JPH06112957A - Network system - Google Patents

Abstract

PURPOSE:To provide a network system not losing the urgency without need of awaiting the data transmission when the transmission of urgent data is required in the network system of the token bus system. CONSTITUTION:This network of the token bus system is featured to make transmission and reception of urgent data and to be provided with an emergent data transmission means sending urgent data to the network as required, a token bus protocol control section 1 controlling the communication, an urgent data detection section 2 detecting urgent data in a network line, and a collision detection section 3 monitoring a data flow and collision in the network line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a token bus system network system.

[0002]

2. Description of the Related Art A token bus type network system uses a token passing type network system for a bus type network. In this token bus system network system, communication between nodes as shown in FIG. 6 is performed by using tokens as nodes 101 to 102, 102 to 103, 103.
To 104, 104 to 105, and so on, to perform communication. Each node is always in a reception standby state except when transmitting, and when one node transmits, all other nodes can receive it through the bus line (indicated by a dotted line in FIG. 6).
However, the token can be received only by the node (indicated by the solid line in FIG. 6) corresponding to the destination (destination) address attached to the token, and in this case, transmission from the nodes 101 to 102 is performed. Is. This destination address is always specified to be the node next to the node that transmitted. Then, only the node that received this token can send it, and if there is data to send, the destination address of the destination node (address of the next node) in the token and the destination node address to send the data And attach the data and send. When there is no data to send, only the destination address is updated to the address of the next node and the token without data is sent.

The greatest feature of this token bus system is that since only the node that has received the token can transmit, only one token is flowing in the bus at any time, so that no communication collision occurs. There is an advantage that it is not necessary to perform communication disappearance due to collision, or to retransmit lost communication.

However, in such a system in which tokens are sent in sequence to transfer data, even if it becomes necessary to transmit data urgently, it is necessary to wait until the token comes around to its own node. , In a network to which many nodes are connected, the value of urgent data is lost while waiting for tokens.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is, in a token bus system network system, when emergency data transmission is required, there is no need to wait for data transmission, and the urgency is not impaired. It is to provide a network system.

[0006]

[Means for Solving the Problems] In the token bus type network, the above objects are to detect an emergency data transmitting means for transmitting emergency data to the network as needed, and to detect the emergency data in the network line. An emergency data detection unit and a collision detection unit that monitors a flow of data and a collision in the network line at the time of transmitting the emergency data by the emergency data transmission unit, and perform transmission and reception of the emergency data. It is achieved by a characteristic network system.

[0007]

In the network system of the present invention configured as described above, the token bus protocol control unit 1 controls transmission and reception of normal communication, reception of tokens and generation of a token data set at the time of transmission. At the same time, when the emergency data needs to be transmitted, a token data set of the emergency data is generated as the emergency data transmitting means, and the emergency data is transmitted. When the token is detected, the emergency data detection unit 2 detects and determines whether the token is urgent. When the emergency token is detected, the normal data transmission / reception state is interrupted and the token bus protocol control unit 1 receives the emergency reception process. It is something to do. The collision detection unit 3 monitors the state of the line at the time of emergency data transmission, monitors the free state of the line and the presence or absence of data collision, and notifies the token bus protocol control unit 1 of the state.

In the network of the present invention, the information processing device (node) that has made an urgent need for data transmission can generate a token by itself regardless of the presence or absence of the token and directly transmit the data. After sending the emergency data, the new token works as a normal token and the old token disappears. Also, during emergency data transmission by the collision detection unit, it is possible to monitor the line and feed back the state in the event of a data collision,
It is possible to prevent the emergency data transmission from disappearing due to the data collision.

[0009]

EXAMPLES The present invention will be described below with reference to examples. Figure 1
FIG. 3 is a block diagram of a part that controls communication of each node in one embodiment of the network system according to the present invention,
FIG. 2 is a flow chart for explaining the flow of data transmission / reception.

Data transmission / reception will be described below.

In the normal state (when there is no urgent transmission or urgent reception), the nodes other than the node performing the transmission process are always in the reception standby state (S1 to S4), and the token is transmitted to the bus. Then, all nodes can detect the token in the bus (S2).

The normal token data set is shown in FIG. 5a.
And the destination node address 51 in which the node number next to the node that transmitted the token is always specified,
It comprises a destination node address 52 indicating a destination node of data, a data area address 53, and a confirmation address 54 for confirming receipt of data and returning it to the transmitting node.

Each node detecting this token first determines whether the detected token is urgent (S
3). This is to check whether the emergency token is always sent by the emergency data detector 2. If the token data set does not have the emergency flag, the destination 51 of the token data set is checked next (S4). If the destination of the token is not the own node, the process returns to S1 and the reception standby state is held.
If the destination is the own node, next, referring to the destination node address 52 of the token data set, whether there is data for this token and if there is data, is it the data intended for the own node? Is determined (S
5) If the purpose is the own node, the data is stored, and a flag for identifying that the data has been received is written in the confirmation address (S10). Next, after storing the data and when there is no data in S5, it is determined whether or not there is transmission data (S
6), if there is send data, the destination address of the node to send to the token data set as normal send processing 5
2 and the data 53 to be sent are written (S11). Then, the address of the node next to the own node is added to the destination address 51 in the token data set and the token is sent (S
7). The token bus protocol control unit 1 controls these communications.

Next, the case of performing emergency data transmission will be described. When it becomes necessary to perform the emergency transmission (S1) while waiting for the reception, the process proceeds to the emergency data transmission process (S8).
FIG. 3 is a flow chart for explaining the flow of emergency data transmission processing.

First, the collision detection unit 3 determines whether or not there is communication data or the like flowing in the bus line (S12). If the line is free, information indicating that the line is free is tokenized. The bus protocol control unit 1 is notified, and the line is monitored until the emergency transmission process is completed. After confirming that the line is open, the token data set is shown in Fig. 5b.
The token is transmitted as shown in (S13). This token data set has an emergency flag address 55 representing an emergency token at the beginning, and is otherwise the same as the token data set in the normal state, but the destination node address 51 and the destination node address 52 are the same node. It is supposed to be represented.

During the communication, the collision detection unit 3 monitors the line, and if a data (a token during communication) collision occurs during the communication (S14), the process returns to S13 to perform the emergency transmission again. In the normal state, the line monitoring during this emergency communication is always one data (token during communication) in the line.
Since it is only flowing, there is no possibility of data collision, so it is not necessary to monitor the line, but during emergency transmission, it is confirmed that the line is open once before transmission, but the transmission process Since other nodes may send tokens during the execution of, the other data (regular tokens or emergency tokens sent by other nodes) are flowing in the line, and that data collides with the emergency token. This is done because there is a possibility. When the emergency transmission process is completed, the process returns to the normal reception standby state (S1-4).

Next, the emergency data reception will be described. FIG. 4 is a flow chart for explaining the flow of emergency data reception processing.

In the normal reception standby state (S1 to 4), each node that has detected the token first determines whether the token detected by the emergency data detection unit 2 is urgent (S3), and sets the token data set. When the urgent flag is attached, the urgent data detection unit 2 informs the token bus control unit 1 that the urgent data has been detected, and shifts the processing to the urgent data reception processing.

Each node that has detected the urgent data judges whether the detected token is data intended for its own node (S15), and if it is addressed to its own node, stores the data (S16), A new normal token data set (Fig. 5a) is generated, and the confirmation flag 54 that has received the data is added to this and transmitted (S17). In parallel with this, regardless of whether the emergency token is addressed to its own node or another node, it is judged whether or not it currently has a token (S18), and if so, the token is erased (S19). ). Then, the presence / absence of the transmission data is determined (S20), and if the transmission data is to be transmitted on the token that has been erased, the transmission data is put in the stack and held, and when the next token comes around. Retransmission is performed (S21). When these parallel processes are completed, the normal reception standby state is restored.

[0020]

As described above, the network system of the present invention does not impair urgency in a token bus system network, especially when many information processing devices (nodes) are connected. Information can be sent and received.

[Brief description of drawings]

FIG. 1 is a block diagram of a communication control unit according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating transmission / reception according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating an emergency data transmission according to an exemplary embodiment of the present invention.

FIG. 4 is a flowchart illustrating an emergency data reception according to an embodiment of the present invention.

FIG. 5 is a diagram for explaining a token data set handled in an example according to the present invention.

FIG. 6 is a diagram for explaining a conventional token bus system network.

[Explanation of symbols]

1 ... Token bus protocol control unit, 2 ... Emergency data detection unit, 3 ... Collision detection unit, 51 ... Destination address, 52 ... Destination address, 53 ... Data address, 54 ... Confirmation flag address, 55 ... Emergency flag address.

Claims (1)

[Claims] 1. In a token bus system network, an emergency data transmission means for transmitting emergency data to the network as needed, an emergency data detection unit for detecting the emergency data in the network line, and the emergency data. A network system, comprising: a collision detection unit that monitors a data flow and a collision in the network line when transmitting the emergency data by the transmission unit, and transmits and receives the emergency data.