Abstract:
Provided is a method of providing an Internet Protocol (IP)-based mobility service, particularly, a method of providing seamless quality of service (QoS) guarantees when an IP-based mobile service is provided. The seamless QoS management method includes: a method of providing seamless QoS guarantees when an Internet Protocol (IP)-based mobility service is provided, including: determining whether a terminal is newly registered in a network connecting unit; and providing QoS information of the newly registered terminal to the network connecting unit. Therefore, a user can successively receive a Service Level Agreement (SLA)-based service for which he or she subscribes, while moving to other places.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from Korean Patent Application No. 10-2007-0133346, filed on Dec. 18, 2007, the disclosure of which is incorporated herein in its entirety by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a method of providing an IP-based mobility service, and more particularly, to a method of providing seamless QoS guarantees when an Internet Protocol (IP)-based mobile service is provided. 
         [0004]    This work was supported by the IT R&amp;D program of Ministry of Information and Communication (MIC)/Institute for Information Technology Advancement (IITA) [2007-S-013-01, R&amp;D on all IPv6 based Fixed-Mobile convergence networking technology]. 
         [0005]    2. Description of the Related Art 
         [0006]    Recently, many users are using a network service such as the Internet while they are moving as well as when they stay in a predetermined region. Accordingly, in a next-generation network (NGN), a service of proving IP mobility is important. Accordingly, development of various techniques for providing IP mobility is needed. 
         [0007]    Conventionally, a method of providing IP mobility based on a mobile IP (MIP) of Internet Engineering Task Force (IETF) has been mainly used, however, the method could not be applied practically due to a limitation in the MIP. 
         [0008]    Also, no method for providing seamlessly QoS guarantees of a service which is presently used when a user and a terminal are moving has been developed. 
         [0009]    A terminal has a permanent IP address (based on IPv6) not participating in data transmission, and a transport IP address (based on IPv4 or IPv6) participating in actual data transmission. The permanent IP address is used as an identifier (ID) through which the location of the terminal is registered and the terminal is authenticated. Actual data transmission is performed using the transport IP address. If a network connecting apparatus is changed when the terminal is moved, a network transmission apparatus assigns a new transport IP address to the terminal. An IP mobility control apparatus binds and stores the permanent IP address and transport IP address of the terminal, obtains location information of the terminal using the stored information, and performs mobile control for seamlessly proving a service based on the location information. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a method for providing seamless QoS guarantees for a service which is currently provided, even if a network connecting apparatus is changed when a subscriber or a terminal which is using the service is moving. 
         [0011]    According to an aspect of the present invention, there is provided a method of providing seamless quality of service (QoS) guarantees, which is performed by a network control unit to control a network connecting unit for connecting a terminal to a service network, when an Internet Protocol (IP)-based mobility service is provided, the method including: when a terminal performs handover, recognizing that a network connecting unit in which the terminal has been registered is changed to a different network connecting unit; and providing QoS information of the terminal to the different network connecting unit. 
         [0012]    The recognizing includes recognizing that the network connecting unit in which the terminal has been registered is changed to the different network connecting unit, by acquiring a transport IP address of the terminal and the QoS information of the terminal, which is transmitted from a network control unit. The providing of the QoS information includes transmitting the QoS information of the terminal to the different network connecting unit using the transport IP address of the terminal. 
         [0013]    The method of providing seamless quality of service (QoS) guarantees includes: acquiring a permanent IP address of the terminal and the transport IP address of the terminal and requesting the QoS information of the terminal using the permanent IP address of the terminal; acquiring the QoS information of the terminal in response to the request; and transmitting the QoS information of the terminal to the different network connecting unit using the transport IP address of the terminal. 
         [0014]    Therefore, a user can successively receive a Service Level Agreement (SLA)-based service for which he or she subscribes, while moving to other places. 
         [0015]    Additional aspects of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. 
         [0016]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention, and together with the description serve to explain the aspects of the invention. 
           [0018]      FIG. 1  is a block diagram of a system for providing seamless quality of service (QoS) guarantees, according to an embodiment of the present invention; 
           [0019]      FIG. 2  is a flowchart of a method of providing seamless QoS guarantees, according to an embodiment of the present invention; and 
           [0020]      FIG. 3  shows data flow of a method of providing seamless QoS guarantees according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0021]    The invention is described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like elements. 
         [0022]      FIG. 1  is a block diagram of a system for providing seamless quality of service (QoS) guarantees, according to an embodiment of the present invention. 
         [0023]    As illustrated in  FIG. 1 , the seamless QoS guarantee system includes a plurality of subsets including a plurality of terminals  10   a,    10   b,  . . . ,  10   n  and a plurality of wireless connection units  20   a,    20   b,  . . . ,  20   n;  a plurality of network connecting units  30   a,    30   b,  . . . ,  30   n  for connecting the respective subnets to a service network; a network control unit  50  for controlling the service network; an IP mobility control unit  40  for controlling IP mobility of the terminals  10   a,    10   b,  . . . ,  10   n;  and a policy server  60  including a user database (DB)  65  for storing policy information of the terminals  10   a,    10   b,  . . . ,  10   n  and user QoS information. 
         [0024]    The terminals  10   a,    10   b,  . . . ,  10   n  may be communication terminals, such as Personal Digital Assistants (PDAs), and notebooks, which use IP addresses as a Identifier. The wireless connection units  20   a,    20   b,  and  20   n  may be access points for controlling an access network. The terminals  10   a,    10   b,  . . . ,  10   n  can be connected to the network connecting units  30   a,    30   b,  . . . ,  30   n  through the wireless connection units  20   a,    20   b,  . . . ,  20   n.    
         [0025]    The network connecting units  30   a,    30   b,  . . . ,  30   n  are used to connect the terminals  10   a,    10   b,  . . . ,  10   n  to a service server, and may be routers. The terminals  10   a,    10   b,  . . . ,  10   n  are connected to a service network through the wireless connection units  20   a,    20   b,  . . . ,  20   n  and the network connecting units  30   a,    30   b,  . . . ,  30   n,  to thus receive a service. Here, various services can be provided to the terminals  10   a,    10   b,  . . . ,  10   n,  depending on functions of an application server  70  connected to the service network. Particularly, the service provided through the service network may be a client/server type service which is provided between the terminals  10   a,    10   b,  . . . ,  10   n  and the application server  70 , or a point-to-point type service which is provided between different terminals  10   a,    10   b,  . . . ,  10   n.    
         [0026]    The IP mobility control unit  40  performs control related to IP mobility of the terminals  10   a,    10   b,  . . . ,  10   n  which are connected to the service network through the network connecting units  30   a,    30   b,  . . . ,  30   n.    
         [0027]    Then, the network control unit  50  controls the network connecting units  30   a,    30   b,  . . . ,  30   n  based on mobility policy information of terminals which is acquired from the policy server  60 . 
         [0028]    Here, the network control unit  50  acquires service subscriber information, service QoS information, etc., from the policy server  60 , and allows the network connecting units  30   a,    30   b,  . . . ,  30   n  to control transmission of packet data according to Service Level Agreement (SLA) of the corresponding service subscriber. 
         [0029]    If the terminals  10   a,    10   b,  . . . ,  10   n,  which are using the service, for example, are moving between the subnets, the network control unit  50  provides context information about the corresponding service of the terminals  10   a,    10   b,  . . . ,  10   n,  to the network connecting units  30   a,    30   b,  . . . ,  30   n  to which the terminals  10   a,    10   b,  . . . ,  10   n  are newly connected, when the terminals  10   a,    10   b,  . . . ,  10   n  perform handover. For example, the terminal  10   a,  which is using the service through the network connecting unit  30   a,  performs handover to move the location of the terminal  10   b.  In this case, the network control unit  50  provides context information about the corresponding service of the terminal  10   a  to the network connecting unit  30   b  to which the terminal  10   a  is newly connected 
         [0030]    Hereinafter, a method for providing seamless QoS guarantees will be described with reference to  FIGS. 2 and 3 . 
         [0031]      FIG. 2  is a flowchart of a method for providing seamless QoS guarantees, according to an embodiment of the present invention. 
         [0032]    Referring to  FIGS. 1 and 2 , when the terminal  10  performs handover, the terminal  10  transmits to the IP mobility control unit  40  a handover notification for notifying that handover is performed (operation S 200 ). Here, the term “handover” means newly registering the terminal  10  in a network connecting unit  30  of a different subnet when the terminal  10  is moved to the different subnet. 
         [0033]    Here, the terminal  10  transfers a permanent IP address and a transport IP address of the terminal  10  to the IP mobility control unit  40  when the terminal  10  performs handover. The IP mobility control unit  40  determines whether a service is allowed to the terminal  10  on the basis of the permanent IP address and transport IP address of the terminal  10  (operation S 210 ). If the service is not allowed to the terminal  10  or to a user of the terminal, the service is blocked (operation s 215 ). If the service is allowed to the terminal  10 , the IP mobility control unit  40  transfers mobility information including the permanent IP address, previous transport IP address, and newly received transport IP address of the terminal  10  to the network control unit  50  (operation S 220 ). The network control unit  50  requests user QoS information to a policy server  60  on the basis of the mobility information of the terminal  10 . Then, the network control unit  50  acquires the user QoS information from the policy server  60  (operation S 230 ), and transfers the user QoS information to the network connecting unit  30  (operation S 240 ). Then, the network connecting unit  30  stores the user QoS information, processes traffic data according to the QoS information, and provides the result of the processing to the terminal  10 . 
         [0034]      FIG. 3  shows data flow of a method for providing seamless QoS guarantees, according to an embodiment of the present invention. 
         [0035]    A terminal  10  which is connected to a different network connecting unit  30  by handover transmits to an IP mobility control unit  40  a handover notification for notifying that handover is performed (operation S 300 ). Here, the handover notification includes a permanent IP address of the terminal  10 , and a transport IP address of the terminal  10  changed by the handover. 
         [0036]    Here, the IP mobility control unit  40  stores the permanent IP address of the terminal  10 , and a transport IP address which has been assigned by a home network and has been used by the terminal  10  before the handover is performed. If the handover notification is received from the terminal  10 , the mobility control unit  40  updates the transport IP address of the terminal  10  to a newly changed transport IP address on the basis of the permanent IP address of the terminal  10 . 
         [0037]    Thereafter, the IP mobility control unit  40  determines whether a service subscriber and the terminal  10  has been moved, and notifies the network control unit  50  of the movement of the terminal  10  (operation S 310 ). That is, the IP mobility control unit  40  transmits the permanent IP address of the terminal  10 , the previous transport IP address of the terminal  10 , and the newly changed transport IP address to the network control unit  50 , thereby notifying the network control unit  50  of the movement of the terminal  10 . At this time, the user QoS information can also be transmitted to the network control unit  50 . That is, if the network control unit  50  receives both address information of the terminal  10  and user QoS information from the IP mobility control unit  40 , the network control unit  50  can perform network resource control on the basis of the address information and QoS information. 
         [0038]    Meanwhile, if the network control unit  50  receives only address information of the terminal  10  from the IP mobility control unit  40 , the network control unit  50  requests QoS information of the terminal  10  to the policy server  60  (operation S 320 ). The request of the QoS information may include the permanent IP address of the terminal  10 . The policy server  60  can obtain user QoS information of the terminal  10  with reference to user DB. The user QoS information and the permanent IP address of the terminal  10  are bound and stored in the user DB. The policy server  60  extracts the user QoS information from the user DB on the basis of the permanent IP address of the terminal  10  (operation S 325 ), and transfers the user QoS information to the network control unit  50  (operation S 330 ). 
         [0039]    The network control unit  50  controls network resources using the user QoS information received from the policy server  60 . The network control unit  50  transfers the user QoS information to a network connecting unit  30  (operation S 340 ). The network connecting unit  30  stores the user QoS information, and processes traffic transmitted to the terminal  10  on the basis of the user QoS information (operation S 345 ). 
         [0040]    Meanwhile, the method of providing seamless QoS guarantees may be written as a computer program. Also, the program may be stored in computer readable media, and read and executed by a computer. The computer readable media may be a magnetic recording medium, an optical recording medium, etc. 
         [0041]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.