JP2005159792A - Communication system and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system for suppressing occurrence of delay and fluctuation by interrupting transmission of non-preferential frames and earlier transmitting preferential frames wherein real time performance is required when the preferential frames arrive during transmission of the non-preferential frames. <P>SOLUTION: The communication system wherein transferred preferential frames and non-preferential frames are separately stored to a preferential buffer and a non-preferential buffer and the preferential frames stored in the preferential buffer are preferentially transmitted to a network, is provided with a fragment processing means that interrupts the transmission of the non-preferential frames and transmits the arrived preferential frames when the preferential frames arrive during the transmission of the non-preferential frames stored in the non-preferential buffer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication system and a communication method for transmitting a priority frame that requires real-time performance and a non-priority frame that allows some delay.

While communication systems that connect networks to each other are being developed, for example, VoIP (Voice over Internet Protocol) and other real-time characteristics are required, and data that is weak to delay and fluctuations, and WEB that allows some delay, etc. There is a demand for a communication system that realizes communication that does not impair the real-time property even if the data of the above exists.

  Next, the configuration of a communication system according to the prior art will be described. FIG. 8 shows a configuration example of a conventional communication system. In FIG. 8, the communication system includes a line connection device 1, a priority buffer 1A, a non-priority buffer 1B, and a line connection device 3.

The line connection device 1 is connected to a network 10 such as Ethernet (registered trademark). Data input from the network 10 to the line connection apparatus 1 is required to have real-time characteristics such as VoIP and is vulnerable to delay and fluctuation. Therefore, priority data to be preferentially transmitted to the network 20 and data such as WEB, that is, somewhat It consists of non-priority data that can be tolerated.

As for data from the network 10, a setting value corresponding to the priority is predetermined for each bit in the frame. The line connection apparatus 1 can give priority to the input frame by identifying the set value. Data frames are stored in the priority buffer 1A and the non-priority buffer 1B according to the priority.

  The line connection device 3 is connected to a second network 20 such as a WAN (Wide Area Network). Further, the line connection device 3 monitors the priority buffer 1A and the non-priority buffer 1B, respectively, sends out a frame from the priority buffer 1A when there is a frame in the priority buffer 1A, and non-priority buffer when there is no frame in the priority buffer 1A. A frame is transmitted from 1B.

Next, the operation of the communication system configured as shown in FIG. 8 will be described with reference to FIG. FIG. 9 shows an example in which frames are accumulated from the network 10 in the priority buffer 1A and the non-priority buffer 1B and sent to the network 20 via the line connection device 3.

In FIG. 9, non-priority frames are first stored in the non-priority buffer 1B from the network 10 to the line connection device 1. At this time, the line connection device 3 attaches the head identification marking code C1 to the non-priority frame and starts transmission. Frames are sent in the direction of the arrow in FIG.

On the way, the priority frame is accumulated in the priority buffer 1A. At this time, the non-priority frame is still being transmitted, and when the transmission of the non-priority frame is completed, the end identification marking code C0 is added to complete the transmission. Subsequently, the priority frame is transmitted with the head identification marking code C1. At the end of transmission of the priority frame, an end identification marking code C0 is added, and transmission to the network 20 is completed.

  In the communication system as shown in FIGS. 8 and 9, only one of the priority frame and the non-priority frame is continuously transmitted to the network 20, and the transmission of the other frame may be in a depleted state. In order to solve this problem, as described in Patent Document 1, there is known means for switching between sending priority frames and non-priority frames at regular intervals when sending priority frames and non-priority frames. No mention is made of problems in the state of the invention.

Japanese Patent No. 3457636

In the configuration of FIG. 8, as shown in FIG. 9, once transmission of frames from the buffer is started, there is no interruption until the extraction of one frame is completed. Therefore, for example, when the non-priority frame from the network 10 is long, even if the priority frame is accumulated during the transmission, the transmission of the priority frame is awaited until the transmission of the non-priority frame is completed.
In particular, when the bandwidth of the network 20 is narrow, the priority frame transmission waiting time becomes long. For example, when the priority frame to be transmitted is an application such as VoIP, problems such as delay and fluctuation occur.

  In the present invention, when a priority frame arrives during transmission of a non-priority frame, the transmission of the non-priority frame is interrupted, and a priority frame requiring real-time performance is transmitted first, thereby suppressing delay and fluctuation. The purpose is to provide a system.

  In order to achieve such a problem, the invention according to claim 1 is arranged to store the transferred priority frames and non-priority frames in a priority buffer and a non-priority buffer, and store the priority frames stored in the priority buffer. In a communication system that preferentially sends frames to the network, when a priority frame arrives during transmission of non-priority frames stored in the non-priority buffer, transmission of the non-priority frame is interrupted and the priority frame arrived A fragment processing means for performing transmission is provided.

  According to a second aspect of the present invention, in the communication device according to the first aspect, the fragment processing means resumes the transmission of the interrupted non-priority frame after completion of the transmission of the priority frame.

  According to a third aspect of the present invention, there is provided a communication system in which the transferred priority frames and non-priority frames are sorted and stored in a priority buffer and non-priority buffer, and are sent to the network preferentially from the priority frames stored in the priority buffer. When the priority frame arrives while sending the non-priority frame stored in the non-priority buffer, the remaining amount of the non-priority frame that has not been sent is compared with the prescribed value, and the remaining amount is larger than the prescribed value. When the remaining priority frame is less than the specified value, the transmission of the non-priority frame is interrupted, and when the remaining amount is smaller than the specified value, the transmission of the priority frame is started after the non-priority frame transmission is completed. A processing means is provided.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, when a priority frame arrives during transmission of the non-priority frame stored in the non-priority buffer, the remaining amount of the non-priority frame that has not been transmitted is confirmed. Non-priority frame monitoring means is provided.

  According to a fifth aspect of the present invention, in the first to fourth aspects of the invention, the fragment processing means generates a marking code by combining a head identification marking code and an end identification marking code assigned to the head and tail of a frame. The marking code is added to the non-priority frame as an interruption start code and an interruption end code.

  According to a sixth aspect of the present invention, there is provided a communication method in which the transferred priority frames and non-priority frames are sorted and stored in a priority buffer and a non-priority buffer, and the priority frames stored in the priority buffer are preferentially transmitted to the network. When the priority frame arrives while the non-priority frame stored in the non-priority buffer is being transmitted, transmission of the non-priority frame is interrupted and the arrived priority frame is transmitted.

  According to a seventh aspect of the present invention, in the communication device according to the sixth aspect, after the completion of the transmission of the priority frame, the transmission of the interrupted non-priority frame is resumed.

  The invention according to claim 8 is a communication method in which the transferred priority frame and non-priority frame are distributed and stored in a priority buffer and non-priority buffer, and are sent to the network preferentially from the priority frames stored in the priority buffer. When the priority frame arrives while sending the non-priority frame stored in the non-priority buffer, the remaining amount of the non-priority frame that has not been sent is compared with the prescribed value, and the remaining amount is larger than the prescribed value. If the remaining priority is less than the specified value, stop sending the non-priority frame and start sending the priority frame after completing the sending of the non-priority frame. It is characterized by.

  According to a ninth aspect of the present invention, in the communication method according to the sixth to eighth aspects, the marking code is generated by combining the head identification marking code and the end identification marking code given to the head and tail of the frame, and this marking is generated. Codes are assigned to non-priority frames as interruption start codes and interruption end codes.

According to the present invention, when priority frames are stored in the priority buffer during non-priority frame transmission, fragment processing for interrupting transmission of non-priority frames is performed and priority frames are transmitted first. There is no waiting. Therefore, communication without delay and fluctuation in the output side network is possible.

Also, the number of non-priority frames that have not been sent when priority frames are stored in the priority buffer is monitored, and when the remaining number of unsent frames is large, fragment processing that interrupts the sending of non-priority frames is executed. When the number is low, the execution of the fragment processing is controlled so that the non-priority frame is transmitted first without executing the fragment processing. Thereby, a priority frame and a non-priority frame can be transmitted more efficiently.

  The communication system according to the present invention will be described below. FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, the same components as those described above are given the same reference numerals. In the embodiment of FIG. 1, a line connection device 2 and fragment processing means 2A are provided.

The line connection device 2 connected to the network 20 monitors the priority buffer 1A and the non-priority buffer 1B, respectively. When there is a frame in the priority buffer 1A, the frame is sent from the priority buffer 1A, and there is no frame in the priority buffer 1A. When a frame is sent from the non-priority buffer 1B.

The line connection device 2 includes the fragment control means 2A. When the priority frame is accumulated in the priority buffer 1A during transmission of the non-priority frame accumulated in the non-priority buffer 1B, the fragment control means 2A performs the fragment processing. The transmission of the non-priority frame is interrupted, the transmission of the priority frame is started, and the transmission of the non-priority frame is resumed after the completion of the priority frame transmission.

  Next, the operation of the communication system configured as shown in FIG. 1 will be described with reference to FIG. FIG. 2 shows an example in which frames are accumulated from the network 10 in the priority buffer 1 </ b> A and the non-priority buffer 1 </ b> B and sent to the network 20 via the line connection device 2.

In FIG. 2, a non-priority frame is first stored in the non-priority buffer 1B from the network 10 to the line connection device 1. At this time, the line connection device 2 attaches the head identification marking code C1 to the non-priority frame and starts transmission. Frames are sent in the direction of the arrow in FIG.

On the way, the priority frame is accumulated in the priority buffer 1A. At this time, the fragment control means 2A adds fragment start codes C1 and C0 to interrupt transmission of the non-priority frame, adds a head identification code C1 to the priority frame, and starts transmission of the priority frame. At the end of transmission, an end identification marking code C0 is assigned to complete transmission.

Fragment end codes C1 and C0 are added to the head of the non-priority frame waiting to be transmitted after confirming this, and the frame transmission is resumed. At the end of non-priority frame transmission, the end identification marking code C0 is added Thus, transmission to the network 20 is completed.

FIG. 3 is an operation flowchart of the embodiment of FIG. Hereinafter, the operation will be described in the order of steps.
In step A1, the presence or absence of a priority frame is determined.
If there is no priority frame in step A1, it is determined in step A2 whether fragment processing is being executed. If there is a priority frame, the priority frame is transmitted in step A7.
If the fragment processing is not executed in step A2, the presence / absence of a non-priority frame is determined in step A3. If the fragment processing is executed, the priority frame is transmitted in step A8.
If there is a non-priority frame in step A3, the non-priority frame is transmitted in step A4. If not, the process returns to step A1 to repeat the process.
In step A5, the presence / absence of a priority frame is determined.
If there is a priority frame in step A5, fragment processing is executed in step A6, and transmission of the priority frame is started in step A7. If there is no priority frame, it is determined in step A9 whether transmission of the non-priority frame is completed.
If the transmission of the non-priority frame is not completed in step A9, the transmission of the non-priority frame is continued in step A4. If the transmission is completed, the process returns to step A1 and the process is repeated.

With the above processing, when priority frames are stored in the priority buffer during transmission of non-priority frames, fragment processing for interrupting transmission of non-priority frames is performed, and priority frames are transmitted without waiting.

    Next, another embodiment of the communication system according to the present invention will be described. FIG. 4 is a block diagram showing another embodiment of the present invention. In this embodiment, a non-priority frame monitoring means 4 and a line connection device 5 are provided. The line connection device 5 includes fragment processing means 5A. The line connection device 5 is connected to the network 20 similarly to the line connection device 3 of FIG.

  4, the data from the network 10 stores data frames in the priority buffer 1A and the non-priority buffer 1B according to the priority, as in FIG.

The non-priority frame monitoring means 4 monitors the transmission frame amount of the non-priority frame or the remaining amount of unsent frames.

When the priority frame is stored in the priority buffer 1A, the line connection device 5 confirms the data of the non-priority frame monitoring means 4 and sets the remaining amount of the non-priority frame that has not been transmitted in advance to a specified value. Compare with. When the remaining number of non-transmitted frames in the non-priority frame is larger than a specified value, fragment processing is performed to interrupt the transmission of the non-priority frame and the arrived priority frame is transmitted. When the remaining amount is smaller than the specified value, the fragment processing is not performed and the sending of the priority frame is started after the sending of the non-priority frame is completed.

The specified value is set so as not to affect the priority frame traffic within the range allowed by the user, for example, according to the speed of the network 20.

  Next, the operation of the communication system configured as shown in FIG. 4 will be described with reference to FIGS. FIG. 5 shows an example of frame transmission when the remaining amount of untransmitted frames is larger than a preset specified value. Frames are sent in the direction of the arrow in FIG.

In FIG. 5, a non-priority frame is first stored in the non-priority buffer 1B from the network 10 to the line connection device 1. At this time, the line connection device 5 attaches the head identification marking code C1 to the non-priority frame and starts transmission.

On the way, the priority frame is accumulated in the priority buffer 1A. At this time, the fragment control means 5A of the line connection device 5 compares the number of unsent frames in the non-priority buffer 1B from the non-priority frame monitoring means 4 with a specified value. If it is determined that the remaining amount of unsent frames exceeds a preset value, fragment start codes C1 and C0 are assigned to the non-priority frames to interrupt the sending of the non-priority frames, and the leading identification code C1 is assigned to the priority frames. To start sending the priority frame, and at the end of sending the priority frame, the end identification marking code C0 is given to complete the sending.

The fragment end code C1C0 is added to the head of the non-priority frame transmission waiting frame which has been interrupted after confirming this, and the transmission of the non-priority frame is resumed. At the end of transmission of the non-priority frame, the end identification marking code C0 is added to complete transmission to the network 20.

FIG. 6 shows an example of frame transmission when the remaining amount of untransmitted frames is less than a predetermined value set in advance. Frames are sent in the direction of the arrow in FIG.

In FIG. 6, a non-priority frame is first stored in the non-priority buffer 1B from the network 10 to the line connection device 1. At this time, the line connection device 5 attaches the head identification marking code C1 to the non-priority frame and starts transmission.

On the way, the priority frame is accumulated in the priority buffer 1A. At this time, the fragment control means 5A of the line connection device 5 compares the number of unsent frames in the non-priority buffer 1B from the non-priority frame monitoring means 4 with a prescribed value, and a prescribed value in which the remaining amount of unsent frames is set in advance. Judge that it is less.

At this time, the fragment processing is not executed for the non-priority frame, and the end identification marking code C0 is added at the end of transmission of the non-priority frame to complete the transmission. After confirming this, the head identification code C1 is added to the priority frame and transmission of the priority frame is started. When the transmission of the priority frame is completed, the end identification marking code C0 is added and transmission to the network 20 is completed.

FIG. 7 is an operation flowchart of the embodiment shown in FIG. Note that the description of the same operation as in FIG. 3 is omitted.
Steps B1 to B4 are the same as steps A1 to A4 in FIG. In step B5, the presence / absence of a priority frame is determined.

If there is a priority frame in step B5, in step B6, the remaining number of untransmitted frames detected by the non-priority frame monitoring means is compared with a preset specified value. If there is no priority frame, it is confirmed in step 10 whether or not transmission of a non-priority frame has been completed.

If the remaining number of untransmitted frames is larger than the specified value in step B6, fragment processing is executed in step B7, and priority frame transmission is started in step B8. If the remaining number of unsent frames is smaller than the specified value, fragment processing is not executed, all non-priority frames are sent in step B11, and then the process returns to step B1 to send priority frames.

With the above processing, when priority frames are stored in the priority buffer during transmission of non-priority frames, fragment processing for interrupting transmission of non-priority frames is performed, and priority frames are transmitted without waiting.

In FIG. 4, the non-priority frame monitoring unit 4 is configured separately, but may be configured to function integrally with the line connection device 5 or the fragment control unit 5A. Further, in this description, the non-priority frame monitoring means has shown an example of monitoring the remaining number of non-sending frames of non-priority frames, but the number of sending frames may be monitored and a value to be compared with a specified value may be obtained by calculation. .

It is a block diagram of one Example of this invention. It is operation | movement explanatory drawing of the Example of FIG. It is an operation | movement flowchart of the Example of FIG. It is a block diagram which shows the other Example of this invention. It is operation | movement explanatory drawing of the Example of FIG. It is operation | movement explanatory drawing of the Example of FIG. 5 is an operation flowchart of the embodiment of FIG. It is the figure which showed the structural example of the communication system by a prior art. It is operation | movement explanatory drawing of the prior art example of FIG.

Explanation of symbols

1, 2, 5 Line connection device 1A Priority buffer 1B Non-priority buffer 2A Fragment processing means 4 Non-priority frame monitoring means 5A Fragment processing means 10 Network 20 Network

Claims (9)

In a communication system that distributes and stores transferred priority frames and non-priority frames in priority buffers and non-priority buffers, and sends them to the network preferentially from the priority frames stored in the priority buffers.
When a priority frame arrives while sending a non-priority frame stored in the non-priority buffer, it comprises fragment processing means for interrupting the sending of the non-priority frame and sending the reached priority frame. Communication system.   2. The communication system according to claim 1, wherein the fragment processing unit resumes transmission of the interrupted non-priority frame after completion of transmission of the priority frame. In a communication system that distributes and stores transferred priority frames and non-priority frames in priority buffers and non-priority buffers, and sends them to the network preferentially from the priority frames stored in the priority buffers.
When the priority frame arrives while sending the non-priority frame stored in the non-priority buffer, the remaining amount of the non-priority frame that has not been sent is compared with the specified value, and the remaining amount is larger than the specified value Performs the sending of the reached priority frame by interrupting the sending of the non-priority frame, and when the remaining amount is smaller than the specified value, the fragment processing for starting the sending of the priority frame after completing the sending of the non-priority frame A communication system comprising means.   Non-priority frame monitoring means is provided for checking the remaining amount of non-priority frames that have not been sent when a priority frame arrives while sending non-priority frames stored in the non-priority buffer. The communication system according to claim 3.   The fragment processing means generates a marking code by combining a head identification marking code and an end identification marking code assigned to the head and tail of the frame, and uses the marking code as a break start code and a break end code in a non-priority frame. The communication system according to claim 1, wherein the communication system is assigned. In the communication method in which the priority frame and the non-priority frame that have been transferred are distributed and stored in the priority buffer and the non-priority buffer, and the priority frame stored in the priority buffer is preferentially transmitted to the network.
A communication method, wherein when a priority frame arrives during transmission of a non-priority frame stored in the non-priority buffer, transmission of the non-priority frame is interrupted and the arrived priority frame is transmitted.   The communication method according to claim 6, wherein the transmission of the interrupted non-priority frame is resumed after the transmission of the priority frame is completed. In the communication method in which the priority frame and the non-priority frame that have been transferred are distributed and stored in the priority buffer and the non-priority buffer, and the priority frame stored in the priority buffer is preferentially transmitted to the network.
When the priority frame arrives while sending the non-priority frame stored in the non-priority buffer, the remaining amount of the non-priority frame that has not been sent is compared with the specified value, and the remaining amount is larger than the specified value The transmission of the non-priority frame is interrupted and the arrived priority frame is transmitted. When the remaining amount is smaller than the specified value, the transmission of the priority frame is started after the transmission of the non-priority frame is completed. A characteristic communication method. A marking code is generated by combining a head identification marking code and an end identification marking code given at the head and tail of a frame, and the marking code is given to a non-priority frame as a break start code and a break end code. The communication method according to any one of claims 6 to 8.

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