JP5404855B2 - CDN introduction status determination apparatus, CDN introduction status determination method, and program - Google Patents

Description

  The present invention relates to a technique for determining the introduction status of a CDN (Contents Delivery Network) in an AS (Autonomous System).

  By distributing content requests from users to a cache device close to the user, a CDN (Contents Delivery Network) is provided which reduces the load on the Internet backbone and smoothly delivers data to the user.

  In particular, traffic originating from a CDN (Contents Delivery Network) by a large-scale content provider is rapidly increasing. In the CDN, the distribution efficiency is improved by arranging the cache device in a large number of ASs (Autonomous Systems) and distributing the content from the cache device.

  Recently, content providers have arranged cache devices not only for large-scale AS but also for small-scale AS in order to expand CDN. For this reason, a lot of traffic is distributed from the cache device, and the origin of traffic that has been concentrated in the upper network in the past is distributed in the network. Understanding this is important for network operators to perform systematic and stable network operation management and design. For example, when a CDN is introduced in an AS, there is a possibility that traffic starting from that AS may increase, so that it is possible to make a determination to increase the link.

C. Labovitz, S. Iekel-Johnson, D. McPherson, J. Oberheide, and F. Jahanian, "Internet inter-domain traffic," SIGCOMM Comput. Commun. Rev., vol.40, no.4, pp.75 -86, Aug. 2010. "Understanding the total amount of traffic on the Internet in Japan," Ministry of Internal Affairs and Communications, http://www.soumu.go.jp/menu_news/s-news/01kiban04_02000031.html.

  In general, each AS does not announce the introduction status of CDN in its own network. For this reason, there is no choice but to judge the status of introduction through external measurement. However, there is currently no technology to do that. It is possible to estimate the introduction status of CDN from the change in traffic trend by performing large-scale traffic measurement (Non-Patent Document 1, Non-Patent Document 2) at multiple points, but the detection accuracy is low. There is a problem. Furthermore, it is difficult for a telecommunications carrier to perform multipoint traffic measurement alone.

  The present invention has been made in view of the above-described problems. A single communication carrier can clarify the introduction status of the CDN of the measurement target AS by external active measurement without performing multi-point traffic measurement. It aims at providing the means to do.

In order to solve the above problems, the present invention is a CDN introduction status determination apparatus for determining whether or not a CDN (Contents Delivery Network) is installed in a measurement target AS (Autonomous System),
Network connection means for connecting to the network of the measurement target AS;
IP address acquisition means for acquiring the IP address of the content acquisition destination host based on the input measurement destination CDN information;
AS number acquisition means for acquiring the AS number to which the IP address belongs from the IP address, and acquiring the AS number of the measurement target AS;
The AS number to which the IP address belongs is compared with the AS number of the measurement target AS, and when they match, it is determined that CDN has already been introduced into the measurement target AS. And a CDN introduction status judging device.

  When the access control method of the discrimination target CDN is DNS control, the measurement destination CDN information includes the host name of the content acquisition destination host of the content using the CDN, and the IP address acquisition means Requests name resolution of the host name, and obtains the IP address as a response to the request.

  When the access control method of the discrimination target CDN is Web server control, the measurement destination CDN information includes a URI of a download guide page to the content using the CDN, and the IP address acquisition unit is configured to generate HTML from the URI. A file is acquired, a host name of a content acquisition destination host is acquired from the HTML file, a name resolution of the host name is requested to the network, and the IP address is acquired as a response to the request.

  The present invention may also be configured as a CDN introduction status determination method executed by the CDN introduction status determination device. Further, the present invention may be configured as a program for causing a computer to function as each means of the CDN introduction status determination device.

  According to the present invention, the introduction status of CDN for a large number of ASs by using information obtained within a single carrier and a general ISP contract without performing traffic measurement at multiple points. Can be determined.

It is a figure for demonstrating operation | movement of CDN by DNS control. It is a figure for demonstrating operation | movement of CDN by Web server control. 1 is a configuration diagram of an entire system including a CDN introduction status determination system 30 according to an embodiment of the present invention. It is a functional block diagram of the CDN introduction condition discrimination device 32 concerning an embodiment of the invention. 4 is a flowchart for explaining the operation of a CDN introduction status determination device 32;

  Embodiments of the present invention will be described below with reference to the drawings. The embodiment described below is only an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

(About CDN operation)
In describing the embodiment of the present invention, first, the operation of the CDN will be described. The operation of the CDN is roughly classified into two types, that is, an operation based on DNS control and an operation based on Web server control from the viewpoint of an access control method. In either case, the purpose is to improve distribution efficiency by guiding access from a user terminal to a distribution server (cache server) close to the user terminal. Basically, in an AS in which a cache server is introduced, most of the accesses from users are directed to the cache server of the own AS.

<DNS control>
First, DNS control will be described with reference to FIG. In the example of FIG. 1, the user terminal 10, the DNS server 11, and the cache server 12 are shown in AS1, and the Web server 13 and the cache server 14 are shown in AS2.

  In the DNS control, as shown in FIG. 1, the above access guidance is performed by DNS (Domain Name System). First, when downloading content, the user terminal 10 acquires a URI (Uniform Resource Identifier) of the content from the Web server 13 (step 11). The same host name in this URI is returned for any AS. When this host name is forwarded from the DNS server 11, the IP (Internet Protocol) address of the server closest to the connection AS is returned (step 12). The user terminal 10 connects to the obtained IP address (step 13).

  When the DNS server 11 of AS1 is set to return the IP address of the nearest server as described above, it means that a CDN is installed in AS1. If the CDN is not introduced into the AS 1, as shown in step 14 in FIG. 1, the content is distributed by connecting to the server of another AS.

<Web server control>
Next, Web server control will be described with reference to FIG. In the example of FIG. 2, the user terminal 20, the DNS server 21, and the cache server 22 in AS1 are shown, and the Web server 23 and the cache server 24 in AS2 are shown.

  In the Web server control, as shown in FIG. 2, guidance from the user terminal 20 to the nearby cache server 22 is performed by the Web server 23 instead of the DNS. In the Web server 23, when notifying the content URI to the user terminal 20 on the content download guide page or the like (step 21), the IP address band of the access source (user terminal 20) is referred to and the host name of the nearest server is included. An HTML file including the URI is returned to the user terminal 21. In the DNS record, the same information is registered in any AS. The host name is resolved by the DNS server 21, the IP (Internet Protocol) address of the nearest server is returned to the user terminal 20 (step 22), and the user terminal 20 connects to the obtained IP address (step 23). .

  Thus, setting the Web server 23 to return a URI including the host name of the nearest server means that a CDN is installed in the AS 1 provided with the nearest server. If the CDN is not introduced into the AS1, as shown in step 24 of FIG. 2, the content is distributed by connecting to the server of another AS.

(Description of Embodiment of the Present Invention)
Based on the above, embodiments of the present invention will be described below.

<Principle of CDN introduction status discrimination technology>
First, the determination procedure will be described as the principle of the CDN introduction status determination technique according to the present embodiment. The discrimination procedure is divided into two according to the CDN access control method.

(1) Determination procedure in the case of DNS control Step 101) Check the host name of the download server of the content using the CDN.

  Step 102) The host name prepared in Step 101 is resolved from the host of the measurement target AS, and an IP address is obtained.

  Step 103) For the acquired IP address, the AS number to which the IP address belongs is acquired.

  Step 104) Obtain the AS number of the measurement target AS from the IP address of the measurement host.

  Step 105) If the AS number acquired in Step 103 is equal to the AS number of the measurement target AS, it is determined that the CDN is introduced into the measurement target AS.

  In the above discrimination method, the IP address of the access destination server (content acquisition destination server) is acquired in steps 101-102. For example, in FIG. 1, the DNS server 11 of AS1 (measurement target AS) performs name resolution from the host name in the URI acquired from the Web server 13, and the IP address of the cache server 12 (access destination server) is set. It corresponds to acquiring.

  In steps 103 to 105, the introduction status is determined by comparing the AS number to which the IP address of the access destination server belongs and the AS number of the measurement target AS. When both numbers are equal, it is determined that CDN has been introduced into the measurement target AS, and when the numbers are not equal, it is determined that CDN has not been introduced. For example, in AS1 in FIG. 1, it is determined that CDN has been introduced.

(2) Web Server Control Discrimination Procedure Step 201) Investigate the URI of the download guide page for content using the CDN.

  Step 202) Obtain an HTML file from the URI prepared in Step 201 from the host of the measurement target AS.

  Step 203) From the acquired HTML file, a host name of a moving image or an image is extracted, and the extracted host name is resolved by DNS to obtain an IP address.

  Step 204) For the acquired IP address, the AS number to which the address belongs is acquired.

  Step 205) Obtain the AS number of the measurement target AS from the IP address of the measurement host.

  Step 206) If the AS number acquired in step 204 is equal to the AS number of the measurement target AS, it is determined that the CDN is introduced into the measurement target AS.

  This method is basically the same as the discrimination method based on DNS control, but the IP address acquisition method of the access destination host in steps 201 to 203 is different. That is, steps 201 to 203 in the present method acquire an HTML file from a Web server specified as providing a download guide page for content using the CDN in FIG. This corresponds to extracting the destination host name and performing name resolution with the DNS server 21 to obtain the IP address of the cache server 22.

  As in the case of DNS control, the introduction number of the CDN is determined by comparing the AS number to which the IP address of the access destination server belongs in steps 204 to 206 with the AS number of the measurement target AS. When both numbers are equal, it is determined that CDN has been introduced into the measurement target AS, and when the numbers are not equal, it is determined that CDN has not been introduced. For example, in AS1 in FIG. 2, it is determined that CDN has been introduced.

<Overall system configuration>
FIG. 3 is a configuration diagram of the entire system including the CDN introduction status determination system 30 according to the present embodiment. In the configuration of FIG. 3, each component can communicate via a communication network.

  The CDN introduction status determination system 30 includes a CDN content detection device 31 and a CDN introduction status determination device 32. The CDN content detection device 31 is connected to the DNS server 33 and the packet capture device 34. The CDN introduction status determination device 32 is connected to the measurement target AS.

  The packet capture device 34 is a device having a function of capturing a packet flowing through the Internet 35 and collecting it as a log.

  As shown in FIG. 3, the CDN content detection device 31 acquires log data from the DNS server 33 and the packet capture device 34, creates a measurement destination list based on the log data, and the CDN introduction status determination device 32 displays the measurement destination. Investigate CDN introduction status based on the list. When performing measurement in a large number of ASs, the network setting of the CDN introduction status determination device 32 is switched to investigate the CDN introduction status.

  Hereinafter, each device of the CDN introduction status determination system 30 will be described in more detail.

<CDN content detection device 31>
The CDN content detection device 31 is a device that performs steps 101 and 201 in each of the above-described discrimination methods. That is, the CDN content detection device 31 acquires the DNS log data from the DNS server 33, acquires the packet capture log from the packet capture device 34, analyzes these logs, etc., and detects the CDN. Is determined to be DNS control or Web server control. When the specific target CDN is DNS control, the host name of the CDN server is detected, and in the case of Web server control, the URI of the download guide page to the content using the CDN is detected.

Then, the CDN content detection apparatus 31 passes the measurement destination list describing the combination of the identification result, the CDN name, and the CDN control type to the CDN introduction status determination apparatus 32. The measurement destination list is as follows, for example. Here, the CDN_Type field indicates the type of CDN control, 1 is DNS control, and 2 is Web server control.
# CDN_Name, Host_Name / URI, CDN_Type
CDN_A, hoge.hoge.com, 1
CDN_B, 123.456.ac.jp, 1
CDN_C, http://abc.def.co.jp/index.html, 2
CDN_D, http://downlode.ne.jp/download.html, 2
The measurement destination list is not limited to the above format. Further, the method of acquiring the measurement destination list is not limited to the above example. The measurement destination list acquired by another method may be input to the CDN introduction status determination device 32 to determine the CDN introduction status.

<CDN introduction status determination device 32>
The CDN introduction status discriminating device 32 is a device that executes steps 102/202 and subsequent steps of each discriminating method on the host name / URI in the measurement destination list delivered from the CDN content detection device 31. Further, the CDN introduction status determination device 32 needs to perform measurement from the network interface in which the IP address of the measurement target AS and the DNS server are set. The network environment of the measurement target AS is prepared in advance by making a contract with a general ISP operated by the measurement target AS. When there are a plurality of measurement targets AS, measurement is performed by switching the network setting for each measurement.

  FIG. 4 shows a functional configuration diagram of the CDN introduction status determination device 32. As shown in FIG. 4, the CDN introduction status determination device 32 according to the present embodiment includes a measurement destination list input unit 321, a network connection unit 322, an IP address acquisition unit 323, an AS number acquisition unit 324, and a CDN introduction determination unit 325. The determination result output unit 326 is included.

  The CDN introduction status determination apparatus 32 according to the present embodiment is a program corresponding to each functional unit described in the present embodiment, for example, in a computer including a CPU, a storage unit such as a memory and a hard disk, and a data communication unit. This can be realized by executing. The program may be stored in a storage medium such as a portable memory and distributed, installed on the computer, or downloaded from a server on a network and installed on the computer.

  Hereinafter, an operation example of the CDN introduction status determination device 32 realized by each of the above functional units will be described with reference to the flowchart of FIG. As a premise of the operation, it is assumed that the IP address and DNS server of the measurement target AS are set in the network connection unit 322 that performs network connection, and the network connection in the measurement target AS is performed.

  Step 301) The measurement list delivered from the CDN content detection device 31 is input to the measurement destination list input unit 321 and stored in the storage means of the CDN introduction status determination device 32, and one measurement destination CDN from the input list. Information (host name or URI, CDN type) is passed to the IP address acquisition unit 323.

  Step 302) The IP address acquisition unit 323 determines whether the discrimination target CDN is DNS control or Web server control from the CDN type of the measurement destination CDN information. If it is Web server control, the process proceeds to Step 303. Proceed to step 305.

  Step 303) In Step 303 when the discrimination target CDN is Web server control, the IP address acquisition unit 323 accesses a download guide page corresponding to the URI and acquires an HTML file.

  Step 304) The IP address acquisition unit 323 extracts a host name to which content such as a moving image or an image is acquired from the HTML file acquired in Step 303.

  Step 305) In step 305 and subsequent steps, the same processing is performed regardless of whether the discrimination target CDN is CDN control or Web server control. In step 305, the host name extracted in step 304 or the host name included in the measurement destination CDN information when the CDN control is DNS control is resolved by the DNS in the measurement target AS, and an IP address is acquired. That is, the DNS server is requested to resolve the host name, and the IP address is acquired as a response to the request. The acquired IP address is passed to the AS number acquisition unit 324.

  Step 306) Acquires the AS number (AS number of the content acquisition destination host) to which the IP address belongs from the IP address acquired in Step 305, and assigns it to the measurement host IP address (for example, the CDN introduction status determination device 32) From the (IP address), the AS number to which the IP address belongs (AS number of the measurement target AS) is acquired. Note that obtaining the AS number of the IP address from the IP address is an existing technology. The AS number of the content acquisition destination host and the AS number of the measurement target AS are passed to the CDN introduction determination unit 325.

  Step 307) The CDN introduction determination unit 325 compares the AS number of the content acquisition destination host with the AS number of the measurement target AS, and checks whether they match. If they match, it is determined that CDN is introduced into the measurement target AS, and if they do not match, it is determined that CDN is not introduced into the measurement target AS.

  Step 308) The determination result output unit 326 outputs the determination result in Step 307.

  The above processing is performed for each measurement destination included in the measurement destination list. Examples of measurement results in a certain AS are shown below. Result item is the result, ○ indicates that it has been introduced and × indicates that it has not been introduced.

# CDN_Name, Host_Name / URI, CDN_Type, Result
CDN_A, hoge.hoge.com, 1, ○
CDN_B, 123.456.ac.jp, 1, ×
CDN_C, http://abc.def.co.jp/index.html, 2, ○
CDN_D, http://downlode.ne.jp/download.html, 2, ○
(Effect of embodiment)
As described above, by using the technology of the present embodiment, without using traffic measurement at multiple points, by using information obtained within a single communication carrier and a general ISP contract, The introduction status of the CDN can be determined for a large number of ASs.
The present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

10, 20 User terminal 11, 21 DNS server 12, 14, 22, 24 Cache server 13, 23 Web server 30 CDN introduction status determination system 31 CDN content detection device 32 CDN introduction status determination device 33 DNS server 34 packet capture device 35 Internet 321 Measurement destination list input unit 322 Network connection unit 323 IP address acquisition unit 324 AS number acquisition unit 325 CDN introduction determination unit 326 determination result output unit

Claims (7)

A CDN introduction status determination device for determining whether a CDN (Contents Delivery Network) is installed in a measurement target AS (Autonomous System),
Network connection means for connecting to the network of the measurement target AS;
IP address acquisition means for acquiring the IP address of the content acquisition destination host based on the input measurement destination CDN information;
AS number acquisition means for acquiring the AS number to which the IP address belongs from the IP address, and acquiring the AS number of the measurement target AS;
The AS number to which the IP address belongs is compared with the AS number of the measurement target AS, and when they match, it is determined that CDN has already been introduced into the measurement target AS. A CDN introduction status determining device comprising: a CDN introduction determining means for determining When the access control method of the discrimination target CDN is DNS control, the measurement destination CDN information includes the host name of the content acquisition destination host of the content using the CDN,
2. The CDN introduction status determination apparatus according to claim 1, wherein the IP address acquisition unit requests the network to resolve the host name and acquires the IP address as a response to the request. When the access control method of the determination target CDN is Web server control, the measurement destination CDN information includes a URI of a download guide page to content using the CDN,
The IP address acquisition unit acquires an HTML file from the URI, acquires a host name of a content acquisition destination host from the HTML file, requests name resolution of the host name from the network, and returns the host name as a response to the request An IP address is acquired. The CDN introduction status discrimination device according to claim 1 or 2. A CDN introduction status determination method executed by a CDN introduction status determination device for determining whether a CDN (Contents Delivery Network) is installed in a measurement target AS (Autonomous System),
A network connection step of connecting to the network of the measurement target AS;
An IP address acquisition step of acquiring an IP address of a content acquisition destination host based on the input measurement destination CDN information;
An AS number acquisition step of acquiring the AS number to which the IP address belongs from the IP address, and acquiring the AS number of the measurement target AS;
The AS number to which the IP address belongs is compared with the AS number of the measurement target AS, and when they match, it is determined that CDN has already been introduced into the measurement target AS. And a CDN introduction status determining method comprising: a CDN introduction determining step. When the access control method of the discrimination target CDN is DNS control, the measurement destination CDN information includes the host name of the content acquisition destination host of the content using the CDN,
5. The CDN introduction status determination method according to claim 4, wherein in the IP address acquisition step, the network is requested to resolve the host name, and the IP address is acquired as a response to the request. When the access control method of the determination target CDN is Web server control, the measurement destination CDN information includes a URI of a download guide page to content using the CDN,
In the IP address acquisition step, an HTML file is acquired from the URI, a host name of a content acquisition destination host is acquired from the HTML file, name resolution of the host name is requested to the network, and a response to the request An IP address is acquired. The CDN introduction status determination method according to claim 4 or 5.   A program for causing a computer to function as each unit of the CDN introduction status determination apparatus according to any one of claims 1 to 3.

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