WO2016017737A1

WO2016017737A1 - Switch, overlay network system, communication method, and program

Info

Publication number: WO2016017737A1
Application number: PCT/JP2015/071611
Authority: WO
Inventors: 望嶋田
Original assignee: 日本電気株式会社
Priority date: 2014-07-31
Filing date: 2015-07-30
Publication date: 2016-02-04
Also published as: JPWO2016017737A1

Abstract

The purpose of the present invention is to improve a function of changing tunnel setting information for a switch that functions as a tunnel endpoint of an overlay network system. In the present invention, a switch that functions as a tunnel endpoint of an overlay network system is equipped with: a tunnel processing unit that performs capsulization and decapsulization of frames sent to and received from the opposing tunnel endpoint; and a command processing unit that, upon receiving an instruction to change flow identification information for identifying a capsulized frame, instructs the tunnel processing unit to receive the frame with flow identification information for before and after the change, and thereafter instructs the tunnel processing unit to change the flow identification information to be set in a frame being sent.

Description

Switch, overlay network system, communication method and program

[Description of related applications]
The present invention is based on a Japanese patent application: Japanese Patent Application No. 2014-156562 (filed on July 31, 2014), and the entire contents of this application are incorporated and incorporated herein by reference.
The present invention relates to a switch, an overlay network system, a communication method, and a program, and more particularly, a switch, an overlay network system, and a communication method that function as a tunnel endpoint that encapsulates and decapsulates a frame to be transmitted to and received from an opposite tunnel endpoint. And the program.

A type of overlay network system that builds a virtual layer 2 network on a layer 3 network is known. Of these, VXLAN (Virtual eXtensible Local Area Network) embeds UDP port information in an additional header and uses this to provide path control and load balancing functions. Non-Patent Document 1 is a draft of VXLAN (refer to the section of Page 10, Outer UDP Header).

Patent Document 1 discloses a management technique for a multicast tree in a configuration in which a large number of logical networks are constructed using a large-scale network logical partitioning technique such as VXLAN.

Non-Patent Documents 2 and 3 are OpenFlow white papers and OpenFlow specifications that are related technologies of the present invention.

Japanese Unexamined Patent Publication No. 2014-7681

The following analysis is given by the present invention. In the overlay network system, there is a demand for dynamically changing flow identification information (in the case of VXLAN, UDP port number) for identifying a flow by the physical network.

However, in order to realize this, it is necessary to change and set the flow identification information as a tunnel setting for a plurality of switches that function as tunnel endpoints of the overlay network system. At this time, if the setting timing is deviated, there is a problem that the network communication is interrupted.

An object of the present invention is to provide a switch, an overlay network system, a communication method, and a program that can contribute to an improvement in a tunnel setting change function of a switch that functions as a tunnel end point of an overlay network system.

According to a first aspect, there is provided a switch including a tunnel processing unit that performs encapsulation and decapsulation of a frame transmitted / received to / from an opposite tunnel endpoint as a tunnel endpoint of an overlay network. The switch further instructs the tunnel processing unit to receive a frame having flow identification information before and after the change, upon reception of a flow identification information change instruction for identifying the encapsulated frame. A command processing unit for instructing to change the flow identification information set in the transmission frame.

According to the second viewpoint, an overlay network system configured using the above-described switch is provided.

According to the third aspect, an encapsulated frame is identified as a tunnel end point of an overlay network in a switch having a tunnel processing unit that encapsulates and decapsulates a frame transmitted / received to / from an opposite tunnel end point. In response to reception of a flow identification information change instruction for sending, a step for instructing the tunnel processing unit to receive a frame having flow identification information before and after the change, and transmission at a predetermined opportunity after the instruction Instructing to change the flow identification information set in the frame. The method is tied to a specific machine called a switch that functions as a tunnel endpoint for the overlay network.

According to the fourth aspect, as a tunnel end point of an overlay network, encapsulation is performed on a computer mounted on a switch equipped with a tunnel processing unit that performs encapsulation and decapsulation of a frame transmitted to and received from an opposite tunnel end point. Triggered by reception of an instruction to change the flow identification information for identifying the received frame, a process for instructing the tunnel processing unit to receive a frame having flow identification information before and after the change, and after the instruction, In response to this, there is provided a program for executing processing for instructing change of flow identification information set in a transmission frame. This program can be recorded on a computer-readable (non-transient) storage medium. That is, the present invention can be embodied as a computer program product.

According to the present invention, it is possible to contribute to the improvement of the change function of the tunnel setting information of the switch that functions as the tunnel end point of the overlay network system.

It is a figure which shows the structure of the switch of one Embodiment of this invention. It is a figure which shows the structure of the overlay network system of the 1st Embodiment of this invention. It is a figure which shows the structure of the virtual switch of the 1st Embodiment of this invention. It is a figure which shows the structure of the flame | frame after encapsulation by the virtual switch of the 1st Embodiment of this invention. It is a figure which shows the structure of the tunnel process part in the virtual switch of the 1st Embodiment of this invention. It is a sequence diagram showing operation | movement of the 1st Embodiment of this invention. It is a figure which shows the UDP port number information (initial state) of the virtual switch of the 1st Embodiment of this invention. It is a figure which shows UDP port number information (after receiving UDP port number change notification) of the virtual switch of the first embodiment of the present invention. It is a figure which shows UDP port number information (after the notification of a change of a transmission UDP port number) of the virtual switch of the 1st Embodiment of this invention. It is a figure which shows the UDP port number information (after receiving the release notification of the UDP port number before change) of the virtual switch according to the first embodiment of this invention.

First, an outline of an embodiment of the present invention will be described with reference to the drawings. Note that the reference numerals of the drawings attached to this summary are attached to the respective elements for convenience as an example for facilitating understanding, and are not intended to limit the present invention to the illustrated embodiment.

In one embodiment of the present invention, as shown in FIG. 1, a tunnel processing unit 260a that performs encapsulation and decapsulation of a frame to be transmitted to and received from an opposite tunnel endpoint as a tunnel endpoint of an overlay network, and a command This can be realized by the switch 200a including the processing unit 251a.

More specifically, the command processing unit 251a changes the tunnel processing unit 260a in response to the reception of a flow identification information change instruction (eg, AAA → BBB) for identifying the encapsulated frame. The reception of a frame having preceding and following flow identification information (flow identification information = reception of AAA and BBB frames) is instructed. Then, at a predetermined opportunity, the tunnel processing unit 260a is instructed to change the flow identification information set in the transmission frame. It should be noted that the predetermined trigger may be based on the passage of a certain period from the reception of the flow identification information change instruction, or an explicit instruction from the user (instruction for changing the flow identification information set in the transmission frame). It may be conditional on being done.

By configuring as described above, it is possible to suppress the occurrence of communication disconnection due to the change of the flow identification information used for tunnel communication. The reason for this is that when the flow identification information change instruction is received, the flow identification information of the frame to be received is not changed immediately, but the flow identification information before and after the change is received first, and then used for transmission. In other words, it is configured to absorb the deviation of the setting timing by changing the flow identification information.

[First Embodiment]
Next, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 is a diagram illustrating a configuration of the overlay network system according to the first embodiment of this invention. Referring to FIG. 2, a plurality of virtual switches 200A to 200C arranged as tunnel end points of the overlay network system, a flow control device 100 that controls these virtual switches 200, and these virtual switches 200 are used to communicate with each other. A configuration including virtual machines 300A to 300E is shown. Between the virtual switches 200, VXLAN tunnels 400AB-1 to 400BC-2, which will be described later, are constructed. Hereinafter, when the virtual switches 200A to 200C, the virtual machines 300A to 300E, and the VXLAN tunnels 400AB-1 to 400BC-2 are not particularly distinguished, they are referred to as “virtual switch 200”, “virtual machine 300”, and “VXLAN tunnel 400”, respectively. .

The flow control device 100 performs flow management for constructing the VXLAN tunnel 400 in a mesh shape between the virtual switches 200, and instructs flow setting to one or more virtual switches 200. Thereby, the flow control apparatus 100 realizes a communication network between the virtual machines 300. Such a flow control device 100 can be realized by adding a tunnel management function to the OpenFlow controllers of Non-Patent Documents 2 and 3.

The virtual switch 200 selects a flow entry having a matching condition that matches the input frame from the flow entries set by the instruction of the flow control apparatus 100 for the input frame from the virtual machine 300 or another virtual switch. To process the input frame. The virtual switch 200 outputs the input frame to the VXLAN tunnel 400 for connection with the other virtual machine 300 according to the selected flow entry, and outputs it to the other virtual switch 200 across the base network 500, or the flow control device 100. Output to or drop.

The virtual machine 300 transmits a frame addressed to the other virtual machine 300 to the virtual switch 200 and receives a frame originating from the other virtual machine 300 from the virtual switch 200. Further, the virtual machine 300 does not need to be directly connected to the virtual switch 200 and may be connected via a layer 2 switch (L2SW), or the virtual machine 300 is a layer 3 switch (L3SW) or a router. In some cases, another virtual machine 300 is connected to the destination.

Further, the virtual switch 200 and the virtual machine 300 in the connected state may be virtual entities that operate on the same virtualization server by using server virtualization technology.

The VXLAN tunnel 400 is an overlay tunnel for performing communication between the virtual switches 200 via the infrastructure network 500. There is one for each combination of two virtual switches 200 that communicate with a virtual network identifier VNI (VXLAN Network Identifier). In the example of FIG. 2, two VNI VXLAN tunnels 400 are respectively constructed between three virtual switches. In the following description, the VXLAN tunnel 400 with VNI = 1 between the virtual switch 200A and the virtual switch 200B is represented in the form of VXLAN tunnel 400AB-1.

The infrastructure network 500 is a layer 3 network or the like for performing frame transfer between the virtual switches 200. In this embodiment, the infrastructure network 500 can communicate with a destination IP address given when encapsulated in VXLAN, and when a multicast address is set as the destination, all virtual switches 200 It can be delivered to.

FIG. 3 is a diagram illustrating a configuration of the virtual switch according to the first embodiment. Referring to FIG. 3, the configuration includes a flow entry search unit 201, a flow entry storage unit 202, a flow entry processing unit 203, a flow processing unit 204, a flow control device communication unit 205, and a VXLAN processing unit 250. It is shown. Among these, the flow entry search unit 201, the flow entry storage unit 202, the flow entry processing unit 203, the flow processing unit 204, and the flow control device communication unit 205 correspond to the open flow switch function unit.
Is done.

The VXLAN processing unit 250 and the command processing unit 251 and the tunnel processing units 260-1 and 260-2 (hereinafter referred to as “tunnel processing unit 260” unless the tunnel processing units 260-1 and 260-2 are particularly distinguished). And. The tunnel processing unit 260 passes the VXLAN-encapsulated frame input from the VXLAN tunnel 400 to the flow entry search unit 201, and performs VXLAN decapsulation as necessary according to the instruction of the flow processing unit 204, and outputs it to the virtual machine 300. In addition, the tunnel processing unit 260 passes the frame input from the virtual machine 300 to the flow entry search unit 201, encapsulates VXLAN as necessary in accordance with the instruction of the flow processing unit 204, and establishes a virtual interface facing through the VXLAN tunnel 400. A process of transferring to the switch 200 is performed.

The command processing unit 251 receives an operation from the user and outputs a UDP port number information change command or the like to the tunnel processing unit 260.

The flow entry search unit 201 extracts flow entry search condition information for searching for a flow entry from the input frame, and searches the flow entry storage unit 203 using the flow entry search condition information. As a result of the search, the flow entry search unit 201 passes the action and input frame of the matched flow entry to the flow processing unit 204. In addition, the flow entry search unit 201 updates the time-out time and statistical information of the flow entry matched at that time, if any.

The flow entry storage unit 202 uses a flow entry table set by the flow control device 100 and the like. The change of the flow entry in the flow entry storage unit 202 is reported to the flow control apparatus 100 and grasped. Therefore, the flow control apparatus 100 can grasp and control the behavior of the virtual switch 200.

The flow entry processing unit 203 updates the flow entry storage unit 202 in accordance with an operation instruction or a reference instruction such as addition / deletion regarding a flow entry coming from the flow control apparatus 100 via the flow control apparatus communication unit 205. Further, the flow entry processing unit 203 refers to the flow entry storage unit 202, deletes the flow entry that has timed out, and sends the flow entry to the flow control device 100 via the flow control device communication unit 205. Report that it has been deleted.

The flow processing unit 204 changes the value of the frame according to the input frame and its action passed from the flow control device 100 via the flow entry search unit 201 or via the flow control device communication unit 205, A frame is output or a frame is output to another virtual switch 200. Further, as necessary, the flow processing unit 204 instructs the VXLAN processing unit 250 to perform VXLAN encapsulation, outputs it to the VXLAN tunnel 400, performs VXLAN decapsulation of a frame input from the VXLAN tunnel 400, A frame is output to the flow control device 100 via the control device communication unit 205 or dropped.

FIG. 4 is a diagram illustrating a configuration of a frame that is VXLAN encapsulated by the virtual switch according to the first embodiment of this invention. When performing VXLAN encapsulation, the tunnel processing unit 260 of the VXLAN processing unit 250 encapsulates the original frame with additional headers such as Outer MAC, Outer IP, Outer UDP, and VXLAN ID. Of these, UDP

port information numbers

601 and 602 described later are set in the Outer UDP header, which can be used for flow identification and load distribution (load balancing) using the same. In the case of decapsulation, processing for removing the additional header from the encapsulated frame is performed.

FIG. 5 is a diagram illustrating a configuration of the tunnel processing unit 260 in the virtual switch 200 according to the first embodiment. Referring to FIG. 5, a configuration including a VNI information storage unit 264, a tunnel release unit (decapsulation unit) 265, a UDP port information storage unit 266, and a tunneling unit (encapsulation unit) 267 is shown. Yes.

The VNI information storage unit 264 holds a virtual network identifier (VNI) of VXLAN that the tunnel processing unit 260 has. This virtual network identifier (VNI) is stored in the VXLAN header of FIG.

The tunnel release unit (decapsulation unit) 265 performs decapsulation by removing an additional header from the VXLAN frame of the frame input from the VXLAN tunnel 400.

The UDP port information storage unit 266 holds UDP port information for the tunnel processing unit 260 to perform transmission / reception via the VXLAN tunnel 400. The UDP port number held in the UDP port information storage unit 266 is changed by a change command issued from the command processing unit 251. The UDP port information storage unit 266 can be shared by a plurality of tunnel processing units 260. That is, one UDP port number can be used for a plurality of VNIs.

When outputting to the VXLAN tunnel 400, the tunneling unit (encapsulating unit) 267 performs VXLAN encapsulation processing by adding an additional header to the original frame as shown in FIG.

The command processing unit 251 receives an operation from the user, outputs a UDP port number information change command (UDP port number change notification) or the like to the tunnel processing unit 260, and rewrites the contents or the like of the UDP port information storage unit 266. Perform the action.

In this embodiment, the command processing unit 251 is provided to change the UDP port information storage unit 266. However, the configuration is changed by transmitting / receiving a special frame / packet for changing the UDP port number. It is also possible to perform this.

3 and 5 is realized by a computer program that causes a computer mounted on the virtual switch 200 to execute the above-described processes using the hardware thereof. You can also.

Subsequently, the operation of the present embodiment will be described in detail with reference to the drawings. FIG. 6 is a sequence diagram showing the operation of the first exemplary embodiment of the present invention.

As an initial state, as shown in FIG. 7, it is assumed that # 1 is set in the UDP port information storage unit 266 as a UDP port number used for VXLAN communication. Specifically, as shown in FIG. 7, at this time, only the UDP port number # 1 can receive a frame, and the UDP port number # 1 is set as the destination UDP port number at the time of frame transmission.

In this state, as shown in FIG. 6, it is assumed that the user instructs each virtual switch 200 to change the UDP port number in order to switch the settings of all the virtual switches 200A to 200C. Upon receiving the instruction, the command processing unit 251 transmits a UDP port number change command (first instruction) for instructing the tunnel processing unit 260 to change the UDP port number from # 1 to # 2. (S001 in FIG. 6).

The content of the UDP port information storage unit 266 of the tunnel processing unit 260 that has received the UDP port number change command (first instruction) is rewritten as shown in FIG. 8 (S002 in FIG. 6). In the example of FIG. 8, an entry specifying UDP port number # 2 as a receivable port is added to the entry of FIG. At this time, the UDP port number # 2 is not the UDP port information used for the transmission destination (the transmission destination use field is NO).

Next, the user inputs a command for switching the transmission destination port to the new UDP port number # 2 to the virtual switch 200. Upon receiving the instruction, the command processing unit 251 instructs the tunnel processing unit 260 to change the UDP port number used as the destination at the time of transmission from # 1 to # 2 (second port number switching command (second (Instruction) is transmitted (S003 in FIG. 6).

When the UDP port number switching command (second instruction) is received, the transmission destination use field in the UDP port information storage unit 266 of the tunnel processing unit 260 is rewritten as shown in FIG. 9 (S004 in FIG. 6). In the example of FIG. 9, the transmission destination use field of the first entry in FIG. 8 is rewritten from YES to NO, and the transmission destination use field of the second entry of FIG. 8 is rewritten from NO to YES. This process corresponds to a process of switching from the UDP port number # 1 used for transmission destination to # 2. At this time, both UDP port numbers # 1 and # 2 are set as receivable UDP ports (both receivable port fields are YES).

Next, the user inputs a command for instructing the virtual switch 200 to open the pre-change UDP port number # 1. Upon receiving the instruction, the command processing unit 251 transmits a pre-change UDP port number release command (third instruction) to the tunnel processing unit 260 (S005 in FIG. 6).

The content of the UDP port information storage unit 266 of the tunnel processing unit 260 that has received the pre-change UDP port number release command (third instruction) is rewritten as shown in FIG. 10 (S006 in FIG. 6). In the example of FIG. 10, the UDP port number # 1 is removed from the receivable UDP port of the first entry of FIG. 9 (changed from YES to NO). As a result, the UDP port number # 1 is released. In the example of FIG. 10, the first entry is left in a state where NO is set in each field, but this entry is reused when changing from UDP port # 2 to # 1 again. Of course, if there is no necessity, the first entry itself may be deleted.

As described above, according to the present embodiment, even when the change setting timing of the UDP port number shifts with respect to each virtual switch constituting the system, it is possible to suppress the occurrence of network communication disconnection. .

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and further modifications, substitutions, and adjustments are possible without departing from the basic technical idea of the present invention. Can be added. For example, the network configuration, the configuration of each element, and the expression form of a message shown in each drawing are examples for helping understanding of the present invention, and are not limited to the configuration shown in these drawings.

For example, in the first embodiment described above, the user can change the UDP port number (first instruction), the UDP port number switching command (second instruction), the pre-change UDP port number release command (third instruction). However, the switching of the UDP port number and the release of the pre-change UDP port number can be performed automatically after a lapse of a predetermined period. Further, when it is not necessary to release the pre-change UDP port number, the pre-change UDP port number release may be omitted.

In addition, the flow control apparatus 100 on behalf of the user performs a UDP port number change command (first instruction), a UDP port number switching command (second instruction), a pre-change UDP port number release command (third instruction). Instruction) issuance instruction may be sent to the command processing unit 251. In this case, the flow control apparatus 100 can change the UDP port number with reference to a communication policy applied to the virtual machine.

For example, in the above-described first embodiment, the virtual switch 200 has been described by assuming that it is connected by VXLAN, but the switch to which the present invention is applied is not limited to the virtual switch. For example, some or all of the switches may be physical switches.

Also, for example, in the first embodiment described above, the tunnel processing unit 260 passes the VXLAN-encapsulated frame input from the VXLAN tunnel 400 to the flow entry search unit 201, and in accordance with the instructions of the flow processing unit 204, In the above description, the VXLAN decapsulation is performed. However, the tunnel processing unit 260 may perform the VXLAN decapsulation and then pass the frame to the flow entry search unit 201. Similarly, when transmitting a frame received from a virtual machine, the input frame may be VXLAN encapsulated and then passed to the flow entry search unit 201.

Finally, a preferred form of the invention is summarized.
[First embodiment]
(Refer to the switch from the first viewpoint above.)
[Second form]
In the switch of the first form,
The command processing unit
In response to the reception of the first instruction, the tunnel processing unit is instructed to start frame reception with the flow identification information before and after the change,
A switch for instructing the tunnel processing unit to start storing the flow identification after the change to the transmission frame upon reception of the second instruction.
[Third embodiment]
In the switch of the first or second form,
The command processing unit
A switch that instructs the tunnel processing unit to end frame reception with the flow identification information before the change upon reception of the third instruction.
[Fourth form]
In the switch of any one of the first to third forms,
The flow identification information is a switch that is a UDP (User Datagram Protocol) port number.
[Fifth embodiment]
In the switch according to any one of the first to fourth aspects,
Furthermore, a switch comprising an OpenFlow switch function unit for processing a received frame after decapsulation and a transmission frame before encapsulation.
[Sixth embodiment]
In the switch of the fifth form,
A switch that receives an instruction to change the flow identification information from a control device that receives instructions regarding processing of the received frame after decapsulation and a transmission frame before encapsulation.
[Seventh form]
(Refer to the overlay network system from the second viewpoint)
[Eighth form]
(Refer to the communication method according to the third viewpoint)
[Ninth Embodiment]
(Refer to the program from the fourth viewpoint above.)
Note that the seventh to ninth embodiments can be developed into the second to sixth embodiments as in the first embodiment.

It should be noted that the disclosures of the above patent documents and non-patent documents are incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiments and examples can be changed and adjusted based on the basic technical concept. Various combinations or selections of various disclosed elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) are possible within the scope of the disclosure of the present invention. It is. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea. In particular, with respect to the numerical ranges described in this document, any numerical value or small range included in the range should be construed as being specifically described even if there is no specific description.

DESCRIPTION OF SYMBOLS 100 Flow control apparatus 200, 200A-200C Virtual switch 200a Switch 201 Flow entry search part 202 Flow entry memory | storage part 203 Flow entry process part 204 Flow process part 205 Flow control apparatus communication part 250 VXLAN process part 251,251a

Command process part

260, 260a, 260-1, 260-2 Tunnel processing unit 264 VNI information storage unit 265 Tunnel release unit (decapsulation unit)
266 UDP port information storage unit 267 Tunneling unit (encapsulation unit)
300, 300A to 300E Virtual machine 400, 400AB-1 to 400BC-2 VXLAN tunnel 500

Base network

601, 602 UDP port number information

Claims

As a tunnel endpoint of the overlay network, a tunnel processing unit that performs encapsulation and decapsulation of a frame to be transmitted / received to / from an opposite tunnel endpoint,
Upon receiving a flow identification information change instruction for identifying an encapsulated frame, the tunnel processing unit is instructed to receive a frame having flow identification information before and after the change, and then set to a transmission frame. A command processing unit for instructing to change flow identification information;
A switch characterized by comprising.
The command processing unit
In response to the reception of the first instruction, the tunnel processing unit is instructed to start frame reception with the flow identification information before and after the change,
The switch according to claim 1, which instructs the tunnel processing unit to start storing the flow identification after the change to the transmission frame upon reception of the second instruction.
The command processing unit
3. The switch according to claim 1, wherein, upon reception of the third instruction, the tunnel processing unit is instructed to end frame reception with the flow identification information before the change.
The switch according to any one of claims 1 to 3, wherein the flow identification information is a UDP (User Datagram Protocol) port number.
Furthermore, the switch according to any one of claims 1 to 4, further comprising an OpenFlow switch function unit for processing a received frame after decapsulation and a transmission frame before encapsulation.
6. The switch according to claim 5, wherein the switch for receiving the flow identification information is received from a control device that receives instructions for processing the received frame after decapsulation and the transmission frame before encapsulation.
As a tunnel endpoint of the overlay network, a tunnel processing unit that performs encapsulation and decapsulation of a frame to be transmitted / received to / from an opposite tunnel endpoint,
Upon receiving a flow identification information change instruction for identifying an encapsulated frame, the tunnel processing unit is instructed to receive a frame having flow identification information before and after the change, and then set to a transmission frame. A command processing unit for instructing to change flow identification information;
An overlay network system configured by using a switch equipped with.
As a tunnel endpoint of the overlay network, in a switch with a tunnel processing unit that performs encapsulation and decapsulation of frames sent and received with the opposite tunnel endpoint,
Instructing the tunnel processing unit to receive a frame having flow identification information before and after the change, upon reception of a change instruction of flow identification information for identifying the encapsulated frame;
Instructing the change of the flow identification information set in the transmission frame at a predetermined opportunity after the instruction;
Including a communication method.
As a tunnel endpoint of the overlay network, a computer mounted on a switch equipped with a tunnel processing unit that performs encapsulation and decapsulation of frames sent and received with the opposite tunnel endpoint,
Triggering reception of a flow identification information change instruction for identifying an encapsulated frame, a process for instructing the tunnel processing unit to receive a frame having flow identification information before and after the change,
A process of instructing to change the flow identification information set in the transmission frame at a predetermined opportunity after the instruction;
A program that executes