AS6802 synchronization frame transparent transmission system and method in TTE switch

Abstract

The invention belongs to the technical field of communication, and discloses an AS6802 synchronization frame transparent transmission system and method in a TTE switch, and the AS6802 synchronization frame transparent transmission system in the TTE switch comprises a receiving first-in first-out queue FIFO module, a receiving interception module, a frame analysis module, a frame information cache management module, a synchronization frame transparent transmission management module, and a sending first-in first-out queue FIFO module. The AS6802 synchronous frame transparent transmission method in the TTE switch comprises the steps of synchronous frame caching, interception receiving time and frame analysis, frame information and receiving time point cache management, whether a synchronous frame transparent transmission management module is idle or not, synchronous frame synthesis, synchronous frame sending and synchronous frame arbitration. According to the method, the problem of transparent transmission of the synchronization frame is solved, the number of nodes which can be supported by the TTE system is increased, the residence time and the maximum transmission delay of the system synchronization frame are reduced, and the adaptability and the clock synchronization precision of the TTE switch are improved.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to a transparent transmission system and method of an AS6802 synchronization frame in a TTE switch. Background technique [0002] At present, with the rapid development of science and technology, the modern industrial control system is becoming larger and larger, and the high-precision and high-reliability synchronous Ethernet switching network composed of a single switching device is increasingly unable to meet the demand. The high-accuracy, high-reliability synchronous Ethernet switching network is more and more concerned. The SAE AS6802 standard defines time-triggered services for Ethernet networks, providing high-precision, high-reliability, and fault-tolerant precise clock synchronization for time-triggered Ethernet. Implementing the synchronization client function component defined by AS6802 synchronization in the TTE switch can realize the cascaded clock sy...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that since this method does not involve the transparent transmission of synchronization frames, it can only be used for clock synchronization of a network with a single switching device, and is not suitable for clock synchronization of a network of multiple switching devices. Form a large-scale time-triggered Ethernet system

The disadvantage of this method is that, first, when the switch forwards, the synchronization frame is treated as an ordinary Ethernet frame, and the priority of the synchronization frame is lower than that of the TT service frame, which causes the transmission delay of the synchronization frame to increase and crowds the TT of the switch. The transmission bandwidth of the business, especially the transmission bandwidth occupied by multi-level cascading, will be unbearable; second, the synchronization frame switching plane is specially set up to separate the time synchronization unit from the transparent transmission of the synchronization frame, which wastes logical resources and must be static Configuring the switching path greatly reduces the flexibility and greatly increases the delay; third, the forwarding delay of the synchronization frame does not take into account the PHY delay of the board, and the synchronization accuracy cannot be guaranteed, especially when multi-level cascading may cause synchronization failure; Fourth, the priority of the synchronization frame is not set to the highest priority, which will cause the device to fail to synchronize in high-density business transmission

[0006] (1) The existing AS6802 standard-based switching device clock synchronization method does not involve the transparent transmission of synchronization frames, so it can only be used for clock synchronization of a network with a single switching device, and is not suitable for clock synchronization of a network of multiple switching devices , cannot constitute a large-scale time-triggered Ethernet system

[0007] (2) In the prior art, when the switch forwards, the synchronization frame is treated as an ordinary Ethernet frame, and the priority of the synchronization frame is lower than that of the TT service frame, resulting in an increase in the transmission delay of the synchronization frame, and crowding out the transmission of the TT service of the switch Bandwidth, especially the transmission bandwidth occupied by multi-level cascading will be unbearable

[0008] (3) Existing Ethernet switches specially set up a synchronization frame switching plane to separate the time synchronization unit from the transparent transmission of the synchronization frame, which wastes logical resources and must also statically configure the switching path, greatly reducing flexibility and greatly increasing delay

[0009] (4) In the prior art, the forwarding delay of the synchronization frame does not consider the PHY delay of the board, and the synchronization accuracy cannot be guaranteed, especially when multi-level cascading may cause synchronization failure; meanwhile, the priority of the synchronization frame is not set to The highest priority, which will cause the device to fail to synchronize during high-density business transmission

In the existing technology, when the switch forwards, the synchronization frame is treated as an ordinary Ethernet frame, which not only does not comply with the AS6802 standard, but also greatly increases the transmission delay of the synchronization frame, which affects the synchronization accuracy and even causes the problem of synchronization failure

The difficulty to solve is not only to ensure the function and performance requirements of synchronization, but also to ensure the available bandwidth of TT services as much as possible, because the purpose of synchronization is for the transmission of TT services. If the synchronization process occupies too much bandwidth, it will make the entire network Reduced efficiency

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