A Routing Algorithm for Computer Communication Networks

A new algorithm for routing data packets in networks of computers connected by communication links is given. It is shown that considerable savings in required storage capacity can be obtained by adopting the proposed algorithm as compared to earlier known algorithms.     

计算机通信网动态路由问题的稳定性研究

本文提出了计算机通信网动态路由的稳定性问题，将现代控制理论引人到计算机通信网理论领域，从系统控制的角度建立了多业务流多链路网络系统信息包从源节点到目的节点传输的全过程和网络节点分流的状态空间模型，从不同的侧面描述、考察了路由选择的随机动态特性；在此基础上，应用李亚普诺夫系统稳定的方法，提出了多个传输链路的利用率函数Ｇ（·）和节点分流矩阵Ｒｄ的稳定性限制与条件，最后给出了一个例子和结论。     

The Join-Biased-Queue Rule and Its Application to Routing in Computer Communication Networks

A routing rule similar in nature to delta-routing [8] is studied in this paper. The approach is to superimpose, local adaptivity on top of a fixed traffic flow distribution. The fixed flow distribution we choose is obtained from the best stochastic (BS) rule [3]. The adaptive part is called the join-biased-queue (JBQ) rule. The resultant JBQ-BS rule is analyzed on small networks and is shown to provide 10-27 percent delay improvement over the BS rule.     

Bottleneck Routing Games in Communication Networks

We consider routing games where the performance of each user is dictated by the worst (bottleneck) element it employs. We are given a network, finitely many (selfish) users, each associated with a positive flow demand, and a load-dependent performance function for each network element; the social (i.e., system) objective is to optimize the performance of the worst element in the network (i.e., the network bottleneck). Although we show that such "bottleneck" routing games appear in a variety of practical scenarios, they have not been considered yet. Accordingly, we study their properties, considering two routing scenarios, namely when a user can split its traffic over more than one path (splittable bottleneck game) and when it cannot (unsplittable bottleneck game). First, we prove that, for both splittable and unsplittable bottleneck games, there is a (not necessarily unique) Nash equilibrium. Then, we consider the rate of convergence to a Nash equilibrium in each game. Finally, we investigate the efficiency of the Nash equilibria in both games with respect to the social optimum; specifically, while for both games we show that the price of anarchy is unbounded, we identify for each game conditions under which Nash equilibria are socially optimal.     

Approximations of Queue Dynamics and Their Application to Adaptive Routing in Computer Communication Networks

Various adaptive algorithms have been proposed for routing, flow and congestion control in packet-switched computer communication networks. In most of them, information on queue lengths, or equivalently, time delays, at various points in the network is required for proper adaptation. Since up-to-date information is not always available, these quantities must be estimated based on prior information. This paper presents approximations for the dynamic behavior of theM/M/1queue which is used to yield the desired estimates of queue lengths. Based on the assumption of finite (but arbitrarily large) storage, a closed form expression for the evolution in time of the queue length distribution is obtained. From this expression various approximations for estimated queue length are extracted. A simple expression for the "relaxation time" of the queue is also deduced as a function of utilization factor and service time. The approximations are applied to a simple adaptive routing example in which packets are routed along the transmission path having the shortest estimated queue, based on delayed information.     

Routing to Multiple Destinations in Computer Networks

Algorithms for effectively routing messages from a source to multiple destination nodes in a store-and-forward computer network are studied. The focus is on minimizing the network cost (NC), which is the sum of weights of the links in the routing path. Several heuristic algorithms are studied for finding the NC minimum path (which is an NP-complete problem). Among them are variations of a minimum spanning tree (MST) heuristic and heuristics for the traveling salesman problem, both of which use global network information. Another set of heuristics examined are based on using only the shortest paths to the destinations. While the MST algorithm has the best worst case performance among all algorithms, a detailed, empirical study of the "average" performance of the algorithms on typical, randomly chosen networks reveals that simpler heuristics are almost as effective. The NC cost measure is also compared to the destination cost (DC), which is the sum of weights of the shortest path distances to all destinations. A scheme of algorithms is given which trades off between NC and DC.     

卫星网络路由技术概述

卫星网络不仅能提供全球无缝覆盖,具有连续的高带宽性能,而且还支持灵活、可扩展的网络配置.文中阐述了具有星间链路的卫星网络在空间通信中的重要地位及其路由算法应当具有通用、简洁和可靠等特点.从单层、两层与多层卫星网络路由三方面综述了多种路由算法,并对其进行详细的分析和比较,最后指明了进一步的研究方向.     

计算机通信网中路由选择和容量分配问题的遗传算法求解

计算机通信网中，对路由选择和容量分配问题进行综合优化设计时的数学模型，是一个多约束条件的非线性０－１规划。本文以遗传算法的基本思想为基础，设计了一个求解该问题的遗传寻优算法，对计算机通信网优化设计实例的计算表明，这一方法能够迅速求出问题的全局近似最优解，并具有高的计算精确度。     

移动通信中的天线技术

介绍了移动通信中天线的新技术．阐述了全向高增益天线、多频段天线、极化分集天线和智能天线的实现技术以及在移动通信中的应用。     

战术通信网中按需路由协议的仿真研究

战术通信网是现代信息战中产生的一个重要的战场信息传输网络,其中路由协议的选择对于网络能否成功构建至关重要。在此研究了战术通信网按需路由协议中的AODV协议和DSR协议,对两种协议进行详细的分析比较,并通过OPNET仿真工具对AODV与DSR协议在不同场景下的路由开销、网络延迟和丢包率进行仿真分析,指出了两种协议各自的优势和特点,为两种路由协议在无线传播环境下的应用提供了有效的依据。     

IP网络服务质量保证技术

现有的IP网络本身没有特别考虑对业务服务质量的保证技术,无法满足综合业务的应用。几年来,业界提出了一些针对IP网络的服务质量保证方法,但是并没有真正在现有网络中普及应用。随着下一代网络的提出,网络服务质量保证技术已经列为其核心技术,只有该技术得到解决,基于IP的下一代网络才能够满足电信级网络的要求。简要分析了服务质量的要素,梳理了服务质量保证的几个关键技术,并对这些技术的原理和特点进行了简要分析。     

Multipath Routing Techniques in Wireless Sensor Networks: A Survey

Multipath routing is an efficient technique to route data in wireless sensor networks (WSNs) because it can provide reliability, security and load balance, which are especially critical in the resource constrained system such as WSNs. In this paper we provide a survey of the state-of-the-art of proposed multipath routing protocols for WSNs, which are classified into three categories, infrastructure based, non-infrastructure based and coding based, based on the special techniques used in building multiple paths and delivering sensing data. For each category, we study the design of protocols, analyze the tradeoff of each design, and overview several representing protocols. In addition, we give a summery of design goals, challenges, and evaluation metrics for multipath routing protocols in resource constrained systems in general.     

A Genetic Algorithm for Routing in Packet—Switched Communication Networks

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通信网时间同步技术研究

随着通信及计算机网络的发展,越来越多的设备及应用对时间同步提出了比较高的要求。本文首先对时间同步的概念及通信网时间同步的必要性做了简要的介绍,然后对几种主要的时间传送技术和组网结构进行了研究讨论,最后介绍了时间同步技术在国内外通信网中的应用情况。     

Query Localization Techniques for On-Demand Routing Protocols in Ad Hoc Networks

Mobile ad hoc networks are characterized by multi-hop wireless links, absence of any cellular infrastructure, and frequent host mobility. Design of efficient routing protocols in such networks is a challenging issue. A class of routing protocols called on-demand protocols has recently found attention because of their low routing overhead. We propose a technique that can reduce the routing overhead even further. The on-demand protocols depend on query floods to discover routes whenever a new route is needed. Our technique utilizes prior routing histories to localize the query flood to a limited region of the network. Simulation results demonstrate excellent reduction of routing overheads with this mechanism. This also contributes to a reduced level of network congestion and better end-to-end delay performance of data packets.     

Routing in Wireless Sensor Networks Using Optimization Techniques: A Survey

Wireless Personal Communications - Over the past few decades, one of the important advancements in wireless communication is low cost and limited power devices known as wireless sensor networks...     

WDM在SDH传输网中应用的技术问题

波分复用技术 ( WDM)在中国电信同步数字体系 SDH光传输网中的广泛运用 ,必将极大地满足宽带长途传输和接入的需求。通过分析波分复用技术相对于时分复用技术( TDM)的优越性及其在 SDH传输网中的应用 ,讨论了 SDH网络中使用 WDM的关键技术 ,并探讨了 WDM与 SDH网络管理一体化的技术方案和优势     

天地一体化网络中卫星通信港控制架构与路由技术研究

通过分析天地一体化骨干网络发展趋势及其约束条件,提出了卫星通信港的概念,阐述了其基本特点,并分析了目前面临的诸多挑战。针对卫星通信港的管理控制问题,提出了软件定义卫星通信港的体系架构,通过对地面网络、卫星网络等不同子网进行分层控制,承载海陆空各种类型节点的连接请求,最终满足不同用户的信息传输需求;同时,提出了以卫星通信港为核心骨干网的天地一体化网络路由策略,为提高网络的运行效率和承载能力提供了新的解决思路。     

一种无线传感器网络自适应协同通信路由协议

无线传感器网络的重要应用特性是具有感测信息的传感节点形成一个自适应本地网络,由中心节点执行不同的协作信息处理任务。该文基于互信息量分析了不同中心节点选择机制的开销性能,证明了基于扩散计算的选择机制的开销有效性;提出一种自适应协同通信路由协议(ACCRP)：节点以分布式的方式选择中心节点并建立传输路径;分析讨论了ACCRP的性能参数;并通过实验验证了ACCRP是能源有效的、可扩展的自适应路由协议。