WO2007039576A1

WO2007039576A1 - A content distribution system and a user request redirection method thereof

Info

Publication number: WO2007039576A1
Application number: PCT/EP2006/066916
Authority: WO
Inventors: Na Li
Original assignee: Nokia Siemens Networks Gmbh & Co. Kg
Priority date: 2005-09-30
Filing date: 2006-09-29
Publication date: 2007-04-12
Also published as: CN1941736A

Abstract

This invention discloses a content distribution system. A tree shape structure whose root node is a server is created, the leaf node servers of said tree shape structure are edge nodes, the non-leaf node of said tree shape structure stores content and distributes the content to its son node servers. This invention also proposes a user request redirection method using said content distribution system. The method comprises the following steps: firstly, the end user sends a content request to the leaf node server to which said end user belongs; secondly, if said leaf node has stored the content requested by the end user, said content is downloaded to said end user; otherwise, said end user sends a content request to the brother node of said leaf node; and next, repeating the above step until the requested content is downloaded to said end user or the last node server has been visited. By adopting this method, the end user sends a content request first to the edge node, and the edge node can provide the great majority of the content requested by the end users, and hence avoids the need to send a request to the upper nodes and the bandwidth of the IP network is thus saved.

Description

A content distribution system and a user request redirection method thereof

Field of the Invention

The present invention relates to a content distribution system and a user request redirection method based on the same, particularly to a system which is used for content distribution on the internet and a user request redirection method using said system.

Background of the Invention

Different from the Public Switched Telephone Network (PSTN) which mainly provides mutual end-to-end symmetrical telephone service, an IP network mainly provides asymmetrical data service from servers to clients. It is a basic method of information service on an IP network that a user sends a request to a server storing various information for desired information, and the desired information is then sent to said user by the server according to the user's request. The most popular Web service on IP networks is a service based on server/client and the service model of which is shown in Figure 1.

As can be seen from Figure 1, in the case that different information content is stored on each website, users located anywhere in the world can access the content in the same server because the IP network is accessed without geography and distance limitation. Thus, it can lead to the bottleneck of the processing speed of a server itself; on the other hand, it can lead to the congestion of the backbone network service capacity .

In order to solve the aforementioned problems of speed and congestion, Content Distribution Network (CDN, sometimes referred to as Content Distributing Network or Content Delivery Network) occurs. Content Distribution Network is a type of advanced streaming distribution network established on the present Internet. Said Content Distribution Network distributes Cache servers to the relatively centralized regions or networks that are accessed by users, stores the content on the website's origin server in Cache servers located at different regions then. Through the Dynamic Streaming Distribution Controller and by means of the Global Server Load Balance (GSLB) , the user' s request is directed to the Cache server which is closest to user and works normally and responds to the user's request, so that the speed of response to the request and the availability of service, and hence the quality of service of the Internet is improved.

The structure of a CDN network, as shown in Figure .1, which mainly comprises an origin server, a cache server located on the edge of the network, a redirection Domain Name Server (DNS), and a content exchanging server. Wherein said origin server is responsible for generating server information content, said cache server is responsible for storing partial or entire information content in said origin server. When the DNS server explaining the address for the user judges that the website accessed by the user adopts CDN technology to distribute content, the URL information which is used for the content explaining of the user request is forwarded to the redirection DNS server, and the redirection DNS server sends the IP address of the Cache website which is closest to the DNS server forwarding the URL to the DNS server according to the received URL information, address information of the DNS server forwarding the URL, and the configuration of the Cache website when the CDN is configured. Said DNS server then forwards the received IP address to the user. Finally, the user completes connection with the "closer" Cache website utilizing the received IP address. By accepting the service provided by the closest Cache website, the pressure on the transmission of backbone IP networks is reduced, and the service quality is improved.

Content Exchange server and Content management server of the CDN are optional, wherein said Content Exchange Server is mainly deployed in the situation that one physical location has several Cache servers for fulfilling the function of load balance between Cache servers, and said Content Management server mainly manages the content stored in each Cache server of the whole CDN and institutes self-adaptive Cache strategy for each Cache server, in order to enhance service quality of Cache servers .

At present, the services of the broadband network and broadband streaming media applications such as Internet Protocol Television (IPTV, sometimes referred to as Inter^¬ connect Protocol Television or Broadband Television) , Voice over Demand (VoD) etc. are booming. The aforementioned broadband network and broadband streaming services have the following characteristics: the bandwidth occupied is large; the way of transmission is different from web browsing and downloading and transmits while playing, which occupies the web source for a long time. Therefore, the above characteristics mean the CDN network has some limitations when it deals with such wideband network service, which are as follows:

Firstly, the content distribution and updates in said CDN network are both done by the Central Node, and the node servers of every level have no ability to do content statistics and content updates automatically. This aggravates the burden of said Central Node and at the same time that of the backbone network in an IP network.

Secondly, the CDN network in the prior art exchanges information between the servers mainly to redirect the user' s request and the redirection is mainly done by the servers among networks instead of the end users. When new users or new network servers are added, the node servers in relation to end users or network servers must be reconnected due to the existence of many servers . Accordingly, the network structure must be adjusted and deployed again, which is a disadvantage for managing and expanding the network.

Summary of the Invention

Accordingly, the main aspect is to provide a content distribution system and a user request redirection method. Said system is primarily used for broadband network and streaming media application, and the node servers on the network can perform the content statistics and content updates automatically, and the end user per se can redirect the user' s request without depending on the network nodes to complete the redirection function.

In order to achieve the above objects, the technical solution of the present invention is implemented as follows: a Content Distribution System which is used in a network based on packet switch, a tree shape structure whose root node is a server is created, the leaf node servers of said tree shape structure are edge nodes, the non-leaf node servers of said tree shape structure store content and distribute the content to their son node servers .

Wherein each non-leaf node server of said tree shape structure distributes its partial or whole content to its son node servers. The said tree structure is either a physical structure, or a logical structure. Said tree shape structure node server and the end user are normally managed by one service provider' s platform, while the content of said tree shape structure node servers is managed by a content management system.

Moreover, said service provider' s platform divides the son node servers thereof according to a location information division method; and said service provider' s platform further sets up a location information for each end user, the location information being consistent with the structure of the corresponding leaf node server divided by said service provider's platform. In order to be consistent, the aforementioned service provider's platform further provides a location information number for each non-leaf node server and each leaf node server of said tree shape structure, and the number of each end user is set to be consistent with the number of the leaf node server to which the end user belongs.

Moreover, the above service provider' s platform generates a content server list for each end user, and stores said content server list . Said end user is connected to a network when said end user starts his/her computer. The above service provider' s platform authenticates said end user, and the content server list of said end user is then downloaded to said end user after authentication.

In the Content Distribution System of the present invention, each leaf node servers or non-leaf node servers updates their content according to the statistics request of said end user. Said content update is done periodically in the background (such as when not busy) , and a request is periodically made to the parent node server of the node servers or non-leaf node servers.

The present invention also provides a user request redirection method using said Content Distribution System , and the method includes the following steps:

(1) the end user sends a content request to the leaf node server to which said end user belongs;

(2) if said leaf node server has stored the content requested by the end user, said content is downloaded to said end user or played for said end user by way of stream media transportation; otherwise said end user sends a content request to the brother node server of said leaf node server;

(3) repeating the abovementioned step (2) until the requested content is downloaded to said end user or the last node server on the content server list of said end user has been visited, the said last node server is normally a root node server .

In the aforementioned method, the service provider' s platform creates a content server list for each end user, and said end user stores said content server list. Said end user is connected to a network when said end user starts his computer. Said service provider' s platform authenticates said end user, the content server list of said end user is then downloaded to said end user after authentication.

Moreover, the priority of the content server list of said end user is from leaf node to root node, and the request priority of the brother node for each node is higher than that of the parent node of said node. In the redirection method of the present invention, said leaf node servers or non-leaf node servers update their content according to the statistics request of said end user. Said content update is done periodically in the background (such as when not busy) .

It can be seen that the content distribution method and request redirection method in accordance with the present invention have the following advantages and features:

(1) First, the present invention provides a layered tree shape content distribution structure adapted to the broadband service such as IPTV and VOD etc. End users adopting said tree shape structure have a default edge node. The end user sends a content request first to the edge node. According to the 80/20 principle, the edge node can provide the great majority of content requested by the end user without sending a request to the upper node, hence the bandwidth of the IP network, especially the backbone network is saved.

(2) The present invention provides a layered tree shape structure, in which the edge nodes store the hottest and most popular contents, while the root node server stores the complete contents. Only when the edge nodes have no contents needed by users or the edge nodes are busy, are the other nodes searched for according to the redirection method provided by the present invention, thus the IP network resource is saved as much as possible.

(3) Since the present invention is a layered tree shape structure, in which the content on each layer node has backup on its upper level parent node, hence even if a server node is malfunctioning, the content thereof can be recovered from the backup server easily. Thus the structure adopting the present invention is highly reliable.

(4) In the present invention, server nodes update their content according to the content statistics request of said end user. Said statistics and update can be done when said server is not busy, for example, at night or when the access times are less, therefore, it does not affect the access of the user and the ability of the server node. (5) The present invention provides a tree shape structure. When the edge nodes and the non-leaf nodes must be further divided due to the great increase in end users, it is only necessary to change the corresponding edge nodes or the non- leaf nodes on the service provider' s platform without changing other nodes, which allows this tree shape structure to be managed and developed easily. At the same time, the above amendment with respect to the edge nodes and the non-leaf nodes can be performed on the service provider's platform easily. In general, the end user can download the newest content server list of this end user when he/she starts the computer, which makes the updating to the content server list of this end user be in time.

Brief Description of the Drawings

Figure 1 is a schematic view of a service model for providing an information service in the manner of server/client in the prior art;

Figure 2 is a schematic view for forming the network of the Content Distribution Network (CDN) in the prior art;

Figure 3 is a schematic view of an embodiment of the present invention.

Detailed Description

The present invention will be described in detail with reference being made to the accompanying drawing and a specific embodiment, and the specific embodiment is illustrative rather than limiting.

Figure 3 is a schematic view for depicting an embodiment of the present invention. First, a tree shape structure shown in Figure 3 is created on the server of a operator, in which the Beijing server is the root node, and the Chaoyang node, Haidian node, and Xicheng node are son nodes of the Beijing node. The Yayuncun node, Wangjing node, and Jiuxianqiao node are son nodes of the Chaoyang node, and the Zhongguancun node, Xuanyuan Road node, and Zizhuyuan node are son nodes of the Haidian node. Information such as IP address, port number, etc. of every node server on said tree is then managed by a VoD service provider's platform.

The end user is also managed by the aforementioned service platform. Since the user's location must be registered when the end user registers in a service, the service provider' s platform can know the end user's location. The service provider' s platform sets location information for each end user. For example, a user whose address is Wangjing registers in said VoD service, the "user location" in the end user location information is set as "Wangjing" by said platform.

The location information defined by the service provider' s platform shall be consistent with that defined for the server node (leaf node) . Since Chaoyang is divided by the platform into Yayuncun, Wangjing, Jiuxianqiao according to geographical location, end users shall also be distinguished according to locations such as Yayuncun, Wangjing, and Jiuxianqiao. In order to be consistent, the aforementioned service provider's platform may further provide a number for each non-leaf node server and each leaf node server of said tree shape structure, and the number of each end user is set be consistent with the number of the leaf node server to which the end user belongs. For example, the number of the Beijing node is 0, the number of the Chaoyang node is 11, the number of the Haidian node is 12, the number of the Xicheng node is 13, and the number of the Yayuncun node is 21, the number of the Wangjing node is 22, the number of the Jiuxianqiao node is 23.

Besides the aforementioned service provider' s platform, there is a Content Management System (CMS) to manage the content of each node server. First, said Content Management System distributes content to the Beijing root node. The content is then distributed to each son node of Beijing such as Chaoyang, Haidian, and Xicheng. The distribution starts with the root node, and from top to bottom. Thus, the Beijing root node stores the complete content, while the lower layer nodes, particularly the leaf nodes, store the hottest and most popular content. The node server also has a corresponding content server list, and each of the node servers sends a request to the upper layer node thereof actively, in the background or at night, for updating certain contents according to its own statistical information (for example, deleting the content which has not been accessed for a long time, or downloading the content which has been accessed more than a few times but is not on the present node server) . This update can be performed periodically.

Said service provider' s platform creates a content server list for each end user such as the aforementioned Wangjing user, and said platform stores said content server list. Said service provider' s platform authenticates said end user whenever users start the computer, then the content server list of said user is downloaded to said end user after authentication .

Since there is said server list to which said end user can request content on said server list, and said server list defines the request priority of each server node, hence the priority of each edge node server is: Wangjing node server, Yayuncun node server, Jiuxianqiao node server, Chaoyang node server, Haidian node server, Xicheng node server, Beijing node server. Accordingly, the end user located at Wangjing can request content according to the following steps:

(l)said end user sends a content request to a leaf node server, i.e. the Wangjing node server, to which said user belongs;

(2) if the Wangjing node server has stored the content requested by said end user, requested content is transmitted to said end user by way of streaming media; otherwise, since the Wangjing node server is busy or the Wangjing node server does not have the content requested by said end user, said end user sends a content request to a brother node server of said leaf node server such as the Yayuncun node server;

(3) if the Yayuncun node server is busy or said server does not have the content requested by said end user, said end user sends a content request to another brother node such as the Jiuxianqiao node server;

(4) if the Jiuxianqiao node server is busy or said server does not have the content requested by said end user, said end user sends a content request to the parent node server of said edge node server, i.e. the Chaoyang node server;

(5) if the Chaoyang node server is busy or said server does not have the content requested by said user, said end user sends a content request to a brother node of said Chaoyang node server, for example, the Haidian node server;

(6) the Haidian node server has stored the content requested by said user, the requested content is then downloaded to said end user.

As can be seen from said embodiment, the present invention provides a layered tree shape content distribution structure adapted to broadband service such as IPTV and VOD etc. End users adopting said tree shape structure have a default edge node. The edge nodes store the hottest and most popular contents, while the root node server stores the complete contents. The end user sends a content request first to the edge node. According to the 80/20 principle, the edge node can provide the great majority of content requested by the end user without sending a request to the upper node. Only when the edge nodes have no content needed by the users or the edge nodes are busy, are the other nodes searched for according to the redirection method provided by the present invention. Thus the bandwidth of the IP network, especially the backbone network is saved.

Claims

1. A content distribution system which is used in a network based on packet switch, characterized in that a tree shape structure whose root node is a server is created, the leaf node servers of said tree shape structure are edge nodes, the non- leaf node servers of said tree shape structure store content and distribute the content to their son node servers.

2. The system as claimed in claim 1, characterized in that the non-leaf node servers of said tree shape structure distribute part or all of its content to their son node servers.

3. The system as claimed in claim 1 or 2, characterized in that said tree shape structure node servers and end users are managed by a service provider's platform.

4. The system as claimed in claim 1 or 2, characterized in that the content of said tree shape structure node servers is managed by a content management system.

5. The system as claimed in claim 3, characterized in that said service provider' s platform divides said son node servers according to a location information dividing method.

6. The system as claimed in claim 5, characterized in that said service provider' s platform provides a location information number for each non-leaf node server and each leaf node server of said tree shape structure.

7. The system as claimed in claim 5, characterized in that said service provider' s platform sets up a location information for each end user, the structure of said location information being consistent with the structure of the corresponding leaf node server which is divided by said service provider's platform.

8. The system as claimed in claims 1, 2, 4, 5, 6, or 7, characterized in that said leaf node servers or non-leaf node servers update their content according to the statistics request of said end users.

9. The system as claimed in claim 7, characterized in that said service provider' s platform creates a content server list for each end user, and said end user stores said content server list .

10. The system as claimed in claim 9, characterized in that said service provider' s platform authenticates said end user, then the content server list of said end user is downloaded to said end user.

11. A user request redirection method using said content distribution system, characterized in that the method includes the following steps :

(1) an end user sends a content request to the leaf node server to which said end user belongs;

(2) if said leaf node server has stored the content requested by the end user, said content is downloaded to said end user or is played for said end user by way of stream media transportation; otherwise said end user sends a content request to a brother node server of said leaf node server;

(3) repeating the abovementioned step (2) until the requested content is downloaded to said end user or the last node server on the content server list of said end user has been visited.

12. The system as claimed in claim 11, characterized in that a said content server list is created for each end user and stored by a service provider's platform.

13. The system as claimed in claim 12, characterized in that said service provider' s platform authenticates said end user, then the content server list of said end user is downloaded to said end user.

14. The system as claimed in claim 12, characterized in that the priority of the content server list of said end user is from leaf node to root node, and the request priority of the brother node for each node is higher than that of the parent node of said node .

15. The system as claimed in claims 11, 12 or 14, characterized in that said leaf node servers or non-leaf node servers update their content according to the statistics request of said end user .

16. The system as claimed in claim 15, characterized in that said leaf node servers or non-leaf node servers update their content periodically according to the statistics request of said end users .