IP over WDM光网络技术及其实现方案

从光传送网的发展趋势出发,分析了IP over WDM光网络的网络结构和协议规范.讨论了IP over WDM光网络的相关技术,并对分组交换技术进行了较为系统的介绍,最后,为了实现IP over WDM光网络,提出了6MPLS T-MPLS和GMPLS ASON的解决方案.     

IP over WDM网络最小功耗模型和休眠机制研究

针对IP over WDM网络,建立了整数线性规划(ILP)最小功耗模型,计算了满足峰值业务需要开启的设备数目;对于低峰业务提出休眠机制,分别利用最小光路数算法与最小跳数算法,在保证连接无阻塞的情况下找出空闲设备,对比峰值业务得到不同算法下的设备使用率,确定IP over WDM网络的节能潜力。结果表明,ILP优化模型的网络功耗最小,最小光路数算法次之;低峰业务下利用休眠机制可以关闭设备的比例占40%～60%;采用最小光路数算法的休眠机制节能效果较优。     

IP over DWDM光互联网技术

文中对基于 IP over WDM的新型数据网络体系结构——光互联网络技术进行了探讨。在分析三种构造未来信息网络解决方案的基础上 ,着重对基于 IP over WDM的光互联网络的关键技术和未来发展方向进行了研究。     

IP over WDM光网络联合保护策略

随着Internet和网络技术的发展,IP over WDM光网络成为下一代通信网最理想的解决方案。因此,IP over WDM光网络的生存性是下一代通信网成功与否的关键。在传统的保护策略中,IP层和WDM层之间不交换网络的状态信息。探讨了IP层和WDM层保护机制互相协作的必要性,并在通用多协议标签交换GMPLS的基础上,提出了联合保护策略的思想。     

WDM与IP业务的融合

分析了WDM光网络的结构以及联网技术的演进过程，对如何实现IP直接over WDM，发挥WDM光传送网的巨大带宽优势进行了研究，提出了MPLS与GMPLS是解决当前IP层与光层的融合以及跨层管理问题的关键技术。     

IP over WDM的演进之路

Internet流量的指数级增长和波分复用(WDM)在传送网中的主导地位，使得直接利用WDM技术承载IP业务的IP over WDM光网络成为理想的选择．通过对其三个发展阶段的介绍和分析，文章旨在探讨IP over WDM光网络的演进思路．     

光因特网的一种新构架

近几年来,由于低损耗单模光纤技术的进步,光网络已经被用来满足各种应用的需求。波分复用(WDM)技术被认为能更有效地利用巨大的光纤带宽。IP over WDM技术是网络发展的一个重要方向。本文提出了一种新型混合模型网络结构,并进行了模拟仿真研究,结果表明此技术是可行的。     

面向未来的通信骨干网

网络信息爆炸式地增长和IP技术不断发展极大地促进宽带IP骨干网的迅猛发展,基于光波分复用的IP传送网技术（光因特网）提供了最有效的IP骨干网解决方案。简要介绍了IP over WDM协议分层模型和网络体系结构,讨论了IP over WDM的帧结构等关键性技术,探讨了IP over WDM的发展前景。     

IP/MPLS-over-WDM的网络生存性

Internet的发展和数据业务的爆炸性增长对当前网络提出了更高的要求。网络将演变为IP/MPLS—over—WDM。对于这种以光网络为基础的网络构架,网络的生存性问题变得尤为重要。本文首先介绍了MPLS网络的生存性机制。由于以数据业务为中心的光网络至少包含IP层和光层,本文提出了几个在多层网络生存性面临的问题,并给出了几种方案。最后,讨论了IP/MPLS—over—WDM特有的生存性思考。     

IP over WDM网络中能耗自感知的混合疏导专有保护算法

针对绿色生存性IP over WDM网络中资源开销大、网络阻塞率高的问题,提出一种能耗自感知的混合疏导专有保护(HG-PA-DPP)算法。首先在IP层的核心路由器对低粒度业务请求集中疏导;然后通过实时感知WDM层的链路负载和双层器件带来的链路能耗状态定义链路权值,基于分层图在不同波长平面上为各业务请求寻找权值小且链路分离的工作路径和保护路径,同时在业务的中间节点处对不需要光-电-光转换的光路进行光旁路处理;最后,将空闲或保护资源设置为休眠模式以实现节能。仿真结果表明,所提算法在高负载时有着更好的节能效果,且在大网络拓扑下资源开销(RO)为传统算法的76.5%,阻塞率(BP)仅为传统算法的61.1%。     

Will video caching remain energy efficient in future core optical networks?

Optical networks are expected to cater for the future Internet due to the high speed and capacity that they offer. Caching in the core network has proven to reduce power usage for various video services in current optical networks. This paper investigates whether video caching will still remain power efficient in future optical networks. The study compares the power consumption of caching in a current IP over WDM core network to a future network. The study considers a number of features to exemplify future networks. Future optical networks are considered where: (1) network devices consume less power, (2) network devices have sleep-mode capabilities, (3) IP over WDM implements lightpath bypass, and (4) the demand for video content significantly increases and high definition video dominates. Results show that video caching in future optical networks saves up to 42% of power consumption even when the power consumption of transport reduces. These results suggest that video caching is expected to remain a green option in video services in the future Internet.     

Dynamic hybrid grooming based on power efficiency in green IP over WDM networks

Due to the rapid growth of various applications, the network devices scale and complexity are significantly increased. Meanwhile, to deal with the burst IP traffic, the network devices need to provide continuous services, which will result in the excessive power consumption. Meanwhile, with the development of IP network and intelligent optical switch network, the backbone network tends to be an IP over wavelength-division-multiplexing (WDM) network. Therefore, it has attracted wide interests in both academic and industrial communities to build power-efficient (i.e., green) IP over WDM network, where we can switch several IP-level requests as one unit in the WDM optical layer. This method is called hybrid grooming and it requires less component power than that of electronic IP routers in the IP layer. Under this hybrid approach, the traffic grooming multiplexes many IP-level requests into a high-capacity lightpath; meanwhile the reduction in power consumed by optical-electrical-optical conversions is achieved through optical bypass. However, the power consumed by components used to establish lightpaths should also be considered. One network with the higher power efficiency not only saves more power followed by hybrid grooming but also requires the lower power consumption of establishing lightpaths. In this paper, to improve the power efficiency of dynamic IP over WDM network, we design two kinds of Wavelength Integrated Auxiliary Graphs (WIAGs), each of which contains one Virtual Topology Layer and multiple Wavelength-Plane Layers. Based on WIAGs, we propose two heuristic algorithms named single-hop grooming with considering power efficiency and multi-hop grooming with considering power efficiency (MGPE) since grooming is NP-hard. Simulation results demonstrate that MGPE obtains the higher power efficiency, although it has the slightly higher time complexity; the power efficiency mainly depends on the kind of grooming strategy (single- or multi-hop) we use while the increasing number of available transceivers in each node cannot improve the power efficiency, although it can make blocking probability decrease.     

The interface between IP and WDM and its effect on the cost of survivability

A summary of research on survivable IP networks overlaid over WDM networks is presented. The WDM networks are part of optical transport service providers, who lease lightpath services to institutions with IP networks. The lightpath services realize IP links for IP networks, and they have different protection grades such as unprotected and protected. The research included considering new network survivability requirements and incorporating them into network design problems. The cost of survivable IP over WDM networks is compared over three scenarios. Each succeeding scenario has the WDM network provide more flexible services, and the IP and WDM networks become more integrated. We consider the problem of setting up lightpaths for an IP network so that the network will remain connected after a fiber link fault. Algorithms to find the lightpaths and minimize cost are given. The network costs under the three scenarios are compared by simulations.     

Advances in the management and control of optical Internet

Given the ever increasing demand for network bandwidth, and the phenomenal advances in optical wavelength division multiplexing (WDM) networking technologies, a major component of the next generation Internet will be an Internet protocol (IP)-based optical WDM network. As IP over WDM networking technologies mature, a number of important architectural, management and control issues have surfaced. These issues need to be addressed before a true next generation optical Internet can emerge. We enumerate some of the key architectural, management and control issues and discuss corresponding approaches and advances made toward addressing these issues. We first review the different IP/WDM networking architectural models and their tradeoffs. We outline and discuss several management and control issues and corresponding approaches related to the configuration, fault, and performance management of IP over dynamic WDM networks. We present an analysis and supporting simulation results demonstrating the potential benefits of dynamic IP over WDM networks. We then discuss the issues related to IP/WDM traffic engineering in more detail, and present the approach taken in the NGI SuperNet Network Control and Management Project funded by DARPA. In particular, we motivate and present an innovative integrated traffic-engineering framework for reconfigurable IP/WDM networks. It builds on the strength of multiprotocol label switching for fine-grain IP load balancing, and on the strength of reconfigurable WDM networking for reducing the IP network's weighted-hop-distance, and for expanding the bottleneck bandwidth     

基于路径的整数线性规划方法在阻塞IP over WDM网络中能耗优化的应用

针对容量有限的透明IP over WDM网络模型,该文提出一种基于路径的整数线性规划(ILP)方法来优化网络的能耗。相对基于连接的整数线性规划方法,该方法可以在光层提供更多的路径选择组合。仿真结果显示,基于路径的整数线性规划方法能够通过选择更优的光路组合进一步降低网络的能耗。     

在IP/MPLS over WDM网络中基于准入机制的区分服务

在IP over WDM网络中,光层可以通过建立新的光路来为IP层提供带宽.如何利用光层有限的资源使网络服务提供商的利润最大化是流量疏导的一个重要目标.文章基于迭加网络模型,研究IP/MPLS over WDM网络的准入机制,设计算法在不影响整体效率的前提下为网络提供区分服务.     

Investigations on combined XPM and FWM effects on optical pulse propagation in dynamic IP traffic over WDM networks

The influence of IP bursty traffic on combined nonlinear effects of XPM (cross phase modulation) and FWM (four-wave mixing) in IP over WDM networks are investigated and calculated by solving the nonlinear Schrodinger equation (NLSE) using a novel method under two conditions: on–off Poisson distributed IP traffic and self-similar traffic. Different eye diagrams are obtained under various IP traffic types and input optical powers. When the input power of a single channel is larger than 3 dBm, the effect of IP bursty traffic will deteriorate eye diagrams dramatically in a 40-channel WDM network. We also calculate the FWM powers and interchannel power distribution under different IP traffic loads. Based on the interchannel power distribution, we could find out which channels affect the probe channel seriously by the FWM effect. All these numerical results are useful for the Quality-of-Service (QoS) design, traffic grooming, lightpath routing, and wavelength assignment of IP over WDM networks.     

Evolution of WDM Optical IP Networks: A Cost and Energy Perspective

We review technologies and architectures for WDM optical IP networks from the viewpoint of capital expenditure and network energy consumption. We show how requirements of low cost and low energy consumption can influence the choice of switching technologies as well as the overall network architecture.