KR101556031B1 - Method and system of distributed mobility control on network - Google Patents

Abstract

Disclosed is a distributed mobility control method and system on a network. A system for controlling IP (Internet Protocol) mobility in a distributed mobility supporting network is connected to a plurality of routers and virtual networks for transmitting packets from a transmitting terminal to a receiving terminal based on identification information of the mobile terminal, And a plurality of location management servers for transmitting location binding information including an IP address of the packet receiving terminal and an 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 a location management server to which the location management server does not exist in the virtual network through a distributed hash table, Which can calculate the key value of the location management server through the hash function By maintaining an address pool, the location binding information can be generated using the IP address pool.

Description

[0001] METHOD AND SYSTEM FOR DISTRIBUTED MOBILITY CONTROL ON NETWORK [0002]

Embodiments of the present invention provide a method and apparatus for distributing a location management and a handover control function of a terminal evenly over a network in order to solve the scalability problem of an IP mobility control system that may occur when a large number of mobile terminals exist on a network. And more particularly, to a mobility support method and system in which control functions are distributed on a mobile station.

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

The current Internet mobility control technology is characterized by a centralized method based on a hierarchical network structure, which makes it difficult to meet 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), and Internet Protocol (IP) based mobility protocols that have been standardized by the Internet Engineering Task Force Dual Stack-Proxy Mobile IPv6 (RFC 5844) is a centralized technology that handles the location management and control of mobile terminals in central servers such as HA (Home Agent) and LMA (Localized Mobility Agent). The drawbacks of this centralized mobility control technology are summarized as follows.

(1) non-optimization of the traffic routing path

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

(2) Low scalability

It is difficult to accommodate all of the rapidly increasing mobile terminals since HA and LMA need to manage location binding information and tunneling information of all terminals.

(3) Incompatibility with evolving mobile communication networks

In recent 4G LTE network structure, unlike the previous 2G or 3G network structure, the network structure is changing toward a flat architecture while maintaining a small number of management nodes, and centralized mobility The management method is not suitable for such a structure.

(4) Concentration of traffic to a specific node

All traffic transmitted between an arbitrary terminal and a counterpart terminal in communication is transmitted through an HA or an LMA, so that a considerable traffic load is applied to a specific node in the network.

(5) Single point of failure (SPOF) problem

If a failure occurs in a specific node such as HA or LMA, the entire communication itself is disconnected.

Accordingly, there is a demand for a mobility support method that can distribute control functions over a network due to such problems.

By solving the scalability problem of a system providing IP mobility service of many mobile terminals, it is possible to support network carriers providing IP mobility service to many portable wireless terminal subscribers to avoid concentration of control traffic and overhead for specific equipment And a mobility support method and system in which control functions are distributed on a network capable of easily and efficiently expanding the IP mobility control system as the number of subscribers increases.

A system for controlling IP (Internet Protocol) mobility in a distributed mobility supporting network is connected to a plurality of routers and virtual networks for transmitting packets from a transmitting terminal to a receiving terminal based on identification information of the mobile terminal, And a plurality of location management servers for transmitting location binding information including an IP address of the packet receiving terminal and an 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 a location management server to which the location management server does not exist in the virtual network through a distributed hash table, Which can calculate the key value of the location management server through the hash function By maintaining an address pool, the location binding information can be generated using the IP address pool.

By distributing the mobility control functions such as the location management server and the IP address determination for the mobile terminal and the location query for the packet transmission on the network, network operators providing IP mobility services to many mobile wireless terminal subscribers can search for specific equipment Control traffic and overhead convergence.

As the number of subscribers increases, IP mobility control system can be easily and efficiently extended, and it is possible to solve the difficulty of terminal mobility management due to the increase of mobile Internet traffic currently suffered by network operators.

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

Referring to the drawings, a mobile terminal in a distributed mobility support network can be connected to a different access network (AN) such as WLAN, LTE, WiMax, etc. using one or more wireless interfaces.

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

GTN is a network for general packet forwarding, LON (Logical Overlay Network) is a virtual network composed of LR (Location Registrars) serving as location management servers of terminals and logical links between them.

An arbitrary LR (LR 1 to LR m) manages the location of the terminals allocated to the terminal, and when required, receives a request from the MAG and informs the location of the terminal. Each LR constituting the LON can transmit control messages to each other through an arbitrary routing method.

The first priority for the terminal connected to the network is to determine the HLR (Home LR) dedicated to the location management of the terminal. That is, the HLRs to be provided with the location management service can be assigned differently to any terminal connected to the network, so that the load balancing effect on the location management can be obtained.

When the terminal performs initial registration, the HLR receives the location registration message of the corresponding terminal, updates the location management information managed by the terminal, and transmits the response message to the terminal again. Even if the terminal moves to the new MAG, the location registration message for the terminal is sent to the HLR.

On the other hand, if location registration to an HLR for an arbitrary terminal is successfully performed, an IP address for the terminal should be determined and assigned. The IP address assigned to an arbitrary terminal is a fixed address for which mobility is continuously supported as long as the terminal exists in the network. That is, even if the terminal 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 a certain terminal A starts transmitting packets to a terminal B (host B) connected to the MAG 4 via the MAG 1 in the distributed mobility support network, the MAG 1 transmits current location information about the terminal B And transmits a request message inquiring the location information of the terminal B to the LON in order to find out. At this time, the LR processing the request message becomes the HLR of the terminal B. The HLR transmits a response message to the MAG1 in response to the request message, and the MAG1 transmits the packets to the location of the terminal (i.e., MAG4) obtained after receiving the response message.

3 is a diagram illustrating a virtual network (Logical Overlay Network) according to an embodiment of the present invention. Hereinafter, a process of searching for a new terminal's HLR from a certain MAG to LON and sending a location registration message will be described in detail with reference to the drawings.

Any LRs may operate as a DLR (Default LR) or HLR for any of the terminals. The DLR is determined by the MAG to which an arbitrary terminal is connected. In general, the LR closest to the MAG is selected. The HLR is an LR that manages location information for the terminal. The MAG can query the HLR eventually through the DLR when an arbitrary terminal finds the destination of a packet that it is initially connected to or that it wants to transmit to another terminal.

In the drawing, for example, MAG1 refers to LR5, which is the HLR connected to LON through LR1, which is DLR.

All LRs constituting the LON can maintain a distributed hash table (DHT). The location management servers LR 1 to LR 7 in the LON are connected in a ring logical network structure. Each location management server transmits an arbitrary mobile terminal IP address and a MAG address in which the terminal is currently located to location binding information Location Binding Information).

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

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

Meanwhile, the following two hash functions can be used in the granularity mobility control method according to the present invention.

(1) H _ID : Input terminal ID as an argument, and calculate LR key value from 0 to R-1.

(2) H _ADDR : Input the LR IP address or terminal IP address as an argument and calculate the LR key value from 0 to R-1.

(LR 0, LR 1, LR 3, LR 6) are actually present in the network, and a virtual network which can be composed of a maximum of eight LRs as shown in FIG. 4 , Each LR constructs a logical network in the form of a ring including the information of nodes that do not exist in the clockwise direction and uses the key value calculated by putting into the _HADDR hash function as the address of each LR as the ID of each LR.

On the other hand, an arbitrary LR holds its own key value in its distributed hash table and the LR key value which does not yet exist in the network. Hereinafter, it is expressed that any LR succeeds having a key other than itself. That is, LR 6 inherits the keys of LR 4 and LR 5 as well as its own key.

If any LR i inherits another LR j that does not exist in the network, then LR i can perform the location management service that LR j that it does not have to take charge of. On the other hand, each LR knows information about its neighbor LRs connected in a ring form. Thus, in order for an arbitrary LR to access another LR that exists (or does not exist) in the network, the search is performed along a ring-shaped network.

For example, in FIG. 4, LR 1 requests information from LR 3 located in the clockwise direction to access LR 5 not present in the network. LR 3 again requests information from LR 6, and LR 6 inherits LR 5, which does not exist in the network, so LR 6 replaces LR 5 in response to LR 1's search request.

The larger the number of LRs participating in the LON, the larger the size of the distributed hash table and the longer the search time to an arbitrary LR. In order to increase the efficiency of search, 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 ACM SIGCOMM Conf., 2001) can be used.

FIG. 5 is a diagram illustrating a process of determining an HLR (Home Location Registrar) and assigning an address according to an exemplary embodiment of the present invention. FIG. Query and packet delivery process.

First, referring to FIG. 5, a process of determining an HLR when an arbitrary mobile terminal is newly connected to a network and allocating an address will be described.

(1) Home LR determination method for location registration of arbitrary host

When the terminal accesses the network, the terminal informs the LR (i.e., DLR) located nearest to the MAG to which the terminal is connected, and DLR notifies the _ID of the corresponding terminal (terminal ID = mn1 @ etri.re.kr) corresponding to the LR key. DLR (LR 1) sends a location registration request to the LR inheriting the key. When an arbitrary LR receives a location registration request message, it checks the key value stored in the message. If the value matches one of the key values of the LRs inherited, it becomes the HLR (LR 6) of the terminal using 'mn1@etri.re.kr' as ID. When the MAG receives a response message for the location registration request message from the HLR, the MAG stores the HLR information for the corresponding terminal in a cache, and then the control message related to the terminal is directly transmitted to the HLR send.

(2) How to determine HoA to assign to host

Each LR can maintain an IP address pool that can calculate each key value inherited by the hash function H _ADDR . For example, in FIG. 5, LR 6 can maintain an IP address pool that can calculate its key value and the key values 4, 5, and 6 of LRs inherited by the LR 6. IP1, IP2, IP3 and so on can be maintained. If an arbitrary LR receives a location registration request message from the terminal for the first time, if it is confirmed that the key value in the message is one of the keys of the LRs inherited by the terminal, the terminal performs its role as the HLR for the terminal .

Meanwhile, the HLR can select one of the addresses corresponding to the corresponding key in the IP address pool managed by the HLR and 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 such as < IP1, MAG # 1 > may be maintained as location binding information in the HLR. When the HLR transmits a response message to the location registration request received from the HLR, the HLR transmits an address selected from the IP address pool, and the IP address is allocated to the terminal after that, do.

(3) How to locate the destination host of the packet for packet transmission

Hereinafter, with reference to FIG. 6, a process of transmitting a packet to a terminal having an ID 'mn1@etri.re.kr' as 'mn2@etri.re.kr' will be described as an example.

In the present invention, an IP-based packet transmission method in which IP address information is transmitted when a packet is transmitted can be used. In this case, DNS (Domain Name System) can be used to find the IP address of the destination host. When the terminal having the ID 'mn2@etri.re.kr' inserts the destination IP address into the 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 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. Then, the DLR (LR 3) of the packet transmitting terminal sends a location inquiry message to the HLR (LR 6) of the packet receiving terminal, which may include the IP address of the destination terminal and the hash key value.

The HLR (LR 6) of the packet receiving terminal receiving the location inquiry message searches the IP address of the destination terminal from the location binding information managed by the HLR (LR 6) and obtains the location of the corresponding terminal, that is, the MAG address information. The HLR (LR 6) of the packet receiving terminal then 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 (that is, the receiving MAG address). The transmitting MAG (MAG # 2) receiving the receiving-side MAG address information transfers the buffered packet to the receiving-side MAG (MAG # 1), and the MAG (MAG # 1) transfers the packet to the destination terminal .

Therefore, the distributed mobility control method and system on the network according to the present invention distributes mobility control functions such as the location management server for the mobile terminal, the IP address determination, and the location query for packet transmission on the network, The IP mobility control system can be easily and efficiently extended according to the increase in the number of subscribers, and the network mobility control system can be easily and efficiently extended to the current network It is possible to solve the difficulty of terminal mobility management due to an increase in mobile Internet traffic experienced by operators.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill 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. 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 (10)

A distributed mobility support method for a distributed mobility support network,
Wherein the distributed mobility support network comprises:
A Global Transit Network comprising a plurality of routers for packet transmission and reception; And
A logical overlay network (LLR) composed of logical links of a plurality of location registers (LRs) for managing the location information for transmitting and receiving the packets by the plurality of routers,
Wherein the distributed mobility support method comprises:
Assigning a key value generated through a first hash function to a location management server of one of the plurality of location management servers;
Storing a plurality of Internet Protocol (IP) addresses capable of calculating the key value through the first hash function in a location management server allocated with the key value;
Determining a home location server (HLR) that controls the mobility of the mobile terminal, the location management server having the same key value as the key value generated through the second hash function; And
Selecting one of the plurality of IP addresses stored in the home location management server and assigning the selected IP address to the IP address of the mobile terminal
/ RTI &gt;
How to support distributed mobility.
The method according to claim 1,
Storing location binding information including an address of a router connected to the mobile terminal and an IP address of the mobile terminal in the home location management server
&Lt; / RTI &gt;
How to support distributed mobility.
The method according to claim 1,
The identification information of the mobile terminal is inputted by a default location register (DLR) located nearest to the router connected to the mobile terminal among the plurality of location management servers, and the identification information of the mobile terminal is inputted through the second hash function The key value is generated,
How to support distributed mobility.
The method of claim 3,
The default location management server transmits a location registration message including the key value generated through the second hash function, the location of the router connected to the mobile terminal, and the identification information of the mobile terminal to the home location management server For example,
Wherein the home location management server transmits a response message including the IP address assigned to the mobile terminal to the default location management server,
How to support distributed mobility.
The method according to claim 1,
The key value generated through the first hash function is generated by inputting the IP address of the location management server,
Wherein the key value generated through the second hash function is generated by inputting identification information of the mobile terminal,
How to support distributed mobility.
The method according to claim 1,
Wherein the plurality of location management servers include a plurality of virtual location management servers and a plurality of actual location management servers,
The key values assigned to the actual location management server are stored in the actual location management server and the key values assigned to the plurality of virtual location management servers are stored in the actual location management server by a predetermined method ,
How to support distributed mobility.
The method according to claim 6,
Wherein a plurality of IP addresses corresponding to key values stored in the actual location management server are stored in the actual location management server,
How to support distributed mobility.
The method according to claim 1,
Wherein the number of key values generated by the first hash function and the number of key values generated by the second hash function are equal to the number of the plurality of location management servers,
How to support distributed mobility.
A distributed mobility support method for a distributed mobility support network,
Wherein the distributed mobility support network comprises:
A Global Transit Network comprising a plurality of routers for packet transmission and reception; And
A logical overlay network (LLR) composed of logical links of a plurality of location registers (LRs) for managing the location information for transmitting and receiving the packets by the plurality of routers,
Wherein the distributed mobility support method comprises:
Generating a key value by inputting the IP address of the receiving terminal received from the first router connected to the transmitting terminal to the hash function;
Retrieving location information of the receiving terminal stored in a home location management server that is assigned the key value by the hash function among the plurality of location management servers and controls mobility of the receiving terminal; And
Transmitting a packet from the transmitting terminal to the receiving terminal based on the searched location information of the receiving terminal
/ RTI &gt;
How to support distributed mobility.
10. The method of claim 9,
Wherein the IP address is received by a default location management server located closest to the first router among the plurality of location management servers,
The default location management server transmits a location inquiry message including the IP address and the key value to the home location management server,
The home location management server transmits the location information including the address of the second router connected to the receiving terminal to the default location management server,
The first router receiving the address of the second router from the default location management server transmits the packet to the second router using the address of the second router,
How to support distributed mobility.

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