Method for exchanging information between devices in case of a change in network configuration and home network system therefore

Abstract

A method for exchanging information between appliances to notify a home server of a network configuration change and a home network system therefore is disclosed. In the present invention, when an electronic appliance is connected to a network, the appliance first transmits a particular message to a home server N (>1) times at interval of a first period and then transmits the particular message periodically at interval of a second period which is longer than the first period, thereby letting the homer server know which appliances are connected to the network in real-time.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for exchanging information between electronic appliances for notifying a managing appliance of network configuration changes and a home network system therefor.

b 2. Description of the Related Art

In a home network system as shown in FIG. 1 wherein a home server and a plurality of electronic appliances are connected through a network N, an arbitrary electronic appliance can be monitored and controlled through the network N.

In the home network system, a plurality of electronic appliances C1 through C4 such as washing machines or microwave ovens are connected to a home server appliance such as a refrigerator having built-in home server functionality. The manager of the home network system can control and monitor the plurality of electronic appliances connected to the home network in a centralized way by transmitting control commands to the plurality of electronic appliances and receiving information about the execution results of the control commands through a different appliance connected to the network such as a PC or a PDA.

When an electronic appliance is newly connected to the home network, the appliance is assigned a unique network address by the home server and becomes on-lined to the network. While an electronic appliance is on-lined to the network, the appliance can provide status information to the home server and respond to monitoring/control messages from the home server.

The home server maintains the appliances that are in on-line as connected appliances. The power to an on-lined appliance may be turned off abruptly by a user or the physical connection between the appliance and the network may get broken. In this case, the home server should be able to detect such conditions. Otherwise, the home server may provide wrong information to the user of the network and therefore the user may issue wrong control commands based on the wrong information.

SUMMARY OF THE INVENTION

In view of the shortcomings of the prior art, it is an object of the present invention to provide a home network system that is capable of monitoring the status of the devices connected to the network in real-time and thus allows reliable management of the devices and a method therefore.

In the present invention, an electronic device transmits a particular message to a managing device periodically to inform that the device is on-lined or transmits a message for connection close according to user's request.

In one embodiment of the present invention, when a device is connected to the network, the device transmits the particular message to the managing device N times at interval of a first period and then repeatedly at interval of a second period longer than the first period.

In one embodiment, if the managing device does not receive the particular message during the interval of the second period, the managing device transmits a message requesting a reply to the device and determines the status thereof based on the result.

In one embodiment, if it is determined that the device is off-lined, the managing device reduces management information for the device.

In one embodiment, if it is determined that the device is off-line, the managing device moves the information about the device from the information area for on-lined devices to the information area for off-lined devices after deleting information about the operation of the device.

In another embodiment of the present invention, the managing device regards a device that transmitted a connection close message as being off-lined and reduces management information for the device.

In another embodiment, if a command for monitoring or controlling the device regarded as off-lined is received, the command is not executed.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a typical home network system established in a house;

FIG. 2 illustrates exemplary components constituting a home network;

FIGS. 3 a and 3b illustrate home network systems in which the present invention may be advantageously embodied;

FIG. 4 illustrates a flow chart of the method for exchanging information between devices in accordance with a first embodiment of the present invention; and

FIG. 5 illustrates a flow chart of the method for exchanging information between devices in accordance with a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order that the invention may be fully understood, preferred embodiments thereof will now be described with reference to the accompanying drawings.

FIG. 2 illustrates a detailed schematic diagram of a managing device in a home network system. FIGS. 3a and 3b illustrate home network systems in which the present invention may be advantageously embodied.

A network manager 100 is a home server that controls signals exchanged between a plurality of electronic appliances connected to the network N and manages information for communication with other networks such as the Internet. In the preferred embodiments of the present invention, the network manager is built into a refrigerator that is powered all day long.

Also, the network manager 100 stores and manages network allocation information for network connection, operation status, and detailed setting for operation of each of the plurality of devices such as electronic appliances.

As shown in FIG. 2, the network manager 100 comprises a control unit 130, a database 140, and a communication module 150. The control unit 130 generates control commands for controlling the operation of each of devices 200_I connected to the network N. If the control unit 130 receives a message for connection close from a device or fails to detects a device on the network under the condition that it has not received an “alive” message during a predefined period of time from the device, the control unit 130 removes or modifies information about the device. The database 140 stores information about devices that are or were connected to the network N. The communication module 150 transmits and receives data through the network N.

The control unit 130 comprises a timer 131 for counting down a timeout value set by each of the devices 200_I, a control module 132, and a connection status monitoring module 133. If a timeout value that was set by one of the devices 200_I expires, the connection status monitoring module 133 monitors the connection status of the device. If a message indicative of connection close is received from a device or the connection status monitoring module 133 determines that a device is not found, the control module 132 regards the device as being off-lined and manages the device accordingly. The control module 132 regards devices that have transmitted the “alive” message on a regular basis as being on-line. Also, the control module 132 performs status monitoring or issues control signals according to user's request.

The type of the communication module 150 depends on the physical media used in constructing the network N. The communication module 150 is a power line modem in a power line network as shown in FIG. 3b and is a wireless modem in a wireless network. The communication module 150 is determined by what type of physical media is used.

The network manager 100 may further comprise an output unit 120 for outputting network status information and control results in response to control signals from the control unit 130. The output unit 120 can be built into a single panel with an input unit 110 for providing more convenient user interface.

Each of the devices 200_I comprises a control unit 230 and a communication module 250. The control unit 230 generates control signals for controlling components of the device in response to control commands received from the network manager 100 and transmits the “alive” message indicating that the device is on-lined to the network manager periodically at predefined intervals. Also, the control module 230 issues a message indicative of connection close when a special request is received from a user. The communication module 250 performs data communication through the network N.

Like the communication module 150 of the network manager 100, the type of the communication module 250 depends on the type of the media. The communication module 250 is a power line modem in case of a power line network and is a wireless modem in case of a wireless network.

When a device that has not been assigned a network address is connected to the network N, the device requests the network manager 100 to assign it a logical address. If a logical address is assigned by the network manager 100, the device generates a network address by combining the logical address with its own product code and sets the generated network address in the control unit 230 or the communication module 250. When assigning the logical address to the device, the network manager 100 adds the device to a table of on-lined devices and records network configuration information about the device. When operation status and information about the device is obtained afterwards, the network manager 100 records the obtained information in the information area corresponding to the device in the table of on-lined devices.

If a device was connected to the network N once and connected to the network again, the device already has a network address. In this case, the device transmits the “alive” message to the network manager 100 without performing the steps to get a logical address.

The “alive” message is transmitted to the network manager 100 periodically at short intervals at first and then at long intervals (AliveInt). For example, the “alive” message is transmitted twice at interval of 5 seconds and then transmitted at interval of 10 minutes. To notify the network manager 100 of the period of “alive” message, the device transmits the interval between “alive” messages, i.e., AliveInt, to the network manager 100.

Receiving the “alive” message through the communication module 150, the network manager 100 searches the database 140 for information about the device that transmitted the “alive” message. If the information about the device is found in the table of on-lined devices, the network manager 100 leaves it as it is. If the information is found in the table of off-lined devices, the network manager 100 moves the information to the table of on-lined devices. It is also possible to change the status of the device from ‘off-lined’ to ‘on-lined’ instead of moving the information. It is desirable, however, to manage information for on-lined devices and information for off-lined devices separately in the database 140 in that on-lined devices require more information than off-lined devices.

Receiving the period of the “alive” message (AliveInt) from a device, the control module 132 records a timeout value for the device in the information for the device. The timeout value is set to a value longer than the received period (e.g., 1.5×AliveInt or 2×AliveInt). Each time an “alive” message is received from a device, the control module 132 loads the timeout value associated with the device to the timer 131. The timer 131, which has only one clock source, counts down a plurality of timeout values at each clock tick to check if at least one timeout event occurs.

If the information on a device that transmitted the “alive” message is not found in the database 140, it means that the device has been connected to another network and moved to the network N without removing its network address. In this case, the control module 132 executes steps for clearing the network address and assigning a new address to the device.

If one of the timeout values set in the timer 131 of the network manager 100 reaches 0, it means that the “alive” message has not been received from the device which loaded the timeout value to the timer 131. In this case, the control module 132 requests the connection status monitoring module 133 to examine if the device exists on the network N.

Even when the device is connected to the network N, the “alive” message transmitted by the device may not reach the network manager 100 before the preset timeout expires because of excessive network load or instantaneous signal interference. This is why the examination is needed.

In summary, even though the “alive” message has not been received from a device during its preset timeout interval, the network manager 100 does not change information on the device immediately and examines if the device is connected to the network N through the connection status monitoring module 133.

To determine if the device exists on the network N, the connection status monitoring module 133 transmits a message requesting information (e.g., address) to the network N. In the case where the device is on-lined to the network N, the device receives the message and replies to the message by transmitting a message delivering its address. Receiving the message, the connection status monitoring module 133 notifies the control module 132 of the status so that the control module 132 keeps the information on the device unchanged.

If the device is off-line, e.g., connection is closed or power is turned off, the connection status monitoring module 133 cannot receive a reply to the message requesting address information.

As a result, the control module 132 of the network manager 100 moves the information on the device, which is currently included in the table of on-lined devices, to the table of off-lined devices in the database 140. In this case, information unnecessary in the table of off-lined devices (e.g., current function, status information, operation mode, etc) is removed. In the case where information should be minimized, all information except for the address of the off-lined device can be deleted when the information is moved to the table of off-lined devices.

Some devices are equipped with the functionality to request connection close. If the user of such a device requests connection close, the device transmits a message for connection close to the network manager 100. Receiving the message for connection close through the network N, the network manager 100 handles the information about the device that transmitted the message in much the same way as the information about the device that is not detected by the connection status monitoring module 133.

Because the network manager 100 monitors the status and configuration of the network N in real-time as described before, the network manager 100 can reply to user's requests or commands reliably.

If the network manager 100 has the output unit 120, the network manager 100 can display which devices are currently on-lined to the network N so that the user can easily monitor the network status. If the user issues a command or a request to an off-lined device through the network manager 100, the network manager 100 does not perform the command or request based on the database 140 thereof. The network manager 100 may inform the user of the status of the off-lined device.

A user issues control commands or requests through a device having user-friendly interface such as a PC, a notebook computer, or a PDA. Such a device is called a master device. Application programs for monitoring and controlling devices connected to the network are executed on the master device. Though the master device performs similar functions as the home server, the master device cannot assign logical addresses to devices connected to the network and does not support communication with other networks.

Because the master device should know the status and configuration of the network N in real-time to manage user's requests properly, the master device should have information table for devices that are currently connected or were connected to the network.

When the network manager 100 updates the database 140 thereof after detecting a change in the network configuration, the network manager 100 notifies the master device of the change so that the network manager 100 and the master device can synchronize databases. Likewise, if the master device detects a change in the network configuration first, the master device needs to notify the network manager 100 of the change. It also holds when there are more than one network manger on the network.

In a home network based on the wireless network as shown in FIG. 3a or based on the power line network as shown in FIG. 3b, if a home server 101 has not received the “alive” message from a device during its preset period of time, the home server 101 examines if the device is still in on-line to the network. If the home server 101 fails to receive a response from the device, the home server 101 moves information about the device from the table of on-lined devices to the table of off-lined devices and deletes unnecessary information.

FIG. 4 illustrates a flow chart of the method for exchanging information between devices in case of a configuration change in a home network in accordance with a first embodiment of the present invention.

An electronic appliance that is newly connected to the network is assigned a network address by the network manager if necessary and transmits the “alive” message and its own period of the “alive” message to the network manager to inform the network manager that the appliance is on line (S1). The appliance transmits the “alive” message N times (e.g., twice) at short intervals at first and then at long intervals. Receiving the “alive” message, the network manager records information about the appliance in the table of on-lined devices, if the appliance is assigned a new network address. If the appliance already has a network address, the network manager removes information about the appliance from the table of off-lined devices and records necessary information in the table of on-lined devices.

If the “alive” message has not been received during a time interval longer than the predefined period (e.g., 1.5˜2 times as long as the period) (S2), the network manager examines if the device exists on the network (S3).

If the device is not found on the network (S4), the network manager moves the information about the device from the table of on-lined devices to the table of off-lined devices (S5), in which case only the information irrelevant to the operation mode is moved and unnecessary information is deleted. If the device is found (S4), the network manager maintains the information about the device unchanged. Afterwards, the network manager waits for the “alive” message (S7).

FIG. 4 illustrates a flow chart of the method for exchanging information between devices in case of a configuration change in a home network in accordance with a second embodiment of the present invention. In this embodiment, an electronic appliance notifies the network manager of its status change from on-lined to off-lined.

If requested by the user, the appliance transmits a message for connection close to the network manager (S11). Receiving the message, the network manager deletes dynamic information about the appliance and moves only static information about the appliance to the table of off-lined devices (S12). In this case, even though the appliance is physically connected to the network, the appliance is considered off-lined (S13). Afterwards, the user removes the appliance from the network.

The home network system and the method therefore is capable of monitoring the status of appliances connected to a network in real-time, thereby minimizing errors in managing electronic appliances existing on the network and allowing reliable management of the network system.

While the invention has been disclosed with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that all such modifications and variations fall within the spirit and scope of the invention.

Claims

1. A method for exchanging information between devices in case of a change in network configuration, comprising the steps of: (a) transmitting a message of a first type to a managing device N times at interval of a first period when connected to a network, N being greater than 1; and (b) transmitting the message of the first type periodically to the managing device at interval of a second period after transmitting the message N times, the second period being longer than the first period.

2. The method set forth in claim 1, wherein N=2.

3. The method set forth in claim 1, further comprising the step of transmitting information about the second period to the managing device.

4. The method set forth in claim 1, further comprising the step of obtaining a network address by requesting network address assignment to the managing device before executing the step (a).

5. The method set forth in claim 1, wherein if the managing device fails to receive a message of the first type from a device within the second period, the managing device transmits a message of a second type to the device.

6. The method set forth in claim 5, wherein if there is no acknowledgement to the message of the second type, the managing device considers the device off-lined and reduces information about the device.

7. The method set forth in claim 6, wherein when reducing the information about the device, the managing device deletes information related to the operation of the device.

8. The method set forth in claim 6, wherein the reduced information still contains network address information about the device.

9. The method set forth in claim 6, wherein if a command for monitoring or controlling the device considered off-lined is received, the managing device provides information indicating that the device is off-lined, without executing the received command.

10. The method set forth in claim 1, wherein the first period is 5 seconds and the second period is 10 minutes.

11. A method, performed by a managing device, for managing information about devices connected to a network, comprising the steps of: (a) receiving a connection closing message from a device; and (b) considering the device off-lined and reducing information about the device.

12. The method set forth in claim 11, wherein when reducing the information about the device, the managing device deletes information related to the operation of the device.

13. The method set forth in claim 11, wherein the reduced information still contains network address information about the device.

14. The method set forth in claim 11, wherein the device transmits the connection closing message to the managing device according to user's request.

15. A network system through which a plurality of devices are connected, comprising: a managing device for managing information about the plurality of devices connected to a network; and a device for transmitting a message of a first type periodically to the managing device at interval of a second period after transmitting the message of the first type N (N>1) times at interval of a first period, the second period being longer than the first period.

16. The network system set forth in claim 15, wherein N=2.

17. The network system set forth in claim 15, wherein the device obtains a network address by requesting network address assignment to the managing device before transmitting the message of the first type.

18. The network system set forth in claim 15, wherein the device provide information about the second period to the managing device and the managing device sets a time limit based on the received second period and if a message of the first type is not received during the time limit, the managing device executes steps for detecting the device.

19. The network system set forth in claim 18, wherein the steps for detecting the device include transmitting a message requesting an acknowledgement and waiting for the acknowledgement.

20. The network system set forth in claim 18, wherein if the device is not detected, the managing device considers the device off-lined and reduces information about the device.

21. The network system set forth in claim 20, wherein when reducing the information about the device, the managing device deletes information related to the operation of the device.

22. The network system set forth in claim 20, wherein the reduced information still contains network address information about the device.

23. The network system set forth in claim 20, wherein if a command for monitoring or controlling the device considered off-lined is received, the managing device provides information indicating that the device is off-lined, without executing the received command.

24. The network system set forth in claim 15, wherein the first period is 5 seconds and the second period is 10 minutes.

25. A network system through which a plurality of devices are connected, comprising: a managing device for managing information about the plurality of devices connected to a network; and a device for transmitting a connection closing message to the managing device if there is a connection release request, wherein if a connection closing message is received, the managing device reduces information about the device which transmitted the message.

26. The network system set forth in claim 25, wherein when reducing the information about the device, the managing device deletes information related to the operation of the device.

27. The network system set forth in claim 25, wherein the reduced information still contains network address information about the device.

28. The network system set forth in claim 25, wherein the connection release request is a command entered by a user.

29. An apparatus for managing a device connected through a network, comprising: a communication module for transmitting and receiving data through the network; a database for storing management information including the network address information about the device; a timer for measuring time and detecting timeout of set time limit; and a control unit for reloading the timer with a time limit specified for the device each time a particular message is received from the device through the communication module, and reducing management information for the device as the result of considering the device off-lined if the time limit specified for the device expires.

30. The apparatus set forth in claim 29, wherein when reducing the information about the device, the control unit deletes information related to the operation of the device.

31. The apparatus set forth in claim 29, wherein the reduced information still contains network address information about the device.