Realtime network management support systems at NTT

This paper describes realtime network management support systems which have been developed forntt’s telephone network. In particular, the advanced traffic observation and management information collecting system referred to as Atomics and the traffic congestion control system referred to astcs are presented. The purpose of the development, concept, functions and capabilities of each system are explained. Examples of powerful realtime network management supported by Atomics andTSC are also presented.     

时间依赖的混合型网络的分布式路由协议

提出了时间依赖的混合型网络模型(HTDN 模型),有效地描述了网络中链路权值随时间变化的特性,并且网络中的节点可以采用不同的等待策略;并给出了 HTDN 模型的路径优化理论。在此基础上设计了有效的分布式路由协议 DMDRP,能计算出 HTDN 模型中所有节点对之间的最短延时路径,并证明了协议的正确性。最后通过仿真试验,给出了 DMDRP 协议与传统路由方案的性能对比分析。     

Saturation routing network limits

Saturation routing means a flooding of a network with messages which search for a particular subscriber's number without regard to where that subscriber is located in the network. Saturation routing, often thought of as inappropriate in a communication network, can be a useful routing scheme with the use of state-of-the-art design. In this paper, consideration will be spent on the kinds of networks in which saturation routing is applicable, and how it compares with other routing systems. The functional designs of saturation routing will be combined with the appropriate variables to create a mathematical model for performing of saturation routing in a network. The following are some of the variables: i) processor rate; ii) transmission data rate; iii) hierarchy; iv) queuing delays; v) traffic; vi) message size. The paper will be concluded with an example of a realistic network using saturation routing.     

Load balance in hierarchical routing network

In this article, the problem of load balance in hierarchical routing network is studied. Since conventional shortest path first (SPF) algorithm over aggregated topology in hierarchical routing network may result in worse routing performance, a traffic sharing path selection algorithm and a variable weight scheme are put forward for hierarchical routing network, which can equilibrate the utilities of link resources and reduce the blocking probability of connections with the improvement on survivability. Simulations are conducted to evaluate proposed variable weight and traffics balance (VWTB) algorithm, which combines traffic sharing and variable weight. From the simulation results, it can be found that the proposed VWTB algorithm can balance the traffics and equilibrate the utilities of link resources significantly.     

Minimum delay routing in stochastic network

The authors consider the problem of traveling with least expected delay in networks whose link delays change probabilistically according to Markov chains. This is a typical routing problem in dynamic computer communication networks. Several optimization problems, posed on infinite and finite horizons, are formulated, and they are considered with and without using memory in the decision-making process. It is proved that all these problems are, in general, intractable. However, for networks with nodal stochastic delays, a simple polynomial optimal solution is presented. This is typical of high-speed networks, in which the dominant delays are incurred by the nodes. For more general networks, a tractable ∈-optimal solution is presented     

Dynamic routing in the multiple carrier international network

Presents an overview of the efforts of the 13 participating carriers that comprise the Worldwide Intelligent Network (WIN) Dynamic Routing Group to introduce dynamic routing internationally. The authors propose that the introduction of dynamic routing could be accomplished in stages, starting with the deployment of flexible overflow routing for bilateral networks. Then the authors examine performance feasibility issues associated with multiple carrier transit routing and analyze data items that need to be exchanged by international carriers to realize dynamic traffic control. They also review major conclusions that can be made based on the results of the first WIN dynamic routing trials. Finally, they review a proposal for standardization of certain signaling messages that enables the realization of real-time state-dependent routing in a multiple carrier environment     

计算机网络路由探究综述

随着科学技术的不断发展与进步,计算机网络的功能越来越多,使得网络路由的发展面临着更多的挑战。目前,计算路由的方式有很多种,目的就是为了使其运行满足路径传递信息的需求,不仅提高了服务质量,还使网络资源的利用率得以提高。     

Active intersession network coding-aware routing

Coding-aware routing can create more coding opportunities by selecting the proper routing path. The main challenge in exploiting network coding is how to develop an effective network coding conditions. In this paper, we develop the active intersession network coding (AINC) which can create more intersession network coding opportunities than the general intersession network coding (GINC) by actively exploiting the redundancy information in the network with the deliberately built bridge links. With the aim to find multiple candidate parallel paths for each unicast, the conventional Bellman–Ford algorithm is enhanced. Built on AINC and the enhanced Bellman-Ford algorithm, we propose the active intersession network coding-aware routing (AINC-AR) scheme for the wireless network which supports multiple unicasts. The basic idea of AINC-AR is to select the path from all available candidate ones by jointly considering the effects of network coding gains and path costs on the overall network costs, so as to minimize the total network costs. Simulations are conducted to demonstrate the advantages of AINC-AR over GINC-AR and the conventional routing scheme without considering network coding.     

应用单纯形算法解决动态路由问题

探讨了如何在长途电话交换网中应用单纯形算法解决动态路由问题，并介绍了算法运行情况和运行结果。单纯形算法能够在很短的时间内得到质量很好的全局优化的路由方案。     

Bidirectional shuffle-exchange network and tag-based routing algorithm

We enhance the general shuffle-exchange network (GSEN) with bidirectional links. For bidirectional links, the bidirectional GSEN can be divided into two dependent networks, forward network and backward network. Based on the idea of inversely using the forward tag, we propose a tag-based routing algorithm for the backward network, so as to reduce the computation of the shuffle-exchange operation.     

Traffic routing in a hybrid analog-digital network

This paper presents the results of a study carried out at CNET on the gradual digitalization of a large telecommunication network, SATINcomputes the traffic routing and the trunk groups in the hierarchical switched networks and minimizes its global cost. An experimental network comprising approximately 770 centres, where the percentage of digital switching centres is increased from 0 % up to 100 % is used. The paper points out the most important effects of digitalization and analyzes the grounds for these effects.     

基于激光链路的卫星光网络路由算法

结合卫星网络拓扑结构的时变性特点,建立了时变卫星光网络模型,对网络模型进行离散化,形成一系列相对固定的网络拓扑结构.通过优化传统的Dijkstra算法,提出了NNSP算法,把它引入到卫星光网络副载波/光波的双层路由算法中,最后仿真比较了网络延时,进一步证明卫星光网络路由算法的可行性.     

车载网络GPSR路由改进算法

GPSR路由协议在车载网络的应用中,因使用贪心算法而采用边缘节点进行数据转发,在转发过程中容易造成数据包丢失、服务质量低下等问题。文中针对原GPSR协议在数据转发模式上的缺陷,提出选取众多车载网节点中移动速度缓慢的节点作为中继节点,以减小选取移动速度过快的节点作为中继节点出现的概率。通过仿真对比原协议和改进后协议前后端到端延时、不同移动速度下的数据包接收的成功率、抖动率以及吞吐量等方面的性能,实验结果表明改进算法提高了协议的工作效率,优于原GPSR协议,更加符合车载网络的应用。     

传输网络第三条路由的设备解决方案

本文介绍了传输网络在某一节点建设第三条光缆路由时的设备解决方案.同时对OLP技术、OLP各种实现方式及工程中应注意的事项进行论述.对于利用交叉单元实现第三路由的接入,本文着重阐述了SDH网络及OTN网络光、电层面交叉技术的实现方式和局限,并最终提出两种技术的应用思路.     

Stochastic analysis of network coding in epidemic routing

Epidemic routing has been proposed to reduce the data transmission delay in disruption tolerant wireless networks, in which data can be replicated along multiple opportunistic paths as different nodes move within each other's communication range. With the advent of network coding, it is intuitive that data can not only be replicated, but also coded, when the transmission opportunity arises. However, will opportunistic communication with network coding perform any better than simple replications? In this paper, we present a stochastic analytical framework to study the performance of epidemic routing using network coding in opportunistic networks, as compared to the use of replication. We analytically show that network coding is superior when bandwidth and node buffers are limited, reflecting more realistic scenarios. Our analytical study is able to provide further insights towards future designs of efficient data communication protocols using network coding. As an example, we propose a priority based coding protocol, with which the destination can decode a high priority subset of the data much earlier than it can decode any data without the use of priorities. The correctness of our analytical results has also been confirmed by our extensive simulations.     

Ad hoc网络中基于数据流的QoS路由协议

已有ad hoc网络中的QoS路由都是基于目的地址的选路并预留资源,当源节点针对同一个目的节点先后建立两个或者多个实时业务流的时候,将导致几个数据流争用资源,使得几个流的QoS都无法得到保证。针对这个问题,文章提出了基于流的QoS路由机制,并且进行了仿真分析,仿真结果表明这种机制能够解决这个问题,使QoS得到保证。     

Traffic routing in the Warsaw metropolitan network: a deploymentstrategy

The Warsaw metropolitan network is undergoing a radical architectural and technological transformation. The transformation, forced by the large unrealized demand for telephone stations, and structural traffic bottlenecks, is based on the installation of eight digital transit switches of high capacity. The so-formed upper transit layer gives an opportunity for the deployment of an efficient traffic routing system, for carrying the growing traffic well beyond the year 2000 without additional investments. A step-wise strategy is presented far the deployment of a modern traffic routing system in the Warsaw network, adapted to, and taking advantage of the fast transformation of the network. The choice of the strategy is based on a case study of the traffic handling efficiency of various routing systems in a model of the Warsaw metropolitan network     

浅析IPv6网络地址分配与路由技术

在IPv4校园网络基础上快速部署IPv6网络。对IPv6的地址分配技术、路由技术进行具体分析研究,并结合Cisco和H3C两大品牌设备,给出配置方法。借助于认证系统的相关功能向客户机系统安装IPv6协议,并对IPv6地址的使用情况进行统计分析。