JP5343796B2 - Authentication apparatus, femtocell system, and accounting method used therefor - Google Patents

Description

  The present invention relates to an authentication apparatus, a femtocell system, and a charging method used for them, and more particularly to a charging method used for a femtocell system.

  In recent years, in order to eliminate the dead zone of mobile phones, a method of installing an ultra-small base station (femtocell or femtocell base station) covering an area of about several meters in a home or a small office is becoming widespread ( For example, see Patent Document 1). The small service area provided by this ultra-small base station is also called a femtocell.

The femtocell is advantageous to the user in that the mobile phone can be used in a comfortable radio wave state. In addition, femtocells are advantageous to communication carriers in terms of radio frequency shortage and area expansion, and many micro base stations [hereinafter referred to as femtocell APs (access points)] are installed and many users. However, the profit of the communication carrier increases as the communication through the femtocell AP is performed.

  In other words, it is better to make it possible for other users to use the femtocell AP installed by a certain user. However, the electricity bill and broadband line usage fee for operating the femtocell AP are set up by installing the femtocell AP. This is a burden on the user and causes unfairness.

To eliminate this injustice,
・ When a user with a femtocell AP communicates via the femtocell AP, the communication fee is discounted or free.
-When a user who is not a user installed with the femtocell AP performs communication via the femtocell AP, the communication carrier returns a part of the communication fee to the user installed with the femtocell AP.
The business model can be considered.

JP 2009-182619 A

  However, in the femtocell system charging method related to the present invention, service usage information provided by CSCF (Call Session Control Function) is used, and it is not known which femtocell AP is used for the service. The billing contents cannot be changed depending on which femtocell AP is used.

  In the charging method related to the present invention, there is no method for providing to the charging system which femtocell AP is used to provide the service to be charged. Since the access network usage fee is borne by the femtocell AP installation user, unfairness occurs when a user who is not a femtocell AP installation user uses an access network for which the femtocell AP installation user pays a usage fee. As one of countermeasures, there is a method for enabling only a user installed with a femtocell AP to use the femtocell AP. However, the advantage of a telecommunications carrier of expanding a service providing area is impaired.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an authentication apparatus, a femtocell system, and a charging method used therefor, which can solve the above-described problems and can change the charging contents depending on which femtocell AP is used. .

An authentication apparatus according to the present invention is an authentication apparatus that performs access authentication of a user terminal that uses a femtocell access point,
Means for storing in the AP information storage means the AP identifier of the femtocell access point used by the user terminal at the time of authentication of the user terminal;
Means for sending the AP identifier and the usage period of the femtocell access point used by the user terminal to the charging system.

  A femtocell system according to the present invention includes the authentication device described above.

Another femtocell system according to the present invention includes an authentication device that performs access authentication of a user terminal that uses a femtocell access point, a CSCF (Call Session Control Function) that stores a period during which the user terminal has used a service, A femtocell system including a charging system that charges the user terminal using a period in which the service provided by the CSCF is used,
The authentication device
Means for storing a period during which a user terminal of a user who has installed the femtocell access point or a user terminal other than the user who has installed the femtocell access point can use the access network using the femtocell access point When,
Means for sending the access information of the user terminal to the billing system.

The charging method according to the present invention includes an authentication device that performs access authentication of a user terminal that uses a femtocell access point, a CSCF (Call Session Control Function) that stores a period during which the user terminal has used a service, and the CSCF A charging method for use in a femtocell system including a charging system that charges the user terminal using a period of using the service,
The authentication device is
Storing a period during which a user terminal of a user who has installed the femtocell access point or a user terminal other than a user who has installed the femtocell access point has been in a state where the access network can be used using the femtocell access point; When,
A step of transmitting access information of the user terminal to the billing system.

  In the present invention, by adopting the configuration and operation as described above, it is possible to obtain an effect that the charge contents can be changed depending on which femtocell AP is used.

It is a block diagram which shows the structural example of AAA by this invention. It is a block diagram which shows the structural example of the femtocell system by embodiment of this invention. FIG. 3 is a block diagram illustrating a configuration example of AAA illustrated in FIG. 2. It is a block diagram which shows the structural example of the charging system of FIG. It is a sequence chart which shows the operation example of the femtocell system by embodiment of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. First, an outline of AAA (Authentication, Authorization, and Accounting) (authentication apparatus) according to the present invention will be described. The AAA according to the present invention is an authentication device that performs access authentication of a terminal of a femtocell user.

  The present invention stores an AP identifier of a femtocell AP (access point) used by a terminal at the time of authentication of the terminal in AAA, and provides the AP identifier and usage period of the femtocell AP used by the terminal to the charging system. Accordingly, the present invention provides a method that allows the charging contents to be changed depending on which femtocell AP is used by the terminal in the charging system.

FIG. 1 is a block diagram showing a configuration example of AAA according to the present invention. In FIG. 1, AAA (authentication apparatus) 1 includes an AP authentication processing unit 12, a terminal (subscriber) authentication processing unit 13, and a database 14. The database 14 includes a subscriber information table 15, AP information table 16 is provided.

  The AP authentication processing unit 12 is a processing unit when it is determined that AP authentication is performed by a signal receiving unit (not shown). The AP authentication processing unit 12 stores the AP position information included in the received signal in the AP information table 16 when AP access is authorized as a result of AP authentication.

  The terminal authentication processing unit 13 is a processing unit when it is determined that terminal authentication is performed by a signal receiving unit (not shown). When the received signal is an authentication request and the access of the terminal is authorized as a result of the terminal authentication, the terminal authentication processing unit 13 searches the AP information table 16 using the AP location information included in the received signal as a key and specifies the AP identifier. The terminal identifier, AP identifier, and use start time are stored in the access information.

  Further, the terminal authentication processing unit 13 stores the use end time in the access information when the received signal is a disconnection signal or when there is no re-authentication from the terminal for a certain period of time. If the PDG (Packet Data Gateway) does not have a function of adding AP location information, the terminal authentication processing unit 13 searches the AP information table 16 using the AP location information included in the received signal as a key to search for APs. The identifier cannot be specified. In this case, the AP identifier is registered in the subscriber information table 15 in a fixed manner, and the terminal authentication processing unit 13 obtains the AP identifier by searching the subscriber information table 15 using the terminal identifier as a key.

  AAA1 stores the period during which the femtocell user terminal (# 1) in which the femtocell AP is installed is in a state where the access network can be used using the femtocell AP, and the access information [[1] Terminal identifier that can uniquely identify the terminal (# 1), AP identifier of the AP used by the terminal (# 1), AP usage start time when the terminal (# 1) started using the access network using the AP, and terminal (# 1) provides the billing system with the AP use end time when the use of the access network is ended using the AP.

  On the other hand, the CSCF (Call Session Control Function) stores the period during which the terminal (# 1) has used the service (assuming a telephone service), and uniquely uses the service usage information of the terminal (# 1) [terminal (# 1). A terminal identifier that can be identified, a service use start time when the terminal (# 1) starts using the service, and a service use end time when the terminal (# 1) finishes using the service] are provided to the charging system.

  Further, AAA1 stores the period during which the terminal (# 2) of the user using the femtocell who is not the user who installed the femtocell AP (# 2) can use the access network using the femtocell AP, and the terminal (# 2) Access information to the billing system. On the other hand, the CSCF stores a period during which the terminal (# 2) has used the service, and provides service usage information of the terminal (# 2) to the charging system.

  As described above, in the present invention, it is possible to know which femtocell AP the terminal (# 1) and the terminal (# 2) used the service in the charging system, and use the information to calculate the communication fee. It can be utilized, and a part of the communication fee of the user using the femtocell AP can be returned to the user installing the femtocell AP.

  The billing system performs billing using service usage information provided by the CSCF. AAA1 changes the charging method depending on which femtocell AP the user uses in the charging system by providing the charging system with information on which femtocell AP the user has used the access network. Is possible.

  FIG. 2 is a block diagram showing a configuration example of the femtocell system according to the embodiment of the present invention. 2, the femtocell system according to the embodiment of the present invention includes AAA1, PDG2, CSCF3, femtocell AP4, terminals 5-1, 5-2, charging system 100, and customer management system 200. , An access network 301 and an IMS (Internet protocol Multimedia Subsystem) 302.

  The terminal 5-1 is a terminal used by a user who has installed the femtocell AP 4, and can receive a service using the IMS 302 after the use of the access network 301 is authorized by the AAA 1.

  The terminal 5-2 is a terminal used by a user who is not a user who has installed the femtocell AP4, and can receive a service using the IMS 302 after the use of the access network 301 is authorized by the AAA1.

  The femtocell AP4 is an AP installed by a user who uses the terminal 5-1. The PDG 2 is a device that transmits the authentication request of the femtocell AP4 and the authentication request from the terminal via the femtocell AP4 to the AAA1, and at this time, the APG information is added and transmitted to the AAA1.

  AAA 1 is an authentication server that performs access authentication of the femtocell AP 4, the terminal 5-1, and the terminal 5-2. The AAA 1 stores which femtocell AP the terminal uses as access information, and stores this access information in the charging system 100. The function of the present invention is provided.

  The charging system 100 is a system that acquires terminal service usage information from the CSCF 3 and terminal access information from the AAA 1 and charges the terminal user. The customer management system 200 is a system that provides the charging system 100 with the terminal identifier of the terminal used by the user and the AP identifier of the femtocell AP4 installed by the user.

  The PDG2, CSCF3, access network 301, and IMS 302 shown in FIG. 2 are well known to those skilled in the art and are not directly related to the present invention, and thus detailed description thereof is omitted [3GPP (3rd Generation Partnership Project) TS23. 234, 3GPP TS 23.228].

  The AAA 1 stores a period during which the femto cell user terminal 5-1 in which the femto cell AP 4 is installed can use the access network 301 using the femto cell AP 4, and access information 501 ( A terminal identifier that can uniquely identify the terminal, an AP identifier of the femtocell AP used by the terminal, an AP use start time at which the terminal starts using the access network using the femtocell AP, and a terminal that uses the femtocell AP AP use end time when the use of the access network is ended) is provided to the billing system 100.

  On the other hand, the CSCF 3 stores a period during which the terminal 5-1 has used the service (assuming a telephone service), and the service usage information 511 of the terminal 5-1 (a terminal identifier that can uniquely identify the terminal, and the terminal uses the service. The service use start time started and the service use end time when the terminal has finished using the service) are provided to the billing system 100.

  In FIG. 2, AAA 1 stores a period during which the access network 301 can be used using the femtocell AP 4 by the terminal 5-2 of the femtocell using user who is not the user who installed the femtocell AP 4. -2 access information 502 is provided to the charging system 100. On the other hand, the CSCF 3 stores a period during which the terminal 5-2 has used the service, and provides the service usage information 512 of the terminal 5-2 to the charging system 100.

  As described above, in the present embodiment, it is possible to know which femtocell AP the terminal 5-1 and the terminal 5-2 used in the charging system 100 and use the service, and calculate the communication fee. And a part of the communication fee of the user using the femtocell AP can be returned to the user installing the femtocell AP.

  The billing system 100 performs billing using service usage information provided by the CSCF 3. The AAA 1 provides the charging system 100 with information on which femtocell AP4 was used by the user to the charging system 100, so that a charging method can be selected depending on which femtocell AP4 the user used in the charging system 100. It becomes possible to change.

  FIG. 3 is a block diagram showing a configuration example of AAA1 shown in FIG. In FIG. 3, AAA 1 includes a signal receiving unit 11, an AP authentication processing unit 12, a terminal authentication processing unit 13, a database 14, and a signal transmission unit 18. The database 14 includes a subscriber information table 15, AP information table 16.

  The signal receiving unit 11 receives a signal from the PDG 2, determines whether it is AP authentication or terminal authentication, and distributes processing of the signal from the PDG 2.

  The AP authentication processing unit 12 is a processing unit when the signal receiving unit 11 determines that AP authentication is performed. The AP authentication processing unit 12 stores the AP position information included in the received signal in the AP information table 16 when AP access is authorized as a result of AP authentication.

  The terminal authentication processing unit 13 is a processing unit when the signal receiving unit 11 determines that terminal authentication is performed. When the received signal is an authentication request and the access of the terminal is authorized as a result of the terminal authentication, the terminal authentication processing unit 13 searches the AP information table 16 using the AP location information included in the received signal as a key and specifies the AP identifier. The terminal identifier, AP identifier, and use start time are stored in the access information 17.

  Further, the terminal authentication processing unit 13 stores the use end time in the access information 17 when the received signal is a disconnection signal or when there is no re-authentication from the terminal for a certain period of time. If the PDG 2 does not have a function of adding AP location information, the terminal authentication processing unit 13 searches the AP information table 16 using the AP location information included in the received signal as a key to identify the AP identifier. I can't. In this case, the AP identifier is registered in the subscriber information table 15 in a fixed manner, and the terminal authentication processing unit 13 obtains the AP identifier by searching the subscriber information table 15 using the terminal identifier as a key.

  The signal transmission unit 18 is a functional unit that creates authentication result signals of the AP authentication processing unit 12 and the terminal authentication processing unit 13 and transmits the signals to the PDG 2.

  FIG. 4 is a block diagram illustrating a configuration example of the charging system 100 of FIG. In FIG. 4, the billing system 100 includes a subscriber information table 101, an access information receiving unit 102, a service usage information receiving unit 103, a usage fee calculation function unit 104, a usage fee report creation function unit 105, and a memory 111. ~ 114.

  When the access information receiving unit 102 receives the access information from the AAA 1, the access information receiving unit 102 stores the information in the memory 112. When the service usage information receiving unit 103 receives the service usage information from the CSCF 3, the service usage information receiving unit 103 stores the information in the memory 113.

  In addition, the subscriber information table 101 acquires subscriber information (the terminal identifier of the terminal with which the subscriber has a contract and the AP identifier of the AP) from the customer management system 200 and stores the information in the memory 111.

  The usage fee calculation function unit 104 obtains access information stored in the memory 112, service usage information stored in the memory 113, and subscriber information stored in the memory 111, and a predetermined service usage fee calculation logic. Calculate the service charge according to The usage fee report creation function unit 105 creates a usage fee report from the calculation result of the usage fee calculation function unit 104, and stores the report in the memory 114.

  FIG. 5 is a sequence chart showing an operation example of the femtocell system according to the embodiment of the present invention. The operation of the femtocell system according to the embodiment of the present invention will be described with reference to FIGS.

  The femtocell AP4 transmits an authentication request for AAA1 to the PDG2 (a1 in FIG. 5). This authentication request includes the AP identifier of the femtocell AP4. When the PDG 2 transfers the authentication request of the femtocell AP 4 to the AAA 1, the PDG 2 attaches AP location information to the authentication request and transfers it to the AAA 1 (a 2 in FIG. 5).

  The AP location information is an example of a source IP address of an IP (Internet Protocol) packet received by the PDG 2 or a combination of a physical port number of the PDG 2 and a VLAN (Virtual Local Area Network) number (for example, where the AP is in the correct location). An example used in a confirmation method for confirming whether it is used) is not particularly defined in the present invention.

  Here, in the above confirmation method, when the PDG transmits an authentication request from the AP to the AAA, the IP address included in the authentication request from the AP is included in the transfer message to the AAA. The AAA associates the AP with the IP address in advance, and can confirm whether the AP is being used at the correct location based on whether the authentication request matches the set content. When a global IP address is fixedly assigned to a terminal, the IP address can be used as position information as described above.

  AAA1 authenticates and authorizes the femtocell AP4, and stores the AP location information in the AP information table 16 in combination with the AP identifier (a3 in FIG. 5). Thereafter, AAA1 transmits an authentication response to femtocell AP4 (a4 in FIG. 5).

  The terminal (terminal 5-1 or terminal 5-2) transmits an authentication request to AAA1 to PDG2 via femtocell AP4 (a5 in FIG. 5). The authentication request includes the terminal identifier of the terminal (terminal 5-1 or terminal 5-2).

  When transferring the authentication request of the terminal (terminal 5-1 or terminal 5-2), the PDG 2 attaches AP location information to the authentication request and transfers it to AAA1 (a6 in FIG. 5). Examples of the AP location information include a source IP address of an IP packet received by the PDG 2 and a combination of a physical port number and a VLAN number of the PDG 2, but are not particularly defined in the present invention as described above.

  AAA1 authenticates and authorizes the terminal (terminal 5-1 or terminal 5-2), and if it authorizes it, the access information (access information 501 in the case of terminal 5-1 and access information 502 in the case of terminal 5-2). The terminal identifier, AP identifier, and access network use start time are stored (a7 in FIG. 5). At this time, the AP identifier is obtained by searching the AP information table 16 using the AP position information transmitted in the process of a6 as a key.

  AAA1 transmits an authentication response to the terminal (terminal 5-1 or terminal 5-2) (a8 in FIG. 5). The terminal (terminal 5-1 or terminal 5-2) uses the service (a9 in FIG. 5). The contents of the service are not particularly defined in the present invention, but in the present embodiment, an IMS service such as a telephone using CSCF 3 is assumed.

  After the service ends, the CSCF 3 provides service usage information (service usage information 511 in the case of the terminal 5-1 and service usage information 512 in the case of the terminal 5-2) to the charging system 100 (a10 in FIG. 5). The service usage information includes a terminal identifier, a service usage start time, and a service usage end time.

  After the service ends, the terminal (terminal 5-1 or terminal 5-2) is disconnected from the access network 301 (a11 in FIG. 5). In this case, the terminal (terminal 5-1 or terminal 5-2) transmits a disconnection request, and the terminal within the access permission time authorized by the AAA1 for the terminal (terminal 5-1 or terminal 5-2). Re-authentication is not performed from (terminal 5-1 or terminal 5-2), and there is a disconnection due to timeout.

  AAA1 stores the use end time of the access network 301 as the access information 17 (access information 501 in the case of the terminal 5-1 and access information 502 in the case of the terminal 5-1) (a12 in FIG. 5). AAA1 provides access information 17 (access information 501 for terminal 5-1 and access information 502 for terminal 5-2) to billing system 100 (a13 in FIG. 5).

Accordingly, in the present embodiment, the service usage information of the charging system 100 (terminal 5-1 or terminal 5-2) (service usage information 511 in the case of the terminal 5-1 and service in the case of the terminal 5-2). the access information 501 in the case of use information 512) and access information (terminal 5-1, in the case of the terminal 5-2 can obtain the access information 502), the user who placed the femtocell AP4 from customer management system 200 When the charging system 100 calculates the service usage fee by acquiring the terminal identifier used by the user, the usage fee depends on whether the femtocell AP4 used when using the service is the femtocell AP installed by the user. Can be changed.

  For example, a) Access information transmitted from AAA 1 to charging system 100 is “AP usage start time: 2:00” and “AP usage end time: 4:00”, and b) is transmitted from CSCF 3 to charging system 100. When the service usage information is “service usage start time: 1:00” and “service usage end time: 3:00”, the billing system 100 determines “1:00 to 2:00” when requesting a service usage fee. Since it is accessed without using the femtocell AP4 installed by me, it is a normal fee, and "2:00 to 3:00" is accessed using the femtocell AP4 installed by me, so a discount fee, etc. You can calculate the service usage fee.

  In addition, said example is the information regarding the user who has installed femtocell AP4. That is, the same terminal identifier is included in a) and b), and the user using this terminal is the same user as the user who installed the femtocell AP4 of the AP identifier included in a). Being the same user is managed by the customer management system 200 and provided to the billing system 100.

  In addition, when a user who installs the femtocell AP4 receives a service using his / her femtocell AP4, a discount fee is applied.

Thus, in the present embodiment, AAA 1 identifies the AP identifier from the AP location information included in the authentication request of the terminal (terminal 5-1 or terminal 5-2), and the terminal (terminal 5-1 or terminal 5- since 2) to what period using any femtocell AP Do accessed is known, to provide information of the access to the billing system 100, Ithaca use any femtocell AP user in the accounting system 100 Thus, the charging method can be changed.

  The present invention is not limited to the above-described embodiment, and any authentication server that can know which femtocell AP is used by the terminal (terminal 5-1 or terminal 5-2) The present invention can also be applied to a femtocell system other than the IMS system.

  In addition, the present invention can be applied to services other than the telephone service as long as the service uses the femtocell AP and charges the service from the use start time / end time.

  The present invention can be applied to mobile communication targeting a femtocell.

1 AAA (authentication device)
2 PDG
3 CSCF
4 Femtocell AP
5-1, 5-2 terminal
11 Signal receiver
12 AP authentication processing part
13 Terminal authentication processing section
14 Database
15 Subscriber information table
16 AP information table
17 Access information
18 Signal transmitter
100 billing system
101 Subscriber information table
102 Access information receiver
103 Service usage information receiver
104 Usage fee calculation function
105 Usage Charge Report Creation Function Unit 111-114 Memory
200 Customer management system
301 Access network
302 IMS

Claims (12)

An authentication device that performs access authentication of a user terminal that uses a femtocell access point,
Means for storing in the AP information storage means the AP identifier of the femtocell access point used by the user terminal at the time of authentication of the user terminal;
An authentication apparatus, comprising: means for transmitting the AP identifier and a usage period of a femtocell access point used by the user terminal to a charging system.   The AP information storage means stores the AP identifier and the AP location information included in the received signal when the access of the femtocell access point is authorized when an authentication request from the femtocell access point is received. The authentication device according to claim 1. When the access request of the user terminal is authorized when receiving an authentication request from the user terminal, the AP information storage means is searched using the AP location information included in the received signal as a key to identify the AP identifier, and the user Storing the terminal identifier of the terminal, the identified AP identifier, and the use start time as access information;
When the received signal is a disconnection signal or when there is no re-authentication from the user terminal for a certain time, the use end time is stored as the access information,
3. The authentication apparatus according to claim 2, wherein the access information is sent to a billing system.   A femtocell system comprising the authentication device according to any one of claims 1 to 3. An authentication apparatus that performs access authentication of a user terminal that uses a femtocell access point, a CSCF (Call Session Control Function) that stores a period during which the user terminal uses a service, and a period during which the service provided by the CSCF is used A femtocell system including a charging system for charging the user terminal using
The authentication device
Means for storing a period during which a user terminal of a user who has installed the femtocell access point or a user terminal other than the user who has installed the femtocell access point can use the access network using the femtocell access point When,
Means for sending access information of the user terminal to the billing system.   The access information includes at least a terminal identifier that can uniquely identify the user terminal, an AP identifier of a femtocell access point used by the user terminal, and use of the access network by the user terminal using the femtocell access point. 6. The femtocell system according to claim 5, further comprising: an AP use start time at which the user terminal is started and an AP use end time at which the user terminal ends use of the access network using the femtocell access point. .   When the authentication device authorizes access to the femtocell access point when receiving an authentication request from the femtocell access point, the AP identifier and the AP location information included in the received signal are stored in the AP information storage unit The femtocell system according to claim 6. The authentication device is
When the access request of the user terminal is authorized when receiving an authentication request from the user terminal, the AP information storage means is searched using the AP location information included in the received signal as a key to identify the AP identifier, and the user Storing the terminal identifier of the terminal, the identified AP identifier, and the use start time as the access information;
When the received signal is a disconnection signal or when there is no re-authentication from the user terminal for a certain time, the use end time is stored as the access information,
8. The femtocell system according to claim 7, wherein the access information is transmitted to a billing system. An authentication apparatus that performs access authentication of a user terminal that uses a femtocell access point, a CSCF (Call Session Control Function) that stores a period during which the user terminal uses a service, and a period during which the service provided by the CSCF is used A charging method used in a femtocell system including a charging system that charges the user terminal using
The authentication device is
Storing a period during which a user terminal of a user who has installed the femtocell access point or a user terminal other than a user who has installed the femtocell access point has been in a state where the access network can be used using the femtocell access point; When,
And a step of transmitting access information of the user terminal to the charging system.   The access information includes at least a terminal identifier that can uniquely identify the user terminal, an AP identifier of a femtocell access point used by the user terminal, and use of the access network by the user terminal using the femtocell access point. The charging method according to claim 9, further comprising: an AP use start time at which the user terminal is started, and an AP use end time at which the user terminal ends use of the access network using the femtocell access point.   When the authentication device authorizes access to the femtocell access point when receiving an authentication request from the femtocell access point, the AP identifier and the AP location information included in the received signal are stored in the AP information storage unit The charging method according to claim 10, wherein: The authentication device is
When the access request of the user terminal is authorized when receiving an authentication request from the user terminal, the AP information storage means is searched using the AP location information included in the received signal as a key to identify the AP identifier, and the user Storing the terminal identifier of the terminal, the identified AP identifier, and the use start time as the access information;
When the received signal is a disconnection signal or when there is no re-authentication from the user terminal for a certain time, the use end time is stored as the access information,
12. The charging method according to claim 11, wherein the access information is sent to a charging system.

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