MXPA06005815A - Method for monitoring the state of a device in a network and device for carrying out said monitoring - Google Patents

Abstract

The invention relates to a method for monitoring the state of a device in a communications network consisting at least of two devices, isochronous communications channels which transmit synchronised data packets by means of a signal emitted by the network in uniform time intervals. The inventive method consists in emitting data packets by a monitorable device through a specified isochronous channel in response to a signal regularly emitted by the network for the first monitorable device, monitoring the emission of the data packets by said synchronous channel for the second device and carrying out a specified task consecutively to the absence of the data packets on the isochronous channel between two emissions of synchronisation signals. A device for carrying out said method is also disclosed.

Description

METHOD FOR MONITORING THE STATUS OF A DEVICE IN A NETWORK AND DEVICE FOR MONITORING The invention relates to a method for monitoring the state of a device connected to a home network and to a detection device for monitoring via a network of another device.

A digital communication network comprises devices linked together through a communication bus (bus), for example the IEEE 1394 collector, using cables or waves. The communication network comprises, for example, the following devices: a terminal that allows users to project audiovisual broadcasts, input parameters to control the network and check the status of the network, a digital television receiver (a decoder, for example) capable of receiving audiovisual broadcasts and service information that originates from a transmission network, a device for storing audiovisual broadcasts, a modem, etc. The list of devices is not exhaustive, similarly there may be several of some devices within the communication network, for example, a camera in each room of the children.

The 1394 network allows the devices to communicate according to three different modes: the synchronous mode, where the data packets are broadcast regularly at the end of certain periods of time, the asynchronous mode, in which each message is isolated from the others and can be issued at any time, the isochronous mode, in which the data packets are issued regularly in a given time bracket. These various communication modes are used for the transfer of specific data. The commands are transmitted generally in asynchronous mode, the data transmitted in synchronous mode, and the internal data stream for the network, in isochronous mode. In this last case, we find monitoring data emitted by a camera arranged in a room of the children, projecting a television this data. Contrary to the audiovisual data received from a transmission network and subject to very precise and regular synchronizations, this monitoring only needs to receive an image from time to time, at times that may vary.

The monitoring of the proper operation of the network device is usually done through a device inherent in the device. We find for example the "Watchdog" devices, which activate an error message when, at the end of the chronometer, the central unit that is being monitored has not performed a certain action. This device must obviously be more reliable than the central unit that is loaded with the monitoring. Each device that is monitored must have its own device; the present invention makes it possible, among other advantages, to limit the number of monitoring devices, while being able to monitor a significant number of devices.

The document US 6 430 629 Bl-SMYERS, published on August 6, 2002, describes a 1394 network, and the possibility of monitoring the temperature of the rooms by virtue of modules that communicate with the help of this network. The invention relates more precisely to the "monitoring" of the state of a device of a network. A screen indicates the status of the device such as a VCR or an STB, and the temperature of the room. Claim 1 indicates that the signaling network periodically receives information indicating the status of the devices.

Document EP 1 185 034 - SONY, teaches error detection in a transmission circuit of a network, for example 1394. A network device is configured to detect connection errors in an isochronous channel, error detection it is done inter alia by the scrutiny of the signals "IEEE 1394 signal SI". Other detections can be made by analyzing the regularity of the emission of the data packets, thus defining a priority level in the error and a specific action, for example the display on a screen of the error detection. This document teaches a device that exercises monitoring in all communications of the network, and not specifically in a device that you want to monitor.

The present invention consists of a method for monitoring the state of a device within a communication network comprising at least two devices, the network comprising isochronous communication channels that transmit data packets synchronized by a signal emitted by the network, which is it emits at regular intervals of time; characterized in that it comprises the following steps.

At the level of a first device that it is desired to monitor: - emission through the device that is monitoring the data packets in a specified isochronous channel, in response to the signal broadcast regularly by the network; at the level of the second device: - monitoring of the emissions of the data packets issued in the isochronous channel; - execution of a specified task, consistent with the absence of data packets in the isochronous channel between at least two synchronization signal emissions.

In this way, the monitoring of the state of a device completely uses the resources of the network using the synchronization signals of the isochronous emissions and making use of them to detect the premature termination of the data emissions in those channels.

According to a first refinement, the method comprises a step of issuing a monitoring request that contains an identifier of the isochronous channel that transmits the packets and a descriptor of the task. In this way, the device to be monitored informs the device loaded with monitoring what to do in case of malfunction.

According to another refinement, the monitoring request specifies a predetermined number of synchronization signals. In this way, the monitor device waits for the detection of the predetermined number of signals to activate the execution of the specified task.

According to another refinement, the method comprises a step of transmitting through the second device a driving signal that follows the description of the monitoring request. Therefore, the device that requests to be monitored knows that this monitoring is undertaken by a device in the network.

According to another refinement, the specific task comprises the deployment of an alert message comprising an identifier of the first device. Therefore users of the network can be warned of a malfunction.

According to another refinement, the specified task comprises a step of analyzing the reason for the stoppage of the data packet emissions, and a step of actions to execute to resume the emission of the data packets. In this way, network devices can automatically eliminate the causes of some malfunctions.

The subject of the invention is also a network device loaded with the monitoring of the state of at least one other device of the network, comprising a means of communication with a network that perceives the synchronization signals that allow the emission of the isochronous data. and isochronous data packets issued on a specified isochronous channel; characterized in that it further comprises the means for executing a specified task consistent with the absence of data packets in the isochronous channel between at least two synchronization signal emissions, the absence of packets being indicative of the state of the device being monitored.

Other features and advantages of the present invention will emerge from the description of the example representations that follow, taken as non-limiting examples, with reference to the attached Figures, where: Figure 1 represents a block diagram of a known local network; Figure 2 represents the block diagram of a network according to an example representation of the invention; Figure 3 represents the sending of a request to monitor a first device towards an Isochronous Communications Control Unit; Figure 4 represents the processing of a monitoring request by an Isochronous Communications Control Unit; Figure 5 depicts a flow chart showing the operation of an Isochronous Communications Control Unit that controls two isochronous channels; Figure 6 represents the diagram of an Isochronous Communications Control Unit according to an exemplary representation of the invention; Figure 7 represents a flow diagram showing the main steps of the method according to an example representation of the invention.

With the help of Figure 1, first of all we will describe a local digital communication network according to the current state of the art. This network comprises, for example, the following devices: device 1: a camera; - device 2: a computer equipped with a DVD player, an interface with the telephone network (typically a modem) and an integrated decoder; - device 3: an STB decoder equipped with a tuner and DEMUX demultiplexer which makes it possible to receive the emissions of a transmission network, and a memory (typically a hard disk) which makes it possible to store the programs and data received from the network of transmission; - device 4: a digital video recorder.

Other devices (not shown) are possible within the scope of the invention: a projection screen, an analog video recorder, temperature sensors for heating regulation and fire detection, motion detectors for detecting the presence of individuals with a view to the alarm. All these devices are linked together through a digital collector using the IEEE 1394 standard. According to this standard, the devices communicate together in an asynchronous or isochronous manner. An isochronous communication makes it possible to transmit an uninterrupted data stream between, for example, a camera and a screen that projects the video signals of the camera, a temperature sensor that transmits the information to the heating plant. An isochronous channel has the representation of regularly transmitting the data from an emitter to a receiver in a parenthesis of time defined by a certain bandwidth. The aim of the network node called the Clock Master (or "Master of the Cycle") is to guarantee a regular timed recording of the isochronous packets broadcast on the channels. For this purpose, the Master node issues a cycle start signal every 125 milliseconds to all other nodes in the network. This signal serves as a synchronization to issue the data packets. The network also comprises a device equipped with a software resource called Isochronous Resource Director (IRM). The IRM module handles a memory in which the identifiers of the various isochronous channels as well as the bandwidths are recorded. For this purpose, the IRM is equipped with bandwidth allocation and channel assignment records. The IRM allows the management of the isochronous channels and the bandwidth available in the network. The control of the isochronous channels is in a favorable way, returned to the Clock Master.

According to a preferable example representation of the invention, the network also comprises a Ischronic Channels Control Unit (ICCU) for short, and for the rest of the document). The ICCU is equipped with the function of the network, which ensures the monitoring of the various isochronous channels activated in the local network. An ICCU is any of the devices connected to the network: the Clock Master node, the device that has the IRM, or another node in the network, which has and is equipped with a monitor module according to an example representation preferable of the invention. According to a variant, an ICCU is a specific device loaded with the monitoring of isochronous channels, it is implemented in the network as shown in Figure 2.

Now we will detail the behavior of the monitoring through an ICCU. A device in the network can execute an important task, therefore its execution is monitored by an ICCU. A task is in a favorite way a program executed by a Central Unit, this can also be sequential logic integrated in a specialized circuit, for example an ASIC. In the normal behavior of the task to be monitored, care will be taken to implement the specific emission of the data in a determined isochronous channel. The important thing is not in the content of the data but in the periodicity of the emissions. Therefore, it will be possible, advantageously, to send very short packets. The smallest isochronous packet issued in an IEEE 1494 network that has been made from an isochronous and a fraction header. This data is contained in 528 location units, which represent a duration of 10 microseconds. In the initiation step of the task to be monitored, the device will program the ICCU to monitor its operation, then the 1CCU will monitor the emissions in the isochronous channel.

As illustrated in Figure 3, a device (2) sends a monitoring request comprising its identifier, the identifier of an isochronous channel, the channel (19), for example, which verifies the correct operation of the device, and a Describer of the task to be performed if the data emitted in this channel disappear. The ICCU receives the request, records the parameters and begins monitoring by scrutinizing the data packets issued on the specified channel. If the network comprises several ICCUs, the first available ICCU sends a message of consideration of the monitoring with the characteristics in the network, registers the parameters in its memory, and immediately begins to monitor. The other ICCUs that perceive this management message do not involve themselves in this monitoring. The data must be issued every 125 microseconds. During an interruption of the emissions as illustrated in Figure 4, the ICCU searches in its memory for the parameters of the alert task it must perform. For example, this task is the emission of a "datol" data to a "dirl" address of the network. This address can be the device (2), specifically if this device is equipped with a multi-tasking system, the one that triggers the issuance of the isochronous packets can be interrupted, but not the one that handles the reception of the network data . In this way, the device (2) can be warned in advance from the outside about an internal malfunction. The address can also be another device in the network, a projection terminal for example, and then the data "datol" is a drop-down message. The projection terminal then displays the alert message for the user's attention.

The monitoring requests sent to an ICCU contain inter alia the following information: - identifier of the device that issues the monitoring request, - number of the isochronous channel: 1, 2, etc. (or the identifier of the data packets), - maximum duration between packets of the isochronous channel, or maximum number of emission of signals of start of cycle before the execution of the task of alert, - descriptor of the task of alert.

The descriptor of the alert task describes the various actions of the ICCU carried out during the detection of the disappearance of an isochronous channel. Here are several actions that can be in an alert task: - issuing an alert message: "Disappearance of channel 1", intended for all screens of the residence. The message is sent in an asynchronous manner to each projection device, - emission of a sound signal by the ICCU, - activation of a programmed succession of actions to fix the malfunction detected by the ICCU.

Alert tasks is stored and sent as it is in the network. If the device being monitored does not specify any alert task, the ICCU has a task by system consisting of displaying on a network screen all the parameters available to inform a user of the malfunction. The message displayed is, for example, "at 20:30, interruption of the emissions of the isochronous channel (2), originated from the device (1)". The user can then intervene in the device (1) and correctly re-establish the task.

A variant is that the device being monitored defines the alert action accurately and reports it to the ICCU. For example, a user programs the recording of an emission in the digital channel (21), this channel being provided by a decoder that receives the signals from a transmission network, the recording task executed in the recording device is monitored by an ICCU . At the time of reception of the broadcast, the recording device programs the decoder to receive the broadcast, and records the first data packets received through the network. Assume that the receiver stops emitting, then the recording task is interrupted. The ICCU detects at the end of the time outside an interruption of the recording task, the specific descriptor that must display a follow-up message on the screen of the room: "premature termination of the recording at 20:30", where 20:30 it is a variable updated by the ICCU. A refinement is that the descriptor received by the ICCU has several actions to take as a function of the analysis of the causes of the malfunction. In accordance with the previous example and with this refinement, the descriptor received by the ICCU prevents analyzing the presence of audiovisual data packets that originate from the channel (21) during the course of each determined duration. If the packet is not detected, the ICCU calls a second decoder and sends a request to receive the channel (21). If the request is accepted, the recording continues normally on the basis of the data emitted in the home network by the second decoder. If, on the other hand, no decoder is available, the ICCU displays on a screen a message indicating the premature termination of the recording due to the unavailability of a decoder. In this way, the ICCU can resolve certain malfunctions, as well as maintain a recording within the local network using the available resources in its entirety.

Figure 5 illustrates the chronology of two tasks monitored by an ICCU. A device (1) executing a task (1) sends a data packet in the isochronous channel (1) and a device (2) that executes a task (2) sends another data packet in the isochronous channel (T2). The ICCU, which monitors the two channels, synchronizes itself with the cycle start signals issued by the Clock Master. The ICCU detects the presence or absence of isochronous packets issued by each of the channels that are being monitored between two signals of cycle start. A second data packet is emitted in the channel (1), therefore the task executed by the device 81) operates correctly. On the other hand, no data packet is output on channel 82) before the emission of a third cycle start signal. Therefore, when this third cycle start signal is detected, the ICCU deduces from this that the channel (2) is no longer supplied and that the task (2) executed by the device (2) is no longer operating correctly. This causes the corresponding alert task for the malfunction of the task (2) in the device (2). "The example described above does not exclude from the present invention the case in which both tasks (1) and (2) are executed in the same device.

A refinement is that the ICCU waits for a predetermined number of signals to start cycle before activating the action described in the descriptor. advantageously, this predetermined number is set by the device that wishes to be monitored and is transmitted in the descriptor of the alert task. This refinement makes it possible to economize on the bandwidth by allowing the device being monitored to send an isochronous data packet only after a certain number of start cycle signals. For this purpose, the Central Unit contained in the ICCU has an available counter and the data count for each isochronous channel is placed in a new column of the array recorded in the RAM.

An example representation of an ICCU is described in Figure 6. If an ICCU is physically a standard device equipped with a specific program, or a device dedicated to monitoring, its general structure is the same. An ICCU has a central unit (6.1), connected to a memory (6.2) ROM in which at least the monitoring program is registered, a memory (6.3) RAM for the storage of the programming data, a circuit (6.4) of logic interface for communication with the IEEE 1394 collector and an interface circuit (6.5) to interconnect with the 1394 network.

The interface circuit (6.4) supports the handling of isochronous channels. The circuit constantly monitors the data of the local network and, with the help of digital filters, extracts certain packets according to their identifiers. In this way, a receiver can permanently receive the data broadcast in an isochronous channel, without the need to search for them. The interface circuit (6.4) is, for example, a TSB43AB22 circuit, manufactured by the Texas Instruments company. This circuit generates a hardware interruption in the reception of a data packet that acts on the behavior of the program executed by the central unit (6.1). This circuit can discriminate the channel by virtue of two interrupt mask registers that specify the reference of that channel, thereby making it possible to filter the channel or the isochronous channels to be monitored. This circuit is compatible with the IEEE 1394 standard. The memory (6.3) RAM records the data corresponding to the various monitoring of the isochronous channels used. This data (channel identifier, device identifier, alert task descriptor, cycle start signal counter, etc.) are arranged in an array.

With the help of the flow chart of Figure 7, we will now detail the sequence of steps according to an exemplary implementation of the invention. In step (7.1) a device in the network causes a task that needs to be monitored. Then it issues a request to an ICCU of the network specifying the isochronous monitoring channel and the action to be taken if the emissions are stopped (step (7.2)). In step (7.3), the device of the network being monitored begins to regularly issue the data packets in the isochronous channel. The ICCU analyzes each packet in the network and verifies that each device being monitored actually outputs at least one data packet between two (or a certain number of) cycle start signals (step (7.4)). Let's assume that a device stops its emissions (step (7.5)). During the reception of the next cycle start, the ICCU notices the stop of the emissions in the specified isochronous channel and causes the execution of the scheduled task (step (7.6)).

A variant consists of equipping the ICCU with an interpreter. In this way, it is possible to program the alert action in a language that is interpreted by the ICCU (for example, QUICK BASIC) and that makes it possible to define with precision the actions to be performed.

The example representations of the invention that were presented above have been chosen because of their specific character. However, it would not be possible to catalog in a comprehensive manner all the representations that this invention covers. In particular, any step or any means described may be replaced by a step or an equivalent means without departing from the competence of the present invention.

Claims (12)

REVINDICAT IONS

1. Method for monitoring the state of a device within a communication network comprising at least two devices, the network comprising isochronous communication channels that transmit data packets synchronized by a signal emitted by the network, which is issued at regular intervals of time; characterized in that it comprises the following steps: at the level of a first device that it is desired to monitor: - emission by the device being monitored of data packets in a specified isochronous channel, in response to the signal issued regularly by the network; at the level of a second device: - monitoring of the packets of data transmitted in the isochronous channel; - execution of a specified task, consistent with the absence of data packets in the isochronous channel between at least two emissions of the synchronization signals.

2. Handling method according to claim 1, characterized in that it comprises, at the level of the first device, a step of issuing a monitoring request containing an identifier of the isochronous channel that transmits the data packets and a task descriptor. , executing the second device the task thus specified by the first device.

3. Handling method according to claim 2, characterized in that the monitoring request specifies a predetermined number of synchronization signals, the second device executing the specified task when no data packet has been detected in the isochronous channel following the detection of the specified number of synchronization signals.

4. Operation method according to claim 2 or 3, characterized in that it comprises a transmission step, by the second device, of a control signal immediately after the reception of the monitoring request.

5. Method of handling according to any of the preceding claims, characterized in that the specified task comprises the deployment of an alert message that includes an identifier of the first device.

6. Handling method according to any of the preceding claims, characterized in that the specified task comprises a step of analyzing the reason for stopping the emissions of the data packets, and a step of executing actions in order to resume the issuance of data packets.

7. A network device loaded with the monitoring of the state of at least one other device in the network, comprising a means of communication with a network that perceives the synchronization signals that allow the emission of isochronous data and of isochronous data packets issued in a specified isochronous channel, characterized in that it further comprises a means for executing a specified task consistent with the absence of data packets in the isochronous channel between at least two synchronization signal emissions, with the absence of data packets indicative of the state of the device that is being monitored. Network device according to claim 7, characterized in that it comprises a means for receiving a monitoring request containing the identifier of the isochronous channel that transmits the data packets and a descriptor of the specified task, being recorded in a memory the device identifier of the channel and the descriptor of the task. Network device according to claim 8, characterized in that the received monitoring request specifies a predetermined number of synchronization signals and in that it comprises a counter of the synchronization signals, executing the specified task when no detection has been detected. data packet in the isochronous channel following the detection of the specified number of synchronization signals. 10. Network device according to any of claims 7 to 9, characterized in that it comprises a means for displaying an alert message activated by the absence of data packets in the isochronous channel between at least two signal emissions of synchronization 11. Network device according to any of claims 8 to 10, under the dependency of claim 8, characterized in that it comprises a means for emitting a management signal immediately after receiving a monitoring request. 12. Network device according to claim 11, characterized in that it comprises a means to prevent the handling of a monitoring request, which is activated when the receiving means with the network perceives a signal to handle the request through another network device.