WDM全光通信网技术及其发展

在IP业务的高速增长和WDM技术提供超大容量带宽资源的双重刺激下,传统光网络正在朝着适于传输IP业务的新一代光网络演进。本文描述了WDM光传送网的发展与现状,讨论了基于OXC和OADM的WDM光传送网技术,并对下一代光网络的发展进行了分析和展望。     

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．     

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 over WDM光网络的演进趋势

由于IP业务的指数增长以及WDM在传送网中的主导地位,将IP业务直接承载于WDM系统的IP ver DM光网络成为理想的选择。IP over WDM光网络可分为三个阶段,即：点到点IPoverWDM、IP0ver可重构WDM、IPover光交换的WDM。     

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光网络设计

系统介绍了 IP组网技术 ,一般地 ,IP光网络设计包括 IP光传送层设计和 IP业务层设计。重点介绍了 IP/ Ethernet over SDH技术、IP over re- configurable WDM技术和 p- cycle恢复技术     

全光传送网的关键技术与解决方案研究

随着IP业务和WDM技术的快速发展,传统光网络正朝着适于IP业务传输的全光网络方向演进。在详细分析全光网络关键技术（如全光交换、ROADM、OXC）发展的基础上,提出了全光传送网络的线路损伤管理和优化方案,以实现全光传送网络的实际应用。     

IP over WDM网光层QoS业务映射模型设计

在IP over WDM网络中,WDM光网作为底层传送网络,目前还不能完全解析IP层对业务QoS区分等信息.针对IP和WDM网络中两种不同的QoS机制,应用IP网络差分服务模式,通过UNI接口汇聚来自IP网络的流量,将其映射为光域中相似的业务需求,在光域中为不同QoS业务提供不同QoS保障的光连接通道,实现了WDM网络层的QoS区分服务.     

中兴通讯长途骨干网波分保护方案

1 引言 为满足GE/2.5 Gbit/s/10 Gbit/s等大颗粒数据业务的传送需求,并降低网络建设成本,IP Over WDM成为近期各运营商关注的焦点技术之一.IP Over WDM又名光因特网,它是由WDM系统和路由交换组成的数据通信网络,其核心是充分利用WDM技术引入的巨大传送带宽和高速路由器交换机的强大交换能力,在IP层与光层之间合理地实现流量工程、保护恢复、QoS和网络管理等优化配置,构筑一种简单高效的网络体系结构.     

IP over optical cross-connect architectures [Topics in Optical Communications]

IP over optical network architectures have been extensively discussed within the research literature over the past few years. However, although signaling protocols between IP routers and optical cross-connect networks have been standardized, large IP backbones are not typically deployed over optical cross-connect networks with automatic reconfigurability features, such as automatic restoration or dynamic establishment of new IP links. One of the most important criteria in determining whether an IP backbone should be carried over such an optical cross-connect network is economic viability. In this article we analyze and explore four architectures for a typical large ISP backbone. In contrast with some other published claims, our results suggest it is more economically attractive to bypass an intermediate cross-connect network, given current equipment and IP backbone network design requirements. However, for ISPs who also provide a large volume of private line services, we propose an integrated architecture for IP over optical cross-connect networks that may provide an attractive alternative for providing rapid and cost-effective restoration from network failures     

Strategies Towords Next Generation IP Over Optical Networks

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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.     

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.     

全光网络及其上传送IP的研究

讨论了网络的 IP化及 IP网络全光化趋势 ;讨论了全光网络的四种关键技术 ,包括光分插复用器 (OADM)、光交叉连接设备 (OXC)、高速路由器和全光路由 ;阐述了全光网络的三种网络结构以及在全光网络中传送 IP分组的三种方法。     

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     

Signaling and Control Procedures Using Generalized MPLS Protocol for IP over an Optical Network

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP‐centric signaling and control architecture based on the generalized multi‐protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross‐connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS‐based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user‐network interface and network‐network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to GMPLS signaling.     

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.     

ASON组播技术及其应用研究

业务的多样性和不断出现的新业务正在驱动网络的发展，以IPTV为代表的基于流媒体的业务对光网络提出了新的挑战，光网络需要引入组播功能，支持组播业务。组播功能的引入使得光网络的带宽利用率得到有效提高。组播是未来光网络必不可少的技术。层叠网络的进一步演进，将进一步融合IP组播和光网络组播。未来，可以通过降低光网络组播树的粒度来降低光组播的使用门槛，这将有利于促进组播技术的更广泛使用。     

Demand assigned capacity management (DACM) in IP over optical (IPO) networks

The demand assigned capacity management (DACM) problem in IP over optical (IPO) network aims at devising efficient bandwidth replenishment schedules from the optical domain conditioned upon traffic evolution processes in the IP domain. A replenishment schedule specifies the location, sizing, and sequencing of link capacity expansions to support the growth of Internet traffic demand in the IP network subject to economic considerations. A major distinction in the approach presented in this paper is the focus of attention on the economics of "excess bandwidth" in the IP domain, which can be viewed as an inventory system that is endowed with fixed and variable costs and depletes with increase in IP traffic demand requiring replenishment from the optical domain. We develop mathematical models to address the DACM problem in IPO networks based on a class of inventory management replenishment methods. We apply the technique to IPO networks that implement capacity adaptive routing in the IP domain and networks without capacity adaptive routing. We analyze the performance characteristics under both scenarios, in terms of minimizing cumulative replenishment cost over an interval of time. For the non-capacity adaptive routing scenario, we consider a shortest path approach in the IP domain, specifically OSPF. For the capacity adaptive scenario, we use an online constraint-based routing scheme. This study represents an application of integrated traffic engineering which concerns collaborative decision making targeted towards network performance improvement that takes into consideration traffic demands, control capabilities, and network assets at different levels in the network hierarchy.