Research On Multi-service Scheduling Mechanism Of FC-AE-1553 Multi-stage Network

Fiber Channel-Avionics Environment(FC-AE)technology,which is mainly used for data communication between devices in aviation environment,is one of the key technologies to the field of aviation communication,because it can meet the requirements of bandwidth,reliability and real-time in aeronautical communication applications.In the FC-AE-1553 switching network,multiple data exchanges of services can be transmitted in parallel at the same time to meet the network bandwidth requirements as the traffic volume of services is increasing.Due to the limited storage resources,circuit scale and power consumption of avionic device,the maximum number of FC-AE-1553 exchanges that can be transmitted in parallel at the same time is limited.To design an effective parallel scheduling mechanism to achieve higher network throughput under the condition that the maximum number of parallel transmitting exchanges is limited is difficult.In addition,with the increase of remote terminals,controllers,and payload terminals in aerospace scenario,the number of services increases and the terminals present group distribution in different locations.The network structure needs to be extended to FC-AE-1553 multi-stage switching network.Exchanges exist not only inside a switching domain but also between switching domains.The service scheduling across the switching domain needs to solve multiple-link conflicts while doing bandwidth allocation.In this paper,the research and design of multi-service scheduling mechanism is carried out in both single-stage FC-AE-1553 network under the scenario where the maximum parallel scheduling number of exchanges is limited and FC-AE-1553 multi-stage switching network.The main contents and research results are as follows:1.In FC-AE-1553 first-stage network,in order to increase the network throughput where the maximum number of parallel transmitting exchanges is limited,this paper designed a fixed-length slot scheduling(SS)dynamic bandwidth allocation(DBA)mechanism,which performed better than the Limited Exchanges-Porportional Allocation(LE-PA)mechanism limiting the number of scheduled exchanges in a DBA period or the complex scheduling algorithm monitoring the number of exchanges at any moment.The proposed method can simply satisfy the limit condition on maximum number of parallel scheduling exchanges by scheduling exchanges of nodes whose number equals to the maximum number of parallel scheduling exchanges.Thus SS algorithm improved the network throughput by scheduling far more exchanges than LE-PA mechanism in a DBA cycle.The simulation results showed that the SS mechanism improved the network throughput by 42.4%,41.1%and 67.9%in the 32-node,20-node and 10-node networks respectively,compared with the LE-PA mechanism.When DBA period is lms,compared with the LE-PA mechanism,the SS mechanism reduced the average delay of common burst service from 88.1ms,38.9ms and 9.6ms to 7.1ms,3.4ms and 1.2ms in 32-node,20-node and 10-node networks,respectively.2.To solve the bandwidth allocation problem of data exchanges where there are conflicts among links between switching networks in FC-AE-1553 multi-stage network,considering that the overall performance of the mullti-stage switching network depends on the bandwidth of the link interconnecting networks when the bandwidth of each link of the entire network is the same,this paper designed a multi-service scheduling algorithm for centralized control multi-stage network which allocated bandwidth for exchanges between switching networks at first.It can distinguish exchanges within the switching network or between switching networks.After allocating the bandwidth of links between switching domains and the links inside switching domains for exchanges across switching networks,the exchanges between nodes inside one switching network are allocated bandwidth.This mechanism can reduce the service delay between switching networks and achieve higher network throughput.3.Based on OPNET software,the FC-AE-1553 multi-stage switching network simulation platform was built.The platform implemented configurability of nodes,link forrmat,protocol frame forrmat,service data source,service scheduling mechanism and DBA cycle.The platform is scalable with network topology,service source type,and service scheduling mechanism type.The proposed multi-service scheduling mechanism of the centralized control multi-stage network was then simulated and verified on the platform.The simulation results showed that when DBA period was set to 5ms and the intra-network/inter-network traffic flow ratio of common burst traffic was set to 40:1,the network throughput can reach 100.2Gbps.The delay jitter of the periodic traffic was 0.The average delay for time constraint burst traffic was 6.0us and the maximum delay was 40.0us.