KR20100044434A - Universal service broker for interoperability between sub-networks - Google Patents

Abstract

PURPOSE: A broker for ubiquitous sub network connection is provided to enable users to easily search a heterogeneous sub network service using a web service as an intermediate medium in environments in which heterogeneous sub network environments and various computing environments are integrated. CONSTITUTION: Basic information of a US(Universal Service) broker is offered to a device or a user terminal. An adaptor collects meta data information of devices. The collected information is delivered to a registration agent. The registration agent stores the metadata information. An inquiry agent notifies location information and metadata of devices through which services are possible to the user terminal. A routing proxy connects a sub network service.

Description

Universal service broker for interoperability between sub-networks}

The present invention relates to a broker for interworking a ubiquitous subnetwork using a heterogeneous subnetwork as a universal network and a web service as an intermediate medium in a heterogeneous subnetwork environment and various computing environments.

Ubiquitous Web Services (Ubiquitous Web Services) can be defined as a future web services technology that can be used by connecting various application services in any terminal or network environment. Ubiquitous web services need to actively search for and use services that are constantly changing devices and services, and support search methods in an ad hoc environment. Accordingly, research is being conducted in various fields such as transaction, security, QoS, semantic and web service combination.

Recent technologies to support ubiquitous web services include the development of WS-Eventing in BEA, Microsoft, and Sun Microsystems, the development of WS-Base Notification in OASIS, and the development of WS-Brokered Notification in IBM, Sonic. Microsoft is actively developing and developing standards for mobile web services, Web services on devices, and invisible web services platforms for ubiquitous environments. We are promoting web service technology development strategy by taking advantage of. In Korea, we are planning to actively use web services as Soft Infraware for convergence of IT839 services, and technologies such as semantic search and match making are being conducted in universities and research institutes. . However, domestic and international studies of ubiquitous web services are in their infancy and have not sufficiently reflected various requirements.

As described above, problems in the fluidity of the location, state, and information of devices and services based on different protocols and platforms can be solved through the service discovery middleware. Hereinafter, the service discovery middleware is referred to as a sub-network. Representative subnetworks include Sun Microsystems' Jini (Java Intelligent Network Infrastructure), Microsoft's Universal Plug and Play (UPnP), and Home Audio / Video Interoperability (HAVi). There is a Device Profile for Web Services (DPWS). However, not only does one subnetwork not support each other's interoperability, but also it cannot reflect all the heterogeneous characteristics of various physical layers. While various subnetworks exist, there is still insufficient method to overcome the heterogeneity of scattered subnetworks.

This paper examines the existing researches for interoperability of heterogeneous subnetworks.

Table 1 shows the research for integration between subnetworks and the characteristics of research and subnetwork for integration between devices.

The most representative subnetworks, Jini and UPnP, are used by OSGi (Open Service Gateway Initiative) and DomoNet (Domotics Network) because they best reflect heterogeneous characteristics. OSGi is a service gateway that provides an open standard for delivering services to a local network or device and operating the delivered services. DomoNet transforms the services of a subnetwork into web services to ensure interoperability of heterogeneous subnetworks. Jini, which is used in researches for integrating such subnetworks, has a disadvantage of requiring a Java virtual machine based on Java, but includes many features such as plug and play and security. UPnP, on the other hand, is independent of the programming language but does not support broadband network environments and is vulnerable to security. Web services to provide interoperability in heterogeneous environments support many features, but do not support plug and play, making dynamic service discovery impossible. Also, it cannot be applied properly in the ubiquitous environment because it cannot provide web services from the device perspective. As part of solving the problems of web services, DPWS is supported, and it is being spotlighted as the next generation technology of UPnP that reflects the characteristics of ubiquitous environment by supporting web services from a device perspective.

An extension of OSGi, OSGi provides a service framework for the integration of heterogeneous subnetworks. This is a combination of the advantages of OSGi's services gateway and distributed middleware.

FIG. 1 is a block diagram illustrating an extended structure of OSGi, and illustrates an extended structure of OSGi for device interworking through control services. In this architecture, the OSGi device manager, which consists of an OSGi registry, a device locator, and a device selector, connects to the subnetwork.

In order to use the features of the OSGi gateway, a control service is created for each subnetwork to provide an interface for connecting to the OSGi gateway. It also handles events and converts and delivers messages that the OSGi framework cannot handle.

The characteristics of such a gateway of OSGi are as follows.

▶ Application Service: Provides a service applicable to all applications.

Portable applications: The framework contains code and configuration files that are portable to the application itself. In other words, the framework manages the components of applications and libraries.

Application management: The framework runs the process of installing, starting, stopping, changing, or deleting any application or program.

Interface services: Modularize applications for interoperability between applications for code reuse.

▶ Increased safety: Detects errors and system defects and solves them.

DomoNet, on the other hand, is taking a SOA-based approach to ensure interoperability of heterogeneous subnetworks by converting the services of the subnetwork into web services. To this end, there is a TM (TechManager) that is responsible for converting a service to a web service. As shown in FIG. 2, the TM is efficiently used because it is located in each subnetwork and performs a process of transforming all services depending on the subnetwork. TM, which is in charge of connecting DomoNet network and subnetwork, converts services provided by subnetwork into web service according to the status of subnetwork to make available in DomoNet environment.

In the present invention, a broker for interworking a ubiquitous subnetwork that allows a user to easily discover and use a heterogeneous subnetwork service through WSUN using a web service as an intermediate medium in an environment in which the heterogeneous subnetwork environment and various computing environments are converged. The purpose is to provide.

In order to achieve the above object, the present invention provides a listener, an adapter, a registration agent, a universal service registry, A universal service broker including a query agent and a routing proxy.

In the present invention, (A) the listener provides the device or user terminal with basic information of the US broker including address and host information so that the WSUN device or user terminal appearing in the network can communicate with the US broker. ; (B) the adapter collects and transmits metadata information of devices existing in the network to the registration agent and converts the service of the subnetwork into a virtual web service; (C) the registration agent stores metadata information of devices received from the adapter in the universal service registry and the UDDI registry; (D) The query agent first searches a UDDI registry for a service search query from a user terminal, and secondly retrieves metadata and location information of serviceable devices from the universal service registry. Notify the user terminal; (E) the routing proxy connects a subnetwork service which is a real service of the virtual web service when a connection request from a user terminal to the virtual web service is received; Function and role.

In the present invention, the adapter is a universal adapter that plays a role of relay between the subnetwork and the US broker. The implemented adapter is a Jini adapter for the Jini- based subnetwork device and a DPWS adapter for the DPWS-based subnetwork device. It is preferred to be configured.

At this time, the universal adapter, (A) a message transmission function for mediating the necessary information transfer between the sub-network and the US broker; (B) a subnetwork service search function for searching for a service of a subnetwork and collecting necessary meta information; (C) a virtual web service generation function for converting a service of a subnetwork into a virtual web service type; (D) event and notification functions for changing the status information of the service for the appearance and exit of the subnetwork and the devices of the subnetwork, and the termination of the use of the service; (E) interworking with web services registered in the UDDI registry to users in the subnetwork; It is preferable to include.

The universal service registry in the present invention, (A) device / service registry for storing the specification information of the device and service of each sub-network and the specification information of the WSUN device; And (B) a context registry for storing dynamic information of devices and services of each subnetwork.

According to the present invention, interworking between subnetworks is enabled using a web service in an environment in which heterogeneous subnetwork environments and various computing environments are converged using heterogeneous subnetworks as universal networks.

In addition, according to the present invention, since it is possible to discover a variety of services reflecting location and status information of devices and services on heterogeneous subnetworks, the search and use of services required by the user can be efficiently provided.

The present invention proposes an appropriate response and strategic vision for changes in the ubiquitous environment, and can be expected to provide competitive system development and service reuse and web service application services through ubiquitous web services.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. However, these drawings are only examples for easily describing the content and scope of the technical idea of the present invention, and thus the technical scope of the present invention is not limited or changed. In addition, it will be apparent to those skilled in the art that various modifications and changes can be made within the scope of the present invention based on these examples.

6 is a conceptual diagram illustrating a US broker structure according to the present invention. Here, the US broker is divided into a storage layer (Register Layer), a management layer (Management Layer), a transfer layer (Binding Layer), a binding step (Binding Layer), the storage phase is a universal service registry, the management phase is registered with a query agent An agent is a listener and an adapter in the transport phase and a routing proxy in the binding phase. Their functions are as follows.

(A) Listener: Provides basic information of US broker to communicate with US broker when WSUN device and user terminal appear in WSUN. For example, it can be the information of US broker's address, host, etc., and make environment for registration or user terminal of WSUN device to search and find service.

(B) Adapter : A universal adapter that acts as a relay between a subnetwork and a US broker. The implemented adapter consists of a Jini adapter for Jini-based subnetwork devices and a DPWS adapter for DPWS-based subnetwork devices. It is preferable.

The universal adapter plays a role of relay between the subnetwork and the US broker. It is a bridge for communication between heterogeneous subnetworks and US brokers. It converts services of subnetworks into virtual web services to support universal services. 7 is a block diagram illustrating an example of the functionality of a universal adapter. The universal adapter has the following functions.

① Message Transfer : It is responsible for transmitting the information necessary for the subnetwork and US broker. This is mediated through the universal adapter because of the heterogeneous communication protocols between the US broker and the subnetwork.

Sub-network Services Discovery : Converts a subnetwork service into a virtual web service and retrieves information to be stored in the universal service registry. The retrieved information is sent to the registration agent after the virtual web service is created and stored in the universal service registry.

③ Virtual Web Services Creation : Since the user terminal searches for and uses a service without recognizing the existence of the subnetwork, the service of the subnetwork is converted into a web service type. The converted service is exposed to the user terminal as a virtual web service externally. In this way, the user terminal appears to use Web services, but the services of the subnetwork are actually provided through the universal adapter.

④ Events and Notifications : Supports Plug and Play by reflecting the appearance and exit of subnetwork and devices of subnetwork. In addition, when the user terminal terminates the use of the service, the service state information is changed to enable the service.

⑤ Interoperability with Web Services : Provides a list of services registered in the UDDI registry to users in the subnetwork and connects them to be used when a user requests the use of web services.

(C) Publish Agent: Registers metadata information necessary for WSUN's environment in Universal Service Registry and UDDI Registry. When metadata information existing in a WSUN device or subnetwork is collected by the universal adapter, the metadata is stored in the device / service registry and the context registry of the universal service registry.

(D) Query Agent: Processes the service search query of the user terminal. When the query agent receives the service search query of the user terminal, the query agent retrieves metadata of the device / service registry of the universal service registry and location information of the service of the context registry and informs the user terminal.

(E) Routing Proxy: When a user terminal requests a US broker to connect a desired service from a service search result, the routing proxy is responsible for connecting the subnetwork service, which is the actual service of the virtual web service.

(F) In the present invention, the universal service registry (US Registry) is preferably composed of a device / service registry and the context registry.

① Device / Service Registry : Stores metadata used in WSUN environment, that is, specification information of devices and services of each subnetwork and specification information of WSUN devices. In this way, when the US broker receives a service search query from the user terminal, the US broker can not only search for devices and services existing in the subnetwork, but also provide service status information as well as service status information. The device / service registry stores only the common, static, and essential elements of the device and service information of the subnetwork. In order to extract only these elements, it is preferable to limit the range to Jini UPnP and DPWS to extract device and service information as shown in Table 2 below.

If the universal service registry does not exist, the mediator method should be used to search all subnetworks or WSUN devices when a search query is made. This has the advantage that dynamic service search is possible because it does not need the module to manage the services provided by each subnetwork and WSUN device, but it cannot include the status information of the service and the search time is increased.

On the other hand, there is a data warehouse method that stores and manages all metadata information of a subnetwork or WSUN device in a registry. Although it can solve the increase of service retrieval time caused by the intermediary method, the burden of registering, deleting or modifying all metadata information in the registry is increased. Thus, the device / service registry of the universal service registry may take a hybrid method of extracting and managing only common, static, and essential elements of device and service specification information of each subnetwork.

Context Registry : As the location of devices changes frequently in the ubiquitous environment, the context registry is used as context information to store the location information of the device and search for the service that matches the location information of the user terminal. For example, searching for available printers in a meeting place. This will later be extended to ontology searches such as user terminal profiles.

On the other hand, the US broker according to the present invention follows the web service protocol stack suitable for the US broker because it converts the service of the subnetwork into a virtual web service and provides it to the user terminal.

5 is a protocol stack of a US broker, and is composed of USDP, WS-Eventing, WS-Addressing, Simple Object Access Protocol (SOAP), Web Services Description Language (WSDL), and XML Schema. ① WSDL contains specification information of transport protocol for connection and interface of service. ② XML Schema defines data format of sending / receiving message for using service. ③ SOAP is a transport service of message format defined in WSDL. It enables to integrate various web service protocols for. Currently, SOAP is used, but it is extended to simple SOAP gSOAP [18] by modifying SOAP to fit the lightweight environment of ubiquitous. ④ WS-Addressing is closely related to SOAP. All messages sent and received contain address information in the header of SOAP. This allows messages to be sent by any transport protocol, including HTTP, SMTP, TCP and UDP. ⑤ USDP is a protocol for discovering services. It provides search in plug-and-play and networked ad-hoc environments. Universal service retrieval through the US broker is enabled with the handling of the entry and exit of WSUN devices. ⑥ WS-Eventing is a protocol for handling events generated from liquidity such as service location and status information. For example, even if the user terminal has stopped using the service, the service status information is changed, so it is delivered to the US broker through WS-Eventing.

A US broker with the above structure and function will do the following.

(A) Service search: Dynamic service search is performed by storing the device and service meta information of the subnetwork in the registry of US broker. To this end, it is responsible for searching for devices and services existing in each subnetwork such as JINI, UPnP, and DPWS.

(B) Service registration and management: After retrieving device and service information of each subnetwork, it registers in device / service registry and context registry of universal service registry and manages according to availability of service.

(C) Service connection: It is in charge of the connection to use the desired service after searching for the service of the user terminal. Since the user terminal recognizes the use of virtual web services, it supports the use of the services of the subnetwork to be used.

(D) Creating a virtual web service: The service of a subnetwork is provided to a user terminal as a virtual web service through a US broker. The user terminal can recognize the web service only as a web service so that the user terminal can be used without being restricted by the environment of the user terminal and the subnetwork.

(E) Event handling of services. Ensure that only services available for dynamic service discovery and use are provided. When the location of the device or the use of the service of the user terminal is terminated, the state of the service changes, and thus the information is reflected.

A block diagram illustrating the structure of Web Services on Universal Networks (WSUN) in which a US broker according to the present invention is used is illustrated in FIG. 3. The system configuration for the universal network based web service includes a US broker, a universal service registry, and a universal adapter.

Through this configuration, WSUN provides the user terminal with a universal service that converts the services of each subnetwork into virtual web services. Since the services of each sub-network are provided through the virtual web service, the user terminal can search and use any service as the web service.

The US broker acts as a middleware that supports interoperability of heterogeneous and scattered subnetworks as a major component of WSUN. The US broker can be located between the service user terminal and the service provider to discover and use the services of the subnetwork and the services provided by the WSUN device.

The US broker performs the following functions in the process of discovering, registering, and managing services.

(A) User terminal appearance: Must support communication with US broker to enable user terminal to search or use service in WSUN environment. That is, the US broker must provide the user terminal with a way to search for the service. In this process, the user terminal does not have to establish a separate environment to use the US broker. 4 shows a process of discovering a US broker and communicating with the US broker by the appearance of a user terminal (Client).

(B) The appearance and exit of a subnetwork: If a subnetwork such as JINI or UPnP appears or exits the WSUN, device and service information should be reflected in the US broker. Dynamic service retrieval is possible by storing device and service meta information of sub-network in Universal Service Registry of US broker. However, a subnetwork supporting P2P such as DPWS does not appear or leave the WSUN on a subnetwork basis.

(C) When devices in a subnetwork appear and exit: the location of the devices in the subnetwork is flexible. Since the state of services provided by the device is dependent on the appearance and exit of the device, it should be able to detect the situation and suggest an appropriate solution. That is, the US broker should be able to provide only the services available to the user terminal.

(E) WSUN device appearance and exit: WSUN device is a device that supports the WSUN environment, the US broker must be able to support the appearance and exit of the WSUN device.

(F) Service search and connection of the user terminal: When the user terminal requests a service search query to the US broker, it should inform the search result about it and connect the user terminal to use the desired service among the searched services.

1 is a block diagram showing an extended structure of OSGi.

2 is a block diagram illustrating the concept of a DomoNet system.

Figure 3 is a block diagram showing the structure of Web Services on Universal Networks (WSUN) in which the US broker according to the present invention is used.

4 is a flowchart illustrating a process in which a user terminal appears to discover a US broker and communicate with the US broker.

5 is a block diagram showing a protocol stack of a US broker.

6 is a conceptual diagram showing a US broker structure according to the present invention.

7 is a block diagram illustrating a functional structure of a universal adapter that can be applied to a US broker according to the present invention.

Claims (4)

To support the discovery and use of universal services for users of devices in Web Services on Universal Networks (WSUN) configured with heterogeneous subnetworks, Universal Service Broker, including listeners, adapters, registration agents, universal service registries, query agents, and routing proxies, (A) the listener provides basic information of the US broker including address and host information to the device or user terminal so that a WSUN device or user terminal appearing in the network can communicate with the US broker; (B) the adapter collects and transmits metadata information of devices present in the network to the registration agent, converts the service of the subnetwork into a virtual web service, and provides a web service to a user in the subnetwork; (C) the registration agent stores metadata information of devices received from the adapter in the universal service registry and the UDDI registry; (D) the query agent retrieves and notifies the user terminal of the metadata and location information about the serviceable devices from the UDDI registry and the universal service registry for the service search query from the user terminal; (E) the routing proxy connects a subnetwork service which is a real service of the virtual web service when a connection request from a user terminal to the virtual web service is received; Universal service broker, characterized in that. The method of claim 1, The adapter, A universal adapter serving as a relay between a subnetwork and a US broker, the implemented adapter being a Jini adapter for Jini-based subnetwork devices and a DPWS adapter for DPWS-based subnetwork devices. The method of claim 2, The universal adapter, (A) a message transmission function that mediates the necessary information transfer between the subnetwork and the US broker; (B) a subnetwork service search function for searching for a service of a subnetwork and collecting necessary meta information; (C) a virtual web service generation function for converting a service of a subnetwork into a virtual web service type; (D) event and notification functions for changing the status information of the service for the appearance and exit of the subnetwork and the devices of the subnetwork, and the termination of the use of the service; (E) web service interworking function to provide web services to users in a subnetwork; Universal service broker comprising a. The method according to claim 1 or 2, The universal service registry, (A) a device / service registry that stores specification information of devices and services of each subnetwork and specification information of WSUN devices; And (B) a context registry for storing dynamic information of devices and services of each subnetwork; Universal service broker comprising a.

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