KR20160018412A - Method and apparatus for changing role of controller in software defined networking environment - Google Patents

Abstract

Disclosed are a method and an apparatus for changing a role of a controller in an SDN environment consisting of multiple controllers. The method for changing a role of a controller is performed by a switch for changing the role of the controller in the SDN environment and includes the following steps: receiving a roll change message from a first controller for requesting master authority; and changing the first controller into a master controller by transmitting a role change response message including transaction information of a packet, which is finally processed by the switch, to the first controller. Therefore, a method and a time for transmitting a message for notifying that a role has been changed from a master to a slave to a controller which has functioned as the master are specified. Consequently, continuity of a server can be ensured.

Description

[0001] METHOD AND APPARATUS FOR CHANGING ROLE OF CONTROLLER IN SOFTWARE DEFINED NETWORKING ENVIRONMENT [0002]

The present invention relates to SDN (Software Defined Networking) technology, and more particularly, to a method and apparatus for changing the role of a controller in an SDN environment composed of multiple controllers.

SDN (Software Defined Networking) is a network architecture in which the control plane and the data plane are physically separated from each other, and is a next generation networking technology that has recently become an issue in the communication market.

On the SDN basis, the control plane can be programmed by software to enable remote automatic control of the network equipment, which enables the carrier to operate the network more flexibly.

In recent years, the standardization of technologies for efficiently operating the communication system by separating the traffic forwarding function of the switch and the control function of the switch has been carried out by the Open Networking Foundation (ONF), Internet Engineering Task Force (IETF), European Telecommunications Standards Institute (ETSI) ISG NFV (Network Function Virtualization) and ITU-T (International Telecommunications Union Telecommunication).

Among these, the Open Networking Foundation (ONF) standardization group which is one of the SDN technologies, OpenFlow technology standardization, is briefly mentioned simply. The SDN environment consists of a plurality of SDN controllers and the switches can be connected to one or more SDN controllers. Here, SDN controllers are divided into three roles: Master, Slave, Equal, and can exchange information between SDN controllers through separate channels.

However, there is no definition of a time when a message indicating that the state has been changed to the slave role is given to a controller having a plurality of initial master roles in the ONF as well as other standardization bodies. As a result, the controller of the initial master role is changed to the slave The control messages sent to the switch are ignored by the switch before being notified.

In order to solve the above problems, an object of the present invention is to provide a method and system for transmitting a message informing that a switch has changed roles from a master to a slave to a controller that has previously served as a master in an SDN environment including a plurality of controllers And a method for embodying the same.

Another object of the present invention is to provide a method of reducing a loss caused by transferring a control message to a switch in a state in which a controller that has previously acted as a master has not recognized that its role is changed to a slave .

According to an aspect of the present invention, there is provided a method for changing a role of a controller in a software defined networking environment, the method comprising: receiving a role change message from a first controller requesting a master authority; Receiving; And changing the first controller to the master controller by transmitting a role change response message including the transaction information of the packet that the switch last processed to the first controller.

Here, the role change response message may further include an IP address of a second controller which is an existing master controller.

Here, the method may further include setting a second controller as a slave controller by transmitting a status setting message for setting a second controller, which is an existing master controller, as a slave controller to the second controller.

Here, the status setting message may be transmitted to the second controller by a first controller that is changed to a switch or a master controller.

Here, the status setting message may include transaction information of a packet finally processed by the switch.

Here, the step of setting the second controller as the slave controller may be performed by changing the first controller to the master controller and then transmitting the status setting message to the second controller after a predetermined time has elapsed.

Here, the step of setting the second controller as a slave controller may include switching a first controller to a master controller, and then, when the second controller transmits a control message to the switch, And transmitting it.

According to another aspect of the present invention, there is provided a method of changing roles of a controller, the method comprising: a first controller requesting a master authority in a software defined networking environment; Transmitting a role change message to a switch; Changing a role to a master controller by receiving a role change response message including a transaction information of a packet that the switch has finally processed from the switch; And setting a second controller as a slave controller by transmitting a status setting message for setting a second controller, which is an existing master controller, as a slave controller to the second controller.

The method includes receiving packet information to be processed by the switch from a second controller in response to a status setting message; And controlling the switch to process the packet according to the packet information to be processed by the switch.

According to another aspect of the present invention, there is provided a method for changing roles of a controller, the method comprising: a controller for performing a role change in a controller performed in a second controller that is an existing master controller in a software defined networking environment, Setting a second controller as a slave controller by receiving a status setting message including transaction information of one packet; And transmitting the packet information to be processed by the switch to the first controller changed to the master controller in response to the status setting message.

Here, the status setting message may be received after a predetermined time elapses after the first controller is changed to the master controller.

Here, the status setting message may be received when the second controller transmits a control message to the switch after the first controller is changed to the master controller.

The method of changing the role of the controller according to the present invention as described above includes a step of storing the transaction information of the packet finally processed by the switch in the message informing that the role has changed from the master to the slave to the controller, The controller can reduce the loss caused by transferring the control message to the switch without recognizing that the role of the controller has changed to the slave.

In addition, it is possible to guarantee continuity of service by specifying the transmission technique and timing of the message informing that the role which has been changed from the master to the slave to the controller which has previously served as the master has been changed.

1 is a flowchart showing a process of establishing a connection between a controller and a switch.
Fig. 2 is a flowchart for explaining a general process of changing roles of the controller.
3 is a flowchart illustrating a process of changing a role of a controller according to an embodiment of the present invention
4 is a flowchart illustrating a process of changing roles of a controller according to another embodiment of the present invention.
5 is a flowchart illustrating a process of changing roles of a controller according to another embodiment of the present invention.
6 is a block diagram for explaining a configuration of an apparatus for performing a role change of a controller according to an embodiment of the present invention.
7 is an exemplary diagram for explaining a message for performing a role change of a controller according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, A, B, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, the controller referred to in the present invention refers to a functional entity that controls related components (for example, a switch, a router, and the like) to stably provide an SDN service. And the like. For example, a controller means a controller functional entity defined by ONF, IETF, ETSI, and / or ITU-T.

The network device referred to in the present invention refers to a functional element that substantially forwards, switches, or routes traffic (or packets). The network device includes switches, routers, and routers defined by ONF, IETF, ETSI and / or ITU- Switch element, router element, forwarding element, and the like.

In addition, the controller (master controller) serving as a master referred to in the present invention means a controller that primarily controls at least one switch, and may be constituted by one or more. The slave / equal controller (slave / equal controller) means a controller that replaces the function of the master controller when the master controller can not control the switch due to various reasons. do.

Also, in the embodiments of the present invention, the operation for changing the role of the controller is shown using the parameters and / or message type (e.g., a flow table entry) defined in the ONF. However, But is not limited to the defined contents.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart illustrating a process of establishing a connection between a controller and a switch, and FIG. 2 is a flowchart illustrating a general process of changing a role of a controller.

Referring to FIG. 1, the switch may initiate a 3-way handshake on the IP address of the SDN controller to establish a TCP connection (S110). Here, for the configuration of the SDN environment, the IP address of the SDN controller to control the switch in advance can be set in the switch.

After establishing the TCP connection, the SDN controller and the switch may exchange the Hello message to verify the version of the open flow protocol (S121, S123).

After confirming the version of the open flow protocol, the FeaturesRequest message and the FeaturesReply message can be exchanged (S131, S133) to confirm the functions supported by the switch.

After confirming the functions supported by the switch, the SDN controller can notify the switch of a SetConfiguration message to send the necessary settings to the switch (S140).

Finally, StatusRequest and StatusReply messages can be exchanged to check the status of the switch (S151, S153).

Referring to FIG. 2, the SDN controller and the switch are connected through a procedure shown in FIG. 1, and a message for changing the role of the controller can be exchanged in a state where communication is ready.

The switch can be connected to a plurality of controllers and can be controlled by a plurality of controllers.

For example, the switch can be established with the first controller and the second controller through the procedure shown in FIG. 1 (S100).

2, the first controller means a controller whose role is changed from a slave controller to a master controller, and the second controller means a controller whose role is changed from a master controller to a slave controller.

First, the first controller acting as a slave controller can transmit a role change message requesting the master authority to the switch (S211).

The switch may change the first controller to the master controller by sending a role change response message to the first controller in response to the role change message of the first controller (S213). That is, the switch may accept the role change by sending a role change response message to the first controller.

Therefore, the switch recognizes the first controller as the master controller and the second controller as the master controller as the slave controller.

However, even if the switch recognizes the second controller as a slave controller, the second controller may not have received a controller role status message that the role of the second controller has changed to the slave controller from the switch.

That is, since the second controller does not recognize that its role is changed to the slave controller, it can transmit a control message to the switch. In this case, the switch can ignore the control message of the second controller (S220).

Accordingly, after the switch receives the control message, a case may occur in which the controller role status message in which the role of the second controller is changed to the slave controller is transmitted to the second controller (S230). As a result, There arises a problem that omission may occur.

3 is a flowchart illustrating a process of changing a role of a controller according to an embodiment of the present invention

Referring to FIG. 3, the switch can be established with the first controller and the second controller through the procedure shown in FIG. 1 (S100).

3, the first controller means a controller whose role is changed from a slave controller to a master controller, and the second controller means a controller whose role is changed from a master controller to a slave controller.

First, the first controller acting as the slave controller can transmit a role change message requesting the master authority to the switch (S311).

The switch transmits a role change response message to the first controller in response to the role change message of the first controller, including the IP of the second controller and the transaction information of the packet finally processed by the switch, (S213). Here, the transaction information of the packet finally processed by the switch may mean a transaction ID. That is, the switch accepts the role change by transmitting the role change response message to the first controller, and at the same time, the information of the second controller and the information of the transaction finally processed by the switch can be transmitted to the first controller converted into the master controller have.

The first controller can set the second controller as a slave controller by transmitting a status setting message for setting a second controller, which is an existing master controller, as a slave controller to the second controller (S321).

In this case, the second controller may transmit the packet information to be processed by the switch to the first controller by including the transaction information of the packet finally processed by the switch in the status setting message (S323).

Accordingly, the first controller may exchange messages with the switch to process the unprocessed packet based on the packet information to be processed by the switch received from the second controller (S330).

4 is a flowchart illustrating a process of changing roles of a controller according to another embodiment of the present invention.

Referring to FIG. 4, the switch can be connected to the first controller and the second controller through the procedure shown in FIG. 1 (S100).

4, the first controller means a controller whose role is changed from a slave controller to a master controller, and the second controller means a controller whose role is changed from a master controller to a slave controller.

The first controller and the second controller negotiate with each other over a separate channel to share information such as a topology map (connection information between the controller and the switch) of the SDN network (S401).

The first controller acting as the slave controller can transmit a role change message requesting the master authority to the switch (S411).

The switch can change the first controller to the master controller by transmitting a role change response message including the transaction information of the packet finally processed by the switch to the first controller in response to the role change message of the first controller (S413) . Here, the transaction information of the packet finally processed by the switch may mean a transaction ID.

The switch may transmit the role change response message to the first controller to accept the role change and finally transmit the information of the transaction processed by the switch to the first controller converted to the master controller. That is, by mutually sharing the information about the topology map through S401, the role change response message may not need to include information about the IP of the second controller.

The first controller may set the second controller as a slave controller by transmitting a status setting message to the second controller to set the second controller as a slave controller as an existing master controller (S421).

Here, the second controller may transmit the packet information to be processed by the switch to the first controller by including the transaction information of the packet finally processed by the switch in the status setting message (S423).

Accordingly, the first controller may exchange messages with the switch to process the unprocessed packet based on the packet information to be processed by the switch received from the second controller (S430).

5 is a flowchart illustrating a process of changing roles of a controller according to another embodiment of the present invention.

Referring to FIG. 5, the switch can be established with the first controller and the second controller through the procedure according to FIG. 1 (S100).

5, the first controller means a controller whose role is changed from a slave controller to a master controller, and the second controller means a controller whose role is changed from a master controller to a slave controller.

First, the first controller acting as the slave controller can transmit a role change message requesting the master authority to the switch (S511).

The switch transmits a role change response message to the first controller in response to the role change message of the first controller, including the IP of the second controller and the transaction information of the packet finally processed by the switch, (S513). Here, the transaction information of the packet finally processed by the switch may mean a transaction ID. That is, the switch accepts the role change by transmitting the role change response message to the first controller, and at the same time, the information of the second controller and the information of the transaction finally processed by the switch can be transmitted to the first controller converted into the master controller have.

The switch may operate the timer after changing the first controller to the master controller (S520).

The switch can determine that a preset time has elapsed according to the operation of the timer (S531).

If it is determined that the preset time has elapsed according to the operation of the timer, the switch can set the second controller as the slave controller by transmitting the status setting message to the second controller (S533).

If it is not determined that the predetermined time has elapsed according to the operation of the timer, the switch can determine whether the switch has received the control message from the second controller (S541).

If it is determined that the control message is received from the second controller, the switch can set the second controller as the slave controller by transmitting the status setting message to the second controller (S534).

In addition, the switch may decrease the time of the timer until receiving the control message from the second controller (S550), and after the first controller is changed to the master controller, the switch continuously determines whether a predetermined time has elapsed .

6 is a block diagram for explaining a configuration of an apparatus for performing a role change of a controller according to an embodiment of the present invention.

Referring to FIG. 6, a method of changing the role of the controller according to an embodiment of the present invention may be performed by interlocking the controller 100 and the switch 200.

First, the controller 100 includes a flow table management unit 110, a switch interlock processing unit 120, and a role change processing unit 130. [

The flow table management unit 110 may store and manage parameters and flow tables for synchronizing the flow tables for the plurality of switches 200. [

The switch interlocking processing unit 120 processes the protocol so that the plurality of switches 200 and the controller 100 can communicate with each other.

The role change processing unit 130 may perform a function of transmitting and receiving a role change message and a status setting message in order to set, change, etc. the role of the controller 100 with respect to the switch 200. [ That is, the role change processing unit 130 transmits the role change message to the switch 200 or processes the status setting message received from the switch 200 to change the role of the controller 100 from master to slave, Can be set / changed.

Next, the switch 200 includes a flow table management unit 210, a controller interlock processing unit 220, a controller role management unit 230, and a timer management unit 240.

The flow table management unit 210 may store and manage parameters and flow tables for synchronizing the flow table for the switch 200 itself.

The controller interlock processing unit 220 processes the protocol so that the controller 100 and the switch 200 can communicate with each other.

The controller role management unit 230 transmits and receives a role change message and a status setting message to set, change, and so on the role of the controller 100 with respect to the switch 200. [ That is, the controller role management unit 230 receives the role change message from the controller 100 and processes the status change message, or transmits the status setting message to the controller 100 to change the role of the controller 100 from master to slave or from slave to master Can be set / changed.

The timer management unit 240 allows the elapsed time to be checked after changing the first controller, which was a slave controller, to the master controller. For example, after the first controller is changed to the master controller, the timer management unit 240 may notify the controller role management unit 230 of a predetermined time.

Therefore, the controller role managing unit 230 may change the first controller to the master controller, and then transmit the status setting message to the second controller, which is the master controller, after a preset time has elapsed.

The configurations of the controller 100 and the switch 200 according to the embodiment of the present invention are described as being arranged in the respective constituent parts for convenience of explanation. However, at least two of the constituent parts may be combined to form one constituent part, The constituent parts can be divided into a plurality of constituent parts to carry out the function and the case of the integrated and separate embodiments of each constituent part is also included in the scope of the present invention unless the essence of the present invention is satisfied.

In addition, the operation of the controller 100 and the switch 200 according to the embodiment of the present invention can be implemented as a computer-readable program or code on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. The computer-readable recording medium may also be distributed and distributed in a networked computer system so that a computer-readable program or code can be stored and executed in a distributed manner.

7 is an exemplary diagram for explaining a message for performing a role change of a controller according to an embodiment of the present invention.

FIG. 7 is a flowchart illustrating a method for changing a role of a controller according to an exemplary embodiment of the present invention. Referring to FIG. 7, An example of the main parameters is shown.

In detail, transaction information of a packet finally processed by the switch and information on the IP of the second controller, which is an existing master controller, can be additionally defined in the controller change request and response message.

For example, the transaction information of the last packet processed by the switch is' unit32_t xid; / * Transaction id associated with final processed packet. * / ', And the IP of the second controller, which is an existing master controller, is represented by' unit32_t controller_ip; / * IP address of the master controller. * / '.

FIG. 7 exemplarily illustrates the message of the OpenFlow standard, but it is only a specific standard selected to describe the technical idea of the present invention from a standard viewpoint, and the idea of the present invention is limited to a message format conforming to the OpenFlow standard But it can be expressed in various message formats defined by other standardization bodies.

The method of changing the role of the controller according to the embodiment of the present invention includes a step of storing the transaction information of the packet finally processed by the switch in a message informing that the role has changed from the master to the slave to the controller, It is possible to reduce the loss caused by transmitting a control message to the switch in a state in which the controller acting as a master does not recognize that its role is changed to a slave.

In addition, it is possible to guarantee continuity of service by specifying the transmission technique and timing of the message informing that the role which has been changed from the master to the slave to the controller which has previously served as the master has been changed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

100: controller 110: flow table management unit
120: switch interlock processing unit 130: role change processing unit
200: Switch 210: Flow table management unit
220: controller interlock processing unit 230: controller role management unit
240:

Claims (15)

In a software defined networking environment where the switch changes the role of the controller,
Receiving a role change message from a first controller requesting a master authority; And
And changing the first controller to a master controller by sending a role change response message including transaction information of a packet that the switch last processed to the first controller.
How to change the role of the controller. The method according to claim 1,
The role change response message includes:
Further comprising an IP address of a second controller which is an existing master controller,
How to change the role of the controller. The method according to claim 1,
Further comprising setting the second controller as a slave controller by transmitting a status setting message for setting a second controller as a slave controller, which is an existing master controller, to the second controller.
How to change the role of the controller. The method of claim 3,
The status setting message includes:
And the first controller is changed to the switch or the master controller and is transmitted to the second controller.
How to change the role of the controller. The method of claim 4,
The status setting message includes:
Characterized in that the switch comprises transaction information of the last processed packet.
How to change the role of the controller. The method of claim 3,
Wherein the step of setting the second controller as a slave controller comprises:
Wherein the first controller is changed to a master controller and then the status setting message is transmitted to the second controller after a preset time elapses.
How to change the role of the controller. The method of claim 3,
Wherein the step of setting the second controller as a slave controller comprises:
When the second controller transmits a control message to the switch after changing the first controller to the master controller, transmitting the status setting message to the second controller.
How to change the role of the controller. A method of changing a role of a controller performed by a first controller requesting a master authority in a software defined networking environment,
Transmitting a role change message requesting a master right to a switch;
Changing a role to a master controller by receiving a role change response message including transaction information of a packet finally processed by the switch from the switch; And
And setting the second controller as a slave controller by transmitting a status setting message for setting a second controller as a slave controller as an existing master controller to the second controller.
How to change the role of the controller. The method of claim 8,
The role change response message includes:
Further comprising an IP address of a second controller which is an existing master controller,
How to change the role of the controller. The method of claim 8,
The status setting message includes:
And the transaction is transmitted including the transaction information of the last processed packet.
How to change the role of the controller. The method of claim 8,
Receiving packet information to be processed by the switch from the second controller in response to the status setting message; And
Further comprising controlling the switch to process the packet according to packet information to be processed by the switch,
How to change the role of the controller. In a method of changing a role of a controller performed in a second controller which is an existing master controller in a software defined networking environment,
Setting the second controller as a slave controller by receiving a status setting message including transaction information of a packet finally processed by the switch; And
And transmitting the packet information to be processed by the switch to the first controller changed to the master controller in response to the status setting message.
How to change the role of the controller. The method of claim 12,
The status setting message includes:
And the second controller receives the signal from the switch or the first controller.
How to change the role of the controller. The method of claim 12,
The status setting message includes:
Wherein the first controller is changed to a master controller and then received after a predetermined time elapses.
How to change the role of the controller. The method of claim 12,
The status setting message includes:
Wherein the controller is received when the second controller transmits a control message to the switch after the first controller is changed to the master controller.
How to change the role of the controller.

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