电力系统网络实时通信中的质量控制

针对目前电力系统计算机网络上大量实时数据的出现和传统通信网络的不足，提出了网络通信中服务质量机制的概念和策略。在分析RTP／RTCP协议的基础上，提出了一个实时通信系统的客户／服务系统体系结构。在该客户／服务系统中，提出了点对点通信和多播通信环境中的服务质量评估与自适应速率控制机制的策略及有关实验数据，结构表明该系统可以在变化的网络环境中实现一定的传输质量保障。     

Efficient Internet Multicast Routing Using Anycast Path Selection

A novel efficient and dynamic multicast routing protocol based on anycast routing techniques is presented. The contributions of the protocol differ from well-known shared-tree systems in two aspects: (1) Off-tree anycast routing: The nodes in the shared tree are formed into a virtual anycast group and multicast sources use anycast routing to select a better path from the source to one router in the group to achieve short delay and fault-tolerance. (2) On-tree dynamic routing: The shared-tree approach is extended with capability of alternative path selections. If a node becomes absent from the shared tree, some predefined backup path(s) is (are) used to bypass the node and enable dynamic multicast routing to continue. The protocol requires only the routers near the faulty node to be reconfigured, thus reducing the runtime overhead as compared with global reconfiguration. The simulation data demonstrates the efficiency of our routing protocol.     

A Delay-Constrained Least-Cost Multicast Routing Heuristic for Dynamic Multicast Groups

Many new multimedia applications involve dynamic multiple participants, have stringent end-to-end delay requirement and consume large amount of network resources. In this paper, we propose a new dynamic delay-constrained least-cost multicast routing algorithm (DDCLCMR) to support these applications. When group membership changes, the existing multicast tree is perturbed as little as possible. Simulation results show that DDCLCMR performs very well in terms of cost for both, static and dynamic multicast groups, when compared to the best multicast algorithms known. Our evaluation of the cost performance of the algorithms showed that DDCLCMR is always within 10% from BSMA which has the best cost performance among all the proposed delay-constrained static multicast heuristics, while NAIVE, the well-known dynamic multicast routing algorithm, is up to 70% worse than BSMA in some cases.     

Study of General Icomplete Star Interconnection Networks

The star networks,which were originally proposed by Akers and Harel,have suffered from a rigorous restriction on the number of nodes.The general incomplete star networks(GISN) are proposed in this paper to relieve this restriction.An efficient labeling scheme for GISN is given,and routing and broadcasting algorithms are also presented for GIS.The communication diameter of GISN is shown to be bounded by 4n-7.The proposed single node broadcasting algorithm is optimal with respect to time complexity O(nlog2n).     

Efficient Non-Repudiation Multicast Source Authentication Schemes

In secure multicast communication,Packet source authentication is a bottleneck problem due to the dynamic property of the multicast group,unreliability of data transmission and the large number of data packets.This paper proposes a novel authentication scheme called B-MSAS(Balance Multicast Source Authentication Scheme)that can be used to solve this problem,in which a new message authentication technique is introduced.This scheme dramatically reduces the signature size overhead and raises the signature rate.It provides thenon-repudiation service,high loss resistance,and can easily be scaled up to potentially millions of receivers,and hence has a sweeping applicability,It should have applications to many practical problems.     

LE-SBCC: Loss-Event Oriented Source-Based Multicast Congestion Control

Congestion control is an important building block of a Quality of Service (QoS) system for multicast-based multimedia services and applications on the World Wide Web. We propose an end-to-end single-rate source-based multicast congestion control scheme (LE-SBCC) for reliable or unreliable multicast transport protocols. It addresses all the pieces of the single-rate multicast congestion control problem including drop-to-zero issues, TCP friendliness and RTT estimation. The scheme design consists of a cascaded set of filters and a rate-based additive-increase multiplicative-decrease (AIMD) module. These filters together transform the multicast tree to appear like a unicast path for the purposes of congestion control. Unlike TCP, the scheme is not self-clocked but acts upon a stream of loss indications (LIs) from receivers. These LIs are filtered to get a stream of loss events (LEs) (S. Floyd et al., in SIGCOMM 2000, Aug. 2000) (at most one per RTT per receiver). This LE stream is further filtered to extract the maximum LEs from any one receiver. Then the scheme effects at most one rate-reduction per round trip time (RTT). A range of results (simulation and experimental) is presented and compared against the mathematical model of the scheme components. Furthermore, we have successfully adapted TFRC (Op. cit) to our scheme, which is important to multimedia services desiring relatively stable rates over short time scales.     

基于蚂蚁算法的QoS路由调度方法

为了有效地解决QoS受限路由问题,本文提出了一种新颖的具有全局优化能力的蚂蚁算法,它是基于蚂蚁具有找到蚁巢与食物之间的最短路径原理工作的。 仿真实验表明,该方法能够有效地解决QoS受限路由问题。     

On the fault-tolerant routing in distributed loop networks

Based on their "Theorem 2", an O(δ)-time algorithm of searching for the shortest path between each pair of nodes in a double loop network was proposed by K.Mukhopadyaya, et al.(1995). While, unfortunately, it will be proved that both "Theorem 2" and its proof are in error. A new and more faster O(△)-time, △≤δ, algorithm will be presented in this paper.     

基于IP组播的告知服务器的以太网实现

同步协作是计算机支持的协同工作研究的一个重要领域,告知服务器为群组的同步协作提供了感知的实现技术,告知服务要求有效地向群组用户投递事件消息。ＩＰ组播技术是 服务 通讯技术,被广泛用于视音频群组通信,但目前许多告知服务器实现仍然采用点对 通信技术,在多媒体远程协作系统中,直接利用ＩＰ组播技术实现了可靠的告知服务,并初步分析了ＩＰ组播在以太网络上的实现方式和实现可靠笥的条件。     

一种QoS保证的路由算法

首先定义了业务连接资源消耗函数和带宽碎片影响函数,以此作为ＱｏＳ路由策略的选路优化函在后提出一种综合的考虑业务的连接特性和网络资源优化利用ＱｏＳ路由算法,最后给出仿真结果。