Communication control device and communication control method

Abstract

A communication control device (10) comprises: a detection unit (14a) that detects whether each user terminal device (20), the accommodation destination of which is switched from a first edge router (22a) to a second edge router (22b), is busy; and a reacquisition control unit (14b) that performs control so as to block a telephone path of a user terminal device (20), which is other than the busy user terminal detected by the detection unit (14a) and is not busy, and reacquire the IP address of the user terminal device (20) which is not busy.

Description

Communication control device and communication control method

[0001] The present invention relates to a communication control device and a communication control method.

[0002] For maintenance purposes, carriers may need to switch edge routers that accommodate user terminals. When switching edge routers, the configuration information for the users currently accommodated is deleted from the edge router from which the switch is made, and then the same information is input to the edge router to which the switch is made.

[0003] As a conventional technique, for example, a technique has been proposed in which, when an edge router is relocated for maintenance, an edge control system works in conjunction with a DHCP (Dynamic Host Configuration Protocol) server system to reduce the impact on user communications services.

[0004] International Publication No. 2021 / 095226

[0005] RFC3665 “Session Initiation Protocol (SIP) Basic Call Flow Examples“<https: / / datatracker.ietf.org / doc / html / rfc3665>

[0006] However, with conventional technology, it has been difficult to switch edge routers during a call without interrupting the call. For example, when switching edge routers by re-acquiring an IP address, it takes time for the user terminal to independently re-acquire an IP address, and communication may be interrupted during that time.

[0007] In order to solve the above-mentioned problems and achieve the objectives, the communication control device of the present invention is characterized by including a detection unit that detects whether each user terminal whose accommodation is switched from a first edge router to a second edge router is in a call, and a control unit that, based on the result of detection by the detection unit, blocks the telephone path of the user terminal that is not in a call and controls the user terminal that is not in a call to obtain an IP address.

[0008] According to the present invention, it is possible to advantageously switch edge routers during a call without interrupting the call.

[0009] FIG. 1 is a diagram illustrating an example of the overall configuration of a system according to a first embodiment. FIG. 2 is a diagram illustrating an example of the overall configuration of a system according to the first embodiment. FIG. 3 is a block diagram illustrating the functional configuration of a communication control device according to the first embodiment. FIG. 4 is a diagram illustrating a user information DB. FIG. 5 is a sequence diagram illustrating an example of the processing flow of the communication control device according to the first embodiment. FIG. 6 is a block diagram illustrating the functional configuration of a communication control device according to a second embodiment. FIG. 7 is a sequence diagram illustrating an example of the processing flow of the communication control device according to the second embodiment. FIG. 8 is a sequence diagram illustrating an example of the processing flow of the communication control device according to a third embodiment. FIG. 9 is a sequence diagram illustrating an example of the processing flow of the communication control device according to the third embodiment. FIG. 10 is a sequence diagram illustrating an example of the processing flow of the communication control device according to the third embodiment. FIG. 11 is a diagram illustrating a computer that executes a program.

[0010] The present invention will be described below through embodiments, but the following embodiments do not limit the scope of the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0011] <First Embodiment> (1-1. Overall Configuration) In the first embodiment, a communication control device 10 acquires user information during a call and prevents the acquisition of the IP address of the user during the call. FIGS. 1 and 2 are diagrams illustrating an example of the overall configuration of a system according to the first embodiment. As shown in FIGS. 1 and 2, the system according to the first embodiment includes a communication control device 10, a user terminal 20, a DHCP server 21, a first edge router 22a, and a second edge router 22b.

[0012] The communication control device 10 is a device that centrally manages multiple communication devices and is a network controller that has the function of inputting predetermined settings to communication devices such as edges. In the first embodiment, the communication control device 10 controls a first edge router 22a and a DHCP server 21. Specifically, the communication control device 10 controls the first edge router 22a, which is physically and logically connected to a user terminal 20 as multiple communication devices, and the DHCP server 21, which is physically and logically connected to the user terminal 20.

[0013] The user terminal 20 is a terminal device used by a user. For example, the user terminal 20 is a mobile phone, a smartphone, a tablet terminal, a personal computer, etc. Furthermore, when the user terminal 20 receives a Force renew from the DHCP server 21, it transmits a DHCP Discover, which is a search message of the DHCP server 21. Although one user terminal 20 is illustrated in FIG. 1 , multiple user terminals may be used.

[0014] The DHCP server 21 assigns an address to the user terminal 20. For example, when the DHCP server 21 receives a DHCP Discover from the user terminal 20, it assigns an address to the user terminal 20. The DHCP server 21 also holds a DB that manages user information, and communicates with the user terminal 20 after identifying the user.

[0015] The first edge router 22a is the edge router from which the switch is made, and the second edge router 22b is the edge router to which the switch is made. Note that the numbers of communication control devices 10, user terminals 20, DHCP servers 21, and edge routers 22 installed in the system are not limited to those shown in FIGS. 1 and 2 .

[0016] (Problems When Switching Edge Routers in the Past) In conventional edge router switching methods, if a user is on a call when switching, the call may be interrupted. For example, if a DHCP server that prompts a user to reacquire an IP address sends a force renew message that prompts the user terminal to reacquire an IP address, the user terminal may be disconnected from the call due to the reacquisition of an IP address.

[0017] Therefore, the communication control device 10 according to the first embodiment outputs an instruction to the DHCP server 21 to inhibit the acquisition of an IP address for the user terminal 20 in the middle of a call, thereby preventing the call from being disconnected.

[0018] (1-2. Processing Executed by the Communication Control Device 10) Here, the processing executed by the communication control device 10 will be described. FIG. 1 illustrates the case where a call is in progress, and FIG. 2 illustrates the case where the call has ended and the case where no call is in progress. Specifically, as shown in FIG. 1, the communication control device 10 notifies the first edge router 22a to enable Netflow. Next, the communication control device 10 acquires information on the user terminal 20 (here, the description will be given using an example of "user A" who is in a call) output from the first edge router 22a and detects that user A is in a call. Then, the communication control device 10 notifies the DHCP server 21 to suppress force renew for the user who is in a call, so that an IP address will not be reacquired because user A is in a call.

[0019] 2, the communication control device 10 notifies the first edge router 22a to enable Netflow. Next, for example, the communication control device 10 acquires information about the user's terminal 20 (here, an example is given of "User B" who is not currently on a call) output from the first edge router 22a and detects that User B is not currently on a call. The communication control device 10 then outputs User B's configuration information to the second edge router 22b and instructs the DHCP server 21 to perform a force renew. The DHCP server 21 then assigns an IP address to User B's terminal device 20, thereby switching the edge router from the first edge router 22a to the second edge router 22b.

[0020] That is, the communication control device 10 detects whether the user is on a call, and if so, prevents the re-acquisition of an IP address, and if not, prompts the user terminal 20 to re-acquire an IP address. This allows the communication control device 10 to switch edge routers without disconnecting the active call, thereby reducing the impact on the user.

[0021] (1-3. Functional configuration of the communication control device 10) Next, the functional configuration of the communication control device 10 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the functional configuration of the communication control device 10 according to the first embodiment. As shown in Fig. 3, the communication control device 10 according to the first embodiment has a communication unit 11, an input unit 12, an output unit 13, a control unit 14, and a storage unit 15.

[0022] The communication unit 11 is realized by a network interface card (NIC) or the like, and controls communication via a telecommunication line such as a local area network (LAN) or the Internet. The communication unit 11 is connected to the network via a wired or wireless connection as necessary, and can transmit and receive information bidirectionally. For example, the communication unit 11 according to this embodiment realizes communication between the communication control device 10, the user terminal 20, the DHCP server 21, and the edge router 22.

[0023] The input unit 12 inputs various types of information to the communication control device 10. The input unit 12 is, for example, a mouse or a keyboard, and receives input of setting information and the like to the communication control device 10.

[0024] The output unit 13 outputs various information from the communication control device 10. The output unit 13 is, for example, a display, and outputs setting information stored in the communication control device 10, etc.

[0025] The storage unit 15 is realized by, for example, a semiconductor memory element such as a random access memory (RAM) or a flash memory, or a storage device such as a hard disk drive (HDD), a solid state drive (SSD), or an optical disk. Various programs and various data are stored in the storage unit 15. The storage unit 15 has a user information DB 15a and a traffic data DB 15b.

[0026] The user information DB 15a stores user information and data related to the router being used. FIG. 4 is a diagram illustrating the user information DB. The user information DB 15a stores data related to whether or not a user terminal is in a call. As shown in FIG. 4, the user information DB 15a stores a "user name," a "router being used," and a "status" in association with each other. Here, the stored "user name" is information that identifies a user who is using an edge router. The "router being used" is information that identifies an edge router being used by a user who is in a call. The "status" is information that identifies whether or not a user is in a call.

[0027] 4, the user information DB 15a stores "user A, first edge router, in a call" and "user B, second edge router, not in a call" as "user name, edge router in use, status." That is, the user information DB 15a stores that "user A" is using the "first edge router" and is in a call, and that "user B" is using the "second edge router" and is in a not-in-a-call state.

[0028] The communication control device 10 notifies the edge router 22b, which is the switching destination, to enable Netflow. The communication control device 10 collects information about users who are in a call (for example, SUB-IF information that transmits RTP traffic data) using Netflow, and stores in the user information DB 15a whether the user is in a call or not.

[0029] The traffic data DB 15b stores a log of communications in a large-scale real network that is not a sandbox. The traffic data DB 15b stores information on the source and destination of data in communications. For example, the traffic data DB 15b may store 5-tuple information of IP packets or statistical information such as the communication volume for each flow.

[0030] Next, returning to Fig. 3, the control unit 14 of the communication control device 10 will be described. The control unit 14 has an internal memory for storing programs that define various processing procedures and required data, and executes various processes using these. Here, the control unit 14 is, for example, an electronic circuit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), or an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control unit 14 has a detection unit 14a and a reacquisition control unit 14b.

[0031] The detection unit 14a detects whether the terminal 20 of each user whose accommodation is switched from the first edge router 22a to the second edge router 22b is in a call. For example, the detection unit 14a notifies the edge router 22a from which the switching is made to enable Netflow, and collects user information about the user who is in a call (e.g., SUB-IF information that transmits RTP traffic data) using Netflow. Then, the detection unit 14a uses the collected information to detect whether the user is in a call, and stores the information about the user who is in a call in the user information DB 15a.

[0032] The reacquisition control unit 14b blocks telephone routes for user terminals that are not currently in a call other than the user terminal 20 currently in a call detected by the detection unit 14a, and controls the reacquisition of IP addresses for the user terminals 20 that are not currently in a call. For example, the reacquisition control unit 14b reads user information stored in the user information DB 15a and notifies the DHCP server 21 to suppress force renew for users currently in a call, and notifies the source edge router 22a, for the user terminals 20 that are not currently in a call, to block telephone routes for each VLAN of the user using an access list. Then, the reacquisition control unit 14b inputs user setting information for the user terminals 20 that are not currently in a call into the destination edge router 22b and instructs the DHCP server 21 to perform force renew.

[0033] (1-4. Flow of Communication Control Processing) Here, the flow of communication control processing according to the first embodiment will be described in detail with reference to Fig. 5. Fig. 5 is a sequence diagram showing an example of the flow of communication control processing according to the first embodiment.

[0034] 5, the communication control device 10 notifies the edge router 22a of the switching source to enable Netflow (step S101). For example, the communication control device 10 notifies the first edge router 22a to enable Netflow for the user currently in communication. Then, the edge router 22a of the switching source that has received the notification from the communication control device 10 outputs information about the user currently in communication via Netflow to the traffic data DB 15b (step S102).

[0035] Next, the traffic data DB 15b, which has received the user information of the user who is currently on a call, notifies the communication control device 10 of the update of the user information (step S103). The communication control device 10, which has received the notification, acquires the user information (step S104) and notifies the DHCP server 21 to suppress force renew for the user who is currently on a call (step S105). For example, when the communication control device 10 acquires information that user A is currently on a call, it notifies the DHCP server 21 that it will not acquire an IP address. The processes from step S101 to step S105 update the information every few tens of seconds.

[0036] Next, if there is no notification of a second suppression of the force renew suppression within a certain time period (step S105), the communication control device 10 notifies the switching source edge router 22a to block the telephone route for each VLAN of the user using an access list (step S106). For example, the suppression of force renew is timer-set, and if there is no notification of a second suppression within a certain time period, the suppression of force renew is automatically released.

[0037] Next, the communication control device 10 inputs the user setting information to the edge router 22b of the switching destination (step S107). For example, when the communication control device 10 acquires information that the call of user A has ended, the communication control device 10 outputs the information of user A to the second edge router 21b.

[0038] Next, the communication control device 10 instructs the DHCP server 21 to perform a force renew (step S108). The DHCP server 21, which has received the notification from the communication control device 10, notifies the original edge router 22a of the force renew (step S109). Then, the original edge router 22a notifies the user terminal 20 of the force renew (step S110).

[0039] The user terminal 20 notifies the switching destination edge router 22b of DHCP Discover (step S111), and the switching destination edge router 22b notifies the DHCP server 21 of DHCP Discover (step S112). For example, in order to switch from the first edge router 21a to the second edge router 21b, the user terminal 20 requests the DHCP server 21 to reacquire an IP address.

[0040] The DHCP server 21, which has received the request from the edge router 22b of the switching destination, notifies the user terminal 20 that a DHCP IP address will be assigned (step S113).

[0041] The communication control device 10 collects the traffic volume for each sub-interface in Netflow from the edge router 22a from which the switch is made, and when all of the traffic volumes become zero, the communication control device 10 is notified by SNMP (Simple Network Management Protocol) (step S114). For example, the communication control device 10 is notified by SNMP that the number of users using the edge router 22a from which the switch is made has become zero.

[0042] Then, upon receiving the notification that there are no users using the original edge router 22a, the communication control device 10 notifies the original edge router 22a to stop Netflow (step S115). For example, the communication control device 10 notifies the original edge router 22a to stop collecting user data. Through the above process, the communication control device 10 switches the edge router.

[0043] (1-5. Effects of Embodiment 1) In embodiment 1, the communication control device 10 detects whether each user terminal 20 whose accommodation is switched from the first edge router 22a to the second edge router 22b is in a call, blocks telephone routes for user terminals that are not in a call other than the detected user terminals that are in a call, and controls the user terminals that are not in a call to re-acquire IP addresses. This allows the communication control device 10 to switch edge routers without interrupting a call in progress. This allows the communication control device 10 to switch edge routers without disconnecting calls in progress, thereby reducing the impact on users.

[0044] Furthermore, by enabling Netflow, the communication control device 10 can accurately detect the user's call status and switch the edge router from the user who is not in a call, thereby appropriately preventing the user's call from being disconnected.

[0045] Furthermore, before switching the edge router, the communication control device 10 detects the user's call status and instructs the DHCP server 21 to suppress force renew for the user terminal 20 that is currently on a call, thereby appropriately preventing the user's call from being disconnected.

[0046] <Embodiment 2> (2-1. Overview of Embodiment 2) In the first embodiment, an example was described in which edge router switching was performed by acquiring user information from the edge router 22a from which the switching is performed and determining whether or not a call is in progress, but the disclosed communication control device 10 can determine whether or not a call is in progress based on the CoS (Class of Service) value of each user by cooperating with an external server. Therefore, in the second embodiment, an example will be described in which whether or not a call is in progress based on the CoS value of each user is determined and edge router switching is performed.

[0047] In the second embodiment, the communication control device 10 cooperates with a subscriber aggregation device 23, which is an external server. The subscriber aggregation device 23 has a function of determining whether a user is on a call based on the traffic CoS value of each user. When the subscriber aggregation device 23 detects that a user is on a call, it notifies the communication control device 10.

[0048] (2-2. Processing Executed by the Communication Control Device 10) Here, the processing executed by the communication control device 10 will be described. Specifically, the communication control device 10 notifies the subscriber aggregation device 23 to enable a call in-progress notification function. For example, the notification function of the subscriber aggregation device 23 is a function that detects whether a user is on a call or not based on the traffic CoS value for each user. Next, the communication control device 10 acquires information about the user terminal 20 output from the subscriber aggregation device 23 and detects that the user is on a call.

[0049] Next, the subscriber aggregation device 23, which has received the notification to enable the notification function, notifies the traffic data DB 15b of the call status of each user. The traffic data DB 15b, which has received information on the call status of each user from the subscriber aggregation device 23, notifies the communication control device 10 of the update information. The communication control device 10, which has received the notification, acquires information on each user, and if the user is in a call, notifies the DHCP server 21 to suppress force renew. On the other hand, if the user is not in a call, the communication control device 10 instructs the DHCP server 21 to perform force renew. Then, the DHCP server 21 assigns an IP address to the user terminal 20, thereby switching the edge router from the first edge router 21a to the second edge router 21b.

[0050] In other words, the communication control device 10 cooperates with the subscriber aggregation device 23, which is an external server, to detect whether the user is on a call, and if so, prevents the user terminal 20 from re-acquiring an IP address, and if not, prompts the user terminal 20 to re-acquire an IP address. This allows the communication control device 10 to switch edge routers without disconnecting the call, thereby reducing the impact on the user.

[0051] (2-3. Structural Functions of the Communication Control Device 10) Next, the structural functions of the communication control device 10 will be described with reference to Fig. 6. Fig. 6 is an example of a block diagram showing the functional configuration of the communication control device 10 according to the second embodiment. As shown in Fig. 6, the communication control device 10 according to the second embodiment has a communication unit 11, an input unit 12, an output unit 13, a control unit 14, and a storage unit 15.

[0052] 6, the communication control device 10 according to the second embodiment has functions equivalent to those of the communication unit 11, input unit 12, output unit 13, user information DB 15a of the storage unit 15, and traffic data DB 15b described in FIG. 3, and therefore detailed description thereof will be omitted. Here, the detection unit 14a of the control unit 14, the reacquisition control unit 14b, and the subscriber aggregation information DB 15c of the storage unit 15, which are different from those of the first embodiment, will be described.

[0053] The subscriber aggregation information DB 15c stores data regarding whether or not a user is on a call. The subscriber aggregation information DB 15c stores a "user name" and a "CoS value" in association with each other. The "user name" is information that identifies a user who is on a call. The "CoS value" is a value that represents the priority of communication that can be set in frames received and transmitted via Ethernet (registered trademark). The "CoS value" in the second embodiment is a value that identifies whether or not a user is on a call.

[0054] The detector 14a detects whether the terminal 20 of each user whose accommodation is switched from the first edge router 22a to the second edge router 22b is in a call. For example, the detector 14a notifies the subscriber aggregation device 23 to enable a call notification function, and collects user information (e.g., traffic CoS value for each user) of the user who is in a call using the notification function. The detector 14a then uses the collected information to detect whether the user is in a call and stores the information indicating whether the user is in a call in the subscriber aggregation information DB 15c.

[0055] The reacquisition control unit 14b controls the reacquisition of IP addresses for user terminals 20 that are not currently in a call. For example, the reacquisition control unit 14b reads user information stored in the subscriber aggregation information DB 15c and notifies the DHCP server 21 to suppress force renew for users who are currently in a call, and for user terminals 20 that are not currently in a call, notifies the source edge router 22a to block the telephone route for each user's VLAN using an access list. Then, the reacquisition control unit 14b inputs user setting information for user terminals 20 that are not currently in a call into the destination edge router 22b and instructs the DHCP server 21 to perform force renew.

[0056] (2-4. Flow of Communication Control Processing) Here, the flow of communication control processing according to the second embodiment will be described in detail with reference to Fig. 7. Fig. 7 is a sequence diagram showing an example of the flow of communication control processing according to the second embodiment.

[0057] 7, the communication control device 10 notifies the subscriber aggregation device 23 to enable a call-in-progress notification function (step S201). For example, the communication control device 10 notifies the subscriber aggregation device 23 that the notification function of the subscriber aggregation device 23 is a function for detecting whether a user is on a call or not based on the traffic CoS value of each user. Then, upon receiving the notification from the communication control device 10, the subscriber aggregation device 23 notifies the traffic data DB 15b of the call status of each user (step S202).

[0058] Next, the traffic data DB 15b that has received the user information of the user in the call notifies the communication control device 10 of the update of the user information (step S203). Then, the communication control device 10 that has received the notification acquires the user information (step S204) and notifies the DHCP server 21 to suppress force renew for the user in the call (step S205). For example, when the communication control device 10 acquires information that the user is in the call, it notifies the DHCP server 21 that it will not acquire an IP address. The processes from step S201 to step S205 update the information every few tens of seconds.

[0059] Next, if there is no notification of a second suppression of the force renew suppression within a certain time period (step S205), the communication control device 10 notifies the edge router 22a of the switching source to block the telephone route for each VLAN of the user by using an access list (step S206). For example, the suppression of force renew is set by a timer, and if there is no notification of a second suppression within a certain time period, the suppression of force renew is automatically released.

[0060] Next, the communication control device 10 inputs the user setting information to the edge router 22b of the switching destination (step S207). For example, when the communication control device 10 acquires information that the call of user A has ended, the communication control device 10 outputs the information of user A to the second edge router 21b.

[0061] Next, the communication control device 10 instructs the DHCP server 21 to perform a force renew (step S208). The DHCP server 21, which has received the notification from the communication control device 10, notifies the original edge router 22a that it will perform a force renew (step S209). Then, the original edge router 22a notifies the user terminal 20 of the force renew (step S210).

[0062] The user terminal 20 notifies the switching destination edge router 22b of DHCP Discover (step S211), and the switching destination edge router 22b requests DHCP Discover from the DHCP server 21 (step S212). For example, in order to switch from the first edge router 21a to the second edge router 21b, the user terminal 20 notifies the DHCP server 21 of reacquisition of an IP address.

[0063] The DHCP server 21, which has received the request from the edge router 22b of the switching destination, notifies the user terminal 20 that a DHCP IP address will be assigned (step S213).

[0064] The communication control device 10 notifies the edge router 22a of the source of switching to enable Netflow (step S214). Next, the communication control device 10 collects the traffic volume for each sub-interface in Netflow from the edge router 22a of the source of switching, and is notified by SNMP when all the traffic volumes have become zero (step S215). For example, the communication control device 10 is notified by SNMP that the number of users using the edge router 22a of the source of switching has become zero.

[0065] Then, upon receiving the notification that there are no users using the original edge router 22a, the communication control device 10 notifies the original edge router 22a to stop Netflow (step S216). For example, the communication control device 10 notifies the original edge router 22a to stop collecting user data. Through the above process, the communication control device 10 switches the edge router.

[0066] (2-5. Effects of Embodiment 2) In embodiment 2, the communication control device 10 detects from the subscriber aggregation device 23, which is an external server, whether or not each user terminal 20 whose accommodation is being switched from the first edge router 22a to the second edge router 22b is in a call, blocks the telephone paths of user terminals other than the detected user terminal that are not in a call, and controls the user terminals that are not in a call to re-acquire IP addresses. This allows the communication control device 10 to switch edge routers without interrupting a call. This allows the communication control device 10 to switch edge routers without disconnecting the call, thereby reducing the impact on users.

[0067] <Embodiment 3> (3-1. Overview of Embodiment 3) In the above-mentioned embodiment 2, an example has been described in which the communication control device 10 acquires information on each user currently on a call from the subscriber aggregation device 23. However, the disclosed communication control device 10 may also be configured so that the subscriber aggregation device 23 restarts the ONU (Optical Network Unit) and re-acquires an IP address. Therefore, in embodiment 3, an example will be described in which the subscriber aggregation device 23 restarts the ONU and re-acquires an IP address.

[0068] (Processing Executed by Communication Control Device 10) Here, the processing executed by the communication control device 10 will be described. Specifically, the communication control device 10 notifies the subscriber aggregation device 23 to enable the functions of the subscriber aggregation device 23. The subscriber aggregation device 23 has a function of detecting whether a call is in progress based on the CoS value of each user, and restarting the ONU if the user is not in progress. Here, the ONU refers to an optical line termination device installed at a subscriber's home in an optical subscriber line network.

[0069] Next, the subscriber aggregation device 23, which has received a notification from the communication control device 10 that the function has been enabled, detects that the user using the user terminal 20 is on a call. Then, the subscriber aggregation device 23 notifies the user terminal 20 that an IP address will not be obtained because the user terminal 20 is on a call.

[0070] Next, when the subscriber aggregation device 23 receives a notification from the communication control device 10, if packets with a specific CoS value are not output from the user terminal 20 for a certain period of time, it detects that the user is not making a call and notifies the user terminal 20 to restart the ONU.

[0071] Then, the user terminal 20, which has been notified by the subscriber aggregation device 23 of the ONU restart, requests the source edge router 22a to acquire an IP address. Next, the source edge router 22a notifies the destination edge router 22b of the acquisition of an IP address. Finally, the source edge router 22a assigns an IP address to the user terminal 20, thereby switching the edge router from the source edge router 22a to the destination edge router 22b.

[0072] That is, the communication control device 10 notifies the subscriber aggregation device 23 to enable the function, and the subscriber aggregation device 23 that has received the notification notifies the user terminals 20 that are not in a call to restart the ONU, thereby switching the edge router. In this way, the communication control device 10 switches the edge router, and provides a communication control device 10 in which calls are not disconnected.

[0073] (3-2. Functional Configuration of Third Embodiment) The following describes the functional configuration of the communication control device 10. The communication control device 10 according to the third embodiment has the same functions as the communication unit 11, input unit 12, output unit 13, control unit 14, and storage unit 15 described in FIGS. 3 and 6, and therefore detailed description thereof will be omitted.

[0074] (3-3. Processing Flow of Embodiment 3) Here, the flow of communication control processing according to embodiment 3 will be described in detail with reference to Fig. 8 to Fig. 10. Fig. 8 to Fig. 10 are sequence diagrams each showing an example of the flow of communication control processing according to embodiment 3.

[0075] 8, the communication control device 10 notifies the subscriber aggregation device 23 to enable the function of the subscriber aggregation device 23 (step S301). For example, the function of the subscriber aggregation device 23 is to detect whether a call is in progress based on the traffic CoS value of each user, and if a packet with a specific CoS value is not output from the user terminal 20 for a certain period of time, to detect that a call is not in progress and to restart the ONU of each user.

[0076] Next, the subscriber aggregation device 23, which has received a notification from the communication control device 10 to enable the function, notifies the user terminals 20 that are not currently in a call to restart the OUN (step S302). The communication control device 10 inputs the user setting information into the edge router 22b, which is the switching destination (step S301.1).

[0077] Upon receiving notification from the subscriber aggregation device 23 that the OUN will be restarted, the user terminal 20 requests DHCP Discover from the subscriber aggregation device 23 (step S303). Next, the user terminal 20 notifies the subscriber aggregation device 23 and the original edge router 22a of DHCP Discover (steps S304 and S305). The original edge router 22a then notifies the destination edge router 22b of DHCP Discover (step S305). For example, the user terminal 20 requests acquisition of an IP address in order to switch from the first edge router 21a to the second edge router 21b.

[0078] Then, the switching destination edge router 22b, which has received the notification from the switching source edge router 22a, assigns an IP address to the user terminal 20 (step S306).

[0079] 9 and 10, a method for confirming that the ONU of the user terminal 20 has restarted and that the edge router switching has been completed will be described. As shown in Fig. 9, when the DHCP server 21 receives a request from the switching destination edge router 22b and assigns an IP address to the user terminal 20 (step S306), the operator checks the OUN status of all user terminals and checks whether the OUN has restarted (step S307), thereby confirming that the edge router has been switched.

[0080] 10, the communication control device 10 may also notify the subscriber aggregation device 23 of a request to confirm the status of each user (step S308). For example, upon receiving the notification of the status of each user from the communication control device 10, the subscriber aggregation device 23 confirms the status of each user using a CLI (Command Line Interface) with the user terminal 20 (step S309). Then, the user terminal 20 uses the CLI to collect the ONU status of each user and responds to the subscriber aggregation device 23 (step S310). For example, steps S309 and S310 can be automated using Ansible (registered trademark) plaubook.

[0081] Finally, the subscriber aggregation device 23 notifies the communication control device 10 of the collected ONU status of each user (step S311), thereby confirming that the edge router has been switched.

[0082] (3-4. Effects of Embodiment 3) In embodiment 3, the communication control device 10 detects from the subscriber aggregation device 23, which is an external server, whether or not each user terminal 20 whose accommodation is being switched from the first edge router 22a to the second edge router 22b is in a call, and the subscriber aggregation device 23 notifies user terminals other than the detected user terminals that are not in a call of an OUN restart, and controls the user terminals that are not in a call to re-acquire an IP address. This allows the communication control device 10 to switch edge routers without interrupting a call. As a result, the communication control device 10 can switch edge routers without disconnecting the call, thereby reducing the impact on users.

[0083] Furthermore, the communication control device 10 can reduce the load by having the subscriber aggregation device 23 monitor whether a packet with a specific CoS value has been output from the user terminal 20 .

[0084] <Program> A program describing the processes executed by the communication control device 10 according to the above embodiment in a computer-executable language can also be created. In one embodiment, the communication control device 10 can be implemented by installing a communication processing program that executes the above communication control process as package software or online software on a desired computer. For example, by executing the above communication processing program on an information processing device, the information processing device can function as the communication control device 10. Other examples of information processing devices include mobile communication terminals such as smartphones, mobile phones, and PHS (Personal Handyphone Systems), as well as slate terminals such as PDAs (Personal Digital Assistants). The functions of the communication control device 10 may also be implemented on a cloud server.

[0085] 11 is a diagram showing an example of a computer that executes a communication control program. The computer 1000 includes, for example, a memory 1010, a CPU 1020, a hard disk drive interface 1030, a disk drive interface 1040, a serial port interface 1050, a video adapter 1060, and a network interface 1070. These components are connected by a bus 1080.

[0086] The memory 1010 includes a ROM (Read Only Memory) 1011 and a RAM 1012. The ROM 1011 stores a boot program such as a BIOS (Basic Input Output System). The hard disk drive interface 1030 is connected to a hard disk drive 1090. The disk drive interface 1040 is connected to a disk drive 1100. A removable storage medium such as a magnetic disk or optical disk is inserted into the disk drive 1100. The serial port interface 1050 is connected to a mouse 1110 and a keyboard 1120, for example. The video adapter 1060 is connected to a display 1130, for example.

[0087] Here, the hard disk drive 1090 stores, for example, an OS 1091, an application program 1092, a program module 1093, and program data 1094. Each piece of information described in the above embodiment is stored in the hard disk drive 1090 or memory 1010, for example.

[0088] The communication control program is stored in the hard disk drive 1090 as, for example, a program module 1093 in which instructions to be executed by the computer 1000 are written. Specifically, the program module 1093 in which each process executed by the communication control device 10 described in the above embodiment is written is stored in the hard disk drive 1090.

[0089] Data used for information processing by the communication control program is stored as program data 1094, for example, in the hard disk drive 1090. Then, the CPU 1020 reads the program module 1093 and the program data 1094 stored in the hard disk drive 1090 into the RAM 1012 as necessary, and executes each of the above-described procedures.

[0090] The program module 1093 and program data 1094 related to the communication control program are not limited to being stored in the hard disk drive 1090, but may be stored in a removable storage medium, for example, and read by the CPU 1020 via the disk drive 1100. Alternatively, the program module 1093 and program data 1094 related to the communication control program may be stored in another computer connected via a network such as a LAN (Local Area Network) or a WAN (Wide Area Network), and read by the CPU 1020 via the network interface 1070.

[0091] Although the present invention has been described above as an embodiment, the present invention is not limited to the description and drawings that form part of the disclosure of the present invention. In other words, other embodiments, examples, and operational techniques that can be made by those skilled in the art based on the present invention are all included in the scope of the present invention.

[0092] REFERENCE SIGNS LIST 10 Communication control device 20 User terminal 21 DHCP server 22 Edge router 11 Communication unit 12 Input unit 13 Output unit 14 Control unit 14a Detection unit 14b Reacquisition control unit 15 Storage unit 15a User information DB 15b Traffic data DB 15c Subscriber aggregation information DB

Claims

1. A communication control device characterized by having: a detection unit that detects whether each user terminal whose accommodation is being switched from a first edge router to a second edge router is in a call; and a reacquisition control unit that blocks telephone routes for user terminals that are not in a call other than the user terminals that are in a call detected by the detection unit, and controls the user terminals that are not in a call to reacquire an IP address.

2. The communication control device described in claim 1, characterized in that the detection unit notifies the first edge router to enable Netflow, collects information on user terminals that are in calls using Netflow, and uses the collected information to detect whether each user terminal is in a call.

3. The communication control device according to claim 1, wherein the reacquisition control unit instructs the DHCP server to suppress force renew for the user terminal in communication detected by the detection unit.

4. A communication control method executed by a communication control device, comprising: a detection step of detecting whether a user terminal whose accommodation is being switched from a first edge router to a second edge router is currently in a call; and a re-acquisition control step of blocking the telephone route of a user terminal that is not currently in a call as a result of said detection, and controlling said user terminal to acquire an IP address.

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