KR20030027485A - Method And Apparatus For Content Routing Of Content Level In The Content Delivery Network - Google Patents

Abstract

PURPOSE: A device for routing a content of a content level in a CDN(Content Delivery Network) and a device thereof are provided to select an optimum edge server as updating a content routing table in consideration of availability and load of edge servers as well as proximity of the edge servers and a web user, thereby supplying an efficient content to the web user. CONSTITUTION: A content router(1) receives a content request of a web user(6), updates a content routing table(3) by monitoring states of edge servers, and performs content routing to a selected edge server by selecting the optimum edge server. The content router(1) supplies a content requested by the web user(6), and transceives routing table information with other content router. Web servers(8) and web cash(7) periodically inform the content router(1) of information on load or at the request of the content router(1), and inform the content router(1) of content changes. A content distributor(13) distributes contents of an original server to the web cash(7), and distributes the contents to the web servers(8) by changing a URL of the contents, then transmits information on content distribution to the content router(1).

Description

Method and apparatus for routing content at the content level in a content delivery network {Method And Apparatus For Content Routing Of Content Level In The Content Delivery Network}

The present invention relates to routing of the content level for content requested by a web user in a content delivery network (CDN) environment of the Internet. More specifically, the edge server state, i.e., in selecting an optimal edge server, is selected. By considering the availability of the edge server, the load on the edge server, and the proximity between the edge server and the web user, the content routing table can be updated according to the state, and the optimal edge server can be selected to provide effective content to web users. A content routing device and method are provided.

In recent years, with the rapid growth of high-speed Internet subscribers, the explosive growth of the Internet user population, and the development of Internet technology, the reliability of web users and various service requirements in the Internet field and the quality of service (QoS) of web services provided through the Internet The environment for the Internet is changing, such as guarantees and monetization of content.

These environmental changes require the Internet to be diverse and require new Internet services that can provide content to a large number of subscribers reliably and guaranteeing QoS, and the network structure that can meet these needs is the CDN, Routing to ensure that services are served by the most optimal edge server for content is content level content routing.

In general, content routing methods in CDN include DNS-based content routing method using domain name service and content routing method using HTTP redirection.

First of all, DNS-based content routing provides only proximity between DNS and the edge server where the content is stored. Therefore, DNS-based content routing cannot provide proximity to web users and thus cannot guarantee desired QoS.

In addition, the content routing method using HTTP redirection has a disadvantage in that all user requests are concentrated in the HTTP Redirector, which increases the load on the HTTP Redirector and cannot handle non-HTTP traffic.

On the other hand, the DNS-based content routing scheme is a host-based content routing scheme rather than a content level scheme. If the content requested by the web user is not present at the edge server, the DNS-based content routing scheme must obtain the corresponding content from the raw server and provide a service. .

An object of the present invention is to provide a content routing device and method capable of providing effective content to a web user by selecting an optimal edge server while solving the conventional problems as described above.

1 is a block diagram showing a schematic configuration of a content routing method of content level for carrying out the present invention.

FIG. 2 is a block diagram illustrating an operation of a content router of a content level in FIG. 1 in detail.

3 is a block diagram showing in detail the operation of the state monitoring of the edge server in FIG.

Figure 4 is a block diagram showing in detail the operation of the web cache of the edge server in Figure 1;

FIG. 5 is a block diagram illustrating an operation process of a web server among edge servers in FIG. 1; FIG.

FIG. 6 is a detailed block diagram illustrating an operation of content change history notification of an edge server of FIG. 1. FIG.

FIG. 7 is a block diagram illustrating an operation of content distribution history notification of a content distributor in FIG. 1 in detail. FIG.

Content routing device for content routing for the content requested by the web user in the CDN environment of the Internet according to the present invention,

Content requested by the web user by accepting the web user's content request, monitoring the state of the edge server, updating the content routing table according to the monitoring result, selecting an optimal edge server, and performing content routing to the selected edge server At the same time to provide a content router for transmitting and receiving information about the content with another content router;

A web server and a web cache which periodically informs the content router of information on a load it is serving or at the request of the content router, and notifies the content router when there is a change of content stored in the content router; And

A content distributor that distributes the content of the original server to the web cache, changes the content URL to the web server, and delivers the information about the content distribution to the content router to enable content level content routing. Characterized in that it comprises a.

In addition, according to the content routing method for the content requested by the web user in the content delivery network (CDN) environment of the Internet,

Calculating web user information and URS by receiving a content request from the web user;

Examining the content routing table to determine whether the calculated URS exists;

If there is no URS value, checking the edge server load stored in the routing table according to the configuration of the web cache and the web server and performing content routing to the edge server having the least load; And

As a result of the determination, if there is a URS value, selecting a routing table as many as the number of values selected from the content routing table, selecting an optimal edge server, and performing content routing to the selected edge server. do.

As will be described later, according to the content routing device and method according to the present invention, a function that allows a content router to find an optimal edge server according to the state of the edge server that stores the content to the web user, the content router to determine the state of the edge server that stores the content The ability to monitor, the content router to update the content routing table according to the state of the edge server where the content is stored, to configure the environment between content routers at the content level content router, and to configure the environment of the edge server where the content will be stored. The ability to configure the content distributor's environment for edge servers and content routers where content will be stored, to inform content routers of changes in content at the edge server, and to inform content routers of the load handled by the edge server. Feature, content routers stored on Edge Servers Simplify edge server selection by inspecting content, organizing an edge server family by grouping multiple edge servers where content will be stored, and prioritizing edge servers in selecting the optimal edge server for content. And a function of notifying the content router of the corresponding content when the content distributor distributes the content to the edge server.

In addition, the content router performing content routing at the content level in the content routing device according to the present invention checks whether the edge server can serve, and whether the content is stored in the edge server for the content requested by the web user. Detect information about the load history of the edge server, receive content change history of the edge server, receive content change history from the content distributor, detect edge server status, change edge server content, and load the edge server. It maintains the content routing table according to the user and selects the optimal edge server stored in the content routing table according to the web user.

On the other hand, when the server receives a server load request from the content router, the edge server measures the load it is serving and informs the content router. If the server receives the server's status detection message from the content router, the edge server receives a normal state or failure status message. Notify the content router, notify the content router of the change history if the content changes, detect the 'freshness' of the content request from the content router, and receive the content router from the content router. When there is no content for one content request, the content server retrieves the content from the source server, informs the content router about the content from the source server, and serves the web user for the content request received from the content router.

The content distributor informs the content router of details of pushing content to the edge server, and performs a content routing function of the configured content level. The function of measuring the load of the edge server is a general technique, which can be known through CPU usage, and can be implemented in other software.

On the other hand, the above-mentioned functions of the content router and the edge server are basically performed when an event occurs. For example, when content is distributed in a content distributor, an event occurs only at the corresponding edge server. In addition, the content router performs a function of periodically transmitting or receiving information on content corresponding to a request of a web user.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention by way of example only. Advantages and features of the present invention will be more clearly understood through the following detailed description, and detailed descriptions of well-known techniques not directly related to the gist of the present invention will be omitted.

Referring to FIG. 1, a content routing method of a content level to which the present invention is applied is illustrated.

First, the web user 6 makes a request to the content router 1 through the Internet for the content to be requested. The content router 1 checks its routing table 3 for the requested content and routes it to the web cache 7 or the web server 8 that is closest to the web user 6. The web cache 7 or web server 8 services its content 10, 9 to the web user 6, respectively. On the other hand, the content 10 of the web cache 7 is stored in the same form as the content 12 of the raw server 11, the content 9 of the web server 8 is the content ( 12, the Uniform Resource Locator (URL) is changed and stored.

The content distributor 13 distributes the content 12 of the raw server 11 to the web cache 7 in the same form through the Internet, or changes the URL of the content to the web server 8. In this case, the information about the content distribution 14 is transmitted to the content router 1 for the content 12 to be distributed.

The web server 8 or the web cache 7 informs the content router 1 periodically or when the content router 1 requests the information 4 on its current service load. When the stored content 10, 9 is deleted, added, or changed to new content, the content router 1 is informed of the information 4.

The content router 1 periodically monitors the state of the web server 8 or the web cache 7 connected thereto to adjust the routing table 3 of the content router 1, and the other content routers. Periodically exchanges the contents of the routing table stored in its own content router.

Meanwhile, in using the routing table to select the edge server, in order to monitor the state of the network in the routing table, various tools such as ping or traceroute may be used.

2, there is shown a flow chart for explaining the operation of the content router in the content routing method according to the present invention.

When the content router 1 receives the content request from the web user (201), examines the data for the web user (202), calculates the URS value through the hash function (203), and the URS in the content routing table. The value is examined (204) and a determination is made (205) if a URS value exists. If it is determined that there is no URS value, the load of the stored edge server is checked (208) through the web cache configuration (206) and the web server configuration (207), and the content is routed to the least loaded edge server (209). If there is a URS value in the content router 1 as a result of the determination, the routing table is selected (213) by the number of values selected from the content routing table (213) and the optimal edge server is selected (214). To perform content routing 215 to the selected edge server.

In the content router 1, the content routing table is provided through edge server load detection (314 and 414), edge server status monitoring (100), edge server content change reception (319 and 419), and content change history reception from the content distributor (600). Change 211 and reflect it to the content routing table (212).

On the other hand, the content routing table is operated by maintaining proximity with a web user or by determining a priority for an optimal server among a web cache or a web server adjacent to the web user.

In addition, the content routing table may be managed through a method of reducing the size of the routing table by grouping web users by a network address.

Referring to FIG. 3, a flowchart illustrating an operation process of the edge server state monitoring performed by the content router is shown. According to a preferred embodiment of the present invention, the edge server state is checked based on whether the edge server is in a normal state or a down state or the load state of the edge server.

The edge server status monitoring 100 receives user input 101 for the number of non-response down of the edge server, receives user input 102 for the number of consecutive non-response of the edge server, and receives the edge server status request message. To transmit 103.

After determining 106 whether or not the edge server responds, if the response message comes from the edge server, the edge server state is set to normal 105, and the number of consecutive edge server non-responses to 104 is reset 104. Proceed to step 103 of sending an edge server status request message. If the edge server does not receive a response as a result of the determination, the number of consecutive non-response Bs (B) is increased (107), and the number of non-responses (108) is compared 108 to the number of consecutive non-responses (B). If (B) is large, the edge server state is set to down 110, and then the content routing table is changed (109). If the number of non-responses is less than or equal to (B), the edge server state request message transmission step 103 is performed.

An operation process of the web cache 7 will be described with reference to FIG. 4.

The web cache 7 receives the message from the content router 301 and determines 302 the message type.

As a result of the determination, when the message type is the cache status monitoring message 303, the cache status is checked 304 and the cache status is normal 305, and when the cache status is normal, the cache status normal message is transmitted ( 306) and transmits a cache failure message 307 when the cache status is abnormal.

As a result of the determination, when the message type is a web request message 308 from the content router, the system checks whether there is content corresponding to the web cache (309), and then determines whether the content exists (310). If the 'freshness' is checked and 'fresh', the content is serviced (313). If the content is not 'fresh' or the content does not exist, the content is fetched from the raw server. (pull) 317, changes the content of the cache (318), and then notifies the content router of the cache state change history (319) and services the content (313).

On the other hand, in the case where the determination result is the cache load request message 314, the load state of the cache is measured 315 to respond to the cache load state (316).

Referring to FIG. 5, a flowchart illustrating an operation process of the web server 8 is shown.

The web server 8 receives the message from the content router (401) and determines (402) the message type.

If the determination result message type is the server status monitoring message 403, the server status is checked (404), the server status is normal (405), and if the server status is normal, the server status normal message is sent (406). If the server status is abnormal, a server status failure 407 message is transmitted.

In the case where the determination result message type is a web request message 408 from the content router, it is determined whether there is content corresponding to the web server (409), and if the content exists (410), the content is present. If the 'freshness' of the content is checked (411) and 'fresh' the content is served (413), if the content is not 'fresh' or if the content does not exist, pull the content from the raw server (pull) In step 417, the server changes the content of the server (418), then notifies the content router of the server state change history (419), and then services the content (413).

On the other hand, if the message type is the server load request message 414 as a result of the determination, the server load status is measured 415 and the server load status is responded 416.

Next, an operation process of the content change notification of the edge server will be described with reference to FIG. 6.

The edge server content change notification 500 of the edge server 7, 8 first receives content 501 from the content distributor, stores the content 10, and then checks whether the content was previously stored 503. do. If the result of the investigation is not the existing content (504), the content router is notified of the change history of the edge server (505).

Referring to Figure 7 will be described the operation of the content change history notification of the content distributor (13).

The content distributor content change history notification 600 of the content distributor 13 determines 602 after the content distributor receives the content distribution request (601), which server stores the content. As a result of the determination, in the case of the web cache 603, the content and details are pushed to the web cache, and the content router is notified of the content change history (605). After changing the details (607) and PUSH (608) the content and the history to the web server, the content change history is notified to the content router (605).

As we have seen, using the content-level content routing technology according to the present invention, economically, Web users can select the optimal edge server to reduce the traffic of the Internet backbone in configuring the CDN. It has the effect of reducing the number of users, and by selecting the optimal edge server, it can minimize the delay between web users and the edge server that can occur on the Internet, and can build a reliable Internet. have.

In addition, in terms of expected effects, it is possible to configure an optimal CDN structure to provide a CDN service, and to create a new service by enabling high bandwidth streaming.

The description so far has described the principles and features of the present invention by taking specific embodiments of the present invention for the purpose of understanding the present invention, but the scope of the present invention is not limited by these embodiments. Those skilled in the art can make various changes and modifications without departing from the scope and spirit of the appended claims.

Claims (12)

In the content routing device for content routing for content requested by a web user in a content delivery network (CDN) environment of the Internet, Content requested by the web user by accepting the web user's content request, monitoring the state of the edge server, updating the content routing table according to the monitoring result, selecting an optimal edge server, and performing content routing to the selected edge server At the same time to provide a content router, the content router to exchange the routing table information with another content router; A web server and a web cache which notifies the content router periodically or upon request of the content router, and informs the content router of changes in the content stored in the content router; And And a content distributor for distributing the content of the original server to the web cache, changing the URL of the content to the web server, and delivering the content distribution information to the content router. Rooting device. The method of claim 1, The content router is a content routing device, characterized in that to find the content of the content stored in its web server or web cache using a hash (hash) function. In the content routing method for content routing for content requested by a web user in a content delivery network (CDN) environment of the Internet, Calculating web user information and URS by receiving a content request from the web user; Examining the content routing table to determine whether the calculated URS exists; If there is no URS value, checking the edge server load stored in the routing table according to the configuration of the web cache and the web server and performing content routing to the edge server having the least load; And As a result of the determination, if there is a URS value, selecting a routing table as many as the number of values selected from the content routing table, selecting an optimal edge server, and performing content routing to the selected edge server. How to route content. The method of claim 3, wherein In the operation of the content routing table, content routing method characterized in that to maintain the proximity (proximity) with the web user. The method of claim 3, wherein In the operation of the content routing table, the content routing method, characterized in that for determining the priority of the optimum server among the web cache or web server adjacent to the web user. The method of claim 3, wherein In maintaining the content routing table, grouping web users by a network address to reduce the size of the routing table. The method of claim 3, wherein Computing the URS is a content routing method, characterized in that performed using a hash (hash) function. The method of claim 3, wherein And modifying the content routing table through load detection of the edge server, monitoring of the edge server status, receiving the change history of the edge server content, and receiving content change history from the content distributor. Way. The method of claim 8, The method for monitoring the state of the edge server Receiving user input for an edge server down non-response number (A) and a continuous edge server non-response number (B), respectively, and sending a status request message of the edge server to an edge server; If it is determined whether the edge server responds, if the response message comes from the edge server, set the edge server to normal, reset the continuous edge server non-response number (B) to "0", and then request the status of the edge server. Moving to a transmission step; As a result of the determination of the response, if no response message is received from the edge server, the number of consecutive edge server non-responses B is increased, and then the number of edge server no responses B and the number of no edge server down responses A are compared. Doing; As a result of the comparison, if the number of non-responses (B) is large, setting the edge server state to 'down', changing the content routing table, and performing a status request message transmission step of the edge server; And And if the number of non-responses (B) is less than or equal to the comparison result, performing the step of transmitting the status request message of the edge server. The method of claim 8, The configuration of the web server or web cache is: Determine a message type after receiving a message from the content router; If the result of the determination is a server or cache state monitoring message, examine the server or cache state and transmit a server state or cache state normal or bad message; As a result of the determination, in the case of the web request message from the content router, the content corresponding to the web cache is examined. If it is not 'fresh' or if the content does not exist, the content is fetched from the raw server, the content of the web cache is changed, and the content router is notified of the change; And If the server or the cache load request message as a result of the determination, the content routing method comprising the step of measuring the server or cache load status and sending a response message. The method of claim 8, The content change notification of the edge server is: Receiving and storing content from the content distributor; Checking whether the content is stored previously; And And informing the content router of the change of the edge server if the content is not the existing content. The method of claim 8, The content change history notification in the content distributor is: Determining a content storage server after receiving the content distribution request; If the result is a web cache, pushing the content and the details to the web cache and then notifying the content router of the content change details; And And in the case of the web server, after changing the content details, pushing the content details and details to the web server and notifying the content router.