JPH07212399A - Packet communication system - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] To minimize the occurrence of delay when transferring continuous data. [Structure] In the network 1, a part of the band is allocated to a synchronous transfer mode in which the upper limit of the transfer delay time is guaranteed, and the remaining band is allocated to an asynchronous transfer mode in which the guarantee is not guaranteed. . When a large amount of data is transferred in the synchronous transfer mode, overflow occurs and conversely the transfer delay time increases. Therefore, a certain terminal 2
When establishing a connection in order to transmit continuous data, checks the remaining bandwidth of the synchronous transfer mode on the network 1 and receives the allocation of the bandwidth available in the synchronous transfer mode. When receiving the assignment, the terminal 2 gives priority to the continuous data, packetizes it, and transmits it to the partner terminal in the synchronous transfer mode.
The terminal 1 on the receiving side re-prioritizes the data to which the priority is given.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication system, and more particularly to a system for packet-conducting continuous data between a plurality of terminals connected via a network such as a video conference. .

[0002]

2. Description of the Related Art Conventionally, continuous data such as voice and video is usually communicated by a circuit switching system rather than packet communication. This is because these data have the property that a large amount of data is generated at regular intervals over a long period of time. for that reason,
Even in the case of communication, it is necessary to secure a constant bit rate and transfer with a small delay and fluctuation.
Since these properties are completely different from the store-and-forward type data that requires high reliability such as texts, it is common to send them via separate communication lines and communication methods.

However, in recent years, it has become widespread to handle multimedia with a computer, and it is desired to communicate continuous data such as voice and video as well as text data using an existing computer network. The demands such as are increasing. A method of storing and exchanging data such as voice mail is simply transferred as text data and synchronized with each other at the time of creation / playback. That's not the case if you need to transfer in real time. Therefore, in addition to the network for storage and exchange, a method of laying a circuit-switched dedicated line for voice and video data and transferring them by different routes may be adopted. However, this requires double networks, and the labor and cost are considerable.

Therefore, recently, due to the improvement of the reliability and throughput of the network, let the data, which is required to have the real time property, flow along with the network which was conventionally used to transfer the store and forward type data. The idea came out. Then, packets with two different characteristics, such as storage-and-exchange type packets such as text and packets with continuity such as voice and video, must be transferred on the same network. To do so, consider those characteristics. It is necessary to use the transfer method.
As an existing technology, when the traffic volume of the own terminal is a certain value or more and the traffic volume on the LAN is a certain value or more, by reducing the traffic volume from the own terminal,
A packet video conference communication system that prevents deterioration of image / voice quality due to an increase in end-to-end delay (JP-A-3-2)
70430).

FIG. 10 is a block diagram showing the configuration of the terminal shown in the above-mentioned Japanese Patent Laid-Open No. 3-270430 and its peripherals. In FIG. 10, the terminal 901 connected to the network 902 includes an image codec unit 907,
Audio codec unit 908 and image packet unit 909a
And a voice packet unit 909b, a transfer unit 910, a traffic measurement unit 911, and a traffic control unit 912. An image input unit 903 and an image output unit 904 are connected to the image codec unit 907, and an audio input unit 905 and an audio output unit 90 are connected to the audio codec unit 908.
And 6 are connected.

The traffic measuring unit 911 constantly measures the amount of outgoing traffic from the terminal itself and the amount of transfer traffic on the network 902, and notifies the traffic control unit 912 of the measurement result. Traffic control unit 9
Reference numeral 12 analyzes the traffic measurement result of the traffic measuring unit 911, and when the amount of traffic sent from the own terminal is equal to or more than a threshold and the traffic on the LAN is more than the threshold, the amount of information sent from the own terminal needs to be reduced. Image codec section 907 and audio codec section 9
08 is instructed to reduce the amount of transmitted information. In response to this, the image codec unit 907 lowers the upper limit value of the transmission information amount, and the audio codec unit 908 reduces the transmission information amount.
As a result, it is possible to prevent deterioration of image and audio quality due to an increase in end-to-end delay.

[0007]

However, as described above, when the traffic volume of the own terminal is a certain value or more and the traffic volume on the network is a certain value or more,
With a configuration that only reduces the amount of traffic from its own terminal,
Although it helps prevent delays, the resolution of the image may change or the movement may be chopped during communication. As a result, the image becomes very difficult to see. In addition, when the traffic volume becomes very large, the information volume may drastically decrease and the image may look like a still image.

Therefore, it is an object of the present invention to provide a packet communication system capable of suppressing the occurrence of delay when transferring continuous data.

[0009]

The invention according to claim 1 is
The first band allocated for the synchronous transfer mode in which the upper limit of the transfer delay time is guaranteed within a fixed time, and the second band allocated for the asynchronous transfer mode in which the upper limit of the transfer delay time is not guaranteed. A system in which packets are communicated between a plurality of terminals via a network in which bands are mixed, and when a transfer request in a synchronous transfer mode occurs, before a connection is established between the terminals, the first band Bandwidth allocation means for detecting the remaining bandwidth available at the present time, and bandwidth allocation for allocating the bandwidth for the synchronous transfer mode used for the connection based on the remaining bandwidth detected by the remaining bandwidth detection means Means, a priority granting means for granting priority to packets to be synchronously transferred with the bandwidth allocated by the bandwidth allocating means, and a priority The granted packet and a transfer means for transferring preferentially by synchronous transfer mode.

According to a second aspect of the invention, in the first aspect of the invention, the remaining bandwidth detecting means, the bandwidth allocating means, the priority granting means, and the transferring means are provided in each terminal. And

According to a third aspect of the present invention, in the first aspect of the present invention, a monitor means for collectively monitoring the use status of the network is further provided, and the remaining bandwidth detection means and the bandwidth allocation means are provided in the monitor means. It is characterized by being.

The invention according to claim 4 is the invention according to claim 2 or 3.
In the invention described in (1), the band remaining amount detecting means is a band usage amount storing means for storing the current usage amount of the first band in the network, and when the use of the first band is assigned to any of the terminals. , When the use of the first band is released in any one of the terminal and the adding unit that adds the allocated band amount to the band use amount storage unit,
Subtracting means for subtracting the released bandwidth amount from the bandwidth usage storage means, and subtracting the current bandwidth usage stored in the bandwidth usage storage means from the total amount of the first bandwidth assigned to the network. By so doing, the remaining amount calculation means for calculating the remaining amount of the currently usable first band is included.

According to a fifth aspect of the present invention, in the third aspect of the present invention, the remaining bandwidth detection means is a cumulative addition means for cumulatively adding the sizes of packets transferred on the network in the synchronous transfer mode, and a cumulative addition means. An average usage amount calculating means for calculating an average usage amount of the first band per unit time from the packet size cumulatively added to the adding means, and an average usage amount from the total amount of the first band allocated to the network. And a remaining amount calculation unit for calculating the remaining amount of the currently usable first band by subtracting the average usage amount per unit time calculated by the calculation unit.

According to a sixth aspect of the invention, in the first aspect of the invention, the transfer request in the synchronous transfer mode is the highest priority request, and the bandwidth required by the transfer request is the first band. When the remaining amount is exceeded, a further allocation means for allocating a part of the second band to the first band is further provided.

[0015]

According to the first aspect of the present invention, when the transfer request in the synchronous transfer mode is generated, the maximum value of the transfer delay time is guaranteed within a fixed time before the connection is established between the terminals. Data that can be transferred in the synchronous transfer mode by checking the current remaining amount of bandwidth available in the band and assigning priority to packets that can be transferred within this examined remaining amount of bandwidth Since the quantity is controlled, the first band is not overflowed. Therefore, it is possible to easily suppress the occurrence of delay when transferring continuous type data without being affected by the transfer of accumulated type data.

According to the second aspect of the present invention, the remaining bandwidth detection means, the bandwidth allocation means, the priority assignment means and the transfer means are provided in each terminal, so that the remaining bandwidth management can be performed in each terminal. I can do it.

According to the third aspect of the present invention, the monitoring means is provided with the remaining bandwidth detecting means and the bandwidth allocating means, so that the monitoring means can centrally monitor the usage status of the network.

In the invention according to claim 4, a band use amount storage means is provided, and when the use of the first band is assigned to any one of the terminals, the assigned band amount is stored in the band use amount storage means. When the use of the first band is released by any one of the terminals, the released band amount is subtracted from the band use storage means to obtain the current use amount of the first band in the network. It is arranged to be stored in the band usage amount storage means. Further, by subtracting the current band usage amount stored in the band usage amount storage means from the total amount of the first band allocated to the network, the remaining amount of the first band currently available is calculated. I am trying to do it. Thus, in the invention of claim 4, the remaining amount of the first band can be managed without constantly monitoring the network.

According to the fifth aspect of the present invention, a cumulative addition means for cumulatively adding the sizes of the packets transferred on the network in the synchronous transfer mode is provided, and the first addition is made from the packet size cumulatively added to the cumulative addition means. By calculating the average usage amount of the band per unit time and subtracting the calculated average usage amount per unit time from the total amount of the first band allocated to the network, The remaining amount of the band is calculated. As described above, in the invention of claim 5, the remaining amount of the first band can be easily managed only by monitoring the packet transferred on the network.

In the invention according to claim 6, the transfer request in the synchronous transfer mode is the highest priority request, and
When the bandwidth required by the transfer request exceeds the remaining amount of the first band, by allocating a part of the second band to the first band, the transfer of the high priority packet is interrupted. Can be made.

[0021]

1 is a diagram showing the configuration of a packet communication system according to a first embodiment of the present invention. In FIG.
This packet communication system includes a network 1 and a plurality of terminals 2 connected to the network 1. On the network 1, there are a mixture of a synchronous transfer mode in which the upper limit of the data transfer delay time is guaranteed within a fixed time and an asynchronous transfer mode in which the upper limit is not guaranteed. That is, in the network 1, a part of its band (capacity) is allocated to the synchronous transfer mode, and the remaining band is allocated to the asynchronous transfer mode.

FIG. 2 is a block diagram showing an example of the configuration of each terminal 2 in FIG. In FIG. 2, the terminal 2 is
A data input / output unit 21 to which a user device (not shown) (personal computer, video camera, etc.) is connected, a packet control unit 22, a bandwidth management unit 23, and a network 1.
And a transmission / reception unit 24 connected to.

In the packet communication system having the configuration as shown in FIG. 1, when a certain terminal 2 tries to transfer continuous data such as voice and image, the terminal 2 establishes a connection with a partner terminal. Before the network 1
Check the remaining amount of the bandwidth allocated to the synchronous transfer mode above, allocate the bandwidth for synchronous transfer to continuous data accordingly, and give priority to the data and transfer in the synchronous transfer mode I have to.

More specifically with reference to FIG. 2, when the connection request is input from the user device, the data input / output unit 21 immediately passes it to the packet control unit 22. In response, the packet control unit 22 requests the bandwidth management unit 23 to allocate the bandwidth for synchronous transfer. When the bandwidth management unit 23 refuses the bandwidth allocation, the packet control unit 22 notifies the user device of the allocation and ends the operation. On the other hand, when the band is allocated from the band management unit 23, the connection is established. Once the connection is established,
Of the data input from the data input / output unit 21, continuous data is packetized by the packet control unit 22 and given priority, and then passed to the transmission / reception unit 24. Other data is packetized and passed to the transmission / reception unit 24 without being given priority. The transmission / reception unit 24 transfers data using the synchronous transfer mode in which the upper limit of the transfer delay time is guaranteed for the packets with priority, and the upper limit of the transfer delay time is not guaranteed for the other packets. Transfer data using transfer mode. On the other hand, in the terminal 2 on the receiving side, the packet received by the transmitting / receiving unit 24 is passed to the packet control unit 22. The packet control unit 22 processes the data with the priority right first, and outputs the data to the user device via the data input / output unit 21.

FIG. 3 shows the packet controller 22 in FIG.
3 is a flowchart showing the operation of FIG. Hereinafter, the operation of the packet control unit 22 of FIG. 2 will be described in more detail with reference to FIG. When the packet control unit 22 first receives the user's connection establishment request from the data input / output unit 21 (step S101), the band range (upper limit value and lower limit value) requested for continuous data transfer from the connection establishment request. (Denoted by and) are taken out (step S1)
02). Next, the packet control unit 22 passes the extracted band range to the band management unit 23, and the band management unit 23 concerned.
The band is allocated from the server (step S103).

In step S103, if the bandwidth allocation is rejected by the bandwidth manager 23 (step S104), the packet controller 22 informs the user device that the bandwidth cannot be allocated and the connection establishment cannot be accepted. Notify and end the process (step S10)
5). On the other hand, when the band management unit 23 accepts the band allocation, the packet control unit 22 establishes a connection with the partner terminal (step S106).
After the connection is established, the packet control unit 22 receives the user data from the data input / output unit 21 (step S
107), and it is checked whether or not the data has continuity such as voice and image (step S108). If the received user data is not continuous data, the packet control unit 22 packetizes the user data (step S109) and transfers the packet to the transmission / reception unit 24 (step S111). On the other hand, if the received user data is continuous data, the packet control unit 22 packetizes the user data and gives a mark of priority (step S110), and passes the packet to the transmission / reception unit 24 (step S111). ). Then, the packet control unit 22
Checks whether there is next user data (step S112), and if there is next data, step S107.
Then, the process similar to the above is repeated, and if there is no next data, the connection is terminated and the band management unit 23 is notified that the connection is terminated (step S11).
3).

FIG. 4 is a flow chart showing the operation of the band management unit 23 in FIG. Hereinafter, the operation of the band management unit 23 will be described in more detail with reference to FIG. When the bandwidth management unit 23 receives any request (step S
201), and checks whether the received request is a bandwidth allocation request coming from the packet control unit 22 in the terminal itself (step S202). If the request is a bandwidth allocation request from the inside, the bandwidth management unit 23 determines the bandwidth management table (not shown in the figure) held in its own terminal, but how many terminals 2 currently use the bandwidth for the synchronous transfer mode. Synchronize at the present time by obtaining the amount of bandwidth currently in use from the table that records whether it is being used and subtracting it from the amount of bandwidth that has been previously allocated for synchronous transfer to the entire network 1. The remaining bandwidth available for transfer is obtained (step S203).

Next, the band management unit 23 performs the above step S.
It is judged whether or not the remaining bandwidth obtained in 203 is larger than the maximum value of the required range (step S204), and if larger, the maximum value of the required range is allocated as the amount of bandwidth that can be used for synchronous transfer (step S205). Next, the bandwidth management unit 23
Adds and updates the amount of bandwidth allocated in step S205 to the corresponding entry (entry corresponding to the own terminal) in the bandwidth management table in the own terminal (step S20).
6). Next, the bandwidth management unit 23 passes a request for additional update to the bandwidth management table in the other terminal 2 to the transmission / reception unit 24 (step S207) and causes it to be transmitted to the other terminal 2. As a result, the value of the bandwidth management table in the other terminal 2 is updated. Next, the bandwidth management unit 23 returns the allocated bandwidth amount to the packet control unit 22 (step S208), and ends the processing. In response, the packet control unit 22 executes the above-described processing. On the other hand, when the remaining bandwidth is smaller than the maximum value of the required range, the bandwidth management unit 23 determines whether the remaining bandwidth is greater than the minimum value of the required range (step S209). When the bandwidth remaining amount is larger than the minimum value of the requested range, the bandwidth management unit 23 allocates the total bandwidth remaining amount as the bandwidth amount usable for the synchronous transfer (step S2).
10) and proceeds to step S206. If the remaining bandwidth is smaller than the minimum value of the required range, the bandwidth management unit 23
Returns a rejection of the request that the packet cannot be allocated to the packet control unit 22 (step S211). After that, the band management unit 23 ends the processing.

When it is determined in step S202 that the request received in step S201 is not the bandwidth allocation request coming from the packet control unit 22 in the own end, the bandwidth management unit 23 determines that the request is from another terminal 2. It is checked whether or not the request is an additional update request of the bandwidth management table (step S212). If the request is an additional update request, the bandwidth management unit 23 sets the value of the requested bandwidth in the corresponding entry (the entry corresponding to the terminal 2 that has issued the additional update request) in the bandwidth management table in the own terminal. Is added and updated (step S213). After that, the bandwidth management unit 23
The process ends.

When the request received in step S201 is not the additional update request from the other terminal 2, the bandwidth management unit 23 determines that the request is the packet control unit 22 in its own terminal.
(Step S214). The request is the packet control unit 2 in the own terminal.
If it is the allocation release request from 2, the bandwidth management unit 2
3 deletes the band allocation amount for which the cancellation request has been made from the corresponding entry (entry corresponding to the self terminal) in the band management table in the self terminal (step S215). Next, the bandwidth management unit 23 passes a request for deleting and updating the bandwidth allocation value to the bandwidth management table in another terminal 2 to the transmission / reception unit 24 (step S216). After that, the band management unit 23 ends the processing.

If the request received in step S201 is not a bandwidth allocation release request from the packet control unit 22 in the terminal itself, the bandwidth management unit 23 determines that the request is a bandwidth allocation release request from another terminal 2. It is checked whether there is any (step S217). The request is for another terminal 2
If the request is a bandwidth allocation cancellation request from the bandwidth management unit 2
3 deletes the bandwidth allocation amount for which the release request has been issued from the corresponding entry (entry corresponding to the terminal 2 which has issued the bandwidth allocation release request) in the bandwidth management table in the own terminal (step S218). After that, the bandwidth management unit 23
Ends the processing.

FIG. 5 is a diagram showing the configuration of a packet communication system according to the second embodiment of the present invention. In FIG. 5, the packet communication system includes a network 1 and
A plurality of terminals 200 connected to the network 1,
It is composed of a monitor unit 3 that monitors the usage status of the network 1. As in the embodiment of FIG. 1, in the network 1, a part of its band (capacity) is allocated to the synchronous transfer mode, and the remaining band is allocated to the asynchronous transfer mode.

FIG. 6 is a block diagram showing an example of the configuration of each terminal 200 in FIG. In FIG. 5, the terminal 2
00 is a data input / output unit 21 to which a user device (personal computer, video camera, etc.) not shown is connected.
A packet control unit 22, a bandwidth management unit 230, and a transmission / reception unit 24 to which the network 1 is connected. The bandwidth management unit 230 does not have the function of monitoring the usage status of the network 1 unlike the bandwidth management unit 23 in FIG. In this embodiment, the usage status of the network 1 is monitored by the monitor unit 3.
Are collectively monitoring. The other configuration of the terminal 200 is the same as the configuration of the terminal 20 in FIG.

In the packet communication system having the configuration as shown in FIG. 5, when a certain terminal 200 tries to transfer continuous data such as voice and image, the terminal 20 concerned.
0 transfers the bandwidth allocation request to the monitor unit 3 before establishing the connection with the partner terminal. The monitor unit 3 that has received the request checks the remaining amount of the band that can be used for the synchronous transfer in the network 1, and based on the result, allocates the band to the requesting terminal 200 and transfers the band. The terminal 200 that has received the assignment assigns priority to the continuous data, packetizes the data, and transfers the packet using the synchronous transfer mode.

FIG. 7 is a flow chart showing an example of the operation of the monitor section 3 of FIG. Hereinafter, the operation of the monitor unit 3 of FIG. 5 will be described in more detail with reference to FIG. 7. The monitor unit 3, which captures all the packets flowing on the network 1, receives the packets (step S30).
1) It is checked whether the packet is given a priority (step S302). When the arriving packet is
If the packet is given a priority, that is, a packet sent in the synchronous transfer mode, the monitor unit 3
Record the current time (step S30)
3) Cumulatively add the sizes of the packets that have arrived at the packet counter (not shown, which is provided in the monitor unit 3) used to count the size of the packets to which the priority is given (step S304).

Next, the monitor unit 3 checks whether or not a fixed time has elapsed from the time when the packet size was recorded in the previous packet counter (step S305), and if the fixed time has passed, the current value of the packet counter is checked. Based on the count value and the elapsed time, the amount of the band currently used for synchronous transfer is obtained (step S306). That is, the monitor unit 3 divides the current count value of the packet counter by the elapsed time to obtain the current used bandwidth amount as the average used bandwidth amount within the fixed time period. Next, the monitor unit 3 clears the packet counter and, based on the amount of bandwidth previously allocated for the synchronous transfer to the entire network 1, proceeds to step S306.
By subtracting the currently used bandwidth amount obtained in step 3, the remaining amount of the currently usable bandwidth for synchronous transfer is obtained (step S307). Next, the monitor unit 3 updates the value of the band remaining amount memory (not shown, which is provided in the monitor unit 3) that records the band remaining amount (step S30).
8). Next, the monitor unit 3 returns to step S301 again and repeats the same processing as above.

When it is determined in step S302 that the packet arriving in step S301 is not a packet to which priority is given, the monitor unit 3 checks whether or not the packet is a bandwidth allocation request from the terminal 200 ( Step S309). If it is not the allocation request from the terminal 200, the monitor unit 3 proceeds to step S30.
The procedure returns to 1 and the same processing as above is repeated. On the other hand, terminal 2
If the allocation request is from 00, the monitor unit 3 determines whether or not the remaining bandwidth recorded in the remaining bandwidth memory is larger than the maximum value of the requested bandwidth range (step S310). The maximum value of the request range is assigned as the amount of bandwidth that can be used for synchronous transfer (step S31).
1). After that, the monitor unit 3 determines that the request source terminal 200
Returns the value of the bandwidth amount allocated to (step S31
2) Return to step S301 and repeat the same processing as above. If the remaining bandwidth is not greater than the maximum value of the required range, the monitor unit 3 determines whether the remaining bandwidth is greater than the minimum value of the required range (step S313). Is allocated as a usable bandwidth amount (step S314), and the process proceeds to step S312. When the remaining bandwidth is smaller than the minimum value of the request range, the monitor unit 3 sends back a request refusal that the request source terminal 200 cannot be allocated (step S31).
5) Return to step S301 and repeat the same processing as above.

FIG. 8 is a flowchart showing another operation example of the monitor section 3 of FIG. Hereinafter, another operation example of the monitor unit 3 will be described with reference to FIG. Monitor unit 3
Upon receiving the packet (step S401), checks whether the packet is a bandwidth allocation request from the terminal 200 (step S402). If the received packet is an allocation request from the terminal 200, the monitor unit 3 causes the band remaining amount recorded in the band remaining amount memory (not shown in the monitor unit 3) (for synchronous transfer). It is determined whether or not the remaining bandwidth of the allocated bandwidth is larger than the maximum value of the allocation request range (step S40).
3) If it is larger, the maximum value of the requested range is allocated as a band usable for synchronous transfer (step S404). Next, the monitor unit 3 subtracts the band amount allocated to the terminal 200 from the band remaining amount recorded in the band remaining amount memory (step S405), and sends back the value of the band amount allocated to the request source terminal 200. (Step S406). After that, the monitor unit 3 returns to step S401 and repeats the same processing as above. If the remaining bandwidth is not greater than the maximum value of the required range, the monitor unit 3 determines whether the remaining bandwidth is greater than the minimum value of the required range (step S4).
07), if it is larger than the minimum value of the required range, the total remaining bandwidth is allocated as a usable bandwidth for synchronous transfer (step S408). After that, the monitor unit 3 performs step S40.
Go to 5. When the remaining bandwidth is smaller than the minimum value of the request range, the monitor unit 3 sends back a request refusal that the request source terminal 200 cannot be allocated (step S4).
09), and returns to step S401 to repeat the same processing as above.

If the packet received in step S401 is not an allocation request from the terminal 200, the monitor unit 3
Checks whether or not the request is for de-allocation from the terminal 200 (step S402), and if it is a de-allocation request, adds only the de-allocation request to the remaining band amount recorded in the remaining band memory. (Step S41
1) The confirmation of the cancellation request is sent back to the request source terminal 200 (step S412), the process returns to step S401, and the same processing as above is repeated.

FIG. 9 is a flow chart showing still another operation example of the monitor unit 3 of FIG. Hereinafter, still another operation example of the monitor unit will be described with reference to FIG. When the monitor unit 3 receives the packet (step S50)
1) It is checked whether the bandwidth allocation request is from the terminal 200 (step S502). If the bandwidth allocation request is issued, the bandwidth remaining amount recorded in the bandwidth remaining memory (not shown, but provided in the monitor unit 3). It is determined whether (remaining amount of bandwidth allocated for synchronous transfer) is larger than the maximum value of the allocation request range (step S50).
3) If it is larger, the maximum value of the requested range is allocated as a band that can be used for synchronous transfer (step S504). Next, the monitor unit 3 subtracts the band amount allocated to the terminal 200 from the band remaining amount recorded in the band remaining amount memory (step S505), and sends back the value of the band amount allocated to the request source terminal 200. (Step S506). After that, the monitor unit 3 returns to step S501 and repeats the same processing as above. If the remaining bandwidth is not greater than the maximum value of the required range, the monitor unit 3 determines whether the remaining bandwidth is greater than the minimum value of the required range (step S5).
07), if it is larger than the minimum value of the required range, the total remaining bandwidth is allocated as a usable bandwidth for synchronous transfer (step S508). After that, the monitor unit 3 performs step S50.
Go to 5.

If the remaining bandwidth is smaller than the minimum value of the request range, the monitor unit 3 checks whether or not the bandwidth allocation request is the highest priority request (step S509), and if it is the highest priority request, the network 1 A request is made to allocate the insufficient amount of bandwidth for synchronous transfer from the bandwidth allocated to the asynchronous transfer mode (step S51).
0), record the allocated band (step S51
1) proceeds to step S505. On the other hand, if the request is not the highest priority request, the monitor unit 3 sends back a request rejection indicating that it cannot be allocated to the request source terminal 200 (step S512), returns to step S501, and repeats the same processing as above.

When it is determined in step S502 that the packet received in step S501 is not a bandwidth allocation request, the monitor unit 3 checks whether the packet is a bandwidth allocation cancellation request from the terminal 200 (step S513), and an allocation cancellation request is issued. If so, the amount of band requested to be released is added to the amount of remaining band recorded in the remaining amount of band memory (step S514). Next, the monitor unit 3 checks whether or not the band requested to be released is the band allocated from the asynchronous transfer mode (step S515), and if it is the allocated band, synchronously transfers the recorded band. The network 1 is requested to return from the mode band to the asynchronous transfer mode band (step S516). Next, the monitor unit 3 returns confirmation of the cancellation to the sender of the cancellation request (step S517), returns to step S501, and repeats the same processing as above.

[0043]

According to the invention of claim 1, when a transfer request in the synchronous transfer mode is generated, the maximum value of the transfer delay time is guaranteed within a fixed time before the connection is established between the terminals. In the synchronous transfer mode, the present remaining bandwidth available in the first bandwidth is checked, and the packets that can be transferred within the examined remaining bandwidth are given priority and transferred preferentially. Since the amount of data to be transferred is controlled, the first band does not overflow. Therefore, it is possible to easily suppress the occurrence of delay when transferring continuous type data without being affected by the transfer of accumulated type data.

According to the second aspect of the present invention, the remaining bandwidth detecting means, the bandwidth allocating means, the priority assigning means, and the transferring means are provided for each terminal. You can manage the quantity.

According to the third aspect of the present invention, since the monitoring means is provided with the remaining bandwidth detecting means and the bandwidth allocating means, it is possible to centrally monitor the use status of the network by the monitoring means. .

According to the fourth aspect of the present invention, the band use amount storage means is provided, and when the use of the first band is assigned to any of the terminals, the assigned band amount is stored in the band use amount storage means. And when the use of the first band is released in any of the terminals, by subtracting the released band amount from the band use amount storage means,
The current usage amount of the first band in the network is stored in the band usage amount storage unit, and the current band usage amount stored in the band usage amount storage unit from the total amount of the first band assigned to the network. Since the remaining amount of the first available band is calculated by subtracting, without constantly monitoring the network,
The remaining amount in the first band can be managed.

According to the fifth aspect of the present invention, cumulative addition means for cumulatively adding the sizes of the packets transferred on the network in the synchronous transfer mode is provided, and the first addition is made from the packet size cumulatively added to the cumulative addition means. Of the currently available bandwidth by calculating the average usage per unit of time of the bandwidth of the network and subtracting the average usage per unit of time from the total of the first bandwidth allocated to the network. Since the remaining amount of the first band is calculated, the remaining amount of the first band can be easily managed only by monitoring the packet transferred on the network.

According to the invention of claim 6, when the transfer request in the synchronous transfer mode is the highest priority request, the bandwidth required by the transfer request exceeds the remaining amount of the first band. In this case, since a part of the second band is allocated to the first band, it is possible to interrupt the transfer of a packet having a high priority.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of a terminal in FIG.

FIG. 3 is a flowchart showing an operation of a packet control unit in FIG.

FIG. 4 is a flowchart showing an operation of a band management unit in FIG.

FIG. 5 is a diagram showing a configuration of a packet communication system according to a second embodiment of the present invention.

6 is a block diagram showing a configuration of a terminal in FIG.

7 is a flowchart showing an example of the operation of the monitor unit in FIG.

8 is a flowchart showing another operation example of the monitor unit in FIG.

9 is a flowchart showing still another operation example of the monitor unit in FIG.

FIG. 10 is a block diagram showing a configuration of a terminal and its surroundings of a conventional packet communication system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Network 2, 200 ... Terminal 3 ... Monitor part 21 ... Data input / output part 22 ... Packet control part 23,230 ... Band management part 24 ... Transceiver part

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H04N 7/15 9371-5K H04L 13/00 305 D (72) Inventor Hiroshi Doi Osaka Prefecture Kadoma City 1006 Kadoma Matsushita Electric Industrial Co., Ltd. (72) Inventor Takashi Matsuda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. A first band allocated for a synchronous transfer mode in which a transfer delay time upper limit is guaranteed within a fixed time, and an allocation for an asynchronous transfer mode in which a transfer delay time upper limit is not guaranteed. A system for communicating a packet between a plurality of terminals via a network in which the specified second band is mixed, and when a transfer request in the synchronous transfer mode occurs, before establishing a connection between the terminals. A band remaining amount detecting means for detecting a band remaining amount currently available in the first band; and a synchronous transfer used for the connection based on the band remaining amount detected by the band remaining amount detecting means. Bandwidth allocating means for allocating bandwidth for the mode, priority for packets to be synchronously transferred with the bandwidth allocated by the bandwidth allocating means A packet communication system comprising: a priority granting means for granting a priority and a transfer means for preferentially transferring the packet to which the priority is granted in the synchronous transfer mode. 2. The bandwidth remaining amount detecting means, the bandwidth allocating means, the priority granting means and the transfer means,
The packet communication system according to claim 1, wherein the packet communication system is provided in each of the terminals. 3. The monitor according to claim 1, further comprising monitor means for collectively monitoring the usage status of the network, wherein the bandwidth remaining amount detector and the bandwidth allocation means are provided in the monitor means. Packet communication system. 4. The band remaining amount detecting means includes a band usage amount storing means for storing a current usage amount of the first band in the network, and the usage of the first band in any one of the terminals. An addition unit that, when assigned, adds the assigned band amount to the band usage amount storage unit; and when the use of the first band is released in any of the terminals, the released band amount Means for subtracting from the bandwidth usage storage means, and the first allocation assigned to the network.
Remaining amount calculation means for calculating the remaining amount of the first band that is currently available by subtracting the current amount of band usage stored in the amount of band usage storage means from the total amount of the band. Item 4. The packet communication system according to Item 2 or 3. 5. The bandwidth remaining amount detecting means includes a cumulative addition means for cumulatively adding the sizes of packets transferred on the network in the synchronous transfer mode, and a packet size cumulatively added by the cumulative addition means for calculating the packet size. An average usage amount calculating means for calculating an average usage amount of the first band per unit time; and the first usage amount assigned to the network.
Residual amount calculation means for calculating the remaining amount of the first band that is currently available by subtracting the average used amount per unit time calculated by the average used amount calculation means from the total amount of the band. The packet communication system according to claim 3. 6. When the transfer request in the synchronous transfer mode is the highest priority request and the bandwidth required by the transfer request exceeds the remaining amount of the first band, the first request The packet communication system according to claim 1, further comprising a allocating unit that allocates a part of the second band to the first band.