JPH10322346A - Network communication system and band reservation method used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the network communication system by which a reserved band width is flexibly decided and th band reservation in a communication path between terminals is established for a short period. SOLUTION: In the network communication system having pluralities of terminals and pluralities of repeaters 2, a message packet for band reservation is communicated on a communication path between the terminals 1, and in the case that the band width able to be reserved in common by all connections of the communication path (remaining bands) is more than a band (minimum required band) required by communication between the terminals 1 by the communication of the message packet, each repeater 2 on the communication path reserves the band width to be reserved by setting a desired band width (desired band) requested for the communication between the terminal 1 as an upper limit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network communication system in which terminals perform data communication via a relay device, and more particularly to a network communication system having a function of securing a transmission bandwidth for data communication, and a network communication system having the same. It relates to the bandwidth reservation method used.

[0002]

2. Description of the Related Art In a connectionless type network communication system, a function for securing a desired transmission bandwidth and performing packet communication includes IETF (Internet Entrance).
gineering Task Force), RSVP (Reso
urce Reservation Protocol) is known. RSVP
Is incorporated in the terminals and the relay device that constitute the network, and performs bandwidth reservation by message communication.
An example of a bandwidth reservation procedure in a communication system including RSVP will be described with reference to FIGS.

In FIG. 20, at the start of communication, a terminal 1-1 on the transmitting side of a data packet transmits a path message 96-1 in which data representing the format of the data packet and required traffic characteristics are set. Terminal 1 of
And send it to address 2. This path message 96-1 is
The data is sequentially transferred by the relay device 2 such as a router, and is transferred to the receiving terminal 1-2 through a communication path uniquely determined by the arrangement of the transmitting and receiving terminals 1. In the example of FIG. 20, the relay devices 2-1, 2-2, 2-3, and 3-4 sequentially transfer path messages.

The receiving terminal 1 that has received the path message 1
2 returns the reservation message 97-5 in which the traffic characteristic data required by the path message is set, to the terminal 1-1 on the transmission side. This reservation message is transferred in the reverse direction on the route to which the path message was sent.

[0005] Each of the relay devices receiving the reservation message,
A desired bandwidth represented by the data of the traffic characteristics set in the reservation message is secured for the connection to which the path message has been transferred, and the reservation message is transferred only when the connection can be secured. Thereby, when a desired bandwidth is secured in all the relay devices on the communication path,
The reservation message is transferred to the transmission side terminal 1-1, and the band reservation is established.

[0006] The transmitting terminal 1 which has received the reservation message 1
1 starts transmission of the data packet 99 with the desired bandwidth represented by the traffic characteristic data. Further, the terminal 1-2 on the receiving side thereafter periodically transmits a reservation message having the same content, and keeps securing the bandwidth on the communication path.

[0007] If there is a relay device on the communication path that cannot ensure the desired bandwidth, the transfer of the reservation message is stopped, and the transmitting terminal 1-1 cannot start transmitting the data packet 99. . For example, the relay device 2-
In the case where the bandwidth cannot be secured, the reservation error message 98 is returned from the relay device 2-3 to the receiving terminal 1-2, as shown in FIG. Thereafter, transmission of the reservation message is also stopped, and the bandwidth secured on the communication path is released.

[0008]

In actual data packet communication, there are many cases where communication can be performed without problems even with a bandwidth smaller than a desired bandwidth. However, according to the above-described conventional method, if there is a relay device that cannot secure a desired bandwidth on a communication path, the bandwidth reservation is not established, and the transmitting terminal does not perform data communication until the bandwidth reservation is established. There must be.

Accordingly, an object of the present invention is to provide a network communication system that flexibly determines a bandwidth to be reserved and establishes a bandwidth reservation in a communication path between terminals in a short period of time.

[0010]

In order to achieve the above object, the present invention comprises a plurality of terminals, one or more relay devices, and a transmission line connecting the terminals and the relay devices. Communication between the terminals is uniquely determined between the terminals,
A network communication system performed through one communication path formed by the transmission path and a relay apparatus, wherein each relay apparatus monitors a free bandwidth of each transmission path, and a first bandwidth. Message communication means for communicating, on a communication path between the terminals, a message packet for bandwidth reservation, including information designating a second bandwidth having a value smaller than the first bandwidth. In a case where the bandwidth that can be commonly secured in all the connections of the communication path by the communication of the message packet is equal to or larger than the second bandwidth, the first bandwidth is set in each relay device on the communication path. Using a bandwidth securing means for securing a bandwidth that can be secured for the connection of the communication path and a bandwidth commonly secured on the communication path, To provide a network communication system, comprising a data communication means for communicating Tapaketto.

In this network communication system, even if there is a relay device on the communication path that cannot secure the first bandwidth (desired bandwidth), the second bandwidth (minimum required bandwidth) When the above bandwidth can be secured in common, the bandwidth is secured and the bandwidth reservation is established.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a connection example of a network communication system according to an embodiment of the present invention. The network communication system in FIG. 1 includes a plurality of terminals 1, a plurality of relay devices 2, and a plurality of transmission lines 3 connecting these devices 1 and 2. This network communication system is basically a connectionless network provided with, for example, IP (Internet Protocol), but has a bandwidth reservation function (protocol) for performing communication with guaranteed bandwidth. . Here, communication between the terminals 1 is relayed by at least one relay device 2. In addition, some transmission paths 3 are used simultaneously for communication on a plurality of communication paths.

The communication between the terminals 1 is performed by the transmission path 3 between the terminals.
The communication is performed via a communication path that minimizes the communication cost determined by the length of the communication path. The communication route is determined based on, for example, cost information registered in the relay device. In the example of FIG.
Communication between the terminal 1-1 and the terminal 1-2 is performed by the relay devices 2-1 and 2-1.
2-2, 2-3, and 2-4, and a transmission line 3 connecting them
-1, 3-2, 3-3, 3-4, 3-5 via one communication path.

Here, an outline of a procedure of a bandwidth reservation performed in the communication system will be described.

In FIG. 1, terminal 1-1 is a data packet transmitting side, and terminal 1-2 is a data packet receiving side. When starting the communication in which the bandwidth is guaranteed, the transmitting terminal 1-1 transmits a bandwidth request message 91 for requesting the reservation of the bandwidth to the receiving terminal 1-2. The transmitted band request message 91 is transferred on the above communication path and received by the receiving terminal 1-2.

The receiving terminal 1-2 having received the bandwidth request message 91 returns a bandwidth reservation message 92 for reserving a bandwidth. In this bandwidth reservation message 92, information on a plurality of types of bandwidths is set. The band reservation message 92 is transferred in the reverse direction on the communication path to which the band request message 91 has been transferred, toward the transmitting terminal 1-1.

When each of the relay devices 2 on this communication path receives the band reservation message 92, the band reservation message 9
2 secures the bandwidth designated by the device 2 and, if it is secured, transfers the bandwidth reservation message 92 to the next relay device (or transmitting terminal). At this time, each relay device 2 secures a bandwidth that can be secured with the desired bandwidth as an upper limit. As a result, even when there is a relay device 2 that cannot secure a desired bandwidth on the communication path, a bandwidth reservation is established, and communication is started using the bandwidth that is commonly secured on the communication path. However, if the minimum bandwidth required for communication between the terminals 1 cannot be secured, the reservation error message 9
3 is returned to the receiving side terminal 1-2, and the band reservation is not established.

Next, the configuration of each device constituting the network communication system will be described.

FIG. 2 is a diagram showing a configuration example of the relay device 2.

In FIG. 2, a relay device 2 includes a band reservation unit 4 for processing and managing a band reservation, a plurality of line interface units 5 connected to another relay device or terminal via a transmission line, It has a routing processing unit 6 for making the above determination and the like, and a bus 7 for interconnecting the above units.

FIG. 3 shows the internal configuration of the bandwidth reservation unit 4.
As illustrated, the bandwidth reservation unit 4 includes a reservation management unit 40, a processor 43, a memory 44, a bus interface unit 4.
5, a timer 46, and a bus 47.
The processor 43 operates according to the program in the memory 44, and performs processing and management of the bandwidth reservation using the reservation management unit 40 and the timer 46.

FIG. 4 shows a reservation management unit 40 in the band reservation unit 4.
2 shows the internal configuration of FIG. As shown, the reservation management unit 40
Is constituted by a reservation management table 41 and a reservation waiting queue 42. The reservation management table 41 includes an identifier 411 of a connection for which a bandwidth is to be reserved, a previous transfer source address 412 indicating a previous transfer source of the connection,
Next transfer destination address 4 indicating the next transfer destination of the connection
13, a reserved band 414 indicating the bandwidth actually secured by the relay device for the connection, a release waiting band 415 indicating a bandwidth additionally required to perform more desirable communication, and a reservation. The wait flag 416 is recorded. The previous transfer source address 412 and the next transfer destination address 413 are determined based on the transfer direction (forward direction) of the data packet. For example, in the relay device 2-2 on the communication path, the previous transfer source address indicates the relay device 2-1 and the next transfer destination address is the relay device 2-3.
Is shown.

FIG. 5 shows the internal configuration of the line interface unit 5. In FIG. 5, the line interface unit 5 includes:
A bus interface unit 50 for connecting to the bus 7 of the relay device 2; a reception buffer 51 for waiting for output of a received packet to the bus interface unit 50; a transmission buffer 52 for waiting for packet transmission; A packet transmission control unit 53 that performs control for transmitting data packets according to the width.
Here, the packet transmission control unit 53 knows the reserved bandwidth from the reserved bandwidth 414 recorded in the reservation management table 41 in the bandwidth reservation unit 4.

FIG. 6 is a diagram showing a configuration example of a portion related to communication of the terminal 1.

In FIG. 6, a terminal 1 performs a line interface unit 5 connected to a relay device 2 via a transmission line, a band reservation unit 14 for processing and managing a band reservation, and a process for transmitting and receiving data. Application unit 13
And an internal bus 17 for connecting the components. In addition, as the terminal 1, for example, a computer having a communication function can be used.

FIG. 7 shows the internal configuration of the bandwidth reservation unit 14 of the terminal 1. The bandwidth reservation unit 14 performs the bandwidth reservation management table 1
40, a processor 143, a memory 144, a bus interface unit 145, and a timer 146. The processor 143 operates according to the program in the memory 144, and performs processing and management of the bandwidth reservation using the bandwidth reservation management table 140 and the timer 146. At this time, the timer 146 is used for measuring the transmission interval of the bandwidth reservation message. Line interface unit 5 of terminal 1
Has the same configuration as the line interface unit 5 of the relay device 2 described with reference to FIG. 5, and operates in the same manner.

FIG. 8 shows the configuration of the reservation management table 140 in the bandwidth reservation unit 14. Registered in the reservation management table 140 are a connection identifier 140-1, a destination address 140-2, a desired band 140-3 indicating a desired bandwidth to be secured by communication, and a reserved band 140-4. Is done.

Next, messages transmitted in the network communication system will be described.

FIG. 9 is a diagram showing a format of a message for bandwidth reservation. As shown in the figure, the message 90 includes a header section 901 and a plurality of object sections 902 following the header section. Header part 9
01, as shown in FIG.
, A flag 901-2, a message type 901-3 indicating the type of the message, and a checksum 901-4.
TTL (Time To Live) 901-5 indicating the lifetime of the message in the network;
01-6 is set. Although not shown,
Address information including the address of the terminal 1 on the data transmission side, the address of the terminal 1 on the data reception side, the previous transfer source address, and the next transfer destination address is also set.

As shown in FIG. 11, the object section 902 has an object length 90 indicating the length of the object.
An object header section 902-1 including an object class 901-1-2 indicating an object type and an object element 902-2 are set. Object element 90 constituting the message
In 2-2, parameters necessary for performing bandwidth reservation are set. The content of the parameter differs depending on the type of the message.

In the object element 902-2 of the bandwidth request message 91, information for specifying the format of the data packet transmitted by the transmitting terminal 1-1, information for specifying the required traffic characteristics, and the like are set.

In the object element 902-2 of the bandwidth reservation message 92, a value of a desired bandwidth (desired bandwidth) desired to be secured in communication and a minimum bandwidth (minimum required bandwidth) required in communication are set. A value and a value of a bandwidth (requested bandwidth) commonly secured on a path between the receiving terminal 1 and the like are set. Note that the transmitting side terminal 1 transmits the bandwidth request message 91
, The values of the desired band and the minimum required band may be specified. Further, the values of the desired band and the minimum necessary band are determined based on, for example, the data type (moving image data, audio data, and the like) of the communication target data, the quality class, and the like.

In the object element 902-2 of the reservation error message 93, a value of the bandwidth (that is, the reserved band) secured by the relay device 2 that has transmitted the reservation error message is set.

Next, a specific example of a procedure for reserving a band in the communication system will be described.

FIGS. 12 and 13 show the transmitting terminal 1-1.
FIG. 9 is a sequence diagram of bandwidth reservation on a communication path between the communication terminal and the receiving terminal 1-2. In the example of FIG. 12, only the free bandwidth of the transmission path 3-3 between the relay devices 2-2 and 2-3 is less than the value of the desired bandwidth (however, not less than the value of the minimum required bandwidth).

In FIG. 12, the transmitting terminal 1-1 transmits a bandwidth request message 91-a-1 to the receiving terminal 1-2 before transmitting a data packet. The transmitted band request message 91-a-1 is transmitted to each of the relay devices 2-1 to 2-4 on the communication path.
-A-2 to 91-a-5, which are sequentially transferred and received by the receiving terminal 1-2.

Upon receiving the band request message 91-a-5, the receiving terminal 1-2 receives the band reservation message 92-a-5.
a-5 is returned to the transmitting terminal 1-1. In the bandwidth reservation message 92-a-5, a desired bandwidth value, a minimum required bandwidth value, and a required bandwidth value determined based on the content of the received bandwidth request message 91-a-5 are set. Have been. At this time, the value of the required band is set equal to the value of the desired band. Thereafter, the receiving terminal 1-2 periodically transmits the bandwidth reservation message to the transmitting terminal 1-1.

Upon receiving the bandwidth reservation message 92-a-5, the relay apparatus 2-4 reserves a bandwidth for the transmission path 3-4 connecting the relay apparatus itself and the relay apparatus 2-3 of the previous transfer source. More specifically, the value of the free bandwidth (remaining bandwidth) for which the transmission path 3-4 is not reserved is equal to or greater than the value of the required bandwidth (= desired bandwidth) of the bandwidth reservation message 92-a-5. The bandwidth of the transmission path 3-4 is secured by the value of the required bandwidth. Then, the bandwidth reservation message 92-a-
A bandwidth reservation message 92-a-4 having the same content as that of the message No. 5 is transmitted to the relay device 2-3.

The relay device 2-3 which has received the bandwidth reservation message 92-a-4 transmits to the transmission line 3-3 connected to the previous transfer source.
Is equal to or greater than the value of the minimum required bandwidth of the bandwidth reservation message 92-a-4 and less than the value of the desired bandwidth, the bandwidth is secured for the transmission path 3-3 by the value of the remaining bandwidth. . Then, a reservation error message 93-a-4 in which the reserved bandwidth value is set is transmitted to the receiving terminal 1-2, and the bandwidth reservation message 92 in which the requested bandwidth value is updated to a value equal to the reserved bandwidth. -A-3 is transmitted to the relay device 2-2.

In the relay device 2-2, since the value of the remaining bandwidth of the transmission path 3-2 is equal to or greater than the value of the required bandwidth of the bandwidth reservation message 92-a-3, the value of the required bandwidth for the transmission path 3-2 is Bandwidth reservation message 92-a
And transmits a bandwidth reservation message 92-a-2 having the same contents as the message -3 to the relay device 2-1. The relay device 2-1 also transmits a band reservation message 92-a-1 having the same content as the received band reservation message 92-a-2 to the transmitting terminal 1-1.
At this time, the requested bandwidth set in the bandwidth reservation message 92-a-1 indicates a bandwidth that is commonly secured in the communication path.

Upon receiving the bandwidth reservation message 92-a-1, the transmitting terminal 1-1 receives the bandwidth reservation message 92-a-1.
a-1 using the bandwidth of the requested bandwidth of a-1.
2. Transmission of a data packet to the second packet is started. And
The transmitted data packet is transferred to the receiving terminal 1-2 with the bandwidth guaranteed.

The error message 93-a-4 is transferred to the receiving terminal 1-2 by the relay device 2-4. At this time, the relay device 2-4 may reduce the bandwidth secured for the connection to the value of the reserved bandwidth of the error message 93. In this case, it is possible to eliminate the need for securing a bandwidth more than necessary, and to enable effective use of the transmission path.

After the transmission of the data packet is started, the relay apparatus 2-3 which cannot secure the bandwidth by the value of the required bandwidth,
Increase the bandwidth to be secured. That is, the bandwidth secured by another connection is released, and the transmission path 3-
3, when the remaining bandwidth occurs, the relay device 2-3, upon receiving the bandwidth reservation message 92-c-4, transmits the
For 3, the bandwidth is additionally secured up to the value of the desired bandwidth. Then, a bandwidth reservation message 92-c-3 in which the value of the requested bandwidth is updated to a value equal to the total value of the secured bandwidth is transmitted to the relay device 2-2. The above relay device 2-3 is
The bandwidth to be secured may be independently added without receiving the bandwidth reservation message 92-c-4. However, in this case, the reserved bandwidth is notified to another relay device 2 by a bandwidth reservation message or a reservation error message.

In the relay apparatus 2-2, the bandwidth of the transmission path 3-2 is additionally secured so as to be equal to the value of the required bandwidth of the received bandwidth reservation message 92-c-3, and the bandwidth reservation of the same content is performed. Send message 92-c-2 to the previous transfer source.
This bandwidth reservation message is sent to the transmitting terminal 1-1 via the relay device 2-1. Then, the transmitting side terminal 1-1
Continues transmission of data packets according to the bandwidth of the new required bandwidth value set in the received bandwidth reservation message.

The value of the actually secured bandwidth may be limited to a predetermined value. For example, for the bandwidth reservation message, a plurality of bandwidths (alternate bandwidths) having different values are set instead of the desired bandwidth value and the required minimum bandwidth value. Then, each relay device 2 secures the bandwidth of only the value of the largest alternative band that is equal to or less than the bandwidth that can be secured by the relay device 2 among the respective alternative bands. In this case, the addition of the reserved bandwidth is performed according to the value of the alternative bandwidth.

On the other hand, in the example of FIG.
The value of the remaining bandwidth of the transmission path 3-3 is less than the value of the minimum required bandwidth of the bandwidth reservation message. When receiving the bandwidth reservation message 92-a-4, the relay device 2-3 determines that the value of the remaining bandwidth of the transmission path 3-3 is less than the value of the minimum required bandwidth of the bandwidth reservation message. Is not transmitted, the reservation error message 93-a is not sent.
-4 is returned. This also cancels the registration in the relay device 2-4 which has already secured the band.

Next, a description will be given of a specific process of each device capable of performing the above operation.

First, the reception processing of the band reservation message in the receiving terminal 1-2 will be described with reference to the flowchart of FIG.

The receiving terminal 1-2 first determines a destination address, a desired bandwidth, a minimum required bandwidth, and a reserved bandwidth from the setting contents of the received bandwidth reservation message, and stores the destination address in the reservation management table 140 (FIG. 10). 8) to determine whether the corresponding connection is registered (step 1815). If there is no corresponding registration, the connection identifier and the determined information are newly registered in the reservation management table 140 (step 1825). If there is a corresponding registration, the registration content of the connection is updated to the determined information (step 1820). Next, the receiving terminal 1-2 transmits a bandwidth reservation message in which the requested bandwidth is set equal to the desired bandwidth to the transmitting terminal 1-1 (steps 1830, 184).
0), and the process ends.

Next, the process of receiving a bandwidth reservation message in each relay device 2 will be described with reference to the flowcharts of FIGS.

When receiving the bandwidth reservation message (step 1110), the relay device 2 determines whether the next transfer destination of the bandwidth reservation message is the transmitting terminal 1-1 (step 1112). Next transfer destination is sender terminal 1
If the value is -1, the bandwidth reservation message 92 is transferred to the transmitting terminal 1-1 (step 1114), and the process ends.

If the next transfer destination is not the transmitting terminal 1-1, the relay apparatus 2 determines whether or not the corresponding connection is registered in the reservation management table 41 (step 1120). If there is no registration in the reservation management table 41, the connection identifier, the previous transfer source address, and the next transfer destination address are determined and newly registered in the reservation management table 41 (step 1130). Then, an unused bandwidth (remaining bandwidth) in the transmission path 3 connecting the own relay apparatus 2 and the previous transfer source relay apparatus 2 is obtained, and the value of the remaining bandwidth and the value of the required bandwidth of the bandwidth reservation message are obtained. Are compared with each other (step 1140).

When the value of the remaining bandwidth is equal to or greater than the value of the required bandwidth,
Since the required bandwidth can be secured, the value of the reserved bandwidth secured by the own device is set as the required bandwidth value (step 122).
0), the value of the reserved band is set in the reservation management table 41 (step 1230). Then, a bandwidth reservation message having the same content is transmitted to the relay device 2 of the previous transfer source address (step 1240), and the process ends.

If the value of the remaining bandwidth is less than the value of the required bandwidth in step 1140, the remaining bandwidth is compared with the minimum required bandwidth of the received bandwidth reservation message (step 1150). If the value of the remaining bandwidth is smaller than the value of the minimum required bandwidth, the reservation of the bandwidth is abandoned, the value of the reserved bandwidth is set to 0 (step 1255), and a reservation error message is returned to the device of the next transfer destination address (step 1260). ).
Then, the registration of the connection in the reservation management table 41 is deleted (step 1265), and the process is terminated.

If the value of the remaining bandwidth is equal to or greater than the minimum required bandwidth in step 1150, the bandwidth desired for communication cannot be secured, but the required minimum bandwidth can be secured. For this reason, the relay device 2 sets the value of the reserved band to the value of the remaining band (step 1160), sets the value of the band to be released to the value obtained by subtracting the reserved band from the band to be requested (step 1170), and furthermore, The value of the requested bandwidth is set as the value of the reserved bandwidth (= the value of the remaining bandwidth) (step 118).
0). Then, by setting the identifier of the connection in the reservation waiting queue 42, the band release wait is registered (step 1190). In the registration of the connection in the reservation management table 41, each value of the reserved band and the release wait band is set. Is added, and a valid value is set in the reservation waiting flag 416. Then, a bandwidth reservation message in which the value of the requested bandwidth is updated is transmitted to the relay device 2 of the previous transfer source address (step 12).
10), end the process.

Next, the processing A at the branch destination in step 1120 will be described with reference to FIG. In the process A, the bandwidth to be reserved is added.

When the registration of the relevant connection is confirmed in step 1120, the relay device 2 first
It is determined whether the reservation waiting flag 416 of the connection in the reservation management table 41 is a valid value (step 1410). If the valid value has not been set, it is determined whether or not the value of the requested bandwidth of the received bandwidth reservation message is equal to or less than the value of the reserved bandwidth secured by the own device (step 1420). When the value of the requested bandwidth is equal to or less than the value of the reserved bandwidth, it is not necessary to add the bandwidth to be reserved.
80), end the process.

If the value of the required bandwidth is larger than the value of the reserved bandwidth in step 1420, the value of the bandwidth to be released is changed to the value of the required bandwidth set in the bandwidth reservation message.
As a difference from the value of the reserved bandwidth set in the reservation management table 41 (step 1470), the value of the release wait band is set in the reservation management table 41, the effective value is set in the reservation wait flag 416, and the reservation is further performed. The identifier of the connection is set in the queue 42 (step 1480).

After the end of step 1480, and
If the reservation waiting flag 416 is a valid value in step 1410, the size of the remaining bandwidth of the transmission path of the connection is determined, and it is determined whether the value of the remaining bandwidth is 0 (step 1430). ). If the value of the remaining bandwidth is 0, the process proceeds to step 1490, where a bandwidth reservation message is transmitted to the previous transfer source (step 149).
0), and the process ends.

If the value of the remaining bandwidth is greater than 0, it is determined whether or not the identifier at the head of the reservation waiting queue 42 is for the connection (step 144).
0). If it is not the connection, a bandwidth reservation message is transmitted to the previous transfer source (step 1450),
The process ends (step 1610). When the identifier of the connection is at the head of the reservation queue 42, the identifier is taken out, and the value of the current remaining bandwidth on the transmission line 3 of the connection and the release waiting bandwidth set in the reservation management table 41 are set. Compare with the value (step 150
0).

When the value of the remaining bandwidth of the transmission path 3 is less than the value of the release waiting band 415, the bandwidth for the remaining bandwidth of the transmission path 3 is additionally secured, and the value of the reserved bandwidth is updated (step). 1510). The value of the requested bandwidth of the bandwidth reservation message is updated to the value of the reserved bandwidth (step 1520), the value of the reservation management table 41 is updated (step 1530), and the bandwidth reservation message is transmitted to the previous transfer source (step 154).
0), the reservation error message is transferred to the next transfer destination (step 1545), and the process ends.

If the value of the remaining bandwidth of the transmission line 3 is equal to or larger than the value of the release waiting band 415 in step 1500, an additional bandwidth corresponding to the value of the release waiting band is secured, and the value of the reserved bandwidth of the bandwidth reservation message is set. Is updated to the value of the requested bandwidth (156).
0), the value of the reservation management table is updated (1580).
At this time, the value of the release waiting band value 416 is set to 0, the reservation flag is set to an invalid value, and the connection identifier is removed from the reservation waiting queue 42, thereby canceling the registration of the band release waiting (1590). Then, a bandwidth reservation message is transmitted to the previous transfer source (1600), and the process ends.

Next, the procedure for transmitting a data packet from the transmitting terminal 1-1 will be described with reference to the flowchart in FIG.

The transmitting terminal 1-2 first determines whether a new bandwidth reservation message has been received (step 2).
010). If not received, it is determined whether or not the registration of the connection of the data to be transmitted exists in the reservation management table 140 (step 2050). If there is no registration, the process ends (step 2040). When the connection has been registered, according to the value of the reserved bandwidth 140-4 set in the reservation management table 140,
The data to be transmitted is transmitted to the data receiving terminal 1-2 (step 2030), and the process ends.

When the reception of the bandwidth reservation message is confirmed in step 2010, the value of the reservation management table 140 is updated based on the content of the bandwidth reservation message (step 2020). Then, the updated reserved band 14
According to the value of 0-4, the data to be transmitted is transmitted to the receiving terminal 1-2 (step 2030), and the process is terminated (step 2040).

Next, the processing procedure of the relay device 2 when receiving the reservation error message will be described with reference to FIG.

When receiving the reservation error message (step 2100), relay device 2 determines whether or not the value of the reserved band set in the reservation error message is 0 (2110). If the value of the reserved bandwidth is 0, the registration of the connection in the reservation management table is deleted (step 2130). If the value of the reserved bandwidth is not 0,
The value of the reserved bandwidth set in the reservation management table is updated (step 2120). Next, the next transfer destination is the receiving terminal 1
-2 is determined (step 2140), and if it is the receiving terminal 1-2, the process is terminated (step 2160). If the next transfer destination is not the receiving terminal 1-2, a reservation error message is transmitted to the relay device 2 of the next transfer destination (step 2150), and the process ends.

The update in step 2120 is for unifying the bandwidth secured by each relay device to the smallest bandwidth secured on the communication path, and enables effective use of the bandwidth. I do. However, a form in which this update is not performed is also possible.

In the communication system, each relay device 2 can independently add a band without receiving a band reservation message.

This is realized by each relay apparatus 2 periodically executing the processing of the flowchart of FIG. 19 in addition to the above processing. Specifically, the relay device 2 monitors the remaining bandwidth of the connection registered in the reservation management table 41 on the transmission line 3 (step 2210), and if the value of the remaining bandwidth is greater than 0, waits for the reservation. The head entry of the queue is taken out (step 2230), and the value of the release waiting band is compared with the value of the remaining band (step 2240).

If the value of the remaining bandwidth is smaller than the value of the bandwidth to be released, a new reservation is made by adding the value of the remaining bandwidth to the value of the reserved bandwidth recorded in the reservation management table 41 for the connection. Band (step 225)
0), the value of the required bandwidth is also set to the value of the reserved bandwidth (step 2).
260). Then, the registration of the reservation management table 41 is updated (step 2270), and a band reservation message and a reservation error message reflecting the updated contents are transmitted (steps 2280, 2290).

If the value of the remaining bandwidth is equal to or greater than the value of the release waiting band at step 2240, the value obtained by adding the value of the release waiting band to the value of the reserved bandwidth recorded in the reservation management table 41 for the connection. Is set as a new reserved band (step 2310), and the registration of the reservation management table 41 is updated (step 2320). Then, the reservation flag is set to an invalid value (step 2330), and a band reservation message reflecting the updated contents is transmitted (step 234).
0).

As described above, by setting each relay device 2 to independently add a band, the band to be reserved can be increased to a desired band in a short period of time. It should be noted that the present method of independently adding a band and the above-described method of adding a band in response to reception of a band reservation message are selectively implemented for each connection according to, for example, a service class. Is also good.

It is also possible to arrange a plurality of reservation waiting queues in the reservation management table and to weight the reading order among the reservation waiting queues according to the service class and the like.

[0076]

As described above, according to the present invention, it is possible to provide a network communication system which flexibly determines a bandwidth to be reserved and establishes a bandwidth reservation in a communication path between terminals in a short time. it can.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a network communication system to which the present invention is applied.

FIG. 2 is a diagram illustrating a configuration of a relay device according to the present invention.

FIG. 3 is a diagram illustrating a configuration of a bandwidth reservation unit of the relay device.

FIG. 4 is a diagram illustrating a configuration of a reservation management table of the relay device.

FIG. 5 is a diagram illustrating a line interface unit.

FIG. 6 is a diagram illustrating a configuration of a terminal according to the present invention.

FIG. 7 is a diagram illustrating a configuration of a band reservation unit of a terminal.

FIG. 8 is a diagram illustrating a configuration of a reservation management table of a terminal.

FIG. 9 shows a format of a message transmitted in the communication system.

FIG. 10 is a diagram illustrating a format of a header part of a message.

FIG. 11 is a diagram illustrating a format of an object part of a message.

FIG. 12 is a sequence diagram (1) used for explaining the bandwidth reservation method according to the present invention.

FIG. 13 is a sequence diagram (2) of the bandwidth reservation method according to the present invention.

FIG. 14 is a flowchart illustrating a processing procedure of a terminal on the data receiving side.

FIG. 15 is a flowchart (1) illustrating a processing procedure of the relay device when receiving the bandwidth reservation message.

FIG. 16 is a flowchart (2) illustrating a processing procedure of the relay device when receiving the bandwidth reservation message.

FIG. 17 is a flowchart illustrating a processing procedure of a terminal on the data transmission side.

FIG. 18 is a flowchart illustrating a processing procedure of the relay device that has received the reservation error message and the terminal on the receiving side.

FIG. 19 is a flowchart illustrating a processing procedure of the relay apparatus for additionally securing a bandwidth.

FIG. 20 is a sequence diagram (1) used for describing a conventional bandwidth reservation method.

FIG. 21 is a sequence diagram (2) used for describing a conventional bandwidth reservation method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 terminal 2 relay apparatus 3 transmission line 41 relay apparatus reservation management table 90 message 91 bandwidth request message 92 bandwidth reservation message 99 data packet 104 terminal reservation management table 901 message header section 902 message object section

Claims (13)

[Claims] An apparatus comprising: a plurality of terminals; one or a plurality of relay devices; and a transmission line connecting the terminals and the relay devices, wherein communication between the terminals is uniquely determined between the terminals.
A network communication system performed through one communication path formed by the transmission line and a relay device, wherein each relay device monitors a free bandwidth of each transmission line, and a first bandwidth. And a message communication means for communicating a message packet for bandwidth reservation, including information specifying a second bandwidth having a value smaller than the first bandwidth, on a communication path between the terminals, In a case where the bandwidth that can be commonly secured in all the connections of the communication path by the communication of the message packet is equal to or larger than the second bandwidth, the first bandwidth is set in each relay device on the communication path. With the upper limit as the upper limit, using a bandwidth securing unit that secures a reservable bandwidth for the connection of the communication path, using a bandwidth that is commonly reserved on the communication path,
A network communication system, comprising: data communication means for communicating data packets. 2. The relay system according to claim 1, wherein said bandwidth securing means further comprises a bandwidth secured for a connection of said communication path smaller than said first bandwidth. A network communication system that additionally secures the free bandwidth with the first bandwidth as an upper limit. 3. The network communication system according to claim 1, wherein the communication of the message packet causes the bandwidth securing unit to further secure a bandwidth secured for the connection of the communication route on the communication route. A network communication system characterized in that the bandwidth is reduced to a specified bandwidth. 4. The network communication system according to claim 3, wherein the communication of the message packet causes the bandwidth securing unit to further increase the bandwidth secured on the communication path by more than the first bandwidth. Is small, and, when a common and newly securable free bandwidth occurs in all connections on the communication path, in each relay device on the communication path, the first bandwidth is set as an upper limit, A network communication system characterized by additionally securing a common and newly securable bandwidth for a connection of the communication path. 5. A communication system comprising: a plurality of terminals; one or a plurality of relay devices; and a transmission line connecting the terminals and the relay devices, wherein communication between the terminals is uniquely determined between the terminals.
A network communication system performed through one communication path formed by the transmission path and a relay device, wherein each relay device has a different value from a unit that monitors an available bandwidth of each transmission line. Message communication means for communicating a message packet for bandwidth reservation, including information for specifying a plurality of predetermined bandwidths, on a communication path between the terminals, by communication of the message packet, all of the communication paths When the bandwidth that can be secured in common in the connection is equal to or greater than the minimum bandwidth among the predetermined bandwidths, in each relay device on the communication path,
Bandwidth securing means for securing the maximum bandwidth that is equal to or less than the bandwidth that can be secured among the plurality of bandwidths for the connection of the communication path, and using the bandwidth commonly secured on the communication path. do it,
A network communication system, comprising: data communication means for communicating data packets. 6. The network communication system according to claim 5, wherein said bandwidth securing means further secures, in each of said relay devices, said free space to secure a larger bandwidth among said plurality of bandwidths. A network communication system characterized by additionally securing a bandwidth for a connection of the communication path. 7. The network communication system according to claim 5, wherein the communication of the message packet causes the bandwidth securing unit to further secure the bandwidth secured for the connection of the communication route in common on the communication route. A network communication system characterized in that the bandwidth is reduced to a specified bandwidth. 8. The network communication system according to claim 7, wherein the communication of the message packet causes the bandwidth securing unit to further increase an available free bandwidth that can be newly secured for all connections on the communication path. When this occurs, in each of the relay devices on the communication path, in order to secure a larger bandwidth among the plurality of bandwidths, the common and newly securable bandwidth is additionally added to the connection of the communication path. A network communication system characterized by securing. 9. A communication system comprising: a plurality of terminals; one or a plurality of relay devices; and a transmission line connecting the terminals and the relay devices, wherein communication between the terminals is uniquely determined between the terminals.
A relay device used in a network communication system performed through one communication path formed by the transmission line and the relay device, wherein: a unit for monitoring an available bandwidth of a connected transmission line; Means for transferring a message packet for bandwidth reservation including information specifying a width and a second bandwidth having a value smaller than the first bandwidth on a communication path between the terminals; On the basis of the content of the message packet, when the bandwidth that can be secured in common in all the connections of the communication path is equal to or larger than the second bandwidth, the first relay device on the communication path Means for securing a reservable bandwidth for the connection of the communication path, with the bandwidth being an upper limit, and data transmitted on the communication path between the terminals using the reserved bandwidth. Means for transferring a data packet. 10. A communication system comprising: a plurality of terminals; one or more relay devices; and a transmission line connecting the terminal and the relay device, wherein communication between the terminals is uniquely determined between the terminals.
A terminal used in a network communication system performed through one communication path formed by the transmission path and the relay device, wherein the terminal has a first bandwidth and a second bandwidth having a value smaller than the first bandwidth. Means for transmitting and receiving a message packet for bandwidth reservation including information designating a bandwidth; and communication of the message packet, for all connections on the communication path, a bandwidth equal to or greater than the second bandwidth. It is characterized by having means for recognizing that the bandwidth has been secured in common and the value of the bandwidth, and means for transmitting and receiving data packets to and from the terminal of the communication partner by using the recognized bandwidth. Terminal to do. 11. A communication system comprising: a plurality of terminals; one or more relay devices; and a transmission line connecting the terminal and the relay device, wherein communication between the terminals is uniquely determined between the terminals.
A bandwidth reservation method used in a network communication system performed through one communication path formed by the transmission path and a relay apparatus, wherein each relay apparatus monitors an available bandwidth of each transmission path, And a message packet for bandwidth reservation including information specifying a bandwidth of the second bandwidth and a second bandwidth having a value smaller than the first bandwidth. When the bandwidth that can be secured in common by all the connections of the communication path is equal to or larger than the second bandwidth, each relay device on the communication path sets the upper limit of the first bandwidth. And reserving a reservable bandwidth for the connection of the communication path. 12. The bandwidth reservation method according to claim 11, wherein the bandwidth secured for the connection of the communication path is smaller than the first bandwidth.
A bandwidth reservation method characterized by additionally securing the free bandwidth with the first bandwidth as an upper limit. 13. The bandwidth reservation method according to claim 11, wherein, by communicating said message packet, a bandwidth secured for each connection of said communication path is increased to a bandwidth secured commonly on said communication path. A bandwidth reservation method characterized by reducing.