JPH08328981A - Node buffer overflow prevention control method - Google Patents

Abstract

(57) [Abstract] [Purpose] Efficiently prevent buffer overflow in the nodes that make up a contention-based network. [Configuration] A buffer overflow prevention control method in a node that configures a contention-type network, in which the remaining buffer memory number of the buffer is measured, and when the remaining buffer memory number becomes less than a preset value ( In step 101), dummy data is sent to the network (step 102) at least until the number of remaining buffer memories becomes larger than a preset value (specified value) (step 103).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing buffer overflow of nodes constituting a network, and more particularly to efficiently prevent buffer overflow of a node of a network for establishing a data link by a contention method. The present invention relates to a buffer overflow prevention control method suitable for a node.

[0002]

2. Description of the Related Art The amount of data flowing on a network is increasing with the scale of the network and the diversification of information. Therefore, it is becoming necessary to take measures against the buffer overflow of the nodes that make up the network. Conventionally, as a countermeasure against such a buffer overflow, it has been considered to give priority to nodes and data and process the one with a high priority first. For example, Japanese Patent Application Laid-Open No. 3-85839 discloses a technique of determining transmission data by comparing the degree of congestion with the priority of data.

As described above, the conventional control for preventing buffer overflow is generally performed by the control of the upper layer. Therefore, in order to prevent the buffer overflow, it is necessary to change the software of the existing node, which requires cost and time.

[0004]

The problem to be solved is that in the conventional technique, the buffer overflow of the node cannot be prevented unless the software of the upper layer level is changed. The object of the present invention is to solve these problems of the prior art and to efficiently prevent the buffer overflow by making a change in the lower layer level only to the node that needs the buffer overflow control, and it does not require cost and time. It is to provide a buffer overflow prevention control method for a node.

[0005]

To achieve the above object, a buffer overflow prevention control method for a node according to the present invention is a buffer overflow prevention control method for a node constituting a contention type network,
When the remaining buffer memory number of the buffer is measured and this remaining buffer memory number becomes less than the preset value,
The dummy data is sent to the network at least until the number of remaining buffer memories becomes larger than a preset value.

[0006]

In the present invention, the buffer overflow of a node is prevented by utilizing the characteristic of the contention system. That is, in the contention method, while one node A is sending data, another node cannot send data to the node A. Therefore, from another node to node A
When a large amount of data exceeding the processing capacity of the node A is sent to the network and the remaining buffer memory number of the node A becomes smaller than a predetermined value, the node A sends dummy data to the network. As a result, it is possible to prevent another node from newly sending data to the node A, and it is possible to prevent the buffer overflow of the node A.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a flow chart showing an embodiment of the operation related to the buffer overflow prevention control of the node of the present invention, and FIG. 2 is a structural example of a network provided with a node for performing the buffer overflow prevention control of the present invention. It is a block diagram shown. In FIG. 2, 1 to 3 are nodes including personal computers, workstations, host computers, and the like, and 4 is a network connecting the nodes 1 to 3. The network 4 is a contention type network, and a typical example thereof is Ethernet. Here, the scale and configuration of the network can be arbitrary.

The node 3 includes a buffer 3a for accumulating data sent from the nodes 1 and 2 via the network 4, a processing section 3b for processing the data accumulated in the buffer 3a, and a buffer 3a. When the remaining buffer memory number is measured and the remaining buffer memory number becomes smaller than a preset value, dummy data is transmitted to the network 4 at least until the remaining buffer memory number becomes larger than the preset value. Accordingly, the buffer overflow prevention control unit 3c for performing the buffer overflow prevention control of the buffer 3a according to the present invention is provided.

The buffer overflow prevention control operation according to the present invention in the node 3 having such a network configuration and node configuration will be described below with reference to the flow chart in FIG. Since the nodes 1 and 2 in FIG. 2 send a large amount of data to the node 3, the processing of the node 3 cannot catch up, and the number of remaining buffer memories of the buffer 3a of the node 3 becomes smaller than a preset value (specified value). (Step 101). In this case, node 3 in FIG.
Is controlled by the buffer overflow prevention control unit 3c for a certain period of time.
Dummy data is sent to the network 4 (step 1
02).

In this way, while the node 3 of FIG.
2 is a contention system, the nodes 1 and 2 in FIG. 2 cannot flow new data. During this time,
Node 3 of the node processes the data in the buffer 3a by the processing unit 3b to recover the number of remaining buffers (step 10).
3).

As described above, when the number of remaining buffer memories of the buffer 3a of the node 3 becomes smaller than the predetermined value, the node 3 sends the dummy data to the network by the buffer overflow prevention control unit 3c so that the other nodes can operate. The buffer overflow is prevented by preventing the transmission of new data. In this case, it is sufficient to change the lower layer level only to the node 3 that needs the buffer overflow control.

Next, an embodiment in which the present invention is applied to a network connection device will be described with reference to FIG. FIG.
It is a block diagram which shows the other structural example of the network which provided the node which performs the buffer overflow prevention control which concerns on this invention. The network in this example is composed of a plurality of networks 35 and 36, and the network 35 has nodes 3
1, 32, and a node 34 is connected to the network 36. Then, the networks 35, 3
6 are interconnected by a node 33.

The nodes 31, 32 and 34 are the same as in FIG.
The node 33 is a network connection device such as a router or a bridge, which includes a personal computer, a workstation, a host computer, or the like. Like the node 3 in FIG. 2, this node 33 has a buffer overflow prevention control unit and performs the buffer overflow prevention control according to the present invention. The network 35 is a contention-type network, and a typical example thereof is Ethernet. The network 36 can be realized by a network other than the contention system network. Here, the scale and configuration of the network can be arbitrary.

When the nodes 31 and 32 send a large amount of data to the node 34 such that the processing of the node 33 cannot catch up, the number of remaining buffer memories of the node 33 decreases. When the number of remaining buffer memories becomes smaller than the specified value, the node 33 sends dummy data to the network 35 for a certain period of time. While the node 33 is sending the dummy data to the network 35, the network 35 is in the contention system, so that the nodes 31 and 32 cannot flow new data. During this time, the node 33 can process the data in the buffer to recover the number of remaining buffers.

As described above with reference to FIGS. 1 to 3, in the node buffer overflow prevention control method of this embodiment, in the contention type network, the number of remaining buffer memories of a certain node constituting the network is When the number is less than the default value, dummy data is sent from this node to the network to prevent other nodes from sending new data, thereby preventing buffer overflow. In this buffer overflow prevention control method, it is only necessary to change the lower layer level to the node that needs the buffer overflow control, which requires more cost and time than the conventional technique involving the change of the upper layer level. Absent.

The present invention is not limited to the embodiment described with reference to FIGS. 1 to 3, and various modifications can be made without departing from the scope of the invention. For example, in the present embodiment, when the number of remaining buffer memories becomes smaller than the specified value, the dummy data transmission is stopped when the number of remaining buffer memories becomes larger than the specified value. It is also possible to continue sending the dummy data for a certain period of time after the value exceeds the specified value.

[0017]

According to the present invention, buffer overflow can be efficiently prevented by simply changing the lower layer level only to the node which needs the buffer overflow control, and the conventional upper layer level change is involved. It can save costs and time over technology.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of an operation relating to buffer overflow prevention control of a node of the present invention.

FIG. 2 is a block diagram showing a configuration example of a network provided with a node for performing buffer overflow prevention control according to the present invention.

FIG. 3 is a block diagram showing another configuration example of a network provided with a node for performing buffer overflow prevention control according to the present invention.

[Explanation of symbols]

1-3: nodes, 3a: buffer, 3b: processing unit, 3
c: buffer overflow prevention control unit, 4: network, 3
1-34: nodes, 35, 36: networks.

Claims (1)

[Claims] 1. A buffer overflow prevention control method in a node that constitutes a contention-type network, wherein the number of remaining buffer memories of the buffer is measured,
When the number of remaining buffer memories becomes smaller than a preset value, dummy data is sent to the network at least until the number of remaining buffer memories becomes larger than the preset value. Preventive control method.