JP2006067038A - Communication network, transmission controller, emergency frame processing method to be used for the same and its program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission controller for transmitting an emergency frame by reducing transmission delay, and for reducing the level of influence due to the transmission of the emergency frame. <P>SOLUTION: A transmission frame emergency level detecting part 11 judges the level of emergency from inputted transmission data, and transfers the judged transmission frame to a normal buffer part 13 or an emergency buffer part 15 in the next stage, and notifies a normal control part 14 and an emergency control part 16 of the level of emergency of the transmission frame. When the transmission frame is an emergency frame, the transmission frame emergency level detecting part 11 loads the transmission frame in the transmission queue of the emergency buffer part 15, and acquires the information of current transmission circumstances from the normal control part 14. While a normal frame is being transmitted, and the number of half or less bytes is being transferred, the transmission frame emergency level detecting part 11 abandons the frame which is being transmitted, and transmits the emergency frame by wedging the normal frame. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication network, a transmission control apparatus, and an emergency frame processing method used therefor, and a program thereof, and more particularly to an emergency frame processing method for transmitting an emergency frame such as a failure notification in a communication network such as Ethernet (registered trademark). .

  Conventionally, a frame transmission process in this type of communication network is shown in FIG. In FIG. 5, the emergency frame 202 waits for transmission completion of the normal frame 201 and is transmitted at the timing of the subsequent emergency frame 203.

  Even in the case of an urgent (highest priority) frame, since the frame being transmitted is transmitted after the output is completed, in the conventional frame transmission processing, a transmission waiting time (transmission delay) corresponding to a maximum transmission unit (MTU) ) Occurs.

  When the waiting time in the Ethernet (registered trademark) is estimated, it is as follows. A frame size exceeding the maximum frame size of the Ethernet (registered trademark) standard is called a jumbo frame, but the frame size is not included in the IEEE (Institute of Electrical and Electronic Engineers) standard and varies depending on the vendor.

  For example, when 9000 bytes are transferred at 100 Mbps, the maximum transmission waiting time takes about 720 microseconds. The waiting time is 10 times longer at 10 Mbps and one-tenth as long as 1000 Mbps.

  In order to solve this problem, as a conventional frame transmission processing method, when a special frame is detected, a method of interrupting the processing of the normal frame and preferentially executing the processing of the special frame has been proposed ( For example, see Patent Documents 1 and 2).

  As another conventional frame transmission processing method, when a monitoring frame or unnumbered frame with a high priority is urgently transmitted, even if a long information frame is being transmitted, the transmission of that frame is stopped. A method for immediately transmitting a monitoring frame or an unnumbered frame has been proposed (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 60-80339 JP 61-181238 A JP-A-1-264339

  In the conventional frame transmission processing method described above, even if it is an urgent (highest priority) frame, since the frame being transmitted is transmitted after completion of output, the transmission waiting time (transmission delay) for MTU at the maximum is provided. There is a problem that occurs.

  In Patent Documents 1 and 2 described above, in order to solve this problem, processing of a normal frame is interrupted and priority is given to processing of a special frame. However, since the frame being processed is saved, It may take a lot of time depending on the capacity to be saved.

  Moreover, in the above-mentioned Patent Document 3, in order to solve the above-described problem, a frame being transmitted is immediately discarded and a monitoring frame or an unnumbered frame is immediately transmitted. Since it is performed only by the length of the frame, a long information frame may be discarded even if it is little until the completion of transmission.

  Accordingly, an object of the present invention is to solve the above-described problems, transmit an emergency frame with reduced transmission delay, and reduce the degree of influence due to emergency frame transmission, a transmission control apparatus, and the like It is an object to provide an emergency frame processing method and program for use in the above.

A communication network according to the present invention is a communication network including a transmission control device that performs frame transmission processing,
Detecting means for detecting transmission of at least an emergency frame for notification of failure, and transmitting the emergency frame by discarding a frame currently being transmitted based on a current transmission status when the detection means detects transmission of the emergency frame Determining means for determining whether or not to perform, interrupting the emergency frame when the determining means determines to discard the currently transmitted frame and transmit the emergency frame, and interrupting the emergency frame The transmission control device includes means for retransmitting a frame discarded when it is transmitted after the emergency frame is transmitted.

A transmission control device according to the present invention is a transmission control device that performs transmission processing of a frame,
Detecting means for detecting transmission of at least an emergency frame for notification of failure, and transmitting the emergency frame by discarding a frame currently being transmitted based on a current transmission status when the detection means detects transmission of the emergency frame Determining means for determining whether or not to perform, interrupting the emergency frame when the determining means determines to discard the currently transmitted frame and transmit the emergency frame, and interrupting the emergency frame Means for retransmitting a frame discarded when it is transmitted after transmitting the emergency frame.

  An emergency frame processing method according to the present invention is an emergency frame processing method used in a communication network including a transmission control device that performs frame transmission processing, and detects at least transmission of an emergency frame for failure notification to the transmission control device side. Determining whether to transmit the emergency frame by discarding the frame currently being transmitted based on the current transmission status when transmission of the emergency frame is detected; and Interrupting and transmitting the emergency frame when it is determined to transmit the emergency frame and retransmitting the frame discarded when the emergency frame is interrupted and transmitted after transmitting the emergency frame. I have.

  A program for an emergency frame processing method according to the present invention is a program for an emergency frame processing method used in a communication network including a transmission control device that performs transmission processing of a frame, and at least a failure notification is sent to a computer on the transmission control device side. A process for detecting transmission of an emergency frame; a process for determining whether to discard the currently transmitted frame and transmit the emergency frame based on a current transmission status when transmission of the emergency frame is detected; A process of interrupting and transmitting the emergency frame when it is determined that the currently transmitted frame is discarded and the emergency frame is transmitted, and a frame discarded when the emergency frame is interrupted and transmitted The process of resending later is executed.

  That is, the communication network of the present invention is capable of transmitting an emergency frame such as a failure notification without stopping the transmission state of other frames and waiting for transmission completion mainly in a communication network such as Ethernet (registered trademark). It is characterized by.

  More specifically, in the conventional frame transmission process, when an emergency frame is transmitted during transmission of a normal frame, if the priority control process is in units of transmission frames, the emergency frame is transmitted after the transmission of the normal frame is completed. However, in the communication network of the present invention, the emergency frame is interrupted and transmitted while the normal frame is being transmitted, and then the normal frame is retransmitted. It can be shortened.

  In the communication network of the present invention, when the frame to be transmitted is an emergency frame, transmission such as the current transmission status, that is, whether the frame is being transmitted, whether the frame being transmitted can be discarded, or whether the number of continuous transmissions has not been exceeded Based on the state, it is determined whether to discard the currently transmitted frame and transmit the emergency frame.

  As described above, in the communication network of the present invention, it is possible to discard a frame in the middle of transmission and immediately transmit it depending on the transmission situation, so that an emergency is not required without waiting for the frame in the middle of transmission. The degree of influence due to frame transmission is reduced, and data that is urgently transmitted can be transmitted.

  In this case, in the communication network of the present invention, it is possible to reduce the transmission delay until the transmission is completed by discarding the frame being transmitted and transmitting the frame to be urgently transmitted. When discarding a frame that is being transmitted, in order to reduce the impact of urgent frame transmission, determine whether or not the frame being transmitted is discarded based on the transmission status and the number of continuous transmissions of the urgent frame, and discard the frame being transmitted. The frame is retransmitted after the emergency frame is transmitted.

  With the configuration and operation described below, the present invention can transmit an emergency frame with a reduced transmission delay, and an effect of reducing the degree of influence due to the emergency frame transmission can be obtained.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an emergency frame processing method according to an embodiment of the present invention. In FIG. 1, when the emergency frame 102 is transmitted during transmission of the normal frame 101, the emergency frame 103 is transmitted after the transmission of the normal frame 101 is completed if the priority control process is performed in units of transmission frames.

  In the embodiment of the present invention, the emergency frame 102 is interrupted and transmitted while the normal frame 101 is being transmitted, and then the normal frame 104 is retransmitted. As a result, in the embodiment of the present invention, the waiting time until the emergency frame 102 is transmitted can be shortened.

  If the frame to be transmitted is the emergency frame 102, determine the current transmission status, that is, whether the frame is being transmitted, whether the frame being transmitted can be discarded, and whether the number of continuous transmissions has not been exceeded. The emergency frame 102 is transmitted.

  In this way, according to the embodiment of the present invention, it is possible to discard a frame in the middle of transmission and immediately transmit it according to the transmission status, so that it is possible to immediately transmit without waiting for the frame in the middle of transmission. It is possible to reduce the degree of influence due to urgent frame transmission and transmit data that is urgently transmitted.

  In the embodiment of the present invention, the transmission delay until the transmission is completed can be reduced by discarding the frame being transmitted and transmitting the frame to be transmitted urgently. When discarding a frame that is being transmitted, in order to reduce the impact of urgent frame transmission, it is possible to determine whether or not to discard the frame based on the transmission status and the number of consecutive urgent frame transmissions. The frame is retransmitted after the emergency frame is transmitted.

  FIG. 2 is a block diagram showing the configuration of the transmission control apparatus according to one embodiment of the present invention. In FIG. 2, the transmission control device 1 includes a transmission frame urgency detection unit 11, a retransmission control unit 12, a normal buffer unit 13, a normal control unit 14, an emergency buffer unit 15, an emergency control unit 16, and a transmission selector. 17 and a recording medium 18 for storing a program for realizing the above-described units. The transmission control device 1 is a device for performing the emergency frame processing mainly in a communication network such as Ethernet (registered trademark).

  The transmission frame urgency level detection unit 11 determines the urgency level from the input transmission data, and transfers the determined transmission frame to the normal buffer unit 13 or the emergency buffer unit 15 at the next stage. At that time, the transmission frame urgency detection unit 11 notifies the normal control unit 14 and the emergency control unit 16 of the urgency of the transmission frame.

  When the transmission frame is a normal frame, the transmission frame urgency detection unit 11 loads the transmission frames into the transmission queue of the normal buffer unit 13 based on the input order and transmits the transmission frames through the transmission selector 17.

  When the transmission frame is an emergency frame, the transmission frame urgency detection unit 11 loads the transmission frame into the transmission queue of the emergency buffer unit 15 and obtains information on the current transmission status from the normal control unit 14. When the normal frame is not transmitted, the transmission frame urgency level detection unit 11 suspends the transmission on the normal frame side and transmits the emergency frame.

  The transmission frame urgency level detection unit 11 spends more than half the number of bytes when transmitting a normal frame, and if it is discarded, it spends more time by resending. Send. In this case, a threshold value (transmission ratio) as to whether or not to discard can be set, and when it is set to 0, it is not unconditionally discarded.

  When the number of bytes less than half is being transferred, the transmission frame urgency level detection unit 11 discards the frame being transmitted [specifically, an invalid FCS (Frame Check Sequence) value is added], and the urgent frame is transmitted. Interrupt a normal frame and transmit. The discarded transmission frame is transmitted again by the retransmission control unit 12 after the emergency frame transmission is completed.

  In addition, in order to prevent the normal frame queue from overflowing due to the continuation of emergency frames, this embodiment has a threshold value for limiting the number of continuous transmissions of emergency frames. When the threshold is exceeded, an emergency frame is transmitted after transmitting a normal frame.

  FIG. 3 is a diagram showing an IEEE (Institut of Electrical and Electronic Engineers) 802.3 frame format. In FIG. 3, the IEEE 802.3 frame includes “destination address (6 bytes)”, “source address (6 bytes)”, “type (2 bytes)”, “transmission data (46 to 1500 bytes)”, and “FCS ( 4 bytes) ”.

  In the present embodiment, the “type” area is used to identify the urgent frame, and the urgent frame can be specified by setting the value of the “type” area to a unique value. When connecting to a device not involved in the present embodiment, the type setting is changed via a router.

  FIG. 4 is a flowchart showing the operation of the transmission control apparatus 1 of FIG. The emergency frame transmission operation of the transmission control apparatus 1 according to an embodiment of the present invention will be described with reference to FIGS. The processing shown in FIG. 4 can be realized by the transmission control device 1 [internal CPU (central processing unit) (not shown)] executing the program of the recording medium 18.

  When a transmission frame is input (step S1 in FIG. 4), the transmission control device 1 determines whether the transmission frame is an emergency frame (step S2 in FIG. 4). If it is not an urgent frame, the transmission control device 1 clears the continuous transmission count value N (N is a variable) of the urgent frame (N = 0) (step S3 in FIG. 4), and transmits the frame as a normal frame (step in FIG. 4). S4).

  If it is an urgent frame, the transmission control device 1 determines whether or not the continuous transmission count value N of the urgent frame exceeds a threshold value (initially set value) (step S5 in FIG. 4). When the transmission control device 1 exceeds the threshold value, the continuous transmission count value N is cleared (N = 0) (step S6 in FIG. 4), and one frame transmission is permitted to the normal control unit 13 (step S7 in FIG. 4). Thereafter, it is transmitted as an emergency frame (step S8 in FIG. 4).

  If the threshold value is not exceeded, the transmission control device 1 adds 1 to the continuous transmission count value N (step S9 in FIG. 4), and determines whether a normal frame is being transmitted (step S10 in FIG. 4). When the normal frame is not being transmitted, the transmission control device 1 transmits the emergency frame as it is from the emergency buffer unit 15 (step S11 in FIG. 4).

  If a normal frame is being transmitted, the transmission completion ratio of the frame being transmitted is confirmed (step S12 in FIG. 4), and it is determined whether or not the transmission completion ratio value M (M is an initial set value) has been exceeded (step in FIG. 4). S13). If the transmission completion ratio value M has been exceeded (it is determined not to discard the frame), the transmission control device 1 waits for the completion of transmission of the normal frame (step S14 in FIG. 4) and transmits an emergency frame (step S15 in FIG. 4). .

  When the transmission control device 1 does not exceed the transmission completion ratio value M (determined to discard and transmit the frame), the transmission control device 1 discards the frame being transmitted (adds an invalid FCS) (step S16 in FIG. 4), and the emergency frame Is transmitted (step S17 in FIG. 4). Thereafter, the transmission control device 1 retransmits the discarded normal frame (step 18 in FIG. 4).

  In this way, in this embodiment, the frame in the middle of transmission can be discarded and the emergency frame can be preferentially transmitted, so that the transmission delay of the frame to be transmitted urgently can be reduced.

  In this embodiment, the transmission frame is not simply discarded, but the current transmission status, that is, whether the frame is being transmitted, whether the frame being transmitted can be discarded, and whether the number of continuous transmissions has been exceeded. Since retransmission control is performed after each determination, the influence of emergency frame transmission can be reduced.

It is a figure which shows the emergency frame processing method by embodiment of this invention. It is a block diagram which shows the structure of the transmission control apparatus by one Example of this invention. It is a figure which shows IEEE802.3 frame format. It is a flowchart which shows operation | movement of the transmission control apparatus of FIG. It is a figure which shows the emergency frame processing method by a prior art example.

Explanation of symbols

1 Transmission control device
11 Transmission Frame Urgency Detection Unit
12 Retransmission control unit
13 Normal buffer
14 Normal control unit
15 Emergency buffer
16 Emergency control unit
17 Send selector
18 Recording medium 101, 104 Normal frame 102, 103 Emergency frame

Claims (13)

A communication network including a transmission control device that performs frame transmission processing,
Detecting means for detecting transmission of at least an emergency frame for notification of failure, and transmitting the emergency frame by discarding a frame currently being transmitted based on a current transmission status when the detection means detects transmission of the emergency frame Determining means for determining whether or not to perform, interrupting the emergency frame when the determining means determines to discard the currently transmitted frame and transmit the emergency frame, and interrupting the emergency frame A means for retransmitting a frame discarded when it is transmitted after the emergency frame is transmitted to the transmission control apparatus.   The determination means discards the currently transmitted frame and transmits the emergency frame based on whether the frame is being transmitted, whether the frame being transmitted can be discarded, and whether the number of continuous transmissions has not been exceeded. The communication network according to claim 1, wherein it is determined whether or not to perform.   3. The communication network according to claim 2, wherein the determination unit determines that the frame being transmitted can be discarded when the frame being transmitted is less than a preset transmission completion ratio value.   The normalization frame transmission is permitted when the determination unit determines that the number of continuous transmissions of the emergency frame exceeds a preset threshold, and then the emergency frame transmission is performed. The communication network according to claim 2 or claim 3. A transmission control device that performs frame transmission processing,
Detecting means for detecting transmission of at least an emergency frame for notification of failure, and transmitting the emergency frame by discarding a frame currently being transmitted based on a current transmission status when the detection means detects transmission of the emergency frame Determining means for determining whether or not to perform, interrupting the emergency frame when the determining means determines to discard the currently transmitted frame and transmit the emergency frame, and interrupting the emergency frame And a means for retransmitting a frame discarded when it is transmitted after transmitting the emergency frame.   The determination means discards the currently transmitted frame and transmits the emergency frame based on whether the frame is being transmitted, whether the frame being transmitted can be discarded, and whether the number of continuous transmissions has not been exceeded. 6. The transmission control apparatus according to claim 5, wherein whether or not to perform the determination is determined.   The transmission control apparatus according to claim 6, wherein the determination unit determines that the frame being transmitted can be discarded when the frame being transmitted is less than a preset transmission completion ratio value.   The normalization frame transmission is permitted when the determination unit determines that the number of continuous transmissions of the emergency frame exceeds a preset threshold, and then the emergency frame transmission is performed. The transmission control device according to claim 6 or 7.   An emergency frame processing method used in a communication network including a transmission control device that performs transmission processing of a frame, the step of detecting at least transmission of an emergency frame of a failure notification to the transmission control device side, and transmission of the emergency frame Determining whether to transmit the urgent frame by discarding the currently transmitted frame based on the current transmission status, and discarding the currently transmitted frame and transmitting the urgent frame An emergency frame process comprising: a step of interrupting and transmitting the emergency frame when it is determined to be transmitted; and a step of retransmitting a frame discarded when the emergency frame is interrupted and transmitted after the emergency frame is transmitted Method.   The step of determining whether or not to transmit the urgent frame includes the step of transmitting the frame based on whether the frame is being transmitted, whether the frame being transmitted can be discarded, and whether the number of continuous transmissions has not been exceeded. The emergency frame processing method according to claim 9, wherein it is determined whether or not to transmit the emergency frame by discarding the packet.   The step of determining whether or not to transmit the urgent frame determines that the frame being transmitted can be discarded when the frame being transmitted is less than a preset transmission completion ratio value. The emergency frame processing method described.   11. The normal frame transmission is permitted when it is determined that the number of continuous transmissions of the emergency frame exceeds a preset threshold, and the emergency frame is transmitted thereafter. Item 12. The emergency frame processing method according to Item 11. A program of an emergency frame processing method used in a communication network including a transmission control device that performs transmission processing of a frame, the computer on the transmission control device side detecting at least transmission of an emergency frame of a failure notification, and A process of determining whether or not to transmit the emergency frame by discarding a currently transmitted frame based on a current transmission status when transmission of an emergency frame is detected; and discarding the currently transmitted frame and A program for executing processing for interrupting and transmitting the emergency frame when it is determined to transmit an emergency frame, and processing for retransmitting a frame discarded when interrupting and transmitting the emergency frame after transmission of the emergency frame .

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