ASON and GMPLS—Overview and Comparison

In automatic switched transport networks (ASTN), transport services of different granularity can be set up, modified and released on demand using the mechanisms in the control plane. Currently, this novel provisioning paradigm is being standardized under the umbrella of the automatic switched optical network (ASON) and generalized multiprotocol label switching (GMPLS) framework. This paper provides an overview of the ASON and GMPLS frameworks at the current stage of their development and aims in particular on comparing the concepts and pointing out some open issues. In this context, we first give a brief overview of ASON and GMPLS work, and then provide a concept and functionality mapping including network resource models, control plane architecture, discovery, call and control management, and resiliency. Finally we address some important provider requirements.     

ASON体系结构的研究

介绍了自动交换光网络的层次结构和广义多协议标记交换协议,讨论了自动光交换网络中的关键技术及实现方法。     

智能OXC在ASON中的应用

IP与光技术的融合要求底层光网络具有高度的灵活性和可扩展性，产生了全新的ASON（自动交换光网络），智能OXC（光交叉连接）设备是ASON中的最关键的设备。文中简单介绍了智能自动交换光网络的概念、网络结构，详细分析了ASON中智能OXC矩阵硬件结构和OXC控制平面信令路由功能，最后讨论了智能OXC相关协议及扩展的GMPLS技术。智能OXC强大的光交换能力结合智能信息路由协议，必将与现有网络融合向全智能光网络发展。     

Automatic transport plane resource discovery mechanisms for ASON/GMPLS ring networks

In this letter, we propose two novel mechanisms which enable GMPLS LMP to cope with the automatic discovery of all-optical transport planes. The feasibility of our contributions and their performances are assessed by simulations as well as experimental results over the ASON/GMPLS CARISMA field-trial     

Recovery of the control plane after failures in ASON/GMPLS networks

A reliable control plane plays a crucial role in creating high-level services in the next-generation transport network based on the generalized multiprotocol label switching (GMPLS) or automatically switched optical networks (ASON) model. Approaches to control-plane survivability, based on protection, and restoration mechanisms, are examined. Procedures for the control plane state recovery are discussed, including link and node failure recovery.     

Waveband grooming and IP aggregation in optical networks

An automatically switched optical network (ASON) can be used as the transport layer of generalized multiprotocol label switching (GMPLS) networks. The design of an ASON involves determining the number of optical cross-connects (OXC) in the network, the required number of ports per OXC, and the interconnection topology of the OXCs. Given the number of ports per OXC, we present a linear algorithm to find the number of OXCs and to identify a cost-effective topology. We then develop a scheme that can be used to perform waveband grooming for several different topologies of an ASON that uses single-layer multigranular OXCs. We identify the bottlenecks and investigate the effect of traffic grooming schemes in the design of an ASON as a function of the peak access rate per customer. We evaluate the topologies and architectures for a national trunk network.     

一种新型的ASON安全组播信令协议

针对自动变换光网络组播信令过程中存在的安全威胁,提出了一种高效的基于GMPLS RSVP-TE的安全组播信令协议。该协议采用P2MP(point-to-multipoint)信令模型,通过数字签名和消息反馈等安全机制,对信令消息中的不变对象和重要可变对象实施保护。考虑到组播成员的动态变化特性,采用高效的组密钥管理策略保证组通信的前向安全性和后向安全性。经仿真实验及分析表明,该协议在保证安全建立组播树的同时,取得了较好的连接阻塞性能和较低的密钥更新时延。     

下一代光传送网:自动交换光网络

为适应网络动态化的要求,国际电信联盟标准化组织(ITU-T)提出了自动交换光网络(ASON)的概念.文章对ASON的网络总体结构、控制层面组成、控制协议及其与广义多协议标签交换(GMPLS)结构的关系作了概要的描述,并对ASON和光互联网进行了比较.     

基于GMPLS协议的ASON试验平台

文章介绍了清华大学自主研发的基于通用多协议标签交换(GMPLS)协议的自动交换光网络(ASON)试验平台.试验平台由3个层面构成,分别为传送层面、控制层面和管理层面.传送层面由4个光交叉连接(OXC)和1个光上下路复用器(OADM)构成的传送网络组成;控制平面由多个协议模块构成,包括链路管理、路由和信令模块,这些协议的实现都是基于互联网工程任务小组(IETF)的GMPLS协议开发和实现的;管理平面完成配置管理和故障管理,包括网元管理以及软永久连接的触发等.试验平台支持动态可配置的网络拓扑、自动邻居发现、受限路由以及光层快速的保护和恢复功能.     

A quantitative study on the influence of ASON/GMPLS on OPEX

ASON/GMPLS is promoted as one of the key technologies to reduce operational expenditures (OPEX) of network operators, since it provides the tools for automating the network operations. This paper gives a detailed model and qualitative analysis of the major OPEX-affecting operation processes in the area of core and metropolitan area transport networks. Moreover, a first quantitative evaluation of the changes in the operational efforts induced by ASON/GMPLS is described. The evaluation shows a significant potential to reduce OPEX, which is to some extent independent of the type of operator.     

用于ASON中的光交叉连接设备

光交叉连接(OXC)技术是光节点的关键技术,OXC是自动交换光网络(ASON)的核心,为此阐述了ASON的基本概念和特点,以及OXC的结构和工作原理,讨论了目前实现智能OXC的关键技术:智能光MEMS(微电子机械系统)技术和通用多协议标签交换技术.     

自动交换光网络控制平面中的GMPLS管理器

自动交换光网络(ASON)指的是直接由控制系统下达信令来完成光网络连接自动交换的新型网络,它赋予了原本单纯传送业务的底层光网以自动交换的智能,它的具体实现要依靠通用的多协议标签交换(GMPLS)协议。首先对ASON和GMPLS技术作了一个简单介绍,然后说明了GMPLS控制平面的软件结构,最后重点分析了ASON控制平面中的GMPLS管理器功能及应用。     

自动交换光网络中光电子器件的进展

光网络正在向高速大容量、良好的扩展性和智能化的方向发展。自动交换光网络的出现是光传送网技术的重要突破,光电子器件功能的增强与性能的提高将对其实现与发展起决定性作用。本文介绍了自动交换光网络中一些光电子器件的重要特性和发展趋势。     

下一代光传送网ASON

提出当今解决光传送网所面临问题的方法,是采用既能低成本建网又能智能化完成交换连接的自动交换光网络( ASON );介绍回顾了光传送网 ASON 技术的产生和取得的成果,以及 ASON 中几种关键控制平面技术的发展情况;阐述了 ASON 控制平面与传统传送网的本质区别、管理平面智能化管理特点所带来的 3 种优点,以及传送平面中光交叉连接( OXC )的 6 种主要交换结构、发展方向和存在的主要问题;最后综述了新一代基于数字同步系列(SDH )提供多种业务、集成传输、交换和路由功能的多业务传送平台(MSTP )技术,并描述其新功能和远期目标。     

ASON网络中一种新型的域间节点故障定位机制

在研究链路管理协议(LMP)单域故障定位的基础上,提出了一种自动交换光网络(ASON)的域间节点故障定位的新型方法.基于网关节点跨域通信的域间节点故障定位机制,利用ASON分布式控制平面完成故障定位功能,可以不依赖于传送平面的编码方式和网管人员的参与,并在各种域间节点故障情形下分别阐述了定位机制的工作原理以及定位过程.     

自动交换光网络网管系统的设计与分析

自动交换光网络（ASON）在光传输网络之上引入控制平面，可以支持动态波长连接的建立，动态地分配网络资源，因此一出现就引起了广泛的关注。ITU－T等组织定义了大量关于控制信令方面的规范，但是没有给出任何与网络管理方面相关的内容。本文针对ASON网络的特点，提出了适合ASON网络的基于CORBA技术实现的域间网络管理方案，然后对ASON的基本管理功能需求进行了分析，其中着重分析了ASON引入的控制平面的管理需求，为控制平面管理功能的实现做出了理论指导。最后，对如何应用CORBA技术实现网管系统进行了分析。     

PNNI-based control plane for automatically switched optical networks

Much effort has been spent on the definition of control plane protocols for automatically switched optical networks (ASON). Most of the proposals brought into the standardization for an International Telecommunications Union-Telecommunication Sector, Internet Engineering Task Force, and Optical Internetworking Forum are based on Internet protocol concepts. One such proposal is the generalized multi-protocol label switching (GMPLS), an extension of the MPLS traffic engineering control plane model that includes nonpacket switched technologies (time, wavelength, and fiber switching). Recently, the potential use of private network-network interface (PNNI) in ASONs has been discussed as an alternative proposal by the standardization bodies. The goal of this paper is to appropriately adapt asynchronous transfer mode into an optical PNNI (O-PNNI) protocol that can be used as the control plane of ASONs. The paper also provides a critical viewpoint on the potential usage of either O-PNNI or GMPLS control plane and analyzes the pros and cons of each. The methodology adopted toward devising O-PNNI hinges on reviewing PNNI along with ASON recommendations in order to determine the set of PNNI features that require adaptation. Having identified these features we engineer and present appropriate solutions relating to routing, signaling and addressing aspects.     

自动交换光网络的GMPLS实现及应用

介绍了自动交换光网络(ASON)与通用多协议标记交换(GMPLS)之间的关系,分析了GMPLS的层次结构模型,针对实际应用介绍了信令、路由和链路管理等协议,并在此基础上给出利用GMPLS实现ASON控制平面的一般方法和标记交换路径(LSP)创建过程,最后阐述了ASON的应用及存在的问题。     

Resource discovery in ASON/GMPLS Transport Networks

Automatic resource discovery plays a significant role in next-generation optical networks, where nodes can maintain a large number of input/output ports (fibers, wavelengths, time slots, etc.). This automation avoids long and tedious manual node configurations and minimizes resource misconfiguration probability, which can result in high cost savings for network operators. The generalized multiprotocol label switching (GMPLS) Link Management Protocol (LMP) has been defined to provide such functionalities. However, it requires optical nodes to transmit in-band information, thus requesting link termination on each incoming port. This issue, in transparent optical networks, implies additional hardware, high complexities, or even signal losses. This article proposes and evaluates novel extensions to standard LMP that cope with the discovery of all-optical transport planes. In addition, playing a crucial role in ASON/GMPLS networks, this article also generically covers the automatic discovery of the control plane.     

基于GMPLS的ASON生存性技术研究

自动交换光网络（ASON）是一种能够自动完成网络连接的新型网络。控制面技术是其核心,一些协议（如GMPLS）正在逐步应用到ASON控制面中。网络生存性是指网络发生故障时提供连续业务的能力。基于GMPLS的网络生存性技术对于网络的运营具有重要的意义。本文介绍了光网络的生存性技术并结合GMPLS与ASON控制平面对光网络的生存性进行了较为深入的研究。