Research On Highly Reliable Gigabit Ethernet Switch

Nowadays spacecrafts are becoming more and more advanced. They have diversiform and complex functions. This means the internal control system of spacecrafts will become more complex and data communications of them will also become very diversiform. Along with the increase of transmission requirements of instructions and data, and with the increase of communication performance requrements in spacecrafts'internal network, traditional field bus can hardly meet these needs, so Ethernet, for its general-purpose, openness, stability, high speed and low cost, becomes one of the options for spacecrafts'internal networks.Along with the developments of computer technology and communication technology, Ethernet technology achieved a huge progress in the last 30 years. And its range of applications becomes wider and wider, not only in office automation, but also in industrial control, national defense, aerospace and so on. However, because commercial Ethernet devices can not guarantee real-time and deterministic performance, and they also have no special mechanism to ensure high reliability, they can not be used in industrial control, national defence and aerospace fields. It is necessary to design dedicated Ethernet devices for such fields, addressing their specific needs with special features.In this thesis, we designed and implemented a gigabit Ethernet switch for spacecrafts'internal network, meeting its high reliability and low-latency requirements. This thesis studied the existing highly reliable and low-latancy Ethernet technology, such as industial Ethernet, AFDX network, time-triggered Ethernet, especially in their mechanisms to ensure high reliability and low latency.To ensure high reliability, this thesis proposes a multi-level method, including manufacturing material level, logic design level and transmission protocol level. In the manufacturing material level, the use of SOI technology in combination with anti-radiation reinforcement measures can ensure the switch come up to the spacecrafts' anti-ratiation standards. In the logic design level, a series of redundancy mechanisms in combination with CRC can ensure the network's high reliability. In the transmission protocol level, Acknowledgment-based User Datagram Protocol (AUDP) we proposed can ensure the correctness of the transmission of instructions and critical data.To ensure low latency, this thesis proposes a full-duplex switching technology with priority and flow control. To test whether this mechanism can meet the needs of spacecrafts'internal network, this thesis performs a theoretical analysis and an experimental simulation. The results of theoretical analysis and experimental simulation show that this mechanism is enough to meet the spacecrafts'stringent requirements in low latency.Finally, based on the proposed high reliability and low latency guarantee mechanism, this thesis designs and implements a gigabit Ethernet switch that meets the high reliability and low latency requirements of spacecrafts' internal network.