Patent Publication Number: US-2013246600-A1

Title: Communication service providing system, method of providing communication service and data center management system

Description:
TECHNICAL FIELD 
     The present invention relates to a communication service providing system which provides a service via a network from a data center, a method of providing communication service therefor, and a data center management system and a data center management program which are applied to the communication service providing system, and particularly to a communication service providing system capable of providing services with the same level of communication quality independently of a user&#39;s location, a method of providing communication service therefor, and a data center management system and a data center management program which are applied to the communication service providing system. 
     BACKGROUND ART 
     In recent years, services provided to a user via a network from a data center increases. It also rapidly increases users of such services. A data center which provides services to users via a network and a server or the like in the data center is referred to as a cloud. 
     In this service providing mode, a plurality of data centers are provided in order to provide services while defining a storage area for an individual user which the user is able to use in a storage in the data center and storing user data in the storage area. This storage area is called a use area or a user area. The content of the service to be provided is not particularly limited and the content of the user data depends on the type of service. 
     A user is able to receive a desired service by performing processing according to the service while a user&#39;s terminal device and a data center (more specifically, a server in the data center) send and receive information. 
     In addition, a network between the user&#39;s terminal device and the data center is called an access network. Networks to be access networks are provided by various communication carriers. A network (access network) is provided for a communication carrier and the quality of service (QoS) depends on the network. Further, Patent Literature (PTL)  1  describes an application program move position decision method of deciding an appropriate destination for an application program or a data file according to a user&#39;s location on the network. 
     CITATION LIST 
     Patent Literature(s) 
     
         
         PTL 1: Japanese Patent Application Laid-Open No. 11 (1999)-143836 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     Although the user area of an individual user is provided in the storage in the data center as described above, the user cannot recognize in which data center his/her own user area is provided and from which data center the user receives the service. Further, if the physical distance between the user&#39;s terminal and the data center which ensures the user area of the user and provides the service to the user is too long, access time from the user&#39;s terminal to the data center increases or the throughput decreases, thereby reducing the user experience at the time of using the service. 
       FIG. 15  is an explanatory diagram schematically illustrating the physical distance between the user&#39;s terminal and data centers. A data center group  81  including data centers  82   a  to  82   c  and the like is managed by the same cloud service provider. The data centers  82   a  to  82   c  are arranged in regions different from each other. In the example illustrated in  FIG. 15 , the data center  82   a , the data center  82   b , and the data center  82   c  are arranged in a region A, a region B, and a region C, respectively. The data center  82   a  includes a storage  83   a , a server  84   a , and network equipment  85   a . Hereinafter, the network is sometimes referred to as simply NW. The storage  83   a  is a storage device to which a user area is allocated, and user data is stored in the user area. The server  84   a  is an information processor which provides a service by communicating with a user&#39;s terminal  87 . The network equipment  85   a  is an interface with a network in the data center  82   a . Similarly, the data center  82   b  includes a storage  83   b , a server  84   b , and network equipment  85   b . The data center  82   c  also includes a storage  83   c , a server  84   c , and network equipment  85   c.    
     Further, in  FIG. 15 , there are illustrated networks  91   a  to  91   e  as access networks. In this example, the individual networks  91   a  to  91   e  are networks for communication carriers A, B, C, D, and E different from each other. The qualities of service of the networks  91   a  to  91   e  are different from each other, too. Moreover, a network utility rate for performing communication depends on each network. 
     Further, it is assumed that the user area of the user using the terminal  87  is provided in the storage  83   a  in the data center  82   a  and the user receives a service from the server  84   a . If the user&#39;s terminal  87  exists in the region A, an access path from the terminal  87  to the data center  82   a  is short, and therefore the communication delay time is expected to be short when the user enjoys the service on the data center  82   a  by using the terminal  87 . On the other hand, it is assumed that the user and the terminal  87  have moved from the region A, where the data center  82   a  is arranged, to a region C, which is distant from the region A. Then, the access path from the terminal  87  to the data center  82   a  is a relatively long path. It is expected that the increase in the path increases the delay time when accessing from the terminal  87  to the data center  82   a.    
     Specifically, if the same user attempts to receive the same service from the data center  82   a , there is a difference in the communication delay time when attempting to receive the service, depending on which region the user exists in. This means that the communication quality of service changes according to the user&#39;s location 
     Moreover, although PTL 1 describes a method for deciding the appropriate destination, such as an application program in accordance with the user&#39;s location, unless the application program, data files, and the like are actually moved, it is impossible to solve the above problem that the communication quality of service changes according to the user&#39;s location. In other words, the above problem cannot be solved by simply deciding the destination. 
     In addition, the services provided by the data centers  82   a  to  82   c  are not limited to one type and the data centers  82   a  to  82   c  provide various services. Further, for example, whether to use only a narrow bandwidth or to use a wide bandwidth, whether to allow delay to a certain degree or preferably to minimize the delay, and the like depend on the type of service. Specifically, there is a difference in the quality of service requested to the network depending on the type of service. On the other hand, if the user&#39;s terminal  87  accesses a network of a certain communication carrier and starts the use of the service of the data center via the network, the user has not been able to receive the same service only via the first accessed network unless the user intentionally operates the terminal  87  to change the network, Therefore, unless the quality of the network required for the service which the user wants to use matches the quality of the network which the user accessed (e.g., if the network delay time is too large or if the amount of bandwidth is too small), it has been required to change the network that the user accesses by intentionally performing the operation. 
     Therefore, it is an object of the present invention to provide a communication service providing system capable of providing the same level of services independently of a location where a user&#39;s terminal exists and providing services to a user via a network appropriate to the service, a method of providing communication service therefor, and a data center management system and a data center management program which are applied to the communication service providing system. 
     Solution to Problem 
     A communication service providing system according to the present invention includes: a plurality of data centers which provide services to a user by communicating with a terminal of the user; and a data center management system which manages the respective data centers, wherein: each data center, when providing the service to the user, secures a user area which is a storage area for the user for use in providing the service and stores user data which is data for the user for use in providing the service into the user area; and the data center management system includes: location information collection means for collecting location information on the terminal of the user receiving the service from any one of the data centers; user data and the like transfer instruction means for determining a data center closest to a location indicated by the location information and, in the case where the data center differs from the data center currently providing the service to the user, instructing the data center currently providing the service to the user to transfer the user data and the user area of the user to the data center closest to the location indicated by the location information; service type and the like collection means for collecting information on the type of service provided to the user and the type of network used for providing the service to the user from the respective data centers; and network switching control means for determining the type of network appropriate to the type of service provided to the user by the data center and, in the case where the type of network does not match the information on the type of network collected by the service type and the like collection means, performing control to switch the network used for providing the service to the user to the network appropriate to the type of service. 
     A data center management system according to the present invention manages a plurality of data centers which provide services to a user by communicating with a terminal of the user, secures a user area which is a storage area for the user for use in providing the services when providing the services to the user, and stores user data which is data for the user for use in providing the services into the user area, and the center management system includes: location information collection means for collecting location information on the terminal of the user receiving the service from any one of the data centers; user data and the like transfer instruction means for determining a data center closest to a location indicated by the location information and, in the case where the data center differs from the data center currently providing the service to the user, instructing the data center currently providing the service to the user to transfer the user data and the user area of the user to the data center closest to the location indicated by the location information; service type and the like collection means for collecting information on the type of service provided to the user and the type of network used for providing the service to the user from the respective data centers; and network switching control means for determining the type of network appropriate to the type of service provided to the user by the data center and, in the case where the type of network does not match the information on the type of network collected by the service type and the like collection means, performing control to switch the network used for providing the service to the user to the network appropriate to the type of service. 
     A method of providing communication service is characterized by that: a plurality of data centers provide services to a user by communicating with a terminal of the user; when providing the service to the user, each data center secures a user area which is a storage area for the user for use in providing the service and stores user data which is data for the user for use in providing the service into the user area; and a data center management system which manages the respective data centers performs the operations of: collecting location information on the terminal of the user receiving the service from any one of the data centers; determining a data center closest to a location indicated by the location information and, in the case where the data center differs from the data center currently providing the service to the user, instructing the data center currently providing the service to the user to transfer the user data and the user area of the user to the data center closest to the location indicated by the location information; collecting information on the type of service provided to the user and the type of network used for providing the service to the user from the respective data centers; and determining the type of network appropriate to the type of service provided to the user by the data center and, in the case where the type of network does not match the collected information on the type of network, performing control to switch the network used for providing the service to the user to the network appropriate to the type of service. 
     A data center management program according to the present invention is installed on a computer which manages a plurality of data centers each of which provides a service to a user by communicating with a terminal of the user and, when providing the service to the user, secures a user area which is a storage area for the user for use in providing the service, and then stores user data which is data for the user for use in providing the service into the user area, and the data center management program causes the computer to perform: a location information collection process of collecting location information on the terminal of the user receiving the service from any one of the data centers; a user data and the like transfer instruction process of determining a data center closest to a location indicated by the location information and, in the case where the data center differs from the data center currently providing the service to the user, instructing the data center currently providing the service to the user to transfer the user data and the user area of the user to the data center closest to the location indicated by the location information; a service type and the like collection process of collecting information on the type of service provided to the user and the type of network used for providing the service to the user from the respective data centers; and a network switching control process of determining the type of network appropriate to the type of service provided to the user by the data center and, in the case where the type of network does not match the information on the type of network collected in the service type and the like collection process, performing control to switch the network used for providing the service to the user to the network appropriate to the type of service. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to provide the same level of services independently of the location where a user&#39;s terminal exists and to provide services to a user via a network appropriate to the service. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating a configuration example of a communication service providing system of the present invention. 
         FIG. 2  is a block diagram illustrating a configuration example of a data center management system  1 . 
         FIG. 3  is a conceptual diagram of the operation of a communication service providing system according to the present invention. 
         FIG. 4  is a flowchart illustrating an example of a processing progress of the data center management system  1  for a transfer of a user area and the like in a first method. 
         FIG. 5  is an explanatory diagram illustrating exchanges of an instruction and the like between the data center management system, data centers, a location information server, and a subscription server in the first method. 
         FIG. 6  is a flowchart illustrating an example of a processing progress of the data center management system  1  for a transfer of a user area and the like in a second method. 
         FIG. 7  is an explanatory diagram illustrating exchanges of an instruction and the like between the data center management system, the data centers, the location information server, and the subscription server in the second method. 
         FIG. 8  is a conceptual diagram of a switching operation of a network appropriate to a service type. 
         FIG. 9  is a flowchart illustrating an example of a processing progress of the data center management system  1  for network switching. 
         FIG. 10  is an explanatory diagram illustrating exchanges of an instruction and the like between the data center management system, the data centers, and NW controllers in a network switching process. 
         FIG. 11  is an explanatory diagram illustrating an optimization target range  71  for the access network switching in a protocol stack. 
         FIG. 12  is an explanatory diagram illustrating an optimization target range  81  in a protocol stack in the case of performing network switching by using data centers and a terminal 
         FIG. 13  is a block diagram illustrating a minimum configuration example of the communication service providing system of the present invention. 
         FIG. 14  is a block diagram illustrating a minimum configuration example of the data center management system of the present invention. 
         FIG. 15  is an explanatory diagram schematically illustrating a physical distance between a user&#39;s terminal and data centers. 
     
    
    
     DESCRIPTION OF EMBODIMENT(S) 
     Hereinafter, exemplary embodiments of the present invention will be described with reference to accompanying drawings. 
       FIG. 1  is a block diagram illustrating a configuration example of a communication service providing system of the present invention. A communication service providing system  10  according to the present invention includes a plurality of data centers  11   a  to  11   c  and a data center management system  1 . Although  FIG. 1  illustrates three data centers  11   a  to  11   c , the number of data centers is not limited to three and may be two or greater than three. 
     In the example illustrated in  FIG. 1 , the data centers  11   a  to  11   c  are arranged in regions different from each other. In this example, the data center  11   a , the data center  11   b , and the data center  11   c  are arranged in a region A, a region B, and a region C, respectively. 
     Each data center includes a storage, a server, and NW equipment (network equipment). Describing the data center  11   a  as an example, the data center  11   a  includes a storage  12   a , a server  13   a , and NW equipment  14   a.    
     The server  13   a  communicates with a user&#39;s terminal  17  to perform processing of providing services to the user of the terminal  17 . The type of service is not particularly limited, and the server  13   a  may perform processing according to a service. Although  FIG. 1  illustrates only the terminal  17  as a user&#39;s terminal, a plurality of users exist and a plurality of user&#39;s terminals exist, too. In the following description, the terminal  17  is taken as an example of a user&#39;s terminal. 
     The storage  12   a  is a storage device which secures a user area of the user who receives a service provided by the server  13   a . The user area of one user stores data which is used to receive a service provided to the user (user data) and information representing the type of service provided to the user by the server  13   a . The content of the user data depends on the type of service to be provided. 
     The NW equipment  14   a  is an interface with a network in the data center  11   a . The server  13   a  communicates with the user&#39;s terminal  17  via various networks by using the network equipment  14   a  to perform processing according to a service. 
     The data center management system  1  manages the respective data centers  11   a  to  11   c . Specifically, the data center management system  1  collects location information on the user&#39;s terminal  17  from the networks of communication carriers and determines whether the user area of the user of the terminal  17  is secured in an appropriate data center in accordance with the location information on the terminal  17 . Unless the user area of the user is secured in the appropriate data center, the data center management system  1  controls the data center to transfer the user area to the appropriate data center. 
     Moreover, the data center management system  1  selects a network according to the service provided to the user by the data center and controls the data center to communicate with the user&#39;s terminal  17  via the network. 
       FIG. 1  illustrates networks  21   a  to  21   e  as access networks (networks) for the user&#39;s terminal  17  to access data centers. Individual networks  21   a  to  21   e  are, for example, networks for communication carriers different from each other. In the example illustrated n  FIG. 1 , the network  21   a  is a network for a communication carrier A. Similarly, networks  21   b ,  21   c ,  21   d , and  21   e  are networks for communication carriers B, C, D, and E, respectively. 
     The QoS (for example, a delay time or a communication band) differs for each network. Moreover, the network utility rate for performing communication differs for each network. 
     Moreover, a mobile carrier has a location information server which monitors the location information on the terminal (i.e., mobile terminal) of a user contracting with the communication carrier and retains the location information. The location information server updates the retained location information in the case where the terminal has moved. In the example illustrated in  FIG. 1 , communication carriers A, C, and E are mobile carriers and location information servers  22   a ,  22   c , and  22   e  are arranged in the networks  21   a ,  21   c , and  22   e . The data center management system  1  collects location information on the terminals of users from the respective location information servers  22   a ,  22   c , and  22   e.    
     Moreover, a communication carrier of a fixed terminal (hereinafter, referred to as the fixed carrier) has a subscription information server which retains subscription information on each user who has a subscription contract with the fixed carrier. In the example illustrated in  FIG. 1 , the communication carriers B and D are fixed carriers and the subscription information servers  22   b  and  22   d  are arranged in the networks  21   b  and  21   d . The subscription information for each user retained in each of the subscription information servers  22   b  and  22   d  contains information on the line installation location of the fixed terminal of the user who has a subscription contract (for example, information on the area where the fixed terminal is installed such as a user&#39;s address). Therefore, the subscription information also contains the location information on the user&#39;s terminal (the fixed terminal, here). The data center management system  1  collects location information on the terminal (fixed terminal) contained in the subscription information by collecting the subscription information from the respective subscription information servers  22   b  and  22   d.    
     The subscription information servers  22   b  and  22   d  play the same roles as the location information servers  22   a ,  22   c , and  22   e  in terms of sending the location information on the terminal to the data center management system  1 . Therefore, both of the location information server and the subscription information server are able to be referred to as “terminal location information providing devices” which send location information on the respective terminals to the data center management system  1 . 
     Moreover, each communication carrier has a network controller (not illustrated in  FIG. 1  and hereinafter referred to as the NW controller) in the network of the communication carrier. For example, the communication carrier A has an NW controller in the network  21   a  and the communication carrier B has an NW controller in the network  21   b . The same applies to other communication carriers C to E. The NW controller is a device which changes a network used for a communication between the terminal  17  and the data center in communication. The NW controller switches the network (access network) without changing, for example, an IP address allocated to the user&#39;s terminal  17 . This network switching process is able to be performed by a method described, for example, in “3GPP TS23.401” which is able to be referenced in the following reference literature 1 or “3GPP TS23.402” which is able to be referenced in the following reference literature 2. 
     [Reference Literature 1] 
     
         
         “3GPP Specification detail,” [Retrieved on Nov. 30, 2010], retrieved from the Internet: http://www.3gpp.org/ftp/specs/html-info/23401.htm 
       
    
     [Reference Literature 2] 
     
         
         “3GPP Specification detail,” [Retrieved on Nov. 30, 2010], retrieved from the Internet: http://www.3gpp.org/ftp/specs/html-info/23402.htm 
       
    
       FIG. 2  is a block diagram illustrating a configuration example of the data center management system  1 . The data center management system  1  includes data center configuration management means  31 , user location and data center arrangement optimization means  32 , service type and network optimization means  33 , user location management means  34 , data center communication means  35 , and carrier system communication means  36 . 
     The data center communication means  35  is a communication interface with data centers for performing communication with the data centers  11   a  to  11   c  conducted by a cloud service provider. 
     The data center configuration management means  31  communicates with the data centers via the data center communication means  35  to collect usage and operating conditions of the data centers and manages the collected data. For example, in addition to the system capacity of each data center, the data center configuration management means  31  collects and stores information on the capacity of the use area (user area) used by each user, the user data capacity, the CPU occupancy rates of devices in the data center, the type of service provided to the user by the data center, the user&#39;s usage condition of the service (which service the user is using), and the like from each data center. 
     The carrier system communication means  36  is a communication interface for communicating with devices (location information servers  22   a ,  22   c , and  22   e , subscription information servers  22   b  and  22   d , NW controllers  23   a  and  23   b , and the like) in the network of each communication carrier. 
     The user location management means  34  collects user location information (specifically, the location information on a user&#39;s terminal) via the carrier system communication means  36 . For example, the user location management means  34  collects location information on the user&#39;s terminal (mobile terminal) from the location information servers  22   a ,  22   b , and  22   c  in the network of the mobile carrier. Moreover, for example, the user location management means  34  collects information on the line installation location of a user&#39;s fixed terminal (for example, information on the installation area of the fixed terminal) by collecting the subscription information from the subscription information servers  21   d  and  22   d  of the fixed carrier. Specifically, the user location management means  34  collects the location information on the fixed terminal. 
     Further, the user location management means  34  stores the location information on the user&#39;s terminal in addition to the information on the network of the communication carrier used for an access to the data center by the user (information on the network [access network] in communication). The information on the network in communication may be collected from the data center, for example, by the data center configuration management means  31 . The location information on the user&#39;s terminal stored in this manner is able to be referred to as a user location database (user location DB). In the case of a change in the location information on the user&#39;s terminal, the user location management means  34  updates the location information stored therein. Moreover, information on a network is, for example, information on the communication system of a communication carrier. Specifically, it is information on whether the network communication system is 2G, 3G, or long-term evolution (LTE), information on whether the worldwide interoperability for microwave access (WiMAX) is used, or the like. The type of network communication system as described above determines the communication quality, the service level, the utility rate of the network (access network) used by the user, and the like. 
     The user location and data center arrangement optimization means  32  determines whether or not the user receives a service from the appropriate data center on the basis of the information collected by the data center configuration management means  31  and the location information on the user&#39;s terminal collected by the user location management means  34 . When determining that the user does not receive the service from the appropriate data center, the user location and data center arrangement optimization means  32  instructs the data center to transfer the user area and the user data from the data center currently providing the service to the appropriate data center. 
     The data center configuration management means  31  manages information on the type of service used by the user. The user location management means  34  manages information on the network in communication used by the user. The service type and network optimization means  33  decides an access network (network) appropriate to the service being used by the user on the basis of the above information. In this decision, the service type and network optimization means  33  selects a network enabling the user&#39;s terminal to maintain a session in communication with the data center. The service type and network optimization means  33  instructs the NW controller of the network used by the user to change the network for the user to communicate with the data center via the carrier system communication means  36 . 
     The data center configuration management means  31 , the user location and data center arrangement optimization means  32 , the service type and network optimization means  33 , the user location management means  34 , the data center communication means  35 , and the carrier system communication means  36  are implemented by, for example, a computer which includes a memory and operates according to a program. Specifically, the computer may read a data center management program to operate as the data center configuration management means  31 , the user location and data center arrangement optimization means  32 , the service type and network optimization means  33 , the user location management means  34 , the data center communication means  35 , and the carrier system communication means  36  according to the program. Moreover, the data center configuration management means  31 , the user location and data center arrangement optimization means  32 , the service type and network optimization means  33 , the user location management means  34 , the data center communication means  35 , and the carrier system communication means  36  may be implemented by units separate from each other. 
       FIG. 3  is a conceptual diagram of the operation of a communication service providing system according to the present invention. If the user and the terminal  17  thereof exist in the region A, the data center  11   a  in the region A secures user data and a user area  51  for the user and provides a service to the user by communicating with the terminal  17 . 
     It is assumed that the user moves and receives a service by using the terminal  17  existing in the region C. Although the terminal  17  also moves along with the user in this example here, the user having moved may use a fixed terminal in the region C in another mode. In the case where the user receives a service in the region C in this manner, the data center management system  1  transfers the user data and the user area  51  having been secured in the data center  11   a  to the data center  11   c.    
     As a method of transferring user data and a user area to another data center in this manner, there are a data-center-driven method and a carrier-driven method. Hereinafter, the former is referred to as the first method and the latter is referred to as the second method. 
       FIG. 4  is a flowchart illustrating an example of a processing progress of the data center management system  1  for a transfer of a user area and the like in the first method. As described later, the data center configuration management means  31  of the data center management system  1  constantly monitors the data centers  11   a  to  11   c  to collect the usage and operating conditions of the data centers. 
     Then, the user location management means  34  determines the user&#39;s terminal which receives the service from the data center on the basis of the usage and operating conditions of the data centers and determines whether or not the location information on the terminal is collected (step S 1 ). If the location information on the terminal of the user receiving the service from the data center has already been collected (Yes in step S 1 ), the control proceeds to step S 3 . If the location information on the terminal of the user receiving the service from the data center has not been collected yet (No in step S 1 ), the user location management means  34  collects the location information on the user&#39;s terminal from terminal location information providing devices (specifically, the location information servers  22   a ,  22   c , and  22   e  and the subscription information servers  22   b  and  22   d ) in the networks  21   a  to  21   e  (step S 2 ) and then the control proceeds to step S 3 . Therefore, when the control proceeds to step S 3 , the location information on the terminal of the user receiving the service becomes referable. 
     In step S 3 , the user location and data center arrangement optimization means  32  determines the appropriate data center in accordance with the location information on the terminal of the user receiving the service (step S 3 ). Here, the appropriate data center is, for example, a data center closest in distance to the terminal of the user receiving the service. The location information on the data center may be previously stored by, for example, the user location and data center arrangement optimization means  32 . Then, the user location and data center arrangement optimization means  32  may determine the distance between the terminal and each data center by using, for example, the location information on the terminal and the location information on each data center and determine the data center closest in distance to the terminal to be a data center appropriate to the terminal. 
     Subsequently, the user location and data center arrangement optimization means  32  determines whether or not it is necessary to transfer the user area and the user data between data centers (step S 4 ). If the data center currently providing the service to the user differs from the data center determined to be appropriate to the user in step S 3 , the user location and data center arrangement optimization means  32  determines that it is necessary to transfer the user area and the like from the data center currently providing the service to the data center determined to be appropriate (Yes in step S 4 ). Meanwhile, if the data center currently providing the service is the same as the data center determined to be appropriate in step S 3 , the user location and data center arrangement optimization means  32  determines that it is unnecessary to transfer the user area and the like (No in step S 4 ). If it is determined that the user area and the user data do not need to be transferred, the processing related to the transfer of the user area and the like is terminated. 
     If it is determined that the user area and the user data need to be transferred, the user location and data center arrangement optimization means  32  instructs the data center currently providing the service to the user to transfer the user area and the user data to the data center determined to be appropriate to the user in step S 3  (step S 5 ). The data center which has received the instruction transfers the user area and the like according to the instruction. 
       FIG. 5  is an explanatory diagram illustrating exchanges of an instruction and the like between the data center management system, data centers, a location information server, and a subscription server in the first method. The data center configuration management means  31  of the data center management system  1  constantly monitors the data centers  11   a  to  11   c  to collect the usage and operating conditions of the data centers (step S 11 ). For example, in addition to the system capacity of each data center, the data center configuration management means  31  collects information on the capacity of the user area used by each user, the user data capacity, the CPU occupancy rates of devices in the data center, the type of service provided to the user by the data center, the user&#39;s usage condition of the service (which service the user is using), and the like. The user location management means  34  may determine the terminal of the user receiving the service from the data center on the basis of the information (step S 1 : See  FIG. 4 ). 
     Moreover, unless the location information on the terminal of the user receiving the service from the data center is collected, the user location management means  34  collects the location information from the location information servers and the subscription information servers in the networks  21   a  to  21   e  as described above (step S 2 : See  FIG. 4 ). In this process, the user location management means  34  specifies a user whose information is to be collected and inquires of the location information server  22   a  and the subscription information server  22   b  for the location information on the terminal of the user (step S 12 ). Although the location information server  22   a  and the subscription information server  22   b  are illustrated in  FIG. 5 , the inquiry may be made to each location information server and each subscription information server. 
     Moreover, in the case of holding the location information on the terminal of the specified user, the location information server  22   a , the subscription information server  22   b , and the like having received the inquiry in step S 12  send the location information as a response to the inquiry in step S 12  to the data center management system  1  (step S 13 ). The user location management means  34  stores the location information on the terminal received in step S 13 . 
     The data center configuration management means  31  collects the information on the network (carrier network) in communication used for the communication by the user&#39;s terminal from the data centers and the user location management means  34  also stores the information. 
     The user location and data center arrangement optimization means  32  then determines the appropriate data center in accordance with the location information on the terminal of the user receiving the service (step S 14 ). The process of step S 14  illustrated in  FIG. 5  corresponds to the process of step S 3  in  FIG. 4 . 
     The user location and data center arrangement optimization means  32  performs the determination process of step S 4  (See  FIG. 4 ) and, if determining that it is necessary to transfer the user area and the like, instructs the data center currently providing the service to the user to transfer the user area and the user data to the data center determined to be appropriate to the user in step S 3  (step S 15 ). Step S 15  corresponds to step S 5  illustrated in  FIG. 4 . In this specification, the description is made taking a case of instructing the data center  11   a  to transfer the user area and the user data to the data center  11   b  as an example. In the data center  11   a  instructed in step S 15 , for example, the server  84   a  requests the server  13   b  to secure the same user area as the user area of the user in the storage  83   a  in the storage  12   b  of the data center  11   b . The server  13   b  of the data center  11   b  secures the user area in the storage  12   b  in response to this request. Furthermore, the server  13   a  of the data center  11   a  sends the user data of the user to the server  13   b  of the data center  11   b  to request the server  13   b  to store the user data into the user area secured anew. The server  13   b  stores the user data sent from the data center  11   a  into the user area secured anew (step S 16 ). The server  13   a  of the data center  11   a  may release the user area of the user in the storage  12   a.    
     After securing the new user area in the storage  12   b  and storing the user data sent from the data center  11   a  into the new user area, the server  13   b  of the data center  11   b  notifies the data center management system  1  of the completion of the transfer of the user area and the like (step S 17 ). 
       FIG. 6  is a flowchart illustrating an example of a processing progress of the data center management system  1  for a transfer of a user area and the like in the second method. The processes the same as those in the first method are designated by the same reference numerals as those in  FIG. 4  and the detailed description of the processes will be omitted. The data center configuration management means  31  of the data center management system  1  constantly monitors the data centers  11   a  to  11   c  to collect the usage and operating conditions of the data centers. This point is the same as in the first method. 
     In the second method, upon detecting the movement of a user&#39;s terminal beyond a certain range, a terminal location information providing device (a location information server or a subscription information server) of each network notifies (sends the location information to) the data center management system  1  of the location information on the terminal after the movement. Then, the user location management means  34  of the data center management system  1  receives and stores the location information on the terminal (step S 21 ). 
     Subsequently, the user location and data center arrangement optimization means  32  determines the appropriate data center in accordance with the location information on the terminal of the user receiving the service (step S 3 ). Further, the user location and data center arrangement optimization means  32  determines whether or not it is necessary to transfer the user area and the user data between data centers (step S 4 ). If determining that it is necessary to transfer the user area and the user data (Yes in step S 4 ), the user location and data center arrangement optimization means  32  instructs the data center currently providing the service to the user to transfer the user area and the user data to the data center determined to be appropriate to the user in step S 3  (step S 5 ). The processes in steps S 3  to S 5  are the same as those in steps S 3  to S 5  (See  FIG. 4 ) in the first method and therefore the description of the processes is omitted here. 
     If it is determined that there is no need to transfer the user area and the user data (No in step S 4 ) or if step S 5  is performed, the user location management means  34  sends a response to the location information received in step S 21  to the location information server or the subscription information server which is a sender of the location information on the terminal of the user (step S 22 ). 
     If it is determined that there is no need to transfer the user area and the user data and the control proceeds to step S 22 , the user location management means  34  may send the notice that the transfer of the user area and the user data was not performed to the location information server or the subscription information server which is the sender of the location information on the terminal of the user. Moreover, if the control proceeds to step S 22  after the execution of step S 5 , the user location management means  34  may send the notice that the transfer of the user area and the user data has been performed to the location information server or the subscription information server which is the sender of the location information on the terminal of the user. 
       FIG. 7  is an explanatory diagram illustrating exchanges of an instruction and the like between the data center management system, the data centers, the location information server, and the subscription server in the second method. 
     The data center configuration management means  31  of the data center management system  1  constantly monitors the data centers  11   a  to  11   c  to collect the usage and operating conditions of the data centers (step S 11 ). For example, in addition to the system capacity of each data center, the data center configuration management means  31  collects information on the capacity of the user area used by each user, the user data capacity, the CPU occupancy rates of devices in the data center, the type of service provided to the user by the data center, the user&#39;s usage condition of the service (which service the user is using), and the like. 
     A terminal location information providing device (a location information server or a subscription information server) of each network monitors the location information on the terminal of the user of the communication carrier. Then, when detecting the movement of the user&#39;s terminal beyond a certain range (step S 31 ), the terminal location information providing device notifies the data center management system  1  of the location information on the terminal obtained after the movement (step S 32 ). 
     For example, if a terminal which has not been detected until then is detected along with the movement of the user (terminal), the location information servers  22   a ,  22   c , and  22   e  in the network of the mobile carrier may notify the data center management system  1  of the location information on the terminal. Moreover, if the moving distance of the detected terminal exceeds a certain range, the location information servers  22   a ,  22   c , and  22   e  may notify the data center management system  1  of the location information on the terminal at that time. Further, for example, if the information on the line installation location of a fixed terminal (the location information on the fixed terminal) contained in the subscription information is updated and the location before the update is a certain distance or more away from the location after the update, the subscription information servers  22   b  and  22   d  of the fixed carrier may notify the data center management system  1  of the location information on the fixed terminal after the update. 
     Immediately after the data center management system  1  receives the location information on the terminal sent in step S 32  (step S 21 : See  FIG. 5 ), the user location management means  34  stores the location information. 
     In addition, the data center configuration management means  31  collects information on the network (carrier network) in communication used for the communication by the user&#39;s terminal from the data centers and the user location management means  34  stores the information, too. 
     Subsequently, the user location and data center arrangement optimization means  32  determines the appropriate data center in accordance with the location information on the terminal of the user receiving the service (step S 14 ). The process of this step S 14  corresponds to the process of step S 3  in  FIG. 6 . Moreover, the process of this step S 14  is the same as the process of step S 14  in the first method. 
     Further, the user location and data center arrangement optimization means  32  performs the determination process of step S 4  (See  FIG. 6 ) and, if determining that it is necessary to transfer the user area and the like, instructs the data center currently providing the service to the user to transfer the user area and the user data to the data center determined to be appropriate to the user in step S 3  (step S  15 ). The process of step S 15  corresponds to the process of step S 5  illustrated in  FIG. 6 . In this specification, the description is made taking a case of instructing the data center  11   a  to transfer the user area and the user data to the data center  11   b  as an example. In the data center  11   a  instructed in step S 15 , for example, the server  84   a  requests the server  13   b  to secure the same user area as the user area of the user, which is secured in the storage  83   a , in the storage  12   b  of the data center  11   b . The server  13   b  of the data center  11   b  secures the user area in the storage  12   b  in response to this request. Furthermore, the server  13   a  of the data center  11   a  sends the user data of the user to the server  13   b  of the data center  11   b  to request the server  13   b  to store the user data into the user area secured anew. The server  13   b  stores the user data sent from the data center  11   a  into the user area secured anew (step S 16 ). The server  13   a  of the data center  11   a  may release the user area of the user in the storage  12   a . After securing the new user area in the storage  12   b  and storing the user data sent from the data center  11   a  into the new user area, the server  13   b  of the data center  11   b  notifies the data center management system  1  of the completion of the transfer of the user area and the like (step S  17 ). The processes of these steps S 15  to S 17  are the same as those of steps S 15  to S 17  in the first method. 
     Upon receiving the notice of step S 17 , the user location management means  34  notifies the location information server or the subscription information server, which is the sender of the location information on the user&#39;s terminal, of the completion of the transfer of the user area and the user data of the user (step S 33 ). The process of this step S 33  corresponds to the process of step S 22  illustrated in  FIG. 6  (if the control proceeds from step S 5  to step S 22 ). 
     Subsequently, the switching operation of the network (access network) appropriate to the service type will be described.  FIG. 8  is a conceptual diagram of a switching operation of a network appropriate to a service type. It is assumed that the user uses a service provided by a cloud service provider via the network  21   b  of the carrier B. In other words, it is assumed that the user&#39;s terminal  17  communicates with the data center  11   a  via the network  21   b  and thereby the user receives the service. Then, for example, it is assumed that the service used by the user is a video distribution service requiring, for example, an extremely-high bit rate or a service required to have a short delay time, if any, while the network  21   b  cannot guarantee such a service quality. If interpreting the situation, the data center management system  1  selects a network able to guarantee the service quality (here, the network is assumed to be the network  21   a ) and causes the switching of the network used for the communication by the user from the network  21   b  to the network  21   a.    
     In contrast, it is assumed that the service used by the user is, for example, a service merely requiring a low bit rate such as a text data distribution or a service not required to have the immediacy of communication, while the network  21   b  of the carrier B has an extremely-high communication quality and requires a high utility rate. If interpreting the situation, the data center management system  1  selects a network that has a minimum required quality of the service and requires a more inexpensive utility rate (here, the network is assumed to be the network  21   a ) and causes the switching of the network used for the communication by the user from the network  21   b  to the network  21   a.    
       FIG. 9  is a flowchart illustrating an example of a processing progress of the data center management system  1  for network switching. The data center configuration management means  31  of the data center management system  1  determines whether or not the information on the type of service used by the user and the type of access network (network) used by the user is collected (step S 41 ). If the information has already been collected (Yes in step S 41 ), the control proceeds to step S 43 . Unless the information has been collected, the data center configuration management means  31  collects the information on the type of service used by the user and the type of network used by the user from the data centers (step S 42 ) and the control proceeds to step S 43 . Here, the information on the type of network is information on the type of communication system such as, for example, 2G, 3G, or LTE. 
     Therefore, when the control proceeds to step S 43 , the information on the type of service used by the user and the type of network used by the user becomes referable. 
     In step S 43 , the service type and network optimization means  33  determines (selects) a network of a type appropriate to the service used by the user (step S 43 ). For example, the service type and network optimization means  33  may previously store which network is appropriate to which service and select the network appropriate to the service used by the user in step S 43 . Alternatively, a network appropriate to the service used by the user may be selected in another method. 
     For example, taking a digital signage service as an example, if the user is using a service of displaying only image data or character information on the terminal, a wide communication bandwidth like in LTE is unnecessary and the requirement for the immediacy is not high. Therefore, as the type of access network appropriate to such a service, 2G (alternatively, 3G, a personal handy-phone system [PHS], or the like) is previously determined and then a network of the determined type is selected. 
     Moreover, if it is detected that the user is using a service of distributing a video file from video data on the data center, LTE or the like with a wide communication bandwidth and a short communication delay is determined in advance as the type of access network appropriate to the service and then the determined type of network is selected. For example, after the service used by the user is switched to a video file distribution service, switching is performed so as to select the LTE network as described above. 
     After step S 43 , the service type and network optimization means  33  determines whether it is necessary to change the network with reference to the type of network currently used by the user collected in step S 41  and the type of network determined in step S 43  (step S 44 ). If the type of network currently used by the user collected in step S 41  differs from the type of network determined in step S 43 , the service type and network optimization means  33  determines that the network currently used by the user needs to be switched to the network of the type determined in step S 43  (Yes in step S 44 ). On the other hand, if the type of network currently used by the user is the same as the type of network determined in step S 43 , the service type and network optimization means  33  determines that the network does not need to be switched (No in step S 44 ). If determining that the network does not need to be switched, the service type and network optimization means  33  terminates the processing of network switching. 
     If determining that the network needs to be switched, the service type and network optimization means  33  instructs a communication carrier (specifically, an NW controller) to switch the network (step S 45 ). 
       FIG. 10  is an explanatory diagram illustrating exchanges of an instruction and the like between the data center management system, data centers, and NW controllers in the network switching process. The data centers  11   a ,  11   b , and the like constantly monitor the type of service currently used by the user and the type of access network (network) used by the user and retain the information on the type of service currently used by the user and on the network used by the user (step S 51 ). 
     Moreover, as has been described, the data center configuration management means  31  of the data center management system  1  constantly monitors the data centers  11   a  to  11   c  to collect the usage and operating conditions of the data centers (step S 11 ). Specifically, the data center configuration management means  31  inquires of each data center for information on the type of service currently used by the user, the type of network used by the user, and the like (step S 52 ). The data center which has received the inquiry sends the information on the type of service currently used by the user, the type of network used by the user, and the like, as a response to step S 52 , to the data center management system  1  (step S 53 ) and the data center configuration management means  31  of the data center management system  1  receives the information. 
     Thereafter, the service type and network optimization means  33  determines the network appropriate to the service on the basis of the type of service currently used by the user (step S 54 ). The process of step S 54  corresponds to the process of step S 43  in  FIG. 9 . 
     The service type and network optimization means  33  then performs the determination process of step S 44  (See  FIG. 9 ). If determining that it is necessary to change the network, the service type and network optimization means  33  instructs the NW controller of the network currently used by the user to switch the network (step S 55 ). In the example illustrated in  FIG. 10 , there is illustrated a case where the network currently used by the user is the network  21   a  (See  FIG. 1 ) and the NW controller  23   a  in the network  21   a  is instructed to switch the network. 
     When giving the instruction to switch the network (step S 55 ), the service type and network optimization means  33  sends information for specifying a target user for network switching and information for specifying the type of network as a switching destination to the NW controller  23   a  of the network currently used by the user. The NW controller  23   a , which has received the instruction, performs a process of switching the network used by the specified user from the network corresponding to the NW controller  23   a  to the network corresponding to the NW controller  23   b  in cooperation with the NW controller (the NW controller  23   b  in the example illustrated in  FIG. 10 ) in the network corresponding to the specified type of network as the switching destination (step S 56 ). In step S 56 , the NW controllers  23   a  and  23   b  switch the network without changing the IP address allocated to the user&#39;s terminal  17 . This switching process may be performed by the method described in “3GPP TS23.401” or “3GPP TS23.402” as described above. 
       FIG. 11  is an explanatory diagram illustrating an optimization target range  71  for the access network switching in a protocol stack. In the case of switching the network without changing the IP address allocated to the user&#39;s terminal  17 , L 1  and L 2  in the network and the terminal are optimized for the network switching as illustrated in  FIG. 11 . 
     The NW controller  23   a , which has received the instruction in step S 55 , switches the network of the user to the network appropriate to the service (step S 56 ) and thereafter notifies the data center management system  1  of the completion of the network switching (step S 57 ). 
     According to the operations described hereinabove, it is possible to provide the same level of services by using an appropriate access network, independently of a user&#39;s location with the minimum delay in user access. 
     According to the exemplary embodiment, the user data and the use area (user area) are able to be dynamically managed according to a user&#39;s location, and therefore the user is able to receive services with the same level of delay time independently of the user&#39;s location. In addition, for example, if the service used by the user is a service satisfied with a narrow communication bandwidth, it is possible to select a lower-cost access network. Moreover, for example, if the service used by the user is a service requiring a higher QoS, it is possible to select an access network capable of guaranteeing a wide bandwidth and low latency even though the cost is high. In other words, according to the exemplary embodiment, geographic fairness is secured when the user uses the service in the cloud and an access network appropriate to the service type is able to be dynamically managed by a could service provider, instead of by the user, thereby improving the user&#39;s convenience. 
     The following describes a modification of this exemplary embodiment. In the above exemplary embodiment, there has been described a case where the data center management system  1  collects information from the location information servers  22   a ,  22   c , and  22   e  and the subscription information servers  22   b  and  22   d  of the carriers. The data center management system  1  may collect location information on the user&#39;s terminal by using a global positioning (GPS) device, which is mounted on a smartphone, a personal computer, or the like used as the user&#39;s terminal. In other words, the user&#39;s terminal may derive the location information on the terminal itself by using the GPS device provided in the terminal and send the location information to the data center management system  1 . 
     Further, in the above exemplary embodiment, there has been described a case where the network is switched by a carrier-driven method (specifically, the NW controller switches the network). In the case where the terminal is loaded with application software (hereinafter, simply referred to as the application) capable of switching among a plurality of sessions, the network switching may be made by the control of the data centers and the terminal. Specifically, the data center management system  1  may instruct the data centers and the terminal to perform network switching. 
       FIG. 12  is an explanatory diagram illustrating an optimization target range  81  for performing access network switching in this case. In the case of performing network switching by using data centers and the terminal, as illustrated in  FIG. 12 , all of the L 3  and lower layers in the protocol stack are targets of switching and therefore the control by the access network (network) is unnecessary. 
     The following describes an example of a minimum configuration of the present invention.  FIG. 13  is a block diagram illustrating a minimum configuration example of the communication service providing system of the present invention.  FIG. 14  is a block diagram illustrating a minimum configuration example of the data center management system of the present invention. 
     The communication service providing system according to the present invention includes a plurality of data centers  51 , which provide services to the user by communicating with the user&#39;s terminal, and a data center management system  1  which manages the data centers  51 . When providing the service to the user, each of the data centers  51  secures a user area, which is a storage area for the user for use in providing the service, and stores user data, which is data for the user for use in providing the service, into the user area. 
     The data center management system  1  includes location information collection means  71  (for example, the user location management means  34 ), user data and the like transfer instruction means  72  (for example, the user location and data center arrangement optimization means  32 ), service type and the like collection means  73  (for example, the data center configuration management means  31 ), and network switching control means  74  (for example, the service type and network optimization means  33 ). 
     The location information collection means  71  collects the location information on the terminal of the user receiving a service from any one of the data centers. 
     The user data and the like transfer instruction means  72  determines a data center closest to a location indicated by the location information. If the data center concerned differs from the data center currently providing a service to the user, the user data and the like transfer instruction means  72  instructs the data center currently providing the service to the user to transfer the user data and the user area of the user to the data center closest to the location indicated by the location information. 
     The service type and the like collection means  73  collects information on the type of service provided to the user and the type of network used for providing the service to the user from the respective data centers. 
     The network switching control means  74  determines the type of network appropriate to the type of service provided to the user by the data center. If the type of the network does not match the information on the type of network collected by the service type and the like collection means, the network switching control means  74  performs control to switch the network used for providing the service to the user to the network appropriate to the type of the service. 
     The advantageous effects of the present invention are achieved by the configuration described hereinabove. 
     Moreover, for example, if the type of network appropriate to the type of service provided to the user by the data center does not match the information on the type of network collected by the service type and the like collection means, the network switching control means  74  instructs the network switching means in the network used for providing the service to the user to switch the network used for the communication between the terminal and the data center to the network appropriate to the type of the service. 
     The location information collection means  71  may collect the location information on the user&#39;s terminal from the terminal location information providing devices managed by the respective communication carriers. 
     The location information collection means  71  may collect the location information on the terminal from the user&#39;s terminal. 
     Some or all of the above exemplary embodiments can be described as follows, but are not limited to the following. 
     (Supplementary Note 1) A communication service providing system including: a plurality of data centers which provide services to a user by communicating with a terminal of the user; and a data center management system which manages the respective data centers, wherein: each data center, when providing the service to the user, secures a user area which is a storage area for the user for use in providing the service and stores user data which is data for the user for use in providing the service into the user area; and the data center management system includes: a location information collection unit which collects location information on the terminal of the user receiving the service from any one of the data centers; a user data and the like transfer instruction unit which determines a data center closest to a location indicated by the location information and, in the case where the data center differs from the data center currently providing the service to the user, instructs the data center currently providing the service to the user to transfer the user data and the user area of the user to the data center closest to the location indicated by the location information; a service type and the like collection unit which collects information on the type of service provided to the user and the type of network used for providing the service to the user from the respective data centers; and a network switching control unit which determines the type of network appropriate to the type of service provided to the user by the data center and, in the case where the type of network does not match the information on the type of network collected by the service type and the like collection unit, performs control to switch the network used for providing the service to the user to the network appropriate to the type of service. 
     (Supplementary Note 2) The communication service providing system according to Note 1, wherein, in the case where the type of network appropriate to the type of service provided to the user by the data center does not match the information on the type of network collected by the service type and the like collection unit, the network switching control unit instructs a network switching unit in the network used for providing the service to the user to switch the network for the communication between the terminal and the data center to the network appropriate to the type of service. 
     (Supplementary Note 3) The communication service providing system according to Note 1 or 2, wherein the location information collection unit collects the location information on the user&#39;s terminal from terminal location information providing devices managed by respective communication carriers. 
     (Supplementary Note 4) The communication service providing system according to Note 1 or 2, wherein the location information collection unit collects the location information on the terminal from the user&#39;s terminal 
     (Supplementary Note 5) A data center management system which manages a plurality of data centers which provide services to a user by communicating with a terminal of the user, secures a user area which is a storage area for the user for use in providing the services when providing the services to the user, and stores user data which is data for the user for use in providing the services into the user area, the system including: a location information collection unit which collects location information on the terminal of the user receiving the service from any one of the data centers; a user data and the like transfer instruction unit which determines a data center closest to a location indicated by the location information and, in the case where the data center differs from the data center currently providing the service to the user, instructs the data center currently providing the service to the user to transfer the user data and the user area of the user to the data center closest to the location indicated by the location information; a service type and the like collection unit which collects information on the type of service provided to the user and the type of network used for providing the service to the user from the respective data centers; and a network switching control unit which determines the type of network appropriate to the type of service provided to the user by the data center and, in the case where the type of network does not match the information on the type of network collected by the service type and the like collection unit, performs control to switch the network used for providing the service to the user to the network appropriate to the type of service. 
     This application claims priority to Japanese Patent Application No. 2010-273746 filed on Dec. 8, 2010, and the entire disclosure thereof is hereby incorporated herein by reference. 
     Although the present invention has been described with reference to the exemplary embodiments hereinabove, the present invention is not limited thereto. A variety of changes, which can be understood by those skilled in the art, may be made in the configuration and details of the present invention within the scope thereof. 
     INDUSTRIAL APPLICABILITY 
     The present invention is preferably applied to a communication service providing system which provides services from data centers via a network. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  Data center management system 
               11   a ,  11   b ,  11   c  Data center 
               17  Terminal 
               22   a ,  22   c ,  22   e  Location information server 
               22   b ,  22   d  Subscription information server 
               23   a ,  23   b  NW controller 
               31  Data center configuration management means 
               32  User location and data center arrangement optimization means 
               33  Service type and network optimization means 
               34  User location management means 
               35  Data center communication means 
               36  Carrier system communication means