JP5793796B2 - Communication system and communication method - Google Patents

Description

  The present invention relates to a communication system, and more particularly to a communication system that communicates via an access gateway.

  Conventionally, a load distribution technique in an access gateway of a mobile radio communication system has been proposed (see, for example, Patent Document 1).

  The technology described in Patent Document 1 is a technology related to an access gateway (AGW) including a C-AGW (Control Access Gateway) for processing control messages and a plurality of U-AGWs (User Access Gateway) for processing data packets. is there. In the mobile radio communication system described in Patent Document 1, when a tunnel setup request for mobile station handover occurs in order to distribute the U-AGW load and reduce the overhead, The new U-AGW in the minimum load state is searched from a plurality of U-AGWs, and the load state of the new U-AGW when the tunnel termination point for the mobile station is changed to the new U-AGW is estimated To do. Then, when the estimated load state satisfies a predetermined condition, the C-AGW designates the new U-AGW as a tunnel termination point for the mobile station, and the estimated load state does not satisfy the predetermined condition In this case, a tunnel for data packet transfer is formed between the base station and the U-AGW by designating the address of the current U-AGW as a tunnel termination point.

JP 2010-187267 A

  In the prior art, when a tunnel setting request is generated, a tunnel is allocated to a U-AGW in a minimum load state among a plurality of U-AGWs. However, when the logic for selecting a new U-AGW by such a method is used, only the load state of the entire U-AGW at the time of connection is considered, and the session load specific to each user is not considered. For this reason, in the prior art, there is a problem that the load after activation by the user is not considered.

  For example, when a heavy load and active mode session by a heavy user is concentrated on a specific U-AGW, processing in the specific U-AGW becomes heavy. The session assigned to the U-AGW whose processing is heavy decreases in throughput.

  On the other hand, in the U-AGW in which light user sessions with a low load are concentrated, an event such as excess processing capacity occurs.

  As described above, when there is a session load specific to each user and the load distribution method focusing only on the load on the U-AGW side is applied, in the mobile radio communication system, how the load is applied depending on the allocated session. This causes a problem that the resources of the AGW are not used efficiently.

  Further, for example, the conventional session allocation to the U-AGW is performed only at the time of new connection and at the time of handover. For this reason, a session by a terminal that is less likely to move and is always connected is always assigned to a specific U-AGW unless it is reconnected once it is connected. And when the session of a heavy user concentrates on the U-AGW which has been allocated, there is a problem that the state where the throughput is low continues.

  The present invention solves the above-mentioned problems and prevents the load from being concentrated on a specific U-AGW.

According to a representative example of the present invention, a base station that communicates wirelessly with a terminal , a plurality of gateways that communicate with the terminal via the base station, and an agent device that communicates with the terminal via each gateway The plurality of gateways include a processor, a memory, and a network interface, are connected to the gateways via the network interface, and are connected between the terminal and the agent device. The first gateway communicates with the terminal by accommodating the established session, and the first gateway has a plurality of communication information indicating a communication status in the session accommodated by each of the gateways, and a plurality of assignments assigned to the session according to the communication information And a threshold management table including a value indicating the type. And a gateway management table indicating the number of sessions accommodated by each gateway for each type assigned to the session, and a path establishment request including designation of a session held by the terminal that starts communication Is received, the communication information in the session specified by the path establishment request is acquired, and the type is set in the session specified by the path establishment request according to the acquired communication information and the threshold management table. According to the allocation, the allocated type, and the gateway management table, a gateway that accommodates the session specified by the path establishment request is selected.

  According to an embodiment of the present invention, it is possible to prevent a load from being concentrated on a specific U-AGW.

It is a block diagram which shows the mobile radio system of the Example of this invention. It is a block diagram which shows the physical structure of BS of the Example of this invention. It is explanatory drawing which shows the transfer destination address management table for BS of the Example of this invention. It is a block diagram which shows the physical structure of HA of the Example of this invention. It is explanatory drawing which shows the forwarding address management table for HA of the Example of this invention. It is a block diagram which shows the physical structure of AAA of the Example of this invention. It is a block diagram which shows the physical structure of C-AGW of the Example of this invention. It is explanatory drawing which shows the U-AGW management table of the Example of this invention. It is explanatory drawing which shows the session management table for C-AGW of the Example of this invention. It is explanatory drawing which shows the threshold value management table of the Example of this invention. It is a block diagram which shows the physical structure of U-AGW of the Example of this invention. It is explanatory drawing which shows the session management table for U-AGW of the Example of this invention. It is a sequence diagram which shows the process at the time of the initial connection of MS of the Example of this invention. It is a flowchart which shows the U-AGW selection process of the Example of this invention. It is a sequence diagram which shows the process performed when the session of the active state of the Example of this invention changes to an idle state. It is a sequence diagram which shows the process performed when the session of an idle state of the Example of this invention changes to an active state. It is a flowchart which shows the threshold value calculation process of the Example of this invention.

  Examples described below will be described with reference to the drawings.

  The C-AGW in the present embodiment selects the U-AGW according to the communication status for each user in the session when selecting the U-AGW to communicate with the terminal, and sets the U-AGW load in the AGW for each user whose communication status is close By distributing the load to a specific U-AGW is prevented.

  Further, when the session state transitions from the idle state to the active state, the C-AGW selects the U-AGW according to the communication status, and sets the path between the selected U-AGW and the terminal again. Thereby, the load distribution opportunity of U-AGW can be increased and the time when a load concentrates on any U-AGW can be shortened.

  FIG. 1 is a block diagram showing a mobile radio system according to an embodiment of the present invention.

  A mobile radio system according to an embodiment of the present invention includes a core network 1, a home agent (HA) 2, an authentication server (AAA) 3, an access gateway (AGW) 4, an access network 7, a plurality of radio base stations (BS) 10, A plurality of mobile bodies (MS) 20 are provided.

  MS20 (MS20A, MS20B) is a terminal used by a user, such as a mobile phone or a mobile PC.

  BS10 (BS10A to BS10N) generates a radio communication area (cell) according to radio transmission power and communicates with MS 20 located in the radio communication area by radio.

  The AAA 3 is connected to the core network 1 and authenticates the MS 20 via the AGW 4 when the MS 20 establishes communication with the HA 2.

  The HA 2 is connected to, for example, the Internet or the public communication network 8 and transmits uplink user data from the MS 20 to the Internet or the public communication network 8. Further, the HA 2 transmits downlink user data addressed to the MS 20 from the Internet or the public communication network 8 to the MS 20 via the AGW 4 and the BS 10.

  AAA 3 and HA 2 are connected to AGW 4 via core network 1.

  The AGW 4 includes a C-AGW 5 that processes control data and a plurality of U-AGWs 6 (U-AGW 6-1 to U-AGW 6-m) that process user data. C-AGW 5 and U-AGW 6 are connected by a bus 9.

  The C-AGW 5 and each U-AGW 6 included in the AGW 4 are connected to the BS 10 via the access network 7.

  FIG. 2 is a block diagram illustrating a physical configuration of the BS 10 according to the embodiment of this invention.

  The BS 10 includes a radio reception antenna 108, a radio communication interface 101, a memory 102, a processor 104, and a communication interface 106, which are connected by a bus 107.

  The radio reception antenna 108 is an antenna for communicating with the MS 20 by radio, and the radio communication interface 101 is a network interface connected to the radio reception antenna 108. The communication interface 106 is a network interface for the BS 10 to connect to the access network 7.

  The processor 104 is an arithmetic device such as a CPU. The processor 104 executes a process or the like developed in the memory 102 by reading data stored in the memory 102.

  The memory 102 is a storage device and includes a communication processing process 103 and a BS transfer destination address management table 1000. The communication processing process 103 is a process for the BS 10 to communicate with the MS 20 or the access network 7.

  The BS forwarding address management table 1000 includes information indicating to which IP address the uplink user data transmitted by each MS 20 is to be forwarded.

  FIG. 3 is an explanatory diagram illustrating the BS forwarding address management table 1000 according to the embodiment of this invention.

  The BS forwarding address management table 1000 includes an MSID 1001 and a forwarding IP address 1002.

  The MSID 1001 includes an identifier that uniquely identifies the MS 20. In the transfer destination IP address 1002, an IP address that is a transfer destination of the uplink user data transmitted from the MS 20 is registered.

  FIG. 4 is a block diagram illustrating a physical configuration of the HA 2 according to the embodiment of this invention.

  The HA 2 includes a communication interface 1 (21), a communication interface 2 (25), a memory 22, and a processor 24, which are connected by a bus 26.

  The communication interface 1 (21) is a network interface for connecting to the core network 1, and the communication interface 2 (25) is a network interface for connecting the HA 2 to the Internet or the public communication network 8.

  The processor 24 is an arithmetic device such as a CPU. The processor 24 executes a process or the like developed in the memory 22 by reading data stored in the memory 22.

  The memory 22 is a storage device, and includes a communication processing process 23 and an HA transfer destination address management table 200. The communication processing process 23 is a process for the HA 2 to communicate with the core network 1 and the Internet or the public communication network 8.

  The transfer destination address management table 200 for HA includes an address given to the downlink user data by the HA 2 because the HA 2 transmits the downlink user data to each MS 20. Further, the HA 2 can specify the destination of the U-AGW 6 that transmits the downlink user data to be transmitted to the MS 20 by referring to the HA transfer destination address management table 200.

  FIG. 5 is an explanatory diagram illustrating the HA transfer destination address management table 200 according to the embodiment of this invention.

  The HA transfer destination address management table 200 includes an MSID 201, a transfer destination IP address 202, and an assigned IP address 203. The MSID 201 includes an identifier for uniquely identifying the MS 20.

  In the transfer destination IP address 202, an IP address indicating a transfer destination to be assigned to downlink user data transmitted to the MS 20 is registered. The transfer destination IP address 202 in the present embodiment indicates an IP address for the HA 2 that the U-AGW 6 has.

  The assigned IP address 203 indicates an IP address assigned to the MS 20.

  FIG. 6 is a block diagram illustrating a physical configuration of AAA 3 according to the embodiment of this invention.

  The AAA 3 has a communication interface 31, a memory 32, a processor 34, and a user data DB 35, which are connected by a bus 36. The communication interface 31 is a network interface for the AAA 3 to connect to the core network 1.

  The processor 34 is an arithmetic device such as a CPU. The processor 34 executes a process or the like developed in the memory 32 by reading data stored in the memory 32.

  The memory 32 is a storage device and includes a communication processing process 33. The communication processing process 33 executes processing for the AAA 3 to communicate with the core network 1.

  The user data DB 35 is a storage device that holds user information and information related to the MS 20. The user data DB 35 includes information for specifying a user. Specifically, the user data DB 35 includes MSID (identifier of the MS 20), authentication information such as a user ID, and communication information indicating a user's communication status within a certain period.

  The user data DB 35 includes information determined by a contract or the like when the user starts using the MS 20. The user communication information includes, for example, the packet transfer amount. In the following, an embodiment in which the communication information includes a packet transfer amount will be described.

  Furthermore, the communication information included in the user data DB 35 may be communication information acquired by the U-AGW 6 when the user communicated in the past using the MS 20, and is used when the user has never used the MS 20. The predetermined communication information may be used.

  FIG. 7 is a block diagram illustrating a physical configuration of the C-AGW 5 according to the embodiment of this invention.

  The C-AGW 5 includes an external communication interface 1 (51), an external communication interface 2 (52), an internal interface 53, a memory 54, a processor 55, and an HDD 56, which are connected by a bus 57.

  The external communication interface 1 (51) is a network interface for the C-AGW 5 to connect to the access network 7. The external communication interface 2 (52) is a network interface for the C-AGW 5 to connect to the core network 1. The internal interface 53 is a network interface for the C-AGW 5 to connect to the bus 9 of the AGW 4.

  The memory 54 includes a communication processing process 58, a U-AGW management table 500, a C-AGW session management table 510, and a threshold management table 520. The communication processing process 58 is a process for the C-AGW 5 to communicate with the access network 7 or the core network 1 or the like.

  Also, the communication processing process 58 of this embodiment is a process for performing a U-AGW selection process 800 and a threshold value calculation process 900 in the threshold value management table 520 described later. In this embodiment, the communication processing process 58 is shown as a single process, but may include a plurality of processes. That is, a different process for executing the threshold calculation process 900 and the U-AGW selection process 800 described later may be included.

  The C-AGW 5 may include a processing unit such as an integrated circuit instead of holding the communication processing process 58.

  The U-AGW management table 500 is a table indicating the number of sessions accommodated by each U-AGW 6 in the AGW 4. The C-AGW session management table 510 is a table indicating which U-AGW 6 accommodates a session held by each MS 20. The threshold management table 520 is a table showing thresholds for assigning types to each session.

  FIG. 8 is an explanatory diagram illustrating the U-AGW management table 500 according to the embodiment of this invention.

  The U-AGW management table 500 includes a U-AGW number 501, an IP address 502, an IP address 503, and the number of active sessions 504. The U-AGW number 501 includes an identifier for identifying the U-AGW 6 that the AGW 4 has.

  The IP address 502 includes an IP address for the BS 10 assigned to the U-AGW 6. The value stored in IP address 502 corresponds to the value stored in transfer destination IP address 1002 of BS transfer destination address management table 1000.

  The IP address 503 includes an IP address for HA2 assigned to the U-AGW6. The value stored in the IP address 503 corresponds to the value stored in the transfer destination IP address 202 of the HA transfer destination address management table 200.

  The number of active sessions 504 is a session accommodated in the U-AGW 6 and includes the number of sessions in an active state. The active state indicates a state of a session in which packets are frequently transmitted and received in the session between the MS 20 and the HA 2.

  The number of active sessions 504 includes a column 504 [1] to a column 504 [K] indicating the number of sessions for each type of session accommodated by each U-AGW 6. The type in this embodiment will be described later.

  FIG. 9 is an explanatory diagram illustrating the C-AGW session management table 510 according to the embodiment of this invention.

  The C-AGW session management table 510 includes an MSID 511, a packet transfer amount 512, a accommodated U-AGW 513, a state 514, and a type 515.

  The MSID 511 indicates an identifier for uniquely identifying the MS 20. Further, the C-AGW 5 can uniquely identify the combination of the MS 20 and the session by the MSID 511 in the C-AGW session management table 510.

  In this embodiment, one MS 20 holds one session. Even if a plurality of users use the casing of one mobile terminal, one MSID is assigned to each user according to the user ID and the like, so one MS 20 corresponds to one user and Corresponds to one session.

  The packet transfer amount 512 is a value indicating the communication status in each session. For example, the packet transfer amount 512 indicates a total value of the packet amount of uplink user data in each session and the packet amount of downlink user data in each session.

  The packet transfer amount stored in the packet transfer amount 512 may be a packet transfer amount transmitted / received from each MS 20 per unit time, or may be a packet transfer amount in a predetermined time zone during a day. The packet transfer amount stored in the packet transfer amount 512 may be an average value of the packet transfer amount per unit time in a predetermined period. That is, the packet transfer amount 512 may include any value as long as it can quantitatively indicate the communication status in each session.

  The accommodation U-AGW 513 indicates the U-AGW 6 that accommodates each session. The value stored in the accommodated U-AGW 513 corresponds to the value stored in the U-AGW number 501 of the U-AGW management table 500.

  A state 514 indicates the state of the session. The state 514 in the present embodiment indicates “Active” when the session is active, and indicates “idle” when the session is idle. The idle state in this embodiment will be described later.

  Type 515 indicates the type of each session. The type will be described later.

  FIG. 10 is an explanatory diagram illustrating the threshold management table 520 according to the embodiment of this invention.

  The threshold management table 520 includes a type 521, a session ratio 522, a threshold 523, and an initial threshold 524. The threshold management table 520 has an entry for each session type. Since there are K types (K is 1 or more) in this embodiment, the threshold management table 520 of this embodiment has K entries.

  Type 521 indicates the type of session.

  The session type in this embodiment is a type assigned to a session in descending order of the load applied to the U-AGW 6 depending on the communication status in the session. For example, different types are assigned to a session with a large amount of packets to be communicated and a session with a small amount of packets to be communicated, such as a session by a heavy user.

  In the type 521 in this embodiment, an identifier with a smaller number is stored as the load applied to the U-AGW 6 is heavier.

  The session ratio 522 indicates the ratio of the number of sessions assigned to each type indicated by the type 521 to the total number of sessions accommodated in the AGW 4.

  The threshold value 523 indicates a criterion of communication status in each session, which is used to assign each type indicated by the type 521 to each session.

  For example, when the communication status is determined according to the packet transfer amount, the threshold value 523 stores a threshold value of the packet transfer amount. Therefore, the threshold value 523 illustrated in FIG. 10 includes a threshold value for comparison with the packet transfer amount 512 of the C-AGW session management table 510.

  The value of the threshold value 523 is updated by an update process of the threshold value management table 523 described later. The initial threshold value 524 indicates an initial value stored in the threshold value 523.

  Values of type 521, session ratio 522, and initial threshold value 524 are stored in advance by an administrator or the like.

  Each entry in the threshold management table 520 is stored in the threshold management table 520 so that the value of the type 521 is in ascending order and the value of the threshold 523 is in descending order for the type assignment process to the session described later.

  The value stored in the type 515 of the C-AGW session management table 510 corresponds to the value stored in the type 521 of the threshold management table 520.

  FIG. 11 is a block diagram illustrating a physical configuration of the U-AGW 6 according to the embodiment of this invention.

  The U-AGW 6 includes an external communication interface 1 (61), an external communication interface 2 (62), an internal communication interface 63, a memory 64, and a processor 65, which are connected by a bus 67.

  The external communication interface 1 (61) is a network interface for the U-AGW 6 to connect to the access network 7. The external communication interface 2 (62) is a network interface for the U-AGW 6 to connect to the core network 1. The internal communication interface 63 is a network interface for the U-AGW 6 to connect to the bus 9 of the AGW 4.

  The processor 65 executes a process or the like developed in the memory 64 by reading data stored in the memory 64.

  The memory 64 includes a communication processing process 68 and a U-AGW session management table 600. The communication processing process 68 is a process for the U-AGW 6 to communicate with the access network 7, the core network 1, and the AGW 4. The U-AGW session management table 600 shows sessions accommodated by the U-AGW 6.

  The communication processing process 68 is a process for acquiring communication information indicating the communication status in the session accommodated by the U-AGW 6. Moreover, it is a process for transmitting the acquired communication information, for example, the packet transfer amount to the C-AGW 5.

  The communication processing process 68 in the present embodiment is a single process, but may include a plurality of processes for each of the processes described above. Further, the U-AGW 6 may include a processing unit such as an integrated circuit instead of holding the communication processing process 68.

  FIG. 12 is an explanatory diagram illustrating the U-AGW session management table 600 according to the embodiment of this invention.

  The U-AGW session management table 600 includes an MSID 601, a state 602, a packet transfer amount 603, a transfer destination HA 604, and a transfer destination BS 605.

  The MSID 601 is an identifier that uniquely indicates the MS 20. Further, the MSID 601 is an identifier that uniquely indicates a combination of the MS 20 and the session, like the MSID 511 of the C-AGW session management table 510.

  The state 602 indicates the state of each session, similar to the state 514 of the C-AGW session management table 510. The packet transfer amount 603 indicates the total value of the uplink user data packet amount in each session and the downlink user data packet amount in each session.

  The packet transfer amount stored in the packet transfer amount 603 may be the packet transfer amount transmitted / received from each MS 20 per unit time, like the packet transfer amount 512 in the C-AGW session management table 600, or within the day. The packet transfer amount in a predetermined time zone may be used. In other words, the packet transfer amount 603 may include any value as long as it is a value that can quantitatively indicate the communication status in the session by each MS 20.

  The transfer destination HA 604 indicates the destination of HA 2 that is the transfer destination of the uplink user data transmitted from the MS 20. The transfer destination BS 605 indicates a destination of the BS 10 that is a transfer destination of downlink user data transmitted to the MS 20.

  The value stored in the MSID 1001 of the BS transfer destination address management table 1000, the value stored in the MSID 201 of the HA transfer destination address management table 200, the value stored in the MSID 511 of the C-AGW session management table 510, The values stored in the MSID 601 of the U-AGW session management table 600 correspond to each other. The value stored in the packet transfer amount 512 of the C-AGW session management table 510 corresponds to the value stored in the packet transfer amount 603 of the U-AGW session management table 600.

  FIG. 13 is a sequence diagram illustrating processing at the time of initial connection of the MS 20A according to the embodiment of this invention.

  The process shown in FIG. 13 is a process in which the MS 20A establishes a session with the HA 2 because the MS 20A starts communication with the Internet or the public communication network 8.

  When the MS 20A connects to the network, that is, when the MS 20A starts communication with the Internet or the public communication network 8, the MS 20A transmits a connection request to the C-AGW 5 via the BS 10A (SQ001 and SQ002). .

  After receiving the connection request, the C-AGW 5 specifies an authentication method for authenticating the MS 20A. Then, a connection request response including a value indicating the designated authentication method is returned to the MS 20A via the BS 10A (SQ003 and SQ004).

  After receiving the connection request response, the MS 20A generates an authentication request by the authentication method designated by the C-AGW 5. Then, the generated authentication request is transmitted to AAA3 via BS 10A and C-AGW 5 (SQ005, SQ006, and SQ007).

  After receiving the authentication request, MS 20A and AAA 3 perform authentication processing of MS 20A via BS 10A and C-AGW 5 (SQ008, SQ009, and SQ010).

  After the authentication process of the MS 20A is completed, the AAA 3 transmits an authentication response to the MS 20A via the C-AGW 5 and the BS 10A (SQ011, SQ013, and SQ014).

  Here, after SQ008, AAA3 generates an authentication response including an MSID that uniquely identifies MS 20A. In SQ011, SQ013, and SQ014, the generated authentication response is sent to C-AGW5, BS10A, and MS20A. Send.

  After receiving the authentication response, the C-AGW 5 registers the MSID included in the received authentication response in the MSID 511 of a new entry in the C-AGW session management table 510 (SQ012). After SQ012, the C-AGW 5 generates a user information acquisition request including the MSID registered in the C-AGW session management table 510. Then, the C-AGW 5 transmits the generated user information acquisition request to the AAA 3 (SQ015).

  After receiving the user information acquisition request, the AAA 3 searches the user data DB 35 of the AAA 3 using the MSID included in the received user information acquisition request. Then, AAA3 acquires the user information of MS 20A from user data DB 35 according to the search result (SQ016).

  The user information acquired in SQ016 includes the packet transfer amount transmitted / received within a certain period by the MS 20A, that is, communication information indicating the communication status in the session held by the MS 20A. If AAA3 does not hold the past packet transfer amount of the session held by MS 20A, AAA3 may include the packet transfer amount specified in advance by the administrator or the like in the user information.

  The AAA 3 transmits the user information acquired in SQ016 to the C-AGW 5 as a user information notification (SQ017).

  After receiving the user information notification, the C-AGW 5 sets the packet transfer amount included in the received user information in the entry of the C-AGW session management table 510 in which the MSID is stored in SQ012 (that is, the entry of the MS 20A). The packet transfer amount 512 is registered (SQ018).

  On the other hand, after receiving the authentication response, the MS 20A transmits a path establishment request to the C-AGW 5 via the BS 10A (SQ019 and SQ020). Here, the path establishment request transmitted to the C-AGW 5 includes the MSID indicating the session held by the MS 20A and the IP address indicating the BS 10A.

  After receiving the path establishment request, the C-AGW 5 performs a U-AGW selection process 800 described later, and selects the U-AGW 6 to which the MS 20A is connected (SQ021). In the following description, for example, it is assumed that C-AGW 5 is selected by U-AGW 6-1 in SQ021.

  After SQ021, the C-AGW 5 refers to the path establishment request received in SQ020 and the C-AGW session management table 510, and generates a path establishment request. Then, the generated path establishment request is transmitted to the U-AGW 6-1 selected in SQ021 (SQ022).

  The path establishment request transmitted to the U-AGW 6-1 in SQ022 includes the IP address of the BS 10A, the MSID of the MS 20A, and the packet transfer amount of the MS 20A. The C-AGW 5 acquires the IP address of the BS 10A to be included in the path establishment request from the path establishment request received from the BS 10A. Further, the MSID and packet transfer amount included in the path establishment request are acquired from the MSID 511 and the packet transfer amount 512 of the C-AGW session management table 510.

  After receiving the path establishment request, the U-AGW 6-1 stores the session information of the session held by the MS 20A in the U-AGW session management table 600 based on the path establishment request received in SQ022 (SQ023).

  Specifically, in SQ023, the U-AGW 6-1 registers the MSID of the MS 20A included in the path establishment request received in SQ022, in the MSID 601 of the new entry in the U-AGW session management table 600. Also, the U-AGW 6-1 registers the packet transfer amount of the MS 20A included in the path establishment request received in SQ022 in the packet transfer amount 603 of the new entry.

  In SQ023, the U-AGW 6-1 registers the IP address of the BS 10A included in the path establishment request received in SQ022 in the transfer destination BS605 of the new entry. Then, the U-AGW 6-1 registers a value indicating “Active” in the state 602 of the new entry.

  After SQ023, U-AGW6-1 transmits a path establishment response to MS20A via C-AGW5 and BS 10A (SQ024, SQ025, and SQ027). The path establishment response transmitted from the C-AGW 5 to the BS 10A includes an MSID (MSID included in the path establishment request) indicating the session that established the path, and an IP address (IP for the BS 10A of the U-AGW6-1) Equivalent to address 502).

  After receiving the path establishment response, the BS 10A stores the path information between the MS 20A and the U-AGW 6-1 in the BS forwarding address management table 1000 based on the path establishment response received in SQ025 (SQ026).

  Specifically, the BS 10A registers the MSID of the MS 20A included in the path establishment response received in SQ025 in the MSID 1001 of the new entry in the BS forwarding address management table 1000 in SQ026. Also, the BS 10A registers the IP address of the U-AGW 6-1 included in the path establishment response received in SQ025 in the transfer destination IP address 1002 of the new entry.

  After receiving the path establishment response, the MS 20A transmits an address request to the HA 2 via the BS 10A and the U-AGW 6-1 (SQ028, SQ029, and SQ030). Here, the U-AGW 6-1 may transmit an address request to the HA 2 by using the IP address of the HA 2 held in advance. The address request includes an MSID indicating the MS 20A.

  After receiving the address request, HA2 transmits an authentication request to AAA3 (SQ031). The authentication request includes an MSID indicating the MS 20A.

  After receiving the authentication request, AAA3 assigns an IP address to MS 20A, and sends an authentication response including the assigned IP address to HA2 (SQ032). The authentication response includes an MSID indicating the MS 20A.

  The HA 2 updates the HA forwarding address management table 200 based on the authentication response received from the AAA 3. Specifically, the IP address of the MS 20A included in the authentication response transmitted from the AAA 3 is registered in the assigned IP address 203 of the entry in the HA forwarding address management table 200 having the MS ID 201 indicating the MS 20A (SQ033).

  With SQ033, HA2 can register the path information related to the MS 20A in the HA forwarding address management table 200 and assign an IP address to the MS 20A.

  After SQ033, HA2 generates an address notification including the IP address assigned to MS 20A, and transmits the generated address notification to U-AGW 6-1 (SQ034). The generated address notification includes the IP address of HA2 that is the transmission source of the address notification.

  After SQ034, the U-AGW 6-1 updates the U-AGW session management table 600 based on the received address notification (SQ035). Specifically, in SQ035, the U-AGW 6-1 assigns the source IP address of the address notification transmitted from the HA 2 to the transfer destination HA 604 of the entry in the U-AGW session management table 600 having the MSID 201 indicating the MS 20A. sign up.

  After SQ035, the U-AGW 6-1 transfers the address notification transmitted from the HA 2 to the MS 20A via the BS 10A (SQ036 and SQ037). By sending an address notification to the MS 20A, a session between the MS 20A and the HA 2 is established.

  After receiving the address notification, the MS 20A transmits and receives user data using the IP address included in the address notification transmitted by SQ037 as its own IP address (SQ038, SQ039, and SQ040).

  In SQ038 to SQ040, when the MS 20A transmits and receives user data, the U-AGW 6-1 acquires, for each session, the packet transfer amount in the present embodiment for the packet passing through the U-AGW 6-1. Then, the packet transfer amount 603 of the entry in the U-AGW session management table 600 indicating the MS 20A is updated with the acquired packet transfer amount (SQ041).

  Note that the U-AGW 6-1 acquires the packet transfer amount to be stored in the packet transfer amount 603 in SQ041. That is, the U-AGW 6-1 acquires, for example, the packet transfer amount per unit time in SQ041.

  After SQ041, the U-AGW 6-1 notifies the C-AGW 5 of the acquired packet transfer amount during a period designated in advance by the administrator or the like (SQ042).

  When the C-AGW 5 receives the packet transfer amount from the U-AGW 6-1, the C-AGW 5 updates the packet transfer amount 512 of the entry in the C-AGW session management table 510 indicating the MS 20A with the received packet transfer amount (SQ043). .

  The U-AGW 6-1 can hold the latest packet transfer amount in the U-AGW session management table 600 by SQ041. Also, the C-AGW 5 can hold the latest packet transfer amount of the session accommodated by each U-AGW 6 in the C-AGW session management table 510 by SQ043. Furthermore, the C-AGW 5 can perform processing for calculating a threshold value 523 in the threshold value management table 520 described later based on the latest packet transfer amount.

  Note that the U-AGW 6 or the C-AGW 5 sends all the packet transfer amounts of each U-AGW 6 in the AGW 4 via the core network 1 at a predetermined timing after SQ 042 or when an instruction is given by the administrator. You may transmit to AAA3. Accordingly, when the MS 20 communicating with the U-AGW 6 performs the initial connection process again with the HA 2 by the process shown in FIG. 13, the AAA 3 can transmit the packet transfer amount to the C-AGW 5 in SQ017. .

  FIG. 14 is a flowchart showing the U-AGW selection process 800 according to the embodiment of the present invention.

  After receiving the path establishment request in SQ020, the C-AGW 5 performs U-AGW selection processing 800 shown in FIG. 14 in SQ021.

  When the external communication interface 1 (51) of the C-AGW 5 receives the path establishment request in SQ020 (801), the communication processing process 58 of the C-AGW 5 indicates the MSID included in the received path establishment request, that is, the MS 20A. Get MSID.

  The communication processing process 58 searches the C-AGW session management table 510 using the acquired MSID as a key. As a result of the search, the communication processing process 58 acquires the packet transfer amount indicated by the packet transfer amount 512 of the entry of the C-AGW session management table 510 including the acquired MSID in the MSID 511 (802).

  After step 802, the communication processing process 58 compares the packet transfer amount acquired in step 802 with the threshold value 523 of the threshold value management table 520 in order from the upper entry. As a result of the comparison, the uppermost entry in the threshold management table 520 is extracted from the entries whose threshold stored in the threshold 523 is equal to or less than the acquired packet transfer amount.

  This is because the entries stored in the threshold management table 520 are arranged in advance so that the values stored in the threshold 523 are in descending order from the upper level. The entry extracted here is referred to as entry x below.

  The communication processing process 58 assigns the type T [x] indicated by the type 521 of the entry x to the session type of the MS 20A indicated by the path establishment request. Then, the type 515 of the entry in the C-AGW session management table 510 indicating the MS 20A is updated with a value indicating the type T [x] (803).

  In step 803, the communication processing process 58 of the C-AGW 5 assigns a type according to the packet transfer amount of the MS 20A to the session of the MS 20A. That is, the communication processing process 58 of the C-AGW 5 assigns a type to the session of the MS 20A according to the communication status of the MS 20A.

  After step 803, the communication processing process 58 specifies the type T [x] column 504 [x] of the number of active sessions 504 in the U-AGW management table 500. Then, the communication processing process 58 identifies the U-AGW number 501 of the entry with the smallest number of active sessions in the identified type T [x] column 504 [x]. Then, the identified U-AGW number 501 is selected as the U-AGW 6 that accommodates the session of the MS 20A (804).

  In step 804, the communication processing process 58 of the C-AGW 5 can select the U-AGW 6 that accommodates the least number of sessions assigned the same type as that assigned to the session of the MS 20A. That is, the communication processing process 58 uses the U-AGW 6 that accommodates the MS 20 session so that the number of sessions accommodated by each U-AGW 6 in the AGW 4 becomes equal for each type to which the MS 20 session is assigned in step 804. Can be selected. Further, this allows the communication processing process 58 to distribute the load among the plurality of U-AGWs 6 in the AGW 4.

  Note that the communication processing process 58 of the C-AGW 5 may hold in advance in the memory 54 the U-AGW number indicating the U-AGW 6 that can be selected according to the type as the identifier of the U-AGW 6 to be selected. Then, in step 804, the communication processing process 58 reads the identifier of the U-AGW 6 to be selected from the memory 54, and the identifier of the U-AGW 6 to be selected is predetermined for the type assigned to the session of the MS 20A. If it is determined, the U-AGW 6 that accommodates the session may be selected from the U-AGWs 6 to be selected.

  Thereby, the administrator or the like can determine the type of session accommodated in the predetermined U-AGW 6. For example, the administrator or the like can determine the type assigned to the user session having a large amount of packet transfer to the U-AGW 6 having very high processing performance. And C-AGW5 can distribute the load between U-AGW6 as an administrator etc. desire.

  Here, a case where the communication processing process 58 selects, for example, U-AGW 6-1 in step 804 will be described below. The communication processing process 58 registers the selected U-AGW 6-1 in the accommodation U-AGW 513 of the entry in the C-AGW session management table 510 indicating the MS 20A. Further, the communication processing process 58 registers a value indicating “Active” in the state 514 of the entry indicating the MS 20A (805).

  The communication processing process 58 of the C-AGW 5 can update the information regarding the U-AGW 6 that accommodates the session of the MS 20 </ b> A at step 805.

  After step 805, the communication processing process 58 increments the value of the column 504 [x] of the type T [x] of the number of active sessions 504 in the entry of the U-AGW management table 500 indicating the U-AGW 6-1 ( 806). For example, the communication processing process 58 increments by adding 1 to the value of the column 504 [x] of type T [x].

  The communication processing process 58 of the C-AGW 5 can maintain the number of active sessions accommodated in each U-AGW 6 by step 806 for each type.

  Further, the communication processing process 58 of the C-AGW 5 distributes the load on the U-AGW 6 for each session having a close communication state by the U-AGW selection processing 800 shown in FIG. There is little increase in load.

  FIG. 15 is a sequence diagram illustrating processing performed when an active session transitions to an idle state according to the embodiment of this invention.

  FIG. 15 shows a process performed when the session state of the MS 20A transitions from the active state to the idle state. Hereinafter, an example of processing in which the session of the MS 20A is accommodated in the U-AGW 6-1 and the MS 20A idles the session via the BS 10A will be described.

  When the MS 20A holding the session in the active state does not transmit and receive user data for a predetermined time, the MS 20A of the present embodiment autonomously transitions the state of the MS 20A to the idle state. The frequency with which the MS 20A in the idle state communicates with the BS 10A is less than the frequency with which the MS 20A in the active state communicates with the BS 10A. For this reason, the power consumption in MS20A decreases.

  Even in the idle state, communication between the MS 20A and the U-AGW 6-1 decreases, but information regarding the session of the MS 20A in the BS 10A, the C-AGW 5 and the U-AGW 6-1 is retained. That is, the idle state in the present embodiment is a state where the MS 20A and the HA 2 hardly communicate with each other through the session, but on the other hand, the session between the MS 20A and the HA 2 is maintained.

  When the MS 20A transitions to the idle state, the MS 20A transmits an idle notification to the C-AGW 5 via the BS 10A (SQ111 and SQ112). When the C-AGW 5 receives the idle notification, the C-AGW 5 transmits an idle response to the MS 20A via the BS 10A (SQ113 and SQ114).

  Note that the idle notification and the idle response include an MSID for identifying the session of the MS 20A.

  When the idle response is received, the BS 10A generates a path deletion request including the MSID indicating the session of the MS 20A that is the MS 20 that has transmitted the idle notification. Then, the generated path deletion request is transmitted to the C-AGW 5 (SQ115).

  When the path deletion request is received, the C-AGW 5 transmits a path setting change request A including the MSID included in the path deletion request to the U-AGW 6-1 (SQ116).

  The C-AGW 5 specifies an entry of the MSID 511 indicating the MSID included in the received path deletion request from the C-AGW session management table 510 in order to specify the transmission destination that transmits the path setting change request A in SQ116. To do. Then, the U-AGW 6 indicated by the accommodated U-AGW 513 in the specified entry is specified as the U-AGW 6 that is the transmission destination of the path setting change request A.

  When the path setting change request A is received, the U-AGW 6-1 updates the state 602 of the entry of the U-AGW session management table 600 indicating the MSID included in the path setting change request A to “idle” ( SQ117).

  In SQ117, the U-AGW 6-1 extracts the packet transfer amount from the packet transfer amount 603 of the entry of the U-AGW session management table 600 indicating the MSID included in the path setting change request A. Then, a path setting change response A including the extracted packet transfer amount and the MSID included in the setting change request A is generated.

After SQ117, the U-AGW 6-1 transmits the generated path setting change response A to the C-AGW 5 (SQ118) . The path setting change response A includes the packet transfer amount of the MS 20 indicated by the MSID included in the path setting change request A, that is, the packet transfer amount of the MS 20A.

  When the C-AGW 5 receives the path setting change response A, the C-AGW 5 includes the packet transfer amount 512 of the entry in the C-AGW session management table 510 indicating the MSID included in the path setting change response A in the path setting change response A. Updated according to the amount of packet transfer Further, the state 514 of the entry in the C-AGW session management table 510 indicating the MSID included in the path setting change response A is updated to “idle”.

  Further, the C-AGW 5 acquires the entry type 515 indicating the MSID included in the path setting change response A from the C-AGW session management table 510. Then, the number of active sessions 504 in the entry of the U-AGW management table 500 corresponding to the acquired type 515 and the identifier of the U-AGW 6 that is the transmission source of the path setting change response A is specified. Then, the value of the specified number of active sessions 504 is decremented (SQ119).

  The communication processing process 58 of the C-AGW 5 decrements the value of the specified number of active sessions 504, for example, by subtracting 1 from the value of the number of active sessions 504.

  The C-AGW 5 subtracts the number of sessions by the MS 20 transitioning to the idle state from the number of active sessions 504 by SQ119. Accordingly, the C-AGW 5 can perform the selection process of the U-AGW 6 illustrated in FIG. 14 based on the number of active sessions 504 that accurately indicates the session status of the MS 20. That is, the load between the U-AGW 6 in the AGW 4 can be distributed based on the latest number of active sessions 504.

  After SQ119, C-AGW5 transmits a path deletion response to BS 10A (SQ120). When receiving the path deletion response, the BS 10A deletes the entry in the BS forwarding address management table 1000 indicating the MSID included in the path deletion response (SQ121).

  The information regarding the session of the MS 20A held by the BS 10A is deleted by the SQ 121.

  FIG. 16 is a sequence diagram illustrating processing performed when an idle session according to the embodiment of this invention is activated.

  FIG. 16 shows processing performed when the session between the MS 20 and the U-AGW 6 changes from the idle state to the active state. Here, a process when the MS 20A connected to the BS 10A is activated is shown.

  When the MS 20A in the idle state resumes communication, the MS 20A transitions to the active state. At that time, the MS 20A transmits an activation notification to the C-AGW 5 via the BS 10A (SQ211 and SQ212). Note that the MS 20A includes a value (for example, MSID or IP address) for identifying the session of the MS 20A in the activation notification.

  When receiving the activation notification from the MS 20A, the C-AGW 5 transmits an activation response to the BS 10A (SQ213). The C-AGW 5 refers to the received activation notification and includes a value (for example, MSID) for identifying the session of the MS 20A in the activation response.

  When the BS 10A receives the activation response, the BS 10A transmits a path establishment request to the C-AGW 5 (SQ214). The BS 10A refers to the received activation response and includes the MSID indicating the MS 20A in the path establishment request. Also, the BS 10A includes the IP address of the BS 10A as a transmission source address in the path establishment request.

  When the C-AGW 5 receives the path establishment request, the C-AGW 5 executes U-AGW selection processing (SQ215). The U-AGW selection process in SQ215 is the same process as the U-AGW selection process in SQ021 shown in FIG. That is, the C-AGW 5 executes the process shown in FIG. 14 in SQ215.

  Note that the communication processing process 58 of the C-AGW 5 indicates that the value already stored in the entry U-AGW 513 of the entry indicating the MS 20A in the C-AGW session management table 510 indicates the U-AGW 6 selected in step 804. Otherwise, if it is determined in step 805 in SQ 215, the value already stored in the accommodation U-AGW 513 is retained in the memory 54 as a value indicating the U-AGW 6 in which the session of the MS 20A was accommodated last time.

  In step 806 in SQ 215, the C-AGW 6 adds the number of sessions of the MS 20 transitioning to the active state to the number of active sessions 504 in the U-AGW management table 500. Thereby, the C-AGW 6 can perform the U-AGW 6 selection process performed for the other MS 20 based on the number of active sessions 504 that accurately indicates the communication status of the MS 20. That is, the C-AGW 6 can distribute the load between the U-AGWs 6 in the AGW 4 based on the latest number of active sessions 504.

  Here, the case where the C-AGW 5 selects the U-AGW 6-m in the SQ 215 in the SQ 215 and holds the value indicating the U-AGW 6-1 as the U-AGW 6 accommodated in the previous time in the memory 54 in the SQ 215 is as follows. Shown in

  After SQ215, the C-AGW 5 generates a path setting change request B. Then, the C-AGW 5 transmits the generated path setting change request B to the U-AGW 6-1 that is the U-AGW 6 accommodated last time indicated by the memory 54 (SQ216).

  Note that the C-AGW 5 includes the MS-ID of the MS 20A and the transfer destination U-AGW of the MS 20A session (that is, the U-AGW 6 selected in the SQ 215) in the path setting change request B. At least the IP address and the IP address of the BS 10A are included. Specifically, the C-AGW 5 acquires the IP address of the U-AGW 6-m included in the path setting change request B from the IP address 502 of the U-AGW management table 500. Further, the C-AGW 5 acquires the IP address of the BS 10A to be included in the path setting change request B from the path establishment request received in SQ214.

  When the U-AGW 6-1 receives the path setting change request B, the U-AGW 6-1 sends the path setting change request C to the U-AGW 6-m (transfer destination U-AGW) IP address included in the path setting change request B. It transmits to AGW6-m (SQ217). Here, the U-AGW 6-1 includes at least the packet transfer amount of the MS 20A, the IP address of the BS 10A, and the IP address of the transfer destination HA of the MS 20A in the path setting change request C.

  Specifically, the U-AGW 6-1 indicates the packet transfer amount of the MS 20A included in the path setting change request C and the IP address of the HA 2 that is the transfer destination of user data of the MS 20A in the U-AGW session management table 600. Obtained from the packet transfer amount 603 and the transfer destination HA 604. Also, the U-AGW 6-1 acquires the IP address of the BS 10A to be included in the path setting change request C from the path setting change request B received in SQ216.

  When the U-AGW 6-m receives the path setting change request C, the U-AGW 6-m transmits the path setting change request D to the HA 2 according to the IP address of the HA 2 included in the path setting change request C (SQ218). The U-AGW 6-m includes at least the HA side IP address of the U-AGW 6-m, which is the transfer destination U-AGW, in the path setting change request D as the source IP address.

  When the HA 2 receives the path setting change request D, the HA 2 uses the transfer destination IP address 202 of the entry indicating the MS 20A in the HA transfer destination address management table 200 as the HA side of the U-AGW 6-m included in the path setting change request D. Update with the IP address (SQ219).

  After SQ219, HA2 transmits a path setting change response D to U-AGW6-m (SQ221). The HA 2 includes at least the MSID indicating the MS 20A in the path setting change response D.

  When the U-AGW 6-m receives the path setting change response D, the U-AGW 6-m registers information on the session to be activated in the new entry of the U-AGW session management table 600 (SQ222).

  Specifically, the U-AGW 6-m in the SQ 222 stores the MSID of the MS 20A in the MSID 601 and the value indicating “Active” in the status 602 in the new entry of the U-AGW session management table 600. The U-AGW 6-m also transmits the packet transfer amount of the MS 20A, the IP address of the transfer destination HA of the MS 20A, and the IP address of the BS 10A included in the path setting change request C received in SQ217, and the packet transfer amount 603 and the transfer destination. The data is stored in the HA 604 and the transfer destination BS 605.

  After SQ222, the U-AGW 6-m transmits a path setting change response C to the U-AGW 6-1 that is the transmission source of the path setting change request C and the session transfer source of the MS 20A (SQ223). . The U-AGW 6-m includes the MSID indicating the MS 20A in the path setting change response C.

  When receiving the path setting change response C, the U-AGW 6-1 deletes the entry indicating the session of the MS 20A from the U-AGW session management table 600 (SQ224).

  By SQ222, U-AGW6-1 can delete the information regarding the session of MS20A from the session management table 600 for U-AGW. Thereby, the U-AGW 6-1 does not accommodate the session of the MS 20A, and can stop transmission of the packet transfer amount of the session of the MS 20A to the C-AGW 5.

  Further, the SQ225 allows the U-AGW 6-m to add information related to the session of the MS 20A to the U-AGW session management table 600. Thereby, the U-AGW 6-1 can accommodate the session of the MS 20A and can start transmitting the packet transfer amount of the session of the MS 20A to the C-AGW 5.

  After SQ224, the U-AGW 6-1 transmits a path setting change response B to the C-AGW 5 (SQ225). The U-AGW 6-1 includes at least the MSID indicating the MS 20A in the path setting change response B.

  When the C-AGW 5 receives the path setting change response B, the C-AGW 5 transmits a path establishment response to the BS 10A (SQ226). Here, the C-AGW 5 transmits a path establishment response to the BS 10A that transmitted the path establishment request in SQ214.

  In SQ226, C-AGW 5 includes at least the BS side IP address of U-AGW 6-m, that is, U-AGW 6 selected in SQ 215, in the path establishment response. The C-AGW 5 acquires the BS-side IP address to be included in the path establishment response from the U-AGW management table 500 502.

  When the BS 10A receives the path establishment response, the BS 10A registers an entry indicating the session of the MS 20A in the BS forwarding address management table 1000. Specifically, the BS 10A stores the MSID included in the path establishment response in the MSID 1001 of the new entry in the BS forwarding address management table 1000. Further, the BS side IP address of U-AGW6-m included in the path establishment response is stored in the transfer destination IP address 1002 of the new entry (SQ227).

  After SQ227, the BS 10A transmits an activation response to the MS 20A (SQ228).

  By the process illustrated in FIG. 16, the C-AGW 5 can change the U-AGW 6 that accommodates the session of the MS 20 when the MS 20 transitions to the active state. That is, even when the MS 20 transitions from the idle state to the active state, the C-AGW 5 can distribute the load of the U-AGW 6 in the AGW 4 and can increase the load distribution opportunity.

  FIG. 17 is a flowchart illustrating the threshold value calculation process 900 according to the embodiment of this invention.

  The threshold value calculation process 900 may be a process that is periodically executed by the communication process 58 of the C-AGW 5 or may be a process that is executed in response to some event. The term “periodic” in this embodiment means every predetermined period such as every hour, every day, or every week. Further, the certain event may be, for example, a case where the total packet transfer amount in any U-AGW 6 of the AGW 4 increases beyond a predetermined threshold in a predetermined period.

  In general, the number of users (that is, the number of connections) connected to the BS 10 (that is, the number of connections) and the packet transfer amount vary throughout the day. For this reason, the process shown below in FIG. 17 is executed every hour.

  First, when the threshold calculation processing 900 is started, the communication processing process 58 of the C-AGW 5 clears all values stored in the threshold 523 of the threshold management table 520 to null values (901).

  After step 901, the communication processing process 58 obtains the packet transfer amount in the sessions of all the MSs 20 from the packet transfer amount 512 of the C-AGW session management table 510. Then, the communication processing process 58 holds, in the memory 54, a numerical sequence in which the packet transfer amount of each acquired session is arranged in descending order of the packet transfer amount value (902).

  After step 902, the communication processing process 58 refers to the threshold management table 520, and selects the entry having the smallest number of the type 521 from the plurality of entries for which the threshold 523 is cleared. Then, the session ratio 522 of the selected entry and the session ratios 522 of all entries whose type 521 is smaller than the type 521 of the selected entry are added to obtain the sum of the session ratios (903). Note that in the first step 903 after the threshold values 523 of all entries are cleared in step 901, an entry with type 521 of T [1] is selected, and there is no entry with a lower number than type 521. The session ratio 522 itself of the entry whose 521 is T [1] is the sum of the session ratios.

  After step 903, the communication processing process 58 multiplies the number of all MSs 20 by the [sum of session ratios] for [sum of session ratios], and rounds off the decimals to the MS ratio. Calculate as a number.

  The sum of session ratios is the sum of all values stored in the session ratio 522 column. That is, when the session ratio is indicated by a 100-minute rate, the total session ratio is 100 (%).

  The MS ratio number is a number indicating the number of sessions that are assigned to the type indicated by the entry of the selected threshold management table 520 and are included in the session having the largest packet transfer amount.

  The communication processing process 58 counts the packet transfer amount in the same order as the MS ratio number, counting from the order of the packet transfer amount in the sequence of the packet transfer amount of each session arranged in descending order in step 903. Is stored in the threshold value 523 of the entry of the threshold value management table 520 selected in (904).

  By step 904, the communication processing process 58 can assign each type according to a predetermined session ratio in the order of sessions with a large packet transfer amount. Then, the threshold value for assigning the MS 20 to each type can be reset based on the latest packet transfer amount of the MS 20.

  The communication processing process 58 repeats the processing of step 903 and step 904 until the threshold values 523 of all types 521 except type T [K] are set (905). In this embodiment, the threshold value 523 and the initial threshold value 524 of the entry indicating the type T [K] do not include values. This is because the packet transfer amount of the MS 20 assigned to the type T [K] is a value smaller than the threshold value 523 of the type T [K-1], and the C-AGW 5 has a threshold value 523 of the type T [K-1]. This is because type T [K] can be assigned to a session.

  With the processing illustrated in FIG. 17, the C-AGW 5 can periodically update the threshold value 523 of the threshold value management table 520. Thus, in the process shown in FIG. 14, for example, a type can be assigned to a session based on the communication status of each user every hour. And load distribution to U-AGW6 can be performed based on the communication condition for every hour. Accordingly, the C-AGW 5 can distribute the load on the U-AGW 6 based on the latest information.

  In addition, this invention is not limited to the Example described above, Various modifications are included. That is, the above-described embodiments have been described in detail in order to easily understand the present invention, and are not necessarily limited to those having all the configurations described.

  For example, the embodiment of the present invention may be implemented by a system comprising a plurality of C / U integrated access gateways, rather than a C / U separation type (that is, a configuration in which C-AGW 5 and U-AGW 6 are separated). Good. In this case, the plurality of tables of the C / U separation type C-AGW 5 described above are separated, each access gateway holds each table, and each access gateway transmits and receives messages, so that each table is updated. Keep in state. Then, by activating the communication processing process 58 in any of the access gateways, this embodiment can also be implemented in a C / U integrated system.

  Further, for example, in a system in which AGW 4 and HA 2 are mounted by the same device, this embodiment can be implemented by omitting message transmission / reception between AGW 4 and HA 2.

  Further, for example, the present embodiment can be implemented when the C-AGW 5 receives a path establishment request also at the time of handover when the MS 20 switches the BS 10.

  In the above-described embodiment, the U-AGW 6 acquires the packet transfer amount, and the C-AGW 5 assigns a type to each MS 20 according to the packet transfer amount. However, the U-AGW 6 of the present embodiment may acquire any value as long as it can acquire a value that quantitatively indicates the communication status of each MS 20.

  For example, the U-AGW 6 may acquire the communication time of the session by the MS 20 instead of the packet transfer amount, or may acquire the average value of the daily communication time. And C-AGW5 may assign a type to MS20 by the average value of daily communication time.

  In addition, each program (for example, a program for executing the communication processing process 58 of the C-AGW 5) that realizes each function described above, and information of each table (for example, the session management table 510 for C-AGW). Can be stored not only in a memory but also in a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

  In addition, control lines and information lines in each apparatus are described as necessary for explanation, and not all control lines and information lines to be mounted are necessarily described.

  According to this embodiment, when the C-AGW 5 selects the U-AGW 6 that communicates with the MS 20, the C-AGW 5 assigns a type to the session according to the communication status of the packet transfer of the session, and selects the U-AGW 6 according to the type. The load by users who are in close communication with each U-AGW 6 is distributed. This prevents the load from being concentrated on a specific U-AGW 6 in the AGW 4.

  Further, when the session state transitions from the idle state to the active state, the C-AGW 5 selects the U-AGW 6 according to the communication status, and sets the path between the selected U-AGW 6 and the MS 20 again. Thereby, the load distribution opportunity of U-AGW6 in AGW4 can be increased. Thereby, according to the present embodiment, it is possible to shorten the time during which the load concentrates on the specific U-AGW 6 in the AGW 4.

1 Core network 2 Home agent (HA)
3 Authentication server (AAA)
4 Access gateway (AGW)
5 C-AGW
6 U-AGW
7 Access network 8 Internet or public communication network 10 Wireless base station (BS)
20 Mobile (MS)
200 HA transfer destination address management table 500 U-AGW management table 510 C-AGW session management table 520 Threshold management table 600 U-AGW session management table 1000 BS transfer destination address management table

Claims (15)

A communication system comprising: a base station that communicates wirelessly with a terminal; a plurality of gateways that communicate with the terminal via the base station; and an agent device that communicates with the terminal via each gateway,
The plurality of gateways are:
With processor, memory, and network interface,
Connected to each gateway via the network interface;
Communicating with the terminal by accommodating a session established between the terminal and the agent device;
The first gateway is
A threshold management table including communication information indicating a communication status in the session accommodated by each gateway, and values indicating a plurality of types assigned to the session according to the communication information;
A gateway management table that indicates the number of sessions accommodated by each gateway for each type assigned to the session;
When receiving a path establishment request including designation of a session held by the terminal that starts communication, the communication information in the session designated by the path establishment request is acquired,
According to the acquired communication information and the threshold management table, assign the type to the session specified by the path establishment request,
A communication system, wherein a gateway accommodating a session specified by the path establishment request is selected according to the assigned type and the gateway management table. A communication system according to claim 1,
If the session state is the first active state, the session is accommodated in a second gateway;
The first gateway is
If the session state transitions from the first active state to the idle state, a path deletion request including the designation of the session to transition to the idle state is received;
When the path deletion request is received , the gateway management table is updated based on the path deletion request by subtracting the number of sessions transitioning to the idle state from the number of sessions accommodated by the second gateway. And
If the session state transitions from the idle state to a second active state, the path establishment request is received;
When a third gateway is selected as the gateway that accommodates the session specified by the path establishment request, the second gateway is set to the number of sessions accommodated by the third gateway based on the path establishment request. A communication system , wherein the gateway management table is updated by adding the number of sessions transitioning to an active state . A communication system according to claim 2, comprising:
Each gateway has a session management table including the communication information in a session accommodated by the gateway,
When the third gateway is selected, the second gateway deletes the communication information in the session specified by the path establishment request from the session management table of the second gateway,
When the third gateway is selected, the third gateway adds communication information in the session specified by the path establishment request to the session management table of the third gateway. Communications system. A communication system according to any one of claims 1 to 3, wherein
The first gateway has a control session management table including the communication information in a session accommodated by each gateway,
Each gateway transmits communication information in a session accommodated by the gateway to the first gateway at a predetermined timing.
The communication system, wherein the first gateway stores communication information transmitted from each gateway in the control session management table. A communication system according to claim 4, comprising:
The threshold management table includes a threshold of the communication information for assigning each type to the session, and a predetermined session ratio indicating the number of the sessions to which each type is assigned,
The first gateway is
Obtain each communication information included in the control session management table,
In accordance with the session ratio, the thresholds are extracted from the acquired communication information so that the types can be assigned to the terminals.
A communication system, wherein each threshold value included in the threshold management table is updated with each extracted threshold value. A communication system according to any one of claims 1 to 3, wherein
The first gateway establishes the path so that the number of the sessions accommodated in each gateway and assigned the same type as the assigned type is equal based on the gateway management table. A communication system characterized by selecting a gateway accommodating a session specified by a request. A communication system according to any one of claims 1 to 3, wherein
The first gateway is
Holds gateway identification information that can be selected according to the assigned type,
A communication system, wherein a gateway accommodating a session specified by the path establishment request is selected according to the assigned type, the gateway management table, and the identification information. A communication system according to any one of claims 1 to 3, wherein
The communication information includes a packet amount per unit time of a packet communicated between the terminal and each gateway,
Each said gateway acquires the packet amount per said unit time of the packet communicated with the said terminal, The communication system characterized by the above-mentioned. A base station communicating by the terminal and the radio, there a plurality of gateways and the communication method according to a communication system and a agent device that communicates with the terminal through the respective gateway that communicates with the terminal through the base station And
The plurality of gateways are:
With processor, memory, and network interface,
Connected to each gateway via the network interface;
Communicating with the terminal by accommodating a session established between the terminal and the agent device;
The first gateway is
A threshold management table including communication information indicating a communication status in the session accommodated by each gateway, and values indicating a plurality of types assigned to the session according to the communication information;
A gateway management table that indicates the number of sessions accommodated by each gateway for each type assigned to the session;
The method
When the first gateway receives a path establishment request including a designation of a session held by the terminal that starts communication, obtains the communication information in the session designated by the path establishment request;
The first gateway assigns the type to a session specified by the path establishment request according to the acquired communication information and the threshold management table;
The communication method, wherein the first gateway selects a gateway that accommodates a session specified by the path establishment request according to the assigned type and the gateway management table. The communication method according to claim 9, comprising:
The session is accommodated in a second gateway if the session state is the first active state;
The method
The first gateway receives a path deletion request including designation of the session to transition to the idle state when the session state transitions from the first active state to the idle state;
When the first gateway receives the path deletion request, the number of sessions that transition to the idle state is subtracted from the number of sessions accommodated by the second gateway based on the path deletion request. , Update the gateway management table,
The first gateway receives the path establishment request when the session state transitions from the idle state to a second active state;
When the third gateway is selected as the gateway that accommodates the session specified by the path establishment request, the first gateway is configured to store the session accommodated by the third gateway based on the path establishment request. The gateway management table is updated by adding the number of sessions that transition to the second active state to the number, and updating the gateway management table. The communication method according to claim 10, comprising:
Each gateway has a session management table including the communication information in a session accommodated by the gateway,
The method
When the third gateway is selected, the second gateway deletes the communication information in the session specified by the path establishment request from the session management table of the second gateway,
When the third gateway is selected, the third gateway adds communication information in the session specified by the path establishment request to the session management table of the third gateway. Communication method. A communication method according to any one of claims 9 to 11, comprising:
The first gateway has a control session management table including the communication information in a session accommodated by each gateway,
The method
Each gateway transmits communication information in a session accommodated by the gateway to the first gateway at a predetermined timing.
The communication method, wherein the first gateway stores communication information transmitted from each gateway in the control session management table. A communication method according to claim 12, comprising:
The threshold management table includes a threshold of the communication information for assigning each type to the session, and a predetermined session ratio indicating the number of the sessions to which each type is assigned,
The method
The first gateway acquires each communication information included in the control session management table,
The first gateway extracts the thresholds from the acquired communication information so that the types can be assigned to the terminals according to the session ratios,
The communication method, wherein the first gateway updates each threshold included in the threshold management table with each extracted threshold. A communication method according to any one of claims 9 to 11, comprising:
The method
Based on the gateway management table, the path establishment is performed so that the number of the sessions in which the first gateway is accommodated in each gateway and is assigned the same type as the assigned type is the same. A communication method comprising selecting a gateway that accommodates a session specified by a request. A communication method according to any one of claims 9 to 11, comprising:
The method
The first gateway holds gateway identification information that can be selected according to the assigned type;
The communication method, wherein the first gateway selects a gateway that accommodates a session specified by the path establishment request according to the assigned type, the gateway management table, and the identification information.

Images