Organizing message transmission in AFDX networks

In this paper, a problem of periodical message transmission in the onboard networks based on the Avionics Full Duplex Ethernet (AFDX) standard is formalized and an algorithm for solving this problem is proposed. The algorithm combines the greedy approach with the limited exhaustive search and consists of several procedures to solve the problem step by step with respect to the constraints imposed. The results of the experimental research aimed at investigating the effectiveness of the proposed algorithm are presented.     

On virtual private networks security design issues

The concept of virtual private networks (VPNs) provides an economical and efficient solution on communicating private information securely over public network infrastructure.In this paper, we discuss two issues on the design of VPN. We first propose the VPN services, the mandatory VPN operations for each VPN service and the design on VPN protocol stack.Afterwards, we propose a list of protocol modules to be used to support the VPN operations and co-relate the mandatory VPN operations to the appropriate VPN protocols. We then propose the design of VPN software that provides guarantees on security, connectivity and quality of service. We also discuss the message processing sequence by the VPN software.     

基于策略的AFDX网络管理的设计与分析

为了减小网络管理流量对航电系统正常通信任务的影响,并缓解航空电子管理任务的交叉耦合问题,提出一种基于策略的分布式航空电子网络管理模型,拟采用分层管理方式,在策略指引下对航空电子全双工交换式以太网( avionics full duplex switched Ethernet,AFDX)进行针对性的监控,以有限的宿主计算资源进行及时的信息处理.给出一个AFDX网络互连拓扑的案例,对于常规和基于策略的网络管理体系的复杂度进行评估,并在一套设定的虚拟链路(VL)流量配置下,比较两种体系下的网络管理流量对VL通信任务实时性的影响.网络演算和仿真结果表明了该模型具有可行性和有效性.     

Holistic schedulability analysis for multipacket messages in AFDX networks

The ARINC-664, Part 7 (AFDX) standard defines a communication network based on Ethernet and the UDP/IP protocols. Contrary to general-purpose Ethernet, the timing behavior in AFDX is deterministic due to the use of special network switches and end systems with static routing tables and traffic policing at the sending end through mechanisms called virtual links. Even though the latencies in this network are bounded, there are scheduling and contention effects that need to be analyzed. In this paper we develop a response-time analysis for multipacket messages transmitted through an AFDX network including the scheduling of the virtual links and sub-virtual links, and also the contention in the end systems and in the switches. This analysis allows us to obtain worst-case latencies and output jitter for the network messages with a precise modeling of the sending and receiving ends. These results can be integrated in a holistic approach with the response time analysis of the threads in the processing nodes to obtain end-to-end response times in heterogeneous distributed systems.     

Optimal design of a star-LAN using neural networks

Optimal design of a Star-LAN includes a few important and difficult sub-problems. An optimal HUB allocation problem is one of the sub-problems. Neural networks based on the Boltzmann machine are suitable for solving such problems. In this paper, we apply the Boltzmann Machine Neural Networks(BMNN) to optimal HUB allocation problems on a Star-LAN computer networks. We also show some numerical experiments to demonstrate performances on solving the problems.     

Kinematic analysis via virtual links

An exact method is presented whereby kinematic analysis of plane mechanisms is performed with the aid of one or more flexible virtual links. The method enables the analysis of a broad class of mechanisms. The use of the virtual link is illustrated by several examples.     

A new algorithm for virtual path network design in ATM networks

Virtual paths (VPs) in an ATM network form a logical network, called VP network (VPN), over the underlying physical network. VPN allows flexible management of network resources and hence its design is an important issue in designing an ATM network. In this paper, we consider the VPN design problem which is formulated as an optimization problem with the objective of minimizing the switching and transmission cost, and control and management cost. We present here, a two-phase heuristic solution for designing a good VPN for a given traffic demand. The first phase is a routing phase in which a route is found between every node pair in the network. In the second phase, paths are selected as VPs using the set of routes generated in the routing phase. A path is selected as a VP so as to minimize the following parameters: (i) the total number of VPs configured; (ii) the number of VPs carried by a link (load); and (iii) the VP hopcount, the number of VPs that are concatenated to form a virtual channel (VC). We study the performance of the proposed algorithm through extensive simulation on various networks. The results show that the VPN generated by the proposed algorithm is good in minimizing the number of VPs configured, the load on a link, and the VP hopcount. The comparison of the results obtained by the proposed algorithm and that of Ahn et al. [Virtual path layout design in ATM networks, in: Proceedings of IEEE INFCOM’94, Toronto, Ontario, Canada, 1994, pp. 192–200] shows that our algorithm performs better.