JP2007235556A - Relay server, and method and program for controlling connection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable system capable of maintaining a communication route while achieving the load dispersion of call control apparatuses. <P>SOLUTION: A relay server connected between a client terminal and connection control apparatuses is provided with: a connection establishment means for selecting one of connection control apparatuses when a communication establishment request is received from the client terminal and establishing connection to the selected connection control apparatus; an address notification means for notifying address information for connecting the selected connection control apparatus to the client terminal; and a relay connection means for receiving a connection request based on the address information from the client terminal and relaying and connecting the client terminal to the connection control apparatus corresponding to the address information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a relay server, and more particularly to a relay server that accepts a connection request from a client terminal and relays it to a connection control server.

  In recent years, infrastructure for ADSL and optical networks has been improved, Internet access speed has increased, and many companies have started IP fixed-line telephone services. In the mobile network, services such as mail and packet communication by browser are still mainstream at present, but it is fully conceivable that the service will eventually be shifted to IP phones. Furthermore, in the 3GPP standardization organization, the standardization of the IMS (IP Multimedia Subsystem) system that implements IP multimedia service in the mobile network is underway. Reliability and quality equivalent to or higher than those of voice calls are required, and there is a need to ensure high reliability by an uninterrupted communication system.

  As described above, in the call control server that plays a central role in the IP telephone service that has been spreading in recent years, load distribution against an increase in traffic is an important issue in constructing a system. In the conventional IP telephone system, a subscriber data management server that manages location information and a call control server are integrated, and a signal from a client is sent to a specific call control server having subscriber data. Only exchanged signals. Further, since the subscribers accommodated in each server are fixedly allocated in advance, the load is distributed by adding servers as the number of subscribers increases.

  However, the above method has a problem that the load is temporarily increased or the risk cannot be distributed. In other words, service operation by a single server is not reliable from the viewpoint of server processing capacity and fault tolerance, and load distribution is performed to improve robustness (robustness) by changing the processing capacity flexibly according to failure and load. In addition, there has been a need to construct a system capable of risk dispersion.

JP 2003-273903 A

  On the other hand, in order to distribute the load from the client, a method such as load balancing using a server load balancing device is known. However, although the server load distribution device can be easily applied to an application server such as a Web server, there are some problems to use in a call control server. For example, since the call processing signal from the start to the end of the call needs to pass through the same call control server, the load balancer needs a function for managing session information, and there is a concern about performance degradation. Further, there is a security problem that user authentication cannot be performed because the call control server changes for each call by the distributed device. For this reason, since the call control server needs to acquire subscriber information for user authentication and registration processing, any call control server can access the subscriber data section so that the call control server can perform load balancing. The system needed to be built into the system.

  In addition, registration information is usually held in the call control server in addition to the subscriber data section, so that a call request by a SIP or the like from a client can be routed through the registered call control device to the load balancer. It was necessary. For this reason, in the load balancer, it is necessary to perform session management in order to decode and distribute the content of the SIP message, but such a technique has not been developed yet. Note that the above-described Patent Document 1 discloses a mechanism for distributing the load as described above.

  In addition, even if load balancing is performed with a load balancer, there is a problem that it is difficult to distribute the risk because the signal concentrates on the load balancer when considering disaster countermeasures. .

  For this reason, the present invention improves the inconvenience of the above-described conventional example, and particularly provides a highly reliable system that can maintain the communication path while realizing load distribution of the call control device. Objective.

Therefore, one aspect of the present invention is
A computer connected to the client terminal and the connection control device,
Select at least one connection control device according to the access from the client terminal, notify the client terminal of access information to the connection control device, accept a connection request from the client terminal based on the access information, and handle the access information Having a function of relay connecting the client terminal to the connection control device.
It is characterized by that.

More specifically, a relay server connected between the client terminal and the connection control device,
Connection establishment means for selecting one of the connection control devices when receiving a communication establishment request from the client terminal and establishing a connection to the selected connection control device;
Address notification means for notifying the client terminal of address information for connecting to the selected connection control device;
A relay connection unit that accepts a connection request based on address information from a client terminal and relay-connects the client terminal to a connection control device corresponding to the address information;
It is characterized by having.

  According to the above invention, first, a relay server that has received a communication establishment request from a client terminal selects one of the connection control devices and establishes a connection to the selected connection control device. Then, the client terminal is notified of address information for connecting to the connection control device. Thereafter, when a connection request is received from the client terminal based on the notified address information, the client terminal is relay-connected to the connection control device corresponding to the address information. Therefore, since a connection control device that performs connection control for each client terminal is assigned by the relay server and a connection request is issued from the client terminal based on the address of the connection control device notified at this time, load distribution of the connection control processing is reduced As shown, connection control is performed for each client terminal by the same connection control device, so that the connection can be stabilized and a highly reliable connection control process can be realized.

  The connection establishing means selects one connection control device according to the operation status of the connection control device. In particular, the connection establishment means selects one connection control device according to whether the connection control device is normal or failed, or selects one connection control device according to the load status of the connection control device. It is a feature. And a connection control device information storage means; a monitoring means for communicating with the connection control device to monitor the operation status of the connection control device and storing the operation status in the connection control device information storage means; The means is characterized in that one connection control device is selected based on information in the connection control device information storage means. The connection relay means receives a location registration request from the client terminal as a connection request.

  Accordingly, by monitoring the status of the connection control device to be relayed in advance and registering such status, a connection control device that can be connected in advance can be assigned to the client terminal. At this time, by monitoring and considering the load status of the connection control device and the like, more even load distribution can be realized, and further improvement in reliability can be achieved.

  In the present invention, the relay server described above and a connection control device are provided, and the connection control device performs call control of other client terminals in response to a request from a client terminal relay-connected by the relay server. Provides a call control system.

  The call control system includes a location server that stores location registration information of a client terminal that is a mobile terminal, and information in the location server is referenced from a plurality of connection control devices during call control by the connection control device. It is possible information. Further, the present invention is characterized in that a mirror server that stores the same information as the information in the location server and can be referred to from a plurality of connection control devices is provided.

  As a result, the call control device and the location server are separated, but because each call control device can refer to the information of the client, it is possible to take a plurality of connection paths, and to distribute the risk, The reliability of the entire system can be improved. Since the location server is mirrored, the reliability of the system can be further improved.

In the present invention,
To the relay server connected between the client terminal and the connection control device,
Connection establishment means for selecting one of the connection control devices when receiving a communication establishment request from the client terminal and establishing a connection to the selected connection control device;
Address notification means for notifying the client terminal of address information for connecting to the selected connection control device;
Relay connection means for accepting a connection request based on address information from a client terminal and relay-connecting the client terminal to a connection control device corresponding to the address information;
Provides a program to achieve this.

And this program
Monitoring means for communicating with the connection control device to monitor the operation status of the connection control device, and storing the operation status in the connection control device information storage means;
The connection establishment means operable to select one connection control device based on information in the connection control device information storage means;
It is also characterized by realizing.

Furthermore, a connection control method according to another aspect of the present invention includes:
A computer connected to the client terminal and the connection control device is a connection control method in which the client terminal is relay-connected to the connection control device,
One connection control device is selected in response to an access from the client terminal, the access information is notified to the client terminal, a connection request from the client terminal based on the access information is accepted, and the connection control device corresponding to the address information receives the client Connecting terminals via relay,
It is characterized by that.

Specifically, the relay server connected between the client terminal and the connection control device is a connection control method for connecting and relaying the client terminal to the connection control device,
A connection establishment step of selecting one of the connection control devices when receiving a communication establishment request from the client terminal, and establishing a connection to the selected connection control device;
An address notification step of notifying the client terminal of address information for connecting to the selected connection control device;
A relay connection step of accepting a connection request based on address information from the client terminal and relay-connecting the client terminal to the connection control device corresponding to the address information;
It is characterized by having.

  And the connection establishment process selects one said connection control apparatus according to the operating condition of a connection control apparatus, It is characterized by the above-mentioned.

In addition, before the connection establishment step, there is a monitoring step of communicating with the connection control device to monitor the operation status of the connection control device, and storing the operation status in the connection control device information storage means,
The connection establishing step is characterized in that one connection control device is selected based on information in the connection control device information storage means.

  As described above, even when the system, program, and method are configured as described above, the above-described object of the present invention can be achieved because the system has the same operation as the relay server.

  Since the present invention is configured and functions as described above, according to this, a connection control device for performing connection control is assigned to each client terminal in the relay computer, and the address of the connection control device notified at this time is assigned. After that, since the connection request is made from the client terminal, connection control is performed by the same connection control device for each client terminal while distributing the load of the connection control processing, so that the connection can be stabilized. It is possible to achieve a highly reliable connection control process, and has an unprecedented excellent effect.

  The present invention adopts a configuration for realizing load distribution and risk distribution of a call control server using a protocol such as SIP used in an IP telephone service without using a load distribution apparatus. Hereinafter, a configuration in which call control is performed in response to a call request from a client terminal using a call control device in a mobile system will be described as an example. However, the present invention is not limited to being used in a mobile system, and may of course be used in an IP telephone system. Further, the present invention is not limited to a call processing device using SIP, and can be used when load distribution is performed in another application server such as a Web system using an HTTP protocol.

  A first embodiment of the present invention will be described with reference to FIGS. 1 to 2 are diagrams showing a system configuration, and FIGS. 3 to 6 are diagrams showing an operation of the system.

[Constitution]
FIG. 1 shows a configuration when a call control device 3 that realizes multimedia services such as an IP telephone is applied to a land mobile network 2. First, the overall configuration will be described.

  The land mobile network 2 is an infrastructure of a general mobile phone network, and includes a wireless network and a core network that performs circuit switching and packet transfer. The client terminal 1 connected to the land mobile network 2 is a portable information processing terminal such as a general user's mobile phone. The gateway device 5 is one of the components of the mobile network 2 and relays between the call control device 3 that performs call processing of multimedia services such as IP telephones and the client terminal 1 via the network. Connected and provided.

  Here, there is SIP or the like as a signal protocol used in the call control device 3 system. For example, SIP is a signaling protocol that is being standardized by the IETF. SIP: Session Initiation Protocol ", RFC3261, June 2002." With this SIP protocol, the call control device 3 performs functions such as user authentication, registration of location information such as an address, and call processing.

  The subscriber data devices 41 and 42 (location server, mirror server) are database servers that hold subscriber information, such as user IDs, telephone numbers, authentication information for accessing the network, and subscribed service information. I manage. In particular, it manages location registration information (location registration information) of the client terminal 1 and subscriber information necessary for making a call. The subscriber data devices 41 and 42 are separated from the call control device 3. However, since the subscriber data devices 41 and 42 are connected to the respective call control devices 3 through dedicated interfaces and can refer to the subscriber information, the gateway device 5 can determine which call control device. Even if a registration request message is sent to the user, services such as location registration and telephone call are possible. In other words, the system comprising the call control device 3 and the subscriber data devices 41 and 42 is dispersed in the region, but since the registration request message from the client can be relayed to a different gateway device 5 by another route, The service can be continued even if it goes down due to a disaster. The subscriber data devices 41 and 42 are divided into a main system 41 (location server) and a sub system 42 (mirror server). On the other hand, even if a failure occurs, a communication failure with the operating system (main system) 41 is detected. Thus, the redundant configuration is adopted so that the switching to the standby system (secondary system) 42 can be performed instantaneously.

  Next, the configuration of the gateway device 5 (relay server) described above will be described with reference to FIGS. The gateway device 5 is a general server computer having an arithmetic device such as a CPU and a storage device such as a hard disk. As shown in FIG. 2, a state monitoring unit 51, a call control device selection unit 52, and a packet transfer unit 53 are constructed by incorporating a predetermined program in the arithmetic device. Further, a call control device list storage unit 54 is formed in the storage device. The details will be described below.

  First, the state monitoring unit 51 (monitoring means) performs a health check using a continuity signal with the call control device 3 that is regularly connected to detect a failure (see (A1) in FIG. 3). Furthermore, a congestion state, that is, a load state due to call control processing is detected from the state notification signal transmitted from the call control device 3 (see (A2) in FIG. 3). Then, the detected failure or congestion state is notified to the call control device selection unit 52. At this time, for example, when a health check signal is not returned, it is detected as a failure state, and when the state notification signal is in a load state exceeding a preset value, it is detected as a congestion state. Then, the call control device selection unit 52 is notified of information specifying the call control device 3.

  The call control device selection unit 52 first manages the detected failure or congestion state of the call control device 3 described above, that is, performs list management of selectable call control devices 3. For example, when a failure or congestion is detected by the state monitoring unit 51, the call control device 3 in the failure or congestion state is excluded from selection targets and the call in the call control device list storage unit 54 (connection control device information storage means) The list of the control device 3 is rewritten (see (A3) in FIG. 3).

  When the call control device selection unit 52 receives a packet communication establishment request from the client terminal 1 (see (B1) in FIG. 4), as described above, the call control device 3 in a failure or congestion state is selected. One arbitrary call control device 3 is selected from the list in the call control device list storage unit 54 in the state removed from the list. Then, a connection path is established with the selected call control device 3 (see (B2) in FIG. 4). At this time, a connection request signal is transmitted from the call control selection unit 52 to the call control device 3 to notify user terminal information and the like. When a connection response is returned from the call control device 3 and a connection path is established (see (B3) in FIG. 4), the call control device selection unit 52 sends the selected call control device 3 to the client terminal 1. An IP address (address information) that is information for access is notified (see (B4) in FIG. 4). In this way, the call control device selection unit 52 selects one of the connection control devices when receiving a communication establishment request from the client terminal 1, and establishes a connection to the selected connection control device. And the address notification means for notifying the client terminal 1 of the address information for connecting to the selected connection control device 3.

  The call control device selection unit 52 described above selects one based on the call control device list in which the state of the call control device 3 detected by the state monitoring unit 51 is accumulated. The operation state (failure, load state, etc.) of the call control device 3 may be detected in response to a connection request from the terminal, and selection may be made based on the detection state. Also at this time, the call control device 3 that is of course broken or has a high load (congestion state) is excluded from the selection targets and selected.

  Further, the packet transfer unit 53 (relay connection means) transfers the SIP signal registration request transmitted from the client terminal 1 (see (B5) in FIG. 4) to the call control device 3 by IP routing (in FIG. 4). (See (B6)). That is, the client terminal 1 and the call control device 3 are relay-connected. Note that the packet transfer unit 53 operates to make a relay connection to the addressed call control device 3 in the same manner as described above even when a subsequent call request is issued from the client terminal 1.

[Operation]
Next, the operation of the present invention will be described with reference to FIGS. First, call control is carried out using the SIP protocol in the above system, but the SIP protocol sends a message (INVITE signal) of a call request from one client as a pre-procedure for starting an IP phone. However, it is necessary to exchange SIP call control signals with the other client several times. This SIP message is relayed by the call control device 3 in FIG. Since the call control device 3 relays the SIP message and needs to know location information such as the IP address of the called client, the client sends a SIP registration request message (REGISTER signal) to the call control server in advance prior to the telephone service. ) To register location information. The subscriber data unit 4 holds authentication information for this purpose. In the present embodiment, an operation when performing SIP registration processing (location registration request) will be described. In the SIP registration processing, the gateway device 5 selects a call control device for each user, so that the processing can be distributed and load concentration can be prevented.

  First, with reference to a functional block diagram of the gateway device 5 shown in FIG. 3 and a flowchart of FIG. First, the state monitoring unit 51 in the gateway device 5 performs state monitoring such as failure or congestion (step S1 in FIG. 5, monitoring step). Then, the state monitoring unit 51 periodically transmits a health check signal to the call control device 3 to confirm continuity (step S2 in FIG. 5, (A1) in FIG. 3). At this time, if a continuity confirmation signal does not come from the call control server, it is determined that the server or communication path is faulty and a fault is detected (step S3 in FIG. 5).

  Further, when the call control device 3 becomes overloaded due to a congestion level exceeding a certain threshold, a state notification signal indicating the congestion state is transmitted to the gateway device 5, and thus the gateway device 5 (Step S4 in FIG. 5, (A2) in FIG. 3). Thereby, it is detected that the specific call control device 3 is in a congested state (step S5 in FIG. 5). Once a failure or congestion state is detected by the state monitoring unit 51, status information is held until the next return to normal state is notified.

  Here, the call control device selection unit 52 manages a list of call control devices 3 that are transmission destinations of call control signals. Therefore, when a failure or congestion is detected in steps S3 and S5 and it is found that the device is temporarily unavailable, the call control device selection unit 52 excludes the corresponding device from the selection destination list (steps S6 and S6 in FIG. 5). (A3) of FIG. That is, the gateway device 5 can detect a failure or congestion in the call control device 3 and dynamically perform load distribution as described later.

  Next, the operation at the time of relay connection of the call control device 3 will be described with reference to the functional block diagram of the gateway device 5 shown in FIG. 4 and the flowchart of FIG. When the client terminal 1 transmits a packet communication establishment request signal to the gateway device 5 ((B1) in FIG. 4) in order to establish the transmission path of the IP packet after establishing the wireless link, the gateway device 5 Received (step S11 in FIG. 6). Then, the call control device selection unit 52 excludes the list of the call control devices 3 that are the transmission destinations of the clients, that is, the call control devices 3 from which the failure or congestion has been detected by step S6 in FIG. Any one call control device 3 is selected from the list (step S12 in FIG. 6). Here, there are some typical selection logics such as round robin. The call control device selection unit 52 transmits a connection request to the arbitrarily selected call control device 3 ((B2) in FIG. 4), and establishes a path between the gateway device 5 and the call control device 3. The client information is notified to the call control device 3 (step S13 in FIG. 6, connection establishment step). The client information includes terminal information unique to the client or an IP address.

  When a connection response is returned from the call control device 3 ((B3) in FIG. 4) and a connection path is established between the gateway device 5 and the call control device 3 (Yes in step S14 in FIG. 6), the call control device. The selection unit 52 finally notifies the client of the IP address of the call control device 3 (step S15 in FIG. 6, (B4) in FIG. 4, address notification step). Thereafter, when the client transmits a SIP registration request message to the IP address ((B5) in FIG. 4), IP routing is performed to the call control device by the packet transfer unit 53 of the gateway device (step S16 in FIG. 6). 4 (B6), relay connection step). Here, the call control device 3 confirms from the client information acquired in step S13 of FIG. 6 whether the request source of the received SIP signal is permitted by establishing a connection path with the gateway device ( Step S17 in FIG. As a result, even if the registration request is randomly transmitted by the terminal, it plays a role of blocking in advance.

  To summarize the above operations, first, when the gateway device 5 which is a component of the mobile network 2 receives a packet communication establishment request from the client terminal 1, between the gateway device 5 and the specific call control device 3. In order to establish a connection path, one is arbitrarily selected from a plurality of call control devices. When the path from the gateway device 5 to the call control device 3 is determined by establishing the connection path, the gateway device 5 notifies the client terminal 1 of the IP address of the call control device 3. Thereafter, the client terminal 1 transmits a SIP packet serving as an actual call processing signal to the notified IP address of the call control server. As a result, the call control device 3 is assigned to each user with respect to the SIP signal from the terminal, so that load distribution is possible.

  As described above, by distributing the connection destinations by the gateway device 5, and further, by detecting a failure or a congestion detection device that has become unusable from the service target in advance, a load balancer, etc. A reliable and stable load balance can be performed without using the. Furthermore, it is possible to disperse the dangers as a countermeasure against fierceness by securing a plurality of routes to the gateway device.

  Here, the case where the gateway device 5 selects one call control device 3 has been exemplified above, but at least one may be selected, and one client terminal 1 can be selected from a failure state or a congestion state. A plurality of call control devices 3 that can be connected may be selected.

  The present invention can be used for load distribution in an IP telephone system using a call control device based on the SIP protocol, a mobile system, and the like, and has industrial applicability.

1 is a block diagram illustrating an overall configuration of a mobile system in Embodiment 1. FIG. It is a functional block diagram which shows the structure of the gateway apparatus disclosed in FIG. It is a figure explaining operation | movement of the gateway apparatus disclosed in FIG. 1, and shows the operation | movement at the time of the state monitoring of a call control apparatus. It is a figure explaining operation | movement of the gateway apparatus disclosed in FIG. 1, and shows the operation | movement at the time of the connection request | requirement from a client terminal to a call control apparatus. It is a flowchart explaining operation | movement of the gateway apparatus disclosed in FIG. 1, and shows the operation | movement at the time of the state monitoring of a call control apparatus. 2 is a flowchart for explaining the operation of the gateway device disclosed in FIG. 1, and shows the operation when a connection request is made from the client terminal to the call control device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Client terminal 2 Mobile communication network 3 Call control apparatus 5 Gateway apparatus 41 Subscriber data apparatus (main system)
42 Subscriber data device (secondary)
51 Status Monitoring Unit 52 Call Control Device Selection Unit 53 Packet Transfer Unit 54 Call Control Device List Storage Unit

Claims (16)

A computer connected to the client terminal and the connection control device,
Select at least one connection control device in response to access from the client terminal, notify the client terminal of access information to the connection control device, and accept a connection request from the client terminal based on the access information Having the function of relay connecting the client terminal to the connection control device corresponding to the access information,
A computer characterized by that. A relay server connected between the client terminal and the connection control device,
Connection establishment means for selecting one of the connection control devices when receiving a communication establishment request from the client terminal, and establishing a connection to the selected connection control device;
Address notification means for notifying the client terminal of address information for connecting to the selected connection control device;
Relay connection means for accepting a connection request based on the address information from the client terminal and relay-connecting the client terminal to the connection control device corresponding to the address information;
A relay server comprising:   The relay server according to claim 2, wherein the connection establishment unit selects one of the connection control devices according to an operation status of the connection control device.   The relay server according to claim 3, wherein the connection establishing unit selects one of the connection control devices according to whether the connection control device is normal or malfunctioning.   5. The relay server according to claim 3, wherein the connection establishment unit selects one of the connection control devices according to a load status of the connection control device. Connection control device information storage means;
Monitoring means for communicating with the connection control device to monitor the operation status of the connection control device, and storing the operation status in the connection control device information storage means,
The connection establishment means selects one of the connection control devices based on information in the connection control device information storage means;
The relay server according to claim 3, 4 or 5.   7. The relay server according to claim 2, wherein the connection relay unit receives a location registration request from the client terminal as the connection request. The relay server according to claim 2 or 7 and the connection control device,
The connection control device performs call control of another client terminal in response to a request from the client terminal relay-connected by the relay server;
A call control system. A location server for storing location registration information of the client terminal which is a mobile terminal;
The information in the location server is information that can be referred to during call control by the connection control device from a plurality of the connection control devices.
9. The call control system according to claim 8, wherein:   The call control system according to claim 9, further comprising a mirror server that stores the same information as the information in the location server and can be referred to by the plurality of connection control devices. To the relay server connected between the client terminal and the connection control device,
Connection establishment means for selecting one of the connection control devices when receiving a communication establishment request from the client terminal, and establishing a connection to the selected connection control device;
Address notification means for notifying the client terminal of address information for connecting to the selected connection control device;
Relay connection means for receiving a connection request based on the address information from the client terminal and relay-connecting the client terminal to the connection control device corresponding to the address information;
A program to realize Monitoring means for communicating with the connection control device to monitor the operation status of the connection control device, and storing the operation status in the connection control device information storage means;
The connection establishment means operable to select one of the connection control devices based on information in the connection control device information storage means;
The program of Claim 11 for implement | achieving. A computer connected to a client terminal and a connection control device is a connection control method in which the client terminal is relay-connected to the connection control device,
According to the access from the client terminal, at least one connection control device is selected, the access information is notified to the client terminal, a connection request from the client terminal based on the access information is received, and the address information is Relay connecting the client terminal to the corresponding connection control device;
A connection control method characterized by the above. A relay server connected between a client terminal and a connection control device is a connection control method for connecting and relaying the client terminal to the connection control device,
A connection establishment step of selecting one of the connection control devices when receiving a communication establishment request from the client terminal, and establishing a connection to the selected connection control device;
An address notification step of notifying the client terminal of address information for connecting to the selected connection control device;
A relay connection step of accepting a connection request based on the address information from the client terminal and relay-connecting the client terminal to the connection control device corresponding to the address information;
A connection control method characterized by comprising:   The connection control method according to claim 14, wherein in the connection establishment step, one connection control device is selected according to an operating state of the connection control device. Prior to the connection establishment step, there is a monitoring step of communicating with the connection control device to monitor the operation status of the connection control device and storing the operation status in the connection control device information storage means,
The connection establishment step selects one of the connection control devices based on information in the connection control device information storage means.
The connection control method according to claim 15.

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