KR20000064071A - Web contents transmission system and method - Google Patents

Abstract

PURPOSE: A web contents transmission system and a transmission control method are provided to transmit the web contents in high speed by eliminating the bottle neck state in a web server and the network. CONSTITUTION: A client DNS(Domain Name Server)(104), if a domain name interpretation inquiry for a specific web server is requested from a client(102), searches a mapping table, determines an intelligent DNS(106) in charge of the domain name interpretation the specific web server and transfers access information for the determined DNS to the client(102). The intelligent DNS(106), if a domain name interpretation inquiry for a specific web server is requested from a client(102), selects the nearest web cache cluster among a plurality of web cache clusters(110/1,110/2) to the client and transfers the IP address of the selected web cache cluster to the client(102). The web cache clusters(110/1,110/2) access a web server(112) through an internet(108) and stores web files in the web server(112).

Description

Web content delivery system and transmission control method {WEB CONTENTS TRANSMISSION SYSTEM AND METHOD}

The present invention relates to a technique for controlling the delivery of web content on the World Wide Web, and more particularly, suitable for eliminating bottlenecks in web servers and networks when delivering web content on the World Wide Web. It relates to a system and a transmission control method thereof.

In recent years, the exponential growth in the number of users on the Internet has resulted in immense loads on the traffic paths (network lines) between Internet servers, especially web servers and clients, and these overloads cause server bottlenecks and network bottlenecks. It is acting as a major factor that significantly reduces the quality of service to clients.

In a typical conventional client-server system, as shown in FIG. 5 as an example, a number of clients 502 access the web server 506 via the Internet 504 to retrieve desired information (ie, data data). It has a form of receiving service. In these systems, a web server installed on the network handles the services for all clients directly.

That is, when the client 502 requests a web document from the web server 506 together with a uniform resource locator (URL) (transmission of an information request packet), the web server 506 stores the web document specified by the URL in its database. After constructing the information packet from the service and then configured to service the client 502 the configured information packet via the Internet (504).

However, the manner in which the web server 506 processes all client requests in this way has a problem that the quality of service is drastically deteriorated due to a bottleneck in the web server and the network due to the rapid increase of Internet users. Therefore, in order to eliminate the bottlenecks, we can consider using a high-performance server or a cluster of multiple servers and leasing a high-bandwidth network. However, these methods require high installation and management costs. Rather, the limited bandwidth of a single network circuit is inherently limited in eliminating bottlenecks in the network.

Therefore, as one of the methods for solving the bottleneck as described above, methods for supporting a high-speed web service by minimizing the bottleneck using a web cache have been proposed and used.

6 is a schematic diagram of a web content delivery system using a conventional web cache, and includes a client 602, a web cache 604, and a web server 608.

Referring to FIG. 6, when the client 602 requests a web document with a URL, the web cache 604 intercepts and searches whether the web document designated by the URL exists in its database, and the search result itself If the requested web document exists in the database, the web cache 604 retrieves it and sends it to the client 602.

Unlike the above, if it is determined that the requested web document is not in the database of the web cache 604 or is not the latest document, the web cache 604 sends the web document to the web server 608 via the Internet 606. Request and receive, and transmit the received web document to client 602.

On the other hand, it is very important for a web server to provide a high quality service to all clients evenly in performing Internet networking. However, a conventional method using a web cache does not provide excellent services to all clients. In other words, only a client with a web cache receives a relatively good service, but a client without a web cache has a relatively low quality service.

Thus, the conventional method of using the web cache is a very passive way from the point of view of the web server operator to expect the web cache to be installed in every client's network.

In addition, conventional methods using a web cache do not provide a high cache hit ratio because the web cache must store documents of all web servers. That is, from the point of view of the web server operator, all web documents cannot use the functions of the web cache because the documents of their web server may be removed from the web cache by the documents of other web servers. Cache hit ratios in such systems are generally known to be on the order of 40-50%.

Accordingly, the present invention is to solve the above-described problems of the prior art, by installing a plurality of web cache clusters locally distributed, and through the method of connecting the client to the adjacent web cache cluster using intelligent DNS or redirector It is an object of the present invention to provide a web content delivery system and a transmission control method capable of providing a high speed web document service by eliminating bottlenecks in a web server and a network.

In accordance with one aspect of the present invention for achieving the above object, there is provided a web content delivery system for serving a plurality of clients with a web document stored in a web server, wherein the domain name is resolved from an arbitrary client to a specific web server. A customer DNS that searches a mapping table to determine an intelligent DNS that is in charge of domain name resolution of the specific web server, and delivers the access information for the determined intelligent DNS to the service request client; When the domain name resolution query of the specific web server comes from the service request client, a web cache cluster closest to the service request client is selected from a plurality of web cache clusters installed in each network, and the IP address of the selected neighbor web cache cluster is selected. Intelligent DNS for delivering to the service request client; And a plurality of web cache clusters configured to transmit an information packet to the service request client by constructing an information packet from the service request client when the service request for the web document comes from the service request client.

In accordance with one aspect of another aspect of the present invention, there is provided a web content transmission control method for serving a web document stored in a web server to a plurality of clients, wherein the domain name for a specific web server from any client. Searching for a mapping table to determine an intelligent DNS that is in charge of resolving the domain name of the specific web server, and transmitting access information about the determined intelligent DNS to the service request client; Querying the determined intelligent DNS for domain name resolution of the specific web server; In response to the domain name resolution query, selecting a proximity web cache cluster closest to the corresponding client requesting a service among a plurality of web cache clusters installed in each network; Delivering the IP address of the selected proximity web cache cluster to the corresponding client; And receiving a service of a web document from the proximity web cache cluster by using the IP address.

In accordance with another aspect of one aspect for achieving the above object, there is provided a web content delivery system for serving a web document stored in a web server to a plurality of clients, wherein the domain name is resolved for a specific web server from any client. A customer DNS that searches a mapping table to determine a redirector when the query comes, and delivers connection information for the determined redirector to the service requesting client; When the specific web document request is received from the service request client, a web cache cluster closest to the service request client is selected among a plurality of web cache clusters installed in each network, and the URL of the selected proximity web cache cluster is determined by the service request client. At least one redirector for transmitting to the at least one redirector; And a plurality of web cache clusters configured to transmit an information packet to the service request client by constructing an information packet from the service request client when the service request for the web document comes from the service request client.

In accordance with another aspect of another aspect of the present invention, there is provided a web content transmission control method for serving a web document stored in a web server to a plurality of clients, wherein the domain name for a specific web server from any client is provided. Searching for a mapping table to determine a redirector when the analysis query arrives, and transmitting access information about the determined redirector to the service request client; Requesting the determined redirector for the particular web document; In response to the specific web document request, requesting service selection information from a plurality of web cache clusters installed in each network by a redirector; Selecting a proximity web cache cluster closest to a corresponding client requesting a service among the plurality of web cache clusters based on the service selection information received from each web cache cluster; Delivering a URL of the selected proximity web cache cluster to the corresponding client; And providing a service of a web document from the proximity web cache cluster by using the URL.

1 is a schematic diagram of a web content delivery system according to an embodiment of the present invention;

2 is a flowchart illustrating a process of controlling the transmission of web content according to an embodiment of the present invention;

3 is a schematic diagram of a web content delivery system according to another embodiment of the present invention;

4 is a flowchart illustrating a process of controlling transmission of web content according to another embodiment of the present invention;

5 is a system schematic diagram showing a connection between a typical client and a web server;

6 is a schematic diagram of a system for transmitting a web content using a conventional web cache.

<Description of the code | symbol about the principal part of drawing>

102, 302: Client 104, 304: Customer DNS

106: Intelligent DNS 108, 308: Internet

110/1, 110/2, 310/1-310/4: web cache cluster

112, 312: web server 306: redirector

The above and other objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the core technical aspect of the present invention is to distribute a plurality of web cache clusters locally in a network, to store the documents of the web server in a web cache cluster located closer to the client, and the arbitrary client stores the web document. The purpose of the present invention is to eliminate the bottlenecks on the web server and the network through such technical means by providing a web document to the requesting client by an intelligent web cache cluster connected by intelligent DNS or redirector when requesting service. Can easily be achieved.

1 is a schematic diagram of a web content delivery system according to an embodiment of the present invention. The client 102, the customer DNS 104, the intelligent DNS 106, the web cache clusters 110/1, 110/2, and the web are illustrated in FIG. Server 112, and the client 102, web cache clusters 110/1, 110/2, and web cache clusters 110/1, 110/2, and web server 112 connect to the Internet 108. Are interconnected through.

Referring to FIG. 1, a customer DNS (Domain Name Server) 104 resolves a URL when a resolution query for a domain name (eg, an IP address request of www.server.com) comes from the client 102 with the URL. After searching the mapping table, the intelligent DNS that provides the service for the IP address requested by the client is determined, and a response message for inducing a connection to the intelligent DNS determined by the service is generated and delivered to the client 102. do. To this end, an NS record is stored in the mapping table in the customer DNS 104 to direct access to the intelligent DNS corresponding to each domain name.

Next, the intelligent DNS 106 receives a resolution query for the domain name from the client 102, e.g., a request for an IP address of www.server.com, and the rule or network predefined by the administrator. The web cache cluster determined to be closest to the client 102 requesting the service is considered in consideration of the current traffic situation, and the IP address of the determined web cache cluster (for example, 110/1) is transmitted to the client 102. To pass.

In addition, a web cache cluster (eg, 110/1) connects to the web server 112 via the Internet 108 and stores web documents of the web server 112, thereby storing the web from the client 102. When a service request for a document comes (ie, an information request packet is received), the document is found and sent to the service request client 102. Such a web cache cluster is composed of a plurality of web cache servers, thereby providing high quality services with high speed processing, high response time, and high availability to each client requesting service.

That is, the web cache cluster 110/1 searches whether the web document designated by the URL is stored in its database. If the search results indicate that the web document is requested from the client 102 in its database, The web server retrieves the stored web document, constructs an information packet, and transmits it to the client 102 who requested the service through the Internet 108.

On the other hand, if there is no requested web document in the database of the web cache cluster 110/1 or the document is not the latest document, the web cache cluster 110/1 transmits to the web server 112 through the Internet 108. The web document is requested and received, and the web document is stored (or updated) in its own database and then transmitted to the service request client 102.

On the other hand, each web cache cluster, in contrast to the passive caching method described above, which caches the content accessed by the first client to a web cache cluster in a specific web document information of a web server, is an active caching method or a mirroring method. Can cache content.

That is, the web cache cluster receives a definition and update rule for what content is cached from each content provider (ie, a web server), and an active caching method for caching the content determined according to the definition and the rule in advance in the web cache cluster. To any client through a mirroring scheme that caches the web cache cluster by providing content to any client, or by copying some or all of the web server's content in advance according to a schedule rule received from the content provider (web server). The content may be provided, and in the case of mirroring, the content of the web cache cluster is updated only when the content provider requests it.

Accordingly, in the present invention, the passive caching method, the active caching method, or the mirroring method may be appropriately selected and used according to need or use, and in some cases, the caching method may be changed according to each content content through modification thereof. It can also be used as a complex caching method.

In FIG. 1, the web cache cluster 110/1 and the web cache cluster 110/2 are clusters installed in different networks. In this embodiment, only two web cache clusters are illustrated.

Finally, when there is a request for information (i.e., a web document request) from any web cache cluster, the web server 112 retrieves the document and provides the information to the requesting web cache cluster, or according to established and updated rules. By providing some or all of the content to the web cache cluster or providing content for renewal, the customer of such a web server 112 is, for example, a web server operating company, such as portal sites, e-commerce sites, search sites, online newspapers. The site is a major customer.

In other words, the web content delivery system according to the present invention is installed in a plurality of web cache clusters distributed locally in a network, and intelligent according to the predefined rules or the current network traffic conditions when any client requests a web document service Because the DNS cache that is selected and connected by nearby web caches provides web documents (content) to clients who request service, bottlenecks in web servers and networks can be reliably eliminated, providing high speed for each client. It can provide a web document service.

Next, a process of controlling the transmission of the web content according to a rule defined in advance or the current traffic state of the network using the web content delivery system according to the present embodiment having the above-described configuration will be described.

2 is a flowchart illustrating a process of controlling the transmission of web content according to an embodiment of the present invention.

Referring to FIG. 2, when the client 102 queries the customer DNS 104 for domain name resolution (IP address request) (step 202), the customer DNS 104 resolves the domain name and retrieves the mapping table. The intelligent DNS (eg, 106) that provides a service for the IP address requested by the client is determined, and a response message for inducing a connection to the intelligent DNS for which the service is determined is generated and forwarded to the client 102 (step 204). ). At this time, in the mapping table in the customer DNS 104, NS records for inducing access to the intelligent DNS corresponding to each IP address are stored in advance.

Next, when the client 102 receives a response message from the customer DNS 104, the client 102 analyzes the response message to determine the intelligent DNS, for example, the intelligent DNS 106, to which the client should query the resolution of the domain name. The intelligent DNS 106 is queried for resolution of the domain name of the web server to which it is to connect (step 206).

Subsequently, when the intelligent DNS 106 receives the query for resolving the domain name from the client 102, the intelligent DNS 106 refers to the client 102 that requested the service by referring to a rule predefined by the administrator or the current traffic state of the network. After determining the determined web cache cluster, for example, determining the web cache cluster 110/1, the IP address of the determined web cache cluster 110/1 is transmitted to the client 102 (step 208).

Accordingly, the client 102 connects to the web cache cluster 110/1 using the IP address designated by the intelligent DNS 106 and requests the service of the web document (content) that it needs (step 210). .

Next, the web cache cluster 110/1 checks whether the client 102 requesting the service is stored in its database or if it is up-to-date data (step 212), where If it is determined that the web document requested for the service is stored as the latest data in its database (i.e., cache heating), the requested web document is fetched to construct an information packet (step 214), and then the Internet Information packet is transmitted to the corresponding client 102 through 108 (step 220).

As a result of the search in step 212, if it is determined that the web document requesting the service is not stored in its database or is not the latest document, the web cache cluster 110/1 is connected to the Internet 108 through the Internet 108. The client accesses the web server 112 and transmits a request for a web document requesting a service, that is, an information request packet to the server 112 (step 216).

Therefore, the web server 112 transmits the requested web document to the web cache cluster 110/1, and the web cache cluster 110/1 transfers the web document received from the web server 112 to its database. After storing (step 218), it is sent to the client 102 who requested the service (step 220).

Meanwhile, in the above-described embodiment, the content is provided to an arbitrary client through a passive method of caching the content accessed by the first client to a web cache cluster to specific web document information of the web server. It is not necessarily limited to this.

That is, in the scheme according to the present embodiment, each web cache cluster receives a definition and update rule for what content is to be cached from each content provider (that is, a web server), and the contents determined according to the definition and the rule are pre-stored in the corresponding web. Proactive caching that caches from the server, providing content to any client who requested the content service, or caching mirroring to copy some or all of the content of the web server in advance according to a schedule rule received from the content provider (web server). In this manner, the content may be provided to any client who requested the content service. In this case, in the mirroring method, the content of the web cache cluster is updated only when the content provider requests.

Accordingly, in the method according to the present embodiment, a passive caching method, an active caching method, or a mirroring method may be appropriately selected and used according to a need or use, and in some cases, a caching method may be used according to each content content through modification thereof. It can also be used as a complex caching method.

Therefore, in the present invention, a plurality of web cache clusters are distributed locally, most requests are handled by adjacent web cache clusters, and each web cache cluster caches only web documents of subscribed customers (that is, clients). It may have a cache hit ratio close to 100%.

In addition, in the present invention, since each web cache cluster is connected to a different network line, it is possible to increase service bandwidth by increasing the number of web cache clusters, and intelligent DNS assigns the fastest web cache cluster to a client requesting a service. By minimizing the delay time caused by the network line, high quality service can be provided.

3 is a schematic diagram of a web content delivery system according to another exemplary embodiment of the present invention, wherein a client 302, a customer DNS 304, at least one redirector 306, and a plurality of web cache clusters 310/1-310 / are illustrated in FIG. 4) and web server 312, wherein client 302 and web cache clusters 310/1-310/4 and web cache clusters 310/1-310/4 and web server 312 are connected to the Internet. 308 are interconnected.

Referring to FIG. 3, the biggest technical feature and difference is that the web content delivery system according to the present embodiment employs the redirector 306 instead of the intelligent DNS 106 employed in the above-described delivery system. With the exception of these differences, the configuration and the respective functions of the constituent members are substantially the same as or similar to those in the above-described embodiments.

In addition, in FIG. 3, only one redirector 306 is illustrated, but is not necessarily limited to one, and a plurality of redirectors 306 may be installed depending on the number of web cache clusters considering the size of a network. In this case, an NS record for inducing a connection to the redirector corresponding to each domain name is stored in the mapping table in the customer DNS 304.

Therefore, in order to improve understanding through simplification of description and to avoid unnecessary duplication, in this embodiment, the service provided by the redirector 306 (that is, the URL information service of the web cache cluster closest to the client requesting the content service) is used. Only the characteristic parts centered on the description will be described.

First, when the client 302 queries for resolution of the domain name with the URL (for example, requesting an IP address of www.server.com), the customer DNS 304 interprets the received URL and writes the result to the resolution. As a result, the mapping table is searched to determine a redirector (eg, 306 of FIG. 3) that provides a service for the URL requested by the client 302, and a response message for inducing a connection to the redirector 306 where the service is determined is provided. Create and deliver to client 302.

Subsequently, when the web document request comes from the client 302, the redirector 306 searches the mapping table according to a rule predefined by the administrator to register each web cache cluster 310/1-310/4 registered with it. A query to the web cache cluster 310/1-310, requesting distance information (ie, the distance between the web cache cluster and the client 302) and the current traffic state information of the network, in response to the request. The web cache cluster (for example, 310/4 of FIG. 3) closest to the client 302 who requested the service by referring to the distance information received from the network information and the current traffic state information of the network. The URL of the cluster (eg 310/4) is passed to the client 302.

Accordingly, the client 302 requesting the content service may be provided with the necessary content by accessing the web cache cluster 310/4 using the URL received from the redirector 306.

On the other hand, each of the web cache clusters employed in the web content delivery system according to the present embodiment, like the web cache clusters in the above-described embodiment, according to the need or use, a passive method, an active method, a mirroring method or a complex method This allows you to cache content from your web server.

Accordingly, the web content delivery system according to the present embodiment can reliably eliminate bottlenecks in the web server and the network, as in the above-described embodiment, thereby providing a high-speed web document service to each client. .

Next, a process of controlling the transmission of the web content according to a rule defined in advance or the current traffic state of the network using the web content delivery system according to the present embodiment having the above-described configuration will be described.

4 is a flowchart illustrating a process of controlling transmission of web content according to another embodiment of the present invention.

4, when the client 102 queries the customer DNS 304 for the domain name resolution (IP address request) (step 402), the customer DNS 304 resolves the domain name and retrieves the mapping table. The client determines a redirector (eg, 306) providing a service for the requested URL, and generates and sends a response message to the client 302 to induce a connection to the determined redirector 306 (step 404). ). At this time, in the mapping table in the customer DNS 304, an NS record for inducing to connect to a redirector corresponding to each IP address is stored in advance.

Next, when the client 302 receives a response message from the customer DNS 304, the client 302 analyzes the response message and queries the redirector 306 for the URL of the web server to which the client wants to connect (step 406).

Subsequently, upon receiving the URL query from the client 302, in response, the redirector 306 retrieves the mapping table according to a predefined rule and sends it to each web cache cluster 310/1-310/4 registered with it. A query is sent, i.e. requesting distance information between the web cache cluster and the client 302 and current traffic state information of the network (step 408).

In response, each web cache cluster 310/1-310/4 collects distance information between the client 392 and itself and current traffic state information of the network and sends it to the redirector 306 via the Internet 308. (Step 410).

Next, the redirector refers to the web cache cluster closest to the client 302 who requested the service by referring to the distance information received from each web cache cluster 310/1 to 310/4 and the current traffic state information of the network. 3 and 310/4 of FIG. 3, the URL of the determined web cache cluster (for example, 310/4) is transmitted to the corresponding client 302 (step 412).

Accordingly, the client 302 connects to the web cache cluster 310/4 using the URL specified by the redirector 306 and requests the service of the web document (content) that it needs (step 414).

Next, the web cache cluster 310/4 checks whether the client 302 requesting the service is stored in its database or if it is up-to-date (step 416). If it is determined that the web document requested for the service is stored as the latest data in its database (ie, cache heating), the requested web document is fetched to construct an information packet (step 418), and then the Internet ( 308 transmits the information packet to the client 302 (step 424).

If the search result in step 416 determines that the web document requesting the service is not stored in its database or is not up-to-date, the web cache cluster 310/4 is connected via the Internet 308. The user accesses the web server 312 and requests a web document requesting a service, that is, transmits an information request packet to the web server 312 (step 420).

Therefore, the web server 312 transmits the requested web document to the web cache cluster 310/4, and the web cache cluster 310/4 sends the web document received from the web server 312 to its own database. After saving (step 422), the service is sent to the client 302 who requested the service (step 424).

Meanwhile, in the above-described embodiment, the content is provided to an arbitrary client through a passive method of caching the content accessed by the first client to a web cache cluster to specific web document information of the web server. It is not necessarily limited to this.

That is, in the method according to the present embodiment, as in the above-described embodiment, each web cache cluster is configured to cache content from the corresponding web server through a passive method, an active method, a mirroring method, or a complex method according to a need or a purpose. Can be.

Accordingly, the web content delivery system according to the present embodiment can reliably eliminate bottlenecks in the web server and the network, as in the above-described embodiment, thereby providing a high-speed web document service to each client. .

As described above, according to the present invention, a plurality of web cache clusters are installed at the end of a network, and when an arbitrary client requests a web document service, an intelligent DNS or redirector is applied according to predefined rules or current traffic state of the network. By selecting the web cache cluster at the closest distance and allowing the client to receive web document services from the selected web cache cluster at the closest distance, bottlenecks in web servers and networks can be reliably eliminated. It is possible to provide a high speed web document service to each client on the web.

Claims (20)

In a web content delivery system for serving a web document stored in a web server to a plurality of clients, When a domain name resolution query for a specific web server is received from an arbitrary client, the mapping table is searched to determine an intelligent DNS that is in charge of domain name resolution of the specific web server, and the access information for the determined intelligent DNS is requested for the service. Customer DNS for delivering to clients; When the domain name resolution query of the specific web server comes from the service request client, a web cache cluster closest to the service request client is selected from a plurality of web cache clusters installed in each network, and the IP address of the selected neighbor web cache cluster is selected. Intelligent DNS for delivering to the service request client; And When the service request for the web document from the service request client comes, the web content delivery system consisting of the plurality of web cache cluster to form an information packet to the web request to the service request client. The system of claim 1, wherein the intelligent DNS selects the proximity web cache cluster according to a predefined rule. The web content delivery system of claim 1, wherein the intelligent DNS selects the proximity web cache cluster by referring to a traffic condition of a network. 4. The web content delivery system according to claim 1, 2 or 3, wherein each web cache cluster comprises a plurality of web cache servers. 5. The web cache cluster of claim 4, wherein each of the web cache clusters pre-caches predetermined content according to a passive method of caching content accessed by a first client to specific web document information, definitions and update rules received from a corresponding web server. And caching the content through a mirroring method of copying and caching some or all contents of the web server in advance according to an active method or a rule transmitted from the web server. 6. The web content delivery system of claim 5, wherein each web cache cluster caches content in a hybrid manner in which at least two of the passive, active, and mirroring methods are intermingled. In the web content transmission control method for serving a web document stored in a web server to a plurality of clients, When a domain name resolution query for a specific web server is received from an arbitrary client, the mapping table is searched to determine an intelligent DNS that is in charge of domain name resolution of the specific web server, and the access information for the determined intelligent DNS is requested for the service. Delivering to the client; Querying the determined intelligent DNS for domain name resolution of the specific web server; In response to the domain name resolution query, selecting a proximity web cache cluster closest to the corresponding client requesting a service among a plurality of web cache clusters installed in each network; Delivering the IP address of the selected proximity web cache cluster to the corresponding client; And And receiving a service of a web document from the proximity web cache cluster by using the IP address. 8. The method of claim 7, wherein the method selects the proximity web cache cluster according to a predefined rule. 8. The method of claim 7, wherein the method selects the proximity web cache cluster with reference to traffic conditions of a network. 10. The method of claim 7, 8 or 9, wherein each web cache cluster is a passive method of caching content accessed by a first client to specific web document information, and a definition and update rule received from the web server. Web content transmission control, wherein the content is cached through an active method of pre-caching predetermined contents or a mirroring method of copying and caching some or all contents of the web server in advance according to a rule received from the web server. Way. 11. The method of claim 10, wherein each web cache cluster caches content in a mixed manner in which at least two of the passive, active, and mirroring methods are mixed. In a web content delivery system for serving a web document stored in a web server to a plurality of clients, When a domain name resolution query for a specific web server comes from any client, the mapping table is searched to determine a redirector in charge of domain name resolution of the specific web server, and the access information for the determined redirector is sent to the service request client. Forwarding customer DNS; When the specific web document request is received from the service request client, a web cache cluster closest to the service request client is selected among a plurality of web cache clusters installed in each network, and the URL of the selected proximity web cache cluster is determined by the service request client. At least one redirector for transmitting to the at least one redirector; And When the service request for the web document from the service request client comes, the web content delivery system consisting of the plurality of web cache cluster to form an information packet to the web request to the service request client. The system of claim 12, wherein the redirector selects the proximity web cache cluster by referring to distance information provided from each web cache cluster and current traffic condition information of a network. The web content delivery system according to claim 12 or 13, wherein each web cache cluster comprises a plurality of web cache servers. 15. The method of claim 14, wherein each web cache cluster is configured to pre-cache predetermined content according to a passive method of caching content accessed by a first client to specific web document information, definitions and update rules received from a corresponding web server. And caching the content through a mirroring method of copying and caching some or all contents of the web server in advance according to an active method or a rule transmitted from the web server. 16. The web content delivery system of claim 15 wherein each web cache cluster caches content in a hybrid manner in which at least two of the passive, active, and mirroring methods are intermingled. In the web content transmission control method for serving a web document stored in a web server to a plurality of clients, When a domain name resolution query for a particular web document comes from any client, the customer DNS searches the mapping table to determine the redirector responsible for resolving the URL of the web cache cluster, and provides the service request client with connection information for the determined redirector. Delivery to Querying the determined redirector for domain name resolution of the specific web server; In response to the domain name resolution query, requesting service selection information from a plurality of web cache clusters installed in each network; Selecting a proximity web cache cluster closest to a corresponding client requesting a service among the plurality of web cache clusters based on the service selection information received from each web cache cluster; Delivering a URL of the selected proximity web cache cluster to the corresponding client; And And receiving a service of a web document from the proximity web cache cluster by using the URL. 18. The method of claim 17, wherein the service selection information is distance information between each web cache cluster and a service request client and current traffic state information of a network. 19. The method of claim 17 or 18, wherein each of the web cache clusters is configured in accordance with a passive method of caching content accessed by a first client to specific web document information, and a predetermined content according to a definition and update rule received from a corresponding web server. And caching the content through an active caching method for caching them in advance or a mirroring method for copying and caching some or all of the content of the web server in advance according to rules received from the web server. 20. The method of claim 19, wherein each web cache cluster caches content in a mixed manner in which at least two of the passive, active, and mirroring methods are mixed.