Method for managing logical connections in a network of distributed stations, as well as a network station
The invention relates to the technical field of domestic networks. A domestic network based on the present UpnP-Standard allows AV connections to be set up between two network subscriber stations. Network connections such as these are set up and managed under the control of a network station which is in the form of a control point. In this case, the UpnP-Standard allows the network station which is the form of a control point to log off the network after setting up an AV connection, and thus to be inactive while the AV connection that has been set up is in existence. This results in the problem that an AV connection which has been set up unnecessarily remains in existence even after the desired AV data stream has been transmitted, so that further connection requests for such stations must be answered with a rejection. The invention solves this problem in that it provides additional monitoring means in the network subscriber stations which determine whether the connection has remained unused for a specific time. If yes, a signaling request is sent to all the network subscriber stations. If the connection partner station does not then respond, the connection which has been set up can likewise be added autonomously by the requesting station.
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The invention relates to the technical field of domestic networks.
BACKGROUND OF THE INVENTIONThe efforts to network evermore electronic devices to one another domestically or at home have already now progressed to a very major extent. A range of different standards for the networking of devices have now been worked out, some of which have different objectives. One of the systems envisages devices being networked on the basis of the so-called Internal Protocol IP. A first version of a Standard is already available for this system. This system has become known by the abbreviation UPnP, which stands for Universal Plug and Play. The corresponding standard is currently available, in Version 1.0. Further information related to the UPnP System and the associated Standard can be found on the official Internet site for the UPnP consortium at www.upnp.org. In the UPnP System, there are no restrictions on the device types. It is thus intended to be possible to network not only devices from the consumer electronics field such as TVs, DVD players, set-top boxes, video recorders, camcorders etc., but also domestic devices, such as washing machines, refrigerators, heating controllers, automatic coffee machines, and so on. Personal computers may form a specific category of devices, although these are also taken into account in the UPnP System and can also be integrated in the network.
However, the various layers of the OSI/ISO reference model for data communication are not specified in the UPnP system. This relates in particular to the bit transmission layer and the data link layer. The UPnP System therefore no longer contains any specification related to the transmission medium via which the data to be interchanged must be transmitted. Widely differing transmission standards are permissible here. These include, for example, the Ethernet Protocol, IEEE 1394 Protocol, wire-free transmission itself in accordance with IEEE 802.11x, Bluetooth or HIPERLAN/2.
Invention
In the course of UPnP Standardization, a specification for the transmission of AV data (audio/video-data) between network subscriber stations has also been worked out, and was completed in June 2002. The precise title of this specification is: UPnP AV Architecture: 0.83 dated Jun. 12, 2002. This specification defines three different types of devices for the transmission of AV data. Firstly a so-called media server, which is always allocated to that device which is chosen as the source of the AV data. The second device type is the media renderer, which is allocated to a device which is chosen as a data sink for the AV data. Thirdly, a control point type is also provided, as a dedicated type of device. A universal remote control for AV devices is generally considered to be an example of a control point device. However, alternatively, a personal computer in the network can also carry out this task, or else a TV with a remote control may likewise be suitable as a control point. The control point device communicates with two further UPnP devices, which may be used as a data source and data sink for a desired AV connection. The control point device initializes and configures both devices for the AV connection, so that the desired data stream can also be sent. Once an AV connection such as this has been set up, the control point device does not need to control the rest of the data transmission, and the UpnP AV specification does not contain any stipulations that the control point must be active all the time throughout the duration of the AV connection that has been set up. Instead of this, the control point device may also be disconnected from the network. The task of a control point device is thus typically to set up an AV connection between two network subscribers, to make any changes required to the settings of the two devices (typically including the volume setting, the brightness setting, the contrast setting, the tone setting, the sharpness setting and so on) and, once the desired AV data stream has been transmitted, to cap the connection once again, that is to say request both devices associated with the AV connection to delete the data that characterizes that connection.
If, however, as has already been mentioned above, the control point device is disconnected from the network once the AV connection has been set up, irrespective of whether this is a result of disconnection by the user or a result, of a malfunction, then it is possible for the situation to occur in which the two devices in the AV connection still remain connected to one another even after the AV data stream has been transmitted, and in the worst case even for as long as the devices remain switched on. This behavior conceals the risk that, if the control point device once again wishes to set up an AV connection for one of the previously connected devices at a later point in time, this new connection cannot be set up because one of the previously connected devices is still maintaining the old AV connection. The control point device could admittedly deal with this fault situation if it were previously to gather all the data about the connections that have been set up by all the network subscriber stations, but this would involve a high degree of complexity in terms of additional messages, which would be incurred whenever the control point device had previously been switched to be inactive.
The invention solves the problem in that a portion of the control point device functionality is implemented in media server and media renderer devices for an AV connection.
In a method for managing logical connections which have been set up in a network of distributed stations, provision is made for one station to monitor the connection which has been set up, to determine whether the station which is logically connected to it has sent a logging-off message and, if yes, for this station to autonomously internally end the setting up of the logical connection to the station that has logged of. Specifically, whenever a station in the UPnP System is switched off, it transmits the so-called ssdp:byebye message to all the other stations. If the station which is connected to the station that has logged off detects this logging-off message, then it is automatically clear that the connection can be ended. This is then carried out autonomously internally by the partner station.
However, a situation is possible in which a station is no longer able to send the logging-off message. For example, if the network plug for this station is pulled out, it is no longer possible to transmit this logging-off message. In this situation, it is advantageous for provision to be made for a station to monitor an AV connection to determine whether the logical connection has remained unused for a first specific time and if yes, to send a signaling request to the station in the network and, finally, to monitor all the signals from the network stations and, in the absence of signaling from the station to which it is logically connected, to automatically internally end the setting up of the logical connection. In consequence, a connection is thus correctly cleared even when a station which is logged off from the network is no longer able to send the logging-off message.
This measure can advantageously also be carried out in particular whenever a new connection request arrives at the station.
It is also advantageous if it is found after a signaling request that the other station in the logical connection that has been set up is still in the network but that the logical connection has remained unused for a second specific time, for the station which is carrying out the check to internally finally end the setting up of the existing logical connection, which has been inactive beyond the specific time limit (which may be several hours).
Corresponding advantageous measures for a network station are listed in claims 7-11.
DRAWINGSExemplary embodiments of the invention will be explained in more detail in the following description and are illustrated in the drawings, in which:
AV connections between two devices in a domestic network are set up in accordance with the AV specification for the UPnP Standard cited above. The UPnP AV specification in this case distinguishes between three different station types. Firstly a so-called media server. That station in an AV connection which is intended to be used as the data source is associated with the media server device type in accordance with the UPnP AV specification. The second type of device is a media renderer. This type is assigned to the device which has been chosen as the data sink for the AV connection. Another type of device is the control point. This device type is normally assigned to the device type on which the control values are displayed. This is thus normally a device which is equipped with a display. The TV in a domestic network is mentioned as one example. Other examples are a personal computer which is integrated in the domestic network, or a universal remote control with a display, which is likewise integrated in the domestic network by means of wire-free transmission.
A media renderer device receives the AV data stream that is transmitted from the media server and emits this either as picture information or as audio information. The media renderer device thus likewise contains an implementation of the AV transport protocol. In the same way, the media renderer device likewise contains an implementation of the connection manager module for communication with the control point device. Furthermore, a rendering control module is implemented in the media renderer device. This module is used, for example, to implement the command received via the connection manager to adjust replay characteristics, such as the volume, tone, picture sharpness, contrast, brightness, color and so on. A TV, a stereo amplifier and an MP3 player may be mentioned as example of devices to which the media renderer device type should be assigned in the domestic network.
A control point device coordinates the data transport between the media server and the media renderer. It is likewise used to implement the control commands from the operator and to pass them to the corresponding appliances in the AV connection. This relates in particular, as an example, to the play, stop, pause, fast forward and fast reverse commands. As mentioned, the control point device is likewise used to produce the user interface for the operator. The control point device is active in particular when setting up the logical connection between two network stations. It is likewise also used when the aim is to end the setting up of the AV connection after an AV connection has served its purpose, that is to say that the AV data stream has been transmitted as selected. However, UPnP AV specification does not stipulate as an essential feature that the control point device must remain active throughout the entire duration of the AV connection. The problems that are associated with this have already been explained in the introductory part of the application.
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Referring to
According to the invention, the set-top box 10 will then check whether the existing connection for the video recorder 20 is still valid. The way in which this is done will be explained in more detail later in conjunction with
In the UPnP-Standard, this is known by the abbreviation UUID for Universaly Unit Identifier. The program now checks in the next program step 55 whether the ssdp:alife(VCR) message has been received by the connected video recorder. If this is the case, then the program jumps to the program step 56, by means of which the program is ended. The connection is then therefore not ended. Otherwise, it is assumed that the connected device has been disconnected from the network without any logging-off message having been sent. The connection complete(STB) action is then called in the next program step 56, by means of which the connection entered in the memory for the set-top box 10 is deleted. The program is then ended in the program step 57.
The invention can be used in a worthwhile manner in particular for devices which are designed in accordance with the UPnP Standard. The invention provides advantages for UPnP-based domestic networks in particular when setting up AV connections which are frequently set up over lengthy time periods. AV connections such as these could, however, also for example be telephone, fax and Internet connections, which likewise also remain in existence over lengthy time periods.
Claims
1. A method for monitoring audio/video connections hereinafter called AV connections which have been set up in a network of distributed stations which are networked with one another via at least one of a wire-free and a wire bus connections wherein a station monitored to determine whether the station which is AV connected to it has sent a logging-off message and, if yes, in that this station autonomously ends the setting up of the AV connection with the station which is logged off.
2. The method as claimed in claim 1, wherein a station which is AV connected to another station sends a signaling request to the stations in the network in the situation where the AV connection has remained unused for a first specific time, and in that, in the situation where the signaling request remains unanswered by the station which is AV connected to the requesting station, the requesting station autonomously internally ends the setting up of the AV connection.
3. The method as claimed in claim 1, wherein when a new connection request arrives, a station from which an AV connection to another station has already been set up, sends a signaling request to the stations in the network and in that, in the situation where the signaling request remains unanswered by the station which is AV connected to the requesting station, the requesting station autonomously internally ends the setting up of the AV connection.
4. The method as claimed in claim 3, wherein, in the situation in which it is found that the other station on the AV connection which has been set up is still registered in the network, the logical connection has remained unused for a second specific time, the station which is carrying out the check autonomously internally ends the setting up of the existing AV connection.
5. The method as claimed in claim 1, wherein at least one of audio and video data is transmitted via the AV connection.
6. The method as claimed in claim 1, wherein the data transmissions in the network are carried out in accordance with the rules of the UPnP Standard.
7. A network station for a network of distributed stations which are networked with one another via wire-free or wire bus connections, having means for setting up an audio/video connection hereinafter called AV connection to another station, wherein the network station has monitoring means which it uses to monitor whether the station which is AV connected to it has sent a logging-off message, and furthermore having connection ending means for autonomously ending the AV connection which has been set up when the monitoring means finds that the logging-off message has been sent from the station which is AV connected to it.
8. The network station as claimed in claim 7, wherein the monitoring means are also designed to monitor whether the AV connection which has been set up has remained unused for a first specific time and, if yes, to send a signaling request to the stations in the network, and is also designed such that it autonomously internally ends the setting up of the existing AV connection if the signaling request remains unanswered by the station which is AV connected to the requesting station.
9. The network station as claimed in claim 7, wherein the monitoring means is designed to send a signaling request to the network stations when a new connection request for a further station has arrived and it has been found that the AV connection which has been set up has been unused for that time, with autonomous ending of the setting up of the existing AV connection when the signaling request remains unanswered by the station which is AV connected to the requesting station.
10. The network station as claimed in claim 9, wherein the monitoring means are also designed such that they end the setting up of the existing AV connection autonomously when it is found that the other station in the AV connection which has been set up is admittedly still registered in the network, but that the AV connection has remained unused for a second specific time.
11. The network station as claimed in claim 7, wherein the network station is designed for data transmissions in accordance with the UPnP Standard.
Type: Application
Filed: Oct 24, 2003
Publication Date: Dec 29, 2005
Applicant: Thomson Licensing S.A. (Boulogne-Billancourt)
Inventor: Ingo Hutter (Pattensen)
Application Number: 10/531,775