KR20140072343A - Method for handling fault in softwate defined networking networks - Google Patents

Abstract

A method for dealing with a software defined networking (SDN) network is disclosed. If the failure is detected, the bypass port information corresponding to the failed port is obtained in the flow table. Then, based on the obtained bypass port information, To perform port switching. Accordingly, it is possible to quickly respond to a failure, thereby ensuring continuity of traffic transmission.

Description

{METHOD FOR HANDLING FAULT IN SOFTWARE DEFINED NETWORKING NETWORKS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a software defined networking (SDN) technology, and more particularly, to an SDN network failure prevention method capable of ensuring continuity of traffic in an SDN network.

Network technology has become a very important infrastructure in businesses, homes and public institutions. However, the current network includes communication devices such as a router or a switch. Such communication devices include complicated protocols and functions, and there are many cases in which characteristics are different according to each manufacturer. .

In order to solve the problems of the network technology described above, a switch or router technology having an open interface has been studied. However, the network technology providing the open interface has been hindered from commercialization due to high price compared to the performance.

OpenFlow technology has emerged to provide an open standard interface to users or developers while addressing costly problems.

The open flow technology separates the packet forwarding function and the control function of the network switch and provides a protocol for communication between the two functions so that the software driven by the external control device can determine the packet path in the switch regardless of the equipment manufacturer do.

An open-flow system includes an open-flow switch and a controller. The open-flow switch and the controller are configured to use a standardized open-flow protocol and configured to perform current network functions using Software Defined Networking Networking, hereinafter abbreviated as SDN) network.

The open-flow switch performs basic switching functions and is composed of a flow table, a secure channel, and an open-flow protocol. The controller creates the flow table inside the switch by the open flow protocol, which includes the ability to register or delete a new flow.

In the open flow system, the key function for the operation of the controller and the open flow switch node is the flow table. The flow table is used to forward packets to a specified port on an open flow node, do.

However, in the conventional open flow system, when a port failure occurs in the open flow switch, the controller recognizes the failure state, sets a port constituting a new path, and updates the flow table corresponding to the set port It took a lot of time to cope with the failure, and the packet was not transmitted during the time of coping with the failure.

In addition, when a failure occurs in one of the nodes constituting the network, there is a problem that the traffic transmission is interrupted during the failure recovery time such as reconfiguring the path and updating the flow table.

An object of the present invention to solve the above problem is to provide a fault handling method of an SDN network that can guarantee continuity of traffic transmission when a fault occurs in an SDN network.

According to another aspect of the present invention, there is provided a method for handling a failure of an SDN network, the method comprising: setting bypass information to be transferred when a failure occurs in a flow table; Obtaining the bypass port information corresponding to the port and performing port switching from the failed port to the bypass port based on the obtained bypass port information.

According to the above-described method for coping with the failure of the SDN network, the flow table set for the port of the open flow switch (or node) and / or the standby port information that can be switched in case of node failure is used, By performing port switching, it is possible to quickly switch the traffic flow, thereby minimizing service interruption time.

In addition, by analyzing the traffic flow in the network at the time of failure, the optimum traffic transmission path is reconfigured and the standby port is updated accordingly, thereby ensuring continuity of traffic transmission in case of a port or node failure, Can be improved.

FIG. 1 is a conceptual diagram for explaining an environment to which a failure coping method of an SDN network according to an embodiment of the present invention is applied.
2 shows an example of port shape information of a node managed by the open flow controller.
FIG. 3 shows a configuration of a flow table of a node in a failure coping method of an SDN network according to an embodiment of the present invention.
FIG. 4 shows a flow table for explaining the contents of change and the contents of execution in the flow table shown in FIG. 3 when a port failure occurs.
FIG. 5 is a flowchart illustrating a method of handling a port failure in the SDN network failure handling method according to an exemplary embodiment of the present invention. Referring to FIG.
FIG. 6 is a flowchart illustrating a method of handling a node failure in a failure handling method of an SDN network according to an exemplary 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.

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 should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

In the failure handling method of the SDN network according to an embodiment of the present invention, a flow table for normal traffic processing includes a standby port capable of switching traffic flow when a failure occurs in a port of an open flow switch, The standby port is set so that the traffic flow can be quickly switched in the event of a failure, and at the same time, the traffic flow in the network is analyzed at the time of failure, and the optimal path is reconfigured to update the standby port in the flow table Thereby ensuring continuity of traffic in the event of port and node failure.

The terms " open flow switch " and " node " used in the following description are used interchangeably.

FIG. 1 is a conceptual diagram for explaining an environment to which a failure coping method of an SDN network according to an embodiment of the present invention is applied, for example, an SDN network is illustrated.

1, an SDN network includes an open flow controller 110 and a plurality of open flow switches 120, 130, 140, 150, and 160 serving as nodes, 120, 130, 140, 150, and 160 communicate with each other using an open flow protocol 180.

The open flow controller 110 creates a flow table in the plurality of open flow switches 120, 130, 140, 150, and 160 by the open flow protocol 180 or performs a function of registering and deleting a new flow .

Each of the open flow switches 120, 130, 140, 150, and 160 performs a basic switching function, and may be configured as an open flow dedicated switch that supports only an open flow and supports the existing L2 and L3 layers It can also be configured as an open-flow general-purpose switch that adds an open-flow function to the switch.

Each of the open flow switches 120, 130, 140, 150, and 160 divides the received packet into flows, processes packets according to the rules defined in the flow table, and transmits the packet to the destination port. Here, the flow may refer to a TCP connection, a specific MAC or IP address, and packets having the same VLAN value.

As shown in FIG. 1, traffic transmission from the transmitting terminal 10 to the receiving terminal 20 is performed by the open flow switch 120 (or the node A), the open flow switch 130 (or the node B), the open flow switch 160 , Or node E). In order to transfer such traffic, the open flow controller 110 previously transmits path information to each open flow switch 120, 130, 160 on the traffic transmission path (path I) (120, 130, and 160) constructs a flow table by receiving path information, and then forwards the traffic to the node based on the flow table to the corresponding node to forward the traffic to the next node.

However, when a failure occurs in the output port of the open flow switch 120 (or the node A) or the open flow switch 130 (or the node B) as illustrated in FIG. 1, a new path (for example, 1), it is necessary to update the flow table to the port that constitutes the path 2).

As shown in FIG. 1, the present invention guarantees continuity of traffic transmission by providing a method for quickly responding to a failure when a port or a specific node of a specific node fails in the SDN network.

2 shows an example of port shape information of a node managed by the open flow controller. FIG. 2 illustrates port shape information of the node A 120 shown in FIG. 1 as an example, and port shape information for other nodes is managed in the same manner.

2, the port configuration information of the node includes node information 210 for identifying nodes, port number 220 configured for each node, bandwidth 230 for each port, current traffic capacity for each port 240, and a node 250 connected to each port. Here, the information on the traffic capacity 240 is received and held in real time in the information transmitted from the node.

The open flow controller selects the optimal path for port reconfiguration or port reconfiguration by performing a traffic engineering process using port configuration information for each node shown in FIG. 2 when a port failure occurs or a node failure occurs.

FIG. 3 shows a flow table configuration of a node in a failure handling method of an SDN network according to an embodiment of the present invention. The configuration of a flow table of a node A in a steady state in which no failure has occurred is shown as an example .

Referring to FIG. 3, the flow table mainly includes three pieces of important information.

That is, the flow table includes packet header information (rule) 310 defining a flow, operation information (action) 320 indicating how to process the packet, and statistical information (statistics) 330 for each flow.

The information elements included in the packet header information, the operation information, and the statistical information described above correspond to the content of the flow table defined by ONF (Open Networking Foundation), which is a standardization organization, and therefore detailed description will be omitted. In one embodiment of the present invention, standby port information 340 designating a port for performing packet forwarding when a failure occurs is added to three main information as described above, and a flow table is defined and used. Here, the standby port means a bypass port for bypassing the traffic transmission path when a failure occurs.

FIG. 4 shows a flow table for explaining the contents of change and the contents of execution in the flow table shown in FIG. 3 when a port failure occurs. For example, a failure occurs in the port 1 of the node A. FIG.

Referring to FIG. 4, when the node A recognizes that a failure has occurred in the port 1, the node A directly transmits the port 1 item 421 corresponding to the action field 420 of the flow table to a predetermined value (for example, ff).

That is, in the packet forwarding function, when the specific item 421 of the action field 420 is a predetermined value (for example, ff), the port switching is performed to the port specified in the corresponding item 441 of the standby port field 440 And forwards the packet to the switched port. Here, when the failed port is recovered, the switched port is switched to the original port using the flow table information per node managed by the open flow controller.

For example, as shown in FIG. 4, when a failure occurs in the port 1 and a predetermined value ff is recorded in the corresponding item 421 of the action field 420, the port 1 in which the failure occurs corresponds to the standby port field 440 The port is switched to Port 2, which is the port designated in the item 441, and the packet is delivered through the switched port 2. When the failure of the port 1 is recovered, in accordance with the node-specific flow table information managed by the open flow controller, To the original state.

FIG. 5 is a flowchart illustrating a method of handling a port failure in the SDN network failure handling method according to an exemplary embodiment of the present invention. Referring to FIG.

5, the traffic propagation path includes a node A 520, a node B 530, a node C 540, a node D 550, And a node E (560), and a port failure occurs in the node A (520).

5, first, the node A 520 detects a failure of a specific port (S501). Then, the node A 520 transmits an item corresponding to the failed port among the action fields of the flow table managed by the node A 520 to a predetermined value (for example, ff), and then performs port switching to the standby port by referring to the standby port information corresponding to the failed port (S503). For example, when a failure occurs in a specific port, the node A 520 changes the corresponding contents of the flow table and performs port switching with reference to the standby port information set in the flow table, as described with reference to FIGS. 3 and 4 .

Then, the node A 520 reports the port fault by transmitting the port fault information to the open flow controller 510 (S505). In an embodiment of the present invention, when a specific node detects a port failure, the failure port is first switched to the standby port, and then the port fault report is performed to the open flow controller, thereby minimizing the delay of the traffic flow.

When the open flow controller 510 receives the port failure report from the node A 520, the open flow controller 510 selects an optimal standby port by referring to the port configuration information of the node A 520 (S507) And requests a flow table update according to the port setting (S511).

Upon receiving the flow table update request from the open flow controller 510, the node A 520 updates the standby port information of the flow table based on the received flow table update request information (S511). Here, the standby port that the node A 520 has transferred in step S503 and the standby port that the open flow controller 510 requested to update may be the same or different from each other. If the standby port to which the node A has switched is different from the standby port to which the open flow controller has requested to be updated, the node A can perform port switching again to the standby port for which the open flow controller has requested to be updated.

In the embodiment of the present invention, although the node A has performed the port switching to the standby port at the time when the node A recognizes occurrence of the port failure, the open flow controller requests the update of the standby port information again, So that the reliability of the node function can be improved.

Thereafter, the open flow controller 510 performs a traffic engineering process for analyzing whether the port switching performed according to the port failure of the node A 510 affects traffic flow to other nodes on the traffic transmission path, To the node B 530, the node C 540, the node D 550, and the node E 560 according to the control signal from the node B 530 (S513). That is, the open flow controller 510 requests update of the flow table to each node constituting the traffic transmission path according to the result of the traffic engineering, and each node that receives the update updates the flow table (S515).

On the other hand, when the port failure occurring in the node A is restored, the flow table for each node managed by the open flow controller is restored to its original state.

FIG. 6 is a flowchart illustrating a method of handling a node failure in a failure handling method of an SDN network according to an exemplary embodiment of the present invention.

In Figure 6, the traffic delivery paths are shown as node A 620, node B 630, node C 640, node D 650, And a node E (660), and illustrates a processing method when a failure occurs in the Node B (630).

6, when a failure occurs in the node B 630 during the traffic transmission, the open flow controller 610 detects a failure of the node B 630 (S601) A node A 620, a node C 640, a node D 650, and a node D 650 that instructs the ports A and B To the node E 660 (S603).

Node A 620, node C 640, node D 650, The node E 660 performs port switching to the standby port corresponding to the port corresponding to the port switching request received from the open flow controller 610 (S605). Here, the standby port information of the flow table owned by each of the nodes 620, 640, 650, and 660 is information set in advance as illustrated in FIGS. 3 and 4. In the failure coping method according to an embodiment of the present invention, By using the preset standby port information, the port switching can be performed quickly when a node failure occurs, thereby ensuring continuity of traffic transmission.

Then, the open flow controller 610 performs a traffic engineering process for setting an optimal bypass route due to the failure of the node B 630 based on the port configuration information of each node as illustrated in FIG. 2, The nodes 620, 640, 650, and 660 request the update of the standby port to each of the nodes 620, 640, 650, and 660 according to the result (S607) And updates the standby port information (S609).

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

10: transmitting terminal
20: receiving terminal
110: Open flow controller
120, 130, 140, 150, 160: Open flow switch
180: Open Flow Protocol
510, 610: Open flow controller
520, 620: Node A
530, 630: Node B
540, 640: Node C
550, 650: node D
560, 660: Node E

Claims (1)

In a failure handling method performed at a node of a software defined networking network,
Setting bypass information to be transferred when a failure occurs in the flow table;
Acquiring bypass information corresponding to a failed port in the flow table when a failure is detected; And
And performing port switching from the failed port to the bypass port based on the acquired bypass port information.

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