EPON系统中的E1电路仿真

EPON系统采用PON的网络拓扑结构、以太帧结构，实现数据业务的高速接入。如何增强以太网的能力，构筑多业务平台，实现实时音视频和IP数据在单一平台上传输是EPON研究中的关键问题之一，本对EPON中E1电路仿真技术及实现方案进行了研究。     

EPON生存性分析和可存活网络拓扑研究

针对EPON系统的4种树型自愈结构和3种环形自愈结构保护方案进行了存活性能的比较分析,给出了其中能提供最好生存性的网络拓扑结构.     

浅析EOC自发现自配置技术

在陕西广电网络现阶段的网络维护工作中,EPON/EOC系统网络拓扑结构只能通过人工方式进行维护和管理,对网络维护造成很大的不便,本文介绍了EOC自发现自配置技术,以实现EPON/EOC网络拓扑结构的自动维护,减少维护人员的工作量.     

EPON系统中的E1电路仿真

EPON系统采用PON的网络拓扑结构、以太帧结构,实现数据业务的高速接入。如何增强以太网的能力,构筑多业务平台,实现实时音视频和IP数据在单一平台上传输是EPON研究中的关键问题之一,本文对EPON中E1电路仿真技术及实现方案进行了研究。     

EPON助力广电双向改造

EPON的全千兆带宽、简单而成熟的以太网技术、无源网络特点也受到了广电运营商的关注,再加上EPON的树状无源光分配网络拓扑和广电的HFC网络拓扑的完全吻合,这使得EPON迅速成为广电双向改造的热点技术之一。     

Ms-EPON系统中的弹性保护倒换技术

创新地提出了一种应用于多业务EPON系统的保护倒换技术--弹性保护倒换技术。阐述了弹性保护倒换Ms-EPON系统的网络拓扑结构,论述了设计实现方案,分析了弹性保护倒换技术的特点。     

EPON网络管理系统中拓扑管理的设计与实现

阐述了拓扑管理的重要性,为了能够更加方便以太无源光网络(EPON)系统的管理,提出了一种基于B/S结构的EPON网管的拓扑管理设计方案.测试结果表明,能够快速、准确地分层显示网络拓扑图,具有Trap主动上报的功能,实现了拓扑管理的功能.     

有线电视接入网EPON+HINOC技术探析

在三网融合的大背景下,广电运营商采用EPON和HiNOC技术有助于综合利用有线电视网络资源,快速完成NGB接入层的双向化建设。在说明了广电双向接入网结构的基础上,分别研究了EPON和HiNOC的网络拓扑、协议结构和MAC层运行机制,并进行了关键技术的比对分析。     

EPON_EoC网络拓扑分层显示的设计与实现

EPON+EcC作为三网融合中双向改造的主流方案,为其构建统一网管系统是必要的,而以图形方式显示网络拓扑结构是网管系统的基本要求之一.在已实现的EPON和EoC设备统一管理方案及拓扑发现的基础上,结合Twaver SVG进行了网络拓扑多层显示的设计与实现,并完善了拓扑编辑、拓扑导出等功能.同时,在此基础上也实现拓扑显示...     

有线电视接入网络改造技术对比及分析

本文在"三网融合"的背景下,介绍有线电视接入网络的几种改造技术,阐述各自的特点,从网络拓扑结构、安全性、稳定性和维护管理等方面进行对比,分析EPON+EoC接入网技术的优势.     

Topology discovery in heterogeneous IP networks: the NetInventory system

Knowledge of the up-to-date physical topology of an IP network is crucial to a number of critical network management tasks, including reactive and proactive resource management, event correlation, and root-cause analysis. Given the dynamic nature of today's IP networks, keeping track of topology information manually is a daunting (if not impossible) task. Thus, effective algorithms for automatically discovering physical network topology are necessary. Earlier work has typically concentrated on either 1) discovering logical (i.e., layer-3) topology, which implies that the connectivity of all layer-2 elements (e.g., switches and bridges) is ignored, or 2) proprietary solutions targeting specific product families. In this paper, we present novel algorithms for discovering physical topology in heterogeneous (i.e., multi-vendor) IP networks. Our algorithms rely on standard SNMP MIB information that is widely supported by modern IP network elements and require no modifications to the operating system software running on elements or hosts. We have implemented the algorithms presented in this paper in the context of the NetInventory topology-discovery tool that has been tested on Lucent's own research network. The experimental results clearly validate our approach, demonstrating that our tool can consistently discover the accurate physical network topology with reasonably small running-time requirements even for fairly large network configurations.     

Distributed Topology Construction in ZigBee Wireless Networks

Topology control is one of the important techniques in wireless multi-hop networks to preserve connectivity and extend the network lifetime. This is more significant in ZigBee, since the address assignment scheme is tightly coupled with topology construction. For example, there can be orphan nodes that cannot receive the network address and isolated from the network due to predefined network configurations. In this paper, we propose a distributed topology construction algorithm that controls the association time of each node in order to solve the orphan node problem in ZigBee as well as construct an efficient routing tree topology. The main idea of the distributed topology construction algorithm is to construct primary backbone nodes by propagating the invitation packets and controlling the association time based on the link quality. Since the dynamically selected primary nodes are spread throughout the network, they can provide backbone to accept the association requests from the remaining secondary nodes which are majority in a network. In the performance evaluation, we show that the proposed topology construction algorithm effectively solves the orphan node problem regardless of network density as well as provides efficient tree routing cost comparable to the approximation algorithm for degree constrained minimum routing cost tree (DC-MRCT) problem.     

认知无线网络中拓扑重构的研究

随着异构网络融合和网络自适应化逐渐成为必然的发展趋势,认知无线网络随之出现,并提供了一种实现全局端到端目标优化的方法。认知无线网络由能自适应改变自身配置的网络设备组合而成,为设计灵活高效的拓扑策略提供了可能性和保障。提出了一种拓扑重构的控制策略,能够规划数据传输路由,在高效利用空闲频谱资源的同时,提升了传输的效率和性能。     

下一代有线数字电视用户驻地网结构仿真

介绍了下一代有线电视用户驻地网的结构、物理层及数据链路层配置、仿真建模,并对仿真结果进行分析,认为以太网交换器作为核心的星型结构,可满足网络传送高清电视、IP电话和网页的需求.     

A full transparent fiber-optic ring architecture for WDM networks

A fully transparent fiber-optic ring architecture for wavelength division multiplexed (WDM) networks is proposed. The physical topology of the proposed network is based on a single or multifiber ring. The nodes at the periphery of the network are connected onto the ring via a polarization-independent acoustically tunable optical filter (PIATOF). This device is used for injecting the transmission from each node at a predefined wavelength onto the ring and at the same time for accessing the transmission of the other nodes. Expressions are derived for the throughput of different network configurations     

Towards energy efficiency in virtual topology design of elastic optical networks

Elastic optical networks offer a reliable platform for achieving energy efficiency by supporting extensive optical grooming of variable‐rate data traffic along with the traditional electrical data aggregation methods. The procedure of routing and spectrum allocation in a topology of nodes has explicit effect to the amount of consumed power. A new energy‐efficient method for designing the virtual topology in IP‐over‐elastic networks is introduced and evaluated. It is concluded that it consumes less power under different elastic transponder types, it designs the virtual topology using fewer transponders, and finally, there is a slight increase in the number of end‐to‐end lightpath hops. The proposed method is characterized by high performance and low lightpath establishment complexity. Therefore, it is suitable for a broad range of network configurations and transponder types.     

Statistical analysis of crosstalk accumulation in WDM networks

Accumulation of inband crosstalk in all-optical networks is studied. By applying statistical methods, we have investigated how inband crosstalk accumulation influences the performance of optical networks of different configurations. Our study shows that there exists a delicate dependence between network topology and robustness with respect to accumulation of inband crosstalk. A method is proposed to design optical networks with optical paths satisfying a certain level of inband crosstalk performance     

Frame synchronization in a photonic network of time multiplexedspace switches via a feedback scheme

A method for frame synchronization in a photonic network of time multiplexed space switches is presented. The method, which is based on a feedback scheme, is first introduced for frame synchronization in a single-switch configuration. The feedback scheme is then extended to both hierarchical (tree topology) and nonhierarchical (general topology) multiswitch configurations. Using this feedback scheme has the advantage of providing a mechanism for frame synchronization to be achieved initially, without the need for accurate transmission time measurements, and allowing synchronization to be maintained within very tight bounds. The methods presented require additional electronics at the switches, but electronics only for control purposes, not in the path of the information bits. However, optical delay elements are needed in the path of information bits on some links of the network. The proposed schemes also reduce the amount of synchronization equipment needed, compared to other methods     

Impact of picocells on the capacity and energy efficiency of mobile networks

The deployment of small cells in mobile networks has aroused a large interest in the last few years. This paper investigates the impact of picocell deployment on the performance and power consumption of mobile networks. Since different network upgrades introduce different performance gains, comparing different configurations exclusively on their overall power consumption can be rather biased. For this reason, a new key performance indicator, termed “energy efficiency”, is introduced and used throughout this study, bringing together network performance and its overall power consumption. In the first section of the study, a theoretical analysis for the Erlang-like capacity of a network, considering a uniform topology and traffic, is performed, using queuing theory analysis, namely processor-sharing queues. Results show that in all cases the deployment of picocells improve the performance of the network, however the energy efficiency is noted to be dependent on the deployment scenario considered. In the second part of the study, a more realistic scenario with non-uniform topology and traffic is considered, which is carried out through a large-scale system level simulator. Results show that by deploying picocells in areas experiencing high levels of traffic, the energy efficiency of the network can be considerably improved.     

Ad hoc networking with Bluetooth: key metrics and distributed protocols for scatternet formation

Bluetooth is a promising technology for personal/local area wireless communications. A Bluetooth scatternet is composed of simple overlapping piconets, each with a low number of devices sharing the same radio channel. A scatternet may have different topological configurations, depending on the number of composing piconets, the role of the devices involved and the configuration of the links. This paper discusses the scatternet formation issue by analyzing topological characteristics of the scatternet formed. A matrix-based representation of the network topology is used to define metrics that are applied to evaluate the key cost parameters and the scatternet performance. Numerical examples are presented and discussed, highlighting the impact of metric selection on scatternet performance. Then, a distributed algorithm for scatternet topology optimization is introduced, that supports the formation of a “locally optimal” scatternet based on a selected metric. Numerical results obtained by adopting this distributed approach to “optimize” the network topology are shown to be close to the global optimum.