SpaceFibre Network Research Articles

Broadcast Propagation Time in SpaceFibre Networks with Various Types of Spatial Redundancy

Various methods of spatial redundancy can be used in local networks based on the SpaceFibre standard for fault mitigation of network hardware and physical communication channels. Usually, a network developer chooses the method of spatial redundancy according to the number of failures that have to be mitigated, the time required for restoring the normal operation of the network, required overheads and hardware costs. The use of different spatial redundancy mechanisms can cause changes in the structure of the links between network nodes, in case of failure and subsequent mitigation. In turn, this may cause changes in the broadcast transmission paths and the temporal characteristics of their delivery from the source to the receivers. This article focuses on the change in the propagation time of broadcasts in SpaceFibre networks with spatial redundancy. Broadcast propagation rules significantly differ from data-packet propagation rules. Broadcast distribution time is very important for many applications, because broadcasts are generally used to send urgent messages, in particular for time synchronization. Various formal methods have been used to evaluate the propagation characteristics of the broadcast. A method for estimating broadcast propagation time along the shortest routes is proposed. In addition, we provide a formal method to estimate the number of failures, which occurred in the network during the broadcast propagation. This method is based on timed Petri nets; one of its features is the ability to calculate broadcast transmission delays. In addition, as an alternative solution, we propose a method for estimating delays based on time automata theory.

Analysis of the SpaceFibre technology for the high-bandwidth onboard networks

The paper presents an analysis of a prospective international standard SpaceFibre for on board data exchange for different types of aircraft. Paper provides the rationale for using of this standard for new generation on-board networks. The obtained results are based on many years of experience with the SpaceWire/SpaceFibre family of open international standards. The authors present the main problems of SpaceFibre, as well as ways to solve them. The first problem is related to the use of multi-channel data transmission in prospective Russian projects, as well as the need to increase throughput using existing equipment and physical cables. It is necessary to develop new transmission methods and algorithms and create a completely Russian version of the multilane level for the described standard. The second problem relates to the organization of data transmission in SpaceFibre networks with a large number of nodes and a complex scheme of data transfer flows, it is a consequence of an insufficiently developed network level of the standard. The authors give possible ways to solve the identified inconsistences of the standard using the concept of software-reconfigurable networks. The finalization of the SpaceFibre standard in terms of the discussed problems will improve the efficiency of the protocol itself, as well as take into account all possible comments before the stage of creating of a Russian State Standard for SpaceFibre.

Time Synchronization Mechanisms for Spacefibre Networks and Their Implementations

Most onboard embedded systems have real-time requirements. The SpaceFibre standard is developed for onboard local networks. However, the current version of the SpaceFibre standard does not specify any time synchronization mechanisms. The authors consider the mechanisms of time synchronization that are used in the data transmission standards, which are currently used for networks with real-time requirements. In the paper, the authors proposed possible time synchronization mechanisms for the SpaceFibre network, evaluate their characteristics. The authors proposed dynamically reconfigurable Local time controller for implementation of these mechanisms with ASIC.

АППАРАТНО-ПРОГРАММНАЯ ОТРАБОТКА КОММУНИКАЦИОННЫХ ПРОТОКОЛОВ ДЛЯ БОРТОВЫХ СЕТЕЙ

The article deals with the problem of hardware-software research of communication protocols for on-board networks. A system is presented that allows testing the developed SpaceWire and SpaceFibre network equipment. Determination of the main stages of development of the system under consideration for SpaceWire technology demonstrates various network structures that meet the stated requirements for hardware and software testing of network equipment and determines the necessary devices for implementing the theory in practice. One of the sections of the article demonstrates the successful implementation of the proposed theory in practice. The described problems of implementing such a research complex for SpaceFibre technology help to determine the vector of further research.

A representative SpaceFibre network evaluation: Features, performances and future trends

SpaceFibre is a high-speed satellite on-board communication protocol. It allows high data rates (up to 6.25 Gbps per lane), advanced quality of service, fault detection isolation and recovery. Different SpaceFibre nodes can be combined, together with a SpaceFibre routing switch, to form a network. This work aims to describe the set-up of a SpaceFibre network, made of independently developed nodes. The performance of a simplified version of the network is then evaluated and measured, in terms of jitter and latency, for both data packets and broadcast messages, providing a first literature contribution about innovative SpaceFibre network timing performances. It will be a useful indication for future system adopters and could be the baseline for future in-depth measurement and investigation.

SHINe: Simulator for Satellite on-Board High-Speed Networks Featuring SpaceFibre and SpaceWire Protocols

The continuous innovation of satellite payloads is leading to an increasing demand of data-rate for on-board satellite networks. In particular, modern optical detectors generate and need to transfer data at more than 1 Gbps, a speed that cannot be satisfied with standardized technologies such as SpaceWire. To fill this gap, the European Space Agency (ESA) is supporting the development of a new high-speed link standard, SpaceFibre. SpaceFibre provides a data-rate higher than 6.25 Gbps, together with the possibility to use multiple Virtual Channels running over the same physical link, each one configurable with flexible Quality of Service parameters. These features make a SpaceFibre network very appealing but also complex to set up in order to achieve the desired end-to-end requirements. To help this process, a Simulator for HIgh-speed Network (SHINe) based on the open-source toolkit OMNeT++ has been developed and is presented in this paper. It supports the simulation of SpaceFibre and SpaceWire protocols in order to help both the final steps of the standardization process and the system engineers in the setup and test of new networks. SHINe allows to precisely simulate common network metrics, such as latency and bandwidth usage, and it can be connected to real hardware in a Hardware-in-the-Loop configuration.

ESTIMATION OF VIRTUAL CHANNELS BANDWIDTH FOR TRAFFIC MANAGEMENT IN SPACEFIBRE NETWORKS

The application of SpaceFibre network standard and ESDP transport protocol (the previous name is «STP-2») for streaming data transfer in onboard spacecraft networks is considered in the paper. The paper demonstrates that traffic management is needed in SpaceFibre networks. To solve this problem Adaptive Data Streaming Service (ADSS) could be used. ADSS Traffic management is based on the traffic control via changing of SpaceFibre configuration parameters and ESDP protocol’s mechanisms. Genetic Algorithm (GA) is proposed to determine new SpaceFibre configuration parameters. The key function of GA is the quantity estimation of streaming data through SpaceFibre. To the best of our knowledge, there is no such methods for SpaceFibre networks. It is for this reason that the mathematical method of quantity estimation has been developed and presented in the paper. The math model of streaming over SpaceFibre was also developed for this method. It is based on Markovian chain. Examples of calculations are given. The proposed method could be used for SpaceWire networks with STP-ISS-14 protocol.