JP2001186139A - Communication system and management device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system and a management device that can effectively utilize a band, when conducting isochronous communication in compliance with communication standards, such as IEEE 1394. SOLUTION: An IRM 10 refers to a band reservation state table (S108), that stores bands having already been reserved and priority set to communication units reserving the bands, when receiving a band reservation request and when there is no available band in a transmission channel 100, identifies a communication unit whose band release is requested on the basis of the referred band reservation state table (S110) and makes a request to the identified communication unit to release its band.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of communication devices connected to a transmission path serving as a communication medium and performing communication using a predetermined band, and a management device for managing the use status of the bands of these communication devices. Communication system, especially IEEE
The present invention relates to a communication system for performing communication using a high-speed bus interface based on a communication standard defined by E1394 and a management device used for the communication system.

[0002]

2. Description of the Related Art DV (Digital Video) camera, DTV
(Digital Television), CS (Communication Satell)
ite) Tuner and DVCR (Digital Video Cassette)
There is a rapidly growing demand for a home network for connecting home appliances, mainly AV devices such as Recorders). Therefore, various devices can be easily connected, and IEEE 139 capable of transmitting information at high speed.
Attention has been paid to a high-speed bus interface based on the communication standard defined in No. 4.

In communication using a network based on IEEE 1394, isochronous communication in which communication is performed at a fixed period (125 μs) suitable for high-speed communication such as real-time display and asynchronous communication in which communication is performed at an arbitrary time alternately. Done.

FIG. 5 is a time chart conceptually showing isochronous communication and asynchronous communication using an IEEE 1394 bus interface. In FIG. 5, the horizontal axis indicates the passage of time, and isochronous communication and asynchronous communication are performed at a cycle of 125 μs. During 125 μs, isochronous communication is allocated at most 100 μs, and the remaining 25 μs is allocated to asynchronous communication.

[0005] A transmitting apparatus for transmitting transmission information such as video information by isochronous communication uses a communication resource (isochronous resource) reserved in advance, that is, a channel assigned as an identifier and the amount of information that can be transmitted. Transmission is performed using a packet based on the determined band. In isochronous communication, first, a cycle start packet for notifying that isochronous communication is started is transmitted, and then transmission information based on the secured channel and band is transmitted as a packet. The destination of each packet transmitted in the isochronous communication is not specified, and the receiving device receives the transmission information based on the channel of the packet.

[0006] In the asynchronous communication, a transmitting device transmitting information transmits a packet designating a receiving device, and the receiving device receives the packet and returns an acknowledgment (ack) to the transmitting device.

[0007] In the isochronous communication using the IEEE 1394 bus interface as described above, it is necessary to manage communication resources that can be used on a network. , IRM).

[0008] The IRM manages the bandwidth by using BANDWIDTH_AV.
This is performed using a register called an AILABLE register (hereinafter referred to as a BAR). This BAR stores the remaining amount of bandwidth that can be used on the network. When receiving a request for securing a band from the communication device, the IRM refers to the BAR and determines whether or not the band required by the communication device can be secured.

[0009] If the band required by the communication device cannot be secured because the remaining band available on the network is insufficient, the current isochronous communication is performed. It is necessary to request the communication device to release the band. However, the BAR does not store information indicating which communication device of the plurality of communication devices connected to the transmission path has secured the band. Therefore, in the conventional IRM, a band release request is issued to all the communication devices connected to the transmission path.

[0010]

However, as described above, when the IRM issues a band release request to all communication devices connected to the transmission path, a plurality of communication devices receiving the release request receive a request. When a device releases a band, a band more than necessary may be released. As a result, an unnecessary band is secured in the transmission path, and there is a problem that the band may not be effectively used.

The isochronous communication performed by each communication device includes low-priority communication that does not cause any inconvenience even if the communication is interrupted, and importance that causes a problem if the communication is interrupted. There is a high communication. For example, isochronous communication performed by a surveillance camera for monitoring the state of the front door is considered to be a low-priority communication because there are many cases where there is no particular problem even if interrupted. The isochronous communication that is performed is considered to be a highly important communication because a problem occurs in that the transmission information cannot be recorded while the communication is interrupted. As described above, conventionally, all communication devices connected to the transmission path are uniformly requested to release the band, so that there is a problem that isochronous communication with high importance is interrupted.

[0012] The present invention has been made in view of such circumstances, and the IRM performs bandwidth management based on bandwidth securing information indicating the bandwidth securing status, thereby enabling effective use of bandwidth. It is an object to provide a system and a management device.

Another object of the present invention is to provide a communication system which does not interrupt high-priority communication by managing a band based on a priority determined for each communication device.

[0014]

A communication system according to a first aspect of the present invention includes a plurality of communication devices that communicate with each other via a transmission line using a predetermined band, and are connected to the transmission line, and are connected to the transmission line. A management device that manages a bandwidth that can be used by the communication device, the communication device includes a reservation request transmission unit that transmits a band reservation request to the management device; A communication device that secures the bandwidth, and a storage unit that stores bandwidth securing information in which the secured bandwidth is paired, and when a bandwidth securing request is received, the bandwidth related to the received securing request is provided. When the communication device that requests the release of the band is specified based on the band securing information stored in the storage unit, and the release of the band is performed to the communication device specified by the specification unit. request Characterized in that it comprises a release request transmitter for transmitting.

According to a sixth aspect of the present invention, there is provided a management apparatus for managing a band which can be used by a communication device connected to a transmission line on said transmission line, wherein said communication device secures a band. And, comprising a storage unit that stores the band securing information that is a set of the secured band, in the case of receiving a band securing request, when the bandwidth related to the received securing request could not be secured, Specifying means for specifying a communication device requesting release of a band based on the band securing information stored in the storage unit, and transmitting a release request for transmitting a release request of the band to the communication device specified by the specifying unit Means.

According to the first and sixth aspects of the invention, the communication device transmits a request for securing a band required for the communication to the management device before performing the communication. The management device stores bandwidth securing information in which a communication device that has already secured the bandwidth and the secured bandwidth are paired. Then, when a bandwidth reservation request is received from the communication device, if the bandwidth corresponding to the received reservation request cannot be secured, the communication device that requests the release of the bandwidth is specified based on the stored bandwidth securing information. Then, a band release request is transmitted to the specified communication device.

As described above, since the management device can specify the communication device that requests the release of the band based on the state of securing the band, all the communication devices connected to the transmission line as in the conventional case can be specified. As compared with the case where a band release request is made, the band more than necessary is not released, and the band can be effectively used.

A communication system according to a second aspect of the present invention is the communication system according to the first aspect, wherein the communication device includes a band release unit that releases the reserved band when receiving the band release request. The communication device that has requested the securing of the bandwidth includes a bandwidth securing unit that secures the released bandwidth.

According to the second aspect, the communication device that has received the band release request from the management device releases the reserved band, and the communication device that has requested the band reservation secures the released band. . Therefore, the communication device that has requested the reservation of the band can transmit desired transmission information using the reserved band.

In a communication system according to a third aspect of the present invention, in the communication system according to the first or second aspect, the band securing information includes a priority set in advance for a communication device that secures the band. Is further included.

A communication system according to a fourth aspect of the present invention is the communication system according to the third aspect, wherein the communication device includes a storage unit for storing the priority, and the securing request transmission unit is stored in the storage unit. The priority is transmitted to the management device together with the bandwidth reservation request.

According to the third aspect, the band securing information stored in the management device includes the communication device that has already secured the band, the communication device that has secured the band, and the communication device that has secured the band. This is a set of priorities set in advance for the device.

According to the fourth aspect, each communication device stores the priority set for the communication device, and stores the priority when making a request for securing a band to the management device. The priority is also transmitted.

As described above, the priority is determined in advance for each communication device, and the management device specifies the communication device to which the band release request is to be transmitted based on the priority. Bandwidth can be released without interrupting high communication.

Also, each communication device stores this priority, and the stored priority is transmitted to the management device together with the request for securing the band, so that the management device can easily store the priority for each communication device. Can be obtained.

A communication system according to a fifth aspect of the present invention is the communication system according to any one of the first to fourth aspects, wherein the communication via the transmission line is an isochronous communication based on a communication standard defined by IEEE1394. It is characterized by being.

According to the fifth aspect, the communication via the transmission path performed between the communication devices is isochronous communication based on a communication standard defined by IEEE1394. Therefore, various devices can be easily connected, and high-speed information can be transmitted.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. FIG. 1 is a block diagram showing the configuration of the communication system of the present invention. In FIG. 1, 1
0 indicates an IRM for managing isochronous resources of each communication device in isochronous communication. As shown in FIG. 1, the IRM 10 has a CPU 11, and the CPU 1
1 is a transmission line 1 based on the IEEE 1394 standard.
The communication unit 12 is connected to a storage unit 13 for storing information such as programs and data. Further, the storage unit 13 has a BAR 14 for storing a remaining amount of a band used for isochronous communication performed on the transmission path 100. Further, the storage unit 13 stores a band securing status table storing information indicating the bandwidth securing status. The IRM 10 operates as the management device of the present invention by executing a program stored in the storage unit 13.

In the transmission line 100, as a communication device,
A DV camera 20, a DTV 30, a CS tuner 40, and a DVCR 50 described below are connected respectively.

The DV camera 20 is a communication device including an image pickup means 22 for picking up an image, a storage unit 23 for storing information such as programs and data, and a communication means 24 connected to the transmission path 100. By executing a program stored in the storage unit 23 by the CPU 21 that controls an imaging instruction or the like to the image processing apparatus 22, the apparatus operates as the communication device of the present invention. In the present embodiment, the DV camera 20 transmits the video imaged by the imaging unit 22 to the DTV 30 as transmission information.

The DTV 30 includes a display means 32 for displaying transmission information received via the transmission line 100 as video data.
And a storage unit 3 for storing information such as programs and data
3 and a communication unit 34 connected to the transmission path 100. The CPU 31 that controls display instructions and the like to the display unit 32 executes a program stored in the storage unit 33 to execute this program. It operates as the communication device of the invention. In the present embodiment, DTV 30
It is assumed that the transmission information received from the DV camera 20 is displayed on the display unit 32.

The CS tuner 40 includes a receiving unit 42 for receiving an image distributed from a communication satellite, a storage unit 43 for storing information such as programs and data, and a communication unit 44 connected to the transmission line 100. The device operates as a communication device of the present invention by executing a program stored in the storage unit 43 by a CPU 41 that controls a reception unit 42 to perform a reception instruction and the like. In the present embodiment, the CS tuner 40 transmits the video received by the receiving unit 42 to the DVCR 50 as transmission information.

The DVCR 50 is connected to the recording unit 52 for recording the transmission information received via the transmission line 100 on a DVC (Digital Video Cassette), a storage unit 53 for storing information such as programs and data, and to the transmission line 100. This is a communication device including a communication unit 54, and operates as a communication device of the present invention by executing a program stored in a storage unit 53 by a CPU 51 that controls reception instructions and the like for a recording unit 52. In the present embodiment, the DVCR 50 records the transmission information received from the CS tuner 40 on the DVC by the recording unit 52.

Each of the various communication devices described above stores a priority determined based on the importance of isochronous communication performed by each communication device in a storage unit provided in each communication device. This priority can be arbitrarily set by the user. For example, a user can set a high priority to a communication device with a high use frequency and set a low priority to a communication device with a low use frequency. In addition, isochronous communication performed by a recording device such as the DVCR 50 has a problem that, if the communication is interrupted, a task of recording transmission information cannot be performed. Therefore, a high priority is given to such a recording device. May be set.

In addition, a low priority can be set for a communication device having a wide band required for isochronous communication, and a high priority can be set for a communication device having a narrow band. That is, in the present embodiment, the DV cameras 20 and D
If it is assumed that the isochronous communication performed between the TVs 30 requires 30 Mbps and the isochronous communication performed between the CS tuner 40 and the DVCR 50 requires 10 Mbps, the user needs the CS tuner 40 and the DVCR 50 for the DV camera 20 and the DTV 30. Set a higher priority than Each communication device may store a predetermined priority as a default value in advance, and the user may change the setting as necessary.

FIG. 2 is a conceptual diagram showing an example of the format of the band securing status table stored in the storage unit 13 of the IRM 10. As shown in FIG. 2, three fields of a communication device name field 101, a used bandwidth field 102, and a priority field 103 are prepared.

The communication device name field 101 stores the name of a communication device for which a band is secured. Further, the bandwidth used by the communication device is stored in the used bandwidth field 102, and the priority field 103 is stored in the priority field 103.
The priority set for the communication device is stored.

The IRM 10 is connected to the transmission line 1 as described later.
If the available bandwidth is insufficient at 00, the communication device requesting the release of the bandwidth is specified based on the information stored in the bandwidth securing status table.

Next, the flow of the bandwidth securing processing in the communication system of the present invention will be described. In the following description, the flow of operation of the communication system of the present invention when the DV camera 20 secures a band will be described as an example. The process of securing a channel functioning as an identifier in isochronous communication is the same as the process defined by the IEEE 1394 standard, and a description thereof will not be repeated. FIGS. 3 and 4 are flowcharts showing the processing of the IRM 10 and the DV camera 20 and the communication device required to release the band when the DV camera 20 secures the band in the communication system of the present invention.

The DV camera 20 refers to the priority stored in the storage unit 23 when transmitting the video imaged by the imaging means 22 to the DTV 30 by isochronous communication (S201). Then, the bandwidth required for transmitting the video and the priority referred to in step S201 are transmitted to the IRM 10 as a bandwidth securing request (S20).
2).

When the IRM 10 receives the bandwidth reservation request (S101), the IRM 10 refers to the BAR 14 of the storage unit 13 (S102) and determines whether there is a remaining available bandwidth in the transmission path 100 (S102). S103). If it is determined that there is a remaining band (YES in S103),
The bandwidth indicated in the bandwidth securing request received in step S101 is secured (S104).

Next, the IRM 10 adds a new record to the bandwidth securing status table based on the bandwidth securing request received in step S101 (S105), and is stored in the BAR 14 based on the bandwidth secured in step S104. The remaining amount of the band that can be used in the transmission line 100 is updated (S106). Then, secure success information indicating that the bandwidth has been secured is transmitted to the DV camera 20 (S
107).

The DV camera 20 receives the reservation success information from the IRM 10 (S203). As a result, isochronous communication can be performed using the reserved band.

On the other hand, if it is determined in step S103 that there is no remaining band (NO in S103), the IRM 10
Refers to the band securing status table stored in the storage unit 13 (S108). Then, it is determined from the referred band securing status table whether or not there is a communication device (hereinafter, referred to as a release target device) that secures a band wider than the band related to the band securing request received in step S101 (S109). ). Here, when it is determined that there is a device to be released (YES in S109), the communication device having the lowest priority set among the devices to be released (hereinafter, referred to as the minimum priority device) is specified (S110). Then, a band release request is made to the specified lowest priority device (S11).
1).

The communication device specified as the lowest priority device receives the release request from the IRM 10 (S30).
1), the reserved band is released (S302), and band release information indicating that the band has been released is transmitted to the IRM 10 (S303).

When the bandwidth release information is received (S112), the IRM 10 secures the bandwidth related to the received bandwidth release information (S113), and deletes the record related to the bandwidth-released communication from the bandwidth reservation information table (S114). ). Then, the reserved band is compared with the band related to the band securing request received in step S101, and it is determined whether the band necessary for the DV camera 20 to perform the isochronous communication has been secured (S115). Here, if it is determined that it has been secured (YES in S115), the above-described steps S105 to S107 are executed. As a result, the DV camera 20 can perform isochronous communication using the reserved band.
On the other hand, if it is determined in step S115 that the band necessary for the DV camera 20 to perform isochronous communication cannot be secured (NO in S115), the process returns to step S109.

If it is determined in step S109 that there is no device to be released (NO in S109), the IRM1
0 transmits to the DV camera 20 securing failure information indicating that the securing of the band has failed (S116).

The DV camera 20 receives the reservation failure information from the IRM 10 (S204). In this case, the DV camera 20 displays an error indicating that the isochronous communication cannot be performed because the band cannot be secured, and notifies the user of the error display. Further, the band securing request (S202) may be executed again after a predetermined time.

The above-described processing is not limited to the case where the DV camera 20 secures the band, and the same processing is naturally performed when the other communication devices secure the band.

As described above, in the communication system of the present invention, when it is necessary to release the bandwidth, the IRM 10 refers to the bandwidth securing status table, requests the appropriate communication device to release the bandwidth, and secures the bandwidth. Therefore, the band can be effectively used.

Further, since the communication device requesting the release of the bandwidth is specified based on the priority, the communication device performing the isochronous communication with high importance does not interrupt the communication.

In the present embodiment, the IEEE 1394
Although the form applied to the communication system based on the standard was shown,
The present invention is not limited to this, and may be in any form based on any standard that can perform the same processing.

[0053]

As described above, in the management apparatus and the communication system according to the present invention, the IRM manages the bandwidth based on the bandwidth securing information indicating the bandwidth securing status, thereby achieving effective use of the bandwidth. Becomes possible.

Also, by managing the bandwidth based on the priority determined for each communication device, the present invention has an excellent effect such that the communication of high importance is not interrupted.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a communication system according to the present invention.

FIG. 2 is a conceptual diagram showing an example of a format of a band securing status table.

FIG. 3 is a flowchart showing a process performed by the IRM, the DV camera, and a communication apparatus which is required to release a band when the DV camera secures a band in the communication system of the present invention.

FIG. 4 is a flowchart showing a process of the IRM and the DV camera and a communication device required to release a band when the DV camera secures a band in the communication system of the present invention.

FIG. 5 is a time chart conceptually showing isochronous communication and asynchronous communication using an IEEE 1394 bus interface.

[Explanation of symbols]

 Reference Signs List 10 Isochronous resource manager 14 BAR 20 DV camera 30 DTV 40 CS tuner 50 DVCR 100 Transmission line

Claims (6)

[Claims] 1. A plurality of communication devices that communicate with each other via a transmission path using a predetermined band, and are connected to the transmission path,
A communication device comprising: a management device that manages a band that can be used on the transmission path; wherein the communication device includes a securing request transmission unit that transmits a band securing request to the management device; The apparatus includes a communication device that secures a band, and a storage unit that stores bandwidth securing information in which the secured bandwidth is paired, and when a bandwidth securing request is received, the received securing is performed. Specifying means for specifying a communication device requesting the release of a band based on the band securing information stored in the storage unit when the band associated with the request cannot be secured; and a communication device specified by the specifying unit. And a release request transmitting unit for transmitting a band release request to the communication system. 2. The communication device, further comprising: a band release unit that releases a reserved band when receiving the release request of the band, wherein the communication device that has requested the reservation of the band includes the released band. The communication system according to claim 1, further comprising a band securing unit for securing bandwidth. 3. The communication system according to claim 1, wherein the band securing information further includes a priority set in advance for a communication device that secures the band. . 4. The communication device includes a storage unit that stores the priority, and the reservation request transmitting unit transmits the priority stored in the storage unit to the management device together with the band reservation request. 4. The communication system according to claim 3, wherein the communication system is adapted to do so. 5. The communication via the transmission path is performed according to an IEEE standard.
The communication system according to any one of claims 1 to 4, wherein the communication is isochronous communication based on a communication standard defined in 1394. 6. A management device that manages a band that can be used by a communication device connected to a transmission line on the transmission line, wherein: a communication device that secures a band; A storage unit for storing band securing information in which a band is set, and when a band securing request is received, and when a band related to the received securing request cannot be secured, the band is stored in the storage unit. A communication device that requests a release of a band based on the allocated band securing information; and a release request transmission unit that transmits a release request of the band to the communication device specified by the specification device. Management device.