JP3327761B2 - Communications system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system capable of dynamically changing an allocated communication band, and more particularly, each data transmitted using different communication channels has relevance. If so, the present invention relates to a communication system capable of dynamically changing a communication band in consideration of the association.

[0002]

2. Description of the Related Art Generally, a communication system includes a management node that manages a communication state of the communication system and a general node that performs data communication with another general node existing in the communication system. Here, each general node is
The management node has a function of notifying each communication capability to the management node and a function of executing data communication based on communication band information included in a management packet notified from the management node. Multiple general nodes are the same if they have the function of calculating the communication band of each general node based on the communication capability of the node and the communication state in the communication system, and the function of broadcasting the calculation result to each general node. It is possible to dynamically control the allocation of the communication band when sharing the communication system.

For example, in the channel band management processing system described in Japanese Patent Laid-Open Publication No. 05-153154, the band allocated to the communication channel is dynamically controlled as described below. The communication system has a monitoring function of monitoring the amount of communication bandwidth used for each communication channel and a control function of controlling the amount of communication bandwidth of the communication channel. When there is a communication band amount that can be allocated to the communication channel, the monitoring function determines whether or not the communication band amount currently allocated to this communication channel is used at a predetermined usage rate or more. The control function newly allocates a predetermined bandwidth amount if the communication channel uses a communication bandwidth amount equal to or higher than a predetermined usage rate.

Meanwhile, there is a so-called TV conference system described in Japanese Patent Laid-Open No. 02-192487. In the TV conference system described in this publication, a speech request switch is allocated to each attendee who attends the conference in advance, and the attendee who speaks during the conference operates the speech request switch. In response to this operation, the TV
The camera moves so that the image of the speaker can be input, and distributes the input image to other stations participating in the conference.

[0005]

In the above-described channel band management processing method, it is determined whether or not to increase the communication band amount according to the usage rate of the communication band amount for each communication channel. However, when transmitting related data using independent communication channels (for example, image information and audio information), the communication bands allocated to these communication channels cannot be simultaneously controlled. However, there is a problem that the communication band cannot be increased for the other communication channel, but the communication band cannot be increased for the other communication channel.

[0006] In addition, the TV conference system as described above
The operation of the speaker request switch by the speaker is an essential requirement. Therefore, depending on the timing of the operation of the utterance request switch by the speaker, there is a problem that the audio data is distributed, but the video data cannot be distributed to another station at a desired timing.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a communication system capable of simultaneously controlling the communication bandwidth of each communication channel when related information is transmitted using different communication channels. It is. Another object of the present invention is to provide a communication system capable of distributing audio data and video data to another station at the same timing.

[0008]

Means for Solving the Problems and Effects of the Invention The structure of the present invention for achieving the above object will be described below. However, in order to clarify the correspondence with the embodiment of the invention described later, the present invention is described. The reference numerals of the corresponding parts are given to the respective components adopted in. However, it should be pointed out in advance that this reference number is given for ease of understanding and reference only and does not limit the scope of the claims of the present invention.

A first aspect of the present invention is a communication system in which a single management node and a plurality of general nodes are connected via a transmission line. In the communication system, each general node transmits data to be transmitted by the general node. Information saving means for saving information on the number of communication channels to be used, priority information of the communication channel, and information on whether or not there is coordination between the communication channels;
An information notification unit that notifies the management node of each piece of information saved in the first saving unit, wherein the management node communicates with the management node saving unit that receives information saved from each general node and saves the information; A monitoring unit that monitors whether or not the transmission data is transmitted using the channel, and further saves the result of the monitoring; priority information of the communication channel saved by the management node saving unit; Based on the presence / absence information of the linkage and the monitoring result of the monitoring means,
A packet creation / notification means for determining a communication band to be allocated to each general node at regular intervals, generating a bandwidth management packet including the determined communication band, and notifying all general nodes of the packet; A bandwidth saving unit that saves the communication band of the own node included in the bandwidth management packet; and an allocating unit that assigns the communication band saved by the bandwidth saving unit to a communication channel used for transmitting transmission data. In the communication system having the above configuration, the communication band allocated to the general node is increased in accordance with the usage state of the communication band amount for each communication channel. At this time, the general node notifies the management node in advance of the presence / absence information of the relationship between the communication channels,
Even in the case of transmitting related data using independent communication channels, the communication bands allocated to these communication channels can be simultaneously increased.

According to a second aspect of the present invention, when the transmission data is video data and audio data related to the video data, the information saving means includes priority information of a communication channel used for transmitting the video data and the audio data. And the presence / absence information having interlock between the communication channels are saved, and the packet creation / notification unit determines that the communication channel used for transmitting the voice data is used according to the monitoring result of the communication channel monitoring unit. When it is determined, the communication band is determined in consideration of the coordination between the communication channels used for transmitting the video data and the audio data, and the communication used for transmitting the audio data is determined based on the monitoring result of the communication channel monitoring unit. If it is determined that the channel is not used, the communication channel used to transmit the video data and the audio data is used. And determining a communication band without considering the linkage between panel. According to the above configuration, when the general node has transmitted the video data without actually using the communication channel used for transmitting the audio data, lower the priority of allocating the communication band to the general node, When a general node uses a communication channel used for transmitting audio data and video data, it is possible to increase the priority of allocating a communication band to the general node. As a result, in a TV conference system or the like, a large number of communication bands are allocated to a communication channel used to transmit video data of a conference participant who is speaking (using an audio channel). It becomes possible to transmit. Furthermore, since the communication channels used for transmitting these are set to be linked, it is possible to transmit audio data and video data at substantially the same timing.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the overall configuration of a communication system according to one embodiment of the present invention. In FIG. 1, a management node 1 and a plurality of general nodes 2 (two shown in the figure) are connected to a communication system via a transmission line.

The management node 1 includes a management node transmitting / receiving unit 11, a communication node channel configuration information saving unit 12,
Communication channel monitoring unit 13 and bandwidth management packet creation unit 1
4 and a bandwidth management packet notification unit 15. Less than,
The configuration of the management node 1 will be described. The management node transmission / reception unit 11 receives a bandwidth request packet (details will be described later) transmitted from all the general nodes 2 at the time of starting the communication system. Alternatively, a bandwidth management packet (details will be described later) created inside the management node 1 is broadcast to all the general nodes 2. The general node channel configuration information saving unit 12 saves all band request packets received by the management node transmitting / receiving unit 11. The communication channel monitoring unit 13 constantly monitors a communication channel used by the general node 2. Here, each general node 2 allocates a communication channel to a communication band allocated by a method described later, and transmits transmission data to another general node using this communication channel. At this time, the transmission data packet including the transmission data includes information of a communication channel used for transmitting the transmission data packet (hereinafter, referred to as communication channel information).
The communication channel monitoring unit 13 monitors the communication channel, extracts this channel information, and saves it. The bandwidth management packet creation unit 14 is a communication node channel configuration information saving unit 12
On the basis of each band request packet saved in the communication channel monitoring unit 13 and the channel information saved in the communication channel monitoring unit 13.
The communication band of each general node 2 is calculated. After calculating the communication bandwidths of all the general nodes, the bandwidth management packet creation unit 14 creates a bandwidth management packet that includes them collectively. The band management packet creating unit 14 has a timer for measuring a fixed period internally, and shifts to a process of creating a band management packet every fixed period. The created bandwidth management packet is output to the bandwidth management packet notification unit 15. The bandwidth management packet notification unit 15 broadcasts the bandwidth management packet to all the general nodes 2 via the management node transmitting / receiving unit 11.

Each general node 2 has its own node channel configuration saving section 22 and its own node channel configuration information notifying section 23.
, Its own node channel band saving unit 24, a channel generation unit 25, and a general node transmission / reception unit 26.
The own node channel configuration saving unit 22 saves total channel number information, priority information for each communication channel, and linked channel information for each channel used by each general node 2. Here, the total channel number information is the total number of communication channels required by each general node 2 in the subsequent transmission of the transmission data packet. The priority information is the priority of the communication channel required by the general node 2. More specifically, the priority information is information that defines a communication band required by a transmission data packet transmitted using a communication channel. Linked channel information is information indicating whether or not there is a relationship between transmission data packets transmitted using different communication channels in a communication channel set by the general node 2. For example, in a TV conference system and the like, video data and audio data for transmitting a moving image are transmitted using different communication channels, respectively. However, the video data and the audio data are data that are related to each other. is there. Information indicating such a relationship is referred to as linked channel information. The own node channel configuration information notifying unit 23 includes the own node channel configuration saving unit 22.
A communication request packet (see FIG. 2) including the own node channel configuration information is created on the basis of the information saved in the above. This communication request packet is created only when starting up the communication system.

Here, the bandwidth request packet will be described. FIG. 2 is a diagram illustrating an example of the content of information saved in the own node channel configuration saving unit 22. In FIG. 2, the own node channel configuration saving unit 22 communicates with the general node 2 to notify the management node 1 of total channel information, priority information, and interlocking channel information necessary for transmission of subsequent transmission data packets. The channel identifier C and the priority information P (C) are stored in association with each other. In the content example shown in FIG. 2, the general node 2 having N1 as the identifier of the general node 2 is the
Are set as C11 and C12. Further, the general node 2 sets “1” as the priority information P (C) corresponding to C11. “P (C11) +1” is set as the priority information P (C) corresponding to C12. Here, a term “P (C11)” is added to the priority information P (C) corresponding to C12 in order to indicate the interlocking channel information with the communication channel C11.

Referring again to FIG. 1, the general node 2 will be described. The general node transmitting / receiving unit 24 transmits the created bandwidth request packet to the management node 1. Alternatively, it receives a bandwidth management packet transmitted from the management node 1 and outputs it to the own node channel bandwidth saving unit 25. Further, a transmission data packet including the transmission data 21 is transmitted to another communication node. The own node channel band saving unit 25 saves a communication band related to the own node included in the input band management packet as a communication band usable by the own node in the next cycle. The channel generation unit 26 allocates a communication band that can be used by the own node to a communication channel in the next cycle based on the band management packet, and generates a transmission data packet including the transmission data 21.

FIG. 3 is a diagram showing an example of the contents of information saved in the general node channel configuration information saving unit 12. The information (see FIG. 2) transmitted from each general node 2 is saved in the general node channel configuration saving unit 12. FIG.
, Each piece of information transmitted from the general node 2 having the identifiers N1 and N2 is stored.

FIG. 4 is a diagram showing an example of the content of information in which the communication channel monitoring unit 13 monitors the use status of the communication channel and saves the monitoring result. In FIG. 4, as a result of monitoring by the communication channel monitoring unit 13, the channels C11 and C1
2 and C21 are actually used.

FIG. 5 is a diagram showing an example of the content of a bandwidth management packet created by the bandwidth management packet creation unit 14. The bandwidth management packet includes the identifier of each general node 2 and the occupation rate of the communication band allocated to each general node 2. The bandwidth management packet shown in FIG. 5 is created based on the information shown in FIG. Channel C1 in FIG.
The priorities P (C) of 1, C12 and C21 are “1”, “P (C11) +1” and “1”, respectively. Therefore, the communication bands allocated to the general nodes having the identifiers N1 and N2 are those in which the priorities are proportionally distributed. Therefore, the general node having the identifier N1 has {P (C11) + P (C12)} / {P (C11)
+ P (C12) + P (C21) + P (C22)} = 0.
75 is assigned to the general node having the identifier N2, {P (C21) + P (C22)} / {P (C11)
+ P (C12) + P (C21) + P (C22)} = 0.
25 are assigned. Here, since the general node 2 having the identifier N2 does not use the communication channel C22, P (C22) = "0" in the above two equations. P (C11) = 1, P (C12) = P (C1
1) + 1 = 2, P (C21) = 1, and P (C22) = 0.

FIG. 6 is a flowchart showing a procedure of band control in the communication system. FIG. 7 is a flowchart showing a detailed procedure of “creation of a bandwidth management packet (step S66)” shown in FIG.

Hereinafter, the operation of the communication system will be described with reference to FIGS.

First, a system reset of the communication system is executed (step S61), and the management node 1 and each general node 2 are started. At this time, the management node 1
Allocates a preset communication band to each general node 2. This communication band is for enabling each general node 2 to transmit a band request packet in the next step S62.

In each of the general nodes 2 activated in response to the system reset, the own node channel configuration information notifying section 2
3 creates a bandwidth request packet based on the information saved by the own node channel configuration saving unit 22 (see FIG. 2). The general node transmitting / receiving unit 24 transmits the bandwidth request packet to the management node 1. As a result, the own node channel configuration information is notified to the management node 1 (step S62).

The management node transmitting / receiving unit 11 outputs the bandwidth request packets received from all the general nodes 2 to the general node channel configuration information saving unit 12. The general node channel configuration information saving unit 12 saves all band request packets (step S63). For example, it is assumed that there are two general nodes 2 in the communication system, and one of them has an identifier N1 and the other has an identifier N2. The general node 2 assigned the identifier N1 notifies the management node 1 of the bandwidth request packet shown in FIG.
The general node 2 to which the identifier N2 has been assigned, as in the case shown in FIG. 2, processes the bandwidth request packet in which the priorities “1” and “P (C21) +1” are included in the channels C21 and C22, respectively. When the management node 1 is notified in the processing in S62, the general node channel configuration information saving unit 12 saves information as shown in FIG.

The management node 1 proceeds to the processing in step S66 and creates a bandwidth management packet (step S6).
6). In the first “creation of a bandwidth management packet”, the bandwidth management packet creation unit 14 creates a bandwidth management packet based only on the information saved in the general node channel configuration saving unit 12 (see FIG. 3). At this time, the bandwidth management packet creation unit 14 transmits the priority information P shown in FIG.
The communication band is proportionally distributed based on the numerical value of (C). The management node 1 assigns the bandwidth occupancy “0.5” to the general node 2 having the identifier N1 according to the following equation (1). {1 + P (C11) +1} / {1+ (P (C11) +1) +1+ (P (C21) +1)} = 0.5 (1) The bandwidth management packet generator 14 of the management node 1 calculates the following equation (2) ), The bandwidth occupancy “0.5” is assigned to the general node 2 having the identifier N2. {1 + P (C21) +1} / {1+ (P (C11) +1) +1+ (P (C21) +1)} = 0.5 (2) The bandwidth management packet generator 14 calculates the above equations (1) and (2) ), And generates a bandwidth management packet based on the calculation result.
Output to The bandwidth management packet notification unit 15 broadcasts the bandwidth management packet to all the general nodes 2 via the management node transmitting / receiving unit 11.

This bandwidth management packet is received by the general node transmitting / receiving units 26 of all the general nodes 2. The general node transmitting / receiving unit 26 outputs a band management packet to the own node channel band saving unit 24. The own node channel band saving unit 24 saves the occupancy of the communication band of the own node included in the band management packet (step S68). Accordingly, the channel generation unit 2
5 generates a transmission data packet including transmission data 21 to be transmitted to another general node 2, allocates a communication channel based on the occupation rate of the communication band, and outputs the communication channel to the general node transmitting / receiving unit 26. This transmission data packet is transmitted from the general node transmitting / receiving unit 26 to another general node 2 (step S69). As described above, this transmission data packet stores communication channel information indicating communication channel C.

When transmission of a transmission data packet from the general node 2 starts, the management node 1 determines whether or not to stop the communication system by a determination unit not shown in FIG. 1 (step S70). If the determination unit determines that the communication system is not to be stopped, the process proceeds to step S64. The communication channel monitoring unit 13 extracts communication channel information from a transmission data packet transmitted on the transmission path via the management node transmission / reception unit 11 and saves the information. For example, the general node 2 having the identifier N1 transmits a transmission data packet using the communication channels C11 and C12, and the general node 2 having the identifier N2 transmits a transmission data packet using the communication channel C21. Then, the communication channel monitoring unit 13 saves the communication channel information as shown in FIG.

The band management packet generator 14 determines whether a predetermined period has elapsed by using an internal timer (step S65). At this time, if the predetermined period has not elapsed, the process proceeds to step S70. The management node 1 determines whether to stop the communication system by using a determination unit (not shown in FIG. 1) (step S7).
0). If the determination unit determines that the communication system is not to be stopped, the process proceeds to step S64. On the other hand, when the predetermined period has elapsed, the processing shifts to the processing in step S66.

When creating the second and subsequent bandwidth management packets, the bandwidth management packet creation unit 14 creates the bandwidth management packet according to the procedure shown in FIG. Hereinafter, a procedure for creating a bandwidth management packet will be described with reference to FIG.

The bandwidth management packet creating unit 14 designates the general node 2 based on the identifier of the general node 2 saved in the communication node channel configuration information saving unit 12 (step S71). The bandwidth management packet creating unit 14 searches whether the specified identifier of the general node 2 is saved in the communication channel monitoring unit 13. If the identifier of the general node 2 has been saved in this search, the bandwidth management packet creation unit 14 determines that the general node 2 uses the communication channel, and shifts to the processing in step S73. On the other hand, if the identifier of the general node 2 has not been saved, it is determined that the general node 2 does not use the communication channel, and the process proceeds to step S81. The bandwidth management packet creation unit 14 sends the general node 2
Determines that they are not using a communication channel,
A default value is set as a priority coefficient of the general node 2 in order to allocate only a predetermined minimum communication band to the general node 2 (step S8).
1).

In the process at step S73, the band management packet creating unit 14 specifies a communication channel based on the communication channel information saved by the communication channel monitoring unit 13 (step S73), and associates the communication channel with the link channel information. Is determined with reference to the communication node channel configuration information saving unit 12 (step S7).
4). At this time, if the interlocked channel information is not set for the specified communication channel, the bandwidth management packet creating unit 14 sets this communication channel as the priority information of this communication channel and uses the priority information as the priority coefficient of this communication channel in step S77 (described later). Move to On the other hand, the bandwidth management packet creation unit 14
If the interlocked channel information has been set for the specified communication channel, the process proceeds to step S75.

The band management packet creating unit 14 determines whether or not the communication channel linked to the designated communication channel is currently used by referring to the communication channel monitoring unit 13 (step S75). At this time, when the communication channel linked to the specified communication channel is not currently used, the band management packet creating unit 14 sets this communication channel as the priority information of this communication channel using the priority information as a priority coefficient in step S77 (described later). Move to the processing of. On the other hand, if the communication channel linked to the specified communication channel is currently used, the bandwidth management packet creating unit 14 proceeds to step S7.
Then, the process proceeds to step S6.

The band management packet creating unit 14 adds the priority information of the interlocking channel to the priority information of the designated communication channel (step S77), and saves the result of the addition as a communication channel priority coefficient.

Next, the bandwidth management packet generator 14 adds the previous added priority coefficient of the general node 2 to step S7.
Then, the priority coefficient obtained in the process in step 7 is added (step S77).

When the processing in step S77 is completed, the band management packet creating unit 14 determines whether or not the processing in steps S73 to S77 has been executed for all communication channels of the general node 2 specified in the processing in step S71. A determination is made (step S78). At this time, if the above processing has not been executed for all communication channels, the processing from step S73 to step S77 is newly executed.
On the other hand, if the above processing has been executed for all communication channels, the addition result obtained in the processing in step S77 is saved inside as the priority coefficient of the general node 2, and the processing shifts to the processing in step S79.

When the processing in step S78 is completed, the bandwidth management packet creating unit 14 determines whether or not the processing in steps S71 to S78 has been executed for all the general nodes 2 (step S79). At this time, if the above processing has not been executed for all the general nodes 2, the processing from step S71 to step S78 is newly executed. On the other hand, if the above process has been executed for all the general nodes 2, the process proceeds to step S80.

The bandwidth management packet creating section 14 creates a bandwidth management packet (see FIG. 5) by proportionally allocating the communication bandwidth to each general node 2 based on the priority coefficients of all the general nodes 2 saved inside. (Step S80), and outputs the result to the bandwidth management packet notification unit 15.

The communication system will be described again with reference to FIG. The bandwidth management packet creation unit 14 outputs the bandwidth management packet created in the processing in step S66 to the bandwidth management packet notification unit 15. The bandwidth management packet is broadcast to all the general nodes 2 via the management node transmitting / receiving unit 11 (step S67). This bandwidth management packet is received by the general node transmitting / receiving units 26 of all the general nodes 2. The general node transmitting / receiving unit 26 includes the own node channel band saving unit 24
To output a bandwidth management packet. The own node channel band saving unit 24 saves the communication band information assigned to the own node included in the band management packet (step S68). In response to this, the channel generation unit 25 creates a transmission data packet including the transmission data 21 to be transmitted to another general node 2 and based on the communication band information saved in the own node channel band saving unit 24. A communication channel is allocated and output to the general node transmitting / receiving unit 26. This transmission data packet is transmitted from the general node transmitting / receiving unit 26 to another general node 2 (step S69).

When transmission of a transmission data packet from the general node 2 starts, the management node 1 determines whether or not to stop the communication system by a determination unit (not shown in FIG. 1) (step S70). If the determination unit determines that the communication system is not to be stopped, the process proceeds to step S64. Thereafter, in the present communication system, the processes in steps S64 to S70 are repeatedly executed, and in the process in step S70, if the determination unit determines to stop the communication system, the communication in the present communication system ends.

As described above, in the present communication system, the usage status of the communication channel is monitored at regular intervals, and if the communication band allocated last time is not used by the general node, the general node will A required communication band (default value) is allocated, and the remaining communication band is allocated to a general node using a communication channel to dynamically change the communication band.

In the above embodiment, the interlocking channel information is set between the two communication channels used by the same general node 2, but the communication channel used by a certain general node 2 and the communication channel used by another general node 2 are set. It may be set between communication channels to be used, or may be set between three or more communication channels. In addition, although each of the general nodes 2 sets the interlocking channel, the management node 1 may set them collectively. In the above-described embodiment, the priority information of another communication channel is simply added as the priority information of the communication channel. However, any relational expression other than the addition may be applied.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating an example of the content of information saved in a self-node channel configuration saving unit 22;

FIG. 3 is a diagram showing an example of the content of information saved in a general node channel configuration information saving unit 12.

FIG. 4 is a diagram showing an example of the content of information in which a communication channel monitoring unit 13 monitors the use status of a communication channel and saves the monitoring result.

FIG. 5 is a diagram showing an example of the content of a bandwidth management packet created by a bandwidth management packet creation unit 14;

FIG. 6 is a flowchart showing a procedure of band control in the communication system.

FIG. 7 shows a “bandwidth management packet (step S6) shown in FIG.
6) is a flowchart showing a detailed procedure of “Creation of 6)”.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Management node 11 ... Management node transmission / reception unit 12 ... General node channel configuration information saving part 13 ... Communication channel monitoring part 14 ... Band management packet creation part 15 ... Band management packet notification part 2. General node 21 ... Transmission data 22 ... Own Node channel configuration saving section 23: own node channel configuration information notifying section 24: own node channel band saving section 25: channel generating section

Continuation of the front page (56) References JP-A-3-58646 (JP, A) JP-A-2-73742 (JP, A) JP-A-2-10982 (JP, A) JP-A-7-135504 (JP) JP-A-5-153154 (JP, A) JP-A-4-207343 (JP, A) JP-A-60-112357 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB H04L 5/00-5/12 H04L 12/00-12/56 H04J 1/00-1/20 H04J 4/00-15/00

Claims (2)

(57) [Claims] 1. A communication system in which a single management node and a plurality of general nodes are connected via a transmission line, wherein each of the general nodes uses a communication that the general node uses to transmit transmission data. An information saving unit that saves channel number information, priority information of the communication channel, and information on presence / absence of coordination between the communication channels, and notifies the management node of each information saved in the first saving unit. Information notifying means, the management node comprising: a management node saving means for receiving and saving information notified from each of the general nodes; and whether or not each of the general nodes transmits transmission data using a communication channel. Monitoring means for monitoring whether or not the result of the monitoring is further saved; priority information of the communication channel saved by the management node saving means; Based on the presence / absence information of the mobility and the monitoring result of the monitoring means, a communication band to be allocated to each of the general nodes is determined at regular intervals, and a bandwidth management packet including the determined communication band is created. Each of the general nodes further includes a band saving unit that saves a communication band of the own node included in the band management packet, and a communication that the band saving unit saves. Allocating means for allocating a band to a communication channel used for transmission of transmission data. 2. When the transmission data is video data and audio data related to the video data, the information saving means includes communication channel priority information used for transmitting the video data and the audio data. And the presence / absence information with which the communication channels are linked, wherein the packet creation / notification unit uses a communication channel used for transmitting the voice data based on the monitoring result of the communication channel monitoring unit. If it is determined that the communication data is transmitted, the communication band is determined in consideration of the coordination between the communication channels used for transmitting the video data and the audio data. If it is determined that the communication channel used to transmit the video data is not used, the video data and Serial and determines the communication bandwidth without considering the linkage between communication channel used to transmit voice data, the communication system according to claim 1.