Relay system and relay method

Abstract

A relay system 2 comprises: a conversion unit 122 that deletes the data of an item specified in advance from packet data PD received from a transmission terminal ET and converts the packet data PD into converted packet data PDE; a determination unit 222 that uses the characteristics of the converted packet data PDE as a basis to determine a path for transmitting the packet data PD from among a plurality of paths for transmitting the packet data PD to a reception terminal ER; and a transmission / reception unit 121 that receives the packet data PD from the transmission terminal ET and transmits the received packet data PD to the determined path.

Description

Relay system and relay method

[0001] The present disclosure relates to a relay system and a relay method.

[0002] When communicating with a specific destination over the Internet or the like, if multiple routes with different characteristics are available, there is a need to use an appropriate route depending on the content of the communication, regardless of the destination.

[0003] SDN (Software Defined Network) is a technology for flexibly controlling communications regardless of the communication destination. OpenFlow, one implementation of SDN, transfers packets received by communication devices to a controller, which then sets the packet's treatment determined by the controller in a flow table (see Non-Patent Document 1). The flow table defines the combination of header information and the corresponding processing. Communication devices refer to the flow table to process packets.

[0004] Nick McKeown, Tom Anderson, Hari Balakrishnan, Guru Parulkar, Larry Peterson, Jennifer Rexford, Scott Shenker, and Jonathan Turner. 2008. OpenFlow: enabling innovation in campus networks. SIGCOMM Comput. Commun. Rev. 38, 2 (April 2008), 69-74.

[0005] In Non-Patent Document 1, a packet transferred from a communication device to a controller includes a destination IP address and communication content. On the other hand, an end user may wish to conceal specific content from the viewpoint of security or privacy protection.

[0006] The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a technology that can achieve both security or privacy protection and route allocation.

[0007] A relay system according to one aspect of the present disclosure includes a conversion unit that deletes data of pre-specified items from packet data received from a transmitting terminal and converts the packet data into converted packet data, a determination unit that determines, from among multiple routes for transmitting the packet data to a receiving terminal, the route along which the converted packet data should be transmitted based on characteristics of the converted packet data, and a transceiver unit that receives the packet data from the transmitting terminal and transmits the received packet data along the determined route.

[0008] A relay method of one aspect of the present disclosure includes a computer receiving packet data from a transmitting terminal, deleting pre-specified items of data from the packet data received from the transmitting terminal and converting the packet data into converted packet data, determining a route for transmitting the packet data from among multiple routes for transmitting the packet data to a receiving terminal based on characteristics of the converted packet data, and transmitting the received packet data via the determined route.

[0009] According to the present disclosure, it is possible to provide a technology that can achieve both security or privacy protection and route allocation.

[0010] FIG. 1 is a diagram illustrating the system configuration of a relay system according to the present disclosure. FIG. 2 is a diagram illustrating functional blocks of a relay device. FIG. 3 is a diagram illustrating an example of the data structure and data of a buffer of a relay device. FIG. 4 is a diagram illustrating an example of the data structure and data of item data of the relay device. FIG. 5 is a diagram illustrating an example of a packet from which a conversion unit of the relay device deletes source and destination IP addresses and MAC addresses. FIG. 6 is a diagram illustrating an example of a packet from which a conversion unit of the relay device deletes encrypted data. FIG. 7 is a diagram illustrating functional blocks of a determination device. FIG. 8 is a diagram illustrating an example of the data structure and data of accumulated data of the determination device. FIG. 9 is a diagram illustrating an example of the data structure and data of condition data of the determination device. FIG. 10 is a sequence diagram illustrating processing in a relay system according to the present disclosure. FIG. 11 is a flowchart illustrating determination processing in the determination device. FIG. 12 is a sequence diagram illustrating processing in a relay system according to a first modified example. FIG. 13 is a diagram illustrating the system configuration of a relay system according to a second modified example. FIG. 14 is a sequence diagram illustrating processing in a relay system according to the second modified example. FIG. 15 is a diagram illustrating the hardware configuration of a computer used in the relay device and the determination device.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[0012] (Relay System) A communication system 1 according to the present disclosure realizes communication between a transmitting terminal ET and a receiving terminal ER. The communication system 1 includes a first relay system 2a on the transmitting terminal ET side and a second relay system 2b on the receiving terminal ER side. The first relay system 2a and the second relay system 2b are, for example, edge routers in a communication network provided by a telecommunications carrier.

[0013] The first relay system 2a and the second relay system 2b are connected to each other via a first route R1 and a second route R2 so that they can communicate bidirectionally. The first route R1 connects the first relay system 2a and the second relay system 2b via a first telecommunications carrier network N1. The second route R2 connects the first relay system 2a and the second relay system 2b via a second telecommunications carrier network N2.

[0014] The first route R1 and the second route R2 are routes that have different user costs in terms of communication usage, such as time, quality, or cost. The first route R1 and the second route R2 are routes that differ, for example, in communication method or fee structure. Each route has its own characteristics, such as an inexpensive, low-quality route with a flat rate, an expensive, high-quality route with a pay-per-use rate, or a dedicated line route available for a flat rate. The relay system 2 according to the present disclosure enables packet data to be sent to an appropriate route depending on its communication content.

[0015] The first relay system 2a transmits a packet transmitted from a transmitting terminal ET via either a first route R1 or a second route R2. The first relay system 2a transmits a packet received from either the first route R1 or the second route R2 to the transmitting terminal ET. The first relay system 2a includes a relay device 100a and a determination device 200a.

[0016] Relay device 100a deletes data of pre-specified items from packet data received from transmitting terminal ET and converts the packet data into converted packet data. Relay device 100a transmits the converted packet data to determination device 200a. Determination device 200a references the converted packet data and determines which of first route R1 and second route R2 to use to transmit the packet data. Determination device 200a transmits an identifier of the determined route to relay device 100a. Relay device 100a transmits the packet data via the route notified by determination device 200a.

[0017] The second relay system 2b transmits a packet transmitted from the receiving terminal ER via either the first route R1 or the second route R2. The second relay system 2b transmits a packet received via either the first route R1 or the second route R2 to the receiving terminal ER. The second relay system 2b includes a relay device 100b and a determination device 200b. The second relay system 2b operates in the same manner as the first relay system 2a.

[0018] In the present disclosure, when there is no particular distinction between the first relay system 2a and the second relay system 2b, they may be simply referred to as relay system 2. Similarly, when there is no particular distinction between the relay devices 100a and 100b, they may be referred to as relay device 100. When there is no particular distinction between the determination devices 200a and 200b, they may be referred to as determination device 200. The relay system 2 may be formed by two computers, the relay device 100 and the determination device 200, or may be formed by one or three or more computers that realize the functions of these devices.

[0019] 2, the relay device 100 of the relay system 2 will be described. The relay device 100 includes data in a buffer 111 and item data 112, and functions of a transmitter / receiver 121 and a converter 122. Each piece of data is stored in a storage device such as a memory 902 or a storage 903. Each function is implemented in a CPU 901.

[0020] As shown in FIG. 3, the buffer 111 associates the identifier of the packet data received by the relay device 100 with the packet data and the identifier of the path through which the packet data was transmitted.

[0021] The item data 112 specifies the items to be deleted and converted by the conversion unit 122. As shown in Fig. 4, the item data 112 associates the items to be deleted or converted with the values ​​after deletion or conversion. The item data 112 shown in Fig. 4 indicates that encrypted items are to be deleted and that the destination IP address and destination MAC address are to be converted with dummy data or the like.

[0022] Items designated in advance by a user or an administrator of the system as items to be deleted or converted are set in the item data 112. Items to be deleted or converted are, for example, items designated by a user who wishes to keep them secret from the viewpoint of security, privacy, or confidentiality of communications, or items designated by an administrator of the relay system 2 who presumes that they should be kept secret.

[0023] In the present disclosure, packet data deletion and conversion have in common the fact that data in a specified item of packet data is deleted. In packet data deletion, data in a specified item of packet data is deleted and truncated. In packet data deletion, data indicating deletion, such as a null value, 0, or blank, is set in the deleted item. In packet data conversion, data in a specified item of packet data is converted to dummy data or the like.

[0024] The items set in item data 112 in packet data transmitted by transmitting terminal ET are deleted or converted and transmitted to determination device 200. The items set by the user or administrator are not leaked outside relay device 100. Furthermore, even if determination device 200 is operated by an external business operator, security, privacy, confidentiality of communications, and the like are guaranteed.

[0025] The transmitting / receiving unit 121 receives packet data PD from the transmitting terminal ET and transmits the received packet data PD to the route determined by the determination device 200. The transmitting / receiving unit 121 stores the packet data PD received from the transmitting terminal ET in the buffer 111. The transmitting / receiving unit 121 transmits the packet data received from the receiving terminal ER to the transmitting terminal ET.

[0026] The conversion unit 122 converts the packet data PD received from the transmitting terminal ET into converted packet data PDE by deleting data of items previously specified in the item data 112. The conversion unit 122 inputs the converted packet data PDE to the determination device 200 and receives from the determination device 200 a route identifier RID that specifies the route to the destination.

[0027] The conversion unit 122 deletes data of an item specified in the item data 112 from the packet data PD, sets a null value or the like for that item, or converts the data of the specified item to dummy data. Here, the dummy data is data from which the determination device 200 cannot identify the original data before conversion.

[0028] 5 shows an example in which the conversion unit 122 deletes the IP addresses and MAC (Media Access Control) addresses of the source and destination, respectively. FIG. 5(a) shows packet data before conversion. Predetermined values ​​are set for the IP addresses and MAC addresses of the source and destination, respectively. FIG. 5(b) shows packet data after conversion. The data "0.0.0.0" indicating deletion is set for the IP addresses of the source and destination, respectively. The data "00:00:00:00:00:00" indicating deletion is set for the MAC addresses of the source and destination, respectively. The determination device 200 cannot refer to the IP addresses and MAC addresses of the source and destination in the packet data before conversion.

[0029] 6A and 6B show an example in which the conversion unit 122 deletes data of an encrypted item. FIG. 6A shows packet data before conversion. In the packet data before conversion, encrypted data is set in the payload of the data related to IPv4. FIG. 6B shows packet data after conversion. In the packet data before conversion, data "00 00 00..." indicating deletion is set in the payload of the data related to IPv4. The determination device 200 cannot refer to the encrypted payload in the packet data before conversion.

[0030] 7, the determination device 200 of the relay system 2 will be described. The determination device 200 includes data such as a feature 211, accumulated data 212, and condition data 213, as well as functions of an analysis unit 221 and a determination unit 222. Each piece of data is stored in a storage device such as a memory 902 or a storage 903. Each function is implemented in a CPU 901.

[0031] The feature 211 is data of a value that specifies the feature of the converted packet data PDE analyzed by the analysis unit 221. The feature 211 is the packet size, the destination IP address or MAC address, or the like.

[0032] The feature 211 may be a feature common to packet data received in the past. For example, when the determination unit 222 (described later) determines a route based on the number or percentage of packets of a predetermined size among packet data received within a predetermined time period in the past, the feature 211 includes whether the reception time is within the predetermined time period in the past and whether the converted packet data in the past was a packet of the predetermined size.

[0033] The stored data 212 associates each converted packet data PDE received from the relay device 100 with the characteristics of each converted packet data PDE. For example, as shown in Fig. 8, the stored data 212 associates an identifier of the converted packet data PDE with the characteristics of the converted packet data PDE. The stored data 212 includes at least the converted packet data PDE for the period specified by the condition data 213.

[0034] The condition data 213 is data specifying a condition for the determination unit 222 to determine the destination route of the packet data PD before conversion of the converted packet data PDE.

[0035] 9, the condition data 213 associates a condition identifier, data specifying the condition, and an identifier of a path for transmitting packet data PD before conversion of converted packet data PDE that satisfies the condition. The condition data 213 shown in FIG. 9 is an example and is not limited to this.

[0036] The record with ID=1 in FIG. 9 indicates that if "10 or more packets of less than 100 bytes are detected in the past 10 seconds," packet data is sent to the "first route." Generally, packets with short packet lengths are used in voice communications. In voice communications, packet delays or loss can adversely affect communications. This condition indicates a state in which voice communication packets are sent frequently in a short period of time. This record indicates that voice communication packets are sent to the high-quality first route.

[0037] ID=2 indicates that if "10 or more packets of 1,300 bytes or more are detected in the past 30 seconds," packet data will be sent to the "second route." When sending a file with a large data size, packets with a long packet length are generally used. This condition indicates a state in which multiple large data items are sent intermittently. This record means that packets for sending a file with a large data size will be sent to the second route, which has low quality.

[0038] ID=3 indicates that packet data is sent via a "third route" if "the proportion of communications to the same destination IP address exceeds 50% in the past 10 minutes." When a sending terminal ET uses a VPN (Virtual Private Network), packets from multiple sending terminals ET using the same VPN are destined for the same IP address if they connect to the same VPN server. An increase in packets from multiple sending terminals ET using a single VPN makes it appear as if communications to the same IP address have increased relatively. This condition indicates a concentration of data sent to a single VPN. Because data is encrypted in a VPN, data sent and received via a VPN is expected to have a low risk of information leakage even if it is intercepted. This record indicates that packets sent to a single VPN are sent via a third route that passes through a cheap public network that may be subject to interception.

[0039] The analysis unit 221 analyzes the converted packet data PDE received from the relay device 100 and identifies the feature 211. The analysis unit 221 assigns an identifier to the converted packet data PDE received from the relay device 100, associates the identifier, the converted packet data PDE, and the feature 211, and stores them in the accumulated data 212.

[0040] The determination unit 222 determines a route for transmitting the packet data PD from among a plurality of routes for transmitting the packet data PD to the receiving terminal ER, based on the characteristics 211 of the converted packet data PDE. The determination unit 222 identifies a condition that matches the newly received converted packet data PDE from among the conditions defined by the condition data 213. The determination unit 222 returns a route identifier RID associated with the identified condition to the relay device 100.

[0041] The determination unit 222 also references past converted packet data PDE stored in the accumulated data 212 to identify the conditions that the newly received converted packet data PDE satisfies. For example, for the condition ID=1 in FIG. 9 , the determination unit 222 counts the number of packets of less than 100 bytes received in the past 10 seconds from the accumulated data 212. If the number of packets of less than 100 bytes received in the past 10 seconds is 10 or more, the determination unit 222 determines that the destination of the newly received converted packet data PDE is the first route. The determination unit 222 transmits the identifier of the first route to the relay device 100 as a route identifier RID.

[0042] Here, the determination unit 222 may determine whether the condition is met by using a reception time identified from timestamp information added to the converted packet data PDE registered in the accumulated data 212. Alternatively, the determination unit 222 may receive the reception time of the converted packet data PDE from the relay device 100 and determine whether the condition is met by using the received reception time.

[0043] (Relay Method) A relay method in the relay system 2 according to the present disclosure will be described with reference to FIG.

[0044] In step S11, the transmitter / receiver 121 of the relay device 100 receives packet data from the transmitting terminal ET. In step S12, the transmitter / receiver 121 copies the packet data received in step S11 to the buffer 111. In step S13, the transmitter / receiver 121 inputs the copy of the packet data received in step S11 to the converter 122.

[0045] In step S14, the conversion unit 122 converts the packet data received in step S13 by referring to the item data 112, and generates converted packet data PDE. In step S15, the conversion unit 122 inputs the converted packet data PDE to the determination device 200.

[0046] In step S16, the determination device 200 determines the route of the destination by referring to the converted packet data PDE input in step S15 and the condition data 213. In step S17, the determination device 200 returns the route identifier RID of the destination to the conversion unit 122 of the relay device 100.

[0047] In step S18, the converter 122 stores the route identifier RID received in step S17 in the buffer 111. At this time, the converter 122 associates the packet data received in step S13 with the route identifier RID in the buffer 111.

[0048] In step S19, the conversion unit 122 acquires the packet data and the route identifier RID from the buffer 111. In step S20, the conversion unit 122 deletes the packet data and the route identifier RID acquired in step S19 from the buffer 111. In step S21, the conversion unit 122 inputs the packet data and the route identifier RID to the transmission / reception unit 121.

[0049] In step S22, the transmitting / receiving unit 121 transmits the packet data to the route specified by the route identifier RID.

[0050] The determination process in the determination device 200 according to the present disclosure will be described with reference to Fig. 11. This process corresponds to the process of step S16 in Fig. 10.

[0051] In step S31, the determination device 200 receives the converted packet data PDE from the relay device 100. This process corresponds to step S15 in FIG.

[0052] In step S32, the determination device 200 extracts the converted packet data PDE's characteristics 211. In step S33, the determination device 200 stores the converted packet data PDE and its characteristics 211 in the accumulated data 212.

[0053] In step S34, the determination device 200 determines the route of the packet data PD before conversion of the converted packet data PDE by referring to the condition data 213 and the stored data 212. In step S35, the determination device 200 transmits the route identifier RID of the determined route to the relay device 100.

[0054] (First Modification) A relay system 2 according to a first modification will be described with reference to Fig. 12. A relay device 100 according to the first modification transmits the second and subsequent packet data of a series of packet data via the same route as the first packet data, without requesting route determination from the determination device 200.

[0055] Specifically, the transmitting / receiving unit 121 identifies the destination route of the newly received packet data PD by referring to the buffer 111 in which packet data is associated with an identifier of the destination route of the packet data. If the new packet data received from the transmitting terminal ET and the packet data stored in the buffer 111 are a series of packets, the transmitting / receiving unit 121 transmits the new packet data to the destination route of the packet data.

[0056] For example, when the transmitting / receiving unit 121 receives a first packet data, it stores the first packet data in the buffer 111. The transmitting / receiving unit 121 refers to the buffer 111 and determines whether or not there is a preceding series of packet data.

[0057] In the present disclosure, a series of packet data refers to, for example, packet data that is the same for the transmitting terminal ET and the receiving terminal ER. Specifically, the transmitting / receiving unit 121 determines whether packet data with the same source IP address and destination IP address as the first packet data is stored in the buffer 111. Here, if a VLAN is used between the transmitting terminal ET and the first relay system 2a, the transmitting / receiving unit 121 of the first relay system 2a may further use the ID of the VLAN on the transmitting terminal ET side to determine whether the packet data is a series of packet data. Similarly, if a VLAN is used between the receiving terminal ER and the second relay system 2b, the transmitting / receiving unit 121 of the second relay system 2b may further use the ID of the VLAN on the receiving terminal ER side to determine whether the packet data is a series of packet data. Furthermore, the transmitting / receiving unit 121 may determine whether the packet data is a series of packet data using data of other items identified from the packet data. The method of determining whether the packet data is a series of packet data described here is merely an example, and other methods may be used to identify the packet data.

[0058] If there is no preceding series of packet data in the buffer 111, the conversion unit 122 converts the first packet data and inputs the converted packet data PDE to the determination device 200. The conversion unit 122 receives the route identifier RID from the determination device 200, and updates the buffer 111 by associating the received route identifier RID with the first packet data.

[0059] Upon receiving the second packet data, the transmitter / receiver 121 stores the second packet data in the buffer 111. The transmitter / receiver 121 references the buffer 111 to determine whether or not there is a preceding series of packet data. If the first packet data and the second packet data are a series of packet data, the transmitter / receiver 121 obtains the route identifier RID of the first packet data from the buffer 111. The transmitter / receiver 121 transmits the second packet data PD along the route specified by the route identifier RID.

[0060] A relay method in the relay system 2 according to the first modification will be described with reference to Fig. 12. Although omitted in Fig. 12, it is assumed that the processes from S11 to S15 in Fig. 10 have already been performed on the first packet data.

[0061] In step S51, the determination device 200 determines the route of the destination by referring to the converted packet data PDE converted from the first packet data and the condition data 213. In step S52, the determination device 200 returns the route identifier RID of the destination to the conversion unit 122 of the relay device 100.

[0062] In step S53, the converter 122 stores the route identifier RID received in step S52 in the buffer 111. At this time, the converter 122 associates the first packet data with the route identifier RID in the buffer 111.

[0063] In step S54, the conversion unit 122 acquires the packet data and the route identifier RID from the buffer 111. In step S55, the conversion unit 122 inputs the packet data and the route identifier RID to the transmission / reception unit 121. Note that in the process shown in Fig. 10, the conversion unit 122 deletes the packet data and the route identifier RID acquired in step S54 from the buffer 111, but in the first modified example, no deletion process is performed.

[0064] In step S56, the transmitting / receiving unit 121 transmits the first packet data to the route specified by the route identifier RID.

[0065] Thereafter, in step S61, the transmitter / receiver 121 of the relay device 100 receives second packet data related to the first packet data from the transmitting terminal ET.

[0066] In step S62, the transmitting / receiving unit 121 copies the second packet data received in step S61 to the buffer 111. In step S63, the transmitting / receiving unit 121 acquires the route identifier RID of the first packet data PD that is a series with the second packet data PD from the buffer 111. In step S64, the transmitting / receiving unit 121 associates the second packet data PD with the route identifier acquired in step S63 and stores them in the buffer 111.

[0067] In step S65, the transmitting / receiving unit 121 transmits the second packet data to the route specified by the route identifier RID.

[0068] In the first modification, the relay device 100 queries the determination device 200 about the route for the first packet data among a series of multiple packet data, and stores the result in the buffer 111. The relay device 100 does not query the determination device 200 about the route for the second and subsequent packet data. The relay device 100 obtains the route identifier of the preceding packet data that forms the series from the buffer 111, and transmits the packet data along the obtained route. The relay system 2 according to the first modification can reduce the amount of communication between the relay device 100 and the determination device 200, and avoid communication delays.

[0069] (Second Modification) A communication system 1a according to a second modification will be described with reference to Fig. 13. The communication system 1a shown in Fig. 13 is similar to the communication system 1 shown in Fig. 1 in that it includes a first relay system 2a on the transmitting terminal ET side, but differs in that it includes a simple relay device 900 on the receiving terminal ER side, rather than a second relay system 2b.

[0070] The relay device 900 according to the second modification transmits packet data to the receiving terminal ER or the transmitting terminal ET depending on the destination of the packet data. Unlike the relay system 2, the relay device 900 does not have a function of selecting one of multiple routes based on the characteristics of the packet data.

[0071] Therefore, the conversion unit 122 of the relay device 100a of the first relay system 2a converts the address of the sender of the packet data received from the sending terminal ET into the address of the relay device 100 corresponding to the route along which the packet data is sent. This allows the first relay system 2a to receive return packet data from the receiving terminal ER via the same route as the route along which the packet data addressed to the receiving terminal ER was sent.

[0072] The conversion unit 122 converts the address of the sender of the packet data into the address of the relay device 100 corresponding to the route along which the packet data is transmitted, for example, by using a network address translation (NAT) function. In the present disclosure, a case will be described in which the conversion unit 122 converts the sender address, but the transmission / reception unit 121 may also convert the address.

[0073] The processing of the first relay system 2a according to the second modified example will be described with reference to FIG.

[0074] The processes of steps S11 to S19 in Fig. 14 are the same as the processes according to the present disclosure that have been described with reference to Fig. 10. In step S19, the conversion unit 122 acquires packet data and a route identifier from the buffer 111, and then in step S80 converts the source address of the packet data acquired from the buffer 111 into the address of the first relay system 2a for connecting to the route corresponding to the route identifier RID.

[0075] The processing of steps S20 to S22 is the same as the processing according to the present disclosure described with reference to Fig. 10. The source address of the packet data transmitted in step S22 is the address of the first relay system 2a corresponding to the destination route.

[0076] The relay system 2 according to the present disclosure determines a route to a destination of the packet data PD based on converted packet data PDE obtained by converting data of predetermined items of the packet data PD received from the transmitting terminal ET. The relay system 2 can achieve both security or privacy protection and route allocation.

[0077] The relay device 100 and the determination device 200 according to the present disclosure described above each use a general-purpose computer system including, for example, a CPU (Central Processing Unit, processor) 901, a memory 902, a storage 903 (HDD: Hard Disk Drive, SSD: Solid State Drive), a communication device 904, an input device 905, and an output device 906. In this computer system, the CPU 901 executes a program loaded on the memory 902, thereby realizing the respective functions of the relay device 100 and the determination device 200.

[0078] The relay device 100 and the determination device 200 may each be implemented by a single computer or by multiple computers. Furthermore, the relay device 100 and the determination device 200 may each be a virtual machine implemented on a computer.

[0079] The programs of the relay device 100 and the determination device 200 can be stored in a computer-readable recording medium such as an HDD, an SSD, a Universal Serial Bus (USB) memory, a Compact Disc (CD), or a Digital Versatile Disc (DVD), or can be distributed via a network. The computer-readable recording medium is, for example, a non-transitory recording medium.

[0080] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure.

[0081] REFERENCE SIGNS LIST 1 Communication system 2 Relay system 100, 900 Relay device 111 Buffer 112 Item data 121 Transmitting / receiving unit 122 Conversion unit 200 Determination device 211 Features 212 Stored data 213 Condition data 221 Analysis unit 222 Determination unit 901 CPU 902 Memory 903 Storage 904 Communication device 905 Input device 906 Output device ER Receiving terminal ET Transmitting terminal PD Packet data PDE Converted packet data RID Route identifier

Claims

1. A relay system comprising: a conversion unit that deletes pre-specified data items from packet data received from a transmitting terminal and converts the packet data into converted packet data; a determination unit that determines, from among multiple routes for transmitting the packet data to a receiving terminal, the route along which the converted packet data should be transmitted, based on the characteristics of the converted packet data; and a transmission / reception unit that receives the packet data from the transmitting terminal and transmits the received packet data along the determined route.

2. The relay system according to claim 1, wherein the characteristics include common characteristics with the packet data received in the past.

3. The relay system of claim 1, wherein the transmitter / receiver refers to a buffer in which the packet data and an identifier of the route to which the packet data is to be sent are associated, and if new packet data received from the sending terminal and the packet data stored in the buffer are a series of packets, the transmitter / receiver sends the new packet data to the route to which the packet data is to be sent.

4. A relay method in which a computer receives packet data from a transmitting terminal, deletes pre-specified items of data from the packet data received from the transmitting terminal, and converts the packet data into converted packet data, determines a route for transmitting the packet data from among multiple routes for transmitting the packet data to a receiving terminal based on characteristics of the converted packet data, and transmits the received packet data via the determined route.

Images