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。     

光网络的发展与展望

首先简要介绍了光网络的基本概念,然后阐述了光传送网的主要优势,接下来分别论述了IP业务量对传送网结构的影响、从点到点WDM向光联网演进的必要性和演进的步骤以及全光光交叉连接设备的现状与发展,最后阐述了光传送网络向ASON演进的必然趋势.     

面向IP的分组传送网发展思路

业务IP化触发了新一代光传送网——分组传送网的兴起,业务IP化对光传送网提出了更大带宽传送、更加灵活组网等新挑战。实现IP与传送融合的分组传送网定位于满足IP业务的高效传送、灵活组网、高可扩展性和高可靠性等方面。分组传送概念在不同发展阶段和不同网络层次所表现的形式不尽相同,在骨干网主要表现为IP over波分复用（WDM）／光传送网（OTN）／可重构光分插复用（ROADM）的大带宽传送,而在城域网范围主要表现为以传送多协议标签交换（T—MPLS）和电信级以太网（CE）为代表的分组交换和传送技术。     

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.     

WDM光网络的保护和恢复技术

文章概述了IP、SDH和WDM层网络的生存性技术,重点介绍了光传送网的光层生存性技术与光网络恢复技术,还对故障定位、多层生存性机制的协调等问题进行了简单介绍,最后给出了一个业务配置RWA算法与恢复RWA算法的实际方案。     

WDM网络管理的现状和发展

本文就当前WDM网络管理发展情况进行了,分析了WDM网络管理需求和管理结构,讨论了中国电信WDM网络管理建设的现状和问题,提出了未来光传送网的网络管理要求。     

波分复用的应用和发展

介绍了当前国际上的高速率光通信技术,波分复用的应用现状,讨论了波分复用光传送网的组网和保护问题,以WDM技术为基础形成全光传送网的技术要求,预测了WDM网络的发趋势和全光通信网的形成。     

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。     

电传送网向不传送网进化的过程

分两部分叙述了电传送网向光传送网进化的过程。第一部分叙述近年来以时分多路为基的电传送网的改进与发展,它采用同步数字体系,并在光纤传输线路上装用波分多路系统和光纤放大器。第二部分简单说明在不久的将来可能实用的、以波分多路为基础光传送网,其结构中的所有网络单元全是由光的代替电的。     

Network architecture for optical path transport networks

This paper proposes a new layered transport network architecture on which the WDM optical path network can be effectively created. The optical path network will play a key role in the development of the transport network that will realize the bandwidth-abundant B-ISDN. This paper extends the layered transport network architecture described in ITU-T Recommendation G.803 which is applied in existing SDH networks. First, we elucidate an application example of WDM optical path networks. Next, we propose a new layered architecture for WDM-based transport networks that retains maximum commonality with the layered architectures developed for existing B-ISDN networks. The proposed architecture is composed of circuit layer networks, electrical path layer networks, optical layer networks, and physical media (fiber) networks. The optical layer is divided into an optical path layer and an optical section layer. The optical path layer accommodates electrical paths. Optical section layer networks are divided into optical multiplex section (OMS) layer networks and optical repeater section (ORS) layer networks. The OMS layer network is concerned with the end-to-end transfer of information between locations transferring or terminating optical paths, whereas the ORS layer is concerned with the transfer of information between individual optical repeaters. Finally, a detailed functional block model of WDM optical path networks, the function allocation of each layer, and an optical transport module (OTM) are developed     

光网络技术的发展与应用

主要从TDM（时分复用）、WDM（波分复用）、光纤技术、节点技术及全光网络等方面的发展介绍了近阶段光网络技术的发展与应用。     

WDM optical network testbed and distributed storage application

In this article we present the details of a generalized multiprotocol label switching controlled wavelength-division multiplexing (WDM) optical network developed under the Optical Network Focused Interest Group (ONFIG) program in Singapore. The WDM network is controlled through a GMPLS control plane that consists of CR-LDP, LMP, and OSPF-TE. We conducted various field trials on the GMPLS-capable WDM optical network testbed with the main focus on distributed storage service application. We developed and evaluated a distributed storage services application on the WDM optical network testbed and demonstrated that incorporating a lightweight data transport protocol with optical network control could be an efficient approach for data-intensive storage applications by exploiting the dynamic connection establishment and backup protection features.     

向新一代传送网演进

阐述了新一代传送网的基本特征,讲述了以OTN为代表的透明联网技术的发展,及100Gbit/s与超100Gbit/s高速WDM系统的发展和挑战,并对超低损耗光纤和基于光纤的复用技术的发展进行了分析。     

OA&M framework for multiwavelength photonic transport networks

Photonic networks based on wavelength division multiplexing (WDM) and optical path technologies are expected to realize flexible, transparent, and cost-effective transport networks with a large transmission capacity. This paper explores the design framework of photonic transport networks taking into consideration the operation administration and maintenance (OA&M) functions required for the successful introduction of WDM systems based on the optical path concept. From the view point of network maintenance, clear distinction is made between the optical path layer and the optical section layer to facilitate accurate and smooth failure localization. The digital multiplexing span between physical multiplexing interfaces at the end-to-end digital nodes should have the same maintenance span as the corresponding optical path. We argue that cooperative maintenance by OA&M functions at both the digital and optical layers can be a practical way of network supervision. A supervisory (SV) signal transfer method and a configuration that is suitable for the terrestrial trunk network are also indicated. As an example, a practical SV system design methodology and an actual procedure developed for a single channel optical transmission system based on optical in-line amplifiers are introduced. Furthermore, application of the developed SV system and network restoration schemes is discussed for future WDM-based photonic networks. The OA&M aspects introduced will be valuable for creating future photonic network systems     

Photonic transport network architecture and OA&M technologiesto create large-scale robust networks

In order to realize a large-scale and robust photonic transport network, a network protection strategy and operation, administration, and management (OA&M) realization scheme in wavelength division multiplexing optical path (WDM OP) transport networks has been developed. This paper discusses the networking (restoration/protection) concepts in each optical layer and proposes the most suitable networking strategy. To develop the OA&M technique, the characteristic information format of each optical layer must be discerned. A network node interface (NNI) structure for the WDM OP transport network is proposed. The proposed NNI is defined as the optical transport module (OTM). An OP signal format is defined as the optical transport unit (OTU). Overhead information and schemes to transmit it are also discussed