KR100736037B1 - SYSTEM AND METHOD FOR EXPANDING UPnP FUNTION - Google Patents

Abstract

The present invention relates to a system and method for extending the UPnP function, the system for expanding the UPnP function according to the present invention, the control point for transmitting a control message while being outside the NAT network; A controlled device existing within the NAT network and controlled by the control point; And a forwarding device connected to the controlled device to mediate a connection between the control point and the controlled device.

The method of extending the UPnP function may include: transmitting, by a controlled device connected to a network, an advertisement message; Forwarding the advertisement message to a control point by the forwarding device receiving the advertisement message; And registering, by the forwarded control point, a service of the controlled device according to the advertisement message.

UPnP, NAT traversal, control point, controlled device, discovery process, control process

Description

Expansion system and method of JPNP function {SYSTEM AND METHOD FOR EXPANDING UPnP FUNTION}

1A to 1D are diagrams illustrating operations of each step in a conventional home network device-to-device control process.

2 is a diagram showing the configuration of a conventional NAT traversal system.

3A is a diagram illustrating a concept of an extension system of UPnP function according to an embodiment of the present invention.

3B is a diagram illustrating a configuration of an extension system of UPnP function according to an embodiment of the present invention.

4 is a diagram illustrating a discovery process of a method for extending a UPnP function according to an embodiment of the present invention.

5 is a diagram illustrating a control process of a method of extending a UPnP function according to an embodiment of the present invention.

Description of the main parts of the drawing

100: forwarding device 200: control point

300: controlled device

The present invention relates to an extension system and method of the UPnP function, and more particularly, to an extension system and method of the UPnP function to enable the UPnP function to be applied even under a NAT network or a general Internet environment.

In general, the home network is composed of a private network based on the Internet Protocol (hereinafter referred to as IP), and includes all types of personal computers (PCs), intelligent products, and wireless devices used in the home. Control various devices in a single network through a common virtual computing environment called middleware.

Middleware is a device that enables communication between devices by connecting various digital devices in a peer-to-peer manner, such as HAVI (Home AV Interoperability), UPnP (Universal Plug and Play), and Jini (Java). Intelligent Network Infrastructure (HFW) and Home Wide Web (HWW) have been proposed to date.

In computing environment, which is built by UPnP middleware, each device is assigned an address assigned by server or selected by Auto IP according to Dynamic Host Configuration Protocol (hereinafter referred to as DHCP). It is assigned and performs communication between each device and search / inquiry on the network.

The UPnP network is a home network device (Controlled Device), which is connected to and controlled by an IP-based home network, and a Control Point, which is a device for controlling these controlled devices. It is composed.

1A to 1D are flowcharts illustrating operations of each step in a device-to-device control process of a conventional UPnP network.

Currently, the inter-device control process in the UPnP network is composed of a discovery-advertisement process, a description process, a control process, and an eventing process.

FIG. 1A illustrates a discovery-advertisement process, which is an advertisement process in which a new controlled device is connected to a home network to notify other devices on the home network, A new control point can be described by dividing it into a discovery process of searching for controlled devices connected to the home network and operating on the home network.

First, a controlled device newly connected to a network in an advertisement process is assigned a predetermined IP address through DHCP or Auto IP technology, which is a search protocol, according to an addressing process. And multicasting an advertisement message informing the control points of the mobile station to inform the service provided through the device.

In addition, the control point that can control the operation of the controlled device receives an advertisement message provided by multicast and registers it as a control target.

On the contrary, a control point newly connected between networks in a discovery process is assigned a predetermined IP address through DHCP or Auto IP technology, which is a discovery protocol, according to an addressing process, thereby controlling the controlled point operating on the network. Multicast search messages according to SSDP technology, a search protocol to identify devices.

In addition, the controlled device that receives the search message transmitted from the control point unicasts a response message to the control point in response to the received search message.

FIG. 1B illustrates a description process, in which the control point uses an IP address of a controlled device obtained in a discovery-advertisment process in order to control a controlled device. ) The process of checking the function of a newly added device in detail by checking a file or a device description XML file.

That is, a control point that wants to control a controlled device requests a service description XML file or a device description XML file from the controlled device, and provides a description XML file (UPnP description for device, UPnP description for service) requested from the controlled device. Receive and parse.

FIG. 1C illustrates a control process. In this process, when a control point wants to provide a specific service through a controlled device, a control message for requesting a predetermined service using SOAP according to the UPnP device architecture is shown. ) Is transmitted to the controlled device, and a response message (result, variable value) is received.

The control message and the response message are transmitted / received using the IP address of the controlled device obtained during addressing and discovery-advertisement, and are expressed in XML using SOAP.

FIG. 1D illustrates an event process, which refers to a process of confirming an information change state of a controlled device providing a predetermined service by a control command transmitted from a control point. That is, when the control point transmits a subscription request message to the controlled device to confirm the information change state of the controlled device, the controlled device sends a GENA (Generic Event Notification Architecture) to notify the changed information. Send an event message in XML format. The control point receives the event message transmitted from the controlled device and processes it as a description update item for the controlled device.

2 is a diagram showing the configuration of a conventional NAT traversal system.

An Internet gateway usually provides Network Address Translation (NAT) as a means of connecting multiple hosts to the Internet sharing one public IP address.

Network address translation (NAT) is used to allow multiple PCs or devices to share a single, globally routable IPv4 address on a private network (using private address ranges such as 10.0.xx, 192.168.xx, and 172.xxx). Internet Engineering Task Force (IETF) standard. The main reason for the widespread use of NAT is because there are very few IPv4 addresses remaining. NAT is used in Internet gateway devices, especially for high-speed network sharing through DSL or cable modems.

When NAT is used in a private network due to lack of IPv4 addresses, all hosts outside the private network communicate through a single shared IP address, which can cause network layer problems, and NAT is not the same as a firewall or proxy server. It also serves to protect the network.

However, such a NAT technology does not support the connection of many kinds of network applications, there was a problem that can not detect the existence of the local NAT device 20, in order to solve the network application in the NAT environment to the local NAT device ( The technology developed to detect the existence of 20) is NAT Traversal technology. This technique has been defined in the UPnP forum, and port mapping can be performed using a NAT device 10 that provides support for an Internet gateway.

The NAT traversal of FIG. 2 detects that the network aware application is behind the NAT device 10, obtains an external IP address, and configures port mapping to use packets from external ports of the NAT network in the application. It is a function to forward to an internal port. All of this is automatic, so you don't have to configure your own port mappings or use any other mechanism.

It can be seen that the configuration of FIG. 2 includes a NAT device 10 and a local device 20. The NAT device 10 supports NAT traversal by providing a specification of an Internet Gateway Device (IGD) defined by the Internet Gateway Working Committee of the UPnP Forum. The local device 20 is a device in a NAT network that provides a service by requesting port mapping to the NAT device 10 supporting UPnP.

In order for the local device 20 to perform port mapping on the NAT device 10, the following process is performed.

First, the local device 20 checks the existence of NAT and obtains an external IP address of the NAT. And, if it is mapped, the static port mapping information for a specific external port is obtained. If the external port is not already assigned, the static port mapping is added and the static port mapping is deleted. In FIG. 2, the local device 20 has internal IPs of 10.0.0.2, 10.0.0.3, and 10.0.0.4. When passing through the NAT device 10, the local device 20 transmits data to the server 30 through an external IP of 157.55.1.10. You can see that you are sending.

However, this technique has a problem that it is difficult to apply to multiple NAT networks. In addition, the function of UPnP is not considered to be extended to the general Internet network, and in particular, there is a problem that a P2P network between devices over a NAT network is very difficult.

The present invention has been made to solve the above problems, beyond the limitations on the UPnP as described above, the extension system of the UPnP function to facilitate the P2P communication of the period even in the general Internet network and NAT network environment And methods.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

An extension system of the UPnP function according to the present invention for achieving the above object is a control point that exists outside the network and transmits a control message; A controlled device existing within the network and controlled by the control point; And a forwarding device that is connected to the controlled device within the network and mediates a connection between the control point and the controlled device.

In addition, the method for extending the UPnP function according to the present invention for achieving the above object, the control device connected to the network transmitting the advertising message; Forwarding, by the forwarding device receiving the advertisement message, the advertisement message to a control point existing outside the network; And registering, by the forwarded control point, a service of the controlled device according to the advertisement message.

In addition, the method for extending the UPnP function according to the present invention for achieving the above object comprises a first step of connecting the forwarding device to a control point existing outside the network; A second step of the forwarding device receiving an action request from the control point; And forwarding the received control message to a controlled device connected to the network.
In addition, the forwarding device according to the present invention for achieving the above object, the connection portion for connecting to a control point existing outside the network; A receiver which receives an action request from the control point; And a forwarding unit configured to forward the received control message to a controlled device connected to the network.

Specific details of other embodiments are included in the detailed description and the drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3A is a diagram illustrating a concept of an extension system of UPnP function according to an embodiment of the present invention, and FIG. 3B is a diagram illustrating a configuration of an extension system of UPnP function according to an embodiment of the present invention.

FIG. 3a conceptually illustrates that a UPnP device is connected to an external control point and an internet network through an IP router and a DSL modem in a home, and FIG. 3b schematically illustrates this. FIG. 3B includes a forwarding device 100, a controlled device 300, and a control point 200. The forwarding device 100 and the controlled device 300 form a UPnP device. Is assumed to be inside a NAT network.

The control point 200 serves to transmit a message to the controlled device 300 while being outside the NAT network, and the controlled device 300 is present inside the NAT network and being controlled by the control point 200. Message is received by delivery of the forwarding device 100.

In addition, the forwarding device 100 serves to mediate a connection between the control point 200 outside the UPnP network and the controlled device 300 while being connected to the controlled device 300. That is, when there is a control point 200 outside the NAT network, the NAT network becomes a failure to control the controlled devices therein from the outside, and the forwarding device 100 penetrates the NAT network using the HTTP protocol to control the control. It is to mediate message transmission and reception between the point 200 and the controlled device 300.

Specifically, the forwarding device 100 forwards an advertisement message of the controlled device 300 to the control point 200 in a search process, and in the control process, a control message from the control point 200. An action request is received and forwarded to the controlled device 300. In addition, the forwarding device 100 forwards the response message received from the controlled device 300 to the control point 200. The control point 200 is connected to the control point 200 at predetermined intervals according to a predetermined period, and the control point 200 determines whether a control message is held. Forward to controlled device 300. That is, the forwarding device 100 uses a polling method that periodically connects to the control point 200 and determines the existence of a held message.

4 is a diagram illustrating a discovery process of a method for expanding a UPnP function according to an embodiment of the present invention.

The discovery process of UPnP works only in the local network and not in the NAT network environment or the general Internet environment, for the following reasons. As shown in FIG. 1A, the controlled device and the control point multicast the advertisement message and the discovery message, respectively, in the discovery process. To reduce congestion in the network, the TTL value of the IP packet is set to 4 by default. In other words, you can't go through more than four routers. In addition, the controlled device 300 or the control point 200 must use IGMP to pass through the multi-router, which means that the router must forward the multicast message. In reality, however, it is not possible to assume that routers are configured to forward multicast messages in all Internet environments where UPnP devices are used. Therefore, when the control point is external in the discovery process of UPnP, the forwarding device 100 as in the embodiment of the present invention is required in order to connect the controlled device to the external Internet network. ), It is possible to extend the search function.

4, the controlled device 300 connected to the network first transmits an advertisement message to the external control point 200 (S402). However, in the present invention, the forwarding device 100 receives an advertisement message, and the forwarding device 100 receiving the advertisement message controls the advertisement message. Forward to the point 200 (S404). The forwarded control point 200 registers the service of the controlled device 300 according to the advertisement message (S406). Subsequent processes follow the normal UPnP process. That is, the discovery process according to the present invention is assumed that the forwarding device 100 performs the advertisement and discovery processes of the control point 200 and the controlled device 300 because of the firewall role of the NAT network. Can be.

That is, in the discovery process under the Internet network or NAT network, the advertisement message and the discovery message are in a state in which the control point 200 and the controlled device 300 cannot be transmitted to each other. This is caused by using a multicast protocol. In order to solve this problem, the forwarding apparatus 100 directly accesses the control point 200 using TCP / IP and sends an advertisement message of the controlled apparatus 300. Is solved by sending

On the other hand, Figure 5 is a view showing a control process of the expansion method of the UPnP function according to an embodiment of the present invention.

Unlike the discovery process, the control process can be performed in general internet network, but it can't be applied in NAT network.

In the control process, the control point 200 first sends an action request message to the controlled device 300. However, if the controlled device 300 is present in the NAT environment in this process, the NAT network performs a function of a firewall and thus cannot receive an action request message. Therefore, the control process of UPnP in NAT environment requires a forwarding device like the present invention.

The control process in the present invention will be described with reference to FIG. 5, wherein the forwarding device 100 connects to the control point 200 (S502), and the control point 200 transmits a control message (action request). When the forwarding device 100 receives this (S504). Then, the received control message is forwarded to the controlled device 300 (S506), and according to the control message, the controlled device 300 transmits a response message after performing an operation and forwards the forwarding message. The device 100 receives this (S508). The received response message is forwarded to the control point 200 (S510). In addition, the control point 200 is connected to the control point 200 to determine whether there is a held control message at a predetermined period (polling method). In this case, the step of disconnecting is further added.

In conclusion, it can be seen that the control process is extended in a NAT environment. Under the NAT environment, the controlled device 300 cannot receive an action request message from the control point 200. In order to receive the action request message, the forwarding device 100 connects to the control point 200 using TCP / IP, and the control point 200 connects the controlled device through the connection. 300 to send a control request (action request message). The subsequent process is performed by the forwarding apparatus 100 by retransmitting messages from both sides.

An embodiment of the present invention is to extend the discovery function and the control function by using the forwarding device 100 to perform a discovery and control process in the Internet and NAT environment. can see.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains have various permutations, modifications, and modifications without departing from the spirit or essential features of the present invention. It is to be understood that modifications may be made and other embodiments may be embodied. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the present invention, it is possible to extend the function of UPnP to a general Internet network, and also to support the function of UPnP in a NAT environment which is a current general home network environment. This allows UPnP devices to provide more scalable and diverse services.

Effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Claims (11)

A control point present outside the network and transmitting a control message; A controlled device existing within the network and controlled by the control point; And And a forwarding device connected to the controlled device within the network to mediate a connection between the control point and the controlled device. The method of claim 1, wherein the forwarding device, UPnP function expansion system for forwarding the advertisement message of the controlled device to the control point. The method of claim 1, wherein the forwarding device, The UPnP function expansion system of receiving a control message (action request) from the control point and forwarding to the controlled device. The method of claim 1, wherein the forwarding device, UPnP function expansion system for forwarding the response message received from the controlled device to the control point. The method of claim 1, wherein the forwarding device, UPnP function expansion system for connecting to the control point according to a predetermined period to receive a command message held in the control point and to forward to the controlled device. Transmitting, by the controlled device connected to the network, an advertisement message; Forwarding, by the forwarding device receiving the advertisement message, the advertisement message to a control point existing outside the network; And And registering, by the forwarded control point, the service of the controlled device according to the advertisement message. A first step of connecting the forwarding device to a control point existing outside the network; A second step of the forwarding device receiving an action request from the control point; And a third step of forwarding the received control message to a controlled device connected to the network. The method of claim 7, wherein A fourth step of receiving a response message from the controlled device that has performed an operation according to the control message; And And forwarding the received response message to the control point. The method of claim 8, Determining whether there is a control message held at the control point; And And determining that there is a reserved control message from the second step, and releasing the connection if there is no reserved control message. A connection portion for connecting to a control point existing outside the network; A receiver which receives an action request from the control point; And a forwarding unit configured to forward the received control message to a controlled device connected to the network. The method of claim 10, And the receiving unit receives a response message from the controlled device that has performed an operation according to the control message, and the forwarding unit forwards the received response message to the control point.

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