JP6402574B2 - Information processing system and information processing method - Google Patents

Description

  The present invention relates to an information processing system and an information processing method.

Conventionally, in an IP (Internet Protocol) network, for example, a PING command, a TRACE ROUTE command, and the like are often used for communication communication confirmation and communication path information collection.

International Publication No. 2007/119635

  However, in recent years, with the complexity of networks and the introduction of SDN (Software Defined Network), it is difficult to confirm communication communication and collect information on communication paths with conventional methods. For example, in SDN, a communication path is set for at least a packet group having the same destination and source IP address, protocol number, destination and source port number. A packet group having at least the same destination and source IP address, protocol number, destination and source port number is hereinafter referred to as a flow.

For example, the PING and HTTP (Hypertext Transfer Protocol) services are recognized as different flows because the protocols are different. For this reason, even if the source device and the destination device are the same between the PING and HTTP (Hypertext Transfer Protocol) services, different flows may be set because the flows are different. Therefore, when the source device and the destination device are the same, even if the destination device is reachable by PING, the route is different in the HTTP service, for example, a failure occurs on the route. Otherwise, it may become unreachable.

  One aspect of the present invention is a communication of a packet group having predetermined packet identification information in a network in which packet transfer is performed based on route information identified by packet identification information obtained from a combination of information included in packet headers. An object is to provide an information processing system and an information processing method capable of specifying a route.

  One aspect of the present invention includes a plurality of relay apparatuses that transfer packets based on path information identified by packet identification information obtained from a combination of information included in packet headers, and predetermined packet identification information An information processing system including a test device that searches for a route of a packet group. When the test apparatus receives a response to the search frame including identification information of the relay apparatus from any of a plurality of relay apparatuses and a transmission unit that transmits the search frame having predetermined packet identification information, the test apparatus And a control unit that collects identification information of a transmission source relay device as a part of information indicating a route of the packet group. Each of the plurality of relay devices, when receiving a search frame, based on the transmission unit that transmits a response to the search frame including the identification information of its own device to the test device, and predetermined packet identification information that the search frame has, And a transfer unit for transferring the search frame.

  According to the information processing system and the information processing method disclosed herein, in a network in which packet forwarding is performed based on path information identified by packet identification information obtained from a combination of information included in a packet header, a predetermined packet It is possible to specify a communication path of a packet group having identification information.

It is a figure which shows an example of a structure of the network system which concerns on 1st Embodiment. It is an example of the hardware constitutions of a test terminal. It is a figure which shows an example of a function structure of a test terminal. It is a figure which shows an example of a function structure of a trace corresponding | compatible switch. It is an example of the frame format of a search frame. It is an example of the frame format of a search frame response. It is an example of the frame format of a TRACE PING frame. It is an example of the frame format of a TRACE PING response frame. It is an example of the search route list which a test terminal uses in route search. It is an example of the entry information of the apparatus recorded on the search route list. It is an example of the flowchart of the route search process of the route search algorithm control part of a test terminal. It is an example of the flowchart of a search frame response reception process. It is an example of the flowchart of a TRACE PING response reception process. It is an example of the flowchart of D plane packet reception processing of a trace corresponding switch. It is an example of the flowchart of a process of a trace corresponding | compatible switch when the packet addressed to an own local port is received via M plane. It is a figure which shows an example of the route search process sequence in the network system which concerns on 1st Embodiment. It is a figure which shows an example of the route search process sequence in the network system which concerns on 1st Embodiment. It is a figure which shows an example of the route search process sequence in the network system which concerns on 1st Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The configuration of the following embodiment is an exemplification, and the present invention is not limited to the configuration of the embodiment.

<First Embodiment>
FIG. 1 is a diagram illustrating an example of a configuration of a network system 100 according to the first embodiment. Network system 100 includes an SDN network and a network other than the SDN network. Examples of networks other than the SDN network include an IP network. The network system 100 includes a test terminal 2 and a host 3. The SDN network includes a plurality of SDN switches 1.

The SDN network includes a D plane (Data Plane) for exchanging user data, an M plane (Management Plane) for exchanging management data, and a C plane for exchanging control data between the SDN switch 1 and an SDN controller (not shown). (Control Plane).
The D plane, M plane, and C plane are physically or logically independent networks. The SDN switch 1 participates in any of the D plane, M plane, and C plane, and has a physical or logical interface that connects to each network. The test terminal 2 participates in the D plane and the M plane, and has a physical or logical interface connected to each network. In the first embodiment, the M plane is prepared in the SDN network, but the M plane is not essential, and management data may be exchanged through the D plane.

  The SDN switch 1 holds a flow table set by an SDN controller (not shown). The flow table includes, for example, correspondence between packet identification information and processing contents for the packet. The packet identification information is information such as a destination and a transmission source IP address, a protocol number, a destination and a transmission source port number included in the packet. Examples of processing contents for packets in the flow table include transfer, discard, and packet processing. When the processing content for the packet is transfer processing, information on the output port is included. That is, the flow table includes route information. When the SDN switch 1 receives the packet, the SDN switch 1 determines an output port based on the packet identification information of the received packet and the flow table, and outputs the received packet from the output port.

  The test terminal 2 is a terminal at the start point of the target flow for route search. The host 3 is a destination terminal of the target flow for route search. The SDN switch 1 corresponding to the path trace method of the first embodiment is referred to as a trace corresponding switch. Further, the SDN switch 1 that does not support the route trace method of the first embodiment and the relay devices in other networks such as the layer 3 router are collectively referred to as a trace non-compatible switch. Henceforth, the code | symbol of a switch corresponding to a trace shall be 1. When there is no particular distinction between the trace compatible switch and the trace non-compatible SDN switch, they are denoted as SDN switch 1.

  The trace corresponding switch 1 closest to the test terminal 2 existing on the path from the test terminal 2 to the host 3 of the target flow and the trace corresponding switch 1 closest to the trace corresponding switch 1 existing on the path are adjacent trace compatible. This is called a switch.

  (1) In the first embodiment, a search frame is used for route search. The search frame holds, for example, the same packet identification information as the packet of the route search target flow, and identification information for determining that it is a search frame.

  In the route search process, the test terminal 2 first transmits a search frame to the host 3. In the SDN network, the search frame is transferred by the SDN switch 1 according to the packet identification information of the search frame and the flow table. When the trace corresponding switch 1 receives the search frame, it transmits a search frame response including its own information to the test terminal 2 as a response to the search frame.

  The search frame response is a frame for notifying the test terminal 2 of the information of the trace correspondence switch 1 itself. The information of the trace switch 1 itself includes, for example, the IP address of the M plane or D plane, which is its identification information. The test terminal 2 records the identification information of the trace corresponding switch 1 included in the received search frame response in the search path list. The test terminal 2 can detect the trace correspondence switch 1 located on the route to the destination of the route search target flow by collecting the identification information of the trace correspondence switch 1 that is the transmission source of the search frame response.

In addition, the search frame is a packet having the same packet identification information as the packet of the route search target flow, and in order to obtain a response from the host 3, in the first embodiment, TCP
A SYN packet is used. Therefore, when the destination host 3 receives the search frame, the host 3 sends a TCP SYN ACK packet as a response to the packet of the route search target flow in the same manner as when the TCP SYN packet of the route search target flow is received. Is transmitted to the test terminal 2 of the transmission source. By receiving the TCP SYN ACK packet from the host 3, the test terminal 2 can confirm the communication with the destination host 3, and ends the route search process.

  (2) The search frame has the same packet identification information as the flow of the route search target in order to specify the actual route, and is transferred on the D plane. For this reason, the communication related to the route search as described above may affect the communication of the service flowing through the D plane. In order to suppress the influence on the communication of the service flowing through the D plane by the communication related to the route search, in the first embodiment, the trace correspondence switch 1 does not immediately transfer the received search frame, but uses the search frame as a buffer. Temporarily hold and temporarily hold the process. The temporary holding of the search frame in the buffer is hereinafter referred to as HOLD.

  In the first embodiment, the protocol for the test terminal 2 to instruct the trace corresponding switch 1 to process the HOLD search frame is defined as TRACE PING. Hereinafter, TRACE PING is abbreviated as TP. For example, the TRACE PING instructs the trace correspondence switch 1 to transfer and discard the HOLD search frame and to collect information on processing performed on the search frame.

  When the test terminal 2 receives the search frame response from the trace correspondence switch 1, the test terminal 2 transmits a TP frame including a transfer instruction of the search frame to be held to the trace correspondence switch 1 that is the transmission source of the search frame response. When receiving the TP frame including the search frame transfer instruction, the trace correspondence switch 1 performs processing based on the packet identification information and the flow table for the HOLD search frame, and transfers the search frame.

  The exchange of the search frame, the search frame response, and the TP frame as described above is performed for each trace corresponding switch 1 that has received the search frame. Therefore, in the first embodiment, the search frame is HOLDed by HOP-BY-HOP, and sequentially relayed by a transfer instruction using a TP frame.

  When receiving the search frame response to the search frame, the test terminal 2 determines whether there is an abnormality that may cause the search frame to stay in the network. For example, the test terminal 2 detects the occurrence of a loop when the identification information of the trace correspondence switch 1 included in the received search frame response is already included in the search path list.

  Further, for example, when the test terminal 2 receives another search frame response before a predetermined time elapses from reception of the search frame response, the test frame is copied in the network and transferred in a plurality of routes. It is detected that The fact that the search frame is copied in the network and divided and transferred to a plurality of paths is hereinafter referred to as FLOOD. When the test terminal 2 receives a predetermined number of other search frame responses before a predetermined time elapses from reception of the search frame response, the test terminal 2 detects frequent occurrence of FLOOD.

  If an abnormality such as a loop or frequent occurrence of FLOOD is detected, the test terminal 2 interrupts the route search process. That is, when an abnormality is detected by receiving a search frame response, the test terminal 2 does not transmit a TP frame including a search frame transfer instruction to the trace corresponding switch 1 that is the transmission source of the search frame response.

  By holding the search frame received by the trace switch 1 and transferring the search frame by HOP-BY-HOP, the test terminal 2 can more accurately detect an abnormality such as a loop or FLOOD. . Further, when detecting an abnormality, the test terminal 2 interrupts the route search and does not receive the TP frame including the search frame transfer instruction to the trace corresponding switch 1. As a result, when an abnormality is detected in the network, the transfer of the search frame by the trace corresponding switch 1 can be stopped, and the stay of the search frame in the network can be reduced.

  (3) When the processing content for the packet in the flow table held by the SDN switch 1 is packet processing processing, the content differs between the received packet and the output packet. Examples of packet processing include address translation and encapsulation.

  In the first embodiment, when the trace correspondence switch 1 receives a TP frame including a search frame transfer instruction, the TP frame including the received search frame and the output search frame is transmitted together with the transfer of the HOLDed search frame. Is sent to the test terminal 2.

  As a result, the test terminal 2 can acquire the search frame received by the trace corresponding switch 1 existing on the route to the destination host 3 and the output search frame. By comparing these two search frames, the test terminal 2 obtains the contents of processing performed on the user packet of the route search target flow by the trace corresponding switch 1 existing on the route to the host 3 as the destination. can do.

  (4) Also, as shown in FIG. 1, when there is a trace non-corresponding switch on the path of the path search target flow, the trace non-corresponding switch does not interrupt the search path processing, It is also desirable to collect information on supported switches. The trace non-compatible switch includes a relay device of another network such as a layer 3 router.

  In the first embodiment, the test terminal 2 and the trace correspondence switch 1 transmit or transfer the TTL of the search frame as 1 by default. As a layer 3 operation, the trace incompatible switch, when receiving a search frame with a TTL of 1, discards the search frame without forwarding it based on the IP forwarding policy, and sends it to the test terminal 2 that is the transmission source. An ICMP TTL TIMEOUT message may be sent.

The test terminal 2 receives an ICMP TTL from a non-trace-compatible switch that performs layer 3 operation.
By receiving the TIMEOUT message, it is possible to acquire information such as the IP address of the switch that does not support the trace that is the transmission source of the ICMP TTL TIMEOUT message. When the test terminal 2 receives the ICMP TTL TIMEOUT message, the test terminal 2 transmits a TP frame to the trace corresponding switch 1 immediately before the trace non-compatible switch that is the transmission source of the message in the search path list. The TP frame transmitted at this time includes an instruction to transfer the HOLD search frame to a value obtained by adding TTL to 1.

  When the trace non-compliant switch that is the source of the ICMP TTL TIMEOUT message receives a probe frame having a TTL value incremented by 1, the trace non-compliant switch does not use a TTL of 1. Therefore, the probe non-trace-compatible switch performs a normal search process. Forward. As a result, even when the trace non-corresponding switch exists on the route of the route search target flow, the route search processing can be continued without being interrupted by the trace non-corresponding switch.

  In the first embodiment, there is a non-trace-compatible switch that performs Layer 3 operation on the path by performing transmission based on the conventional IP routing by transmitting or transferring the initial value of the TTL of the search frame to 1. Even in the case where there is a switch, it is possible to obtain information on the switch that does not support trace.

<Device configuration>
<Configuration of test terminal>
FIG. 2 is an example of a hardware configuration of the test terminal 2. The test terminal 2 is, for example, a general-purpose computer such as a PC (Personal Computer), a dedicated computer, a tablet terminal,
Such as a smartphone. The test terminal 2 is an example of a “test device”.

The test terminal 2 includes a CPU (Central Processing Unit) 101, a main storage device 102, an input device 103, an output device 104, an auxiliary storage device 105, and a network interface 107. These are connected to each other by a bus 109.

  The input device 103 is, for example, a keyboard, a mouse, operation buttons, a touch panel, a keypad, and the like. Data input from the input device 103 is output to the CPU 101.

The auxiliary storage device 105 stores an OS (Operating System), various programs, and data used by the CPU 101 when executing each program. The auxiliary storage device 105 is, for example, a nonvolatile memory such as an EPROM (Erasable Programmable ROM), a flash memory, or a hard disk drive. Auxiliary storage device 105
For example, the route search program 105P is stored. The route search program 105P is a route search processing program.

  The main storage device 102 is a storage device that provides the CPU 101 with a storage area and a work area for loading a program stored in the auxiliary storage device 105 and is used as a buffer. The main storage device 102 includes, for example, a semiconductor memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

  The CPU 101 executes various processes by loading the OS and various application programs held in the auxiliary storage device 105 into the main storage device 102 and executing them. The number of CPUs 101 is not limited to one, and a plurality of CPUs 101 may be provided.

  The network interface 107 is an interface for inputting / outputting information to / from the network. The network interface 107 may be an interface connected to a wired network or an interface connected to a wireless network. The network interface 107 is, for example, a wireless signal processing circuit such as a NIC (Network Interface Card) or a wireless LAN (Local Area Network). Data received by the network interface 107 is output to the CPU 101. When physically different interfaces are used for the D plane and the M plane, a plurality of network interfaces are provided.

  The output device 104 outputs the processing result of the CPU 101. The output device 104 includes a display and a printer.

  Note that the hardware configuration of the test terminal 2 shown in FIG. 2 is an example, and is not limited to the above, and components can be omitted, replaced, or added as appropriate according to the embodiment. For example, the test terminal 2 may include a portable recording medium driving device and execute a program recorded on the portable recording medium. The portable recording medium is, for example, an SD card, a miniSD card, a microSD card, a USB (Universal Serial Bus) flash memory, a CD (Compact Disc), a DVD (Digital Versatile Disc), a Blu-ray (registered trademark) Disc, or a flash. A recording medium such as a memory card.

  FIG. 3 is a diagram illustrating an example of a functional configuration of the test terminal 2. The functional configuration of the test terminal 2 shown in FIG. 3 is a functional configuration achieved by executing the route search program 105P of the CPU 101. However, the present invention is not limited to this, and the functional configuration of the test terminal 2 shown in FIG. 3 may be achieved by an electric circuit such as an FPGA (Field-Programmable Gate Array) and an ASIC (Application Specific Integrated Circuit).

The test terminal 2 includes a D-plane line interface 21, a D-plane transmission / reception control unit 22, a search frame transmission / reception control unit 23, a route search algorithm control unit 24, an HMI (Human Machine Interface) control unit 25, and a TRACE PING transmission / reception control. Part 26,
A management plane transmission / reception control unit 27 and an M plane line interface 28 are included.

  The D-plane line interface 21 and the M-plane line interface 28 are interfaces with the D-plane and M-plane networks, respectively, and correspond to the network interface 107. A packet received by the D-plane line interface 21 is output to the D-plane transmission / reception control unit 22. The packet received by the M plane line interface 28 is output to the management plane transmission / reception control unit 27. The D-plane line interface 21 only needs to be able to transmit and receive the same IP address (including a header such as VLAN) as the transmission source of the route search target flow. The IP address assigned to the M plane line interface 28 can be any IP address of the M plane.

  The D-plane transmission / reception control unit 22 receives a packet input from the D-plane line interface 21, and determines the type of the input packet. Packets received via the D-plane line interface 21 include, for example, a search frame response whose destination IP address belongs to the D plane, a TP response frame whose destination IP address belongs to the D plane, an ICMP TTL TIMEOUT message, and a TCP SYN ACK packet. .

  If the received packet is a search frame response, the D-plane transmission / reception control unit 22 outputs the search frame response to the search frame transmission / reception control unit 23. When the received packet is a TP response frame, the D-plane transmission / reception control unit 22 outputs the TP response frame to the TP transmission / reception control unit 26. If the received packet is neither a search frame response nor a TP response frame, the D-plane transmission / reception control unit 22 outputs the received packet to the route search algorithm control unit 24.

  The D-plane transmission / reception control unit 22 transmits a packet to the D-plane network. Examples of the packet transmitted by the D-plane transmission / reception control unit 22 include a search frame and a TP frame whose destination IP address belongs to the D-plane.

  The management plane transmission / reception control unit 27 transmits a packet to the M-plane network. The packet transmitted by the management plane transmission / reception control unit 27 includes, for example, a TP frame whose destination IP address belongs to the M plane. The management plane transmission / reception control unit 27 receives an input of the TP frame from the TP transmission / reception control unit 26 and outputs the TP frame to the M plane line interface 28.

  Further, the management plane transmission / reception control unit 27 receives a packet input from the M plane line interface 28 and determines the type of the packet. The packets that the management plane transmission / reception control unit 27 receives input include, for example, a search frame response whose destination IP address belongs to the M plane and a TP response frame whose destination IP address belongs to the M plane.

  When the received packet is a search frame response, the management plane transmission / reception control unit 27 outputs the search frame response to the search frame transmission / reception control unit 23. When the received packet is a TP response frame, the management plane transmission / reception control unit 27 outputs the TP response frame to the TP transmission / reception control unit 26.

The search frame transmission / reception control unit 23 generates a search frame in accordance with an instruction from the route search algorithm control unit 24, and outputs the generated search frame to the D-plane transmission / reception control unit 22. The generated search frame is a TCP SYN packet, has the same packet identification information as the route search target flow, and has a TTL value of 1. Details of the search frame will be described later.

  The search frame transmission / reception control unit 23 receives a search frame response input from the D plane transmission / reception control unit 22 or the management plane transmission / reception control unit 27, extracts predetermined information from the search frame response, and extracts a route search algorithm control unit. 24. The predetermined information extracted from the search frame response includes, for example, a transmission source IP address and a search frame HOLD ID. The HOLD ID of the search frame is identification information given to the search frame by the trace correspondence switch 1. Details of the search frame response will be described later. The search frame transmission / reception control unit 23 is an example of a “transmission unit” of the “test apparatus”.

  The TP transmission / reception control unit 26 generates a TP frame according to an instruction from the route search algorithm control unit 24, and sends the generated search frame to the D plane transmission / reception control unit 22 or the management plane transmission / reception control unit 27 according to the destination IP address. Output. The generated TP frame is, for example, an ICMP ECHO REQUEST message. Details of the TP frame will be described later.

  Further, the TP transmission / reception control unit 26 receives an input of a TP response frame from the D plane transmission / reception control unit 22 or the management plane transmission / reception control unit 27 according to the destination IP address. The TP transmission / reception control unit 26 extracts predetermined information from the TP response frame and outputs it to the route search algorithm control unit 24. The predetermined information extracted from the TP response frame includes, for example, the reception and output port number of the search frame, the content of the received search frame, the content of the output search frame, and the like. Details of the TP response frame will be described later.

  The HMI control unit 25 is an interface with the operator of the test terminal 2, and receives input of test parameters from the input device 103 and controls display of the acquired path information on the output device 104. The test parameter includes, for example, packet identification information of the route search target flow. When a route search start instruction is input from the operator, the HMI control unit 25 outputs a route search start instruction, test parameters, and the like to the route search algorithm control unit 24.

  The route search algorithm control unit 24 controls the TRACE PING based on the search frame transmission and the search frame response, and searches the route to the destination device of the route search target flow. In addition, the route search algorithm control unit 24 receives input of information extracted from the search frame response from the search frame transmission / reception control unit 23 and information extracted from the TP response frame from the TP transmission / reception control unit 26. The TP transmission / reception control unit 26 is an example of a “control frame transmission unit”.

  The route search algorithm control unit 24 records information extracted from the search frame response and the TP response frame in the search route list, and acquires route information of the route search target flow. Further, the route search algorithm control unit 24 outputs information recorded in the search route list to the HMI control unit 25 based on, for example, a result output instruction from the operator. Details of the processing of the route search algorithm control unit 24 will be described later. The route search algorithm control unit 24 is an example of a “control unit” of the “test apparatus”.

<Configuration of trace compatible switch>
The SDN switch 1 is a virtual machine (VM), and as an entity, for example, a dedicated computer such as a server or a general-purpose computer such as a PC (personal computer). The hardware configuration of the trace switch 1 is almost the same as that of the test terminal 2, and includes at least a CPU, a main storage device, an auxiliary storage device, and a plurality of network interfaces. Since the details of these hardware components are as described above, description thereof will be omitted.

  The auxiliary storage device of the trace correspondence switch 1 stores a trace correspondence SDN switch program. The trace-compatible SDN switch program is a program for realizing the trace-compatible switch 1 on a computer as a virtual machine. The trace correspondence switch 1 is an example of a “relay device”.

  FIG. 4 is a diagram illustrating an example of a functional configuration of the trace correspondence switch 1. The functional configuration of the trace 1 shown in FIG. 4 is a functional configuration achieved by executing the trace compatible program of the CPU of the trace compatible switch.

  The trace-compatible switch 1 includes a D-plane line interface 11A, an M-plane line interface 11B, a frame reception control unit 12A, a frame transmission control unit 12B, a management plane transmission / reception control unit 12C, a reception search frame HOLD control unit 13, and a search function. A frame response control unit 14, an SDN-compatible switch control unit 15, a next search frame HOLD control unit 16, a next search frame output control unit 17, and a TRACE PING transmission / reception control unit 18 are included.

  The D-plane line interface 11A and the M-plane line interface 11B are interfaces with the D-plane and M-plane networks, respectively, and correspond to the network interface 107.

  The frame reception control unit 12A receives a packet input from the D-plane line interface 11A and determines the packet type. Examples of the packet that the frame reception control unit 12A receives input include a search frame and a TP frame whose destination IP address belongs to the D plane.

  If the received packet is a search frame, the frame reception control unit 12A outputs the search frame to the reception search frame HOLD control unit 13. If the received packet is a TP frame, the frame reception control unit 12A outputs the received packet to the SDN-compatible switch control unit 15. If the received packet is neither a search frame nor a TP frame, the frame reception control unit 12A outputs the received packet to the SDN-compatible switch control unit 15.

  The reception search frame HOLD control unit 13 receives an input of a search frame from the frame reception control unit 12A. The received search frame HOLD control unit 13 assigns a HOLD ID to the received search frame and holds it in the buffer (HOLD). When receiving an input of a TP frame transfer instruction from the TP transmission / reception control unit 18, the reception search frame HOLD control unit 13 reads the search frame from the buffer and outputs it to the SDN-compatible switch control unit 15.

  When no exploration frame transfer instruction based on the TP frame is input even after a predetermined time has elapsed, and when an exploration frame discard instruction based on the TP frame is input, the reception exploration frame HOLD control unit 13 is HOLDing. Discard the probe frame. The predetermined time is, for example, 1 to 10 seconds. The reception search frame HOLD control unit 13 is an example of a “storage unit”. The buffer is an example of a “storage unit”.

When the search frame response is held by the received search frame HOLD control unit 13, the search frame response control unit 14 generates a search frame response from the HOLDed search frame. The search frame stores the IP address of the test terminal 2 to which the search frame response is returned (details will be described later). The search frame response control unit 14 extracts an IP address as a return destination of the search frame response from the search frame.

  The search frame response control unit 14 determines whether the destination IP address of the extracted search frame response belongs to the M plane or the D plane. This determination is made based on the network address of the extracted IP address.

  The SDN switch 1 has a virtual port to identify itself. The virtual port is referred to as a local port. For example, an address belonging to the D plane is assigned to the local port. If the destination IP address of the search frame response is an address belonging to the D plane, the search frame response control unit 14 sets the source IP address of the search frame response as the IP address of its own local port and the frame transmission control unit 12B. Send through. When the source IP address of the search frame response is the IP address of the local port, the destination IP address of the TP frame received from the test terminal 2 is the local port, and the TP frame is the D-plane line interface 11A. Are received via the frame reception control unit 12A.

  When the destination IP address of the search frame response is an address belonging to the M plane, the search frame response control unit 14 sets the source IP address of the search frame response to the interface connected to the M plane. Use IP address. In this case, the search frame response control unit 14 transmits the search frame response through the management plane transmission / reception control unit 12C. The search frame response control unit 14 is an example of a “transmission unit” of the “relay device”.

  The SDN-compatible switch control unit 15 performs transfer processing and predetermined processing on the received packet. The SDN-compatible switch control unit 15 includes a flow table 151 and a frame processing control unit 152.

  The flow table 151 includes a correspondence between a condition including packet identification information and processing contents for a packet that matches the condition. The processing content for the packet includes, for example, transfer from the output port, rewriting of the field value in the header, encapsulation, packet discard, storage in a queue, and the like. An entry of the flow table 151 whose processing content for a packet is packet transfer is an example of “route information”.

  The SDN-compatible switch control unit 15 receives a packet input from the frame reception control unit 12A. Further, the SDN-compatible switch control unit 15 receives an input of a search frame from the reception search frame HOLD control unit 13. The SDN-compatible switch control unit 15 determines the output port and processing of the packet or search frame based on the packet identification information of the input packet or search frame and the flow table 151. Note that the packet that receives input from the frame reception control unit 12A includes a TP frame having the IP address of the local port as the destination IP address.

  The frame processing control unit 152 performs packet processing processing such as rewriting and encapsulation of field values in the packet header. The frame processing control unit 152 performs processing on the packet according to the flow table 151.

The SDN-compatible switch control unit 15 outputs a search frame that has been subjected to predetermined processing according to the flow table 151 to the next search frame HOLD control unit 16. Hereinafter, a search frame that has undergone predetermined processing according to the flow table 151 is referred to as a next search frame. The SDN-compatible switch control unit 15 outputs a packet other than the search frame that has undergone predetermined processing according to the flow table 151 to the frame transmission control unit 12B. However, the SDN-compatible switch control unit 15 outputs the TP frame addressed to the local port to the TP transmission / reception control unit 18.

  For packets that do not have an entry that matches the flow table 151, the SDN-compatible switch control unit 15 performs processing according to Open Flow, such as inquiring of the SDN controller.

  The next search frame HOLD control unit 16 receives an input of the next search frame from the SDN correspondence switch control unit 15 and holds the next search frame in the buffer (HOLD). The next search frame HOLD control unit 16 outputs the search frame in the buffer to the next search frame output control unit 17.

  The next search frame HOLD control unit 16 discards the search frame in the buffer when an instruction to discard the search frame using the TP frame is input from the TP transmission / reception control unit 18.

  The next search frame output control unit 17 receives an input of a search frame transfer instruction using a TP frame from the TP transmission / reception control unit 18 and an input of the next search frame from the next search frame HOLD control unit 16. The next search frame output control unit 17 again shapes the next search frame into the shape of the search frame, and outputs the search frame to the frame transmission control unit 12B. This is because the next search frame may not maintain the search frame format (described later) due to the processing by the frame processing control unit 152. When the TTL value is specified in the search frame transfer instruction, the next search frame output control unit 17 rewrites the TTL of the search frame with the specified value. The next search frame output control unit 17 is an example of a “transfer unit”.

  The frame transmission control unit 12B receives packet input from the SDN-compatible switch control unit 15 and the next search frame output control unit 17, and outputs the packet to the D-plane line interface 11A. The packet transmitted by the frame transmission control unit 12B to the D-plane line interface 11A includes, for example, a search frame, a search frame response whose destination IP address is the D plane, and a TP response frame whose destination IP address is the D plane.

  The management plane transmission / reception control unit 12C performs transmission / reception control of packets with the M plane. The management plane transmission / reception control unit 12C receives a packet input from the M-plane line interface 11B and determines the type of the packet. The packet that the management plane transmission / reception control unit 12C receives input from the M plane line interface 11B includes, for example, a TP frame whose destination IP address belongs to the M plane. When the received packet is a TP frame, the management plane transmission / reception control unit 12C outputs the TP frame to the TP transmission / reception control unit 18.

  Also, the management plane transmission / reception control unit 12C receives packet input from the search frame response control unit 14 and the TP transmission / reception control unit 18, and sends the packet to the M plane line interface 11B. Examples of the packet sent to the M plane line interface 11B by the management plane transmission / reception control unit 12C include a search frame response whose destination IP address belongs to the M plane and a TP response frame whose destination IP address belongs to the M plane.

The TP transmission / reception control unit 18 receives a TP frame from the test terminal 2 and instructs the transfer or discard of the search frame according to the TP frame. When the TP frame is received via the D plane, the TP frame is input to the TP transmission / reception control unit 18 through the D plane line interface 11A and the SDN-compatible switch control unit 15. When the TP frame is accepted via the M plane, the TP frame is input to the TP transmission / reception control unit 18 through the M plane line interface 11B and the management plane transmission / reception control unit 12C.

  When receiving the TP frame, the TP transmission / reception control unit 18 extracts an operation instruction included in the TP frame. In the first embodiment, the operation instruction included in the TP frame is transfer or discard of the TP frame.

  When a search frame transfer instruction is included in the TP frame, the TP transmission / reception control unit 18 outputs a search frame transfer instruction to the reception search frame HOLD control unit 13 and the next search frame output control unit 17. Further, the TP transmission / reception control unit 18 reads the search frame held in each of the reception search frame HOLD control unit 13 and the next search frame output control unit 17, stores it in the TP response frame, and stores the TP response frame. Send. The TP response frame is transmitted via the D plane or the M plane according to the transmission source IP address of the TP frame.

  When the TP frame includes a TTL value designation in addition to the search frame transfer instruction, the TP transmission / reception control unit 18 designates the TTL value together with the search frame transfer instruction in the next search frame. Output to the output control unit 17.

  When the exploration frame discard instruction is included in the TP frame, the TP transmission / reception control unit 18 outputs the exploration frame discard instruction to the reception exploration frame HOLD control unit 13 and the next exploration frame HOLD control unit 16. In response to this instruction, the received search frame HOLD control unit 13 and the next search frame HOLD control unit 16 discard the HOLD search frame. The TP transmission / reception control unit 18 is an example of a “response transmission unit”.

<Frame format>
FIG. 5 is an example of a frame format of the search frame. The search frame has packet identification information of the route search target flow, and is a packet transmitted from the test terminal to the host 3 that is the destination of the route search target flow. Layer 2 destination and source MAC address, VLAN ID, layer 3 destination and source IP address, protocol number, TCP destination and source port number, etc. of the search frame are the same values as the user packet of the route search target flow Set to

  A TCP SYN packet is used for the search frame. Since the search frame is a TCP SYN packet, when the search frame arrives at the destination host 3, the destination host 3 returns a TCP SYN ACK packet as a response to the search frame, and confirms communication. Can do.

  The search frame has the same packet identification information as the user packet of the route search target flow. Therefore, by storing a value for identifying the search frame in, for example, a field that is not used in the SDN network, the search frame and the user packet of the route search target flow are identified.

  First, the TTL value of the search frame is set to 1 as an initial value. Next, by using the IP ID field (16 bits) in the IP header, the TCP SEQ field (32 bits) in the TCP header, and the MSS option field (16 bits) in the TCP option header, An IP address, a search frame identification value, and a hash value are stored.

As the return IP address of the search frame response, an IP address belonging to the D plane assigned to the D plane line interface 21 of the test terminal 2 or an IP address belonging to the M plane assigned to the M plane line interface 28 is stored. Whether the search frame response is received via the D plane or the M plane is determined by the presence of the M plane and an instruction from the operator of the test terminal 2.

  The search frame identification value is a value for identifying the search frame, and for example, a huge MSS value such as 64000 that does not exist in an actual network is used. The hash value is a value acquired by hash calculation from the return IP address of the search frame response and the search frame identification value.

IP address of return address of search frame response, IP of search frame identification value, hash value
The storage method in the ID field, TCP SEQ field, and MSS option field is not limited.

  The search frame is generated by the search route algorithm control unit 24 of the test terminal 2 and transmitted via the D plane. This is because the destination IP address of the search frame is the IP address of the host 3 that is the destination of the route search target flow. When the trace correspondence switch 1 receives the search frame, the frame reception control unit 12A of the trace correspondence switch 1 determines whether it is a search frame.

  First, the frame reception control unit 12A of the trace switch 1 determines whether or not the TTL value of the received packet is 1. When the TTL value of the received packet is 1, the frame reception control unit 12A determines the hash value from the return IP address and search frame identification value of the search frame response in the IP ID field, TCP SEQ field, and MSS option field. Calculate When the calculated hash value matches the hash values in the IP ID field, TCP SEQ field, and MSS option field, the frame reception control unit 12A determines that the received packet is a search frame.

  Thus, since the trace corresponding switch 1 only has to calculate the hash value when the TTL value of the received packet is 1 instead of all the received packets, the overhead associated with frame transfer can be kept low. In addition, since the TTL value of the search frame is 1, even if a user frame with a TTL value of 1 is misidentified as a search frame and discarded, the user frame originally has a TTL of 1, so user communication is not affected. It doesn't reach. Further, by using a huge value for the search frame identification value and embedding a hash value in the IP ID field, TCP SEQ field, and MSS option field, the misidentification of the search frame can be further reduced.

FIG. 6 shows an example of a frame format of the search frame response. The search frame response is a frame transmitted from the trace corresponding switch 1 to the test terminal 2 as a response to the search frame. In the first embodiment, the ICMP TIME EXCEEDED is used as the search frame response.
A message is used.

  Since the TTL value of the search frame is 1 (see FIG. 5), the TTL value of the search frame may be 0 in a normal L3SW (router) that has received the search frame. In IP forwarding, there is a mechanism in which a device that has received a packet with a TTL value of 0 sends an ICMP TIME EXCEEDED message to the transmission source device of the packet to notify that no further transfer is possible. In the first embodiment, since a conventional IP forwarding mechanism is also used, an ICMP TIME EXCEEDED message is used for the search frame. However, the present invention is not limited to this, and a new frame format may be defined as the search frame response.

  As the destination IP address of the search frame response, the return IP address of the search frame response extracted from the search frame is used. If the extracted reply destination IP address of the search frame response is an address belonging to the M plane, the source IP address of the search frame response belongs to the M plane assigned to the M plane line interface 11B of the trace corresponding switch 1. An IP address is used. If the extracted reply destination IP address of the search frame response is an address belonging to the D plane, the source IP address of the search frame response belongs to the D plane assigned to the local port of the trace corresponding switch 1. An IP address is used.

  In the ICMP data portion of the ICMP TIME EXCEEDED message, normally, the header information of the original IP packet that has timed out with a TTL value of 1 is stored. The first 4 bits of the header information of the IP packet are a version field for storing the IP version, and normally 0x4 indicating IPv4 or 0x6 indicating IPv6 is stored.

  When an ICMP TIME EXCEEDED message is used as a search frame response, the ICMP data portion stores the value of the first 4 bits of the search frame header information changed to a search frame response identification value other than 0x4 and 0x6. Is done. Furthermore, the HOLD ID of the search frame is also stored in the ICMP data portion of the search frame response. The HOLD ID of the search frame is an identification number of the search frame in the trace corresponding switch 1 that is given when the search frame is HOLDed by the reception search frame HOLD control unit 13 of the trace compatible switch 1.

  A specific value is set as an identifier of the search frame response in the IP ID field in the IP header of the search frame response, and the search frame response is identified together with the value of the first 4 bits of the header information in the ICMP data. Also good.

  The search frame response is generated by the search frame response control unit 14 of the trace switch 1 and is transmitted to the test terminal 2 via the D plane or the M plane. The D plane transmission / reception control unit 22 or the management plane transmission / reception control unit 27 of the test terminal 2 determines the search frame response by confirming the first 4 bits of the ICMP data portion of the search frame response and the search frame response identification value.

  Next, the search frame transmission / reception control unit 23 of the test terminal 2 extracts the transmission source IP address (IP address of the trace corresponding switch 1) and the HOLD ID from the search frame response, and outputs them to the route search algorithm control unit 24. The route search algorithm control unit 24 records the source IP address of the search frame response in the search route list.

  Next, the TP transmission / reception control unit 26 of the test terminal 2 creates a TP frame with the source IP address of the search frame response (the IP address of the trace corresponding switch 1) as the destination IP address. Further, the TP transmission / reception control unit 26 can instruct transfer or discard of the specified HOLD ID search frame by storing the HOLD ID included in the search frame response in the TP frame.

  FIG. 7 is an example of a frame format of the TRACE PING frame. When the test terminal 2 receives the search frame response, the TP frame is a frame transmitted to the trace corresponding switch 1 that is the transmission source of the search frame response. In the first embodiment, an ICMP ECHO REQUEST message is used for the TP frame. However, the present invention is not limited to this. For example, a new frame format may be defined as the TP frame.

  As the transmission source IP address of the TP frame, the IP address of the test terminal 2 notified by the test terminal 2 as the reply destination IP address of the search frame response in the search frame is set. The destination IP address of the TP frame is the source IP address of the search frame response, and the IP address of the trace corresponding switch 1 is set.

  A TRACE PING identification data string for identifying the TP frame is set at the head of the ICMP data portion of the TP frame. The TRACE PING identification data string is, for example, a character string such as ### TRACE-PING-REQUEST ###.

  Note that a specific value may be set as an identifier of the TP frame in the IP ID field in the IP header of the TP frame to make it more difficult to be mistaken.

  The ICMP data portion of the TP frame includes an operation instruction field, a search frame TTL value field, and a search frame HOLD ID field.

In the operation instruction field, either a search frame transfer instruction or a search frame discard instruction is set. In the field of the TTL value of the search frame, a TTL value used for transferring the search frame that is HOLD in the trace correspondence switch 1 is set. The HOLD ID field of the search frame contains a HOLD of the search frame that is the target of the operation instruction.
An ID is set. The HOLD ID of the search frame is a value acquired from the search frame response.

  The TP frame is generated by the TP transmission / reception control unit 26 of the test terminal 2 and transmitted to the trace corresponding switch 1 via the D plane or the M plane. In the trace compatible switch 1, the frame reception control unit 12A or the management plane transmission / reception control unit 12C identifies the TP frame by confirming the TRACE PING identification data string in the ICMP data part of the TP frame.

  The TP transmission / reception control unit 18 of the trace switch 1 extracts an operation instruction, a TTL value of the search frame, and a HOLD ID of the search frame from the TP frame, and performs processing (transfer or discard of the search frame) based on the operation instruction. . When the processing is completed, the TP transmission / reception control unit 18 generates a TP response frame and transmits it to the test terminal 2.

  FIG. 8 is an example of a frame format of the TRACE PING response frame. The TP response frame is transmitted from the trace corresponding switch 1 to the test terminal 2 as a response to the TP frame. An ICMP ECHO REPLY message is used for the TP response frame. However, the present invention is not limited to this. For example, when a new frame format is defined in the TP frame, a new frame format may be defined as the TP response frame.

  The IP address of the trace switch 1 itself set as the destination IP address of the TP frame is set as the source IP address of the TP response frame. The destination IP address of the TP frame is also the IP address used as the source IP address by the trace corresponding switch 1 in the search frame response.

  As the destination IP address of the TP response frame, the IP address of the test terminal 2 set as the source IP address of the TP frame is set. The IP address set as the transmission source IP address of the TP frame is also the return IP address of the search frame response notified by the search frame.

  A TP response identification data string for identifying a TP response frame is set at the head of the ICMP data portion of the TP response frame. The TP response identification data string is, for example, a character string such as ### TRACE-PING-REPLY ###. Note that a specific value may be set as an identifier of the TP response frame in the IP ID field in the IP header of the TP response frame to make it more difficult to be mistaken.

  The ICMP data portion of the TP response frame includes, for example, a processing result field and a HOLD ID field of the search frame. The processing result field includes the result of the processing indicated by the TP frame. Values included in the processing result field are, for example, normal termination, error occurrence, error code, and the like.

  The HOLD ID of the search frame is the HOLD ID of the search frame to be processed, and the HOLD ID specified in the TP frame is set.

  If the TP frame instruction is a search frame transfer instruction, the ICMP data portion of the TP response frame includes a search frame reception port number, a received search frame content, a next search frame output port number, The contents of the next search frame are stored.

  The search frame is a TCP SYN packet (see FIG. 5), does not have a data portion, and has a short frame length. For example, the search frame is about 70 bytes. On the other hand, the TP response frame can store data up to 1500 bytes. Therefore, the TP response frame can store both the received search frame and the next search frame in the ICMP data portion.

  The TP response frame is generated by the TP transmission / reception control unit 18 of the trace switch 1 and transmitted to the test terminal 2 via the D plane or the M plane. The D plane transmission / reception control unit 22 or the management plane transmission / reception control unit 27 of the test terminal 2 determines the TP response frame by confirming the TP response identification data string at the head of the ICMP data portion of the TP response frame.

  The TP transmission / reception control unit 26 of the test terminal 2 extracts the processing result from the TP response frame and outputs it to the route search algorithm control unit 24. When the TP response frame includes the reception port number of the search frame, the content of the received search frame, the output port of the next search frame, and the content of the next search frame, these pieces of information are stored in the route search algorithm control unit 24. Is output.

  When the route search algorithm control unit 24 of the test terminal 2 receives the search frame reception port number, the received search frame content, the next search frame output port, and the next search frame content, Recorded as information on the corresponding trace-compatible switch recorded in the search path list.

  When transmitting a TP frame including a search frame transfer instruction, the test terminal 2 can acquire both the received search frame and the next search frame by the TP response frame. For example, the exploration frame received by the test terminal 2 and the transferred exploration frame and contents are output to the display device, and the operator detects what processing has been performed on the exploration frame by comparing them. be able to. Alternatively, the test terminal 2 may compare both the received search frame and the next search frame. Thus, since the search frame has the same packet identification information as the route search target flow, it is possible to detect what processing is performed on the packet of the route search target flow by the trace correspondence switch 1. .

<Exploration route list>
FIG. 9 is an example of a search route list used by the test terminal 2 in route search. The search route list is created in the storage area of the main storage device 102 of the test terminal 2. For example, the search route list is recorded in a hierarchical structure with the test terminal 2 itself as a root. However, the test terminal 2 may not be recorded in the search route list. In the search route list, for example, the current hierarchy is indicated by a pointer.

  The test terminal 2 transmits the search frame or the TP frame including the search frame transfer instruction, and the identification information of the source device of the search frame response or normal ICMP TIME EXCEEEDE message received within a predetermined time is indicated by the pointer. Recorded in the hierarchy shown. For example, when a plurality of search frame responses are received within the predetermined time, the identification information of the transmission source device of the plurality of search frame responses is recorded in the same hierarchy indicated by the pointer.

  When a TP frame including a search frame transfer instruction is transmitted, the pointer advances to the next layer. When a TCP SYN ACK packet is received from the destination host 3 of the flow to be searched for a route, the route search process ends and the update of the route search list also ends.

  In the process shown in FIG. 9, for convenience, SW # 1, SW # 2,. . . In the actual search route list, for example, each is identified by an IP address.

  In the example shown in FIG. 9, SW # 40, SW # 41, and SW # 42 are recorded at the fifth level of the search path list, and the search frame is flooded from SW # 30 at the fourth level for some reason. Is detected.

  Also, for example, when the pointer indicates the fourth stage and the test terminal receives a search frame response from SW # 20, since SW # 20 is recorded in the second stage, a loop occurs. Is detected.

  FIG. 10 is an example of device entry information recorded in the search route list. Each device recorded in the search route list holds entry information as shown in FIG. The entry information is held in the storage area of the main storage device 102 of the test terminal 2.

  The device entry information includes, for example, a switch type, a switch IP address, an input port number, an input search frame, an output port number, an output search frame, and a pointer item to the next search entry item.

  The switch type item stores information indicating whether the device is a trace compatible switch, a trace non-compatible switch, or a destination host of a path search target flow. When the device information is recorded in the search path list by receiving the search frame response, the device is recorded as a trace corresponding switch. When the device information is recorded in the search path list by receiving ICMP TIME EXCEEDED, the device is recorded as a trace non-corresponding switch. When the device information is recorded in the searched route list by receiving the TCP SYN ACK packet, the device is recorded as the destination host of the route search target flow.

  The switch IP address item stores the IP address of the device. The IP address of the device is acquired from the source IP address of the search frame response, ICMP TIME EXCEEDED, or TCP SYN ACK packet.

  The input port number item stores the port number at which the corresponding trace-compatible switch 1 has received the search frame. In the item of the input search frame, the contents of the search frame received by the corresponding trace corresponding switch 1 are stored. The output port number item stores the port number at which the corresponding trace switch 1 outputs the search frame. The contents of the search frame output by the corresponding trace corresponding switch 1 are stored in the item of the output search frame.

  The items of the input port number, the input search frame, the output port number, and the output search frame are valid when the corresponding device is the trace corresponding switch 1. The values of the input port number, input search frame, output port number, and output search frame items are stored based on the TP response frame from the corresponding trace corresponding switch 1.

  In the item of the pointer to the next search entry item, the port number that received the search frame of the next layer device is stored. In the item of the pointer to the next search entry item, for example, the value is stored together with the value stored in the item of the input port number of the entry information of the device recorded in the next hierarchy. The number of items of the pointer to the next search entry item can be held by the number of devices in the next hierarchy.

  For example, when a route search result output instruction is input from the operator of the test terminal 2 through the HMI control unit 25, the route search algorithm control unit 24 displays the search route list shown in FIG. 9 or FIG. The entry information of each device is output from the output device 105. Alternatively, the test terminal 2 may include an application for analyzing a route search list and entry information, and output an analysis result by the application.

<Process flow>
<Processing flow of test terminal>
FIG. 11 is an example of a flowchart of route search processing of the route search algorithm control unit 24 of the test terminal 2. The process shown in FIG. 11 is started when, for example, a route search process start instruction is input from the operator through the HMI control unit 25, the path search program 105P is started. The subsequent processing of the flowchart of the test terminal 2 will be described with the route search algorithm control unit 24 as a main body, but the substance of the process execution is the CPU 101 of the test terminal 2 that executes the route search program 105P.

  In OP1, the route search algorithm control unit 24 instructs the search frame transmission / reception control unit 23 to generate and transmit a search frame addressed to the host 3 that is the destination of the route search target flow. The search frame is generated based on parameters input by an operator, for example. The parameters of the search frame are, for example, packet identification information (destination and transmission source IP address, destination and transmission source port number, protocol number) of the route search target flow, and an IP address of a response to the search frame response.

  If the route search algorithm control unit 24 receives an input of a normal ICMP TIME EXCEEDED message from the D-plane transmission / reception control unit 22 after transmitting the search frame, the process proceeds to OP2. When the route search algorithm control unit 24 receives input of search frame response information from the search frame transmission / reception control unit 23, the process proceeds to OP4. When the route search algorithm control unit 24 receives an input of a TCP SYN ACK packet from the D-plane transmission / reception control unit 22, the process proceeds to OP5. If the route search algorithm control unit 24 times out waiting for a search frame response, the process proceeds to OP7.

In OP2, the route search algorithm control unit 24 performs normal ICMP TIME EXC.
Since the input of the EEDED message is accepted, the transmission source of the message is recorded in the search path list as a trace non-corresponding switch. The fact that a normal ICMP TIME EXCEEDED message is received means that the source device of the message is a non-trace-compatible switch that recognizes the probe frame as an error without recognizing the probe frame as a probe frame due to a timeout of the TTL value. It is for showing. Next, the process proceeds to OP3.

  In OP3, the route search algorithm control unit 24 instructs the search frame transmission / reception control unit 23 to retransmit the search frame set to a value obtained by adding 1 to the TTL value. In response to an instruction from the route search algorithm control unit 24, the search frame transmission / reception control unit 23 transmits a search frame having a TTL value incremented by one. Next, the process returns to point A.

  In OP4, the route search algorithm control unit 24 receives an input of search frame response information, and performs search frame response reception processing. Details of the search frame response reception processing will be described later. When the search frame response reception process ends, the process shown in FIG. 11 ends.

  In OP5, since the route search algorithm control unit 24 receives the input of the TCP SYN ACK packet, the route search algorithm control unit 24 records the packet transmission source device in the search route list as the search target host. The TCP SYN ACK packet is received because the search frame is a TCP SYN packet, indicating that the transmission source device of the TCP SYN ACK packet is the destination host 3. Next, the process proceeds to OP6.

  In OP6, the route search algorithm control unit 24 transmits the TCP RST packet to the host 3 that is the transmission source of the TCP SYN ACK packet through the D-plane transmission / reception control unit 22, and disconnects the TCP session. This is because the TCP session is established between the test terminal 2 and the host 3 by the reception of the TCP SYN ACK packet by the test terminal 2, but the route search is completed and the TCP session is unnecessary. . Thereafter, the process shown in FIG. 11 ends.

  In OP7, the route search algorithm control unit 24 transmits the search frame, and has not received any of the search frame response, ICMP TIME EXCEEDED message, or TCP SYN ACK packet. Judgment is impossible. The time-out time is a value between 3 and 60 seconds, for example. Thereafter, the process shown in FIG. 11 ends.

  FIG. 12 is an example of a flowchart of the search frame response reception process in FIG. The search frame response reception process is a process when the test terminal 2 receives a search frame response. The process illustrated in FIG. 12 is started when the route search algorithm control unit 24 receives input of search frame response information.

  In OP11, the route search algorithm control unit 24 determines whether or not the information of the trace corresponding switch 1 that is the transmission source of the search frame response is already recorded in the search route list. When the information of the trace corresponding switch 1 that is the transmission source of the search frame response is already recorded in the search path list (OP11: YES), the process proceeds to OP12. When the information of the trace corresponding switch 1 that is the transmission source of the search frame response is not recorded in the search path list (OP11: NO), the process proceeds to OP13.

In OP12, since the information of the trace corresponding switch 1 that is the transmission source of the search frame response is already recorded in the search path list, the path search algorithm control unit 24 detects a loop and ends the path search. Further, the TP transmission / reception control unit 26 transmits a TP frame including a search frame discard instruction to the trace corresponding switch 1 that is a transmission source of the search frame response, and receives the TP response frame from the trace corresponding switch 1. Thereafter, the processing shown in FIG. 12 ends, and the route search processing ends.

  The processing after OP13 is processing when the information of the trace corresponding switch 1 that is the transmission source of the search frame response is not recorded in the search path list. In OP13, the route search algorithm control unit 24 records the search frame response transmission source device as a trace corresponding switch in the search route list. Next, the process proceeds to OP14.

  In OP14, the route search algorithm control unit 24 waits for a predetermined time. The predetermined time is, for example, 1 to 10 seconds. When the route search algorithm control unit 24 receives input of other search frame response information from the search frame transmission / reception control unit 23 after the predetermined time has elapsed, the process proceeds to OP15. If the route search algorithm control unit 24 does not accept input of any search frame response information after the predetermined time has elapsed, the process proceeds to OP18.

  In OP15, after transmitting a search frame or a TP frame including a search frame transfer instruction, the route search algorithm control unit 24 inputs another search frame response before a predetermined time elapses after the search frame response is first received. Is received, and FLOOD is detected. Next, the process proceeds to OP16.

  In OP16, the route search algorithm control unit 24 determines whether or not the FLOOD is in an allowable range, that is, whether or not the number of search frame responses that have received an input is less than a threshold value. When the number of exploration frame responses that have accepted the input is less than the threshold (OP16: YES), the route exploration algorithm control unit 24 repeatedly performs the processing from OP11 for each exploration frame response. If the number of search frame responses that accepted the input is greater than or equal to the threshold (OP16: NO), the process proceeds to OP17.

  In OP17, the route search algorithm control unit 24 determines the end of route search processing due to frequent occurrence of FLOOD in order to prevent a large amount of search frames from staying in the network. In addition, the route search algorithm control unit 24 instructs the TP transmission / reception control unit 26 to transmit a TP frame including a search frame discard instruction to each trace corresponding switch 1 that is a transmission source of the search frame response. The TP transmission / reception control unit 26 transmits a TP frame including a search frame discard instruction to each trace corresponding switch 1 that is a transmission source of the search frame response, and receives a TP response frame from each trace corresponding switch 1. Thereafter, the processing shown in FIG. 12 ends, and the route search processing ends.

  After OP18, the process is performed when a predetermined time elapses after receiving the first search frame response after receiving the first search frame response after transmitting the search frame or the TP frame including the search frame transfer instruction.

  In OP18, the route search algorithm control unit 24 transmits a TP frame including a search frame discard instruction to the trace corresponding switch 1 that is the transfer source of the search frame that triggered the transmission of the search frame response. The TP transmission / reception control unit 26 is instructed. The trace corresponding switch 1 that is the search frame transfer source that triggered the transmission of the search frame response is located in the hierarchy before the current hierarchy and closest to the current hierarchy in the search path list. This is a trace-compatible switch 1.

For example, in FIG. 9, when the current hierarchy is the fourth level and the test terminal 2 has received a search frame response from SW # 30, the target of the search frame discard instruction is S
W # 20. In FIG. 9, when the current hierarchy is the fifth level and the test terminal 2 has received a search frame response from SW # 41, the target of the search frame discard instruction is SW # 30.

  In accordance with an instruction from the route search algorithm control unit 24, the TP transmission / reception control unit 26 includes a search frame discard instruction for the trace corresponding switch 1 that is the transmission source of the search frame response that triggered the transmission of the search frame response. Send a TP frame. When a TP response frame is received from the corresponding trace corresponding switch 1, the process proceeds to OP19. If the source of the search frame that triggered the transmission of the search frame response is the test terminal 2 itself, the process of OP18 is omitted.

  In OP19, the route search algorithm control unit 24 instructs the TP transmission / reception control unit 26 to transmit a TP frame including a search frame transfer instruction to the trace corresponding switch 1 that is the transmission source of the search frame response. The TP transmission / reception control unit 26 generates and transmits a TP frame including a search frame transfer instruction to the trace correspondence SW 1 that is the transmission source of the search frame response, according to the instruction of the route search algorithm control unit 24. In addition, the route search algorithm control unit 24 starts a TP response reception process. The TP response reception process is a process related to reception of a TP response frame, and details will be described later.

  Next, the processing proceeds to point A in FIG. 11, and processing corresponding to the type of packet received thereafter is performed. However, the processing of OP3 when receiving the input of the normal ICMP TIME EXCEEDED message is different from the above. The transmission path search algorithm control unit 24 designates the TTL value added with 1 and transfers the search frame to the trace corresponding switch 1 that is the transfer source of the search frame that triggered the transmission of the normal ICMP TIME EXCEEDED message. The TP transmission / reception control unit 26 is instructed to transmit a TP frame including the instruction. The trace correspondence switch 1 that is the transfer source of the search frame that triggered the transmission of the normal ICMP TIME EXCEEDED message is a hierarchy that is earlier than the current hierarchy and closest to the current hierarchy in the search path list. The trace corresponding switch 1 is located in the position. The TP transmission / reception control unit 26 receives an instruction from the route search algorithm control unit 24, and transmits a TP frame including a specification of a TTL value to which 1 is added and a search frame transfer instruction.

  FIG. 13 is an example of a flowchart of the TRACE PING response reception process. The process shown in FIG. 13 is a process related to reception of a TP response frame for a TP frame including a search frame transfer instruction.

  After the transmission of the TP frame including the search frame transfer instruction, if the route search algorithm control unit 24 receives the input of the TP response frame before the predetermined time elapses, the process of OP21 is performed. In OP21, the route search algorithm control unit 24 extracts information from the TP response frame, and records the extracted information in the corresponding item of the entry information of the trace corresponding switch 1 that is the transmission source of the TP response frame. Thereafter, the process shown in FIG. 13 ends.

  If the route search algorithm control unit 24 does not accept the input of the TP response frame after the transmission of the TP frame including the search frame transfer instruction, the process of OP22 is performed. In OP22, the route search algorithm control unit 24 determines a search failure and ends the route search process. Thereby, the processing of FIGS. 11 and 12 is completed. Thereafter, the process shown in FIG. 13 ends.

<Processing flow of trace switch>
FIG. 14 is an example of a flowchart of D plane packet reception processing of the trace-compatible switch 1. The process illustrated in FIG. 14 is a process performed when the trace switch 1 receives a packet via the D plane. The process shown in FIG. 14 is described mainly with functional blocks, but the substance of the process execution is the CPU of the trace switch 1 that executes the trace SDN switch program.

  In OP31, the frame reception control unit 12A determines whether or not the TTL value of the received packet is 1. If the TTL value of the received packet is 1 (OP31: YES), the process proceeds to OP33. If the TTL value of the received packet is not 1 (OP31: NO), the process proceeds to OP32.

  In OP32, since the TTL value of the received packet is not 1, the frame reception control unit 12A determines that the received packet is not a search frame, and outputs the received packet to the SDN-compatible switch control unit 15. The received packet is processed according to the flow table 151 by the switch control unit 15 corresponding to the SDN, and sent to the D plane through the frame transmission control unit 12B. Thereafter, the process shown in FIG. 14 ends.

  In OP33, since the TTL value of the received packet is 1, the frame reception control unit 12A performs an analysis process as to whether or not the received packet is a search frame. Specifically, the frame reception control unit 12A calculates a hash value from the return IP address of the search frame response and the search frame identification value in the IP ID field, TCP SEQ field, and MSS option field of the received packet. When the calculated hash value matches the hash values in the IP ID field, TCP SEQ field, and MSS option field, the frame reception control unit 12A determines that the received packet is a search frame.

  If the received packet is a search frame as a result of the analysis processing (OP34: YES), the processing proceeds to OP35. If the received packet is not a search frame (OP34: NO), the process proceeds to OP32, and the received packet is processed by the SDN-compatible switch control unit 15.

  In OP35, the frame reception control unit 12A outputs the search frame to the reception search frame HOLD control unit 13. The reception search frame HOLD control unit 13 assigns a HOLD ID to the search frame, and stores the search frame and the reception port of the search frame in a buffer. Further, when the search frame is HOLD, the search frame response control unit 14 extracts the return address of the search frame response from the search frame that is HOLD. Next, the process proceeds to OP36.

  In OP36, the search frame response control unit 14 determines whether or not the return destination IP address extracted from the search frame is an IP address belonging to the M plane. When the reply destination IP address is an IP address belonging to the M plane (OP36: YES), the process proceeds to OP38. If the reply destination IP address is not an IP address belonging to the M plane, that is, if the reply destination IP address is an IP address belonging to the D plane (OP36: NO), the process proceeds to OP37.

  In OP37, since the return IP address of the search frame response belongs to the D plane, the search frame response control unit 14 generates a search frame response using the IP address assigned to the local port of the own device as the transmission source IP address. And transmitted via the D plane. Thereafter, the process shown in FIG. 14 ends.

In OP38, since the return IP address of the search frame response belongs to the M plane, the search frame response control unit 14 generates a search frame response using the IP address assigned to the M plane line interface 11B as the transmission source IP address. , And transmitted via the M plane. Thereafter, the process shown in FIG. 14 ends.

  FIG. 15 is an example of a flowchart of processing of the trace switch 1 when a packet addressed to the local port is received via the M plane. The process shown in FIG. 15 is started when the trace switch 1 receives a packet via the switch M plane or addressed to its own local port.

  In OP41, when a packet is received via the M plane, the management plane transmission / reception control unit 12C receives a packet addressed to its own local port, and when receiving a packet addressed to its own local port, the frame reception control unit 12A determines whether the received packet is a TP frame. Determine whether. If the received packet is a TP frame (OP41: YES), the TP frame is input to the TP transmission / reception control unit 18, and the process proceeds to OP43. If the received packet is not a TP frame (OP41: NO), the process proceeds to OP42.

  In OP42, since the received packet is not a TP frame, normal IP reception processing is performed by the management plane transmission / reception control unit 12C or the frame reception control unit 12A. Thereafter, the process shown in FIG. 15 ends.

  In OP43, the TP transmission / reception control unit 18 determines the operation instruction content of the TP frame. If the operation instruction content of the TP frame is a search frame transfer instruction, the process proceeds to OP44. When the operation instruction content of the TP frame is a search frame discard instruction, the process proceeds to OP50.

  OP44 to OP49 are processes when the operation instruction content of the TP frame is a search frame transfer instruction. In OP44, the TP transmission / reception control unit 18 outputs a search frame transfer instruction to the reception search frame HOLD control unit 13. In response to an instruction from the TP transmission / reception control unit 18, the received search frame HOLD control unit 13 outputs the HOLDed search frame to the SDN-compatible switch control unit 15. The search frame is a search frame having a HOLD ID designated by the TP frame transfer instruction. Next, the process proceeds to OP45.

  In OP45, the SDN-compatible switch control unit 15 processes the search frame in the same manner as the normal packet processing based on the packet identification information held in the search frame and the flow table 151. Do. By this process, the output port of the search frame is determined. When frame processing is set in the flow table 151, the frame processing control unit 152 applies predetermined frame processing to the search frame. The SDN-compatible switch control unit 15 outputs the processed search frame (next search frame) to the next search frame HOLD control unit 16. Next, the process proceeds to OP46.

  In OP46, the next search frame HOLD control unit 16 stores the next search frame and the output port in the buffer. The next search frame HOLD control unit 16 outputs the next search frame to the next search frame output control unit 17. Next, the process proceeds to OP47.

  In OP47, the next search frame output control unit 17 shapes the next search frame into a search frame format. In addition, when the TTL value is specified in the TP frame, the next search frame output control unit 17 sets the TTL value of the search frame to the value specified by the TP frame. Next, the process proceeds to OP48.

In OP48, the next search frame output control unit 17 transmits the next search frame from the output port through the frame transmission control unit 12B. Next, the process proceeds to OP49.

  In OP49, the TP transmission / reception control unit 18 acquires HOLD information from the reception search frame HOLD control unit 13 and the next search frame HOLD control unit 16, generates a TP response frame including the acquired information, and performs a test. Transmit to terminal 2. The TP response frame is transmitted through the management plane transmission / reception control unit 12C when the TP frame is received via the M plane. The TP response frame is transmitted through the frame transmission control unit 12B when the TP frame is received via the D plane. Thereafter, the process shown in FIG. 15 ends.

  OP50 and OP51 are processes when the operation instruction of the TP frame is an instruction to discard the search frame. In OP50, the TP transmission / reception control unit 18 outputs a search frame discard instruction to the reception search frame HOLD control unit 13 and the next search frame HOLD control unit 16. At this time, the HOLD ID of the search frame to be discarded designated by the TP response frame is also notified. The reception search frame HOLD control unit 13 and the next search frame HOLD control unit 16 receive a search frame discard instruction from the TP transmission / reception control unit 18 and discard the search frame of the notified HOLD ID from the buffer. Next, the process proceeds to OP51.

  In OP51, the TP transmission / reception control unit 18 generates a TP response frame including the result of the exploration frame discarding process, and transmits the TP response frame to the test terminal 2. The TP response frame is transmitted through the management plane transmission / reception control unit 12C when the TP frame is received via the M plane. The TP response frame is transmitted through the frame transmission control unit 12B when the TP frame is received via the D plane. Thereafter, the process shown in FIG. 15 ends.

<Operation example>
16A, 16B, and 16C are diagrams illustrating an example of a route search processing sequence in the network system 100 according to the first embodiment. SW # 1 to SW # 3 are assumed to be the trace corresponding switch 1. Router # 1 is a relay device in a network other than the SDN network.

  In FIG. 16A, FIG. 16B, and FIG. 16C, the route of the flow to be searched is changed to a route that passes through SW # 1, SW # 2, router # 1, and SW # 3 in this order by the SDN controller (not shown). It is assumed that it is set. Also, it is assumed that each relay device holds route information (flow table 151, routing table, etc.) according to the route. This operation example is an operation example when no abnormality such as a loop or FLOOD occurs. In FIG. 16A, FIG. 16B, and FIG. 16C, transmission / reception in the D plane is indicated by a solid line, and transmission / reception in the M plane is indicated by a broken line.

  In S1, the test terminal 2 transmits a search frame in response to an instruction to start a route search process from the operator (OP1 in FIG. 11). The return IP address of the search frame response in the search frame is assumed to be an IP address belonging to the M plane assigned to the M plane line interface 28 of the test terminal 2. The address search frame reaches SW # 1 located closest to the test terminal 2.

  In S2, since SW # 1 has received the search frame (FIG. 14, OP31: YES, OP33, OP34: YES), HOLD the search frame (FIG. 14, OP35). At this time, the HOLD ID of the search frame that is HOLD is set to 1, and the search frame with the HOLD ID of 1 is hereinafter referred to as search frame # 1.

  In S3, SW # 1 transmits an exploration frame response using the IP address of the M plane of test terminal 2 as the destination IP address and the IP address of the M plane of SW # 1 as the source IP address (FIG. 14, OP36: YES, OP37). The search frame response includes the HOLD ID of search frame # 1. It is assumed that the exploration frame response has reached the test terminal 2 before a predetermined time has elapsed since the exploration frame is transmitted from the test terminal 2.

  The test terminal 2 receives the search frame response from SW # 1, and records SW # 1, which is the transmission source of the search frame response, in the first stage of the search path list (OP13 in FIG. 12).

  In S4, the test terminal 2 transmits a TP frame including a transfer instruction for the search frame # 1 using the IP address of the M plane of SW # 1 as the destination IP address (OP19 in FIG. 12). This TP frame also includes the HOLD ID of search frame # 1.

  In S5, the TP frame reaches SW # 1 (FIG. 15, OP41: YES), and SW # 1 transfers exploration frame # 1 according to the transfer instruction of exploration frame # 1 by the TP frame (FIG. 15, OP44). ~ OP48). Search frame # 1 is transferred to SW # 2 in accordance with the packet identification information of search frame # 1 and flow table 151.

  In S6, SW # 2 has received exploration frame # 1 (FIG. 14, OP31: YES, OP33, OP34: YES), and therefore HOLD exploration frame # 1 (FIG. 14, OP35). At this time, the HOLD ID of the search frame that has been HOLD is set to 2, and the search frame with the HOLD ID of 2 is hereinafter referred to as search frame # 2.

  In S7, SW # 1 transmits a TP response frame using the IP address of the M plane of the test terminal 2 as the destination IP address (OP49 in FIG. 15). The TP response frame includes the transfer processing result (success) of the search frame # 1, the reception port of the search frame, the content of the received search frame, the output port of the search frame, and the content of the transferred search frame.

  When receiving the TP response frame from SW # 1, the test terminal 2 includes the search port receiving port and the content of the received search frame included in the TP response frame in the entry information of SW # 1 recorded in the search path list. The output port of the search frame and the contents of the transferred search frame are recorded (FIG. 13, OP21).

  In S8, SW # 2 transmits an exploration frame response with the IP address of the M plane of test terminal 2 as the destination IP address and the IP address of the M plane of SW # 2 as the source IP address (FIG. 14, OP36: YES, OP37). The search frame response includes the HOLD ID of search frame # 2. It is assumed that the exploration frame response has reached the test terminal 2 before a predetermined time has elapsed since the transmission of the TP frame of the test terminal 2 in S4.

  The test terminal 2 receives the search frame response from SW # 2, and records SW # 2, which is the transmission source of the search frame response, in the second stage of the search path list (FIG. 12, OP13).

  In S9, when the test terminal 2 receives the search response frame from SW # 2, the test terminal 2 instructs the exploration frame # 1 to be discarded to the SW # 1 that has transmitted the search frame triggered by the search response frame. A TP frame including is transmitted (FIG. 12, OP18). Since the current hierarchy of the search path list is the second level at the time of S9, SW # 1, which is the trace corresponding switch 1 closest to the current hierarchy, is the search frame that triggered the search response frame. Identified as the sender of

  In S10, SW # 1 receives the TP frame including the discard instruction for exploration frame # 1 via the M plane, and therefore discards exploration frame # 1 (OP50 in FIG. 15).

  In S11, SW # 1 transmits a TP response frame including the discard processing result (success) of exploration frame # 1 to the test terminal 2 via the M plane (FIG. 15, OP51).

  In S12, the test terminal 2 receives the search frame response from SW # 2 in S8, and transmits a TP frame including a transfer instruction for search frame # 2 with the IP address of the M plane of SW # 2 as the destination IP address. (FIG. 12, OP19).

  In S13, SW # 2 receives the TP frame including the transfer instruction for exploration frame # 2, and transfers HOLD exploration frame # 2 according to the flow table (FIG. 15, OP44 to OP48).

  In S14, SW # 2 transmits a TP response frame using the IP address of the M plane of the test terminal 2 as the destination IP address (OP49 in FIG. 15). The TP response frame includes the transfer processing result (success) of search frame # 2, the reception port of the search frame, the content of the received search frame, the output port of the search frame, and the content of the transferred search frame.

  When receiving the TP response frame from SW # 2, the test terminal 2 includes the search port reception port included in the TP response frame in the entry information of SW # 2 recorded in the search path list, and the content of the received search frame. The output port of the search frame and the contents of the transferred search frame are recorded (FIG. 13, OP21).

  In S15, the router # 1 receives the search frame transferred from the SW # 2 in S13, and the TTL of the search frame is 1, so that the router # 1 does not transfer the search frame according to the IP protocol stack. To send an ICMP TIME EXCEEDED message. Since the source IP address of the exploration frame is the D-plane IP address of the test terminal 2, the destination IP address of the ICMP TIME EXCEEDED message is the IP address of the D-plane of the test terminal 2, and the ICMP TIME EXCEEDED message is It is assumed that the test terminal 2 has been reached before a predetermined time has elapsed since the transmission of the TP frame of the test terminal 2 in S12.

  The test terminal 2 receives the ICMP TIME EXCEEDED message from the router # 1, and records it in the third stage of the search path list with the router # 1 as a non-trace switch (FIG. 11, P2).

  In S16, the test terminal # 2 designates TTL = 2 and sets the search frame # 2 to the SW # 2 that is the transfer source of the search frame that triggered the transmission of the ICMP TIME EXCEEDED message of the router # 1. A TP frame including a transfer instruction is transmitted. At the time of S16, SW # 1 is recorded in the first level, SW # 2 is recorded in the first level, and router # 1 is recorded in the third level in the search route list, and the current hierarchy (third level) is before the current level. The trace corresponding switch 1 located in the hierarchy closest to the current hierarchy is SW # 2. Accordingly, the test terminal 2 detects that SW # 2 is the search frame transfer source that triggered the transmission of the ICMP TIME EXCEEDED message of the router # 1.

  In S17, SW # 2 receives from the test terminal 2 a TP frame including the designation of TTL = 2 and the transfer instruction of search frame # 2, and sets the TTL of search frame # 2 to 2 according to the instruction of the TP frame. (FIG. 16, OP44 to OP48).

  When the search frame is transferred from SW # 2, it first reaches router # 1. Since the TTL value of the search frame is 2, router # 1 recognizes the search frame as a user packet of a flow to be searched for a route, performs normal routing, and transfers the search frame. At this time, the TTL value of the search frame is rewritten from 2 to 1 by the router # 1. Next, the exploration frame reaches SW # 3.

  In S18, SW # 3 has received the search frame (FIG. 14, OP31: YES, OP33, OP34: YES), so HOLD the search frame (FIG. 14, OP35). At this time, the HOLD ID of the search frame that is HOLD is set to 3, and the search frame with the HOLD ID of 3 is hereinafter referred to as search frame # 3.

  In S19, SW # 2 transmits a TP response frame with the IP address of the M plane of the test terminal 2 as the destination IP address (OP49 in FIG. 15). The TP response frame includes the transfer processing result (success) of search frame # 2, the reception port of the search frame, the content of the received search frame, the output port of the search frame, and the content of the transferred search frame.

  When receiving the TP response frame from SW # 2, the test terminal 2 includes the search port reception port included in the TP response frame in the entry information of SW # 2 recorded in the search path list, and the content of the received search frame. The output port of the search frame and the contents of the transferred search frame are recorded (FIG. 13, OP21). However, since the SW # 2 entry information recorded in the search path list of the test terminal 2 already stores the information of the TP response frame received in S7, it is an overwriting process.

  In S20, SW # 3 transmits an exploration frame response using the IP address of the M plane of test terminal 2 as the destination IP address and the IP address of the M plane of SW # 3 as the source IP address (FIG. 14, OP36: YES, OP37). The search frame response includes the HOLD ID of search frame # 3. It is assumed that the search frame response has reached the test terminal 2 before a predetermined time has elapsed since the transmission of the TP frame of the test terminal 2 in S16.

  The test terminal 2 receives the search frame response from SW # 3, and records SW # 3, which is the transmission source of the search frame response, in the fourth level of the search path list (OP13 in FIG. 12).

  In S21, when the test terminal 2 receives the search response frame from SW # 3, the test terminal 2 gives an instruction to discard the search frame # 2 to the SW # 2 that transmitted the search frame triggered by the search response frame. A TP frame including is transmitted (FIG. 12, OP18). Since the current hierarchy of the search route list is the fourth level at the time of S21, SW # 2, which is the trace corresponding switch 1 in the direction from the current hierarchy, is the search frame that triggered the search response frame. Identified as the sender of

  In S22, SW # 2 receives the TP frame including the discard instruction for exploration frame # 2 via the M plane, and therefore discards exploration frame # 2 (FIG. 15, OP50).

  In S23, SW # 2 transmits a TP response frame including the discard processing result (success) of search frame # 2 to test terminal 2 via the M plane (FIG. 15, OP51).

  In S24, the test terminal 2 receives the search frame response from SW # 3 in S20, and transmits the TP frame including the transfer instruction of search frame # 3 with the IP address of the M plane of SW # 3 as the destination IP address. (FIG. 12, OP19).

In S25, SW # 3 receives the TP frame including the transfer instruction of exploration frame # 3,
The HOLD search frame # 3 is transferred according to the flow table (FIG. 15, OP44 to OP48).

  In S26, SW # 3 transmits a TP response frame using the IP address of the M plane of the test terminal 2 as the destination IP address (OP49 in FIG. 15). The TP response frame includes the transfer processing result (success) of the search frame # 3, the reception port of the search frame, the content of the received search frame, the output port of the search frame, and the content of the transferred search frame.

  When receiving the TP response frame from SW # 3, the test terminal 2 includes the search port receiving port and the content of the received search frame included in the TP response frame in the entry information of SW # 3 recorded in the search path list. The output port of the search frame and the contents of the transferred search frame are recorded (FIG. 13, OP21).

  In S27, the destination host 3 receives the search frame, and transmits a TCP SYN ACK packet as a response to the search frame which is a TCP SYN packet. The TCP SYN ACK packet is transmitted using the IP address belonging to the D plane of the test terminal 2 that is the transmission source IP address of the search frame that is the TCP SYN packet as the destination IP address.

  When the test terminal 2 receives the TCP SYN ACK packet from the destination host 3, the test terminal 2 detects arrival of the destination host (OP6 in FIG. 11).

  In S28, the test terminal 2 transmits a TCP RST packet to the destination host 3 as one of the processes related to the end of the route search process (FIG. 11, OP5). The TCP RST packet is delivered to the destination host 3 by the normal transfer processing of SW # 1, SW # 2, router # 1, and SW # 3. When the TCP RST packet arrives at the destination host 3, the TCP session between the test terminal 2 and the host 3 established by exchanging the search frame and the TCP SYN ACK packet is disconnected.

  In S29, the test terminal 2 includes an instruction to discard the search frame # 3 to SW # 3, which has transferred the search frame to the destination host 3, as one of the processes related to the end of the route search process. Send a TP frame. The search frame to be discarded and the trace corresponding switch 1 to be discarded are specified from the search path list.

  In S30, SW # 3 receives the TP frame including the discard instruction for exploration frame # 3 via the M-plane, and therefore discards HOLD exploration frame # 3 (FIG. 15, OP50).

  In S31, SW # 3 transmits a TP response frame including the discard processing result (success) of exploration frame # 3 to the test terminal 2 via the M plane (FIG. 15, OP51). When the test terminal 2 receives the TP response frame, the route search process ends.

<Operational effects of the first embodiment>
By making the search frame hold the same packet identification information as the route search target flow, the search frame uses the same route information (flow table, routing table, etc.) as the user packet of the route search target flow by the relay device. Relayed. The trace corresponding switch 1 that has transferred the search frame notifies the test apparatus 2 of its own information by returning a search frame response. Therefore, the test terminal 2 can acquire information on the relay device to which the user packet of the route search target flow is actually relayed by using the search frame holding the same packet identification information as the route search target flow. it can.

  Further, the test terminal 2 records the identification information of the trace corresponding switch 1 that is the transmission source of the search frame response in the reception order in the search path list. Upon receipt of the search frame, each trace correspondence switch 1 transmits a search frame response to the test terminal 2, temporarily suspends processing related to transfer, and buffers the search frame until receiving a search frame transfer instruction from the test terminal 2. To store. The test terminal 2 records the information of the trace correspondence switch 1 in the search path list in the reception order of the search frame response, and transmits a TP frame including a search frame transfer instruction to the trace correspondence switch 1 that is the transmission source of the search frame response. . As described above, the search frame is transferred by HOP-BY-HOP, thereby guaranteeing that the order of the trace correspondence switch 1 recorded in the search path list matches the order of the actual user packets.

  In addition, for example, when an abnormality such as a loop or FLOOD in which a large amount of exploration frames may stay in the network is lurking in the network, the test terminal 2 transfers the exploration frame from the trace compatible switch 1. Before being done, the anomaly can be detected and the route search process can be stopped. As a result, it is possible to prevent a large amount of search frames from staying in the network due to a loop, FLOOD, or the like, and to suppress adverse effects on communication of other services due to route search processing.

  Further, since the search frame is a TCP SYN packet and the size is small, and the trace correspondence switch 1 holds the search frame, the trace correspondence switch 1 performs the search related to the received search frame and processing related to the transfer. The frame can be transmitted to the test terminal 2. As a result, the test terminal 2 can acquire information on the processing performed on the packet by the trace corresponding switch 1 on the path of the flow of the route search target.

  Further, when the search frame is transmitted from the test terminal 2 or transferred by the trace switch 1, the TTL value is set to an initial value of 1. When a router as a non-trace-capable switch that cannot identify a probe frame as a probe frame receives the probe frame, the router transmits an ICMP TIME EXCEEDED message to the test terminal 2 in accordance with the IP forwarding policy. Thereby, even when a router as a trace non-corresponding switch exists on the route of the flow to be searched for a route, the test terminal 2 can acquire information on the non-trace compatible switch.

  In addition, in the case of a non-trace switch that does not subtract TTL, its existence is not visible, but the search frame output by the trace support switch 1 in the preceding stage and the search frame received by the trace support switch 1 in the subsequent stage By comparing the contents, it is possible to indirectly detect that frame processing is being performed midway or FLOOD is being performed.

  In addition, when the test terminal 2 receives the ICMP TIME EXCEEDED message, the test terminal 2 sets the TTL value to 1 and transmits a search frame transfer instruction to the corresponding trace corresponding switch 1 to transfer the search frame again. . When the trace incompatible switch that has transmitted the ICMP TIME EXCEEDED message receives the search frame again, the normal transfer processing is performed, so that the path search processing is continued without interruption even when the trace non-compatible switches are mixed. . That is, even in a network in which SDN networks and networks other than the SDN network are mixed, the test terminal 2 can execute the route search process described in the first embodiment.

Further, by using the TCP SYN packet as the search frame, the destination host 3 returns a TCP SYN ACK packet as a response in the same manner as when receiving the user packet when receiving the search frame. As a result, the test terminal 2 can receive a response from the destination host 3 and can confirm communication with the host 3.

  In addition, when the test terminal 2 receives a search frame response from the trace corresponding switch 1, the test terminal 2 transmits a search frame response to the trace corresponding switch 1 that is a transfer source of the search frame that triggered the transmission of the search frame response. A TP frame including a discard instruction is transmitted. Accordingly, it is possible to suppress the memory consumption of the trace corresponding switch 1 by holding the search frame.

<Recording medium>
A program for causing a computer or other machine or device (hereinafter, a computer or the like) to realize any of the above functions can be recorded on a recording medium that can be read by the computer or the like. The function can be provided by causing a computer or the like to read and execute the program of the recording medium.

Here, a computer-readable recording medium is a non-temporary recording medium in which information such as data and programs is accumulated by electrical, magnetic, optical, mechanical, or chemical action and can be read from a computer or the like. A typical recording medium. Examples of such a recording medium that can be removed from a computer or the like include a flexible disk, a magneto-optical disk, a CD-ROM, a CD-R / W, a DVD, a Blu-ray disk, a DAT, an 8 mm tape, a flash memory, and the like. There are cards. In addition, as a recording medium fixed to a computer or the like, there are a hard disk, a ROM (read only memory), and the like. Further, an SSD (Solid State Drive) can be used as a recording medium removable from a computer or the like, or as a recording medium fixed to the computer or the like.

DESCRIPTION OF SYMBOLS 1 SDN switch, trace corresponding switch 2 Test terminal 3 Host 11A, 21 D plane line interface 11B, 28 M plane line interface 12A Frame reception control part 12B Frame transmission / reception control part 12C, 27 Management plane transmission / reception control part 13 Reception search frame HOLD control Unit 14 search frame response control unit 15 SDN-compatible switch control unit 16 next search frame HOLD control unit 17 next search frame output control unit 18, 26 TRACE PING transmission / reception control unit 22 D plane transmission / reception control unit 23 search frame transmission / reception control unit 24 route search Algorithm control unit 25 HMI control unit 101 CPU
102 Main storage device 105 Auxiliary storage device 107 Network interface

Claims (8)

A plurality of relay devices that transfer packets based on path information identified by packet identification information obtained from a combination of information included in the packet header;
A test device for searching for a route of a packet group having predetermined packet identification information;
Including
The test apparatus comprises:
A transmission unit for transmitting a search frame having the predetermined packet identification information;
When receiving a response to the search frame including identification information of the relay device from any of the plurality of relay devices, the identification information of the transmission source relay device is recorded in the list in the order of reception of the response from the response. Te, and a control unit that collects a part of the information indicating the path of the packet group,
When a response to the search frame including identification information of the relay device from any one of the plurality of relay devices is received, a storage unit of the transmission source relay device with respect to the relay device of the response transmission source A control frame transmission unit that transmits a control frame including a search frame transfer instruction stored in
Including
Each of the plurality of relay devices is
A storage unit that temporarily stores the search frame in a storage unit when the search frame is received;
A transmission unit that transmits a response to the search frame including identification information of the own device to the test device when the search frame is received;
A transfer unit that transfers the search frame stored in the storage unit according to packet identification information and the path information included in the search frame when a control frame including a transfer instruction of the search frame is received ;
Including an information processing system. The control unit of the test apparatus includes:
Relay device identification in which there is a response to the search frame from any of the plurality of relay devices, and the identification information of the relay device that is the transmission source of the response is collected as part of the information indicating the route of the packet group Detects anomalies and interrupts route search when in the information,
The information processing system according to claim 1 . The control unit of the test apparatus includes:
If a predetermined number of search frame responses are received within a predetermined time from reception of the response, an abnormality is detected and the route search is interrupted.
The information processing system according to claim 1 or 2 . The transmitter of the test apparatus is
The search frame is transmitted as TTL (Time To Live) = 1,
The control unit of the test apparatus includes:
When an ICMP TIME EXCEEDED message is received, the source IP address of the ICMP TIME EXCEEDED message is stored in the list as identification information of the second relay device that does not recognize the search frame, and 1 is added to the TTL value. The relay device corresponding to the identification information acquired from the response to the search frame immediately before the identification information of the second relay device in the list, the control frame instructing to transfer the search frame in the storage unit To
Each of the transfer units of the plurality of relay devices is
When a TTL value is specified in the control frame including the search frame transfer instruction from the test apparatus, the TTL of the search frame is set to the value specified in the control frame and transferred.
The information processing system according to any one of claims 1 to 3 . The transmitter of the test apparatus is
The search frame includes TCP SYN (Transmission Control Protocol SYNchronize).
) Use packet
The control unit of the test apparatus includes:
When a TCP SYN ACK (ACKnowledge) message is received, communication arrival at the destination device of the target flow is detected.
The information processing system according to any one of claims 1 to 4 . Each of the plurality of relay devices is
When receiving a control frame including an instruction to transfer the search frame from the test apparatus, a response transmission that transmits a response including the search frame before transfer in the storage unit and the search frame after processing related to transfer to the test apparatus. Further comprising
The control unit of the test apparatus includes:
When a response to the control frame is received, the search frame before transfer included in the response and the search frame after processing related to the transfer are recorded in a storage unit,
The information processing system according to any one of claims 1 to 5 . The control unit of the test apparatus includes:
From one of said plurality of relay devices, when receiving a response to the search frame, the relay device which transferred the search frame to the transmission source of the relay device of the response, in the storage unit of the relay device Transmitting a control frame including an instruction to discard the search frame;
The information processing system according to any one of claims 1 to 5 . A plurality of relay devices that transfer packets based on path information identified by packet identification information obtained from a combination of information included in the packet header;
A test device for searching for a route of a packet group having predetermined packet identification information;
An information processing method in an information processing system including:
The test apparatus comprises:
Transmitting a search frame having the predetermined packet identification information;
When receiving a response to the search frame including identification information of the relay device from any of the plurality of relay devices, the identification information of the transmission source relay device is recorded in the list in the order of reception of the response from the response. And collected as part of information indicating the route of the packet group,
When a response to the search frame including identification information of the relay device from any one of the plurality of relay devices is received, a storage unit of the transmission source relay device with respect to the relay device of the response transmission source Send a control frame that contains the transfer instruction of the exploration frame stored in
Each of the plurality of relay devices is
When the search frame is received, the search frame is temporarily stored in a storage unit,
When the probe frame is received, a response to the probe frame including identification information of the own device is transmitted to the test device,
When the control frame including the search frame transfer instruction is received, the search frame stored in the storage unit is transferred according to the packet identification information and the path information included in the search frame .
Information processing method.

Images