All-optical WDM to TDM transmultiplexer

An all-optical WDM to TDM converter, or transmultiplexer, is described. The transmultiplexer is based on optical frequency conversion by gain compression in semiconductor optical amplifiers. Operation of the transmultiplexer is demonstrated experimentally, and bit error rate measurements are reported     

全光网中的波长变换器放置问题研究

波长变换器的出现可有效地提高WDM全光网的网络性能。文童对WDM全光网中的波长变换器放置问题进行了深入的研究,详细阐述了各种波长变换器放置算法的设计思想,并对各种算法的性能以及时间复杂度等参数进行了分析,并在典型拓扑上进行了仿真。     

All-optical multipoint-to-point routing in WDM mesh networks

In this article, the routing and wavelength assignment (RWA) problem for supporting multipoint-to-point communications in all-optical WDM mesh networks is investigated. Two efficient algorithms, namely reverse shortest path tree routing (RSPT) and k-bounded edge disjoint path routing (EDPR), are proposed. We proved that the problem of minimizing the total cost while establishing a multipoint-to-point session can be solved in polynomial time of O(|V|log|V|?+?|V|?+?|E|) by the RSPT algorithm, where |V| and |E| denote the number of nodes and the number of edges in the network, respectively. Nevertheless, the solution provided by the EDPR algorithm produces a significant reduction in the maximum number of wavelengths required per link (i.e., the link stress) for a multipoint-to-point session compared to RSPT algorithm. EDPR algorithm can also approximate to the optimal total cost with a ratio of k. Simulations are done to assess these two algorithms. Numerical results demonstrate their efficiencies in supporting multipoint-to-point communications in all-optical WDM networks.     

可生存光网络中的不同QoS策略

随着光网络技术的不断发展,网络的生存性及其QoS问题越来越受到关注.文章围绕可生存光网络中的不同QoS策略这一问题,首先介绍了可生存光网络及其QoS参数的概念,解释了为什么如今要考虑可生存光网络中的不同QoS策略.接着以传统光网络生存性方法的一般分类图为依据,从原理、性能等方面归纳比较了以往各种生存性方法,并分析了各自的优缺点.最后根据考虑可生存性光网络中QoS参数的不同,具体描述了用来支持不同业务的各种光网络生存性方法.     

All-optical 1310 nm WDM to 1550 nm OTDM transmultiplexing

1310 to 1550 nm transmultiplexing based on nonlinear polarisation rotation in a single semiconductor optical amplifier is proposed. Error-free 2/spl times/5 Gbit/s 1310 nm to 10 Gbit/s 1550 nm transmultiplexing is demonstrated.     

WDM光网络功率管理的数值模拟

本文提出了一种新的WDM光网络功率管理方案,即同时考虑同频串扰和自发辐射噪声的总功率。给出了方案的数学模型,并进行了仿真计算。结果表明,同频串扰对WDM光网络的规模和光信号的质量有着重要的影响。对于使用机械光开关的WDM关网,串扰对系统的影响程度主要取决于解复用器的隔离度。对串扰较小的网络,提高输出EDFA的增益和监测点光功率设定值会提高光信号质量。     

基于自相似业务的全光网中波长变换器放置问题研究

对基于自相似业务的WDM全光网中的波长变换器放置问题进行了深入的研究,详细阐述了各种波长变换器放置算法的设计思想,对各种算法的性能以及时间复杂度等参数进行了分析,并在典型拓扑网络上进行了仿真。     

Differentiated QoS for survivable WDM optical networks

Optical networks based on WDM technology have become a promising solution to realize transport networks that can meet the ever-increasing demand for bandwidth. As WDM networks carry a huge volume of traffic, maintaining a high level of survivability is an important and critical issue. The. development of GMPLS switching technology led to the direct integration of IP and WDM. In these IP-over-WDM networks different applications/end users need different levels of fault tolerance and differ in how much they are willing to pay for the service they get. The current trend in network development is moving toward a unified solution providing support for voice, data, and various multimedia services. Therefore, it imperative that WDM networks incorporate fault tolerance to single or multiple component failures, protection bandwidth, recovery time, and recovery granularity besides resource utilization and call acceptance ratio. This article presents a survey of various methods that have been proposed for providing service differentiation in survivable WDM networks and discuss their performance. Such methods are broadly classified under various paradigms such as differentiated reliability, R-connections, quality of protection, and quality of recovery.     

Virtual SDN embedding with differentiated QoS under multiple controller

In SDN virtua1ization environment under mu1tip1e contro11ers,with the goa1 of minimum the mean de1ay between contro1 paths,the 1oad imba1ance of contro11ers,and the cost of embedding,mathematica1 mode1s of the contro11er p1acement and the virtua1 SDN embedding prob1em were bui1t,and a virtua1 SDN embedding method with differentiated QoS under mu1tip1e contro11ers was proposed.The simu1ation resu1ts show that the proposed a1gorithm can satisfy various virtua1 networks QoS for users,keep 1oad ba1ance between contro11ers and increase the acceptance ratio and the revenue/cost ratio.     

基于WDM全光网的发展及展望

概述了基于WDM全光网的由来和基于WDM全光网的发展、技术特点、关键节点设备和目前的状况，以及其于WDM全光网的发展趋势等。     

All-optical cross-connect using feed-forward optical buffers with and without QoS: an analysis

An analytical model is derived to evaluate the performance of an optical switch using a feed-forward fiber delay line (FDL) per output for contention resolution. Two different forwarding algorithms for the switch are presented and evaluated: a simple forwarding algorithm (SFA) that is easier to implement, and an enhanced algorithm that provides better performance in terms of both packet loss probability and packet delay. The analytical model can be utilized with both packet and burst switching schemes to characterize the performance of the proposed architecture. Results show that the proposed architecture reduces the packet loss probability compared to that without FDLs. Finally, the same architecture is shown to be capable of supporting Quality of Service (QOS).

多光纤WDM网中的QoS路由算法

利用区分光业务(DOS)模型可以将WDM光传送网中客户层(如IP)具有不同QoS要求的业务汇聚力较粗粒度的流,直接映射到光信道上,从而使客户层业务的不同QoS要求可以体现在DOS域的边缘光节点处的光路建立请求的不同优先级上。该文首先探讨了如何将多光纤WDM网转化为波长图,从而一次性解决选路和分配波长(RWA)问题,在此基础上,提出两种用于多光纤WDM网的QoS路由算法,对二者进行了比较,并进行了计算机仿真。     

IP over WDM 网络中的QoS机制

本文讨论了IP over WDM网络中的三种不同的光交换技术并分别对这三种交换技术中的QoS机制做了比较和分析。     

Minimum cost event driven WSN with spatial differentiated QoS requirements

Wireless Networks - In wireless sensor networks applications like rare-event detection, maximizing lifetime, minimizing end-to-end delay, and minimizing the network cost, are some of the most...     

Optical multicast provisioning with differentiated leaf availability guarantee in WDM networks

As multicast applications become more and more popular, implementing multicast in the optical domain has attracted increased attention due to its more efficient bandwidth usage. And also these services have quality-of-service requirements. In this article, the problem of cost-effective optical multicast provisioning to satisfy the differentiated leaf availability requirements is formally stated. A Mixed Integer Linear Program formulation is proposed for provisioning dedicated light-tree protection with differentiated leaf availability guarantee. The algorithm is so complex and infeasible that we also propose a feasible two-step approximate approach to solve the problem. Different from the previous schemes, our scheme finds out the primary light-trees and backup paths for destination nodes whose availability is not satisfied. Because of taking the different leaf availability requirements into account, the proposed algorithm obtains a more efficient feasible solution requiring less network resources.     

A differentiated optical services model for WDM networks

This article addresses the issues of scalable end-to-end QoS in metropolitan DWDM networks serving as transit networks for IP access networks. DWDM offering a few wavelengths has been deployed in the past in backbone networks to upgrade point-to-point transmission where sharing is based on coarse granularity. This type of DWDM backbone network, offering a few light-paths, provides no support for QoS services traversing the network. As DWDM networks with larger numbers of wavelengths penetrate the data-centric metro environment, specific IP service requirements such as priority restoration, scalability, dynamic provisioning of capacity and routes, and support for coarse-grain QoS capabilities will have to be addressed in the optical domain in order to achieve end-to-end QoS over a DWDM network. We propose a QoS service model in the optical domain called differentiated optical services (DoS) based on a set of optical parameters that captures the quality and reliability of the optical lightpath     

Novel wavelength and bandwidth allocation algorithms for WDM EPON with QoS support

Ethernet passive optical networks (EPONs) have been considered as the one of the most promising candidates for next-generation access networks. However, the EPON architecture although cost effective is bandwidth limited and quality of service (QoS) support is still a major concern. In this paper, we propose a cost-efficient wavelength division multiplexing (WDM) EPON architecture. We present two wavelength and bandwidth allocation algorithms with full QoS support to fulfill all requirements of new application and services in a converged triple play network. We analyze and compare the presented models and algorithms in terms of delay, jitter, queue occupancy, throughput and overall system performance. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed architecture and algorithms.     

Differentiating QoS and Un-conflicting Channel-timeslot Allocation Algorithm in WDM

A new effective and reliable channel-timeslot allocation algorithm has been proposed, which is applied in WDM optical networks using fiber as their media to allocate the operational request. This new algorithm can differentiate the priority of all requests and avoid conflict and collision in the process of distributing channel and timeslot for the data waiting for transmission. The method in calculating the best wavelength channel and the best timeslot number is simply given. The algorithm is carried out in a math language. On the basis of the experiment results, the performance and feasibility of the algorithm are analyzed, which prove that the allocation method can reach the requirements of an algorithm both in space complexity and time complexity.     

WDM网络中支持QoS的路由与波长分配算法

针对波分复用(wDM)网络中的路由与波长分配问题。提出了一种支持服务质量(QoS)的约束搜索算法。基于多目标规划模型,这种搜索算法可为网络各节点创建路由表,根据路由表信息求出非支配路径集合,从而一次性完成寻找路由和分配波长两项任务。仿真实例证明了该算法的有效性。     

Partial SRLG-disjoint shared path protection with differentiated reliability in survivable WDM network

This paper addresses the problem of shared path protection algorithm in survivable wavelength-division-multiplexing (WDM) optical networks, taking into consideration of differentiated reliability (DiR) under Shared-Risk-Link-Group (SRLG) constraint. A subset of network links that share the risk of failure at the same time are said to be in a common SRLG. Rather than the conventional complete SRLG-disjoint shared path protection, we introduce a heuristic Partial SRLG-disjoint Shared Path Protection algorithm (Pd-SPP) based on the concept of SRLG conditional failure probability, to provide differentiated reliability protection. The main target of our work is to improve the network resource utilization ratio under the DiR constraint. We adopt the ideas of partial SRLG-disjoint and the K-shortest paths algorithm such we can efficiently solve the “trap” problem. The experimental results show that our algorithm outperforms the complete SRLG-disjoint shared path protection in both blocking probability ratio and network resource utilization, i.e. the results are found to be promising.