Data transmission mode based on bandwidth and time sequence distribution

Abstract

The invention relates to a data transmission mode based on bandwidth and time sequence distribution. The method comprises the following steps: carrying out bandwidth allocation and time sequence allocation according to the bandwidth of a transmission network and the unit time data output quantity of each network node, synchronously receiving data output by each network node in real time at a network switch end, repackaging and packaging according to the bandwidth allocation, and then sending according to the allocated time sequence. According to the invention, due to the adoption of bandwidth and time sequence distribution, real-time synchronous transmission of data is realized. The method is suitable for transmission networks with fixed data transmission paths and transmission targets and periodic data output, such as data acquisition system transmission networks, measurement and control system transmission networks and the like.

Description

Technical Field

[0001] The present invention belongs to the field of data communication. Specifically, an Ethernet switch is improved by adopting a data transmission method based on bandwidth and timing allocation to achieve synchronous transmission of data in a specific transmission network. Background Art

[0002] Due to the widespread application of Ethernet technology, the vast majority of data transmission networks use Ethernet to complete data transmission. Therefore, Ethernet has gradually become the mainstream architecture of data transmission networks. Building a data transmission network with Ethernet has the advantages of low cost, easy implementation, and wide sources of related components. However, for an application scenario where multiple data output devices simultaneously output data to the same target node, the uncertainty of transmission delay brought by traditional Ethernet not only has low efficiency but also risks data loss.

[0003] Currently, common transmission networks basically connect all network nodes through an Ethernet switch in a star topology. The data output node directly sends data to the target node through the switch, or the data output node outputs data in a broadcast manner, and then the target node receives this data. In such an environment, many times, multiple output nodes need to send data to the same target node at the same time, which will result in routing competition and a significant decrease in transmission efficiency. When the total amount of data output is large, data loss may even occur.

[0004] The present invention re - encapsulates and forwards the data output by each node at each port of the switch according to a preset frequency and bandwidth, avoiding transmission path competition, thereby achieving synchronous transmission of network data and solving the problem of uncertain Ethernet transmission delay at the same time. Summary of the Invention

[0005] The present invention mainly aims at systems composed of network nodes with single functions, such as measurement and control systems, data acquisition systems, monitoring systems, etc. Nodes in such data transmission networks can be divided into two categories. One is the data output node, such as a data acquisition node, an image recording node, etc. The other is the data demand node, such as a data processing node, a data recording node, a monitoring node, etc. In such systems, there is basically no communication between data output nodes, and their data output shows periodic characteristics, that is, the total amount of data output in each cycle is constant and the output frequency is relatively fixed. In addition, the system has certain requirements for data transmission synchronization and real - time performance. Therefore, if a traditional Ethernet is directly used to build the transmission network of such a system, it will face defects such as transmission path competition and uncertain transmission delay. Therefore, the Ethernet needs to be improved to meet the requirements of system data synchronous transmission and real - time transmission.

[0006] For specific applications with the above characteristics, the frequency of forwarding data can be determined according to the network transmission delay index, and the amount of data that each node can forward each time can be determined according to the total amount of data output by each node per unit time.

[0007] Based on the general Ethernet underlying communication, the present invention receives the Ethernet data packets sent by each node in real-time and in parallel during the operation of the system, and unpacks and caches the data. That is, at the aggregation and switching nodes of the transmission network, a dedicated transceiver module with data caching function is configured for each access device. In this way, the entire transmission network can receive the data output by each access device in real-time and in parallel, and store the received data in the data cache of the transceiver module in real-time.

[0008] At the same time, according to the above forwarding frequency and the amount of forwarded data, the transceiver module forwards the data to all data demand nodes in sequence according to the node number. For convenience, generally the original packet is forwarded. Only when individual data packets of a node exceed the amount of data that can be forwarded each time, the method of splitting them into multiple data packets and then re-encapsulating and transmitting them is used to complete the forwarding of large data packets.

[0009] Due to the adoption of real-time parallel reception and sequential distribution for transmission, it is ensured that there is no path conflict in the data transmission from the data output node to the sending target node, and the entire transmission network realizes synchronous real-time transmission.

[0010] When using the present invention to construct the transmission network of the system, all nodes can be compatible with any device supporting Ethernet as its node. Compared with the traditional Ethernet, the differences are as follows: 1) The traditional Ethernet is an asynchronous transmission network, while the transmission network constructed based on the present invention can achieve synchronous transmission; 2) The traditional Ethernet may have transmission path conflicts, resulting in uncertainty in data transmission delay, while the transmission delay of the transmission network constructed based on the present invention can be controlled; 3) The transmission network constructed by the present invention is only applicable to applications with periodic characteristics of output data and the characteristic that the amount of data output by the output node per unit time is fixed. While the traditional Ethernet has no such limitations.

[0011] The following describes the specific implementation steps of the present invention: 1) First, according to the principle shown in the appendix Figure 1 Construct a network switch that supports multiple access ports: (1) Equip each access port with at least one Ethernet interface that supports Category 6 twisted pair. At the same time, each port is equipped with an independent receive cache module for directly receiving the data output by the device connected to this port. This module also has the function of unpacking and reconstituting; (2) The switch is equipped with a forwarding module, which is used to sequentially retrieve data packets not exceeding the single - transmission volume from the caches of each port at a preset frequency and forward them to the target node; (3) A sending module is equipped at each access port, which is used to select the data required by the access device and send it through the network interface; 2) Then, all the data output devices and data - demand devices of the system are respectively connected to the respective ports of the above - mentioned switch through Ethernet cables; 3) During the operation of the system, the data output device outputs data to the above - mentioned switch through the network interface, and the received buffer module of the corresponding port of the switch receives it in real - time and stores it in the corresponding cache. If the received data packet is larger than the single - transmission volume set in advance, the data packet is split and encapsulated into multiple data packets and then stored in the cache; 4) The forwarding module of the switch periodically (at a preset frequency) sequentially reads data packets not exceeding the single - transmission volume from the data caches of each port and forwards them according to the destination address in the packet; 5) After receiving the data packet sent by the forwarding module, the sending module of the switch sends the data packet through the network interface of the port to the corresponding access device, that is, the target device of the data packet. Description of the Drawings Attached Figure 1 : Block diagram of the implementation principle of transmission based on bandwidth and timing allocation.

Claims

1. A data transmission method based on bandwidth and timing allocation, characterized in that: At the specific Ethernet network switch end, synchronous parallel reception is adopted and the method of bandwidth and timing allocation is increased to synchronously transmit the data sent by the data output node to the target node.

2. The synchronous parallel reception according to claim 1, wherein Each network port of the Ethernet switch independently and parallelly receives the network packets sent by the accessed devices and completely unpacks them into raw data.

3. The bandwidth allocation according to claim 1, characterized in that When the data output nodes are set in the switch for data repackaging, the packet length of the encapsulated network packets is restricted to ensure that all the data sent by all nodes within a unit time is completely forwarded by the switch without any transmission conflicts.

4. The timing allocation according to claim 1, characterized in that Within a unit time, each port of the switch repackages and outputs the network packets and forwards them according to the preset frequency and transmission order.

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