JPH01200847A - System for controlling packet transmission - Google Patents

Abstract

PURPOSE:To prevent a data packet to be transmitting from being reception- rejected in a destination communication node by containing the receivable/non- receivable display information of each communication node and transmission reservation information to each communication node in a transmitting right packet. CONSTITUTION:The local area network has plural communication nodes 1-1,..., 1-n connected to a ring-shaped transmission line 2, and addresses A1,..., An for identifying respective communication node in the network are assigned. For the transmission control of the data packet to have user data, a packet 3 for a control to uniquely execute a cycle on the transmission line 2 is used. Each communication node changes the value of a transmission reservation bit corresponding to a destination communication node in the packet 3 from '0' to '1', and the data packet transmission to the designation communication node is reserved. Thus, the transmitting right of the data packet of a communication node group destination in which the data packet transmission is not reserved by the other communication nodes can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention comprises a ring-shaped transmission path and a plurality of communication nodes connected to the transmission path, and data transmission between these communication nodes is performed using data transmission. Regarding data transmission systems using packets, in particular,
Local area network is an example of the data transmission system described above. Nozokerato transmission control is required.

Conventionally, a token passing method has been used as a packet transmission control method in a ring-shaped local area network. In this token passing method, a communication node that captures a unique transmission right packet circulating on a ring-shaped transmission path and erases it from the transmission path is given the right to transmit data packets to any other communication node. Therefore.

When one communication node in the network obtains the right to transmit,
There is a problem in that there is no guarantee that the destination communication node of the data packet is in a state where it can receive the data packet, and the transmitted data packet may be refused reception by the destination communication node.

In order to solve this problem, we incorporated reception permission display information, which indicates whether each communication node in the network is in a state where it can receive data packets, into the transmission right/gate and incorporated it into the transmission right/gate. A packet transmission control method has been proposed in which a communication node is given the right to transmit data packets to a group of communication nodes that are shown to be in a state capable of receiving data packets based on reception permission display information in the transmission right packet. .

[Problem to be Solved by the Invention] The above-mentioned packet transmission control method has a problem in that when multiple communication nodes simultaneously transmit data packets to one communication node, the ring-shaped transmission path becomes swamped in the signal transmission direction. The drawback is that communication nodes near the receiving side communication node can be given priority in transmitting data packets.

Therefore, in an extreme case, a problem arises in that communication nodes that are close to the receiving communication node can continuously transmit data packets, but communication nodes that are far away cannot transmit data packets at all. This means that the buffer for receiving data packets in the receiving communication node changes from being in use to being free.

The receiving side communication node captures the transmission right packet circulating on the transmission path, updates the reception permission display information in the transmission right packet, and indicates that the self communication node is ready to receive the data/Gkerat. Then, when the transmission right packet is sent again to the transmission path, the communication node near the receiving communication node along the signal transmission direction of the transmission path will receive the transmission right first.・This is due to the fact that it is possible to capture Gukerato and obtain the right to transmit Data Noquette.

[Means to solve the problem]

According to the invention.

In a data transmission system that includes a ring-shaped transmission path and a plurality of communication nodes connected to the transmission path, and performs data transmission between nine communication nodes using a data network.

For A' ticket transmission control of data packets.

In addition to the reception availability display information for each communication node indicating whether or not the communication node is in a state where it can receive data packets, it also indicates whether or not each communication node is reserved for transmitting data packets addressed to that communication node. A control node is used that includes transmission reservation information indicating the transmission schedule and is uniquely circulated on the transmission path.

A means for writing reception permission display information for the self-communication node into the control packet that each communication node has circulated nine times, and a means for writing the reception permission display information for the self-communication node into the control packet that has been circulated nine times, and a means for writing the control packet within a thousand kerats that has been circulated to reserve the transmission of data packets addressed to other communication nodes. means for updating transmission reservation information; and means for receiving nine control packets, erasing them from the transmission path, and then transmitting nine data packets.

After transmitting the data packet, the transmitter has means for transmitting the previously received control signal to the transmission path again after updating the reception permission display information for the destination communication node of the data packet.

The condition that the communication node that has taken in the control packet indicates that it is in a state where it can receive the data by the reception permission display information in the control packet, and the transmission in the control packet. Data addressed to a group of communication nodes that satisfies the condition that the reservation information indicates that no communication node other than the communication node that captured the control packet has reserved the transmission of data to the control packet. - A packet transmission control method is obtained, which is characterized in that the right to transmit packets is granted.

〔Example〕

Next, nine embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an overall diagram of a local area network which is a data transmission system using the packet transmission control method of the present invention. In the figure, this local area network has a plurality of (n) connected to a ring-shaped transmission line 2.
Communication node 1-1゜1-2.1-3. ..., 1-n
have. Also, 9 communication nodes 1-1. ..., 1-
Addresses AI, . . . , An for uniquely identifying each communication node within the network are assigned to n. In this embodiment, in order to control the transmission of data packets containing user data, the number of free reception buffers of each communication node and transmission reservation information for each communication node are provided.

Only one control packet 3 circulating on the transmission path 2 is used.

The type of kerato for this control is shown in Figure 2. In the figure, the control packet stores a start flag section that indicates the start of a packet and indicates that this packet is a control packet, and the number of free reception packets of each communication node in the network. a storage unit for the number of free reception buffers; a transmission reservation information storage unit for storing transmission reservation information consisting of transmission reservation bits for reserving transmission to each communication node in the network; and a termination flag indicating the end of the mother packet. It consists of two parts.

Each communication node changes the value of the transmission reservation bit corresponding to the destination communication node in this control e-ket from “0” to “1”.
, to reserve data transmission to the destination communication node. A communication node takes in this control signal circulating on the ring-shaped transmission path 2 and erases it from the transmission path 2.

The number of free reception buffers stored in the free reception buffer storage section of the captured control packet is not "0", and the transmission reservation bit of the transmission reservation information storage section of the control packet is set to "1" by another communication node. ``'', that is, the right to transmit data packets addressed to a group of communication nodes for which data packet transmission is not reserved by another communication node is obtained.

The format of the data section in this network is shown in FIG. In the figure, a data packet includes a start flag section that indicates the start of the packet and indicates that this packet is a data packet, a destination address section that stores the address of the destination communication node of the data section, and a destination address section that stores the address of the destination communication node of the data packet. It consists of a sender address section that stores the address of the sender communication node, a data section that stores the data to be transferred, and a termination flag section that indicates the end of the transfer.

Figure 4 shows 1. FIG. 3 is a diagram showing the internal configuration of each communication node.

In the figure, one communication node 1 has a network interface section 11 having a packet transmission/reception function, and a data processing section 12 that processes transmitted and received data packets. The network interface section 11 includes a transmission/reception control section 111 that controls transmission of packets onto the transmission path 2 and reception of packets from the transmission path 2, and a transmission buffer 112 for storing data packets to be transmitted.

Two receive buffers for storing received data packets, namely receive buffer 113 and receive buffer 1
14. It has a function of processing the received data stored in the data section of the data packet stored in the data processing unit 113 or the reception buffer 114. When the data processing unit 12 completes the reception data processing, the reception buffer becomes empty and the 9th data node
It becomes possible to store containers.

Transmission reservation flag 1 for storing that a communication node has reserved transmission of data packets addressed to other communication nodes
112. The transmission/reception control unit 111 always
The signal on the transmission path 2 is examined to detect a knockout, and the following operations are performed depending on the type and content of the detected knockout and the state of the own communication node at the time of detection.

First, the operation of the transmission/reception control section 111 when a control packet is detected will be described.

First, the transmission/reception control unit 111 compares the number of free reception buffers of the own communication node stored in the detected control packet with the actual number of free communication buffers, and if they do not match, the number of free reception buffers of the self communication node stored in the detected control packet is The number is stored in the control packet. Subsequently, the transmission/reception control unit 111 checks whether or not the data to be transmitted is stored in the transmission buffer 112, and if it is not stored, the transmission/reception control unit 111 transfers the detected control packet onto the transmission path 2. Send to. When a data packet to be transmitted is stored in the transmission buffer 112, the transmission/reception control unit 111 determines the number of free reception buffers stored in the detected control A' packet and the number of transmission buffers stored in the detected control A' packet for the destination communication node of the data packet. reservation bits and performs the next operation based on their values and the value of transmit reservation 7 lag 1112.

The number of free receive buffers at the destination communication node is "0".

If the transmission/reservation bit to the destination communication node is "1", the transmission/reception control unit 111 only transmits the detected control packet onto the transmission path 2.

The number of free receive buffers at the destination communication node is "0".

If the transmission reservation bit to the destination communication node is '0', the transmission/reception control unit 111 changes the transmission reservation bit in the crawl control node 9 bit to 1'', thereby transmitting the data packet to the destination communication node. Reserve A for its control.
'Send on ticket transmission path 2. At the same time, the value of the transmission reservation flag 1112 is set to "1".

The number of free receive buffers of the destination communication node is not "0",
And when the transmission reservation bit to the destination communication node is 1" and the transmission reservation flag 1112 is '0".

That is, if the destination communication node is in a data packet receivable state but data packet transmission is reserved by another communication node, the transmission/reception control unit 111 transmits the detected control packet onto the transmission path 2. Only.

The number of free receive buffers of the destination communication node is not “0#”
When the transmission reservation bit to the destination communication node is 1'' and the transmission reservation flag 1112 is 1''.

Or, the number of free reception buffers of the destination communication node is not ``0'' and the transmission reservation bit to the destination communication node is ``0''.
In other words, if the destination communication node is ready to receive data packets, either the own communication node has reserved data transmission to the destination communication node, or no communication node is ready to send data packets to the destination communication node. If no reservation has been made, the transmission/reception control unit 111 stores the detected control packet in the control packet storage unit 1111,
After erasing from the transmission path 2, the data packet in the transmission buffer 112 is transmitted onto the transmission path 2. After the transmission is completed, the transmission/reception control unit 111 subtracts the number of free reception buffers of the destination communication node of the control packet in the control packet storage unit 1111 by 1, and if the transmission reservation bit to the destination communication node is “1”, then It is changed to "0" and transmitted over transmission path 2 again. Further, if the transmission reserved flag 1112 is "1', it is changed to 0".

Second, the operation of the transmission/reception control section 111 when a data packet is detected will be described.

The transmission/reception control unit 111 compares the content of the destination address field of the detected data packet with the address of its own communication node, and if they match, receives the detected data packet and sends it to the reception Buffer 114
It is stored in the vacant one of the two, and is deleted from the transmission path 2. The 9-packet transmission control system guarantees that at least one of the two receive buffers is empty. Also, if the contents of the destination address field and the address of the self-communication node do not match.

The transmission/reception control unit 111 allows the detected data packet to pass through as is, and transmits it onto the transmission path 2 .

The data transmission/reception operation in this embodiment is explained in the fifth section.
This will be explained with reference to FIGS. 2 and 3.

A case will be described in which communication node 1-19, communication node 1-2I, and communication node 1-3 in FIG. 5 each transmit one data packet to communication node 1-4.

Initially, it is assumed that only one of the two reception buffers of the 9 communication nodes 1-4 is in an empty state, and the empty reception buffer of the communication nodes 1-4 in the control buffer circulating on the transmission path 2 and the communication node 1-4 in the kerato. The number is "1" and the transmission reservation bit for communication nodes 1-4 is 01.

It is assumed that the control device is located between communication nodes 1-1 and 1-2. The explanation will be given below according to the numbers in FIG.

i) First, one communication node 1-2 takes in the nine control devices 31 that have been circulating on the transmission path 2 and erases them from the transmission path 2. Communication node 1-12, which obtained the transmission right in this way,
After transmitting the data packet 32 to the communication node 1-4, the control packet 33 with the number of empty reception buffers of the communication node 1-4 changed to "0#" is transmitted onto the transmission line 2.

1j) Next, 9 communication nodes 1-3 are used for control. ket 3
3 is detected, but its control No.J? Since the number of free reception buffers of the communication node 1-4 in the packet 33 is "0", the transmission right cannot be obtained, and the transmission reservation bit for the communication node 1-4 in the control mother packet 33 is set to "0". 0" to "1"
The control packet 34 changed to `` is transmitted on the transmission path 2. In this way, the 9 communication nodes 1-3 are transferred to the 9 communication nodes 1-4.
Reserve data/gukerato transmission to.

111) Next, 9 communication node 1-1 detects the control Yakerato 34, but 9 communication node 1-1 detects 9 communication node 1.
Since the number of free reception buffers for -4 is 0'' and the transmission reservation bit is already 1, it is not possible to obtain the transmission right or make a transmission reservation, and the detected control packet 34 is sent directly to the transmission path 2. The transmitted control gear 34 continues to circulate on the transmission path 2.

1 Eventually, when the processing of the received data packet is completed at the 9 communication node 1-4 and one of the reception buffers becomes empty, the 9 communication node 1-4 transfers the circulating control packet 3.
Control packet 3 that captured 4 and changed the number of free reception buffers of its own communication node from "0" to "1".
5 on transmission path 2.

■) Next, the 9 communication node 1-1 sends its control packet 3
5 is detected, but since the transmission reservation bit for communication node 1-4 in the control/9 bit is already 1", communication node 1-4 cannot obtain the transmission right or make a transmission reservation. Unable to do so, the control node 35 is transmitted directly onto the transmission line 2.

(1) After that, one communication node 1-3 detects the control packet 35. Since the number of free reception buffers of the communication node 1-4 in the control Δkerat 35 is not O, and the self-communication node has reserved the data transmission addressed to the communication node 1-4, 9 communication nodes 1-3 is control packet 3
5, deletes it from the transmission path 2, and obtains the right to transmit to the communication node 1-4 of the Send Kerato 36 to communication node 1-4, and after sending, change the number of free reception buffers of communication node l-4 to 0'', and
Control packet 3 with destination transmission reservation bit changed to 0''
7 on transmission line 2.

This means that the data packet transmission of the 9 communication nodes 1-2 and 1-3 has been completed. Next, communication node 1-1 can make a transmission reservation for communication node 1-4. Each time the communication node 1-4 completes the processing of the received data packet, it updates the number of free reception buffers of its own communication node in the control network that it has circulated.

In this way, the right to transmit to a certain communication node in the network moves in order along the signal transmission direction on the transmission path.

In this embodiment, the number of transmission buffers that one communication node has is 1. The number of reception buffers was set to 2.

Networks with different numbers of buffers can also be constructed.

〔Effect of the invention〕

As explained above, in the present invention, by including reception permission display information of each communication node and transmission reservation information to each communication node in the transmission right/guage.

This has the advantage that it is possible to realize a data transmission system in which transmitted data packets are not rejected by the destination communication node, and all communication nodes are given the right to transmit at the same time.

[Brief explanation of the drawing]

FIG. 1 is an overall diagram of a data transmission system to which a packet transmission control method according to an embodiment of the present invention is applied; FIG. 2 is an explanatory diagram of the control packet format used in the data transmission system of FIG. 1; Figure 3 is an explanatory diagram of the data/seven packet format used in the data transmission system in Figure 1, Figure 4 is a block diagram of the communication node in Figure 1, and Figure 5 is an illustration of the data in the data transmission system in Figure 1. FIG. 3 is a diagram showing an example of a packet transmission operation. 1 = 1-1.1-2.1-3, 1-4, 1-n
. . . Communication node, 11 . . . Network interface section, 111 . . . Transmission/reception control section, 1111 . . . 113,114...
- Receive buffer. 12...Data processing unit, 3, 31, 33, 34°35
．． 37... Control packet l-, 32, 36... Seven data packets. Figure 1 Figure 4

Claims (1)

[Claims] 1. A data transmission system comprising a ring-shaped transmission path and a plurality of communication nodes connected to the transmission path, and in which data transmission between the communication nodes is performed using data packets, comprising: For packet transmission control, for each communication node, reception permission display information indicating whether or not the communication node is in a state where it can receive the data packet, and for each communication node, the data addressed to the communication node. Using a control packet which includes transmission reservation information indicating whether packet transmission is reserved or not and which circulates uniquely on the transmission path, each of the communication nodes sends information about the self-communication node to the control packet which has circulated. means for writing the reception permission display information of the communication node; means for updating the transmission reservation information in the control packet that has circulated to reserve the transmission of the data packet addressed to another communication node; means for capturing a control packet and erasing it from the transmission path, and then transmitting the data packet; and after transmitting the data packet, transmitting the previously captured control packet to a destination communication node of the data packet in the control packet; After updating the reception availability display information for
and means for transmitting data to the transmission path again, the communication node having taken in the control packet is shown to be in a state capable of receiving the data packet by the reception availability display information in the control packet. and a condition that the transmission reservation information in the control packet indicates that no communication node other than the communication node that has captured the control packet has reserved data packet transmission. 1. A packet transmission control system, wherein a right to transmit the data packet addressed to the communication node group that satisfies both of the above is granted.