address information is an index, and the content acquisition request forwarding routing table is indexed by the content identifier.

The CDN server is specifically configured to: when the type of the content request message is a user request message, determine a forwarding path according to a pre-stored user request forwarding routing algorithm, and forward the user request message; When the type of the content request message is a content acquisition request message, the forwarding path is determined according to the pre-stored content acquisition request forwarding routing algorithm, and the content acquisition request message is forwarded.

The CDN server is specifically configured to: when the type of the content request message is a user request message or a content acquisition request message, determine a forwarding path by using a BGP message, an ALTO server, or a CDM interface, before performing the content request message. turn.

The CDN server is specifically configured to keep forwarding the type of the content request message, where the protocol type, source address, and destination of the content request message are A type of address, header, or message content that identifies the type of content request message.

The embodiment of the present invention provides a forward routing method in the case of a new CDN interconnection. By determining the type of the received content request message, the content request message is forwarded in different manners, which can support complex CDN interconnection. The routing of the network can prevent the cyclic routing problem in the case of complex CDN interconnection, and even if the upstream CDN server and the downstream CDN server do not directly sign the contract, the content request message can be performed multiple times through the intermediate CDN network. To achieve routing, to achieve the purpose of optimizing the network. DRAWINGS

FIG. 1 is a schematic structural diagram of interworking between existing CDNs;

2 is a schematic flow chart of existing CDNi redirection;

3 is a schematic flowchart of an implementation of a method for implementing a CDN interconnection route according to an embodiment of the present invention; FIG. 4 is a schematic flowchart of an implementation manner of a method for implementing a CDN interconnection route according to an embodiment of the present invention;

5 is a schematic structural diagram of a forward routing table of a user request message according to an embodiment of the present invention; and FIG. 6 is a schematic flowchart of a forward routing table of a content obtaining request message according to an embodiment of the present invention. detailed description

In view of the above problems, the embodiments of the present invention propose to divide the CDN forwarding processing into two categories: user request forwarding and content acquisition request forwarding. The user request forwarding and content acquisition request forwarding are forwarded in different ways, and the type of the content request message can also be retained when forwarding. This will prevent loop routing problems even in the case of complex CDN interconnections.

The basic idea of the embodiment of the present invention is: The CDN server determines the type of the received content request message; and forwards the content request message according to different types of the content request message. FIG. 3 is a flowchart showing an implementation of a method for implementing a CDN interconnection route according to an embodiment of the present invention. As shown in FIG. 3, the method includes the following steps:

Step 301: The CDN server determines the type of the received content request message. In the embodiment of the present invention, the type of the content request message specifically includes a user request message and a content acquisition request message. The user request message refers to a content request initiated by the user, including an initial content request initiated by the CDN user node and a user request message forwarded by the CDN server; the purpose of the user request message is to download the content to the device of the end user. The content acquisition request message refers to a content request initiated by another CDN server or a CDN storage node, including an initial content acquisition request initiated by another CDN and a content acquisition request message forwarded by the CDN server; the purpose of the content acquisition request message is The content is distributed internally by the CDN, that is, the storage node of the downstream CDN obtains content for caching.

The CDN server determines the type of the received content request message as: analyzing the received content request message to determine the type of the content request message; specifically, the protocol that the CDN server can request the message according to the received content. The type can be differentiated by the data plane bearer protocol and the control plane request message protocol. For example, the user request message can be implemented by using an HTTP request; the content acquisition request message can be implemented by using an FTP request; or

The CDN server can also distinguish by the source address of the received content request message; for example, the CDN server can pre-store the IP address or IP address segment of other CDN storage nodes, so that the request sent by the node in the address range can be considered Is a content acquisition request message; or,

The CDN server may also distinguish by the destination address of the received content request message; the destination address may include a destination IP address, a destination URL, or a destination port number of the content request message, etc.; for example, the CDN may request a message and content for the user. Get the request message to assign a different URL address, for different types of content request messages require different URLs to visit ask. For example, ask users to use cdna.com when they access, and other CDNs to use cdnget.cdna.com; or,

The CDN server can also distinguish the message header or the message content of the received content request message; for example, the content acquisition request message can be implemented by adding a special parameter or _TAG to the message header or the message content.

Step 302: The CDN server forwards the content request message according to different types of the content request message.

Here, the CDN server selects a different routing manner to perform forwarding according to the determined different types of the content request message. Specifically, when the type of the content request message is a user request message, the CDN server may specifically pre-store by querying. Routing table, performing local pre-stored routing algorithm or querying other CDN servers, etc. for routing mode selection; specific methods include but are not limited to:

The CDN server performs the routing mode selection by statically configuring the user request forwarding rule or the forwarding routing table. The user request forwarding routing table uses the user address information as an index.

The CDN server obtains the service-scope hot-selling information of the other CDN server through the Border Gateway Protocol (BGP) message, and establishes a local routing table. After receiving the user request message, the CDN server corresponds to the local routing table according to the user IP address information. The service scope or subscription information of other CDN servers, select the appropriate CDN server for forwarding;

The CDN server queries the application layer traffic optimization (ALTO, Server-Layer Traffic Optimization) server, queries the network topology structure through the address information of the user request message, and selects a suitable CDN server to forward;

The CDN server obtains information about the service capabilities, load status, and cost status of other CDN servers through the CDM interface or other interfaces, and selects a suitable CDN server to forward according to the information;

The CDN server obtains storage in other CDN servers through the CDM interface or other interfaces. In the case of content, select a suitable CDN server to forward according to the content of the cached content in the CDN server;

The CDN server queries other CDN servers through the CDM interface or other interfaces to obtain a suitable CDN for forwarding.

The above selection methods can be combined with each other to jointly weigh forward selection of the CDN server that implements the user request message. Among them, the basic selection principle is to select a CDN server that is close to the user and is in good condition to provide services for users. That is, the main factor in selection is based on the user's address (geographic location) information. For the result of the selection, the user can be transferred to another CDN server through HTTP/DNS forwarding, or it can be selected for processing.

When the type of the content request message is a content acquisition request message, the CDN server may specifically perform a routing mode selection by querying a local pre-stored routing table, performing a local pre-stored routing algorithm, or querying other CDN servers, etc. But not limited to:

The CDN server determines the content acquisition request forwarding routing table by statically configuring the content subscription relationship and the upstream CDN server node information of the content, and determines how to forward the content acquisition request message; wherein the content acquisition request forwarding routing table is content Identifies as an index;

The CDN server obtains the contract relationship of other CDN servers through the CDNi interface or a routing protocol such as BGP, and determines the information of the upstream CDN server for different contents;

The CDN server obtains the content of the cached content in the other CDN server through the CDNi interface or other protocols, and determines the forwarding rule of the content acquisition request;

The above selection methods can be combined with each other to jointly weigh the CDN server selection in the content acquisition request message. The basic selection principle is to select a CDN server that is close to the content acquisition request message and that is currently in good condition to provide services for the user. That is, the main factor in selection is based on the information of the content, and the CDN server that owns the content or is close to the final content owner (CSP). For the result of the selection, the content acquisition request may be transferred to another CDN server through HTTP/DNS forwarding, or it may be selected for processing. Specifically, after determining the route forwarding manner of the content request message, the CDN server may notify the CDN user node or the downstream CDN cache node to switch to the new CDN server. At this time, the CDN server should keep the type of the content request message unchanged, that is, for the user request message, it should be ensured that the new CDN server can still recognize that the content request message is a user request message after forwarding; for the content acquisition request message, After the forwarding is guaranteed, the new CDN server can still recognize that the content request message is a content acquisition request message. Here, the CDN server may identify the type of the content request message by the protocol type of the content request message, the message source address, the message destination address, the message header or the message content, and the like.

It should be understood that maintaining the type of the content request message unchanged does not mean that the manner used to identify the content request message is unchanged. For example, when the CDN B forwards the content request message of the CDN C to the CDN A, the CDN B can determine the identification manner of the content request message according to a specific subscription manner. The CDN B can send the destination address of the content request message, such as cdnbget.csp.com, through the CDN C to determine that the content request message sent by the CDN C is a content acquisition request message. However, CDN B can instruct CDN C to use a special port number when sending a content request message to the CDNA when forwarding the CDN C. The CDNA can determine, according to the special port number, that the content request message sent by the CDN C is a content acquisition request message. As such, in the embodiment of the present invention, when the CDN server can make the CDN server of the next hop recognize the content request message type, and the identified type is consistent with the type recognized by the CDN server, it can be considered as the content request message type. a way of keeping.

FIG. 4 is a flowchart showing an implementation of a method for implementing a CDN interconnection route according to an embodiment of the present invention. As shown in FIG. 4, the embodiment includes the following steps:

401) The CDN user node sends a content request message, and the content request message is processed by the upstream CDNA because the CSP is contracted with the upstream CDNA.

402) The upstream CDN A uses the foregoing method to distinguish that the content request message is of a type that is a user request message sent by the user. The upstream CDNA performs a user request forwarding algorithm to determine This request should be executed by CDN B. At this time, the upstream CDN A notifies the CDN user node to forward, and the specific forwarding method may be DNS or HTTP forwarding. In the forward forwarding, the upstream CDN A can identify that the forwarding is a user request forwarding by means of a specific address encoding or the like.

403) The CDN user node resends the content request message to CDN B as indicated by the upstream CDNA. The CDN user node does not necessarily need to analyze the upstream CDN A in the address code to identify that this forwarding is the user request forwarding.

404) The CDN B analyzes the received content request message, and identifies that the type of the content request message is a user request message. CDN B performs a user request forwarding algorithm to determine that this request should be performed by the downstream CDN C. At this time, the CDN B notifies the CDN user node to forward, and maintains the identity of the current content request message.

405) The CDN user node resends the content request message to the downstream CDN C as instructed by CDN B.

406) The downstream CDN C analyzes the received content request message, determines that the type of the content request message is a user request message, and the CDN C performs a user request forwarding algorithm to determine that the request should be handled by itself. Since CDN C does not currently store this content, CDN C needs to obtain content from other CDN servers. The CDN C executes a content acquisition request forwarding algorithm, and determines that a content acquisition request should be sent to the CDN B. The CDN C sends a content acquisition request to the CDN B.

407) The CDN B receives the content request message of the CDN C, and determines that the type of the content request message is a content acquisition request message sent by the downstream CDN, for example, by the content request message being a special URL sent to the CDN for type determination. CDN B itself does not have corresponding content, and CDN B executes a content acquisition forwarding algorithm, and judges that the content acquisition request message should be forwarded to CDN A. The CDN B forwards the content acquisition request of the CDN C and maintains the identity of the content acquisition request message unchanged.

408) CDN C sends a content acquisition request message to the upstream CDN as directed by CDN B

A. 409) The upstream CDNA receives the request of the CDN C, and first determines that the type of the content request message is a content acquisition request message. Since the upstream CDN A itself has this content, the upstream CDN A returns the content response directly to CDN C.

410) After the CDN C obtains the content from the upstream CDN A, it returns the content response to the end user.

FIG. 5 is a schematic flowchart showing the configuration of a forwarding routing table of a user request message according to an embodiment of the present invention, and determining how to forward a route. As shown in FIG. 5, the construction process includes the following steps:

501) After the upstream CDN and the downstream CDN reach a contractual relationship, the downstream CDN reports the IP address/geographic range covered by the upstream CDN and its capability and load to the upstream CDN through the BGP protocol, the RRI interface or the Control interface of the CDNi.

Here, the reporting may be sent periodically, or may be triggered by an upstream CDN request or other event (such as a downstream CDN overload).

502) After receiving the information of the downstream CDN, the upstream CDN organizes the related information and constructs a user request forwarding routing table.

For example, according to the range covered by the downstream CDN, the forward destination address of the corresponding IP address entry is set to the address of the downstream CDN, and the like. Upon receiving the user request message, the upstream CDN may forward the user request message to the destination downstream CDN address of the corresponding entry in the forwarding request routing table according to the source IP address of the user request message.

FIG. 6 is a flowchart showing the construction flow of a forward routing table of a content acquisition request message according to an embodiment of the present invention, by using a table, or using other algorithms to determine how to forward a route. As shown in FIG. 6, the construction process includes the following steps:

601) After the upstream CDN and the downstream CDN reach a contractual relationship, the upstream CDN sends the CSP information signed by itself to the downstream CDN. Here, the upstream CDN can also forward the CSP subscription information of other upstream CDNs that it can indirectly connect to the downstream CDN. For example, the upstream CDN can inform the downstream CDN that it has signed up directly with Sina, and can also inform that it can be forwarded twice to the CDN node contracted with Sohu.

602) After receiving the CSP subscription information of the upstream CDN, the downstream CDN updates the content of the corresponding content to the forwarding routing table entry.

The method of updating may be based on whether the upstream CDN is close to the CSP. For example, for Sina, if the downstream CDN does not have a forward transfer to reach the CDN contracted with Sina, the downstream CDN can directly point the Sina related items to the upstream CDN (since the upstream CDN and Sina directly sign). When the content acquisition request message of the other CDN is subsequently received, the downstream CDN can determine how to forward the content acquisition request message by using the forward routing table information of the corresponding content.

The embodiment of the invention further discloses the system for implementing the CDN interconnection routing method, the system comprising: a CDN server, configured to determine a type of the received content request message; according to different types of the content request message, The content request message is forwarded.

Further, the CDN server is further configured to store a user request forwarding routing table and a content obtaining request forwarding routing table determined by statically configuring or dynamically acquiring subscription information, where the user requests the forwarding routing table to The user address information is an index, and the content acquisition request forwarding routing table is indexed by the content identifier. The CDN server is specifically configured to: when the type of the content request message is a user request message, determine a forwarding path according to a pre-stored user request forwarding routing algorithm, and forward the user request message; When the type of the content request message is a content acquisition request message, the forwarding path is determined according to the pre-stored content acquisition request forwarding routing algorithm, and the content acquisition request message is forwarded.

The CDN server is specifically configured to: when the type of the content request message is a user request message or a content acquisition request message, determine a forwarding path by using a BGP message, an ALTO server, or a CDNi interface, before performing the content request message. turn.

The CDN server is specifically configured to maintain the type of the content request message and perform forwarding, where the content of the content request message is a protocol type, a source address, a destination address, a message header, or a message content. To identify the type of the content request message.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Industrial applicability

In the embodiment of the present invention, by referring to the type of the received content request message, the content request message is forwarded in different manners, which can support the routing of the complex CDN internetwork, thereby preventing the problem of cyclic routing in the case of complex CDN interconnection. .

Claims

Claim

A method for implementing a CDN interconnection route in a content distribution network, the method comprising:

The CDN server determines the type of the received content request message;

The content request message is forwarded according to different types of the content request message.

2. The method according to claim 1, wherein the CDN server determines the type of the received content request message as:

The CDN server performs type determination according to one of a protocol type, a source address, a destination address, a message header, or a message content of the content request message.

The method according to claim 1, wherein the content request message is forwarded according to different types of the content request message:

The method according to claim 3, wherein the method further comprises: storing the user request forwarding routing table and the content obtaining request forwarding routing table determined by statically configuring or dynamically acquiring the subscription information. In the CDN server, the user request forwarding routing table takes the user address information as an index, and the content obtaining request forwarding routing table uses the content identifier as an index.

When the type of the content request message is a content acquisition request message, determining a forwarding path according to the pre-stored content acquisition request forwarding routing algorithm, and performing the content acquisition request message Forward.

When the type of the content request message is a user request message or a content acquisition request message, the forwarding path is determined by using a border gateway protocol BGP message, an application layer traffic optimization ALTO server or a CDM interface, and the content request message is forwarded.

The method according to any one of claims 1 to 6, wherein the content request message is forwarded to:

The CDN server keeps the type of the content request message unchanged, and forwards the content request message by using one of a protocol type, a source address, a destination address, a message header, or a message content of the content request message. type.

A system for implementing CDN interconnection routing, the system comprising: a CDN server, configured to determine a type of a received content request message; according to different types of the content request message, The content request message is forwarded.

The system according to claim 8, wherein the CDN server is specifically configured to perform type determination according to a protocol type, a source address, a destination address, a message header, or a message content of the content request message. .

The system according to claim 8, wherein the CDN server is specifically configured to: when the type of the content request message is a user request message, determine a forwarding path according to a pre-stored user request forwarding routing table. And forwarding the content request message; when the type of the content request message is a content acquisition request message, determining a forwarding path according to the pre-stored content acquisition request forwarding routing table, and forwarding the content request message .

The system according to claim 10, wherein the CDN server is further configured to store a user request forwarding routing table and a content acquisition request forwarding routing table determined by static configuration or dynamic acquisition of subscription information. Wherein the user requests a forwarding routing table to The user address information is an index, and the content acquisition request forwarding routing table is indexed by the content identifier.

The system according to claim 8, wherein the CDN server is specifically configured to: when the type of the content request message is a user request message, determine a forwarding path according to a pre-stored user request forwarding routing algorithm. And forwarding the user request message; when the type of the content request message is a content acquisition request message, determining a forwarding path according to the pre-stored content acquisition request forwarding routing algorithm, before performing the content acquisition request message turn.

The system according to claim 8, wherein the CDN server is specifically configured to pass the BGP message, the ALTO server or the CDM when the type of the content request message is a user request message or a content acquisition request message. The interface determines a forwarding path, and forwards the content request message.

The system according to any one of claims 8 to 13, wherein the CDN server is specifically configured to keep the type of the content request message unchanged, and forward the content through the content request message. A type of protocol type, source address, destination address, header, or message content that identifies the type of content request message.