KR20130087918A - Method and system of distributed mobility control on network - Google Patents

Abstract

PURPOSE: A mobility supporting method having controlling functions distributed in a network and a system thereof are provided for network companies, which is providing IP mobility services to wireless mobile terminal subscribers, to avoid the concentration of control traffic and overhead to a particular device. CONSTITUTION: Multiple routers transmit packets from a transmission terminal to a reception terminal based on the identifying information of a mobile terminal. Multiple location management servers (LR 1-LR 7) are connected to a virtual network. The multiple location management servers transmits location binding information to a router corresponding to the reception terminal based on the identifying information of the mobile terminal received through the router. The location binding information includes the IP address of a packet reception terminal and the address of the router.

Description

METHOD AND SYSTEM OF DISTRIBUTED MOBILITY CONTROL ON NETWORK}

Embodiments of the present invention provide a network that distributes the location management and handover control of the terminal evenly over the network to solve the scalability problem of the IP mobility control system that may occur when there are a large number of mobile terminals on the network. The present invention relates to a mobility support method and a system in which control functions are distributed on an image.

Recently, with the advent of portable smart terminals such as smart phones and tablet PCs, the mobile internet traffic has surged, and mobile communication providers are making great efforts to cope with them. Moreover, as the demand for mobile Internet traffic is expected to increase due to the activation of portable smart terminal-based multimedia services, the interest in IP (Internet Protocol) mobility control technology for efficiently processing mobile traffic is expected to increase. .

The current Internet mobility control technology is characterized by a centralized method based on a hierarchical network structure, which cannot cope with the rapidly increasing demand for mobile Internet traffic.

Mobile IPv4 (RFC 3344), Mobile IPv6 (RFC 3775), Dual Stack-Mobile IPv6 (RFC 5555), Proxy Mobile IPv6 (RFC 5213), which have been standardized by the Internet Engineering Task Force (IETF) to date. Dual Stack-Proxy Mobile IPv6 (RFC 5844) is a centralized technology that handles location management and control of mobile terminals in a central server such as a home agent (HA) or a localized mobility agent (LMA). The disadvantages of such a centralized mobility control technology are summarized as follows.

(1) Deoptimization of Traffic Routing Paths

Although the Route Optimization function of the traffic delivery path is supported, basically all traffic is delivered through agents such as HA and LMA in the core network.

(2) low scalability

Since HA or LMA must manage location binding information and tunneling information of all terminals, it is difficult to embrace all the proliferating mobile terminals.

(3) Incompatibility with evolving mobile networks

Looking at the recent 4G LTE network structure, unlike the network structure used in previous 2G or 3G, the network structure is changing toward a flat architecture while maintaining a small number of managed nodes. The management method is not suitable for this structure.

(4) focus traffic on specific nodes

Since all traffic transmitted between an arbitrary terminal and a counterpart terminal in communication is transmitted through HA or LMA, a significant traffic load is placed on a specific node in the network.

(5) Single Point Of Failure (SPOF) Issues

If a specific node such as HA or LMA fails, the whole communication itself is disconnected.

Therefore, there is a need for a mobility support method capable of distributing control functions over a network due to such problems.

By solving the scalability problem of a system that provides IP mobility services of a large number of mobile terminals, network operators who provide IP mobility services to a large number of portable wireless terminal subscribers can help them avoid control traffic and overhead concentration on specific equipment. The present invention also provides a mobility support method and system in which control functions are distributed on a network capable of easily and efficiently expanding an IP mobility control system as the number of subscribers increases.

In a distributed mobility support network, a system for controlling IP (Internet Protocol) mobility is connected to a plurality of routers and virtual networks that transmit packets from a transmitting terminal to a receiving terminal based on identification information of the mobile terminal, and through the router. And a plurality of location management servers for transmitting location binding information including the IP address of the packet receiving terminal and the address of the router to a router corresponding to the receiving terminal, based on the received identification information of the mobile terminal, The location management server manages a key value assigned to itself and a key value assigned to the location management server that is inherited by the location management server that does not exist in the virtual network through a distributed hash table, and the own key value and the own value are inherited. IP that can calculate key value of location management server through Hash function By maintaining an address pool, the location binding information can be generated using the IP address pool.

By distributing mobility control functions such as location management server and IP address determination for mobile terminal, location query for packet transmission, etc. on network, network operators providing IP mobility service to many portable wireless terminal subscribers Can help to avoid control traffic and overhead concentration.

As the number of subscribers increases, the IP mobility control system can be expanded easily and efficiently, and the difficulty of managing terminal mobility due to the increase of mobile Internet traffic currently experienced by network operators can be solved.

1 is a diagram illustrating a distributed mobility support network structure according to an embodiment of the present invention.
2 is a diagram for describing packet transmission in a distributed mobility support network according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a Logical Overlay Network according to an embodiment of the present invention.
4 illustrates a virtual network and a distributed hash table according to an embodiment of the present invention.
5 is a diagram for describing a process of determining a home location registrar (HLR) and allocating an address according to an embodiment of the present invention.
6 is a diagram illustrating a location query and a packet forwarding process for a destination terminal according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a distributed mobility support network structure according to an embodiment of the present invention.

Referring to the drawings, in a distributed mobility support network, any mobile terminal may be connected to different access networks (ANs) such as WLAN, LTE, WiMax, etc. using one or more air interfaces.

When a mobile terminal is connected to an access network and connected to a mobility access gateway (MAG), which is a router managing the access network, signaling related to mobility is processed in the corresponding MAG. Then, the MAG forwards the packet arriving from the mobile terminal to the destination MAG through the Global Transit Network (GTN).

GTN is a network for general packet forwarding, and a Logical Overlay Network (LON) is a virtual network composed of location registrars (LRs) serving as location management servers of terminals and logical links therebetween.

The random LR (LR 1 ~ LR m) manages the location of the terminal assigned to them, and if necessary receives a request from the MAG informs the location of the specific terminal. Each LR constituting the LON may transmit a control message to each other through any routing method.

The first thing to be supported for the first terminal connected to the network is to determine a home LR (HLR) dedicated to location management of the terminal. That is, by assigning different HLRs for providing location management services to arbitrary terminals connected to the network, load equality effects on location management can be brought about.

When the terminal initially registers, the HLR receives a location registration message of the corresponding terminal, updates location management information that is managed by the HLR, and then sends a response message back to the corresponding terminal. Thereafter, even if the terminal moves to a new MAG, a location registration message for the corresponding terminal is sent to the HLR.

On the other hand, if the location registration to the HLR for any terminal is successfully made, the IP address for the corresponding terminal should be determined and assigned. The IP address assigned to any terminal is a fixed address that continuously supports mobility as long as the terminal exists in the network. That is, even if the UE connects to the new AN, the same IP address can be used so that the session maintained in the previous AN is maintained in the new AN.

2 is a diagram for explaining packet transmission in a distributed mobility support network.

As shown, when any terminal A (host A) in the distributed mobility support network starts to transmit packets to the terminal B (host B) connected to the MAG4 via MAG1, MAG1 receives the current location information for the terminal B. To find out, it sends a request message to the LON for the location information of the terminal B. At this time, the LR processing this request message becomes the HLR of the terminal B. The HLR sends a response message to the MAG1 in response to the request message, and MAG1 transmits packets to the location of the terminal obtained after receiving the response message (ie, MAG4).

FIG. 3 is a diagram illustrating a Logical Overlay Network according to an embodiment of the present invention. Hereinafter, a process of sending a location registration message by finding a HLR of a new terminal from a certain MAG to a LON will be described in more detail.

Any LRs can operate as DLR (Default LR) or HLR for any terminals. The DLR is determined by the MAG to which any UE is connected, and generally the LR closest to the MAG is selected. The HLR is an LR that manages location information on a corresponding UE. The MAG may finally query the HLR through the DLR when any terminal is initially connected or finds a destination of a packet to be transmitted to another terminal.

In the figure, for example, MAG1 queries LR5, which is an HLR connected to LON, via LR1, which is a DLR.

All the LRs constituting the LON can maintain a Distributed Hash Table (DHT). The location management servers LR 1 to LR 7 present in the LON are connected in a logical network structure in a ring form, and each location management server stores an arbitrary mobile terminal IP address and a MAG address where the terminal is currently located. Location Binding Information).

4 illustrates a virtual network and a distributed hash table according to an embodiment of the present invention.

As an example, assuming that the maximum number of LRs that can participate in the LON is R, this value may be arbitrarily determined by the network administrator, which may determine a range of hash function values to be described later.

Meanwhile, the following two hash functions may be used in the separation type mobility control method according to the present invention.

(1) H _ID : The terminal ID is input as an argument, and the LR key value from 0 to R-1 is calculated.

(2) H _ADDR : It takes LR IP address or terminal IP address as argument and calculates LR key value from 0 to R-1.

As shown in FIG. 4, a virtual network that can be composed of up to eight LRs (i.e., R = 8) and there are currently only four LRs (LR 0, LR 1, LR 3, LR 6) present in this network. In this case, each LR constitutes a logical network in the form of a ring including information of nodes that do not exist in the clockwise direction, and uses the key value calculated by inserting the H _ADDR hash function as the address of each LR as the ID of each LR.

On the other hand, any LR holds its key value in its distributed hash table and the key value of the LR that does not yet exist in the network. In the following, it is expressed that any LR is inherited having a key which is not its own. That is, LR 6 inherits not only its own key but also the keys of LR 4 and LR 5.

If any LR i inherits another LR j that does not exist in the network, the LR i may instead perform location management services that the non-existent LR j should be responsible for. Meanwhile, each LR knows information about its neighboring LRs connected in a ring form. Thus, to access another LR that is in the network (or does not exist), any LR searches along the ring-shaped network.

For example, in FIG. 4, LR 1 requests information from LR 3 located next to clockwise to access LR 5 which is not present in the network. LR 3 again requests information from LR 6, and since LR 6 inherits LR 5, which does not exist in the network, LR 6 eventually responds to LR 1's search request on behalf of LR 5.

As the number of LRs participating in the LON increases, the size of the distributed hash table increases and the search time to any LR increases. Chord (Ion Stoica, Robert Morris, David Karger, M. Frans Kaashoek, and Hari Balakrishnan, "chord: A Scalable Peer-to-Peer Lookup Service for Internet Applications", Proc. Of the 2001 Finger table configuration and routing method suggested by ACM SIGCOMM Conf., 2001) can also be used.

FIG. 5 is a diagram for describing a process of determining a home location registrar (HLR) and allocating an address according to an embodiment of the present invention. FIG. 6 is a diagram for a location of a destination terminal according to one embodiment of the present invention. A diagram illustrating a query and packet forwarding process.

First, a process of determining an HLR and assigning an address when a mobile terminal newly accesses a network will be described with reference to FIG. 5.

(1) Determination of Home LR for Location Registration of Any Host

When the terminal accesses the network, it informs the LR (ie, the DLR) located closest to the MAG to which the terminal is connected, and the DLR uses the hash function H _ID to identify the terminal's ID (terminal ID = mn1 @ in the drawing). etri.re.kr) to get LR key value. The DLR (LR 1) sends a location registration request to the LR inheriting the corresponding key. When a LR receives a location registration request message, it checks the key value stored in the message. If the value coincides with one of the key values of the LRs that are inherited, it becomes the HLR (LR 6) of the terminal that uses 'mn1@etri.re.kr' as its ID. When the MAG receives a response message for the location registration request message from the HLR, the HLR information about the terminal is stored in a cache, and the control message related to the terminal is directly transmitted to the HLR using the information stored in the cache. send.

(2) How to determine the HoA to assign to the host

Each LR can maintain a pool of IP addresses that can calculate each key value it inherits by the hash function H _ADDR . For example, in FIG. 5, LR 6 may maintain an IP address pool capable of calculating its key value and key values 4, 5, and 6 of its inherited LRs. IP1, IP2, IP3 and the like can be maintained as possible IPs. If the first LR receives a location registration request message by the terminal, if the key value in the message is found to be one of the keys of the LRs inherited from the terminal, the LR acts as an HLR for the terminal. Decide

Meanwhile, the HLR may select one of the addresses corresponding to the corresponding key from the pool of IP addresses managed by the HLR to maintain the terminal IP address and the current location information (MAG address) as location binding information. In FIG. 5, since IP1 is an address to be allocated to a new terminal, information <IP1, MAG # 1> may be maintained in the HLR as location binding information. In addition, when HLR forwards a response message for a location registration request received, the HLR forwards an address selected from an IP address pool, and the IP address is subsequently assigned to a terminal, so that the address used by the terminal at any location in the network is transmitted. do.

(3) Finding the location of the destination host of the packet for packet transmission

Hereinafter, a process in which a terminal having an ID of 'mn2@etri.re.kr' is delivered to a terminal having an ID of 'mn1@etri.re.kr' will be described with reference to FIG. 6.

In the present invention, an IP-based packet transmission method for transmitting IP address information in a packet can be used. In this case, DNS (Domain Name System) can be used to find the IP address of the destination host. When a terminal with an ID of 'mn2@etri.re.kr' transmits a destination IP address in a packet, the MAG (MAG # 2) managing the terminal transmitting the packet buffers the packet. The MAG sends a location query message including the IP address of the destination terminal to its DLR (LR 3). At this time, the DLR obtains a hash key value corresponding to the IP address of the destination terminal by using the H _ADDR hash function, and recognizes that the LR LR 6 corresponding to the key value is the HLR of the destination terminal. Thereafter, the DLR LR 3 of the packet transmitting terminal sends a location query message to the HLR LR 6 of the packet receiving terminal, which may include an IP address and a hash key value of the destination terminal.

The HLR (LR 6) of the packet receiving terminal receiving the location query message retrieves the IP address of the destination terminal from the location binding information managed by the packet receiving terminal and obtains the location of the corresponding terminal, that is, the MAG address information. Thereafter, the HLR LR 6 of the packet receiving terminal transmits a location query response message to the DLR LR 3 of the packet transmitting terminal to inform the location of the packet receiving terminal (ie, the receiving side MAG address). Receiving side MAG address information, the transmitting side MAG (MAG # 2) delivers the buffer that it has buffered to the receiving side MAG (MAG # 1), and the MAG (MAG # 1) delivers the packet to the destination terminal. Can be.

Accordingly, the distributed mobility control method and system on the network according to the present invention distributes mobility control functions such as location management server and IP address determination for mobile terminals and location query for packet transmission on the network, thereby providing a large number of portable wireless terminal subscribers. Network operators that provide IP mobility services to target networks can avoid control traffic and overhead concentration on specific equipment, and can easily and efficiently expand IP mobility control systems as the number of subscribers increases. The difficulty of terminal mobility management due to the increase of mobile internet traffic that operators are experiencing can be solved.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Claims (1)

In a system for controlling IP (Internet Protocol) mobility in a distributed mobility support network,
A plurality of routers for transmitting packets from the transmitting terminal to the receiving terminal based on the identification information of the mobile terminal; And
Connected to a virtual network and transmitting location binding information including an IP address of the packet receiving terminal and an address of the router to the router corresponding to the receiving terminal based on the identification information of the mobile terminal received through the router. Multiple location management servers
Lt; / RTI &gt;
The location management server,
A key value assigned to itself and a key value assigned to a location management server inherited by the location management server that does not exist in the virtual network are managed through a distributed hash table, and the own key value and the location management server inherited by the user And generating the location binding information by using the IP address pool by maintaining an IP address pool that can calculate a key value of a Hash function.

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