KR20150052773A - Communication method in software defined network using hierachical structure and system thereof - Google Patents

Abstract

Disclosed are a communication method in a software defined network using a hierarchical structure and a system thereof. A communication method in a software defined network according to an embodiment of the present invention includes a step of separating a transmission plane from a control plane; a step of hierarchically dividing the control plan into low-rank controllers and a high-rank controller which manages the low-rank controllers, and a step of controlling communication between unit networks or one or more networks by using the hierarchical structure of the control plane.

Description

[0001] The present invention relates to a communication method in a software defined network using a hierarchical structure,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to network communication and management technology, and more particularly to software defined network technology.

There is a technology for separately configuring a network control plane in a transport plane of the network to flexibly configure the network. Software Defined Network (SDN) technology separates the transmission plane and the control plane of a network and allows the transmission plane to query the control plane for all the decisions needed for packet transmission, Installed software allows centralized control of network configuration and packet flow. In SDN, the control plane is usually called the SDN controller.

By concentrating the control plane of the network on one controller, it is possible to control the packet transmission process through software. However, the scalability problem arises because the control functions of all transmission equipment are concentrated on one controller. When the size of a network grows, all the transmission equipment communicates with one controller, so the amount of traffic that the controller needs to control increases in proportion to the network scale. In addition, if the transmission network is controlled by a single controller, it is difficult for an administrator to correctly understand and manage the shape of a complex network in a large network.

According to one embodiment, a communication method and a system in a software defined network using a hierarchical structure for facilitating network control and management are proposed.

A communication method in a software defined network according to an embodiment includes separating a transmission plane and a control plane and hierarchically separating the control plane into an upper controller that integrally manages a plurality of sub controllers and a plurality of sub controllers And controlling the communication between the unit networks or the at least one unit network using the hierarchical structure of the control plane.

The software defined network system according to another embodiment includes a sub controller that manages each unit network for each unit network and a host controller that integrally manages a plurality of sub controllers, And provides it to the host controller, the host controller controls the abstraction unit network communication.

According to one embodiment, the control plane is hierarchically separated into an upper controller and a lower controller, and the upper controller controls only inter-network communication instead of controlling the entire network. That is, each sub controller abstracts the unit network managed by itself and provides it to the host controller, and the host controller controls the abstracted unit network communication. Accordingly, the upper controller can control the entire network without knowing the inner configuration of the unit network managed by each lower controller, thereby reducing the level of complexity required for network control.

Furthermore, by dividing a large-scale network into unit network units, allocating separate controllers, and linking them in a hierarchical manner, the number of transmission devices that one controller should take on can be reduced, thereby solving the scalability problem of the network. Further, unitary networks may be interworked with any other network, for example, an IP network.

1 is a structure diagram of an SDN having a hierarchical structure according to an embodiment of the present invention;
2 is a detailed structural diagram of a unit network according to an embodiment of the present invention;
3 is a network structure diagram for inter-unit network communication using a hierarchical structure in an SDN according to an embodiment of the present invention;
4 is a network structure diagram for inter-unit network communication using a hierarchical structure in an SDN according to another embodiment of the present invention.
5 is a network structure diagram for inter-unit network communication using an IP network in SDN according to an embodiment of the present invention;
6 is a network structure diagram for communication between IP networks over a unit network in an SDN according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention of the user, the operator, or the custom. Therefore, the definition should be based on the contents throughout this specification.

1 is a structural diagram of a software defined network having a hierarchical structure according to an embodiment of the present invention.

Referring to FIG. 1, a Software Defined Network (SDN) 1 according to an embodiment includes three unit networks 10a, 10b, and 10c. Each unit network 10a, 10b, 10c is a network in which a control plane and a transmission plane are separated. The control plane in each unit network 10a, 10b, 10c includes a plurality of transmission devices and at least one router, and the transmission plane includes a controller.

For example, the transmission plane of the first unit network 10a includes a first lower controller 12a that manages a plurality of first transmission apparatuses 100, 102, 104, and 106, and the transmission plane of the second unit network 10b includes a plurality The transmission plane of the third unit network 10c includes a third lower controller 12b that manages a plurality of third transmission apparatuses 120, 122, 124, 126, and a second lower controller 12b that manages the second transmission apparatuses 110, 12c. Each of the lower controllers 12a, 12b and 12c is connected to the upper controller 14 so that the upper controller 14 manages and controls the lower controllers 12a, 12b and 12c.

Routers connect between unit networks. For example, the first router 16a connects the first unit network 10a and the second unit network 10b, and the second router 16b connects the second unit network 10b and the third unit network 10b. And the third router 16c connects the third unit network 10c and the first unit network 10a.

Referring to FIG. 1, the control plane is hierarchically separated into an upper controller 14 and a plurality of lower controllers 12a, 12b, and 12c. Then, the upper controller 14 controls only the inter-unit network communication instead of controlling the entire network 1. [ That is, when each of the lower controllers 12a, 12b, and 12c abstraction of the unit networks 10a, 10b, and 10c managed by the lower controllers 12a, 12b, and 12c and provides them to the upper controller 14, And controls inter-network communication. Accordingly, the host controller 14 can control the entire network without knowing the internal configuration of the unit networks 10a, 10b, and 10c managed by the respective sub controllers 12a, 12b, and 12c, The level of complexity is reduced.

Although FIG. 1 shows a controller relationship having a hierarchy of upper and lower two levels, this relationship can be extended to an arbitrary scale. Although FIG. 1 shows three unit networks, the number of unit networks and the number of elements constituting the unit network can also be reduced or expanded.

2 is a detailed structural view of a unit network according to an embodiment of the present invention.

2, one unit network 20 includes a plurality of transmission apparatuses 200, 202, ..., and 216 connected in an arbitrary topology, and a plurality of unit networks 20, Routers 220, 222, 224, and 226, and a controller 230. Routers can use existing IP routers without modification. Alternatively, the router can be implemented by controlling the transmission device with a controller. For example, a transmitting apparatus can control a transmitting apparatus through a controller to use a transmitting apparatus as an IP router to process a specific packet as an IP router. Although not shown in FIG. 2, various terminals, for example, computers, are connected to each transmission device.

A transmitting apparatus included in one unit network queries a controller to which port a packet is to be transmitted, in order to correctly transmit a packet transmitted and received between terminals in the same unit network to the corresponding terminal. In order to respond to the query, the controller analyzes the protocol packet operating in the link layer, and notifies the link layer address information, the IP address information, and the transmission apparatus information of the terminal, Device link linkability information and the like can be acquired in advance. Through the above-described information, the controller can acquire the connection shape in the unit network, that is, the topology information. Further, the controller may preliminarily input the IP bands of the terminals existing in one unit network. In addition, the IP address of the router transmitting the packet to the external unit network, the link layer address information, and the like can be input to the controller in advance. The above-mentioned preliminary procedure is summarized as follows.

[Preliminary Procedure 1]

For communication between unit networks or a unit network, the lower controller of the unit network according to an embodiment transmits the following information to the upper controller using the inter-controller interworking protocol. That is, the lower controller transmits the IP band information of the terminals included in the unit network to the upper controller. The IP bandwidth information can be briefly expressed as classless inter-domain routing (CIDR) or the like. In addition, the lower controller transmits the IP address and the MAC address of the router, which is information on the router connected to the external unit network, to the host controller. Transmission of the above-described information may be periodically performed. The above-described information is used in a terminal-to-terminal communication process through a plurality of unit networks. The upper controller can grasp the connectivity between the unit networks using the above-described information, and can grasp the IP band of the terminal installed in each unit network.

[Preliminary Procedure 2]

The controller of the unit network according to an embodiment transmits the following information to a router connected to a unit network controlled by the controller of the unit network. That is, information on which IP band terminals are connected to the corresponding routers through the transmission devices is transmitted. The above information is used to enable each router to transmit and receive information about the IP bandwidth of the terminals installed in the entire network through a conventional IP routing protocol such as OSPF (open shortest path first) So that the packets can be correctly transmitted to the destination.

Various embodiments of the present invention will be described below with reference to Figs. 3 to 6, based on the network environment in which the foregoing pre-procedures are satisfied. In order to facilitate understanding of the present invention, it is assumed that a transmitting terminal and a receiving terminal communicate via several unit networks.

3 is a network structure diagram for inter-unit network communication using a hierarchical structure in SDN according to an embodiment of the present invention.

[Procedure 1-1]

3, when the transmitting terminal 39a of the first unit network 30a desires to communicate with the receiving terminal 39b of the second unit network 30b, the transmitting terminal 39a is connected to the receiving terminal 39b, Lt; RTI ID = 0.0 > IP < / RTI > In this process, an ARP REQUEST message is generated. When the first lower controller 32a receives a query message inquiring how to process the packet, from the transmission apparatus of the first unit network 30a, And checks whether the IP address of the terminal 39b is within the first unit network 30a. If there is no check result, the first lower controller 32a transmits a query message inquiring how to process the packet to the upper controller 34 in the upper layer.

Since the host controller 34 already knows the fact that the receiving terminal 39b exists in the second unit network 30b through the [Preliminary Procedure 1], the host controller 34 judges that the router A 36 connected to the second unit network 30b And informs the transmitting apparatus that the link layer address (MAC address) is included in the ARP RESPONSE and returned to the transmitting terminal 39a. As a result, in order to transmit a packet to the IP address of the receiving terminal 39b, the transmitting terminal 39a first learns to transmit the packet to the MAC address of the router A 36, A 36, and transmits the packet.

[Procedure 1-2]

When the packet transmitted from the transmitting terminal 39a reaches the router A 36, the router A 36 replaces the sender MAC address with the MAC address of the router A 36. However, since the router A 36 does not know the MAC address of the destination receiving terminal 39b, the router A 36 transmits an ARP REQUEST packet including the IP address of the destination to the transmitting apparatus of the second unit network 30b. The second lower controller 32b receiving the packet through the transmission apparatus confirms that the IP address of the destination is an IP address in the same network, distributes the ARP REQUEST packet in the network, and transmits the packet to the destination receiving terminal 39b To the transmitting apparatus of the second unit network 30b, and the transmitting apparatus transmits the packet to the receiving terminal 39b in accordance with the instruction. As a result, the destination receiving terminal 39b returns the ARP RESPONSE and informs the router A 36 of the MAC address of the receiving terminal 39b corresponding to the IP address. As a result, the router A 36 correctly records the destination MAC address of the IP packet to be transmitted, and transmits the packet. As a result, the packet arrives at the destination receiving terminal 39b.

[Assumption 1]

Controlling packet transmission within a unit network through a controller is a generalized technique in SDN. In other words, the transmission of a packet from the router A 36 to the receiving terminal 39b is performed by using a well-known technique, and thus a detailed description thereof will be omitted.

[Assumption 2]

It is assumed that each unit network and the controller that manages the unit network already have a function of transmitting routing protocol packets such as OSPF to all routers connected to the unit network.

In the meantime, the present invention can be similarly applied to a situation in which an upper controller is connected to a lower controller of another upper controller by expanding in the above embodiment with reference to FIG.

4 is a network structure diagram for inter-unit network communication using a hierarchical structure in an SDN according to another embodiment of the present invention.

[Procedure 2-1]

Referring to FIG. 4, there are four unit networks 40a, 40b, 40c and 40d, and a transmitting terminal 49a included in the first unit network 40a is connected to a fourth unit network 40d It is assumed that a packet is transmitted to the terminal 49b. When the transmitting terminal 49a transmits an ARP REQUEST packet to obtain the MAC address of the receiving terminal 49b using the IP address of the receiving terminal 49b, the transmitting apparatus receiving the packet transmits the ARP request packet to the first unit network 40a, Controller 42a assigned to the first lower controller 42a. The first lower controller 42a confirms that the received IP address is not an IP address in the first unit network 40a and does not know where to transmit the packet, and thus the first lower controller 42a is made of the first upper controller 44a. Upon receiving the inquiry message, the first upper controller 44a confirms that the received IP address is not an IP address in the first unit network 40a and the second unit network 40b, And.

Since the top-level controller 46 knows that the IP address received through [Preliminary Procedure 1] is in the fourth unit network 40d managed by the second upper controller 44b, the IP address of the router B 48b And returns the MAC address to the first upper controller 44a. The first upper controller 44a receiving the IP address and the MAC address of the router B 48b notifies the router A 48a that a packet must be transmitted to the router B 48b in order to transmit the packet to the router B 48b 1], the IP address and the MAC address of the router A 48a are returned to the first lower controller 42a. The first lower controller 42a transmits an ARP REPLY including the IP address and the MAC address of the router A 48a to the transmitting terminal 49a and the transmitting terminal 49a transmits the ARP REPLY including the IP address and the MAC address of the receiving terminal 49b to the router A 48a. Lt; RTI ID = 0.0 > IP < / RTI >

[Procedure 2-2]

When the IP packet transmitted from the transmitting terminal 49a reaches the router A 48a, the MAC address of the sender is changed to the MAC address of the router A. When the router A 48a does not know the MAC address of the router B 48b to be transmitted to the destination IP, it transmits an ARP REQUEST message including the destination IP address to the transmitting apparatus of the second unit network 40b , This message is transmitted to the highest level controller 46 which knows the MAC address of the router B 48b through the second lower controller 40b and the first upper controller 44a. The top controller 46 confirms that the packet should be transmitted to the router B 48b and the router A 48a changes the destination MAC address of the packet to be transmitted to the MAC address of the router B 48b And transmits the IP packet to the router B (48b).

[Proposition 2] is correctly performed and [Assumption 2] is established, router A 48a determines that the next router to go to the final destination is router B 48b and the MAC address of router B 48b In this case, [Procedure 2-2] described above may be omitted.

[Procedure 2-3]

[Procedure 2-2] is continuously repeated so that the packet enters the fourth unit network 40d in which the receiving terminal 49b is located, and then the packet transfer procedure in the fourth unit network 40d is performed [Procedure 1- 2].

The embodiments described above with reference to FIG. 3 and FIG. 4 may be applied to embodiments in a state in which a process of processing an ARP REQUEST packet is assumed, or in other types of packet processing, This technology can be applied to the extent possible.

On the other hand, the present invention can be applied even if another predetermined IP network exists between each unit network. For example, even if another predetermined IP network exists between unit networks as shown in FIG. 5 to be described later, it is applied without any problem. This is because an IP router at the boundary of a unit network handles packet transmission to the corresponding IP network section.

5 is a network structure diagram for unit network communication using an IP network in an SDN according to an embodiment of the present invention.

Referring to FIG. 5, it is possible for terminals of each unit network to communicate through an IP network. The upper controller 54 understands the IP band of the first unit network 50a through the first lower controller 52a and the IP band of the second unit network 50b through the second lower controller 52b I understand. Information indicating that the router A 56a and the router B 56b are connected through the IP network 58 may be manually input to the host controller 54 or the router A 56a and the router B 56b may transmit / The routing protocol packet may be analyzed and collected. That is, since the host controller 54 can collect and manage the shape of the entire network, it is understood that the packet transmitted from the transmitting terminal 59a to the receiving terminal 59b must pass through the router A 56a. Therefore, when the transmitting terminal 59a transmits the packet to the router A 56a, the transmission to the router B 56b is performed according to the procedure calculated through the existing IP routing protocol.

6 is a network structure diagram for communication between IP networks over a unit network in an SDN according to an embodiment of the present invention.

Referring to FIG. 6, it is possible for each IP network to communicate over one or more unit networks. For example, it is possible for each IP network 66a, 66b to communicate over one or more unit networks 60 as shown in Fig. Since the router A 64a and the router B 64b understand the entire network configuration including the unit network 60 through the [Preliminary Procedure 2], the packet from the transmitting terminal 69a to the receiving terminal 69b Can be safely delivered. This procedure corresponds to the packet forwarding procedure in the existing IP network. In FIG. 6, reference numeral 62 denotes a controller for managing the unit network 60.

Although the IP technology has been assumed and described with reference to the above-described drawings, it is possible to similarly apply the contents of the present invention to any network protocol.

The embodiments of the present invention have been described above. 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 by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention of the user, the operator, or the custom. Therefore, the definition should be based on the contents throughout this specification.

Claims (18)

A method of communication in a software defined network,
Separating the transmission plane and the control plane;
Hierarchically separating the control plane into an upper controller that integrally manages a plurality of lower controllers and a plurality of lower controllers; And
Controlling communication through a unit network or at least one unit network using the hierarchical structure of the control plane;
Wherein the software defined network comprises: 2. The method of claim 1, wherein controlling the communication comprises:
Abstracting the unit networks managed by each lower controller and providing them to the upper controller; And
Controlling an inter-unit network communication of the abstract controller;
Wherein the software defined network comprises: The method of claim 1, wherein the communication method in the software defined network
The lower controller transmits the IP band information of at least one terminal included in the first unit network managed by itself and the IP address and link layer address information of the router connecting the first unit network and the second unit network to the upper controller Transmitting;
Further comprising a pre-processing step comprising the steps of: The method of claim 1, wherein the communication method in the software defined network
The sub-controller transmitting IP band information of at least one terminal of the first unit network managed by the sub-controller to a router connecting the first unit network and the second unit network;
Further comprising a pre-processing step comprising the steps of: The method of claim 1, wherein the software defined network
A first router connected to the first IP network; a second router connected to the first IP network; and a second router connected to the first router and the second router, At least one unit network connecting a second router,
Wherein the controller for managing the at least one unit network transmits a packet to a receiving terminal connected to the second IP network via the at least one unit network by a transmitting terminal connected to the first IP network, Transmitting IP bandwidth information of terminals of the unit network to a router connected to the router;
Further comprising a pre-processing step comprising the steps of: The method of claim 1, wherein the software defined network
A first unit network including a transmitting terminal, a second unit network including a receiving terminal, a router connecting the first unit network and the second unit network, and a second unit network including a first sub- A second controller for managing the second unit network; and a higher controller for managing the first lower controller and the second lower controller,
The step of controlling the communication
Transmitting a query message including the IP address of the receiving terminal to the first lower controller so that the transmitting terminal included in the first unit network transmits a packet to the receiving terminal included in the second unit network; And
The first lower controller checks whether the IP address of the receiving terminal is in the first unit network, and transmits a message of a material to the upper controller if the first controller is not present;
Wherein the software defined network comprises: 7. The method of claim 6, wherein controlling the communication further comprises:
Confirming that the host controller having received the message of the material has the receiving terminal in the second unit network and returning the link layer address of the router connecting the first unit network and the second unit network to the transmitting terminal;
The transmitting terminal transmitting a packet to a link layer address of the router; And
Transmitting a packet from the router to the receiving terminal;
Further comprising the steps of: The method according to claim 6,
Wherein the router connecting the first unit network and the second unit network includes a first router and a second router, the first router and the second router are connected via an IP network,
The communication method in the software defined network
Analyzing a packet transmitted between the first router and the second router to collect IP network information or manually input IP network information;
Further comprising the steps of: The method of claim 1, wherein the software defined network
A first unit network including a transmitting terminal, a second unit network, a third unit network, a fourth unit network including a receiving terminal, and a first unit network including a first unit network and a second unit network, A second router for connecting the second unit network and the third unit network; a first sub controller for managing the first unit network; a second sub controller for managing the second unit network; A first lower controller for managing the first lower controller and the second lower controller; a third lower controller for managing the third unit network; a fourth lower controller for managing the fourth unit network; A third upper controller for managing the third lower controller and the fourth lower controller, and a second upper controller for managing the first upper controller and the second upper controller Including the above controller,
The step of controlling the communication
Transmitting a query message including the IP address of the receiving terminal to the first lower controller so that the transmitting terminal included in the first unit network transmits a packet to the receiving terminal included in the fourth unit network;
The first lower controller checks whether the IP address of the receiving terminal is present in the first unit network and transmits a message of material to the first upper controller if it is not present; And
The first upper controller checks whether the IP address of the receiving terminal is in the second unit network and transmits a message of a material to the highest controller if it is not present;
Wherein the software defined network comprises: 10. The method of claim 9, wherein controlling the communication further comprises:
The controller determines that the IP address of the receiving terminal is present in the fourth unit network and transmits the link layer address of the second router connecting the second network and the third network to the first upper controller ;
Returning a link layer address of a first router connecting the first network and the second network to the transmitting terminal;
The transmitting terminal transmitting a packet to a link layer address of the first router;
The first router sending a packet to the second router using the link layer address of the second router; And
The second router transmitting a packet to the receiving terminal;
Wherein the software defined network comprises: 11. The method of claim 10, wherein controlling the communication further comprises:
If the first router does not know the link-layer address of the second router, the first router queries the second sub-controller via the transmission device for the link-layer address of the second router and the second sub- Obtaining a link-layer address of the second router from the top-level controller, the first top-controller being made of the first top controller and the first top controller being made of the top-level controller;
Further comprising the steps of: In a software defined network system,
A sub-controller for managing each unit network by unit network; And
A parent controller which integrally manages a plurality of sub controllers; / RTI >
Wherein each sub controller abstracts the unit network managed by the sub controller and provides the unit network to the upper controller, and controls the abstract unit network communication between the upper controller. 13. The system of claim 12, wherein the software defined network system
A first unit network including a transmitting terminal, a second unit network including a receiving terminal, a router connecting the first unit network and the second unit network, and a second unit network including a first sub- A second controller for managing the second unit network; and a higher controller for managing the first lower controller and the second lower controller. 14. The method of claim 13,
The transmitting terminal included in the first unit network transmits a query message including the IP address of the receiving terminal to the first lower controller to transmit a packet to the receiving terminal included in the second unit network,
Wherein the first lower controller checks whether the IP address of the receiving terminal is present in the first unit network, and transmits the message of the material to the upper controller if the IP address is not present in the first unit network. 14. The system of claim 13, wherein the software defined network system
Wherein the router connecting the first unit network and the second unit network includes a first router and a second router, the first router and the second router are connected via an IP network,
Wherein the transmitting terminal and the receiving terminal communicate between the first unit network and the second unit network via the IP network. 13. The system of claim 12, wherein the software defined network system
A first unit network including a transmitting terminal, a second unit network, a third unit network, a fourth unit network including a receiving terminal, and a first unit network including a first unit network and a second unit network, A second router for connecting the second unit network and the third unit network; a first sub controller for managing the first unit network; a second sub controller for managing the second unit network; A first lower controller for managing the first lower controller and the second lower controller; a third lower controller for managing the third unit network; a fourth lower controller for managing the fourth unit network; A third upper controller for managing the third lower controller and the fourth lower controller, and a second upper controller for managing the first upper controller and the second upper controller The software defined network system comprising the above controller. 17. The method of claim 16,
The transmitting terminal included in the first unit network transmits a query message including the IP address of the receiving terminal to the first lower controller to transmit a packet to the receiving terminal included in the fourth unit network,
The first lower controller checks whether the IP address of the receiving terminal is present in the first unit network and transmits a message of material to the first upper controller if it is not present,
Wherein the first upper controller confirms whether the IP address of the receiving terminal is present in the second unit network, and transmits the message of the material to the uppermost controller if the IP address is not present in the second unit network. 13. The system of claim 12, wherein the software defined network system
A first router connected to the first IP network; a second router connected to the first IP network; and a second router connected to the first router and the second router, At least one unit network connecting a second router,
Wherein the transmitting terminal connected to the first IP network communicates with the receiving terminal connected to the second IP network through the at least one unit network.

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