分组传送网的环保护和生存机制

在保护和恢复机制方面,分组传送网络面临运行操作与维护（OAM）检测性能、网络资源优化、资源分配死锁、资源部署阻塞等众多挑战。传统的保护和恢复机制已不能满足分组传送网络的需求。为了提高分组传送网络保护恢复性能、网络资源的利用率、业务恢复可能性,减少业务部署的阻塞率,文章对交迭段保护机制、预规划多环、冲突避免算法、延时恢复算法等新型保护恢复机制进行了研究,得出观点：保护和恢复机制合理,由时分复用向分组承载的平滑演进、网络融合和网络全业务化才有可能。     

SDH网络的保护和恢复

文章首先介绍了网络生存性的重要意义及业务恢复时间的要求,分析了ＳＤＨ网保护方式的分类与特点,针对各种常用自愈环结构进行了分析比较,并讨论了ＳＤＨ网的恢复问题,特别是网络恢复控制方法、网络恢复级别以及各种保护／恢复方法的比较和协调。     

网络虚拟化环境下的故障管理

网络虚拟化是未来网络的重要特征和演进方向.及时准确地定位网络故障并迅速隔离和恢复故障对于网络虚拟化环境下网络的健壮性、生存性和可管理性均具有重要的意义.然而,针对虚拟网络环境中网络规模扩大、网络的多层次性和不确定性等特性,传统的故障管理机制具有一定的局限性,需要基于网络虚拟化环境的特点研究其故障管理机制.分析了网络虚拟化环境下故障管理流程,并基于流程中的3个重要环节分析了网络虚拟化环境下故障探测、故障定位和故障恢复这3个方向的研究现状和趋势.     

SDH多环网络情况下自愈问题的研究

以往考虑SDH网的恢复时，即使实际网络由多个SDH环构成，也以单环恢复机制进行恢复。在此我们讨论了从多环网的角度考虑SDH网恢复的必要性和现实意义，并针对这一问题，提出了相应的解决方案。     

中兴ZXOXC原理及应用

1　 OXC在 OTN中的定位OXC(光交叉连接设备 )是一种兼有复用、配线、保护 /恢复、监控和网管的多功能 OTN(光传送网 )传输设备。 OADM可以看成 OXC结构的功能简化设备。对于一般传输网络而言 ,OXC并不是一种必须的网元 (例如网络拓扑主要为环或链 ,而且其保护和恢复方案也以环网为基础时 ) ,其必要性和重要性取决于网络规模、规划者的保护 /恢复策略和对网络可靠性的要求等各方面因素。如果运营商为了提供网络必需的灵活配置能力和以较小的冗余代价 (含线路和设备 )使网络具备必要的保护 /恢复功能 ,则必须在网络中配置 OXC设备。…     

SDH倒换故障处理实例

基于各种不同保护机理的SDH自愈环大大提高了网络的生存能力,使之在出现故障的情况下,无需人为干预,就能在极短的时间内从失效的故障状态自动恢复传输所携带的业务,使网络具备一种可替代的传输路由.但是自愈网络也有失去保护的时候,当保护倒换协议出现异常,传输业务就会中断.本文就SDH网络MSP(复用段保护)环倒换失败进行原因分析和处理.     

基于P环的恢复机制在WDM网状网中的应用

目前波分复用(WDM)网状网中所采用的恢复机制的恢复速度较慢,不能满足某些业务的需求。利用空闲容量建立的p环(pmcmtfigured cycles)具有环形网的速度和网状网的容量效率。它的操作方法简单,使用灵活,可以应用于WDM网和IP网等不同的网络。本文详细介绍了p环的基本原理、构造过程及优化方法或讨论了多故障的情形,并对一些新的研究方向作了评述,可供网络设计者参考。     

无线传输技术在通信机房动环监测中的应用

现阶段，通信机房动环监测能以多种方式进行数据传输，其中无线网络传输技术主要包括4G、5G等，实现了多种环境下的动环监测。为了能在通信网络中断的情况下正常使用网络，现阶段动环监测机房中仍有传统有线网络存在，有助于避免影响正常的传输工作，进一步提高通信机房动环监测的可靠性和故障处理效率。文中对通信机房动环监控系统的建立、开发与应用进行了分析，在此基础上，提出了通信机房动环监测中的无线传输应用关键技术，希望能促进通信机房动环监测的发展，为通信工作者提供参考。     

MSC POOL被叫恢复异常情况解决策略

在实施MSC-POOL之后,许多参数设置与组POOL前、双归属时代有较大区别,网络架构有较大变化,导致网络运行维护中出现许多新情况。本文针对网络运营过程中OFI的0局点冗余数据、SCCP环回标识设置冲突导致被叫恢复异常情况进行分析,并提出解决策略。     

能耗均衡的无线传感网络不等环分层路由算法

针对无线传感器网络(Wireless Sensor Network,WSN)中邻近汇聚节点(sink)的传感节点负荷和能耗过载问题,基于整体网络能耗平衡目标,提出一种不等环的次优分层网络路由。在均匀分布的传感节点环境中,以sink为中心,按照拓扑距离进行分环多跳路由,理论推导了不等环半径,并考虑单跳能耗。实验分析仿真结果表明,该路由分层模型延长了网络生存周期,提高了节点利用效率,且达到网络内大部分节点能耗均衡的目标。     

一种低成本RPR实现方案

文章介绍了一种低成本RPR实现方案.该方案由双光纤环构成,并能在双环上同时传输数据;具有业务接入灵活、空间复用、支持QoS、保护恢复迅速和易于管理等特点.该方案既有效利用了RPR的特点,又针对特定的应用环境作了简化和改进,是一种很有竞争力的城域专用网解决方案.     

Combinatorial design of congestion-free networks

This paper presents a new design methodology and tools to construct a packet switched network with bursty data sources. This network design combines two important properties for arbitrary traffic pattern: (1) the aggregate throughput is scalable and (2) there is no packet loss within the subnet. More specifically, given a bounded number of ports in every switching node, the design is based on the construction of multiple virtual rings under the following constraints: (1) the virtual rings are pairwise edge-disjoint and (2) there is at least one virtual ring between any pair of nodes. The target topology is obtained from the edge union of the multiple virtual rings. The two constraints ensure no loss due to congestion inside a network with arbitrary traffic pattern and that packets will reach (or converge) their destinations. The virtual rings are constructed by using combinatorial block designs together with an algorithm for realizing any size networks. It is shown that the bound on the maximum route length, under the two constraints, is O(√N) for an N-node network, This sublinear bound facilitates the throughput scalability property     

用波分复用技术设计和实现的双波长光纤环网

本文设计和实现了具有PCI总线峰值带宽传输能力的光互连网络接口卡。采用可编程门阵列实现硬件路由和同步流水线传输以减小数据包在网络中的通信延迟。为扩展网络规模,采用波分复用技术实现了双波长环网。通过无源光学器件实现双波长信号和合波和分束,通过探测器选择接收不同波长的光信号以实现波长路由。该网络结构扩展为多波长环网。     

Insufficiency of linear coding in network information flow

It is known that every solvable multicast network has a scalar linear solution over a sufficiently large finite-field alphabet. It is also known that this result does not generalize to arbitrary networks. There are several examples in the literature of solvable networks with no scalar linear solution over any finite field. However, each example has a linear solution for some vector dimension greater than one. It has been conjectured that every solvable network has a linear solution over some finite-field alphabet and some vector dimension. We provide a counterexample to this conjecture. We also show that if a network has no linear solution over any finite field, then it has no linear solution over any finite commutative ring with identity. Our counterexample network has no linear solution even in the more general algebraic context of modules, which includes as special cases all finite rings and Abelian groups. Furthermore, we show that the network coding capacity of this network is strictly greater than the maximum linear coding capacity over any finite field (exactly 10% greater), so the network is not even asymptotically linearly solvable. It follows that, even for more general versions of linearity such as convolutional coding, filter-bank coding, or linear time sharing, the network has no linear solution.     

On the reliability of links in a ring network

This paper analyzes the reliability of links in a computer network which is configured in a ring topology. It will be shown that the expression for reliability of elements connected in series is not adequate for computing the reliability of links in a ring network. Consequently, new expressions for computing such reliability for rings with and without back-up links are proposed. Furthermore, an optimal back-up links assignment which guarantees optimal links reliability is formulated.     

A Sink-Oriented Layered Clustering Protocol for Wireless Sensor Networks

Clustering is an effective technique to prolong network lifetime for energy-constrained wireless sensor networks. Due to the many-to-one traffic pattern in a multi-hop network, the nodes closer to the sink also help to relay data for those farther away from the sink, and hence they consume much more energy and tend to die faster. This paper proposes a sink-oriented layered clustering (SOLC) protocol to better balance energy consumption among nodes with different distances to the sink. In SOLC, the sensor field is divided into concentric rings, and the SOLC protocol consists of intra-ring clustering and inter-ring routing. We compute the optimal ring width and the numbers of cluster heads in different rings to balance energy consumption between intra-cluster data processing and inter-cluster data relaying. Cluster heads in a ring closer to the sink has smaller sizes than those in the rings farther away from the sink, and hence they can spend less energy for intra-cluster data processing and more energy for inter-cluster data relay. Simulation results show that the SOLC protocol can outperform several existing clustering protocols in terms of improved network lifetime.     

Service applications for SONET DCS distributed restoration

This paper determines the scope of network applications and services that could be offered using a SONET DCS-based self-recovering mesh architecture with distributed control. The study includes an outage impact analysis on network services and a determination of how network restoration time objectives will affect the applicability for the distributed controlled DCS network architecture. It is concluded that using SONET DCS distributed control architectures to provide more complete survivability of a network would support numerous applications. Future services will demand a fault-tolerant network with complete survivability; this may only be reached through integration of SONET DCS distributed control architectures with other survivable architectures such as cell relay networks (e.g., supporting SMDS) and self-healing rings     

Ring Network Design by Lagrangean Based Column Generation

We discuss the problem of designing a telecommunication network with the survivability requirement that the network should be composed of connected rings of links. The network design problem is then to choose links from a given network, and compose them into a number of rings. Furthermore, the rings should be connected at certain transit nodes. The traffic between rings may pass through other rings. Each ring is associated with a certain fixed cost depending on the length of the ring. We describe the problem, modeled as a linear integer programming problem, and a heuristic solution method, based on column generation and Lagrangean relaxation.     

有限环计算的数字式神经网络方法

本文提出一种用于有限环算术的数字式神比网络方法。它采用非对称的数字式神经网络结构，在整个矢量空间上具有唯一的平衡点，因而不存在计算误差。这种方法保持了神经网络的高度并行结构，能够实时完成有限环上的模运算。它还被应用于中国余数定理的实现。     

Measurement Based Resource Allocation for Interconnected WDM Rings

We present a measurement based resource allocation scheme for interconnected WDM rings in a metropolitan area network named DAVID (Data And Voice Integration over D-WDM). The network has a two level hierarchical structure, with a backbone of optical packet routers interconnected in a mesh, and metropolitan areas served by sets of optical rings connected to the backbone through devices called Hubs. The paper focuses on the operations of the media access protocol and on resource allocation schemes to be used in the metropolitan area network. A simple scheme for datagram (not-guaranteed) traffic is defined and its performance are examined mainly by simulation.