Communication control device, communication system, and communication control method

Abstract

Provided is a communication control device comprising: an acquisition unit that acquires connection source identification information from a first termination unit which is included in at least a communication device of a migration source and connection source identification information from a second termination unit which is included in a communication device of a migration destination; and a control unit that, when a migration of a part of functions including the first termination unit to the communication device of the migration destination is performed, controls such that, within the communication device of the migration destination, there is no overlap between connection source identification information of a first proxy response unit which communicates with another device by converting the connection source identification information of the first termination unit and connection source identification information of a second proxy response unit which communicates with another device by converting the connection source identification information of the second termination unit.　

Description

COMMUNICATION CONTROL DEVICE, COMMUNICATION SYSTEM, AND COMMUNICATION CONTROL METHOD

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

[0002] Base stations (gNBs) that constitute a 5G (Generation) system communicate by establishing SCTP (Stream Control Transmission Protocol) sessions with 5GC (5G Core), which is a device that accommodates the base stations (see, for example, Non-Patent Document 1). In a model in which base stations are functionally separated, gNBs are functionally separated into CUs (Central Units) and DUs (Distributed Units), and the CUs and DUs are also connected by SCTP sessions.

[0003] With the advancement of virtualization technology, the virtualization of base station functions is also being considered, and flexible functional allocation according to use cases is expected. Since there are concerns that configuration changes during operation may affect the services and users currently accommodated, a method that minimizes this impact as much as possible is required. However, as described above, connections between each node and function are made via SCTP sessions. Therefore, if an SCTP session is disconnected when a configuration change is made, it takes time to reconnect, raising concerns about the impact on communication services.

[0004] Stewart, R., M. Tuxen, M. and Nielsen, K., “Stream Control Transmission Protocol”, RFC9260, DOI 10.17487 / RFC9260, June 2022, https: / / www.rfc-editor.org / info / rfc9260.

[0005] As a conventional technology, it may be possible to solve the above problem by using a technology such as NAPT (Network Address Port Translation) that converts an IP address and port number into a different IP address and port number. However, the functions defined in the standard only allow for simple conversion of IP addresses and port numbers. Therefore, it is difficult to shorten the service interruption time. In particular, when an SCTP session reconnection is involved, the connection information held in each node is also discarded when the connection is severed, which is one of the factors that lengthens the service interruption time. To shorten the service interruption time, a technology is required that enables network configuration changes while maintaining the connection information held in each node without disconnecting the SCTP session. This problem is not limited to SCTP, but occurs in TCP (Transmission Control Protocol) in general.

[0006] In view of the above circumstances, an object of the present invention is to provide a technique that can shorten the time during which service is interrupted when the configuration of a communication device is changed.

[0007] One aspect of the present invention is a communication control device that includes: an acquisition unit that acquires source identification information from at least a first termination unit provided in a source communication device and a second termination unit provided in a destination communication device; and a control unit that, when transferring some functions including the first termination unit to the destination communication device, controls the destination communication device so that the source identification information of a first proxy response unit that converts the source identification information of the first termination unit to communicate with other devices and the source identification information of a second proxy response unit that converts the source identification information of the second termination unit to communicate with other devices do not overlap.

[0008] One aspect of the present invention is a communication system comprising a source communication device, a destination communication device, and a communication control device that controls the source communication device and the destination communication device, wherein the source communication device comprises a first terminal unit having a communication function for communicating with at least other devices, and a first proxy response unit that converts the connection source identification information of the first terminal unit into connection source identification information assigned by the communication control device and communicates with other devices, the destination communication device comprises a second terminal unit having a communication function for communicating with at least other devices, and a second proxy response unit that converts the connection source identification information of the second terminal unit and communicates with other devices, and the communication control device comprises an acquisition unit that acquires the connection source identification information from each of the first terminal unit and the second terminal unit, and a control unit that controls the connection source identification information of the first proxy response unit and the connection source identification information of the second proxy response unit to not overlap within the destination communication device when some functions including the first terminal unit are transferred to the destination communication device.

[0009] One aspect of the present invention is a communication control method that acquires source identification information from at least a first terminal unit provided in a source communication device and a second terminal unit provided in a destination communication device, and when transferring some functions including the first terminal unit to the destination communication device, controls the destination communication device so that the source identification information of a first proxy response unit that converts the source identification information of the first terminal unit to communicate with other devices and the source identification information of a second proxy response unit that converts the source identification information of the second terminal unit to communicate with other devices do not overlap.

[0010] According to the present invention, it is possible to reduce the time during which services are interrupted when the configuration of a communication device is changed.

[0011] Fig. 1 is a diagram showing an example of the configuration of a communication system in an embodiment; Fig. 2 is a diagram showing an example of a management table in an embodiment; Fig. 3 is a diagram for explaining an overview when the technology of the present invention is not applied; Fig. 4 is a diagram for explaining an overview when the technology of the present invention is applied; Fig. 5 is a flowchart showing the flow of processing performed by a communication control device in an embodiment; Fig. 6 is a diagram showing an example of an updated management table in an embodiment.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] Fig. 1 is a diagram showing an example of the configuration of a communication system 100 according to an embodiment. The communication system 100 includes a plurality of servers 10 and a communication control device 20. While Fig. 1 shows a configuration in which the communication system 100 includes three servers 10-1 to 10-3, the communication system 100 may include four or more servers 10.

[0014] The servers 10 communicate with each other by establishing a session using a predetermined communication protocol. The predetermined communication protocol is a communication protocol used for communication using a port number and an IP address, such as SCTP or TCP. In the example shown in Fig. 1, the server 10-1 establishes a session using a predetermined communication protocol to communicate with the servers 10-2 and 10-3. The servers 10-1 to 10-3 are connected to the communication control device 20 via a control line.

[0015] A server 10 is a communication device that communicates with other servers 10. A different IP address is assigned to each server 10. In addition, the servers 10 virtualize some of their functions using virtualization technology. In addition, the servers 10 migrate some of the virtualized functions between the servers 10. In the following description, the server 10 that migrates some of its functions through migration is referred to as a source server, and the server 10 to which some of its functions are migrated through migration is referred to as a destination server.

[0016] The server 10 includes a virtualization unit 11, a termination unit 12, and a proxy response unit 13. The virtualization unit 11 virtualizes some functions using virtualization technology. The virtualization technology used by the virtualization unit 11 is an existing technology. For example, the virtualization unit 11 may use virtualization technology such as a container or a VM (Virtual Machine). The virtualization unit 11 virtualizes, for example, the termination unit 12 and the proxy response unit 13.

[0017] The termination unit 12 has a communication function for communicating with at least the termination unit 12 provided in another server 10. The termination unit 12 communicates with another termination unit 12 using a predetermined IP address and a predetermined port number. For example, the termination unit 12 transmits data to another termination unit 12 including connection source information and connection destination information. The connection source information is information indicating the IP address and port number (connection source identification information) used by the termination unit 12 (its own device). The connection destination information is information indicating the IP address and port number used by the destination termination unit 12.

[0018] The IP address used by the termination unit 12 is an address that is different from the IP address of each server 10 and the IP addresses used by the termination units 12 of other servers 10. In other words, the IP addresses used by the termination unit 12 are addresses that do not overlap. The port number used by the termination unit 12 is an arbitrary port number used for each server 10. Therefore, the port number used by the termination unit 12 may be a port number that overlaps with the port number used by the termination unit 12 of other servers 10. Note that the IP address and port number used by the termination unit 12 are assumed to remain unchanged before and after the migration.

[0019] 1, the termination unit 12-1 included in the server 10-1 uses port number "10001," the termination unit 12-2 included in the server 10-2 uses port number "10002," and the termination unit 12-3 included in the server 10-3 uses port number "10002." In this way, FIG. 1 shows an example in which the termination units 12-2 and 12-3 use the same port number.

[0020] The server 10 notifies the communication control device 20 of the port number of the termination unit 12. The timing for notifying the communication control device 20 of the port number may be when requested by the communication control device 20, or at other times.

[0021] The proxy response unit 13 converts the connection source information included in the transmission data transmitted from the termination unit 12 into other connection source information, and transmits the transmission data to the other termination unit 12. In the proxy response unit 13, the port number used on the termination unit 12 side is assigned by the communication control device 20. The port number used between the multiple proxy response units 13 is assigned by the communication control device 20. For example, the port number used between the multiple proxy response units 13 may be any value that does not overlap. Here, the port number used between the multiple proxy response units 13 does not need to be set. Note that the proxy response units 13 provided in different servers 10 may use overlapping port numbers.

[0022] The communication control device 20 is a device that controls each server 10. The communication control device 20 acquires port numbers from each server and manages the port numbers according to the communication path. For example, the communication control device 20 assigns port numbers to each proxy response unit 13 based on the acquired port numbers. The communication control device 20 may assign duplicate port numbers to proxy response units 13 provided in different servers 10, but assigns different port numbers to proxy response units 13 provided in the same server 10.

[0023] The communication control device 20 includes an acquisition unit 21 and a control unit 22. The acquisition unit 21 acquires a port number from each of the termination units 12 included in each server 10. The acquisition unit 21 acquires a port number from at least the termination unit 12 included in the source server and the termination unit 12 included in the destination server. When migrating some of the functions including the termination unit 12 included in the destination server to the destination server, the control unit 22 controls the destination server so that the port number of the proxy response unit 13 included in the destination server does not overlap with the port number of the proxy response unit 13 to be migrated included in the source server.

[0024] The communication control device 20 holds a management table shown in FIG. 2 and manages the settings of each proxy response unit 13 based on the management table. FIG. 2 is a diagram showing an example of a management table in an embodiment. As shown in FIG. 2, information regarding the settings of the proxy response unit 13 provided in each server 10 is registered in the management table. FIG. 2 shows a case where the proxy response unit 13-3 provided in the proxy response unit 13-3 is migrated to another server 10. Therefore, the management table shown in FIG. 2 has items related to the proxy response unit 13-3, namely, the proxy response unit 13-3 (before migration) and the proxy response unit 13-3 (after migration). Note that when another proxy response unit 13 is to be migrated, information before and after migration regarding the proxy response unit 13 to be migrated is similarly registered.

[0025] In the management table, values ​​of the termination unit side port number, the port number of the connection source proxy response unit, and the port number of the connection destination proxy response unit are registered for each proxy response unit 13. The termination unit side port number represents the port number used by the termination unit 12 to which the proxy response unit 13 is connected. For example, since the proxy response unit 13-1 is connected to the termination unit 12-1, "10001", which is the port number used by the termination unit 12-1, is registered in the termination unit side port number item corresponding to the proxy response unit 13-1. For example, since the proxy response unit 13-2 is connected to the termination unit 12-2, "10002", which is the port number used by the termination unit 12-2, is registered in the termination unit side port number item corresponding to the proxy response unit 13-2. For example, since the proxy response unit 13-3 is connected to the termination unit 12-3, "10002", which is the port number used by the termination unit 12-3, is registered in the termination unit side port number item corresponding to the proxy response unit 13-3.

[0026] The port number of the connection source proxy response unit represents the port number used by the proxy response unit 13 (own device) connected to the proxy response unit 13 provided in another server 10. For example, "20001", which is the port number assigned to the proxy response unit 13-1, is registered in the port number field of the connection source proxy response unit corresponding to proxy response unit 13-1. For example, "20002", which is the port number assigned to the proxy response unit 13-2, is registered in the port number field of the connection source proxy response unit corresponding to proxy response unit 13-2. For example, "20002", which is the port number assigned to the proxy response unit 13-3, is registered in the port number field of the connection source proxy response unit corresponding to proxy response unit 13-3.

[0027] The port number of the destination proxy response unit represents the port number used by the proxy response unit 13 provided in the other server 10 to which the proxy response unit 13 is connected. For example, proxy response unit 13-1 is connected to proxy response unit 13-3 provided in server 10-3. Therefore, "20002," the port number used by proxy response unit 13-3, is registered as the port number of the destination proxy response unit corresponding to proxy response unit 13-1. For example, proxy response unit 13-2 is connected to proxy response unit 13-1 provided in server 10-1. Therefore, "20001," the port number used by proxy response unit 13-1, is registered as the port number of the destination proxy response unit corresponding to proxy response unit 13-2. For example, proxy response unit 13-3 is connected to proxy response unit 13-1 provided in server 10-1. Therefore, "20001," the port number used by proxy response unit 13-1, is registered as the port number of the destination proxy response unit corresponding to proxy response unit 13-3.

[0028] Next, the difference between a case where the technology of the present invention is used and a case where the technology of the present invention is not used will be described with reference to Figures 3 and 4. For the sake of simplicity, the virtualization unit 11 is not shown in Figures 3 and 4.

[0029] (When the technology of the present invention is not applied) Fig. 3 is a diagram for explaining an overview of a case when the technology of the present invention is not applied. As shown in Fig. 3, when the technology of the present invention is not applied, each server 10 does not have a proxy response unit 13. In Fig. 3, it is considered that the termination unit 12-3 provided in the server 10-3 is migrated to the server 10-2. For example, when moving the termination unit 12 between servers 10, it is desirable to keep the IP address and port number inherited so as to carry out the movement without affecting communication.

[0030] As shown in FIG. 3 , the port number used by the termination unit 12-2 of the server 10-2 is "10002," and the port number used by the termination unit 12-3 of the server 10-3 is also "10002." Therefore, before the migration, there was no impact on communication because the port numbers overlapped between the different servers 10. However, after the migration, the port numbers overlap on the same server 10. As a result, the session is disconnected, posing a problem of the need to reconnect the session. In this way, when the termination units 12 communicate with each other in a manner linked to an IP address and a port number, such as SCTP, when the termination unit 12 is dynamically moved to another server, it is necessary to inherit the same information and continue communication. However, without the application of the technology of the present invention, if the same port number as that used on the migration source server is already being used on the migration destination server, it is not possible to inherit the same information and communicate.

[0031] (When the Technology of the Present Invention is Applied) FIG. 4 is a diagram for explaining an overview when the technology of the present invention is applied. In FIG. 4, it is considered that the termination unit 12-3 and the proxy response unit 13-3 provided in the server 10-3 are migrated to the server 10-2 by migration. As shown in FIG. 4, the port number used by the termination unit 12-2 provided in the server 10-2 is "10002," and the port number used by the termination unit 12-3 provided in the server 10-3 is also "10002." Therefore, before the migration, there was no impact on communication because the port numbers were duplicated on different servers 10, but after the migration, the port numbers are duplicated on the same server 10. In response to this, as shown in FIG. 4, in the present invention, a proxy response unit 13 is provided to avoid duplication of port numbers used by the termination unit 12 at the migration destination.

[0032] The communication control device 20 then assigns different port numbers to be used among the multiple proxy response units 13, thereby controlling the termination unit 12 so that there are no restrictions on the port numbers used. For example, the termination unit 12 and the proxy response unit 13 use virtualization technology such as container technology to treat the two functions as a set, so that the port numbers used by the termination unit 12 do not affect the operating server 10. Therefore, when migrating between servers 10, the network can be designed without considering duplication of port numbers used by the termination unit 12. This makes it possible to avoid duplication of port numbers within the same server 10. As a result, migration to another server can be easily performed.

[0033] 5 is a flowchart showing the flow of processing performed by the communication control device 20 in this embodiment. In the processing of FIG. 5, it is assumed that server 10-3 is the source server and server 10-2 is the destination server. Furthermore, it is assumed that the termination unit 12-1 of server 10-1 and the termination unit 12-3 of server 10-3 are communicating with each other. For simplicity of explanation, at the start of the processing of FIG. 5, the port numbers used by the termination unit 12 and proxy response unit 13 of each server 10 are assumed to be the port numbers shown in FIG. 1.

[0034] The communication control device 20 acquires connection source identification information from the source server (server 10-3) and saves the settings of the proxy response unit 13-3 included in the source server (server 10-3) in a management table (step S101). Specifically, the communication control device 20 first acquires the port number "10002" used by the proxy response unit 13-3 as connection source identification information from the source server (server 10-3). The communication control device 20 then registers the acquired port number "10002" in the item for the port number on the termination side of the proxy response unit 13-3 in the management table, thereby saving the settings of the proxy response unit 13-3 in the management table.

[0035] Next, the communication control device 20 acquires an unused port number in the destination server (server 10-2) by acquiring connection source identification information from the destination server (server 10-2) (step S102). Specifically, the communication control device 20 first acquires port number "10002" used by the proxy response unit 13-2 as connection source identification information from the destination server (server 10-2). Then, the communication control device 20 acquires port numbers excluding port number "10002".

[0036] The communication control device 20 determines whether the acquired unused port number overlaps with the original port number of the proxy response unit 13-3 of the source server (server 10-3) (step S103). If the communication control device 20 determines that the acquired unused port number overlaps with the original port number of the proxy response unit 13-3 of the source server (server 10-3) (step S103—YES), the communication control device 20 assigns a new port number to the proxy response unit 13-3 of the source server (server 10-3) (step S104). Here, the new port number is a port number different from the unused port number acquired in the processing of step S102. For example, the communication control device 20 assigns "20003" as the new port number to the proxy response unit 13-3.

[0037] As a result, the communication control device 20 determines the setting information for the proxy response unit 13-3 at the migration destination (step S105). That is, when the termination unit 12-3 and the proxy response unit 13-3 provided in the migration source server (server 10-3) are migrated to the migration destination server (server 10-2), the communication control device 20 determines the information on the port number to be set in the proxy response unit 13-3. For example, the communication control device 20 sets port number "20003" for the proxy response unit 13-3 as the port number to be used between the multiple proxy response units 13, and stores setting information for setting port number "10002" for the proxy response unit 13-3 as the port number to be used on the termination unit 12-3 side in the management table. In this case, the communication control device 20 registers the information for port number "20003" in the port number item of the proxy response unit from which the proxy response unit 13-3 (after movement) connects in the management table, and registers the information for port number "10002" in the port number item on the termination side of the proxy response unit 13-3 (after movement) in the management table.

[0038] The communication control device 20 saves the states of the termination unit 12-1 of the destination server 10-1 and the termination unit 12-3 of the source server 10-3, and temporarily suspends the termination units 12-1 and 12-3 (step S106). As a result, communication is temporarily suspended between the termination unit 12-1 of the communicating server 10-1 and the termination unit 12-3 of the communicating server 10-3.

[0039] The communication control device 20 rewrites the information on the port number of the destination proxy response unit in the proxy response unit 13-1 provided in the server 10-1 connected to the proxy response unit 13-3 provided in the server 10-3 that is the connection source (step S107). Specifically, the communication control device 20 rewrites the value of port number "20002" registered in the item of the port number of the destination proxy response unit of the proxy response unit 13-1 provided in the server 10-1 in the management table to the port number "20003" assigned in the processing of step S104. As a result, the information on the proxy response unit 13-1 provided in the server 10-1 connected to the termination unit 12-3 of the migration source server is updated in the management table.

[0040] Thereafter, the communication control device 20 migrates the termination unit 12-3 and proxy response unit 13-3, which are the connection source, to the destination server. Specifically, the communication control device 20 migrates the termination unit 12-3 and proxy response unit 13-3 provided in the source server as a set to the destination server. In response to an instruction from the communication control device 20, the source server migrates the termination unit 12-3 and proxy response unit 13-3 to the destination server.

[0041] After the migration to the destination server is complete, the communication control device 20 reflects the new settings in the proxy response unit 13-3 of the server 10-3 as necessary (step S108). For example, the communication control device 20 sets the port number "20003" assigned in the processing of step S104 to the proxy response unit 13-3. As a result, in the destination server, the port numbers used are different, such as the port number "20002" used by the proxy response unit 13-2 and the port number "20003" used by the proxy response unit 13-3, so communication is not affected.

[0042] Thereafter, the communication control device 20 resumes communication by canceling the temporary suspension of the termination unit 12-1 of the destination server 10-1 and the termination unit 12-3 of the source server 10-2 (step S109). As a result, communication is resumed between the termination unit 12-1 of the server 10-1 and the termination unit 12-3 of the server 10-2.

[0043] In the process of step S103, if the communication control device 20 determines that the acquired unused port number does not overlap with the original port number of the proxy response unit 13-3 provided in the source server (server 10-3) (step S103-NO), the communication control device 20 determines the setting information of the proxy response unit 13 at the destination (step S110). That is, when the termination unit 12-3 and the proxy response unit 13-3 provided in the source server (server 10-3) are migrated to the destination server (server 10-2), the communication control device 20 determines the information of the port number to be set in the proxy response unit 13-3.

[0044] The communication control device 20 saves the states of the termination unit 12-1 of the destination server 10-1 and the termination unit 12-3 of the source server 10-3, and temporarily suspends the termination units 12-1 and 12-3 (step S111). This temporarily halts communication between the termination unit 12-1 of the communicating server 10-1 and the termination unit 12-3 of the communicating server 10-3. Then, the processing from step S108 onwards is executed.

[0045] If the communication control device 20 determines in the processing of step S103 that the acquired unused port number overlaps with the original port number of the proxy response unit 13-3 provided in the source server (server 10-3), the management table held by the communication control device 20 will look, for example, as shown in FIG. 6. FIG. 6 is a diagram showing an example of the management table after updating in the embodiment. As shown in FIG. 6, the value registered in the item for the port number of the proxy response unit connected to the proxy response unit 13-1 provided in server 10-1 is updated from "20002" to "20003." This is because, as described above, if the proxy response unit 13-3 connected to the proxy response unit 13-1 provided in server 10-1 is migrated to server 10-2, the port number will overlap with the port number used in server 10-2.

[0046] When the port number used by the proxy response unit 13 of the connection destination is changed, the port number used by the proxy response unit 13 of the connection source may also be changed. In the example described above, the proxy response unit 13 of the connection destination is the proxy response unit 13-3, and the proxy response unit 13 of the connection source is the proxy response unit 13-1. In this case, when the communication control device 20 changes the port number of the proxy response unit 13-3, it may also change the port number of the proxy response unit 13-1 to which the proxy response unit 13-3 is connected. When the communication control device 20 changes the port number of the proxy response unit 13-1, it updates the port number registered in the port number field of the proxy response unit of the connection destination in the management table.

[0047] According to the communication system 100 configured as described above, the communication control device 20 comprises an acquisition unit 21 that acquires port numbers from at least the termination unit 12 provided in the source server and the termination unit 12 provided in the destination server, and a control unit 22 that, when migrating some functions including the termination unit 12 to the destination server, controls the destination server so that the port number of the proxy response unit 13 provided in the destination server does not overlap with the port number of the proxy response unit 13 to be migrated provided in the source server.

[0048] In this way, the communication control device 20 changes the setting information (e.g., port number) of the proxy response unit 13 based on the information of the termination unit 12. This control makes it possible to change the configuration of the server 10 while retaining the session settings and state of the termination unit 12. Furthermore, although there is a temporary communication outage to change the configuration of the server 10, there is no need to re-establish the session because the session settings and state of the termination unit 12 remain retained. The duration of the temporary communication outage is shorter than the duration of re-establishing the session. This makes it possible to shorten the duration of service interruption when changing the configuration of the communication device.

[0049] In a mobile system, a base station and a core network are connected via an SCTP session. In this case, it is expected that a flexible network can be realized by dynamically migrating virtualized base station functions. In this case, if the SCTP session is disconnected, it takes time to reconnect. However, the present invention can switch without disconnecting the SCTP session, thereby shortening the time during which services are interrupted.

[0050] Furthermore, in the communication system 100, it is possible to change the configuration while inheriting the settings and state of the SCTP session of the termination unit 12 (e.g., corresponding to the function of a base station) by changing the settings using the proxy response unit 13. As a result, it is possible to realize flexible changes in the network configuration.

[0051] Some or all of the functional units of the server 10 are realized as software by a processor such as a CPU (Central Processing Unit) executing a program stored in a storage device having a non-volatile storage medium (non-transitory storage medium) and in the storage unit. The program may be recorded on a computer-readable non-transitory storage medium. Examples of computer-readable non-transitory storage media include portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), and CD-ROMs (Compact Disc Read Only Memory), and storage devices such as hard disks built into computer systems.

[0052] Some or all of the functional units of the server 10 may be realized using hardware including electronic circuits (electronic circuits or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0053] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0054] The present invention can be applied to a technology for migrating virtualized functions.

[0055] REFERENCE SIGNS LIST 10... server, 11, 11-1 to 11-3... virtualization unit, 12, 12-1 to 12-3... termination unit, 13, 13-1 to 13-3... proxy response unit, 20... communication control device, 21... acquisition unit, 22... control unit

Claims

1. A communication control device comprising: an acquisition unit that acquires source identification information from at least a first termination unit provided in a source communication device and a second termination unit provided in a destination communication device; and a control unit that, when transferring some functions including the first termination unit to the destination communication device, controls the destination communication device so that the source identification information of a first proxy response unit that converts the source identification information of the first termination unit to communicate with other devices and the source identification information of a second proxy response unit that converts the source identification information of the second termination unit to communicate with other devices do not overlap.

2. The communication control device described in claim 1, wherein the connection source identification information is a port number, and when transferring some functions including the first termination unit to the destination communication device, the control unit acquires an unused port number in the destination communication device, and if the acquired unused port number overlaps with the port number of the first proxy response unit, assigns a new, non-overlapping port number to the first proxy response unit.

3. The communication control device according to claim 1 or 2, wherein the control unit temporarily suspends communication with other communication devices communicating with the first terminal unit until some of the functions including the first terminal unit are transferred to the destination communication device, and after the transfer of some of the functions including the first terminal unit to the destination communication device is completed, the suspension is lifted and communication is resumed.

4. A communications system comprising a source communications device, a destination communications device, and a communications control device that controls the source communications device and the destination communications device, wherein the source communications device comprises: a first termination unit having a communications function for communicating with at least other devices; and a first proxy response unit that converts the connection source identification information of the first termination unit into connection source identification information assigned by the communications control device and communicates with the other devices; the destination communications device comprises: a second termination unit having a communications function for communicating with at least other devices; and a second proxy response unit that converts the connection source identification information of the second termination unit and communicates with the other devices; and the communications control device comprises: an acquisition unit that acquires the connection source identification information from the first termination unit and the second termination unit; and a control unit that, when transferring some functions including the first termination unit to the destination communications device, controls the connection source identification information of the first proxy response unit and the connection source identification information of the second proxy response unit to not overlap within the destination communications device.

5. A communication control method comprising: acquiring source identification information from at least a first termination unit provided in a source communication device and a second termination unit provided in a destination communication device; and, when transferring some functions including the first termination unit to the destination communication device, controlling the destination communication device so that the source identification information of a first proxy response unit that converts the source identification information of the first termination unit to communicate with other devices does not overlap with the source identification information of a second proxy response unit that converts the source identification information of the second termination unit to communicate with other devices.

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