KR101073659B1 - Transparent Method for File Download to Reduce the Network Congestion - Google Patents

Abstract

According to the present invention, when a plurality of clients belonging to a network want to download the same content from a server in an external network, the number of request messages related to a client section is determined in the gateway of the client section instead of distributing traffic concentrated in the server section. A method for downloading a file in a network connection structure consisting of a client, a gateway, and a server, wherein the gateway receives a download request for a file from the client. Searching for whether the requested request file is stored in the file cache in the gateway; and if the request file is not stored in the file cache in the gateway, the request file is received from the server through a TCP connection with the server. The file cache Storing the request file in the file cache in the gateway, and redirecting the TCP connection from the client to the server to the local file server in the gateway to remove network traffic from the external server; And retrieving the request file stored in the file cache in the gateway and transmitting the retrieved file to the requesting client.

File Download, Network Congestion, Transparency, TCP Redirection

Description

Transparent method for file download to reduce the network congestion

The present invention relates to a network communication method, and more particularly, to a transparent file download method for reducing network congestion when simultaneously downloading the same content from a plurality of clients belonging to one network.

With the development of the Internet, many applications are taking advantage of network communication and file transfer. In recent years, existing office applications used in personal computers have also been provided as web applications in the form of SaaS (Software as a Service) over the Internet, enabling document, video sharing and collaboration. Accordingly, the accessibility of the user is improved, and information sharing and security problems can be easily solved. In addition, many methods have been proposed and used in the field of education using the web, and the traffic on the Internet is expected to increase continuously.

Recently, there has been a rapid increase in applications that download large files such as videos and still images through YouTube or P2P, resulting in more Internet traffic. When downloading a file, the network traffic is concentrated on a specific server, and when the traffic is increased in the network between server sections, network performance decreases rapidly. Commonly used to reduce this network traffic is to use a lot of mirroring techniques for caching specific content, such as a web proxy that handles web traffic, or to distribute the traffic concentrated on the server do.

1 is a block diagram illustrating a general network connection structure. When a gateway 30 is designated when a client 10 is set, a connection is made with another server 40 on the Internet through the designated gateway 30. When there are many clients in one place, such as a computer lab in a university, a connection hub or switch 20 is used to connect to the outside to prevent traffic collisions.

When configured in this manner, as shown in FIG. 2, when requesting a TCP connection for file transfer from client 10 to server 40, a gateway (G / W) (or router) 30 is requested. Through the TCP connection to the server 40 is made. When the server receives a file download request, the server retrieves the relevant file from the repository along with a response and sends the requested file to the client.

However, when accessing the same content of a specific server for a similar time interval in the client interval among the client-server interval, the traffic increases in the network interval to which the clients belong, so it is difficult to solve this problem by the existing server interval traffic distribution method. In other words, when multiple clients in the same network access the same content at the same time, the network performance decreases due to the increase of traffic at the gateway or router at the point connecting the network to another network.

In order to alleviate such network degradation and improve overall performance, these problems must be solved at the gateway or router of the network to which the client belongs.

Accordingly, the present invention has been made to solve the above problems, and distributed the traffic concentrated in the server interval when a plurality of clients belonging to one network to download the same content from a server in the external network The purpose of the present invention is to provide a method of reducing network traffic by reducing the number of related request messages at the gateway of the client interval.

Another object of the present invention is to ensure that network performance is not guaranteed by simply distributing traffic to a specific server as in the case of downloading a large file, thus sharing external network bandwidth with clients existing in other networks. The present invention provides a method of downloading a transparent file for reducing network congestion that can reduce overall network communication performance by reducing traffic to and from the external network so as to reduce the impact on the network.

The transparent file download method for reducing network congestion according to the present invention for achieving the above object is a transparent file download method in a network connection structure consisting of a client, a gateway, and a server, (A) when a download request for a file is input from the client, determining whether the input request file req is an HTTP file or an FTP file, and (B) whether the input request file is an HTTP file or FTP. A first search step for searching whether the requested request file is stored in a file cache in the gateway, and (C) if the request file is stored in the file cache in the gateway, the client Network traffic to and from external servers by redirecting TCP connections from the server to the server And removing (D) retrieving the request file stored in the file cache in the gateway and transmitting the retrieved file to the requesting client.

Preferably, (E) if the request file is not stored in the file cache in the gateway, receiving the request file through the TCP connection to the server; and (F) requesting the file received from the server. And storing the file in the gateway and transmitting the request file to the client.

Preferably, the step (F) is characterized by storing the file transmitted from the server in the file cache through packet sniffing (packet sniffing).

Preferably, the state change of the file cache is a step of retrieving a packet being transmitted to the server through packet sniffing and entering a 'Request' state when there is a new file request, and when a file header for the file is received from the server. Starting to store in the file cache is in the 'Download' state, and in the 'Download' state, the file segment (segment) transmitted from the server is stored through packet sniffing, and if a file trailer (file trailer) is found, Stored 'state, and if a new request for the same file is found in the' Stored 'state, it is placed in the' Service 'state, and redirects the packet transmitted to the external server to the local file server in the gateway. Characterized in that it comprises a step.

The transparent file download method for reducing network congestion according to the present invention as described above has the following effects.

First, there is an advantage that the network does not need to be explicitly configured in the client like the existing proxy configuration by allowing the gateway to service the related packet without changing the network-related configuration in the client side.

Second, the network traffic in the client section is greatly reduced, thereby improving the file download performance, thereby improving overall network performance.

Third, since the gateway of the client section is used as a server, file download is processed, and the number of connection hops between the client and the server is reduced, thereby improving overall network performance.

Fourth, it is possible to improve the communication performance of the network by enabling the download of the same content even while the first file is being downloaded, rather than being completely stored.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments with reference to the accompanying drawings.

A preferred embodiment of the transparent file download method for reducing network congestion according to the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be embodied in various forms, and only the present embodiments are intended to complete the disclosure of the present invention and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

3 is a diagram illustrating a network connection structure according to an embodiment of the present invention.

As shown in FIG. 3, at least one client 100, a switch 200, a download gateway 300, and a server 400 are configured.

The difference from the existing network connection structure includes a file cache for storing information on a file to be downloaded to the gateway 300 and a download management unit 350 for managing the file to further download the file to the file to be downloaded. Information is configured to be managed by the gateway 300 instead of the server 400.

That is, as shown in FIG. 4 (a), the file transmitted from the server 400 is captured by the gateway 300 and stored in the file cache for a certain period of time. Subsequently, when a download request for a file in a file cache in the gateway 300 is started through the client 100, as shown in FIG. 4 (b), the download request is not sent to the server 400 to the gateway 400. The file request is transmitted and processed to download the request file to the client 100 using the file stored in the file cache.

As such, the gateway 300 reduces the load of the server 400 and concentrates the gateway 400 at the same time as the server 400 does not send a download request for the request file stored in the internal file cache. Download can be drastically reduced the load due to file retransmission, thereby improving network performance.

With reference to the accompanying drawings, the transparent file download method according to the present invention through the network connection structure having such a structure will be described in detail as follows.

5 is a flowchart illustrating a transparent file download method for reducing network congestion according to an embodiment of the present invention.

Referring to FIG. 5, if a download request for a file is input from the client 100 (S10), it is determined whether the input request file req is an HTTP file or an FTP file (S20). That is, since the client 100 requests to download a file through an FTP program or a web browser, it is determined that the request file req is not a request file from the client 100 when the request file req is an HTTP file or not an FTP file. do.

Subsequently, if it is determined that the input request file is an HTTP file or an FTP file, the download manager 310 searches whether the request file requested from the client 100 is stored in the file cache in the gateway 300. 1 search) (S30).

When the request file is not stored in the first search result (S30) or the file cache in the gateway 300, the gateway 300 connects the gateway 300 to the requested TCP connection for the file transfer from the client 100 to the server 400. Through the TCP connection to the server 400 is made. Then, when the server 400 receives the file download request, the server 400 detects the file segment in the traffic of the requested signal (S40).

After determining whether the detected file segment is a file segment requested by the client 100 (S50), the determination result stores the related file segment in a file cache in the gateway and transmits the stored file segment to the client 100. (S60). Subsequently, the server 400 repeats the transmission process until all request files are detected in the storage (S70).

In this case, when the file header for the corresponding file is transmitted from the server 400, the gateway 300 captures the information about the beginning and the end of the file format by referring to the configuration file. Note that the method of capturing files in transit on the network can be easily handled by using a tool such as tcpxtract that uses the libpcap library to capture network packets.

Based on the information about the beginning and end of the captured file format, the gateway 300 stores the file segment transmitted from the server 400 in a file cache through packet sniffing, and stores a file trailer ( If the file trailer is found, the storing is terminated.

In addition, when the request file is stored in the first search result S30 and the file cache in the gateway 300, the download manager 310 makes a TCP connection from the client 100 to the server 400. Redirection to my local file server will remove network traffic to and from the external server 400 (S80). Note that redirecting a TCP connection to the server 400 to a local file server in the gateway 300 is possible by changing the settings for the INPUT, OUTPUT, and FORWARD chains as in iptables.

The gateway 300 searches for the request file stored in the file cache in the gateway 300 and transmits the searched file to the requesting client 100 (S90).

FIG. 6 is a diagram illustrating a state change of a file cache used in a gateway according to an embodiment of the present invention using a UML state diagram. FIG.

As illustrated in FIG. 6, the download manager 350 in the gateway 400 searches for a packet being transmitted to the server 400 through packet sniffing and enters a 'Request' state when there is a new file request. At this time, when the file header for the file is received from the server 400, the file is started to be stored in the file cache and is in a 'download' state. In the 'Download' state, the file segment transmitted from the server 400 is stored through packet sniffing, and when the file trailer is found, the file segment is in the 'Stored' state. In addition, in the 'Stored' state, when a new request for the same file is found, the service is in the 'Service' state. It is possible to eliminate network traffic to and from the external server 400 by rerouting.

Thus, by replacing the file download function of the external server 400 in the gateway 300, it is possible to reduce the effect on the network of the server section to improve the overall network performance.

Hop count Wireless network throughput Wired Network Throughput
(95% confidence interval) One 515.00 1236.30 ± 1.94 2 253.75 696.34 ± 1.78 3 160.00 463.79 ± 0.89 4 127.50 347.39 ± 1.36 5 97.50 277.95 ± 1.29 6 66.25 231.81 ± 0.87

The throughput of wired network shown in Table 1 is the result of experiment using ns-2 simulator. It is assumed that the connection between nodes is wired and the connection speed is 10Mbps. In order to increase the reliability of the simulation results, we performed 20 iterations and obtained 95% confidence intervals using the t-distribution.

As shown in Table 1, it can be seen that when the number of hops between nodes is changed to 1 to 6, the average throughput decreases rapidly. This means that as the transmission path length increases, network throughput decreases. Therefore, when using the method proposed in this specification, the server 300 plays a role of the gateway 300 in the same network instead of the server 400 in the external network. In this case, the entire transmission path is shortened, thereby improving network performance regardless of the wired or wireless environment.

Number of client nodes Traditional way
(95% confidence interval) Proposed method
(95% confidence interval) Performance improvement
((AB) * 100
/ A%) 5 133.20 ± 0.99 104.55 ± 0.67 21.60 10 275.75 ± 0.44 120.49 ± 1.40 56.30 15 412.78 ± 0.41 144.67 ± 3.48 64.95 20 530.64 ± 0.32 167.62 ± 6.14 68.41 25 655.56 ± 0.10 195.31 ± 8.66 70.21 30 785.91 ± 0.07 218.52 ± 9.63 72.20

Table 2 analyzes the overall network performance by increasing the network traffic by changing the number of client nodes from 5 to 30 in the existing network structure and the proposed network structure. To increase the reliability of the simulation results, 20 replicates were performed for each experiment, and the 95% confidence intervals were determined using the t-distribution.

As shown in Table 2, it can be seen that as the number of client nodes requesting file downloads increases, the performance improvement is about 21% to 72% compared to the conventional method. In other words, the existing method is a bottleneck caused by traffic collision at the gateway, it does not fully utilize the network bandwidth of the client interval. On the other hand, if the method proposed in the present specification is applied, even if a file download request is made at the same time, since only one file download request is processed through the gateway, the bottleneck caused by traffic collision in the network of the external section is reduced. When the file download is complete, the gateway replaces the FTP server's functionality, improving overall network performance.

Although the technical spirit of the present invention described above has been described in detail in a preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a block diagram showing a general network connection structure

FIG. 2 is a diagram illustrating a TCP connection process when a file is downloaded from a server through an FTP program or a web browser on a client through the structure of FIG.

3 is a configuration diagram showing a network connection structure according to an embodiment of the present invention;

4 (a) and (b) are diagrams illustrating a TCP connection process when a file is downloaded from a server through an FTP program or a web browser on a client through the structure of FIG.

5 is a flowchart illustrating a file download method for reducing network congestion according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a state change of a file cache used in a gateway according to an embodiment of the present invention using a UML state diagram. FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

100: client 200: switch

300: Gateway 310: Download Manager

400: server

Claims (4)

In the transparent file download method in a network connection structure consisting of a client, a gateway, and a server, the gateway (A) when a download request for a file is input from the client, determining whether the input request file req is an HTTP file or an FTP file; (B) if it is determined that the input request file is an HTTP file or an FTP file, a first search step of searching whether the requested request file is stored in a file cache in a gateway; (C) if the request file is stored in the file cache in the gateway, redirecting a TCP connection from the client to the server to a local file server in the gateway to eliminate network traffic to and from an external server; (D) searching for the request file stored in the file cache in the gateway and transmitting the searched file to the requesting client, (E) if the request file is not stored in the file cache in the gateway, receiving the request file through the TCP connection to the server; (F) storing the request file received from the server in a file cache in the gateway, and transmitting the request file to a client. delete The method of claim 1, The step (F) is a file download method for reducing network congestion, characterized in that for storing the file transmitted from the server through a packet sniffing (packet sniffing). The method of claim 1, wherein the state change of the file cache is Searching for packets being sent to the server through packet sniffing and entering a 'Request' state when there is a new file request, When the file header for the file comes from the server, the step of starting to store in the file cache to the 'Download' state, In the 'Download' state, the file segment transmitted from the server is stored through packet sniffing, and when the file trailer is found, the file segment is placed in the 'Stored' state. If a new request for the same file is found in the 'Stored' state, the service is in a 'Service' state, and rerouting the packet transmitted to the external server to the local file server in the gateway. How to download files to reduce network congestion.

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