KR101491948B1 - Method and apparatus for distributed mobility management - Google Patents

Abstract

The present invention relates to a method to manage mobility in a software-defined networking environment. According to an embodiment of the present invention, a mobility management method may include the steps of: receiving, from a switch, a location registration message of a mobile node currently connected to the switch; maintaining a database which stores identification information of the mobile node and location information of the mobile node mapped to the identification information; receiving, from a transmission node, a request for data transmission to the mobile node; determining a cross switch, wherein the cross switch is located farthest from the transmission node among the switches located in a path wherein a first virtual path from the transmission node to a previous switch (PS) overlaps a second virtual path from the transmission node to a next switch (NS); setting a data transmission path from a switch to which the transmission node is connected to a switch to which the mobile node is currently connected in consideration of at least one of a hop number and a traffic situation, the data transmission path including the cross switch; and transferring the data transmission path to all the switches located in the data transmission path.

Description

[0001] METHOD AND APPARATUS FOR DISTRIBUTED MOBILITY MANAGEMENT [0002]

The present invention relates to a mobility management technique and apparatus, and more particularly, to a distributed mobility management method in a software defined networking environment.

In order to solve the problem of mobile traffic explosion, which is becoming a recent issue, a standardization organization is discussing ways to provide mobility management on mobile Internet in a distributed manner. In the distributed mobility management technique, instead of using the mobility management server located in the core network, it is possible to reduce the amount of data or control packets flowing into the core network by distributing mobility management in a switch to which the terminal is connected.

Distributed mobility management techniques are divided into a fully distributed method and a partially distributed method. A fully distributed approach manages both the control plane and the data plane in a distributed manner, while the partially distributed approach manages control functions for mobility management in a centralized manner and only distributes data in a distributed manner . Distributed hashing table schemes and multicast schemes are the perfect distributed schemes. In this way, the switch directly manages / shares the location of the mobile node (MN) to deliver the data packet to the MN, and when a handoff occurs, tunneling to the switch from the previous switch It uses a method of delivering packets. While a fully distributed approach has the advantage of distributing control traffic, the overlay implementation and management of switches is complex. On the other hand, in a partial distributed manner (e.g., LIST-TREE), the location information is maintained through a separate central mapping server and only the data packets are distributedly processed. Such a partial distributed method can be preferred in terms of a network operator because a centralized location management system exists to easily maintain a switch or a router and can easily manage charges and the like. A related prior art document is Korean Patent No. 10-1290312.

In the current distributed mobility management technique, when a handoff occurs, the packet is continuously transmitted through the tunnel between the pre-movement switch (PS, Previous Switch) and the post-movement switch (NS, Next Switch). However, if handoff occurs frequently due to a lot of movement of the MN, the tunneling increases and the data transmission path becomes longer, and local traffic continues to be generated in the previous switches. Delay jitter, which occurs when a session is disconnected, lowers the QoS of the MN, although it may be an alternative to optimize the path by disconnecting the tunnel and receiving data directly from the current switch. This delay jitter occurs because the delay between the last packet received from the switch before the movement and the n + 1th packet received from the switch after the movement becomes longer.

On the other hand, Software Defined Networking (SDN) is a network that supports routing by separating the control plane and the data plane from the existing network. Unlike conventional routers that forward packets through routing algorithms, controllers in the SDN manage the network topology and traffic in a centralized manner.

Therefore, the present invention proposes a technology and apparatus capable of supporting mobility management in a software defined networking environment.

It is an object of the present invention to provide a method and apparatus for supporting mobility management in a software defined networking environment so that data can be transmitted through an optimal path even after a Mobile Node (MN) moves.

According to an aspect of the present invention, there is provided a mobility management method in a software defined networking environment, the method comprising: receiving a location registration message of a mobile node currently connected to the switch from a switch; Maintaining a database storing identification information of the mobile node and location information of the mobile node mapped to the identification information; Receiving a data transmission request from a transmitting node to the mobile node; Determining a crossover switch (CS), the crossover switch including a first virtual path from the transmitting node to a previous switch (PS, Previous Switch), a second virtual path from the transmitting node to the next switch (NS, Next Switch) 2 switches located in the path where the virtual paths overlap, the switch being located farthest from the transmission node; Setting a data transmission path from a switch to which the transmission node is connected to a switch to which the mobile node is currently connected, considering the at least one of the number of hops and the traffic situation so that the intersection switch is included; And transferring the data transmission path to all switches located on the data transmission path.

According to an aspect of the present invention, there is provided a mobility management apparatus connected to a plurality of switches in a software defined networking environment, the mobility management apparatus comprising: a switch for receiving a location registration message of a mobile node currently connected to the switch, A mobile node receives a data transfer request from a node to the mobile node, determines a crossing switch, includes the crossing switch, and determines at least one of a hop count and a traffic situation, An SDN controller for setting up a data transmission path to a connected switch and transmitting the data transmission path to all switches located in the data transmission path, the crossover switch being connected to the transmission node and a previous switch The first virtual path and the transmission node A switch located farthest from the transmitting node among switches located in a path where the second virtual path overlaps the NS switch; And a location management server that maintains a database storing identification information of the mobile node and location information of the mobile node mapped to the identification information.

The mobility management method and apparatus according to an embodiment of the present invention can optimize a data transmission path when a handoff occurs in a software defined networking environment.

In addition, according to an embodiment of the present invention, it is possible to prevent a packet loss and at the same time to minimize packet transmission cost and delay jitter.

1 is a diagram illustrating a system for performing mobility management techniques in accordance with an embodiment of the present invention.
FIG. 2 is a diagram for explaining a location registration process among mobility management techniques according to an embodiment of the present invention.
FIG. 3 is a diagram for explaining a packet transfer process among mobility management techniques according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating a comparison between a handoff procedure and an existing handoff procedure according to an embodiment of the present invention. Referring to FIG.
5 is a flow diagram illustrating a mobility management technique in accordance with an embodiment of the present invention.

Hereinafter, a mobility management technique and apparatus according to an embodiment of the present invention will be described with reference to the drawings.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In this specification, the terms "comprising ", or" comprising ", etc. should not be construed as necessarily including the various elements or steps described in the specification, Or may be further comprised of additional components or steps.

Hereinafter, a method of processing data by providing mobility management in a distributed manner in a Software Defined Networking (SDN) environment will be described.

1 is a diagram illustrating a system for performing mobility management techniques in accordance with an embodiment of the present invention.

As shown in the figure, the mobility management apparatus 100 includes an SDN controller 110 and a location management server 120. The mobility management apparatus 100 is connected to a plurality of switches. The MN represents a mobile node, and each switch is an SDN switch. The SDN controller 110 is responsible for routing the switch. According to an embodiment of the present invention, each switch can continuously update information on the MNs connected thereto with the location management server 120 via the SDN controller 110. The SDN controller 110 manages location information of each MN.

In this specification, when the MN moves between the switches, the former switch is referred to as a previous switch (PS), and the moved switch is referred to as a next switch (Next Switch (NS)). In addition, CS (Crossover switch) means an intersection switch and CN (Correspondent Node) means a transmitting node. CS is defined as a switch located at the farthest position from the transmission node among the switches located on the overlapping path when calculating the optimal virtual path from the CN to PS and NS respectively. The optimal path may be set considering at least one of a hop count and a traffic situation. For example, a path with the smallest number of hops or the lowest latency depending on traffic may be the optimal path. The optimal path may be determined according to the policy of the SDN controller 110.

FIG. 2 is a diagram for explaining a location registration process among mobility management techniques according to an embodiment of the present invention.

When the MN is connected to the switch, the switch transmits a location update (LU) message to the SDN controller 110, and the SDN controller 110 transmits a location update (LU) message between the ID of the corresponding MN and the IP address The mapping information can be maintained in the database of the location management server 120. The SDN controller 110 may then respond to the switch through a Location Acknowledge (LACK) message.

For example, when the mobile node moves (S210) and the connected switch (NS) is changed, the MN transmits location update (LU) message to the SDN controller 110 to perform location registration (S220) . The SDN controller 110 may update the database (not shown) of the location management server 120 by registering or modifying the mapping information between the ID of the corresponding MN and the IP address in the NS (S230). When the update is completed, the SDN controller 110 responds to the MN through a Location Acknowledge (LACK) message (S240).

FIG. 3 is a diagram for explaining a packet transfer process among mobility management techniques according to an embodiment of the present invention. FIG. 3 illustrates a packet delivery process when the CN transmits data to the MN.

First, the CN can forward a packet to be transmitted to the MN through a switch (Switch 1) to which the CN is connected (S310). The switch 1 may request the location information of the MN while transmitting the first packet among the packets to be transmitted to the MN, to the SDN controller 110 (S320).

The SDN controller 110 sets an optimal path from the switch 1 of the CN to the switch 5 currently connected to the MN by using the database of the location management server 120 in which the location information of the MN is recorded, It may transmit a packet transmission path (i.e., a data transmission path) to all the switches (Switch 1 to Switch 5) on the set path (S330). The switch on the established path may modify its forwarding table to allow the packet to be delivered to the optimal path (S340).

FIG. 4 is a diagram illustrating a comparison between a handoff procedure and an existing handoff procedure according to an embodiment of the present invention. Referring to FIG.

FIG. 4 shows a conventional handoff scheme and a handoff scheme according to an embodiment of the present invention. According to the existing method, the data sent from the CN is transferred to the path of CN-> PS (several PS if it moves many times) -> NS -> MN.

However, according to an embodiment of the present invention, the data sent by the CN is transferred to the path of the CN-> crossing switch-> NS-> MN. Therefore, there is an advantage that data can be transmitted through an optimal path even after handoff. Therefore, in the conventional method, the data transmission path is CN-> Switch '> ①-> ②-> ③-> Switch1-> ③-> ④-> Switch2-> ④-> Switch3-> MN, The data transmission path according to an embodiment of the present invention becomes CN-> Switch '> ①-> ②-> ④-> Switch3-> MN. That is, according to an embodiment of the present invention, the SDN controller 110 sets CS and sets the optimum data transmission so that the CS is included in the data transmission path. If handoff occurs multiple times, PS is the most recent PS.

5 is a flow diagram illustrating a mobility management technique in accordance with an embodiment of the present invention. 5 is a flowchart illustrating a handoff process according to an embodiment of the present invention.

The MN generates a handover trigger signal immediately before leaving the PS, and the generated handover trigger signal is transmitted to the SDN controller through the PS (S1, S2). The handover trigger signal may include information on the NS. The SDN controller that received the handover trigger can determine the CS (S3). The SDN controller may request packet buffering to the CS (S4). In this case, the CS may respond through a confirmation request message (Buffering request Ack) (S5). Because the CS is usually not far from the MN's location, it can prevent packet loss and at the same time minimize packet delivery costs and delay jitter.

When the MN is moved to the NS (S6), the SDN controller can set an optimal path from CS to NS (S7). That is, the data transmission path (packet transmission path) may include a first transmission path from CN to CS and a second transmission path from CS to NS. The first transmission path may be the same as the first virtual path up to CN and PS used and the second virtual path overlapping CN to NS when the crossover switch is determined. And the second transmission path may be set in consideration of at least one of the number of hops and the traffic condition according to the policy of the SDN controller.

When the MN moves to the NS, the NS can perform the location registration process by transmitting the location registration message to the SDN controller. That is, when the MN transmits a location registration message to the SDN controller (S8), the SDN controller responds with a location acknowledgment (LACK) message (S9).

Then, the SDN controller updates the forwarding table of all switches located on the set optimal data transmission path (S10, S11). The data sent from the CN is transmitted to the CS and buffered. When the handoff is completed, the data is sent to the MN. Therefore, the CS packet can be transmitted to the new optimal path. The data sent by the CN after the handoff is forwarded to the path of CN-> cross-switch-> NS-> MN.

The mobility management technique according to an embodiment of the present invention may be applied to the location management server 120 connected to the SDN controller 110 and the SDN controller 110, Are distributedly distributed in accordance with the path calculation. In SDN, the controller manages the topology and traffic of the network in a centralized manner, thus providing a more optimal path. In particular, the existing distributed mobility management technique is disadvantageous in that it can not use an optimal path due to a forwarding function between neighboring switches when a handoff occurs. However, according to an embodiment of the present invention, It is advantageous to reduce the delay of the overall packet transmission.

The above-described mobility management technique may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable recording medium. At this time, the computer-readable recording medium may include program commands, data files, data structures, and the like, alone or in combination. On the other hand, the program instructions recorded on the recording medium may be those specially designed and configured for the present invention or may be available to those skilled in the art of computer software.

The computer-readable recording medium includes a magnetic recording medium such as a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical medium such as a CD-ROM and a DVD, a magnetic disk such as a floppy disk, A magneto-optical media, and a hardware device specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like.

The recording medium may be a transmission medium, such as a light or metal line, a wave guide, or the like, including a carrier wave for transmitting a signal designating a program command, a data structure, and the like.

The program instructions also include machine language code, such as those generated by the compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

The above-described mobility management technique and apparatus are not limited to the configuration and method of the above-described embodiments, but the embodiments may be modified such that all or some of the embodiments are selectively combined .

100: mobility management device
110: SDN controller
120: Location management server

Claims (10)

In a mobility management technique in a software defined networking environment,
Receiving a location registration message of a mobile node currently connected to the switch from the switch;
Maintaining a database storing identification information of the mobile node and location information of the mobile node mapped to the identification information;
Receiving a data transmission request from a transmitting node to the mobile node;
Determining a crossover switch, the crossover switch including a first virtual path from the transmitting node to a previous switch (PS, Previous Switch) and a second virtual path from the transmitting node to a next switch (NS, Next Switch) A switch located most distant from the transmitting node among the switches located in the path;
Setting a data transmission path from a switch to which the transmission node is connected to a switch to which the mobile node is currently connected, considering the at least one of the number of hops and the traffic situation so that the intersection switch is included; And
And transmitting the data transmission path to all switches located on the data transmission path. The method of claim 1, wherein the mobility management technique
And transmitting a data packet buffering command to the crossover switch. 3. The method of claim 2, wherein the first virtual path and the second virtual path
The number of hops, and the traffic situation. 3. The method of claim 2, wherein the mobility management technique
Further comprising the step of receiving a handover trigger signal including information of the next switch from the previous switch when a handoff occurs of the mobile node. 3. The method of claim 2,
Wherein the data transmission path includes a first transmission path to the transmission node and the crossover switch and a second transmission path to the crossover switch and the next switch,
Wherein the first transmission path is included in the first virtual path and the second virtual path, and the second transmission path is set in consideration of at least one of the number of hops and the traffic situation. A mobility management apparatus connected with a plurality of switches in a software defined networking environment,
Receiving a location registration message of a mobile node currently connected to the switch from the switch, receiving a data transmission request from the transmitting node to the mobile node, determining a crossover switch, including the crossover switch, An SDN controller for setting a data transmission path from a switch to which the transmission node is connected to a switch to which the mobile node is currently connected in consideration of at least one of the transmission nodes and the data transmission path to all switches located in the data transmission path, The crossover switch may be a switch located between a first virtual path to the transmitting node and a previous switch (PS, Previous Switch), and a switch located on a path where the second virtual path overlaps the transmitting node (NS, Next Switch) A switch located farthest from the node; And
And a location management server that maintains a database storing identification information of the mobile node and location information of the mobile node mapped to the identification information. 7. The apparatus of claim 6, wherein the SDN controller
And transmits a data packet buffering command to the crossover switch. 8. The method of claim 7, wherein the first virtual path and the second virtual path
The number of hops, and the traffic situation. 8. The apparatus of claim 7, wherein the SDN controller
Wherein the mobile node receives a handover trigger signal including information on the next switch from the previous switch when a handoff occurs in the mobile node. 8. The method of claim 7,
Wherein the data transmission path includes a first transmission path to the transmission node and the crossover switch and a second transmission path to the crossover switch and the next switch,
Wherein the first transmission path is included in the first virtual path and the second virtual path, and the second transmission path is set in consideration of at least one of the number of hops and the traffic situation.

Images