CN1155890C - Connection management method for managing connections between devices in a network system - Google Patents

Abstract

A connection management method for managing connections between devices in a network system. In the system, one or more devices that transmit data using a predetermined data transmission format are connected with one or more devices that receive data through a predetermined digital interface. The method includes The following steps: (a) A control device controls a plurality of devices, and notifies the control device of state changes involving established connections that occur in the plurality of devices, and the state changes of established connections are notified to the control device. The step of notifying the controlling device is performed in response to a connection management command sent to the controlled device, wherein if the changed connection counter bit field in the transmitting information device indicates that the number of devices used to receive information from the transmitting device occurs change, the connection of the device intended to receive the information is disconnected or connected, and, if multiple devices for receiving information from the transmitting device change and a dedicated connection is established, all but the one or Devices other than multiple receiving devices stop receiving messages.

Description

Connection management method for managing connections between devices in a network system

technical field

The invention relates to the field of data transmission control, in particular to a connection management method and a corresponding command structure, wherein the user can be notified of the change of the connection management state between devices connected by a digital interface.

Background technique

Home or industrial devices can be connected to each other by a bus in a predetermined digital interface format, such as the Institute of Electrical and Electronics Engineers (IEEE) 1394 standard, to transmit or receive real-time data with each other. For example, when digital televisions (DTVs), digital camcorders, set-top boxes (STBs), and similar devices are interconnected via IEEE 1394 to form a network, real-time data, such as video and audio information, is transmitted between these devices .

1 is a schematic view showing a conventional network system connected via IEEE 1394, in which real-time data is output from a virtual output plug of one device and input to an input plug of another device. In this case, the connection is established conceptually rather than physically. A source device (here STB 100) having an output plug 101 for transmitting information includes an output plug control register (oPCR) 111 for controlling the flow of information output through the output plug, while a source device for receiving information having an input The sink device of the plug 201 (here, the DTV 200 ) includes an input plug control register (iPCR) 211 for controlling the flow of information input to the input plug 201. The control device with the controller 300 can be one of STB 100 and DTV 200 or another third-party device, and the control device is used to establish a connection so as to control the control value of the oPCR 111 and iPCR 211 to transmit data or Disconnect.

Therefore, real-time data is transmitted from the output plug 101 to the input plug 201 . In this case, corresponding to each plug, relevant control information is written in oPCR 111 and iPCR 211, and the controller reads the value written in oPCR 111 and iPCR 211 or writes a control value there , to control real-time data flow.

The control values written into oPCR 111 and iPCR 211 will be described below in conjunction with accompanying drawings 2 and 3. The format of the 32-bit oPCR 111 represented in FIG. 2 is described as follows. The numbers indicate the number of bits allocated. "Online" indicates whether the corresponding output plug is online (value "1") or offline (value "0"). The "broadcast connection counter" indicates the presence (value "1") or absence (value "0") of a broadcast-out (broadcast-out) connection in the output plug, while the "point-to-point connection counter" indicates the presence (value "0") of a point-to-point ( p2p) the number of connections. "Channel number" indicates the channel number available for the output plug to transmit the isochronous data stream when the output plug is activated. "Data rate" denotes the transfer speed (or bit rate) required by the output plug to transfer the isochronous packets of the isochronous data stream when the output plug is activated. "Overhead ID" indicates the required bandwidth other than the bandwidth required to transmit the payload of the isochronous packet. "Payload" indicates the maximum length of isochronous data output from the output plug when the output plug is activated.

The format of the 32-bit iPCR211 shown in FIG. 3 is described as follows. The numbers indicate the number of bits allocated. "Online" indicates whether the corresponding input plug is online (value "1") or offline (value "0"). The "broadcast connection counter" indicates the presence (value "1") or absence (value "0") of a broadcast-in connection in the input plug, while the "point-to-point connection counter" indicates the presence (value "0") of a p2p connection in the input plug Number of. "Channel number" indicates the channel number available for the input plug to receive the isochronous data stream.

Therefore, if a control device with a controller is assigned a channel value for writing each channel value assigned in oPCR 111 and iPCR 211 in the channel numbers shown in Figures 2 and 3, and in oPCR 111 Write other control values (that is, online bit value, connection counter value, etc.) into iPCR 211, then the corresponding source device and sink device transmit or stop transmitting information according to these values.

As shown in Figure 2 and Figure 3, there are two types of connections used to transmit information: p2p connections and broadcast connections. In the case of a p2p connection, only one controlling device that establishes the connection can disconnect. Therefore, in the case where a third-party control device establishes a p2p connection, the source device and the sink device between which the connection is established must each transmit and receive information, even if not required.

In order to overcome the above problems, when any device no longer requires to receive or transmit data, a new one has been defined in the audio-video/control command transaction set (audio-video/control command transaction set: AV/C CTS) Control commands to propose an algorithm for informing the controlling device or other connected devices of this fact. Specifically, when any change occurs in a device that transmits or receives real-time data, a new control command is defined in AV/CCTS to represent the change. According to the AV/C CTS, information can be obtained on whether each input plug is required to receive any input and whether each output plug is required to output. In addition, when a signal output from the output plug changes, the information can also be known. However, when using the commands of the AV/C CTS, there is a problem that the variation of other factors used to control the flow of data is not available, other factors such as bandwidth and information about how many devices are connected to the connection involved Information.

Contents of the invention

In order to solve the above-mentioned problems, an object of the present invention is to provide a connection management method that indicates changes in various connection states with respect to data transfer streams during real-time data transfer, such as the status of data transfer and reception, data processing capabilities, and data availability. Bandwidth in which data transfer takes place between devices connected by a predetermined digital interface format.

Another object of the present invention is to provide a connection management method for generating a connection management command in response to changes in various connection states through which data transport streams are transmitted.

Still another object of the present invention is to provide a connection management command structure for indicating changes in various connection states in a data transmission stream when real-time information is transferred between devices connected by a predetermined digital interface format.

Therefore, in order to achieve the above objects of the present invention, a connection management method for managing connections between devices in a network system is provided, in which one or more devices that transmit data using a predetermined data transmission format and one or more devices that receive data The device is connected through a predetermined digital interface, the method includes the following steps: (a) a control device controls a plurality of devices, and notifies the control device of a state change that occurs in the plurality of devices and involves an established connection device, the step of notifying the controlling device of the state change of the established connection is performed in response to a connection management command sent to the controlled device, wherein, if the changed connection counter bit field in the transmitting information device indicates If the number of devices for receiving information from the transmitting device is changed, the connection of the device that wants to receive connection, all devices other than the one or more receiving devices originally associated with establishing the connection cease to receive information. .

In order to achieve another object of the present invention, a connection management method for managing connections between devices in a network system is provided, including the following steps: (a) between a device that transmits information in a predetermined data transmission format and a device that receives information Establishing a connection, the two are connected by a predetermined digital interface; (b) sending a connection management command for controlling the connection management state; and (c) when receiving a response to the connection management state change, controlling the connection according to the connection management command .

Description of drawings

By describing in detail preferred embodiments of the present invention in conjunction with the accompanying drawings, the above-mentioned purpose and advantages of the present invention will become more clear, wherein:

Fig. 1 is a schematic view representing a network system connected via a conventional IEEE 1394 bus;

FIG. 2 is a diagram representing the format of an output plug control register (oPCR) shown in FIG. 1;

FIG. 3 is a diagram representing the format of the input plug control register (iPCR) shown in FIG. 1;

FIG. 4 is a diagram representing a connection management command structure according to the present invention;

Fig. 5 is a flowchart of a connection management method according to an embodiment of the present invention.

Detailed ways

According to the present invention, when the output plug control register (oPCR) and the input plug register (iPCR) defined in the format of IEC 61883 (Digital Interface Specification for Electronic Audio/Video Apparatus, Part 1, December 1995, HD Digital VCR Conference) ) when the control value of ) changes, a connection management command structure is defined as shown in Figure 4, which is used to notify a control device or another device connected to this change, and it is the same as defined in the audio-video/control command Consistency of the command form in the transaction set (AV/C CTS), among which, IEC 61883 is the data transfer format for devices using the IEEE 1394 format.

In Figure 4, opcodes are defined for connection management, and one operand[0] is allocated one byte. The 1-byte field includes: the most significant bit (MSB), indicating the connection register type (iPCR/oPCR); followed by 1 bit that is reserved; and the remaining 6 bits, indicating the plug identification information about the plug number that establishes the connection. Adding other operands (operand[1] - operand[4]) to operand[0] allows the transfer of various information about connection management.

Specifically, it is possible by specifying only certain bit fields in the oPCR format shown in Figure 2 (online, broadcast connection counter, point-to-point connection, channel number, data rate, overhead ID, and payload) and only specifying Certain bit fields in the iPCR format (online, broadcast connection counter, point-to-point connection, channel number) are used to prevent the transmission of unnecessary responses. Therefore, when a control device requires to know the changes of some bit fields in the 32-bit oPCR or iPCR, the control device only needs to use the operand (operand[1]-operand[4]) to set the bit position of the corresponding bit field is "1" to transmit the set operand to the source device or the sink device using the notify command. For example, if only the in-line bit field is required, only the desired bits can be specified. In other words, if the bit position corresponding to the line is b0, transfer is done by setting only the bit position corresponding to b0 in the operand (eg, operand[1]) to "1" and setting the remaining bits Both are set to "0".

In addition to the factors contained in eg the connection management formats shown in Figs. 2 and 3, an operand [n] as to whether the connection is only for a dedicated purpose can be added to the connection management structure shown in Fig. 4 . Therefore, a device (control device) connected via IEEE 1394 performs transmission to another device (source device or sink device) by designating an output plug or an input plug with the connection management command shown in FIG. 4 . In this case, the connection management command can be defined as a new command of the notification command defined in AV/C CTS. There are several types of AV/C CTS commands, and the notify command is one of them. If the controller sends a notify command when it needs to know about a future change in state, the device (also called the target) that receives the notify command first passes the The controller responds by sending its own current state, and if the state changes later, the target responds by sending the changed state again to the controller.

In the present invention, if a connection management notification command as shown in FIG. 4 is transmitted, and a change occurs in any bit of the plug control register specified by the connection management notification command, the device receiving the notification command sends a message to the device that transmitted the notification command. Resend the change in response. A device receiving this response reads information about the corresponding plug control register of the other device, checks which bit field has changed, and takes appropriate action depending on the changed bit field.

Specifically, in the case where the device receiving the notify command is a source device with oPCR, if the on-line bit field in several bit fields changes from "1" to "0", it can be interpreted that the source device did not transmit the output Or it is not required to do so, so the controlling device disconnects the source device. Conversely, if the on-line bit field changes from "0" to "1", the source device requests to transmit an output, so the control device establishes a connection with the source device. For example, if a DTV does not output a signal at the end of a normal broadcast program, the control device disconnects the DTV.

In the case of a change in the value of the broadcast connection counter or the p2p connection counter, this indicates that the change in connection status is caused by overlaying other devices on an already established connection or disconnecting an already overlapped connection. When the value of the p2p connection counter is "1" because the source device with the control device has established a connection, if the value becomes "2", it can be considered that another device receives the information output from the source device. In this case, if a connection is established only for an exclusive purpose, the user can be notified that information accessed by him/her can also be accessed by others, thereby allowing the user to properly handle the situation.

If the payload value representing the output information bandwidth in the oPCR bit field changes, the control device can take appropriate measures based on the changed output information bandwidth of the source device and the bandwidth that the sink device can input. For example, if the bandwidth of the output information transmitted by the source device exceeds the bandwidth that the sink device can receive and process, the control device may disconnect the sink device, thereby preventing the sink device from receiving further information.

In the same way, in the case that the device receiving the notification command is a sink device with iPCR, if the on-line bit field changes from "0" to "1", it is considered that the sink device requires to receive an input, thereby controlling the device Establish a connection with the sink device. Conversely, the sink device can no longer be considered to require input, so that the control device can disconnect the sink device. For example, when a videocassette recorder (sink device) runs out of all recordable area of the tape and enters a blank signal area, the user is immediately notified of this situation in order to eject or replace the tape.

Fig. 5 is a flowchart of a connection management method according to an embodiment of the present invention, wherein the connection management method is executed by a control device including a controller. Referring to FIG. 5, according to the procedure defined in IEC 61883, a connection is established between the source device and the sink device (step S101). In this case, the connection is either point-to-point or a broadcast connection. Then, a connection management notification command is sent to the source device and/or the sink device (step S102). Wait at the same time (step S103) until the notification response to the connection management change arrives, after receiving the response to the current state from the device receiving the notification command, the bit field change of the corresponding plug control register of the notification command receiver device is received notification response (step S104).

When a response is received in step S104, the change of the online bit field is first checked (step S105). If the online bit field in the bit field in the corresponding plug control register becomes "0", the connection is disconnected (step S106). On the other hand, if the online bit field remains "1" and a dedicated connection is established in step S105, it is checked whether the value of the broadcast connection counter or the p2p counter changes (step S107). If there is a change, the user is notified that this is an overlapping connection and appropriate measures should be taken (S108). If the value of the connection counter does not change in step S107, then check whether the payload in the bit field of the corresponding plug control register changes (step S109), if the payload changes, then the bandwidth should be adjusted (step S110). Then, check whether the adjusted bandwidth can be received by the sink device for inputting data (step S112), otherwise, step S102 continues to transmit the connection management command.

According to the invention, disconnection is allowed when one of the plurality of devices connected by the digital interface is no longer required to transmit output or receive input. Therefore, the bandwidth will not be wasted by establishing unnecessary connections, and only the required bandwidth is used, thus improving the bandwidth usage efficiency.

Also, in the present invention, one device can be immediately notified of several types of status changes (for example, data transmission and reception status, data processing performance) that may occur during data processing by another device, thereby allowing the user Quickly understand state changes that occur in connected devices and act on them.

In addition, the present invention can specify information about whether the source device requires data transfer, and also can indicate changes in the number of sink devices connected to the source device and changes in output and input bandwidths of the source device and the sink device, respectively. For example, if the number of sink devices connected to a source device is increased, the user is informed of this change, so that another device's connection is not allowed if it does not wish to connect there. Therefore, more efficient connection state management can be performed.

Claims (21)

1. A connection management method for managing connections between devices in a network system. In the system, one or more devices that transmit data using a predetermined data transmission format are connected to one or more devices that receive data through a predetermined digital interface. The method includes the following steps: (a) A control device controls a plurality of devices, and notifies the control device of state changes involving established connections that occur in the plurality of devices, and notifies the control device of state changes of established connections The steps of the device are performed in response to a connection management command sent to the controlled device, wherein, If the changed connection counter bit field in the transmitting device indicates a change in the number of devices intended to receive information from the transmitting device, the connection of the device intended to receive If the number of devices to which the sending device receives the message changes and a dedicated connection is established, all but the one or more receiving devices originally associated with the established connection cease to receive the message. 2. The method of claim 1, wherein the command structure of the connection management command includes a representation representing the type of connection register held by the one or more devices. 3. A method as claimed in claim 1 or 2, wherein the controlling device is the party to which the connection has been established. 4. The method according to claim 1 or 2, wherein said predetermined digital interface is IEEE1394 format, and said predetermined data transmission format is IEC 61883 format. 5. The method according to claim 1 or 2, wherein, in step (a), if any bit in the bit field of the output plug control register in the transmitting information device and/or any bit in the input plug control register in the receiving information device Any bit in the bit field has changed, the change is notified to the control device, and, Among them, the output plug control register and the input plug control register are registers that control connections defined in the IEC 61883 format. 6. The method according to claim 1 or 2, wherein, in step (a), if a bit field representing online or offline is changed in the device transmitting data, the change is notified to the control device. 7. The method according to claim 1 or 2, wherein, in step (a), if a bit field representing online or offline is changed in the device receiving data, the change is notified to the control device. 8. The method according to claim 1 or 2, wherein, in step (a), if a change in the payload bit field is followed by a change in the output information bandwidth in the transmitting information device, the change is notified to the control device . 9. A method as claimed in claim 1 or 2, wherein step (a) further comprises the step of: if the number of devices receiving information from the transmitting device increases, in addition to one or more receiving devices originally involved in establishing the connection devices stop receiving messages. 10. A connection management method for managing connections between devices in a network system, comprising the following steps: (a) establishing a connection between a device that transmits information via a predetermined data transfer format and a device that receives information, the two being connected by a predetermined digital interface; (b) sending a connection management command to control the connection management state; and (c) When a response to a connection management state change is received, control the connection according to a connection management command. 11. The method according to claim 10, wherein said predetermined digital interface is in IEEE 1394 format, and the predetermined data transfer format is in IEC 61883 format. 12. The method according to claim 10, wherein, in step (b), the connection management command is in the same format as the notification command in the audio-video/control command transaction set format. 13. The method of claim 10, wherein, in step (c), if any bit field of the input plug control register and/or the output plug control register changes, a response to a connection management state change is received, wherein Both registers are connection control registers defined in the IEC 61883 format. 14. The method of claim 10, wherein, in step (c), if the response indicates a change in a bit field representing online or offline in the device transmitting the information, disconnecting or establishing the connection . 15. The method of claim 10, wherein, in step (c), if the response indicates a change in a bit field representing online or offline in the device receiving the information, disconnecting or establishing the connection . 16. The method of claim 10, wherein, in step (c), if the response indicates a change in the payload bit field, the change is due to a change in the bandwidth of the output information in the device transmitting the information If yes, the connection is disconnected or established according to whether the bandwidth of the output information can be accepted by the device receiving the information. 17. The method of claim 10, wherein, in step (c), if said response indicates a change in the connection counter bit field, the change is due to a change in the number of devices receiving information from the transmitting device , disconnect or establish a connection to the device requesting to receive the information. 18. The method of claim 17, wherein, if the number of devices receiving information from the transmitting device changes and a dedicated connection is established, step (c) further comprises notifying the user to block Steps for other devices to receive information. 19. The method according to claim 10, wherein the connection management command has a command structure including connection register type information and identification information, the connection register type information indicating An output plug control register or an input plug control register in a device receiving information, the identification information is information on an input/output plug for establishing a connection. 20. The method of claim 19, wherein the command structure is appended with operands specifying certain bit fields of the output plug control register and/or the input plug control register. 21. The method of claim 19, wherein the command structure is appended with an operand indicating whether to establish a connection for a special purpose.

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