JPH04352051A - Information processing network system - Google Patents

Abstract

PURPOSE:To effectively utilize a line by reducing the collision of data when the load of a network is high. CONSTITUTION:In this information processing network system connecting a master machine M to plural slave machines through a local area network(LAN) 10 based upon a carrier sensing multiplex access(CSMA) system, a line monitoring means 1 in the master machine M monitors the LAN and determines whether the management of transmission data is to be executed or not, a line allocation determining means 4 determines the transmission enabled time allocation of respective slave machines by referring line data transmission history stored in a packet information data base and controls data transmission. Thereby even when the using rate of the line is high and much data collision is generated, the utilization rate of the line can be improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION The present invention is used for data transmission over a network using the CSMA (Carrier Sense Multiple Access) method. The present invention relates to an information processing network system that controls packet transmission over a line in an environment where the load on the line is high and data collisions occur frequently.

0002

[Prior Art] Conventionally, data transmission using the CSMA method detects the line usage status and confirms that the line is not in use before transmitting data. When transmission is performed, a collision may occur and valid data may not flow on the line, so a CSMA/CD (carrier sense multiple access/collision detection) method is adopted as a method for detecting collisions. This method interrupts data transmission when it detects that a collision has occurred.
Data is retransmitted after a random period of time has elapsed.

0003

[Problems to be Solved by the Invention] The conventional data transmission method described above requires retransmission in environments where a large number of machines are connected to the line, resulting in a high line load and frequent collisions of transmitted data. He was trying to recover only by doing so. Conventional methods like this do not cause problems when line congestion is temporary and the line opens after a certain period of time, but if congestion continues for a period of time, retransmission may be difficult. However, there is a high possibility that data collisions will occur, which reduces the effective utilization rate of the line.

[0004] The present invention solves this problem by providing a system that can reduce packet collisions by scheduling the line usage of each machine when it becomes difficult for valid data to flow on the line. The purpose is to provide

[0005]

[Means for Solving the Problems] In the present invention, one master machine and a plurality of slave machines are connected via a local area network based on a CSMA (carrier sense multiple access) system, and packet information is transmitted to the master machine. The master machine and the slave machine each include a transmission management means for managing transmission and reception of data, a data transmission means for transmitting data, and a data reception means for receiving data. In the information processing network system, the master machine includes a line monitoring means for monitoring the usage status of the line, and a method for determining whether or not to perform line control based on the monitoring information of the line monitoring means, and when performing line control. The present invention is characterized by comprising a line control starting means for notifying each of the slave machines to that effect, and a line allocation determining means for calculating a data transmission time of each of the slave machines when line control is performed.

[0006]

[Operation] Echo packets are sent at fixed time intervals, and depending on whether or not there is a response, the usage status of the line is monitored and it is decided whether or not to manage the transmitted data. Data transmission is controlled by referring to the data transmission history and allocating times when each machine can transmit.

[0007] When the load on the line increases and packet collisions occur frequently, making it difficult for valid data to flow on the line, each slave machine uses the line according to the situation. By performing scheduling for this purpose and transmitting and receiving data based on the schedule, it is possible to reduce the frequency of packet collisions and improve the effective utilization rate of the line.

[0008]

Embodiments Next, embodiments of the present invention will be explained based on the drawings. Figure 1 is a block diagram showing the configuration of an embodiment of the present invention, Figure 2
1 is a block diagram showing an example of the configuration of a network according to an embodiment of the present invention. FIG.

In the embodiment of the present invention, one master machine M and a plurality of slave machines A, B, C, D, E, F, and G are connected via a local area network 10 based on the CSMA system. A master machine M and slave machines A, B, C, D, E, F, G are provided with a packet information database 7 for storing packet information.
A transmission management means 5 for managing data transmission and reception, respectively.
, a data transmitting means 3 for transmitting data, and a data receiving means 6 for receiving data.Furthermore, as a feature of the present invention, the master machine M is equipped with a line monitoring means 1 for monitoring the usage status of the line. Based on the monitoring information of the line monitoring means 1, it is determined whether or not to perform line control, and when performing line control, slave machines A, B, C, D, E, F, G
Line control starting means 2 notifies each of them, and slave machines A, B, C, D when line control is performed.
, E, F, G data transmission times.

[0010] Next, a description will be given of the transmission packet management operation at the time of line congestion in the network according to the CSMA method according to the embodiment of the present invention configured as described above.

[0011] The line monitoring means 1 transmits echo packets at regular time intervals, monitors the usage status of the line based on whether or not a response is returned, and prevents echo packet responses from being lost due to a high line usage rate. If such a situation occurs, the line control starting means 2 is notified that line control is necessary.

The line control starting means 2 generates a line control start notification packet, and sends the generated packet to the data transmitting means 3 to request transmission. The data transmitting means 3 transmits normal data and line control start notification packets and broadcasts them to all machines on the line. The broadcast line control start notification packet is
The data is received by the data receiving means 6 of each computer. When the data receiving means 6 receives the line control start packet, it notifies the transmission management means 5 that line control will be performed.

[0013] When line control is started, the transmission management means 5 suppresses data transmission, and data transmission is performed according to the line usage permission time of each machine calculated by the line allocation determining means 4.

The line allocation determining means 4 calculates the line use time of each machine based on the information held in the packet information database 7, and transmits a line use allocation notification packet. Each machine receives the line usage assignment notification packet by the data receiving means 6, and passes the line usage assignment information to the transmission management means 5. The transmission management means 5 transmits data based on this information.

Next, the determination of the allocated time for machines using the line will be explained. When each machine on the line is given a chance to transmit a packet once, the transmission management unit time is T, a transmission time S of one packet is assigned to a machine that has transmitted data within the last nT. A specific transmission time is not assigned to a machine that has not transmitted within nT, but a fixed time is assigned to a group of machines that have not transmitted.

FIG. 3 is a diagram showing an example of information held by the packet information database in the embodiment of the present invention, and FIG. 4 is a diagram showing an example of transmission management unit time in the embodiment of the present invention. Here, the operation of the embodiment of the present invention will be explained in more detail using FIGS. 2, 3, and 4. To simplify the explanation, a network in which eight machines, a master machine M and slave machines A to G, are connected on a line as shown in FIG. 2 will be explained as an example.

If the data transmission status of the past 5T is as shown in FIG. 3, one packet transmission time S is allocated to the master machine M and slave machines A, C, E, and F, respectively, as the management time of Tn. The circle in Figure 3 indicates Tn-x.
Indicates that data was sent at the same time. Here, it is assumed that half of the machines that have not sent data within 5T may send data,
[Machines transmitting data/2+1] S is assigned to a group of machines that are not transmitting data. As a result, 2S time is allocated to slave machines B, D, and G.

The present invention is characterized in that, based on the idea that machines that have recently used the line are likely to transmit again, wasteful line usage time is not allocated to machines that are unlikely to use the line. The transmission management unit time Tn is as shown in FIG.

Next, a method of notifying each slave machine of the line transmission management unit time T calculated by the master machine M will be explained. The master machine M allocates transmission time on the line to the slave machine, which has a transmission management unit time T.
, the transmission start time Sx of each machine, and a flag identifying that the transmission time is exclusive to that machine as management data. For machines to which transmission time has not been allocated, transmission start time S0, transmission management unit time T1,
Management data with a flag indicating that an arbitrary host computer can transmit the number of transmittable packets Pn and a transmission time is broadcast.

[0020] When the slave machine receives management data addressed to its own machine, if there is data to be transmitted, the slave machine transmits the data at the transmission start time Sx according to the contents of the management data. If the management data does not arrive at the own machine, an attempt is made to send the data after S0 + (random number %Pn) x S time according to the broadcasted management data.

Next, a method for canceling line control when the line usage rate decreases will be explained. The line allocation determining means 4 determines that the number of data transmitting machines has decreased from the information in the packet information database 7, generates a line control cancellation notification packet, and transmits the generated packet to the data transmitting means 3 to issue a cancellation request. conduct. The slave machine that receives the line control cancellation notification packet in response to this request learns that the line control has been canceled and performs data transmission when there is a transmission request.

[0022]

As explained above, according to the present invention, when the line load increases and packet collisions occur frequently, making it difficult for valid data to flow on the line, each slave machine Scheduling line usage has the effect of reducing packet collisions and improving the effective utilization rate of the line.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a network configuration in an embodiment of the present invention.

FIG. 3 is a diagram showing an example of information held by a packet information database in an embodiment of the present invention.

FIG. 4 is a diagram showing an example of transmission management unit time in the embodiment of the present invention.

[Explanation of symbols]

1. Line monitoring means 2 Line control starting means 3 Data transmission means 4. Line allocation determining means 5 Transmission management means 6 Data receiving means 7 Packet information database

Claims (1)

[Claims] 1. One master machine and a plurality of slave machines are connected via a local area network using a CSMA (carrier sense multiple access) method, and the master machine is provided with a packet information database for storing packet information, Each of the master machine and the slave machine includes a transmission management means for managing transmission and reception of data, and a data transmission means for transmitting data;
In an information processing network system comprising a data receiving means for receiving data, the master machine includes:
A line monitoring means for monitoring the usage status of the line, and a line for determining whether or not to perform line control based on the monitoring information of this line monitoring means, and notifying each of the slave machines to that effect when performing line control. An information processing network system comprising: control starting means; and line allocation determining means for calculating data transmission times of each of the slave machines when line control is performed.