KR20140032064A - Contents delivery service method using contents sharing, and cache apparatus therefor - Google Patents

Abstract

The present invention relates to a content transmission service method and a cache device therefor. Multiple cache devices distributed in a network are grouped into multiple groups, and a master cache device and a slave cache device which is a lower node of the master cache device are set in each group. Multiple master cache devices are hierarchically divided and connected in a tree structure, and a content request message by a terminal device and a content response message in response to the message are transmitted to a content providing server and the terminal device by more than one master cache device. The master cache device receiving the content response message stores content location information indicating a cache device which caches the content extracted from the content response message. When the content request message is received, the master cache device determines whether a cache hit for the requested content is performed and whether the content location information is stored. In the case of a cache hit, the master cache device transmits a redirection message changing a content request location to the terminal device, and the terminal device receives content from another cache device. [Reference numerals] (101) Master cache device 1; (102) Master cache device 2; (103) Master cache device 3; (106) Slave cache device 3; (200) Content providing server; (301) Terminal device 1; (302) Terminal device 2

Description

Content delivery service method using contents sharing, and cache apparatus therefor}

The present invention relates to a content delivery service for reducing traffic by preventing duplicate content delivery in a network. More particularly, the present invention relates to a content delivery service by efficiently sharing limited cache capacity by sharing cached content among cache devices. The present invention relates to a content transmission service method capable of providing a cache device.

Recently, due to the proliferation of smart phones with improved performance and the proliferation of content providers based on them, the traffic of mobile communication networks is increasing. Accordingly, web download, video, audio ( Service quality problems due to a decrease in the transmission speed of contents such as audio, images, applications, etc. are becoming an issue.

In particular, with the development of content delivery technology and the demand for high quality services by users, large-scale content transmission becomes more frequent in online video services such as VOD (Video On Demand) and Live Streaming, music streaming, file upload and file download. have.

However, these content providing services typically deliver duplicate content to users in the same domain or in the same wireless coverage, and the share of network traffic is gradually increasing as the usage increases.

In this way, in the situation where the traffic of the communication network is rapidly increasing due to the transmission of the large amount of contents, the transmission of the duplicated contents further increases the traffic load of the communication network, so efforts to reduce the traffic through prevention of such duplicated transmission are required.

Accordingly, in order to stably deliver various contents including videos such as movies, music videos, etc. to users while reducing traffic in a network, a contents delivery network (CDN) technology has been proposed. Stores the content in the cache device, selects the optimal cache server among a plurality of cache servers through a load balancer such as a global load balance (GLB) server, and delivers the requested content to the user's terminal through the selected cache server. Is implemented.

In addition, recently, the cache server collects and stores content transmitted from the content providing server to the terminal device according to a preset caching policy, and when a request for the corresponding content occurs, the content is stored on the terminal device instead of the content providing server. Transparent CDN technology is also used.

As described above, in the CDN implementation of reducing traffic through a plurality of cache servers, the larger the storage capacity of the cache server, the more the content can be stored to increase the cache hit rate and thereby improve the transmission service quality. As the cost of construction increases, the storage capacity of the cache server cannot be increased.

Accordingly, there is a need for a method for caching contents more efficiently by using a plurality of cache servers and providing cached contents to a terminal device.

Accordingly, the present invention provides a method for efficiently using a storage space in a content delivery service, and in particular, a content delivery service method for more efficiently using a limited amount of storage space by sharing cached content among cache devices, We want to provide a cache device.

According to an aspect of the present invention, there is provided a means for solving the above problems, the method comprising: storing, by a master cache device, one or more pieces of information among one or more slave cache devices, a higher level master cache device, and a lower level master cache device; Receiving a content request message from a lower node which is one of the at least one slave cache device and the lower level master cache device; Determining whether a cache hit is requested for the requested content; If not a cache hit, sending the content request message to a higher level master cache device; If it is a cache hit, it provides a content transmission service method comprising the step of transmitting a redirect message for changing the content request location to itself to the lower node.

The content transmission service method may include: receiving, by the master cache apparatus, a content response message from a content providing server or a higher level master cache apparatus; Extracting and storing content location information indicating a cache device from which the content response message is to be cached; And transmitting the content response message to the lower node.

The content transfer service method may further include: receiving, by the master cache device, a redirect message from a higher level master cache device; Extracting and storing content location information indicating a cache device in which content is cached from the redirection message; The method may further include transmitting the redirection message to the lower node or the corresponding terminal device.

The content transfer service method may further include, if not a cache hit, checking, by the master cache device, whether a higher level master cache device exists; And if the high level master cache device does not exist, transmitting the content request message to a content providing server by the master cache device.

The content transmission service method may include: if it is not a cache hit, checking, by the master cache apparatus, whether content location information on the requested content exists; If the content location information is present, the master cache device may further include generating a redirect message for changing the content request location to the cache device corresponding to the content location information and transmitting the redirect message to the lower node or the terminal device. .

The method may further include: checking a request number of content corresponding to the content location information before transmitting the content transmission service method and the redirection message to a lower node or a terminal device; Requesting content from a cache device corresponding to the content location information if the number of requests is greater than or equal to a reference value; Receiving a content response message sent from the cache device in response to the request, extracting and caching content from the content response message; And transmitting the received content response message to the lower node or the terminal device.

In addition, the present invention as a solution to the above problem, the slave cache device, the step of storing the setting information of the master cache device; Receiving a content request message of the terminal device; Determining whether the requested content is cache hit; Extracting cached content to generate a content response message if the cache is hit, and transmitting the generated content response message to the terminal device; And if not a cache hit, transmitting the content request message to a content providing server through the master cache device.

The content transmission service method may include: receiving, by the slave cache device, a content response message for the requested content through the master device; Extracting and caching content from the content response message; The method may further include transmitting the content response message to the terminal device, and when the slave cache device receives the redirect message from the master device, transmitting the redirection message to the terminal device. have.

In addition, the present invention as a solution to the above problem, comprising the steps of grouping a plurality of cache devices distributed in a network into a plurality of groups; Setting a master cache device and a slave cache device that is a subordinate node of the master cache device for each group; Hierarchically dividing the plurality of master cache devices into a tree structure; Transmitting the content request message of the terminal device and the corresponding content response message to the content providing server and the terminal device through one or more master cache devices connected in a tree structure; Receiving a content response message, the master cache device storing content location information indicating a cache device to cache content extracted from the content response message; And determining, by the master cache apparatus that has received the content request message, whether the cache is hit for the requested content. And in the case of a cache hit, transmitting a redirection message for changing the content request location to the terminal device to the terminal device.

In the content delivery service method, the setting of the master cache device and a slave cache device that is a lower node of the master cache device may include: cache capacity, hardware performance, service target terminal device, for a plurality of cache devices belonging to each group; The master cache device and the slave cache device may be set by comparing cache performance information including one or more of the number of.

In addition, the present invention as a means for solving the above problems, a communication interface for transmitting and receiving data through the network; A storage unit for storing one or more of cached content, cache connection information defining other cache devices connected in a tree structure, and content location information about content stored in other cache devices; Check whether the master mode or the slave mode, and in the master mode, stores information about at least one of the at least one slave cache device, a higher level master cache device connected in a tree structure, and a lower level cache device as the cache connection information. In response to the cache hit being determined by the terminal device whether the cache is hit for the requested content, the controller is configured to transmit a redirection message for changing the content request position to the terminal device through the one or more slave cache devices or the lower level master cache device. It provides a cache device comprising a.

In the master mode, the controller of the cache device receives the one or more slave cache devices or the lower level master cache devices by receiving a redirect message for changing a content response message or a content request location from the high level master cache device or the content providing server. While transmitting to the terminal device through the content response message or the redirect message, the content location information indicating the cache device to be cached content may be extracted and stored in the storage unit.

The controller of the cache apparatus further checks whether the content location information on the requested content exists in the storage unit when the cache hit is not in the master mode, and requests the content when the content location information exists. A redirection message for changing a location to a cache device corresponding to the content location information may be transmitted to the corresponding terminal device through the one or more slave cache devices or the lower level master cache device.

In addition, the controller of the cache apparatus determines whether to cache the content according to at least one of the number of request of the content and the location of the terminal device that requested the content, and if it is determined that the content is cached, instead of transmitting the redirection message. The content may be received from the cache device corresponding to the content location information and transmitted to the one or more slave cache devices or the lower level master cache device.

In addition, when the controller of the cache apparatus receives the content request message from the terminal apparatus, the controller determines whether one or more of the requested content is cache hit and whether the content location information is present. If it is transmitted to the device and the content location information is not cache hit, but the content location information exists, a redirect message for changing the content request location to the cache device corresponding to the content location information may be transmitted to the terminal device.

In addition, in the slave mode, the controller of the cache device stores the configuration information of the master cache device, which is the upper node, as cache connection information, receives a content request message from the terminal device, determines whether the content cache is hit, and the cache hit. In this case, the cached content is transmitted to the terminal device, and if it is not a cache hit, the content request message is transmitted to the master cache device, and, in the slave mode, a content response message of the content providing server through the master cache device. When receiving the content response message, the content response message may be transmitted to the terminal device, and content data may be extracted from the content response message and stored in the storage unit.

According to the above-described problem solving means, in the content delivery service, a plurality of cache devices distributed in a network are hierarchically divided and connected in a tree structure, and the cache devices provide information about cached content. By enabling sharing, even if you are not caching the content requested for a particular cache device, you can ensure that the content is served through another cache device that is caching that content, resulting in more efficient storage space for the cache devices. In addition, there is an excellent effect that can further distribute the traffic concentrated to the content providing server.

1 is a block diagram showing the configuration of a content delivery system according to an embodiment of the present invention.
2 is a diagram illustrating an example of a content delivery flow in a content delivery system according to an exemplary embodiment of the present invention.
3 is a message flow diagram illustrating a content delivery process in a content delivery system according to an embodiment of the present invention.
4 is a block diagram illustrating a configuration of a cache apparatus according to an exemplary embodiment of the present invention.
5 to 9 are flowcharts illustrating a content delivery service method according to an exemplary embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, detailed description of well-known functions or constructions that may obscure the subject matter of the present invention will be omitted. It should be noted that the same constituent elements are denoted by the same reference numerals as possible throughout the drawings.

1 is a block diagram showing the configuration of a content delivery system according to an embodiment of the present invention.

Referring to FIG. 1, a content delivery system according to an embodiment of the present invention includes a plurality of cache devices 101 to 109 distributed in a network. In addition, the reference numeral 200, shown in Figure 1 is a content providing server for providing content through a network, in particular, a server device for providing content to a plurality of terminal devices (301,302) through the content delivery system according to the present invention. That is, the content providing server 200 is a content provider side device that provides original data of content transmitted to the terminal devices 301 and 302 through the content delivery system according to the present invention. For example, the content providing server 200 may be a video content providing server or a video sharing service server such as a video on demand (VOD).

The terminal devices 301 and 302 are terminal devices that request content provided by the content providing server 200 through a network to which the content delivery system according to the present invention is applied, and receive and provide the requested content to a user. The terminal devices 301 and 302 may be any electronic / information communication device including communication functions such as, for example, a desktop PC, a notebook computer, a tablet PC, a smart phone, a personal digital assistant (PDA), and an Internet TV (smart TV). It can be anything.

In addition, the network to which the present invention is applied is not only an IP-based wired communication network such as the Internet network, but also a long term evolution (LTE) network, a mobile communication network such as a WCDMA network, various types of wireless networks such as a Wi-Fi network, and these It can be made of a combination of. That is, the content transmission system according to the present invention can be applied to both wired and wireless communication networks without discrimination.

The plurality of cache apparatuses 101 to 109 according to the present invention are distributed and distributed in a network, and the contents providing server 200 stores the contents to be provided to a user for a temporary or predetermined time period, and from the specific terminal apparatuses 301 and 302. When the content is requested, the content is stored in its place on the behalf of the content providing server 200 to the terminal device (301, 302).

In particular, the plurality of cache devices 101 to 109 may be distributed at the edge of the network, and the network may include one or more wireless or wired access networks to which the terminal devices 301 and 302 are connected, and a core connecting the plurality of access networks. In the case of a network, it is arranged at an edge of a core network, more specifically, at an edge of a core network to which an access network is connected, and monitors content requests of terminal devices connected to a corresponding access network, respectively, to cache the requested content. In this case, the cached content is provided to the corresponding terminal device, and if it is not cached, the content providing server 200 is requested to transmit and receive the content.

The present invention provides a content delivery service through the plurality of cache devices 101 to 109, and more efficiently uses the storage space of each cache device 101 to 109 and concentrates traffic on the content providing server 200. In order to distribute, the plurality of cache devices 101 to 109 are grouped into a plurality of groups, the master cache devices are dynamically set for each group, and the master cache devices are divided hierarchically and connected in a tree structure. The master cache device corresponding to the root node in the tree structure is connected with the content providing server 200. Here, the remaining cache devices other than the master cache device in each group are called slave cache devices. In the embodiment illustrated in FIG. 1, cache devices 101 to 103 are set as master cache devices, and cache devices 104 to 109 are set as slave cache devices. In addition, the master cache devices 101 to 103 are divided into first to third master cache devices 101 to 103 for convenience.

The first to third master cache devices 101 to 103 may be set dynamically, and may be changed to other cache devices according to whether a service environment changes or a failure occurs.

The first to third master cache devices 101 to 103 may be set by comparing cache performance information including one or more of cache capacity, hardware performance, and the number of terminal devices to be serviced. In addition, the setting of the master cache device and the tree structure setting between the master cache devices may be set based on various methods, for example, manual setting by an administrator, Open Shortest Path First (OSPF), and the like. OSPF is a routing protocol that recognizes the least expensive paths to deliver packets on each link and creates the tree topology of the shortest path. Here, the cost may be calculated based on the band, distance, etc. of the strong link. Since such OSPF is already known, a detailed description thereof will be omitted. The present invention can set the master cache devices (101 to 103) of the plurality of cache devices using the OSPF method, and set the tree connection structure between the first to third master cache devices (101 to 103). In addition, the preset first to third master cache devices 101 to 103 may be changed to another cache device when a failure occurs.

According to the present invention, a plurality of cache devices of a content delivery system are classified into a plurality of groups (groups A, B, and C), and one master cache device 101 to 103 is set for each group. The configured first to third master cache devices 101 to 103 are connected to slave cache devices 104 to 109, which are the remaining cache devices of the corresponding group, respectively, and are also connected to other master cache devices in a tree structure. Accordingly, the first to third master cache devices 101 and 103 are configured with one or more of a higher level master cache device as an upper node in the tree structure and a lower level master cache device as a lower node in the tree structure.

In the embodiment of FIG. 1, the first and second master cache devices 101 and 102 become lower level master cache devices of the third master cache device 103, and the third master cache device 103 is the top of the tree structure. As a root node located at, the first node becomes a high level master cache device of the first and second master cache devices 101 and 102 and is connected to the content providing server 200.

In this state, the content request message of the terminal devices 301 and 302 detected by the specific cache devices 101 to 109 is one of the first to third master cache devices 101 to 103 connected in a tree structure. Through the above it is transmitted to the content providing server 200, the response message of the content providing server 200 is also transmitted through the same path. As described above, while the content request message of the terminal devices 301 and 302 and the corresponding content response message are transmitted through the one or more master cache devices 101 to 103 connected in a tree structure, each master cache device 101 to 103 may be used. Content location information indicating a cache device for caching the corresponding content is extracted from the received content response message and stored. When the content request message is received, the cache server checks whether the requested content is cached and whether the content location information is stored. When the cache hit or the content location information is stored, the cache request or the content location information is stored. The redirection message for changing the content request location is transmitted to the corresponding terminal device (301, 302). Accordingly, the terminal devices 301 and 302 may request a cache device that actually stores the corresponding content and receive the content.

Herein, the message related to the content request may be transmitted according to the HTTP protocol. Specifically, the content request message may be an HTTP GET message, the content response message may be an HTTP RESPONSE message, and the redirection message may be an HTTP REDIRECT message. .

Hereinafter, in the content delivery system according to the present invention, a content delivery process will be described by way of example.

2 is a diagram illustrating an example of a content delivery flow in a content delivery system according to an exemplary embodiment of the present invention. In addition, in the following description, the terminal devices 301 and 302 are divided into first and second terminal devices for convenience. In addition, it is assumed that specific content is initially requested through the first terminal device 301, and then the second terminal device 302 requests the same content.

In this case, all the cache devices, that is, the first to third master cache devices 101 to 103 and the slave cache devices 104 to 109 detect the content request message of the specific terminal device, and request the content request message from the corresponding content request message. First, it is determined whether the content is stored, that is, whether or not the cache hit, and if the cache hit, the cached content is extracted and transmitted to the terminal device. Here, the determination of whether or not the cache hit, may be made in a variety of ways, such as URL-based, content-based. The first to third cache apparatuses 101 to 103 may further determine whether the location information of the requested content is stored if the cache hit is not determined after determining whether the cache hit is made.

Therefore, when the content request message is detected, the first master cache device 101 first determines whether the content requested in the content request message is stored, that is, whether the cache is hit. Here, if the requested content is cached, the cached content may be extracted and immediately provided to the first terminal device 301, and the content request message is not transmitted to another master cache device or the content providing server 200. .

On the other hand, when the first master cache apparatus 101 does not store the requested content, the first master cache apparatus further checks whether location information on the requested content is stored, and thus the content location information is not stored. The device 101 transmits the content request message of the first terminal device 301 to the third master cache device 103, which is a high level master cache device connected in a tree structure. In addition, the third master cache device 103 also determines whether the cache is hit for the requested content and whether the content location information is stored. Similarly, if none of the requested content and its location information are stored, 1 The content request message of the terminal device 301 is transmitted to the higher node. In this case, since the third master cache device 103 corresponds to a root node in a tree structure, the content request message of the first terminal device 301 is transmitted from the third master cache device 103 to the content providing server 200. (①).

Accordingly, the content providing server 200 generates and transmits a content response message including the requested content. The content response message is generated through the third master cache device 103 and the first master cache device 101. 1 is transmitted to the terminal device 301 (2).

At this time, the cache device that detects the content request message of the first terminal device 301, that is, the first master cache device 101 extracts and stores data of the requested content from the content response message. In addition, each of the master cache device located on the transmission path of the content response message, that is, the third master cache device 103, may each store content location information, that is, content to be cached from the content response message (first master cache device). (101) extract and store the information.

In this state, when the second terminal device 302 requests the same content and the slave cache device 106 of the group B area detects the content request message of the second terminal device 302, the slave cache Since the device 106 does not store the content requested by the second terminal device 302, the content request message of the second terminal device 302 to the second master cache device 102, which is the master node of the corresponding group B. Send it. Subsequently, the second master cache device 102 checks whether or not the cache hit and the location information of the corresponding content, and since neither the cache hit nor the content location information exist, the third master cache device 103 which is an upper node in the tree structure. In step 3, the content request message of the second terminal device 302 is transmitted.

In this case, since the third master cache device 103 stores the content location information of the corresponding content in response to the content request of the first terminal device 301, the content is transferred to the cache device corresponding to the content location information. A redirection message (HTTP REDIRCT message) for changing the request location is transmitted to the second terminal device 302, whereby the second terminal device 302 receives the corresponding content from the first master cache device 101 ( ④).

A content transmission process according to an embodiment of the present invention will be described in more detail with reference to the message flow chart of FIG. 3.

3 is a message flow diagram illustrating a content delivery process in a content delivery system according to an embodiment of the present invention.

Referring to FIG. 3, the content request message (HTTP GET message) of the first terminal device 301 is detected by the first master cache device 101 according to the allocation of a service area, and the requested content and its associated content. Since the content location information is not stored, the content response message generated by the content providing server 200 is transmitted to the content providing server 200 through the upper node of the tree structure, that is, the third master cache device 103. (HTTP RESPONSE) is similarly transmitted to the first terminal device 301 via the third master cache device 103 and the first master cache device 101 (S101). In this case, the first master cache device 101, which is a cache device that detects the content request message of the first terminal device 301, extracts and stores data of the requested content from the content response message, and stores the data of the content response message. The third master cache device 103, which is a master cache device located on the transmission path, extracts content location information, that is, information on a cache device (first master cache device 101) to which content is cached, from a content response message. Save it.

In this state, when the content request message (HTTP GET) of the second terminal device 302 requesting the same content is transmitted, the slave cache device 106 of the group B in charge of the corresponding area detects the above. The content request message (HTTP GET) of the second terminal device 302 is transmitted to the second master cache device 102, which is an upper node of the corresponding group B, and the second master cache device 102 determines whether the corresponding content is cache hit. And since the location information is not cache hit and no content location information exists, the content request message of the second terminal device 302 is transmitted to the third master cache device 103 and the third master cache device. Since the 103 stores the content location information indicating that the first master cache device 101 stores the content, the HTTP RED for changing the content request location using the content location information. The IRECT message is transmitted, which is transmitted to the second terminal device 302 through the second master cache device 102 and the slave cache device 106 (S103). In this case, the second master cache device 102 receiving the HTTP REDIRECT message may extract and store information about a storage location of the corresponding content, that is, information about the first master cache device 101, from the corresponding HTTP REDIRECT message.

Upon receiving the HTTP REDIRCT message, the second terminal device 302 transmits an HTTP GET message for requesting the corresponding content to the changed address recorded in the message, that is, the first master cache device 101, and the first master. An HTTP RESPONSE message including the requested content is received from the cache device 101 (S105).

In this state, when the second terminal device 302 requests the same content again, the subsequent HTTP GET message of the second terminal device 302 is the second master cache device through the slave cache device 106 as before. In step S103, the second master cache apparatus 102 obtains the content location information of the corresponding content in step S103. Therefore, the second master cache apparatus 102 does not transmit the HTTP GET message of the second terminal apparatus 302 to a higher node. Instead, an HTTP REDIRCT message for changing the content request location to the first master cache device 101 is generated and transmitted to the second terminal device 302 through the slave cache device 106 (S107).

Accordingly, the second terminal device 302 transmits an HTTP GET message requesting the next data for the same content to the first master cache device 101, and an HTTP RESPONSE message including data of the corresponding content from the first master cache device. Receive (S109).

While the steps S107 to S109 are repeatedly executed and the content is transmitted from the first master cache device 101 to the second terminal device 302 through redirection, the second master cache device 102 for redirecting the content includes: Instead of sending an HTTP REDIRECT message according to a predetermined criterion, the user may determine whether to cache content directly. For example, the second master cache device 102 checks the redirection number for the same content request, and if the redirection number exceeds the reference number, the second master cache device 102 corresponds to the first master cache device 101 corresponding to the content location information. The HTTP GET message may be directly transmitted, and an HTTP RESPONSE message including content data may be received from the first master cache device 101 and transferred to the slave cache device 106 which is a lower node (S111). In this case, the slave cache device 106 may extract and cache the corresponding content data while delivering the received HTTP RESPONSE message to the second terminal device 302. Therefore, when the same content is requested later in the region of the group B, the slave cache device 106 may immediately transmit the requested content.

Next, the configuration and operation of the cache apparatus that performs the above-described process will be described.

4 is a block diagram illustrating a configuration of a cache device 100 according to an exemplary embodiment of the present invention. The cache device 100 shown here is represented by a concept including both the master cache devices 101 to 103 and the slave cache devices 104 to 109 of FIG. 1. That is, in FIG. 4, the cache apparatus 100 may operate as the master cache apparatuses 101 to 103, or may operate as the slave cache apparatuses 104 to 109 in some cases.

Referring to FIG. 4, the cache device 100 according to the present invention includes a communication interface 110, a storage 120, and a controller 130.

The communication interface 110 is a component for transmitting and receiving data through a network to which the content delivery system according to the present invention is applied. In more detail, the communication interface 110 may receive a content request message and a content response message transmitted and received through a network, and transmit the content request message and the content response message to another cache device or the content providing server 200 or the terminal device 301 or 302.

The storage unit 120 is a component for storing necessary data and programs for operating the cache apparatus 100. The storage unit 120 basically stores the content data 121 cached by the cache apparatus 100, that is, the content providing server 200. The content data 121 to be provided to the first and second terminal devices 301 and 302 is stored. In addition, when the cache device 100 is set as a master cache device (hereinafter, referred to as a master mode), the storage 120 may further store content location information 122. Here, the content location information 122 is location information of content transmitted through the plurality of cache devices 100 according to the present invention, specifically, information of a cache device in which the corresponding content is stored, in particular, content stored in another cache device. Means location information. In addition, the storage unit 120 may further store cache connection information 123 required to connect with other cache devices to form a tree connection according to the present invention. When the cache device 100 is in the master mode, the cache connection information 123 may be configured for at least one of a slave cache device, a higher level master cache device and a lower level master cache device corresponding to a higher node and a lower node in the tree structure. If the cache device 100 is not in the master mode, that is, set as a slave cache device (referred to as a slave mode), the cache connection information 123 may include a master of a group to which it belongs. Contains setting information of the cache device.

The controller 130 is a means for controlling the first half of the caching service operation by the cache apparatus 100, and the operation may vary according to an operation mode of the cache apparatus 100, that is, a master mode / slave mode.

First, when the slave mode is set, the controller 130 obtains information on the master cache device of the group to which the group belongs as cache connection information 123 and stores the information in the storage 120. The information on the master cache device may include identification information or address information (eg, an IP address) of the cache device set as the master cache device. In addition, the device detects a content request message of an arbitrary terminal device, more specifically, a terminal device located in its own area through the corresponding network, and checks whether a cache hit for the content requested by the content request message occurs, that is, the requested content. Determines whether is stored in the storage unit 120, and if the cache is hit, the requested content is extracted from the storage unit 120 and transmitted to the corresponding terminal device. On the other hand, if it is not a cache hit, that is, if the requested content is not stored in the storage unit 120, the detected content request message is transmitted to the master cache device defined in the cache connection information 120.

Thereafter, when the controller 130 receives a content response message corresponding to the requested content from the master cache device, the controller 130 extracts the corresponding content data while transmitting the received content response message to the corresponding terminal device and stores the content data. 120).

On the other hand, when the master mode is set, the controller 130 obtains and stores information about one or more of one or more slave cache devices, a higher level master cache device, and a lower level master cache device as cache connection information 123.

In addition, the controller 130 receives the content request message through the communication interface unit 100 and determines whether the content requested in the content request message is stored in the storage unit 120 (ie, a cache hit). In this case, the content request message may be transmitted from a terminal device, a slave cache device, or a lower level master cache device. Basically, even in the master mode, when the cache apparatus 100 directly receives the content request message of the terminal device, the controller 130 extracts the corresponding content from the storage unit 120 when the cache hit is determined as a result of the cache hit and the terminal device. If it is not a cache hit, the corresponding content request message is transmitted to an upper node, that is, the upper level master cache device recorded in the cache connection information 123.

On the other hand, when the requested content is cached in the content request message transmitted from the slave cache device or the lower level master cache device, the controller 130 generates a redirection message for changing the content request location to the slave cache device or It transmits to the terminal device through the lower level master cache device. Accordingly, the content request message is directly received from the terminal device to provide the content.

In addition, if the requested content is not a cache hit in the content request message transmitted from the slave cache device or the lower level master cache device, the controller 130 further checks whether the content location information of the requested content is stored. Here, when the content location information is stored, the controller 130 generates a redirect message for changing the content request location to the cache device corresponding to the content location information, and transmits the redirection message to the slave cache device or the lower level master cache device. If the content location information is not stored, the content request message is transmitted to the high level master cache device recorded in the cache connection information 123. At this time, if there is no information on the upper level master cache device in the cache connection information 123, and transmits the content request message to the content providing server 200.

In addition, the controller 130 may receive a content response message or a redirect message from the content providing server 200 or the higher level master cache device through the communication interface 110, in which case, the controller 130 receives the content response message. The content response message or the redirection message is transmitted to its own lower node, that is, the slave cache device or the lower level master cache device, and the content location information is extracted from the content response message or the redirection message and stored in the storage 120. .

Subsequently, the content delivery service method performed through the plurality of cache apparatuses 100 configured as described above will be described in sequence.

5 to 9 are flowcharts illustrating a content delivery service method according to an exemplary embodiment of the present invention. In addition, the following description is made based on the content delivery system shown in FIG. 1.

First, referring to FIG. 5, in the content delivery service method according to the present invention, a plurality of cache apparatuses 100 (101 to 109) distributed and distributed in a network may be predetermined criteria (for example, IP address, distance, region, etc.). In step S201, the master cache devices 101 to 103 and the slave cache devices 104 to 109 that are lower nodes of the master cache device are set for each group (S203). In step S203, the setting of the master cache device and the slave cache device may be performed by comparing cache performance information including one or more of cache capacity, hardware performance, and the number of terminal devices to be serviced, for a plurality of cache devices belonging to each group. It can be made by. For example, a cache device with a large cache capacity and a large number of connected terminal devices may be set as a master cache device.

Then, the plurality of master cache devices 101 to 103 are hierarchically divided and connected in a tree structure (S205). The step S205 may be performed based on an OSPF method or an IP address, and the slave cache devices 104 to 109 store information on the master cache devices 101 to 103 which are their upper nodes, respectively, and each master cache. The devices 101 to 103 respectively provide information about the slave cache devices 104 to 109 and other master cache devices connected to the upper node or the lower node in the tree structure, that is, the upper level master cache device and the lower level master cache device. It can be done by setting the information about.

The content delivery service method according to the present invention is based on such a hierarchical tree structure-based content delivery system, in which the operation is divided into a master cache device and a slave cache device.

Accordingly, each cache device 100 (101 to 109) may check whether the slave cache device is the master cache device before performing the content transfer service.

When specific cache devices 101 to 103 are set as master cache devices (S301), the master cache devices 101 to 103 may include one or more slave cache devices, a higher level master cache device, and a lower level corresponding to a group to which they belong. Configuration information about one or more of the level master cache devices may be obtained and stored as cache connection information 123 (S303).

Subsequently, when the master cache apparatuses 101 to 103 receive an arbitrary content request message through the communication interface unit 100 (S305), the master cache apparatuses 101 to 103 store the content requested by the content request message in their storage unit 120. It determines whether it is (ie, cache hit) (S307).

In this case, when the content requested by the received content request message is cache hit, the master cache apparatuses 101 to 103 check whether the received content request message is directly received from the terminal apparatuses 301 and 302 (S309). ).

As a result of the check, if the content request message is directly received from the terminal device 301 or 302, a content response message is generated, and the data of the cache hit content is transmitted to the corresponding terminal device 301 or 302 through the content response message. (S313, S314).

On the other hand, if the content request message is not directly received from the terminal device 301 or 302, that is, the content request message transmitted from the lower node, the slave cache devices 104 to 109, or another lower level master cache device, the content request location. Generates a redirect message to change the value to itself and transmits the redirection message to the lower node, the slave cache devices 104 to 109, or the lower level master cache device (S311).

In addition, in step S307, if the content requested in the received content request message is not stored, the master cache apparatus (101 ~ 103), as shown in Figure 7, the content location for the content requested in the content request message Further check whether the information he has (S401).

As a result of the check, if the user has the content location information, the sub-node, that is, the terminal device 301 or 302 or the slave cache device may change the content request location to the cache device corresponding to the content location information. 104 to 109) or a lower level master cache device (S403). The redirection message transmitted to the slave cache devices 104 to 109 or the lower level master cache device is transmitted to the corresponding terminal devices 301 and 302 through each node located on the tree connection structure.

On the other hand, as a result of checking in step S401, if the content location information for the requested content is not stored, the master cache device (101 to 103), the received content request message is a higher level master cache device or content providing server ( 200). More specifically, the master cache devices 101 to 103 are upper nodes, and check whether the higher level master cache device exists in the cache connection information 123 (S405), and if the higher level master cache device exists, The content request message is transmitted to the level master cache device (S407). If the high level master cache device does not exist, the content request message is transmitted to the content providing server 200 since it is a root node of a tree structure (S409). ).

By the above-described process, the content request message of the terminal device (301, 302) is delivered to the content providing server 200 through a plurality of cache devices, that is, a plurality of master cache devices (101 ~ 103) connected in a tree structure do.

Accordingly, the content providing server 200 generates a content response message and transmits data of the requested content in the content response message, wherein the content response message is connected to a tree structure in which the content request message has been previously transmitted. The master cache devices 101 to 103 are transmitted to the terminal devices 301 and 302.

Accordingly, as illustrated in FIG. 8, the master cache apparatuses 101 ˜ 103 may receive a content response message from the content providing server 200 or the upper level master cache apparatus (S501).

In this way, the master cache apparatuses 101 to 103 that have received the content response message first check whether there is a lower node to which the content response message is to be transmitted (S503). The presence or absence of the lower node may be determined by determining whether the terminal devices 301 and 302, which are destinations of the content response message, are connected to the terminal device.

If the terminal devices 301 and 302 are not connected to the master device, the master cache devices 101 to 103 extract and store content location information, that is, a cache device to store the corresponding content from the received content response message. In addition, the content response message is transmitted to a lower node, that is, a lower level master cache device or a slave cache device 104 to 109 (S507).

On the contrary, if the terminal devices 301 and 302 are connected to themselves, since there is no lower node to transmit the received content response message, the content data is extracted from the content response message and cached (S509). The content response message is transmitted to the lower node, that is, the lower level master cache device or the slave cache devices 104 to 109 so as to be transmitted to the corresponding terminal device 301 or 302 (S511).

In addition, the master cache apparatuses 101 ˜ 103 may receive the redirection message transmitted by the higher level master cache apparatus performing the above-described step S311 of FIG. 6 or step S403 of FIG. 7 (S513).

As such, when receiving the redirect message from the upper level master cache device, the master cache devices 101 to 103 extract and store content location information (information of the cache device that caches content) from the redirect message ( In operation S517, the redirection message is transmitted to the corresponding slave cache device, the lower level master cache device, or the terminal devices 301 and 302. That is, when the terminal devices 301 and 302 corresponding to the destination of the redirection message are connected to the master device, the master cache devices 101 to 109 directly transmit the received redirection messages to the corresponding terminal devices 301 and 302. When connected through another cache device, the terminal device 301 transmits the information to the slave cache device or the lower level cache device so that the terminal device 301 or 302 is delivered.

As described above, the master cache apparatuses 101 to 103 set to the master mode share content caching information of other cache apparatuses, and provide the contents requested by the terminal apparatuses 301 and 302 through this sharing.

Meanwhile, as shown in FIG. 9, the cache devices set to the slave mode, that is, the slave cache devices 104 to 109, first store information about one master cache device, which is an upper node thereof (S601). ).

In this state, a content request message may be received from any terminal device 301 or 302 (S603).

As such, when the content request message of the terminal device 301 or 302 is received, the slave cache devices 104 to 109 determine whether the cache is hit for the content requested in the content request message (S605).

As a result of the determination in step S605, if it is determined that the cache hit, the content stored in the storage unit 120 is extracted to generate a content response message, and the generated content response message is transmitted to the corresponding terminal device 301 or 302 (S607). . That is, when the terminal devices 301 and 302 are caching the requested content, the cached content is provided to the terminal devices 301 and 302 instead of the content providing server 302.

On the other hand, if the cache hit in step S605, other cache device or content providing server 200 to provide the requested content, the received content request message to the master cache device (101 ~ 103) set in step S601 It transmits (S609).

In addition, the slave cache devices 104 to 109 may receive a content response message of the content providing server 200 through the upper master cache devices 101 to 103 (S611). When the content response message of the content providing server 200 is received through the master cache apparatuses 101 to 103, the content data included in the content response message is extracted and stored in the storage 120 (S613). The response message is transmitted to the terminal devices 301 and 302 which are the original destinations (S615). Through this, if the slave cache devices 104 to 109 are requested again for the same content, the slave cache devices 104 to 109 may directly service the stored content without having to request the content providing server 200.

In addition, the slave cache devices 104 to 109 may receive a redirect message for changing a content request position through the upper master cache devices 101 to 103 (S617). The slave cache devices 104 to 109 that have received the redirection message transmit the received redirection message to the terminal devices 301 and 302 as they are, so that the terminal devices 301 and 302 transfer the contents to the location changed in the redirection message. Request again to receive (S619).

The content transmission service method according to the present invention can be implemented in a form of software readable by various computer means and recorded in a computer-readable recording medium. Here, the recording medium may include program commands, data files, data structures, and the like, alone or in combination. Program instructions to be recorded on a recording medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. For example, the recording medium may be an optical recording medium such as a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, a compact disk read only memory (CD-ROM), a digital video disk (DVD) Includes a hardware device that is specially configured to store and execute program instructions such as a magneto-optical medium such as a floppy disk and a ROM, a random access memory (RAM), a flash memory, do. Examples of program instructions may include machine language code such as those generated by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like. Such hardware devices may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be apparent to those skilled in the art. Furthermore, although specific terms are used in this specification and the drawings, they are used in a generic sense only to facilitate the description of the invention and to facilitate understanding of the invention, and are not intended to limit the scope of the invention.

The present invention is applied to a content delivery service, and a plurality of cache devices distributed in a network are hierarchically divided and connected in a tree structure, and cache devices can share information about cached content with each other. Even if the device does not cache the content requested, the content can be provided through another cache device that is caching the content. As a result, the storage space of the cache devices can be used more efficiently. There is an excellent effect of further distributing the traffic that is concentrated to the providing server, so there is potential industrial use.

100: cache device
101-103: master cache device
104 ~ 109: Slave Cache Device
200: content providing server
301 and 302: terminal device

Claims (19)

The master cache device,
Storing setting information for at least one of at least one slave cache device, a higher level master cache device, and a lower level master cache device;
Receiving a content request message from a lower node which is one of the at least one slave cache device and the lower level master cache device;
Determining whether a cache hit is requested for the requested content;
If not a cache hit, sending the content request message to a higher level master cache device;
And sending a redirect message to the lower node if the cache hit is changed to change the location of the content request to itself. The method of claim 1,
Receiving, by the master cache device, a content response message from a content providing server or a higher level master cache device;
Extracting and storing content location information indicating a cache device from which the content response message is to be cached; And
And transmitting the content response message to the lower node or the terminal device requesting the corresponding content. The method of claim 1,
Receiving, by the master cache device, a redirect message from a higher level master cache device;
Extracting and storing content location information indicating a cache device in which content is cached from the redirection message;
And transmitting the redirection message to the lower node or the corresponding terminal device. The method of claim 1,
If it is not a cache hit, checking whether a high level master cache device exists; And
And transmitting a content request message to a content providing server if a high level master cache device does not exist. The method of claim 1,
If not a cache hit, checking whether there is content location information for the requested content;
If the content location information exists, generating a redirect message for changing the location of the content request to the cache device corresponding to the content location information, and transmitting the lower node or the content to the requesting terminal device. Transport service method. 6. The method of claim 5,
Checking the number of requests for the corresponding content before transmitting the redirection message to the lower node or the terminal device;
Requesting content from a cache device corresponding to the content location information if the number of requests is greater than or equal to a reference value;
Receiving a content response message sent from the cache device in response to the request, extracting and caching content from the content response message; And
And transmitting the received content response message to the lower node or the terminal device. Slave cache device,
Storing setting information of the master cache device;
Receiving a content request message of the terminal device;
Determining whether the requested content is cache hit;
Extracting cached content to generate a content response message if the cache is hit, and transmitting the generated content response message to the terminal device; And
If not a cache hit, transmitting the content request message to the content providing server through the master cache device. 8. The method of claim 7,
Receiving, by the slave cache device, a content response message for the requested content through the master device;
Extracting and caching content from the content response message;
And transmitting the content response message to the terminal device. 8. The method of claim 7,
And when the slave cache device receives the redirection message from the master device, transmitting the redirection message to the terminal device. Grouping a plurality of cache devices distributed in a network into a plurality of groups;
Setting a master cache device and a slave cache device that is a subordinate node of the master cache device for each group;
Hierarchically dividing the plurality of master cache devices into a tree structure;
Transmitting the content request message of the terminal device and the corresponding content response message to the content providing server and the terminal device through one or more master cache devices connected in a tree structure;
Receiving a content response message, the master cache device storing content location information indicating a cache device to cache content extracted from the content response message; And
Determining, by the master cache device that has received the content request message, whether a cache hit is made for the requested content; And
And in the case of a cache hit, transmitting, by the master cache device, a redirect message for changing the content request location to itself to the terminal device. 11. The method of claim 10,
If not a cache hit, checking, by the master cache device, whether content location information corresponding to the requested content exists; And
And if the content location information is present, transmitting, by the master cache device to the terminal device, a redirection message for changing the content request location in response to the content location information. The method of claim 10, wherein the setting of the master cache device and a slave cache device that is a subordinate node of the master cache device comprises:
The plurality of cache devices belonging to each group may be configured to compare the cache performance information including at least one of cache capacity, hardware performance, and the number of service target terminal devices to set the master cache device and the slave cache device. Transport service method. A communication interface for transmitting and receiving data through a network;
A storage unit for storing one or more of cached content, cache connection information defining other cache devices connected in a tree structure, and content location information about content stored in other cache devices; And
Check whether it is in master mode or slave mode, and in the master mode, store information about one or more of one or more slave cache devices, a high level master cache device and a low level cache device connected in a tree structure as the cache connection information; If the terminal device determines whether or not the cache hit for the requested content, the cache hit, the control unit for transmitting a redirection message for changing the content request location to itself through the one or more slave cache device or the lower-level master cache device to the terminal device; Cache device comprising a. 14. The apparatus of claim 13, wherein the control unit
In the master mode, a content response message or a redirect message for changing a location of a content request message is received from the upper level master cache device or the content providing server and transmitted to the terminal device through the one or more slave cache devices or the lower level master cache device. And extracting content location information indicating a cache device to which content is cached from the content response message or the redirection message and storing the content location information in the storage unit. 14. The apparatus of claim 13, wherein the control unit
In the master mode, if it is not a cache hit, it is further checked whether content location information of the requested content exists in the storage unit. If the content location information exists, the content request location corresponds to the content location information. And a redirection message for changing the cache device to the corresponding terminal device through the one or more slave cache devices or the lower level master cache device. 14. The apparatus of claim 13, wherein the control unit
It is determined whether to cache the content according to one or more of the number of request of the content and the location of the terminal device that requested the content. And receiving the corresponding content from the cache device and transmitting the content to the one or more slave cache devices or the lower level master cache device. 14. The apparatus of claim 13, wherein the control unit
When receiving the content request message from the terminal device, at least one of whether the requested content is a cache hit and the presence of the content location information is determined, and if the cache hit, the cached content is transmitted to the terminal device, and the cache hit is However, if there is content location information, the cache device, characterized in that for transmitting a redirect message for changing the content request location to the cache device corresponding to the content location information to the terminal device. 14. The apparatus of claim 13, wherein the control unit
In the slave mode, the configuration information of the master cache device, which is an upper node, is stored as cache connection information, and when a content request message is received from the terminal device, it is determined whether a content cache hit is performed. And transmits the content request message to the master cache device if it is not a cache hit. The method of claim 18, wherein the control unit
In the slave mode, when a content response message of a content providing server is received through the master cache device, the content response message is transmitted to the terminal device and the content data is extracted from the content response message and stored in the storage unit. Cache device, characterized in that.

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