JP3968066B2 - Name resolution system - Google Patents

Description

  The present invention is a name resolution system that provides an address or identifier of a target resource according to access from a user for a plurality of resources that are distributed and managed on a network. In particular, the present invention can flexibly deal with a ubiquitous service and The present invention relates to a name resolution system that can selectively use a name space and a name resolution mechanism.

  In a system that uses resources such as files over a network, a name resolution mechanism that gives a "name" such as a file name and responds with the address of the resource location corresponding to the "name" It is considered to occupy a very important position. By using the name and name resolution system, the user can use the target resource without knowing the actual network address as long as the name of the resource is stored. An apparatus that actually performs name resolution in the system is called a resolver.

  Among the name resolution mechanisms, the most well known at present is the Internet DNS (Domain Name System). In this system, when a fully qualified domain name (FQDN) included in a mail address or URL is given as a “name”, the corresponding IP address is returned. DNS utilizes the fact that domains constituting FQDNs are hierarchized, and the resolver configuration is also hierarchized. For this reason, even if the scale of the system increases, name resolution can be executed relatively efficiently. However, if the name space is not in a hierarchical structure, a problem arises in application.

Research results called CAN (Content Addressable Network) as a mechanism that works efficiently even when the scale is increased by performing name resolution for a general namespace under a horizontally distributed resolver configuration (For example, refer nonpatent literature 1) and the research result called Chord (for example, refer nonpatent literature 2) were announced. These mechanisms are techniques for mechanically performing name space division and name resolution distribution processing by converting a name into a hash key using a hash function. In CAN and Chord, unlike DNS, the network between resolvers is built ad hoc and can flexibly cope with the increase in the number of user terminals that use the system. In order for a user terminal to use CAN or Chord, it is necessary to know one active resolver as an entry point, but since the resolver configuration is an ad hoc network, the connection of each resolver to the system is intermittent. It is difficult to specify entry points fixedly.

The ubiquitous service, which can be a major service in the future information distribution network, is a service that enables information distribution “anytime, anywhere, with anyone” that transcends spatial constraints. Compatible communication services include a wide range of service concepts that vary considerably in content. For example, (1) managing, grasping or using the location and state of an object or person (for example, whether it is in stock) by attaching a wireless tag to an object or person and installing a wireless tag reader in various places And (2) sensing services that provide various applications based on various sensing information sent from those sensors. In realizing these ubiquitous services, host names and file names that are currently commonly used as names do not include information on the resources themselves, and it is difficult to grasp the correspondence between the names and the resources. The sensing service will be exemplified as a suitable name for the ubiquitous service. When it is desired to obtain specific sensing information, a self-descriptive name expressing what kind of sensing information is desirable, for example, (sensing item name, sensing location, sensing time) may be used as the name.
Obtaining the address of the sensor having the same information or the address of the database storing the sensor information from the name is the name resolution.

  The MIT research result called INS <Intentional Naming System> (for example, see Non-Patent Document 3) is a system that performs name resolution based on self-explanatory names. The name is composed of a plurality of attributes and their values having a dependency relationship with each other, and the dependency relationship is represented by a tree structure. As with CAN and Chord, INS is also an ad hoc network with a resolver configuration. However, INS provides a bootstrap server that manages a list of active resolvers as a fixed entry point. In addition, as a name resolution related technology in the ubiquitous service, logistics management such as Auto-ID center concept (for example, Non-Patent Document 4) and ubiquitous ID (for example, Non-Patent Document 5) is the main management target. In some cases, it is expected that the name is expressed by a code in a fixed format, and a fixed resolver network is formed to ensure the scale property.

  The name space is divided into semantics (semantics) for a huge number of resources, and a name resolution mechanism with the same configuration as DNS is constructed for each part of the divided name space, and the user terminal becomes the target resource. A research result of a mechanism for selectively using a name resolution mechanism according to corresponding semantics (for example, see Non-Patent Document 6) was announced. In addition, research results of a mechanism for automatically discovering an appropriate resolver in response to a user request by allowing a user terminal to autonomously grasp the location and availability of a resolver (name server) in DNS (Non-patent Document 7) Reference) was announced.

S. Ratnasamy, P. Francis, M. Handley, R. Karp, and S. Shenker, “A scalable content-addressable network,” In Proc. Of ACM SIGCOMM '01 Aug. 2001. I. Stoica, R. Morris, D. Karger, M. F. Kaashoek, and H. Balakrishnan, “Chord: A scalable peer-to-peer lookup service for internet applications,“ In Proc. Of the ACM SIGCOMM2001, Aug.2001. W. Adjie-Winoto, E. Schwartz, H. Balakrishnan and J. Lilley, “The Design and implementation of an intentional naming system,” In Proc. Of the 17th ACM Symposium on Operating Systems, Dec. 1999. http://www.autoidcenter.org/main.asp http://udicenter.org Hirofumi Denho, Hideaki Tani, Name Resolution in Ubiquitous Environment, “2003 IEICE General Conference B-7-6, Mar. 2003. Tatsuya Yamada, Yujiro Shimada, Hiroshi Eiko, “Problems of Name Resolution in Ubiquitous Networks and Proposal of Solutions,” Multimedia, Distributed, Cooperation and Mobile (DICOMO2003) Symposium, June2003.

  For names used in future information distribution networks, including ubiquitous services, multiple types of name spaces and name resolution mechanisms are used due to differences in requirements and historical background. It is predicted that these multiple name spaces and name resolution mechanisms will be used properly. If the number of name spaces and name resolution mechanisms is fixed and small, it is possible for the user terminal to directly grasp the entry points of each name resolution mechanism, but in the future, targeting a wide variety of resources Many namespaces and name resolution mechanisms are built and may include ad hoc mechanisms in which entry points are dynamically changed.

In such an environment, it is difficult to manage information such as entry points required for using each name space and name resolution mechanism on the user terminal side, which is caused by the appearance and disappearance of resolvers. A mechanism for performing name resolution without making the user terminal aware of the dynamic change of the entry point is required.
Similarly, it is difficult for the resource (to be exact, the terminal or device that owns the resource) to know the entry point of the individual name resolution mechanism that should register or change the combination of name and address. It is desirable to have an environment that does not make resources aware of dynamic changes in points.
In addition, in order to improve the descriptiveness of the name in order to improve the convenience of the user, the user can specify a resource by a name combining a plurality of name spaces, and such a complicated name is assigned to each name space or There is also a need for a service that works in conjunction with the name resolution mechanism.
Research results on multiple name resolution mechanisms or mechanisms for using different entry points have already been published, but these include dynamic changes to the name resolution mechanism's entry points and name resolution that combines multiple name spaces. Is not assumed.

An object of the present invention is to provide a name resolution system that can flexibly cope with a ubiquitous service and can use a plurality of name spaces and name resolution mechanisms.
Another object of the present invention is to provide a name resolution system that can flexibly cope with the case where a large number of name spaces and name resolution mechanisms are constructed and entry points of the name resolution mechanism are dynamically changed.
Furthermore, another object of the present invention is to realize a name resolution system in which a plurality of name resolution mechanisms can cooperate in name resolution even when a resource is specified using a name obtained by combining a plurality of name spaces. There is.

The name resolution system according to the present invention is a name resolution system that provides an address of a target resource to a user according to access from the user for resources managed in a distributed manner on the network.
Consists of one or more resolvers that are connected to the network and have resource address information that defines the relationship between the resource identification information and the resource address specified by the resource identification information, and at least one entry point is specified Multiple name resolution mechanisms,
One or more intermediary devices connected to the plurality of name resolution mechanisms and user terminals via the network, receiving name resolution requests sent from the user terminals, and transferring them to the entry points of the corresponding name resolution mechanisms And
The intermediary device extracts a name for specifying a resource from the resource identification information included in the received name resolution request and name space identification information to which the name belongs or identification information of a name resolution mechanism for performing name resolution; Storage means for storing the relationship between the information and the identification information of the name resolution mechanism that performs name resolution for the name included in the name space, and received when receiving the name resolution request sent from the user terminal A related name resolution mechanism is obtained from the resource identification information included in the name resolution request, and the name resolution request is transferred to the entry point of the obtained name resolution mechanism.
The entry point that receives the name resolution request transfers the name resolution request to the resolver included in the name resolution mechanism,
The resolver of the name resolution mechanism that has received the name resolution request obtains the address of the resource from the name identification information that specifies the resource included in the name resolution request, and sends the obtained resource address to the intermediary device via the entry point. It transmits, and it returns to a user terminal from a mediation apparatus, It is characterized by the above-mentioned.

  In the name resolution system according to the present invention, an intermediary device is connected via a network between a user terminal and a plurality of name resolution mechanisms. Therefore, a name resolution request from a user terminal is handled by the mediation device. A mechanism is selected, and it is possible to flexibly cope with a plurality of name spaces and a plurality of name resolution mechanisms. In particular, since a plurality of name resolution mechanisms having different formats can cooperate with each other, name resolution can be executed more efficiently.

  In a preferred embodiment of the name resolution system according to the present invention, the resource identification information of the name resolution request transmitted from the user terminal to the mediation device includes only the name that identifies the target resource, and the mediation device identifies the resource. Means for identifying or discriminating the identification information of the namespace to which the name belongs from the name to be transferred, and transferring the name resolution request to the entry point of the corresponding name resolution mechanism based on the obtained namespace identification information. Features. As described above, the mediation device has means for determining or extracting the name space to which the name belongs from the name information, so that the mediation device specifies the resource identification information included in the name resolution request sent from the user. Extracts the corresponding namespace from the name even if it contains only the name, forwards the name resolution request to the corresponding name resolution mechanism, and if both the name and namespace are included, the corresponding name resolution based on the namespace The name resolution request can be forwarded to the mechanism entry point. As a result, the user can know the address managed on the network of the resource from only the name of the target resource without knowing the name space.

  In a preferred embodiment of the name resolution system according to the present invention, the pre-resolution mechanism has means for dynamically changing the entry point, and when the entry point is changed, the intermediary device connected to the name resolution mechanism. Entry point change information is transmitted. As described above, in the case of a name resolution system that allows entry points to be dynamically changed, it is possible to flexibly cope with a case where a large number of name spaces and name resolution systems are newly constructed after the system is constructed. In particular, even when a new resolver appears or an existing resolver disappears, name resolution can be executed without making the user terminal aware of dynamic entry point changes.

  In another preferred embodiment of the name resolution system according to the present invention, the resource identification information included in the name resolution request transmitted from the user terminal to the intermediary device is represented by a logical expression including name information belonging to a plurality of name spaces, The intermediary device forwards the name resolution request to an entry point of each name resolution mechanism corresponding to each name space, and performs a set operation process on the address sent from each name resolution mechanism. . In this example, even if the name that specifies the resource is represented by a logical expression that spans multiple name spaces, the intermediary device forwards the name resolution request to the name resolution mechanism corresponding to each name space. Since the set operation processing is executed for each address, the best name resolution result can be obtained.

The present invention can facilitate the selective use and utilization of name spaces and individual name resolution mechanisms that may appear in the future reflecting the diversification of resources.
By meta-organizing the namespace and individual name resolution mechanism by ID, name resolution is performed without making the user aware of the existence of the individual name resolution mechanism in some cases, dynamically changing the entry point of the individual name resolution mechanism. Realize the environment. In addition, as described in the first embodiment, by providing a NAT device that redirects communication between the user terminal and the entry point to the mediation device, an environment that transparently provides the broker function to the user terminal is realized. Is also possible.
Furthermore, not only the name resolution request from the user terminal, but also the name and address registration / change request from the resource (more precisely, the terminal / device holding the resource) It is possible to realize an environment that executes without being aware of specific changes.
Furthermore, name resolution that combines multiple name spaces is enabled.

FIG. 1 is a diagram showing an example of a name resolution system according to the present invention. On the data communication network 100 such as the Internet, a name resolution mechanism that uses a plurality of individual name resolution mechanisms is constructed. In FIG. 1, reference numeral 101 denotes an entire name resolution mechanism, and the name resolution mechanism 101 according to the present invention includes a plurality of individual name resolution mechanisms of the same system or different systems, and in this example, two name resolution mechanisms 201 and 202. With For example, DNS can be used as the individual name resolution mechanism 201 and INS can be used as the name resolution mechanism 202. Each name resolution mechanism 201 and 202 has one or more name resolution devices (resolvers) and one or more entry points, respectively. Therefore, each name resolution mechanism can be interpreted as a resolver network in which entry points are designated. Here, reference numeral 301 denotes an entry point (name server) of the DNS 201, and reference numeral 302 denotes an entry point (bootstrap server) of the INS 202. A plurality of user terminals 501 are connected to the network 100, and these user terminals may be personal computers having a communication function, for example. The name resolution request access from each user terminal is transmitted to the broker 701 functioning as an intermediary device for name resolution via the network 100, and the broker 701 selects a name resolution mechanism corresponding to the name space included in the access, Transferred to the entry point of the selected name resolution mechanism. Further, the address of the resource that is a response to the name resolution request from the name resolution mechanism 201 or 202 is transferred to the user terminal via the broker 701.
Note that only two individual name resolution mechanisms have been shown for the sake of clarity, but of course, application to a name resolution mechanism having three or more individual name resolution mechanisms is possible. Further, although only one entry point and broker of the individual name resolution mechanism are shown, each name resolution mechanism can also specify a plurality of entry points. Furthermore, in this example, only a single broker 701 is provided, but it is also possible to have a plurality of brokers.

  In this example, it is assumed that the name resolution mechanisms 201 and 202 have one server designated as an entry point and a plurality of resolvers connected via a network. Each resolver has address information that defines the relationship between name identification information that specifies a resource and the address of the resource, and is based on the name identification information included in the name resolution request when the name resolution request is received from the entry point. The corresponding resource address is retrieved and the result is returned to the entry point. Each resolver transfers the name resolution request to another resolver when the corresponding address cannot be retrieved, and the other resolver executes name resolution. Each resolver can be connected to the name resolution mechanism in an ad hoc manner. When a dynamic change is made, such as when the resolver disappears or becomes a new resolver, these resolvers are used. Address information is transmitted to the entry point and managed at the entry point.

  FIG. 2 is a diagram showing a configuration of an example of a user terminal and a broker. First, the user terminal will be described. Two programs are installed in the user terminal 501. The first program sends a name resolution request containing the name of the target resource and the name space corresponding to that name or the name resolution mechanism identification information (ID) that resolves the name as resource identification information to any broker. The second program is a program 602 that receives an address corresponding to a target resource from the broker 701. The program 601 is activated by the user, and when the user inputs the name of the target resource and the ID of the name resolution mechanism, the program 601 transmits these pieces of information to an arbitrary broker, activates the program 602, and ends. Note that the first program is also applied to a case where only the name information specifying the target resource is included without including the name space.

  When the name resolution mechanism is DNS, the user can use the domain name of the host storing the resource as the identification information of the name that designates the resource, and use the format that displays the domain name as the name space. That is, the namespace can be understood as a collection of names. Further, as an ID for identifying a name space, for example, a URI (Uniform Resource Identifier) used for identifying a document in a Web service can be used. As the ID of the individual name resolution mechanism, for example, the address of a server constituting an entry point such as a bootstrap server can be used.

  In the present invention, since the broker 701 is interposed between the user terminal and the name resolution mechanism, and the broker has information regarding the entry point of each name resolution mechanism, the entry point assumed by the user terminal and the entry point actually in operation Need not match, and the user does not need to know the address of the name resolution mechanism entry point. Therefore, the entry point used as the ID of the individual name resolution mechanism may be a virtual existence, and it is not necessary to prepare any device corresponding to the address. Although the name or address corresponding to the broker is used for the destination of the name and ID, the IPv6 well-known common to all brokers even if the name (for example, DNS FQDN) or fixed address assigned to each broker is used. You may use -site-local-unicast address. In the former case, the address of an arbitrary (usually nearest) broker is stored in advance in the user terminal. As a method of transmitting the name and ID from the user terminal to the broker, the name and ID may be transmitted in one communication message or divided into two messages. In the former case, the communication message can be described in a highly descriptive language such as XML. Also, when the ID of the individual name resolution mechanism is used as the address of the entry point, the name resolution sent directly from the user terminal to the entry point is similar to transparent caching, which is a type of connection control to the web cache server. It is also possible to redirect the request with a Network Address Translation (NAT) device so that the name and ID combination is made “transparent” to the user terminal to the broker. At this time, the NAT device appears as a user terminal from the broker, and the NAT device appears as an entry point from the user terminal (the NAT device transmits the reply from the broker as if it were an answer from the entry point). Note that the program 602 ends when it receives an address (sometimes an address group) from the broker to which the program 601 has sent its name and ID.

  Next, entry points of each name resolution mechanism will be described. The name resolution mechanism (DNS) entry point 301 includes two programs. The first program is a program 401 for dynamically reselecting a resolver or bootstrap server designated as an entry point, and the second program is a program 402 for notifying an arbitrary broker of a change of an entry point. The name resolution system according to the present invention can flexibly cope with a ubiquitous service, and the entry point of the name resolution mechanism can be changed. When the entry point is changed, the change information is transmitted to the broker, and the broker manages the entry point of each name resolution mechanism.

  Next, the configuration of the broker (mediation device) will be described. As an example, nine programs can be installed in the broker 701. The first program is a program 801 that manages a list of addresses of resolvers or bootstrap servers specified as entry points when accessing each individual name resolution mechanism. The second program is a program 802 that manages information that defines the correspondence between IDs that identify name spaces and IDs that identify individual name resolution mechanisms. The third program is a program 803 that receives the name identification information of the target resource and the ID of the name space or individual name resolution mechanism corresponding to the name from the user terminal. The fourth program is a program 804 that selects an entry point that matches the ID of the name space or individual name resolution mechanism received from the user terminal. The fifth program is a program 805 that transfers a request for resolving the name received from the user terminal to the entry point of the individual name resolution mechanism. The sixth program is a program 806 that receives an address corresponding to the target name transferred from the entry point. The seventh program is a program 807 for replying the address received from the entry point to the user terminal. The eighth program is a program 808 that receives a notification from the resolver or the bootstrap server and updates the list of entry points of each individual name resolution mechanism. The ninth program is a program 809 for notifying other brokers of entry point changes and sharing information among the brokers. In addition, in order to flexibly cope with the case where only the name information is included without including the name space as the resource identification information of the name resolution request transmitted from the user terminal, the corresponding name space is determined from the name identification information specifying the resource. A program to be extracted can be provided, and a program using the signature pattern matching method can be used as such a program. Here, with signature pattern matching, a character string or bit string peculiar to each name space is recorded in advance in a program, and pattern matching with a character string or bit string constituting a name included in the received resource identification information is performed. This is a technique for estimating the name space to which the name belongs. However, the application of signature matching is limited to the case where the name space can be uniquely specified by some character string or bit string.

  The program 801 and the program 802 are always activated, and respond with a list of entry points or ID information in response to a request from the program 804 described later. The program 803 is also always activated, waits for receiving a name and ID from the user terminal, starts the program 804, passes the received name and ID, and waits for reception from the user terminal again. The program 804 requests an entry point corresponding to the ID of the individual name resolution mechanism from the program 801, and when a plurality of corresponding entry points are answered, selects an appropriate entry point, passes this to the program 805, and ends. . When the ID passed from the program 803 is a name space ID, the program 804 requests the ID of the individual name resolution mechanism corresponding to the name space ID from the program 802 prior to the request to the program 801.

  The name space and the individual name resolution mechanism do not need to correspond one-to-one. The individual name resolution mechanism implementation method and the individual name resolution mechanism on the network that uses the method do not need to correspond one-to-one, and there may be a plurality of individual name resolution mechanisms that use the same method (particularly ad hoc resolvers). In the method of configuring the network between). Also, it is not necessary for each resource to be exclusively divided into individual name spaces or individual name resolution mechanisms. Information defining the correspondence between the name space and the individual name resolution mechanism in the program 802 is updated whenever a new name space or individual name resolution mechanism appears or when an existing name space or individual name resolution mechanism is discarded. . When new name spaces or individual name resolution mechanisms appear, IDs with guaranteed uniqueness are assigned to them. In addition, when a new type of individual name resolution mechanism appears, a procedure for processing name resolution requests and responses, a message format, and the like are externally stored in the broker. As a method of selecting an appropriate candidate from a plurality of entry points of the program 804, a simple round robin, a network distance (the number of hops and effective bandwidth), and an entry point capability / load (reaction speed and selection) Determination based on metrics such as stability (for example, the length of connection time to the system).

  The program 805 transfers the name resolution request received by the program 803 to the entry point passed from the program 804, starts the program 806, and ends. The program 806 waits to receive an address (sometimes an address group) from the entry point selected by the program 804, starts the program 807, passes the received address, and ends. The program 807 returns the address passed from the program 806 to the user terminal and ends.

  The program 808 is always activated, waits for the update notification of the entry point configured by the resolver or bootstrap server, updates the entry point list, starts the program 809, passes the content of the update notification and ends To do. The program 809 notifies the content of the update notification passed from the program 808 to other brokers via the network 100 and ends.

[Example 2]
FIG. 3 shows the configuration of a second embodiment of the broker and user terminal used in the name resolution system according to the present invention. The same components as those used in FIG. 2 will be described with the same reference numerals. The difference between the first embodiment and the second embodiment is the presence / absence of means for handling names composed of logical expressions of a plurality of conditions belonging to different name spaces.
The user terminal according to the second embodiment includes two programs, a program 611 similar to the program 601 according to the first embodiment and a program 602 according to the first embodiment. The program 611 is activated by the user and is input by the user and includes a name composed of logical expressions of a plurality of conditions belonging to a plurality of different name spaces and a name space corresponding to each condition constituting the name or an individual name resolution mechanism. The ID is transmitted to an arbitrary broker, and the program 612 is started and terminated. The communication message transmitted by the program 611 can be described in a highly descriptive language such as XML). An example of a communication message transmitted by the user terminal is shown in FIG.

  The broker of the second embodiment includes programs 801 and 802 of the first embodiment, a program 813 similar to the program 803 of the first embodiment, a program 814 similar to the program 804 of the first embodiment, and a program 805 of the first embodiment. The program 815 similar to the program 816, the program 816 similar to the program 806 of the first embodiment, the programs 807 to 809 of the first embodiment, and a name composed of logical expressions of a plurality of conditions belonging to different name spaces. 11 types of programs are installed: a program 810 that holds a logical expression that represents a relationship between conditions, and a program 811 that performs a set operation of an address group according to the logical expression.

  The program 813 is always started and waits for reception of a communication message from the user terminal. When the communication message includes a logical expression of a plurality of conditions, the program 810 is started and the communication message received from the user terminal is passed. If the received communication message is described by a single conditional expression, the program 814 is started, the communication message is passed, and the process is terminated.

  The program 810 decomposes the communication message into each condition constituting the name, a logical expression representing the relationship between them, and a name space corresponding to each condition or an ID of an individual name resolution mechanism, and a plurality of programs for each condition. 814 is started in parallel to pass the condition and ID, and further the program 811 is started to pass the logical expression and the degree of parallelism (the number of parallel executions) to finish.

  When the program 814 is started by the program 813, it executes the processing of the program 804 of the first embodiment. On the other hand, when it is started by the program 810, the processing of the program 804 of the first embodiment is executed and the program 815 is executed. Notify that it is parallel execution. The program 815 executes the processing of the program 805 of the first embodiment, and when the program 814 notifies that it is parallel execution, notifies the program 816 that it is parallel execution. The program 816 executes the processing of the program 806 of the first embodiment, and when the program 815 is notified that the program is executed in parallel, the received address is passed to the program 811 and ends. Otherwise, the program 807 is started. Then pass the received address and finish.

  The program 811 waits for an address to be passed from the program 816 executed in parallel for the number of parallelism, performs a set operation on the passed address group according to the logical expression passed from the program 810, and starts the program 807. Then pass the result of the set operation and finish. As the set operation processing, for example, AND or OR operation processing can be performed on addresses transferred from a plurality of name resolution mechanisms. For example, commonly appearing addresses are extracted when AND operation processing is performed, and all candidate addresses are output when OR operation processing is performed.

It is a diagram which shows an example of the name resolution system by this invention. It is a diagram which shows an example of a user terminal and a broker. It is a diagram which shows the structure of the user terminal and broker of 2nd Example. 6 is a diagram illustrating an example of a communication message transmitted by a user terminal in Embodiment 2. FIG.

Explanation of symbols

100 Network 101 Name Resolution Mechanism 301, 302 Entry Point 501 User Terminal 701 Broker

Claims (12)

For a resource that is distributed and managed on the network, in a name resolution system that provides the user with the address of the target resource according to the access from the user,
Consists of one or more resolvers that are connected to the network and have storage means for storing the relationship between the resource identification information and the resource address designated by the resource identification information, and at least one entry point is designated Multiple name resolution mechanisms,
One or more intermediary devices connected to the plurality of name resolution mechanisms and user terminals via the network, receiving name resolution requests sent from the user terminals, and transferring them to the entry points of the corresponding name resolution mechanisms And
The name resolution mechanism has means for dynamically changing an entry point, and when the entry point is changed, transmits the entry point change information to an intermediary device connected to the name resolution mechanism,
The intermediary device extracts a name for specifying a resource from the resource identification information included in the received name resolution request and name space identification information to which the name belongs or identification information of a name resolution mechanism for performing name resolution; Storage means for storing the relationship between the information and the identification information of the name resolution mechanism that performs name resolution for the name included in the name space, and received when receiving the name resolution request sent from the user terminal A related name resolution mechanism is obtained from the resource identification information included in the name resolution request, and the name resolution request is transferred to the entry point of the obtained name resolution mechanism.
The entry point that receives the name resolution request transfers the name resolution request to the resolver included in the name resolution mechanism,
The resolver of the name resolution mechanism that has received the name resolution request obtains the address of the resource from the name that specifies the resource included in the name resolution request, and transmits the obtained resource address to the mediation device via the entry point. , A name resolution system characterized by returning from the mediation device to the user terminal.   The name resolution system according to claim 1, wherein the resource identification information included in the name resolution request transmitted from the user terminal to the mediation device includes a name that specifies a target resource and name space identification information to which the name belongs. Or a name resolution system including identification information of a name resolution mechanism that performs name resolution.   The name resolution system according to claim 1, wherein resource identification information included in a name resolution request transmitted from the user terminal to an intermediary device includes only a name that specifies a target resource, Means for extracting the namespace identification information to which the name belongs from the name included in the resource identification information, and transfers the name resolution request to the entry point of the corresponding name resolution mechanism based on the obtained namespace identification information. Name resolution system characterized by that.   The name resolution system according to any one of claims 1 to 3, wherein the name space identification information is represented by a URI.   5. The name resolution system according to claim 1, wherein a server or a resolver is designated as the entry point, and the server or resolver designated as the entry point is a resolver included in the name resolution mechanism. A name resolution system comprising: address information, wherein when a name resolution request is received from an intermediary device, the name resolution request is transferred to the resolver based on the address information of the resolver held.   5. The name resolution system according to claim 1, wherein address information of an entry point of each name resolution mechanism is used as identification information of the name resolution mechanism. 7. The name resolution system according to claim 1 , wherein the intermediary device includes means for storing address information that defines a relationship between a name resolution mechanism and an address of an entry point thereof, and the name resolution system. A name resolution system, wherein the address information is updated when entry point change information is received from a mechanism. Name resolution system in name resolution system according to any one of claims 1 to 6, as the name resolution mechanism, and having a plurality of name resolution mechanism of different formats. 9. The name resolution system according to claim 8 , wherein the name resolution mechanism includes a domain name system (DNS) and an intentional naming system (INS). 10. The name resolution system according to claim 9 , further comprising: a name server as the DNS entry point, and a bootstrap server as the INS entry point.   The name resolution system according to claim 1, wherein the name resolution request transmitted from the user terminal to the mediation device includes a logical expression having a plurality of resource identification information, and the mediation device includes each of the name spaces corresponding to each name space. The name resolution request is transferred to each entry point of the name resolution mechanism, the set operation processing is executed for the address sent from each name resolution mechanism, and the address obtained as a result of the operation processing is returned to the user terminal. Name resolution system characterized by that. 12. The name resolution system according to claim 11 , wherein resource identification information included in a name resolution request transmitted from the user terminal to an intermediary device includes only name identification information for specifying a target resource, And means for extracting the namespace identification information to which the name belongs from the name included in the received resource identification information, and the name resolution is performed on the entry points of a plurality of corresponding name resolution mechanisms based on the obtained namespace identification information. A name resolution system characterized by forwarding each request.

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