Communication terminal, communication method, and program

Abstract

To detect the reception of a packet that the edge terminal is not to be received, and to encourage improvement of a network environment in a communication terminal that is an edge terminal connected to a network.SOLUTION: A communication terminal is connected to a network and includes a determination unit that determines whether a packet received from a network is a packet transmitted and received between relay devices, and a notification unit that notifies the reception of a packet transmitted and received between the relay devices when the packet received from the network is a packet transmitted and received between the relay devices.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a communication terminal, a communication method, and a program. [Background technology]

[0002] There is a technology for analyzing network packets to detect protocol defects. For example, an automatic defect detection device is known that detects a defective transmission / reception control process based on the results of comparing status information about the packet transmission / reception state with defect information that characterizes the defect in the transmission / reception control process (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0003] The conventional technology disclosed in Patent Document 1 detects defects by checking the format of the TCP (Transmission Control Protocol). However, this method alone cannot detect, for example, the reception of a packet that an edge terminal should not have received due to a routing error, and cannot prompt improvement of the network environment.

[0004] One embodiment of the present invention has been made in consideration of the above-mentioned problems, and enables a communication terminal that is an edge terminal connected to a network to detect that it has received a packet that the edge terminal should not have received, thereby encouraging improvements to the network environment. [Means for solving the problem]

[0005] In order to solve the above problem, a communication terminal according to one embodiment of the present invention is a communication terminal connected to a network, and has a determination unit that determines whether a packet received from the network is a packet transmitted and received between relay devices, and a notification unit that, if the packet received from the network is a packet transmitted and received between the relay devices, notifies the reception of a packet transmitted and received between the relay devices. [Effects of the Invention]

[0006] According to one embodiment of the present invention, a communication terminal that is an edge terminal connected to a network can detect that it has received a packet that the edge terminal should not have received, and can encourage improvements to the network environment. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a diagram illustrating an example of a hardware configuration of a communication terminal according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a functional configuration of a communication terminal according to an embodiment. [Figure 3] FIG. 2 is a diagram illustrating an example of a functional configuration of a packet analysis unit according to an embodiment. [Figure 4] 10 is a flowchart illustrating an overview of a packet analysis process according to an embodiment. [Figure 5] 10 is a flowchart illustrating an example of a packet analysis process according to the first embodiment. [Figure 6] FIG. 2 is a diagram illustrating an example of a packet to which a VLAN tag is added according to the first embodiment. [Figure 7] FIG. 1 is a diagram (1) showing an example of a display screen according to the first embodiment. [Figure 8] FIG. 2 is a diagram (2) showing an example of a display screen according to the first embodiment. [Figure 9] 10 is a flowchart illustrating an example of a packet analysis process according to the second embodiment. [Figure 10] FIG. 10 is a diagram illustrating an example of a packet to which an MLPS label is added according to the second embodiment. [Figure 11] FIG. 10 is a diagram showing an example of a display screen according to the second embodiment. [Figure 12] 13 is a flowchart illustrating an example of a packet analysis process according to the third embodiment. [Figure 13] FIG. 11 is a diagram illustrating an example of a packet to which header information of a routing protocol according to the third embodiment is added. [Figure 14] FIG. 11 is a diagram showing an example of a display screen according to the third embodiment. [Figure 15] FIG. 10 is a sequence diagram illustrating an example of processing of a communication terminal according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0009] <Communication terminal configuration> 1 is a diagram illustrating an example of the hardware configuration of a communication terminal according to an embodiment. The communication terminal 100 is an edge terminal connected to a network. As an example, the communication terminal 100 is an image forming device that performs image forming processes such as printing, scanning, and copying. However, the communication terminal 100 is not limited to an image forming device, and may be any of various terminal devices connected to a network.

[0010] For example, the communication terminal 100 may be an electronic device such as a video conferencing device, a projector, or an IWB (Interactive White Board: an electronic white board with a blackboard function that allows mutual communication). The communication terminal 100 may also be a display device such as a digital signage or a HUD (Head Up Display) device. Furthermore, the communication terminal 100 may also be an industrial machine, an imaging device, a sound collecting device, a medical device, a network home appliance, an automobile (Connected Car), an in-vehicle device, or the like.

[0011] In the example of FIG. 1, the communication terminal 100 includes a CPU (Central Processing Unit) 101, a RAM (Random Access Memory) 102, a flash memory 103, a display device 104, an input device 105, a communication I / F (Interface) 106, a bus B, and the like.

[0012] The CPU 101 is a processor (arithmetic unit) that controls the communication terminal 100 by executing a predetermined program stored in a storage medium such as the flash memory 103. The RAM 102 is a volatile memory used as a work area or the like for the CPU 101. The flash memory 103 is a non-volatile memory that stores, for example, an OS (Operating System), programs such as applications, various data, setting information, and the like.

[0013] The display device 104 is a display device such as a liquid crystal display or an organic electroluminescence (EL) display that displays various display screens. The input device 105 is an input device such as a touch panel or operation buttons that accepts user input. The display device 104 and the input device 105 may be a display input device such as a touch panel display.

[0014] The communication I / F 106 is an interface for connecting the communication terminal 100 to the network N. The bus B is commonly connected to the above components, and transmits, for example, address signals, data signals, and various control signals.

[0015] 1 is an example of the hardware configuration of communication terminal 100. For example, if communication terminal 100 is an image forming device, communication terminal 100 further includes a printer that prints print data on a print medium, a scanner that scans documents, etc. Furthermore, if communication terminal 100 is a projector, communication terminal 100 further includes an image projection device that projects an image, etc.

[0016] <Functional configuration> Fig. 2 is a diagram showing an example of the functional configuration of a communication terminal according to an embodiment. The communication terminal 100 realizes, for example, each functional configuration shown in Fig. 2 by executing a predetermined program stored in a storage medium such as a flash memory 103. In the example of Fig. 2, the communication terminal 100 has each functional configuration such as a communication unit 201, a packet analysis unit 202, a display unit 203, and a process execution unit 204. Note that at least a part of each of the above functional configurations may be realized by hardware.

[0017] The communication unit 201 connects the communication terminal 100 to the network N using the communication I / F 106, and executes communication processing for transmitting and receiving packets to and from other devices.

[0018] The packet analysis unit 202 executes an analysis process to analyze a packet received by the communication unit 201. For example, as shown in FIG. 3, the packet analysis unit 202 includes a determination unit 301, a notification unit 302, and a destination filter unit 303.

[0019] The determination unit 301 executes a determination process to determine whether a packet received by the communication unit 201 from the network N is a packet transmitted and received between relay devices. Here, packets transmitted and received between relay devices include, for example, packets with a VLAN (Virtual Local Area Network) tag attached, packets with an MPLS label attached, or packets with header information of a routing protocol attached. These packets are normally transmitted and received only between relay devices such as switches or routers, and are not received by the communication terminal 100, which is an edge terminal.

[0020] Note that the relay device is not limited to a switch or a router, but may include various other network devices such as a gateway having the same function as a switch or a router, or an access point.

[0021] If the packet received by communication unit 201 from the network is a packet transmitted and received between relay devices, notification unit 302 executes a notification process to notify the user that the packet transmitted and received between relay devices has been received. For example, notification unit 302 notifies the user that the packet transmitted and received between relay devices has been received by displaying a message or the like on the display screen displayed by display unit 203. As another example, notification unit 302 may notify an administrator terminal used by an administrator, an administrator's email address, or the like, of information indicating that communication terminal 100 has received a packet transmitted and received between relay devices.

[0022] The destination filter unit 303 executes destination filtering processing to selectively output packets to be processed by the communication terminal 100 from among packets received by the communication unit 201 from the network. For example, the destination filter unit 303 determines whether or not the packets received by the communication unit 201 are packets to be processed by the communication terminal 100, and discards packets other than those to be processed by the communication terminal 100.

[0023] 3 is an example. For example, the notification unit 302 or the destination filter unit 303 may be provided outside the packet analysis unit 202. The destination filter unit 303 may be realized by hardware, for example. Furthermore, the function of the destination filter unit 303 may be included in the determination unit 301.

[0024] 2, the functional configuration of communication terminal 100 will be further described. Display unit 203 executes a display process for displaying various display screens on display device 104. For example, if communication terminal 100 is an image forming device, display unit 203 displays a display screen such as an operation screen or a setting screen of the image forming device on display device 104.

[0025] The notification unit 302 can use the display unit 203 to display (notify) on the display screen information indicating that a packet transmitted and received between relay devices has been received.

[0026] The processing execution unit 204 executes various processes based on the received packet. For example, if the packet output from the packet analysis unit 202 is a request packet requesting specific information, the processing execution unit 204 generates a response packet that provides the specific information and transmits the generated response packet to the sender via the communication unit 201. Furthermore, if the communication terminal 100 is an image forming apparatus and the packet output from the packet analysis unit 202 is a request packet requesting image formation processing, the processing execution unit 204 executes the requested image formation processing.

[0027] <Processing flow> Next, the processing flow of the communication method according to this embodiment will be described.

[0028] (Packet analysis processing) 4 is a flowchart showing an outline of a packet analysis process according to an embodiment. This process shows an outline of the packet analysis process executed by the packet analysis unit 202 described in FIG. 3 when the communication unit 201 receives a packet, for example.

[0029] In steps S401 and S402, the determination unit 301 analyzes the packet received by the communication unit 201 and determines whether it is a packet transmitted or received between relay devices. For example, if the received packet is a packet transmitted or received only between switches or a packet transmitted or received only between routers, the determination unit 301 determines that the received packet is a packet transmitted or received between relay devices. Specific determination methods will be described later using multiple exemplary embodiments.

[0030] If the received packet is a packet transmitted or received between relay devices, the determination unit 301 shifts the process to step S403. On the other hand, if the received packet is not a packet transmitted or received between relay devices, the determination unit 301 shifts the process to step S404.

[0031] In step S403, the notification unit 302 notifies that a packet transmitted and received between relay devices has been received. For example, the notification unit 302 uses the display unit 203 to display information indicating that a packet transmitted and received between relay devices has been received on a display screen displayed by the display unit 203. Alternatively, the notification unit 302 may use the communication unit 201 to transmit information indicating that a packet transmitted and received between relay devices has been received to an administrator terminal used by the administrator, the administrator's email address, or the like.

[0032] In step S404, destination filter unit 303 determines whether the packet received by communication unit 201 is a packet to be processed by communication terminal 100. If the packet is to be processed by communication terminal 100, destination filter unit 303 shifts the process to step S404. On the other hand, if the packet is not to be processed by communication terminal 100, destination filter unit 303 does not output the received packet and ends the process in FIG. 4.

[0033] In step S405, the destination filter unit 303 outputs the packet received by the communication unit 201 to a predetermined output destination such as the process execution unit 204.

[0034] Through the process of FIG. 4, the packet analysis unit 202 can detect that a packet that should not have been received by the communication terminal 100, which is an edge terminal, has been received, and can notify the user, administrator, or the like.

[0035] Next, a more specific example of the packet analysis process executed by the packet analysis unit 202 will be described.

[0036] [First embodiment] (Packet analysis process 1) 5 is a flowchart showing an example of packet analysis processing according to the first embodiment. This processing shows a specific example of packet analysis processing executed by the packet analysis unit 202 when the communication unit 201 receives a packet, for example.

[0037] In step S501, the determination unit 301 reads the header of the packet received by the communication unit 201.

[0038] In step S502, the determination unit 301 determines whether a VLAN tag is added to the header. The VLAN tag is tag information used in tagged VLAN (Virtual LAN).

[0039] Fig. 6 is a diagram showing an example of a packet to which a VLAN tag has been added according to the first embodiment. Fig. 6 shows examples of the frame formats of a normal Ethernet (registered trademark) frame 610 and an Ethernet frame 620 to which a VLAN tag has been added. Note that the Ethernet frame is an example of a packet.

[0040] 6, a normal Ethernet frame 610 includes an Ethernet header (Layer 2 header) 616, such as a destination MAC address 611, a source MAC address 612, and a type 613. On the other hand, an Ethernet frame 620 with a VLAN tag added has a VLAN tag 621 added between the source MAC address 612 and the type 613 in the Ethernet header.

[0041] This VLAN tag 621 includes information such as a Tag Protocol Identifier (TPID) 622, a Priority Code Point (PCP) 623, a Canonical Format Indicator (CFI) 624, and a VLAN ID (VID) 625, for example.

[0042] In tagged VLAN, when a frame is sent over a link between switches, a VLAN tag 621 is added to the frame. Note that this VLAN tag 621 is deleted by a switch when the frame is sent to, for example, the network N to which the communication terminal 100 is connected. Therefore, if the VLAN tag 621 is added to a packet received by the communication unit 201, there is a possibility that a problem may occur in the construction of the network environment.

[0043] If the VLAN tag 621 is added to the header, the determination unit 301 shifts the process to step S503. On the other hand, if the VLAN tag 621 is not added to the header, the determination unit 301 shifts the process to step S504.

[0044] In step S503, the notification unit 302 uses the display unit 203 to cause the display device 104 to display a display screen indicating that a packet transmitted and received between relay devices has been received.

[0045] Fig. 7 is a diagram (1) showing an example of a display screen according to the first embodiment. This display screen 700 shows an image of an operation screen when communication terminal 100 is an image forming device. In the example of Fig. 7, the display screen displays a plurality of selection buttons 701 for selecting a plurality of applications (hereinafter referred to as apps). Note that when communication terminal 100 is an image forming device, the plurality of applications include, for example, a print app, a scan app, or a copy app.

[0046] In the example of FIG. 7, the display screen 700 displays a message 702 saying, "Packets exchanged between routers and switches have been received. Please check your network environment." Note that this message 702 is an example of a message indicating that a packet exchanged between relay devices has been received.

[0047] Preferably, the user can select message 702 on display screen 700 to display, for example, display screen 800 as shown in Fig. 8. In the example of Fig. 8, display screen 800 displays message 801 indicating what kind of "packet transmitted and received between relay devices" has been received, and message 802 urging the user to check the network environment. These messages 801 and 802 enable communication terminal 100 to urge the user to improve the network environment.

[0048] Preferably, this display screen 800 includes a message 803 indicating how to deal with the problem. This message 803 enables the communication terminal 100 to make it easier for the user or the like to improve the network environment.

[0049] 5, the description of the flowchart will continue. In step S504, destination filter unit 303 determines whether the packet received by communication unit 201 is a packet to be processed by communication terminal 100. If the packet is to be processed by communication terminal 100, destination filter unit 303 causes the process to proceed to step S505. On the other hand, if the packet is not to be processed by communication terminal 100, destination filter unit 303 ends the process in FIG.

[0050] In step S 505 , the destination filter unit 303 outputs the packet received by the communication unit 201 to the process execution unit 204 .

[0051] By the process of Figure 5, the communication terminal 100 analyzes the received packet, detects that it has received a "packet with a VLAN tag attached" that should not have been received, and can urge the user or the like to improve the network environment.

[0052] If a VLAN tag is added to the received packet, the destination filter unit 303 may not be able to correctly process the packet that should be processed by the communication terminal 100, and may end up discarding the packet addressed to the communication terminal 100. If this state continues, the user may not be able to use the communication terminal 100 via the network.

[0053] However, the communication terminal 100 according to this embodiment can prompt users to improve the network environment, thereby reducing the occurrence of problems caused by the network environment. In order to obtain the above-mentioned effects, in each embodiment of the present invention, a determination unit 301 is provided before the destination filter unit 303.

[0054] [Second embodiment] (Packet analysis process 2) 9 is a flowchart showing an example of packet analysis processing according to the second embodiment. This processing shows another example of packet analysis processing executed by the packet analysis unit 202 when the communication unit 201 receives a packet, for example.

[0055] In step S901, the determination unit 301 reads the header of the packet received by the communication unit 201.

[0056] In step S902, the determination unit 301 determines whether an MLPS label has been added to the header. MLPS (Multi-Protocol Label Switching) is a packet transfer technology that uses tags called labels. MLPS allows data to be switched by adding labels corresponding to various protocols.

[0057] 10 is a diagram showing an example of a packet to which an MLPS label has been added according to the second embodiment. Note that a packet 1000 to which an MLPS label has been added is an example of a packet transmitted and received between relay devices.

[0058] There are two types of MPLS labels: frame mode (packet mode) and cell mode, and Figure 10 shows the packet structure when used in frame mode. In frame mode, an MPLS label 1002 is added between an Ethernet header 1001 and a payload 1003 that includes an IP header. The MPLS label 1002 is sometimes called an MPLS header.

[0059] This MPLS label 1002 includes information such as Label 1011, EXP (Experimental) 1012, S 1013, and TTL (Time-to-live) 1014. Label 1011 has a 20-bit area and stores label information distributed by an LER (Label Edge Router) or LSR (Label Switch Router) using a label distribution protocol. EXP 1012 is an experimental area with a 3-bit area. It is currently used to map IP precedence information and for QoS (Quality of Service) purposes. S (Stack Bit) 1013 has a 1-bit area and indicates whether another MPLS label follows the MPLS label 1002. TTL 1014 has an 8-bit area and is used to prevent loops.

[0060] MPLS is enabled by the LER and LSR, but not by the customer router. Therefore, if the MPLS label 1002 is added to the packet received by the communication unit 201, there may be a problem in the construction of the network environment.

[0061] If the MPLS label 1002 is added to the header, the determining unit 301 shifts the process to step S903. On the other hand, if the MPLS label 1002 is not added to the header, the determining unit 301 shifts the process to step S904.

[0062] In step S903, the notification unit 302 uses the display unit 203 to cause the display device 104 to display a display screen indicating that a packet transmitted and received between relay devices has been received. For example, the notification unit 302 uses the display unit 203 to cause the display device 104 to display a display screen 700 as shown in FIG.

[0063] Preferably, the user can select message 702 on display screen 700 to display, for example, display screen 1100 as shown in Fig. 11. In the example of Fig. 11, display screen 1100 displays message 1101 indicating what kind of "packet transmitted and received between relay devices" has been received, and message 1102 urging the user to check the network environment. These messages 1101 and 1102 enable communication terminal 100 to urge the user to improve the network environment.

[0064] Preferably, this display screen 1100 includes a message 1103 indicating how to deal with the problem. This message 1103 enables the communication terminal 100 to make it easier for the user or the like to improve the network environment.

[0065] 9, the description of the flowchart will continue. In step S904, destination filter unit 303 determines whether the packet received by communication unit 201 is a packet to be processed by communication terminal 100. If the packet is to be processed by communication terminal 100, destination filter unit 303 causes the process to proceed to step S905. On the other hand, if the packet is not to be processed by communication terminal 100, destination filter unit 303 does not output the received packet and ends the process in FIG. 9.

[0066] In step S905, the destination filter unit 303 outputs the packet received by the communication unit 201 to the process execution unit 204 and the like.

[0067] By the process of FIG. 9, communication terminal 100 analyzes the received packet, detects that it has received a "packet with an MLPS label attached" that should not have been received, and can prompt the user to improve the network environment.

[0068] If an MLPS label is added to the received packet, the destination filter unit 303 may not be able to correctly process the packet that should be processed by the communication terminal 100, and may end up discarding the packet addressed to the communication terminal 100. If this state continues, the user may not be able to use the communication terminal 100 via the network.

[0069] However, the communication terminal 100 according to this embodiment can prompt the user to improve the network environment, and as a result, it is possible to reduce the occurrence of troubles caused by the network environment. Note that the second embodiment can be applied in combination with the first embodiment.

[0070] [Third embodiment] (Packet analysis process 3) 12 is a flowchart showing an example of packet analysis processing according to the third embodiment. This processing shows another example of packet analysis processing executed by the packet analysis unit 202 when the communication unit 201 receives a packet, for example.

[0071] In step S 1201 , the determination unit 301 reads the header of the packet received by the communication unit 201 .

[0072] In step S902, the determination unit 301 determines whether header information of a routing protocol is added to the header. For example, the determination unit 301 determines whether header information of the RIP (Routing Information Protocol), which is an example of a routing protocol, is added. The RIP protocol is a type of IGP (Interior Gateway Protocol), which is a routing protocol.

[0073] 13 is a diagram showing an example of a packet to which header information of a routing protocol has been added according to the third embodiment. Note that a packet 1300 to which header information of a routing protocol has been added is an example of a packet transmitted and received between relay devices.

[0074] As shown in FIG. 13, an Ethernet header 1301 and an IP header 1302 are followed by a RIP protocol 1303, which is an example of header information of a routing protocol.

[0075] The RIP protocol 1303 includes information such as a command 1311 , a version 1312 , an address family identifier 1313 , a route tag 1314 , an IP address 1315 , a subnet mask 1316 , a next hop 1317 , and a metric 1318 .

[0076] Command 1311 has a 1-byte field, and if set to 1 it indicates a request, and if set to 2 it indicates a response. Version 1312 has a 1-byte field, and indicates the version of RIP. Note that Fig. 13 shows the packet format of RIP version 2.

[0077] The address family identifier 1313 has a 2-byte area and is used to indicate the format of the route. For IP, 2 is set. The route tag 1314 has a 3-byte area and can be used for route redistribution. It is generally set to 0. The IP address 1315 has a 4-byte area and is set to the destination route or host address.

[0078] The subnet mask 1316 has a 4-byte area, and a subnet mask for the route in the IP address field is set. The next hop 1317 has a 4-byte area, and a gateway address is set. For example, if 0.0.0.0 is set, the source IP address becomes the gateway address. The metric 1318 has a 4-byte area, and the number of hops is set.

[0079] RIP is a routing protocol used for path control in routing between relay devices such as switches or routers. Therefore, if the RIP protocol 1303 is added to a packet received by the communication unit 201, there is a possibility that there may be a problem in constructing a network environment.

[0080] If header information of a routing protocol such as the RIP protocol 1303 is added to the header, the determination unit 301 shifts the process to step S1203. On the other hand, if header information of a routing protocol is not added to the header, the determination unit 301 shifts the process to step S1204.

[0081] In step S1203, the notification unit 302 uses the display unit 203 to cause the display device 104 to display a display screen indicating that a packet transmitted and received between relay devices has been received. For example, the notification unit 302 uses the display unit 203 to cause the display device 104 to display a display screen 700 as shown in FIG.

[0082] Preferably, the user can select message 702 on display screen 700 to display, for example, display screen 1400 as shown in Fig. 14. In the example of Fig. 14, display screen 1400 displays message 1401 indicating what kind of "packet transmitted and received between relay devices" has been received, message 1402 urging the user to check the network environment, etc. These messages 1401 and 1402 enable communication terminal 100 to urge the user to improve the network environment.

[0083] Preferably, this display screen 1400 includes a message 1103 indicating how to deal with the problem. This message 1103 enables the communication terminal 100 to make it easier for the user or the like to improve the network environment.

[0084] 12, the description of the flowchart will continue. In step S1204, destination filter unit 303 determines whether the packet received by communication unit 201 is a packet to be processed by communication terminal 100. If the packet is to be processed by communication terminal 100, destination filter unit 303 causes the process to proceed to step S1205. On the other hand, if the packet is not to be processed by communication terminal 100, destination filter unit 303 does not output the received packet and ends the process of FIG. 12.

[0085] In step S1205, the destination filter unit 303 outputs the packet received by the communication unit 201 to the process execution unit 204 and the like.

[0086] By the process of Figure 12, the communication terminal 100 analyzes the received packet, detects that it has received a "packet with routing protocol header information attached" that should not have been received, and can urge the user to improve the network environment.

[0087] If header information of a routing protocol is added to the received packet, the destination filter unit 303 may not be able to correctly process the packet that should be processed by the communication terminal 100, and may end up discarding the packet addressed to the communication terminal 100. If this state continues, the user may not be able to use the communication terminal 100 via the network.

[0088] However, the communication terminal 100 according to this embodiment can prompt the user to improve the network environment, thereby reducing the occurrence of troubles caused by the network environment. The third embodiment can be applied in combination with the first embodiment, the second embodiment, or both the first and second embodiments.

[0089] <Communication terminal processing> 15 is a sequence diagram illustrating an example of processing performed by a communication terminal according to an embodiment. This processing illustrates an example of processing performed when a packet is received by the communication terminal 100 having the functional configuration described in FIG. 2, for example.

[0090] In steps S1501 and S1502, when the communication unit 201 receives a packet from the network N, it outputs the received packet to the packet analysis unit 202.

[0091] In steps S1503 and S1504, the packet analysis unit 202 analyzes the received packet and determines whether it is a packet transmitted or received between relay devices. This process can be, for example, the processes of steps S501 and S502 in Fig. 5, steps S901 and S902 in Fig. 9, steps S1201 and S1202 in Fig. 12, or any combination of these processes.

[0092] If the received packet is a packet transmitted and received between relay devices, the communication terminal 100 executes the processes of steps S1511 and S1512.

[0093] In step S1511, the packet analysis unit 202 notifies the display unit 203 that a packet transmitted and received between relay devices has been received.

[0094] In step S1512, the display unit 203 displays that a packet transmitted and received between relay devices has been received. For example, the display unit 203 displays a display screen 700 as shown in FIG.

[0095] In step S1505, packet analysis unit 202 determines whether the received packet is a packet to be processed by communication terminal 100. If the received packet is a packet to be processed by communication terminal 100, communication terminal 100 executes the processes of steps S1521 and S1522.

[0096] In step S1521 , the packet analysis unit 202 outputs the packet to be processed by the communication terminal 100 to the process execution unit 204 .

[0097] In step S1522, the processing execution unit 204 executes processing on the packet to be processed by the communication terminal 100.

[0098] In this way, the communication terminal 100 of this embodiment analyzes the received packet to determine whether the "packet exchanged between relay devices" has reached an edge terminal (communication terminal 100) that should not have received it.

[0099] Furthermore, if the "packets exchanged between relay devices" reach the edge terminal, the communication terminal 100 determines that the routing settings are incorrect and that there may be a problem in the network environment.

[0100] Furthermore, if the communication terminal 100 determines that the routing settings are incorrect and that there is a problem in the network environment, it notifies the user that the routing settings are incorrect and that there may be a problem in the network environment, and urges the user to improve the network environment.

[0101] In this way, according to this embodiment, it becomes possible for a communication terminal 100, which is an edge terminal connected to a network, to detect that it has received a packet that the edge terminal should not have received, and to encourage improvement of the network environment.

[0102] <Supplementary information> Each function of each embodiment described above can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and conventional circuit modules designed to perform each of the functions described above.

[0103] <Additional Notes> This specification discloses the following communication terminals, communication methods, and programs. (Appendix 1) A communication terminal connected to a network, a determination unit that determines whether a packet received from the network is a packet transmitted or received between relay devices; a notification unit that notifies the reception of a packet transmitted and received between the relay devices when the packet received from the network is a packet transmitted and received between the relay devices; A communication terminal having: (Appendix 2) 2. The communication terminal according to claim 1, wherein the packets transmitted and received between the relay devices include packets transmitted and received only between switches or packets transmitted and received only between routers. (Appendix 3) 3. The communication terminal according to claim 1, wherein packets transmitted and received between the relay devices include packets to which a VLAN tag is added. (Appendix 4) 4. The communication terminal according to claim 1, wherein packets transmitted and received between the relay devices include packets to which an MPLS label is added. (Appendix 5) The communication terminal according to any one of Supplementary Note 1 to Supplementary Note 4, wherein packets transmitted and received between the relay devices include packets to which header information of a routing protocol is added. (Appendix 6) A display unit that displays a display screen is provided. 6. The communication terminal according to claim 1, wherein the notification unit notifies, using the display screen, that a packet transmitted and received between the relay devices has been received. (Appendix 7) 7. The communication terminal according to claim 6, wherein the notification unit notifies, using the display screen, a response method for receiving a packet transmitted and received between the relay devices. (Appendix 8) a destination filter unit that executes a filtering process to selectively output packets to be processed by the communication terminal among packets received from the network; the determination unit determines whether the packet received from the network is a packet transmitted or received between relay devices before performing the filtering process. A communication terminal according to any one of Supplementary notes 1 to 7. (Appendix 9) A communication terminal connected to a network A process of determining whether a packet received from the network is a packet transmitted or received between relay devices; If the packet received from the network is a packet transmitted between the relay devices, a process of notifying that the packet transmitted between the relay devices has been received; A communication method that performs the following. (Appendix 10) A communication terminal connected to the network A process of determining whether a packet received from the network is a packet transmitted or received between relay devices; If the packet received from the network is a packet transmitted between the relay devices, a process of notifying that the packet transmitted between the relay devices has been received; A program that executes.

[0104] Although the embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various modifications and applications are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0105] 100 communication terminal 201 Communications Department 202 Packet Analysis Unit 203 Display section 204 Processing Execution Unit 301 Judgment section 302 Notification Department 303 Destination Filter Part 621 VLAN tag 700, 800, 1100, 1400 display screen 1002 MPLS labels 1303 RIP protocol (header information of routing protocol) 1303 N Network [Prior art documents] [Patent documents]

[0106] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-200773

Claims

1. A communication terminal connected to a network, a determination unit that determines whether a packet received from the network is a packet transmitted or received between relay devices; a notification unit that notifies the reception of a packet transmitted between the relay devices when the packet received from the network is a packet transmitted between the relay devices; A communication terminal having:

2. 2. The communication terminal according to claim 1, wherein the packets transmitted and received between the relay devices include packets transmitted and received only between switches or packets transmitted and received only between routers.

3. 3. The communication terminal according to claim 1, wherein packets transmitted and received between said relay devices include packets to which a VLAN tag is added.

4. 3. The communication terminal according to claim 1, wherein packets transmitted and received between said relay devices include packets to which an MPLS label is added.

5. 3. The communication terminal according to claim 1, wherein packets transmitted and received between said relay devices include packets to which header information of a routing protocol is added.

6. A display unit that displays a display screen is provided. The communication terminal according to claim 1 , wherein the notification unit notifies, using the display screen, that a packet transmitted and received between the relay devices has been received.

7. The communication terminal according to claim 6 , wherein the notification unit notifies, using the display screen, of a method of dealing with reception of a packet transmitted and received between the relay devices.

8. a destination filter unit that executes a filtering process to selectively output packets to be processed by the communication terminal among packets received from the network; the determination unit determines whether the packet received from the network is a packet transmitted or received between relay devices before performing the filtering process.

3. The communication terminal according to claim 1 or 2.

9. A communication terminal connected to a network A process of determining whether a packet received from the network is a packet transmitted or received between relay devices; If the packet received from the network is a packet transmitted between the relay devices, a process of notifying that the packet transmitted between the relay devices has been received; A communication method that performs the following.

10. A communication terminal connected to the network A process of determining whether a packet received from the network is a packet transmitted or received between relay devices; If the packet received from the network is a packet transmitted between the relay devices, a process of notifying that the packet transmitted between the relay devices has been received; A program that executes.

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