Abstract:
A resource allocation device includes a database of user and service information, a resource allocation management unit for determining whether a service request agrees with a service level agreement and whether it accepts a resource allocation request, a service level agreement unit for negotiating the service level agreement with the user, sending the received service request to the resource allocation management unit, acquiring the result of the resource allocation request, and transmitting the result of the resource allocation request to the user, a routing information management unit for obtaining a network configuring information, storing the network configuring information in the database, discovering the path to provide the service and storing the discovered path in the database to be reused and a policy control management unit for deciding a policy according to whether the service request and the resource allocation request are accepted.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to and the benefit of Korean Patent Application 10-2004-0096375 filed in the Korean Intellectual Property Office on Nov. 23, 2004, the entire content of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     (a) Field of the Invention  
         [0003]     The present invention relates generally to a resource allocation device for providing a differentiated service and a method thereof. More particularly, the present invention relates to a resource allocation device and a method thereof using a path storage device wherein the path connects a border router of a domain including a source with a border router of a domain including a destination.  
         [0004]     (b) Description of the Related Art  
         [0005]     Recently, in Internet services, expectations about Quality of Service (QoS), such as large bandwidth and low delay, have become higher than ever. Particularly, since Internet services are based on the Internet Protocol (IP), more reliable, guaranteed QoS than that of the Internet should be supported. However, there is no way to guarantee that packets will be reliably delivered to the destination in the current Internet system. Therefore, various solutions have been provided to guarantee a high quality of service.  
         [0006]     Particularly, an Integrated Service (Intserv) using a Resource Reservation Protocol (RSVP) has been provided. The Intserv has problems in several aspects. In detail, reserving resources per-flow introduces severe scalability and information maintenance problems, and supporting RSVP protocol in the current application programs introduces severe scalability and compatibility problems. More recently, a Differentiated Service (DiffServ) has been developed to provide differentiated services instead of a Simple Best Effort Service, and simultaneously to solve the scalability and compatibility problems.  
         [0007]     The DiffServ is designed to improve an IPv4 priority marking service defined by RFC 791 and to provide various services on the Internet. The DiffServ is implemented by means of predefining a service aggregation having an end to end priority, defined as Per-Hop Behavior (PHB). Thus, it is unnecessary to maintain an information regarding service. Also, it can be realized with only a small amendment of the current network.  
         [0008]     Korean Application No. 1999-55830, filed on Dec. 8, 1999, entitled “connection admission control method and apparatus using status of routers in differentiated service network” is incorporated herein by reference.  
         [0009]     This prior art discloses a connection admission control device and method using status of routers in a differentiated service IP network so as to provide a reliable, QoS guaranteed service to a user. This device and method uses status of a core router, which is installed in the path through which the user data is really passing, as well as status of an edge router and a service level agreement (SLA) to implement a connection admission control processing. Therefore, the connection admission control processing may be performed reliably so as to provide a QoS guaranteed service.  
         [0010]     Also, Korean Application No. 2003-13509, filed on Mar. 4, 2003, entitled “Apparatus for allocation resources based on path color for providing differentiated service and method thereof” is incorporated herein by reference. In detail, this device and method uses a resource allocation device and method based on a path color to provide a differentiated service. Therefore, the user can be provided with a priority service according to a request and the current standard differentiated service can be commercialized.  
         [0011]     Meanwhile, in order to guarantee QoS of the differentiated service model, it is necessary to provide a device for managing/monitoring network resources, catching the specified resource corresponding to the user request, and deciding accept/reject. Such a device is called a Bandwidth Broker.  
         [0012]     Logically, it appeared that only one bandwidth broker exists in one domain. But, physically, one bandwidth broker may include various secondary devices.  
         [0013]     For example, when the user requests a bandwidth broker to use a resource, the bandwidth broker decides to accept/reject a request, considering general flow information. When the request is accepted, the border router marks a Differentiated Service Code Point (DSCP) matching with the PHB on a packet of the user.  
         [0014]     At this time, a Resource Allocation Request (RAR) indicates a desired amount of resource and an available reservation period. To handle these requests of the user, the bandwidth broker stores various Service Level Agreements (SLA) and the bandwidths allocated per SLA, in a database as the basic information for later deciding an allocation amount. The bandwidth broker allocates the priority service based on the basic information to the user in response to the request, and functions to configure a communication network router such that the predefined service is correctly delivered. Also, the bandwidth broker communication is classified into two types, a domain to domain communication and a communication in domain. The communication in domain may be desired to be standardized, since the domain can use different installations and mechanisms. The communication in domain may be desired to decide whether RAR is accepted, especially on using an external policy server. However, the bandwidth broker communication has been concentrated on the PHB setting, since the communication in domain is not standardized and also most of the router manufacturers have been using respective methods to set the router.  
         [0015]     For example, a Simple Network management Protocol (SNMP), a Management Information Base (MIB), a Common Open Policy Service (COPS), and a Policy Information Base (PIB) are disclosed by a differentiated service working group of an Internet Engineering Task Force (IETF). The MIB and PIB have both been standardized in the form of an Internet draft (Draft).  
         [0016]     However, because these bandwidth broker software should manage a network irregardless of the type of routers, they can be installed in different type of routers, as well as MIB or PIB, to support a differentiated service.  
         [0017]     Also, because the bandwidth broker can control only resources in domain, it has a drawback that it cannot set routers of other domains. Therefore, pre-negotiated SLA are demanded between the adjacent domains For example, with the pre-negotiated SLA, the bandwidth broker accepts a bandwidth allocation request for the adjacent domains, and appoints a specified class to allocate a bandwidth. Thereafter, the bandwidth broker sets border routers of an inter-domain and cooperates with the adjacent domains regarding a bandwidth reservation.  
         [0018]     According to these prior arts, since only a resource allocation device is used to provide a differentiated service, it is not easy to perform a fast path information discovery processing and it cannot provide a differentiated service efficiently.  
         [0019]     The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore, it should be understood that the above information may contain information that does not form the prior art that is already known in this country to a person or ordinary skill in the art.  
       SUMMARY OF THE INVENTION  
       [0020]     The present invention has been made in an effort to provide a resource allocation device and a method thereof having advantages of performing fast path information retrieval and providing differentiated services efficiently.  
         [0021]     An exemplary resource allocation device according to an embodiment of the present invention includes a database, a resource allocation management unit, a service level agreement unit, a routing information management unit, and a policy control management unit.  
         [0022]     The database concerns user and service information.  
         [0023]     The resource allocation management unit is for determining whether a service request agrees with a service level agreement and whether it accepts/rejects a resource allocation request using available resource information of a path connecting a beginning point with an end point, on receiving the service request of a user.  
         [0024]     The service level agreement unit is for negotiating the service level agreement with the user before receiving the service request, sending the received service request to the resource allocation management unit, acquiring the result of the resource allocation request and transmitting the result of the resource allocation request to the user.  
         [0025]     The routing information management unit is for obtaining a network configuring information, storing the network configuring information in the database, discovering the path to provide the service, and storing the discovered path in the database to be reused.  
         [0026]     The policy control management unit is for deciding a policy according to whether the service request and the resource allocation request are accepted.  
         [0027]     In a further embodiment, a resource allocation method for providing differentiated service includes the following steps: receiving a service request from a user, determining whether a resource can be allocated to provide the requested service, obtaining routing information from routers composing a differentiated service, searching, discovering, and storing path information using the obtained routing information, transmitting a determined policy to real routers; and allocating a resource according to the determined policy.  
         [0028]     According to an exemplary embodiment of the present invention, it is determined that the service request can be supported and the result of the service request allows a resource to really allocate so that the differentiated service can be provided efficiently. Also, in the path information acquisition processing, the path information search can be quickly implemented by using the storage device so that the developed commercialization model of the differentiated service can be applied. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]      FIG. 1  is a general schematic diagram of a network capable of providing differentiated services.  
         [0030]      FIG. 2  is a schematic diagram of a network capable of providing a differentiated service according to an exemplary embodiment of the present invention, wherein a bandwidth broker is used as a resource allocation device.  
         [0031]      FIG. 3  is a schematic diagram of a bandwidth broker used as a resource allocation device according to an exemplary embodiment of the present invention.  
         [0032]      FIG. 4A  to  FIG. 4C  respectively are a flowchart illustrating a resource allocation processing according to an exemplary embodiment of the present invention.  
         [0033]      FIG. 5  is a flowchart illustrating a service level agreement processing for allocating a resource according to an exemplary embodiment of the present invention.  
         [0034]      FIG. 6  is a detailed flowchart illustrating the service request processing of  FIG. 5 .  
         [0035]      FIG. 7  is a detailed flowchart illustrating a path discovery processing among the service request processing of  FIG. 6 . 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0036]     An embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.  
         [0037]     In the following detailed description, only the preferred embodiment of the invention has been shown and described, simply by way of illustration of the best mode contemplated by the inventor(s) of carrying out the invention. As will be known, the invention is capable of modification in various obvious respects, all without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not restrictive. To clarify the present invention, parts which are not described in the specification are omitted, and parts for which similar descriptions are provided have the same reference numerals.  
         [0038]      FIG. 1  is a general schematic diagram of a network capable of providing a differentiated service. Referring to  FIG.1 , terminal devices  110  and  140 , and Internet service provider networks  120  and  130  are illustrated. The Internet service provider networks  120  and  130  include border routers  121   a,    121   b,    131   a,  and  131   b,  and inner routers  122   a,    122   b,    132   a,  and  132   b.    
         [0039]     The terminal devices  110  and  140  are provided at ends of the network and may be, for example, a user terminal, a client, or a server. The terminal devices  110  and  140  perform a communication so as to apply a differentiated service and the Internet service provider networks  120  and  130  provide a requested service to the terminal devices  110  and  140 .  
         [0040]     The border routers  121   a  and  121   b  are provided in the first Internet service provider network  120  and are coupled with the second Internet service network  130 , as well as with the terminal device  110 .  
         [0041]     Likewise, the border routers  131   a  and  131   b  are provided in the second Internet service provider network  130  and are coupled with the first Internet service network  120 , as well as with the terminal device  140 .  
         [0042]     Also, the border routers  121   a,    121   b,    131   a,  and  131   b  may mark a (DSCP) according to the Service Level Specification (SLS). The Internet service provider networks  120  and  130  include inner routers  122   a,    122   b,    132   a,  and  132   b,  as well as the border routers  121   a,    121   b,    131   a,  and  131   b,  therein. The inner routers  122   a,    122   b,    132   a,  and  132   b  decide which service is provided to a flow marked by the border routers  121   a,    121   b,    131   a,  and  131   b  and provide the corresponding service.  
         [0043]      FIG. 2  is schematic diagram of a network to provide a differentiated service using a bandwidth broker according to an exemplary embodiment of the present invention.  
         [0044]     Referring to  FIG. 2 , first and second bandwidth brokers  230  and  250  are added to first and second Internet service provider networks  220  and  240  ( 120  and  130  in  FIG. 1 ). The first and second bandwidth brokers  230  and  250  function as resource allocation devices.  
         [0045]     In detail, when the first and second user terminal devices  210  and  260  request a specified service, the bandwidth brokers  230  and  250  determine whether the particular service agrees with a service level agreement, where the service level agreement is a service contract negotiated previously between a user and a service provider. When the service agree with the service level agreement, the bandwidth brokers  230  and  250  allocate a policy for providing the service to border routers  221   a,    221   b,    241   a,  and  241   b.    
         [0046]     When the first bandwidth broker  230  manages one domain, thereby needing another domain to support the requested service, the adjacent second bandwidth broker  250  provides the requested service according to the service level agreement. Likewise, when the second bandwidth broker  250  manages one domain, thereby needing another domain to support the requested service, the adjacent first bandwidth broker  230  provides the requested service according to the service level agreement.  
         [0047]      FIG. 3  is a schematic diagram of a bandwidth broker according to an exemplary embodiment of the present invention.  
         [0048]     Referring to  FIG. 3 , a bandwidth broker  310 , according to an exemplary embodiment of the present invention, includes a data base management unit  311 , a monitoring information management unit  312 , a service level agreement unit  313 , a routing information management unit  314 , a policy controlling management unit  315 , a resource allocation management unit  316 , a common open policy service (COPS) stack management unit  317 , an instruction interface  318 , and a service level agreement stack management unit  319 . Also, a periphery device  320  includes a secondary policy-based router unit  321 , a service level agreement unit  322  of the adjacent bandwidth broker, and a service level agreement unit  323  of a client, which is linked to the first bandwidth broker  310 . Elements of the bandwidth broker  310  and a connection relation thereof with the peripheral device  320  according to an exemplary embodiment of the present invention shown in  FIG. 3  are described later referring to  FIG. 4A  through  FIG. 4C .  
         [0049]     The database management unit  311  manages all data requested by the bandwidth broker  310  so as to process a resource allocation request. That is, the database management unit  311  manages a bandwidth broker construction information database, a routing information database, a service information database, an admission control information database, a policy information database, and a SNMP, MIB, or PIB information database.  
         [0050]     The database stores information concerning a user and a service for providing a differentiated service, that is, user information, service information required by the user, service level agreement information between the user and the provider, router information, and network configuring information acquired by a router, and path information configured to provide an end to end service.  
         [0051]     The monitoring information management unit  312  processes the monitoring information provided by the router.  
         [0052]     The service level agreement unit  313  performs a service level agreement of the bandwidth broker  310  in domain, as well as a service level agreement between bandwidth brokers in domain to domain communication. For example, the service level agreement unit  313  and the service level agreement stack management unit  319  perform the service level agreement with the user, send the received service request to the resource allocation management unit, acquire the result concerning the resource allocation request, and transmit the result to the user.  
         [0053]     The routing information management unit  314  manages and collects routing information, which is used when the bandwidth broker  310  allocates policy in a differentiated service domain. In detail, in order to provide the differentiated service, the routing information management unit  314  collects network configuring information and stores the same in the database. For example, the routing information management unit  314  collects routing tables of the routers using SNMP, stores the collected routing tables to the database, discovers a path connecting a beginning point with an end point, and stores the discovered path to the database to be reused.  
         [0054]     The policy control management unit  315  decides a policy using a Common Open Policy Service-Policy Provisioning (COPS-PR) interface such that the router interface uses the policy to provide the differentiated service. The policy control management unit  315  decides the policy according to whether the service request and the resource allocation request are admitted.  
         [0055]     The resource allocation management unit  316  determines available resource information and a resource allocation possibility, and acknowledges the result when client, server, or adjacent bandwidth broker request a resource allocation. The resource allocation management unit  316  determines whether the service request is consistent with the service level agreement and whether to accept the resource allocation request by using the available resource information of the path connecting the beginning point with the end point, when the service request is received by the user.  
         [0056]     The COPS stack management unit  317  encodes/decodes COPS or COPS-PR in order to receive data from the border routers and transmit data to the same.  
         [0057]     The instruction interface unit  318  makes a common line interface (CLI) of the corresponding device when it does not use the COPS protocol. Through the CLI configured in this manner, the policy delivered from the bandwidth broker  310  is applicable to the router.  
         [0058]     The service level agreement stacks management unit  319  functions in encoding and decoding the service level agreement protocol inputted from the client, the server, or the adjacent bandwidth broker.  
         [0059]      FIG. 4A  to  FIG. 4C  show a resource allocation processing of a bandwidth broker  310  according to an exemplary embodiment of the present invention, the bandwidth broker having the same construction as shown in  FIG. 3 , wherein the elements of the bandwidth broker  310  allocate a resource according to the following.  
         [0060]     Referring to  FIG. 4A , a policy request processing of the router and a policy delivery processing of the bandwidth broker  310  are shown by the steps S 411  to S 414 .  
         [0061]     In detail, the policy-based router unit  321  sends the construction information and the policy request to the policy control management unit  315  (S 411 ), the policy control management unit  315  sends a DB query to the database management unit  311  (S 412 ) and gains the desired information, that is, the DB result (S 413 ). And then, the policy control management unit  315  sends the policy decided on, based on such information, to the policy-based router unit  321  (S 414 ), thereby applying the policy for the real operation of the router.  
         [0062]     Referring to  FIG. 4B , a service level agreement processing and a resource allocation request processing are shown by the steps S 421  to S 430 .  
         [0063]     In detail, the client service level agreement unit  323  of the terminal device requests the service level agreement and the resource allocation to the service level agreement unit  313  (S 421 ). And then, the resource allocation request is delivered to the resource allocation management unit  316  (S 422 ).  
         [0064]     Thereafter, the end to end path information, that is, the information of the routers provided in the path connecting the source with the destination, is required so as to decide the resource allocation possibility, and thus the resource allocation management unit  316  queries the routing table to the routing information management unit  314  (S 423 ) and obtains the result thereof (S 424 ).  
         [0065]     After a path discovery processing, in the case that the destination domain is different from the departure domain, the current bandwidth broker  310  should request the resource allocation to the adjacent bandwidth broker. Accordingly, the resource allocation management unit  316  sends a resource allocation request of the adjacent bandwidth broker to the service level agreement unit  313  (S 425 ). This is again transmitted to the bandwidth broker service level agreement unit  322  (S 426 ) and the bandwidth broker service level agreement unit  322  acknowledges the result of the processing (S 427 ).  
         [0066]     Next, the service level agreement unit  313  informs the result of the resource allocation request delivered from the adjacent bandwidth broker to the resource allocation management unit  316  (S 428 ) and the resource allocation management unit  316  decides the real resource allocation possibility using the information.  
         [0067]     As a result, the acknowledgement for the real resource allocation possibility is delivered to the service level agreement unit  313  (S 429 ), and successively to the client service level agreement unit  323  (S 430 ).  
         [0068]     Referring to  FIG. 4C , a processing to request resource allocation really according to the resource allocation is shown by the steps S 431  to S 438 .  
         [0069]     In detail, when the bandwidth broker  310  decides to accept the resource allocation possibility, the resource allocation management unit  316  requests the resource allocation of the real router to the policy control management unit  315  (S 431 ). To this end, the acquisition of the end to end path information is required and the routing table is queried by the routing information management unit  314  (S 432 ), and the result thereof should be sent to the policy control management unit  315  (S 433 ).  
         [0070]     When no necessary path information is stored, the router information management unit  314  requests a routing information acquisition to the instruction interface  318  (S 434 ) and obtains the routing information (S 435 ). And then the instruction interface  318  requests the routing information to the policy-based router  321  using SNMP (S 436 ) and obtains the necessary information (S 437 ).  
         [0071]     Accordingly, through the obtained routing information, the policy control management unit  315  discovers the end to end path and sends a new policy to the policy based router unit  321  (S 438 ), and finally, the resource allocation is performed.  
         [0072]      FIG. 5  is a flowchart of service level agreement processing for a resource allocation in a bandwidth broker according to an exemplary embodiment of the present invention.  
         [0073]     Referring to  FIG. 5 , the bandwidth broker  310  receives messages for the service level agreement and the resource allocation request from the user (S 510 ). The received service request message includes session information concerning the requested service, and the session information includes provider information, receiver information, and desired resource level, etc. Next, the received session information is stored in a session information database (S 520 ), and thereafter, is used to apply the specified policy concerning the specified flow for the routers. Then, the bandwidth broker  310  receives the service request and decides to accept the current request service, that is, the resource allocation request (S 530 ). According to an exemplary embodiment of the present invention, the bandwidth broker  310  receives the service request for the resource allocation and decides to accept the service request. This depends on the available resource status of the current network and the service level agreement negotiated between the provider and the user. When the requested service agrees with the service level agreement and the amount of available resource is larger than that of the requested resource, the resource allocation is decided to be possible and the requested service is accepted. On the other hand, when the requested service does not agree with the service level agreement and the amount of available resource is smaller than that of the requested resource, the resource allocation is decided to be rejected and the request service is rejected.  
         [0074]     A detailed decision processing of the resource allocation request is described later with reference to  FIG. 6 .  
         [0075]     Thereafter, when it is decided to accept the resource allocation, the bandwidth broker  310  generates an accept message (S 540 ). The accept message is sent to the user terminal and the user receives the result of the service request (S 560 ) thereby receiving the requested service according to the agreement.  
         [0076]     When it is decided to reject the resource allocation, the bandwidth broker  310  generates a reject message (S 550 ). The reject message is also sent to the user terminal and the user receives the result of the service request (S 560 ) and recognizes the same so that the user requests a lower leveled service or ends the service request.  
         [0077]     Meanwhile,  FIG. 6  is a detailed flowchart for implementing a service request processing method of  FIG. 5 .  
         [0078]     To implement the above-noted resource allocation request processing (S 530 ), that is, to decide whether the resource allocation request is accepted, first, the end to end path of the terminals is discovered to be utilized for the resource allocation.  
         [0079]     For discovering the end to end path, the prior art uses the source and destination information, but an exemplary embodiment of the present invention uses a beginning point defined by a border router of a domain including source and an end point defined by a border router of a domain including destination. The route for connecting between the beginning point and the end point is called a Path.  
         [0080]     The beginning point and the end point are designed to store the path information and to reuse the same. At this time, terminals of a same source domain have the same beginning point, and terminals of a same destination domain have the same end point. Accordingly, when different flows have the same beginning point and the same end point, regardless of a different source value and destination value, the service is provided through the same path. Therefore, the path information can be stored using the beginning point and end point, and the stored path information can be used. Thus, the path can be quickly discovered and resource can be saved.  
         [0081]     In detail, referring to  FIG. 6 , the resource allocation request processing is started by searching the beginning and end points (S 531 ).  
         [0082]     By the result of the searching, it is decided whether path information having the same beginning point and the same end point is stored in the path information storage device (S 532 ), and if so, it is decided whether the path has sufficient resources to accept the resource allocation (S 534 ).  
         [0083]     When no path information is stored in the path information storage device, a new path is discovered through the path discovery processing (S 533 ). The new path discovery processing is described later with reference to  FIG. 7 .  
         [0084]     When it is decided to accept the resource allocation, the acceptance message thereof is transmitted to the user (S 535 ). Also, when it is decided to reject the resource allocation, the reject message thereof is acknowledged to the user (S 536 ).  
         [0085]     After the result of the service request acceptance is transmitted, that is, the service request is accepted, the real policy should be sent to the routers. Thus, the real policy is configured according to the service request (S 537 ) and the policy information is transmitted to the router (S 538 ), thereby providing the desired service.  
         [0086]     Meanwhile,  FIG. 7  is a flowchart showing path discovery processing among service request processing of the resource allocation device of  FIG. 6 .  
         [0087]     As above noted referring to  FIG. 6 , when corresponding path information is not acquired by searching the path storage device using the beginning point and end point, the bandwidth router performs a new path discovery process (S 533 ).  
         [0088]     In the further path discovery processing, the routing table information of the beginning point routers is searched (S 533 - 1 ). At this time, because the routing table information etc., including the beginning routers is obtained by using SNMP, the value stored in the database can be used simply.  
         [0089]     After the routing table information is acquired, matching values are searched from the entry value of the routing table information wherein the matching value represents that the router is corresponding to a Destination Hop including the terminal of the destination (S 533 - 2 ). For example, it is decided whether the matched routing information is a default gateway by inputting each entry value in a simple numerical formula (not shown).  
         [0090]     When the matching routing information is the default gateway, meaning that the current domain does not include the destination, the adjacent bandwidth broker is requested to perform the resource allocation request (S 5334 ).  
         [0091]     When the matching routing information is not the default gateway, meaning that a router corresponding to the next hop of the matching routing information is on the path, the path information is stored in the database (S 533 - 3 ).  
         [0092]     Next, it is checked whether the routing information matching the formula is directly or substantially connected to the destination (S 533 - 5 ). On being directly connected to the destination, as a destination Hop, the path discovery processing is finished.  
         [0093]     When it is found that the routing information matching the formula is not directly connected, the routing table information of the router of the next Hop is searched (S 533 - 6 ) and the steps S 533 - 2  to S 533 - 6  described above are repeated until the destination Hop is searched.  
         [0094]     Referring to FIGS.  5  to  7 , in order to discover the desired path for connecting the source with the destination in the resource allocation processing according to an exemplary embodiment of the present invention, the source and destination information itself is not used, rather the beginning point, defined as a border router of a domain including a source, and the end point, defined as a border router of a domain including a destination, are used as the representative values of the source and destination located in the same domain. Also, after the path discovery processing, the path information is stored in a database and the pre-stored path information is reused as the path information through searching.  
         [0095]     According to an exemplary embodiment of the present invention, the pre-stored path information having the same beginning and end point can be utilized to provide the service through the same path using the beginning point, defined as a border router of a domain including a source, and the end point, defined as a border router of a domain including a destination. Also, the resource allocation can be achieved efficiently by using the path storage device.  
         [0096]     While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.  
         [0097]     According to an exemplary embodiment of the present invention, it is determined if the service request can be supported and the result of the service request allows a resource to really allocate so that the differentiated service can be provided efficiently. Also, in the path information acquisition processing, the path information search can be quickly implemented by using a storage device so that the developed commercialization model of the differentiated service can be applied.