GMPLS技术及其路由算法

通用多协议标签交换（ GMPLS）是由多协议标签交换（MPLS）发展而来,它是MPLS向光层扩展的必然产物.GMPLS将时隙、波长和光纤端口作为标签用子数据转发,通过采用扩展的信令、路由协议和新增的链路管理机制以适应对智能光网络进行动态控制和传送信令的要求,动态提供网络资源并增加网络的存活性.本文着重比较了GMPLS与MPLS,说明其如何改进MPLS,并提供了GMPLS在光控制平面的应用解决方案.最后,谨慎分析了GMPLS的前景及其需要解决的问题     

GMPLS协议中的路由和波长分配技术

因特网工程工作组（IETF）制定的通用多协议标签交换协议（GMPLS）,作为光网络的控制平面协议,推动了光网络的智能化进程。路由和波长分配问题（RWA）是光网络智能化的核心问题之一。在介绍RWA算法和GMPLS协议的基础上,分析了不同RWA算法、不同RWA机制对网络信息的需求,描述了GMPLS协议为解决RWA问题所做的标准化工作,并分析了与RWA相关的网络信息分发格式。     

GMPLS与自动交换光网络

GMPLS(通用多协议标签交换)是MPLS技术向光网络发展的产物。它有效地实现了IP和WDM光网络的无缝融合，很好的满足了自动交换光网络控制面的需要。本文主要研究了GMPLS的接口类型和标签、自动交换光网络(ASON)的控制面以及GMPLS在ASON中的应用。     

MPLS向GMPLS迁移技术研究

多协议标签交换（MPLS）向通用多协议标签交换（GMPLS）的迁移，实际就是，MPLSTE控制层面向GMPLS控制层面发展的过程。在迁移过程中，MPLS和GMPLS设备或网络同时存在，将出现多种互联情况。标准的互联功能要求，在使用GMPLS技术的同时，保持现有的IP／MPLS网络不受影响。     

电信辞库

通用多协议标签交换通用多协议标签交换(GMPLS)是一种在多协议标签交换(MPLS)的基础上发展起来的通用控制平面协议规范。GMPLS对MPLS流量工程(MPLS-TE)进行了扩展，使得它不仅适用于包交换，还适用于时分交换(如SDH/SONET、PDH)、波长交换以及空间交换。在GMPLS中，还提出了一些例如双向标签交换路径(Bi-directionalLSP)、链路绑定(LinkBundling)和LSP层次(LSPHierar鄄chy)等新的概念。GMPLS体系结构涵盖了为多种光虚拟专用网光虚拟专用网(OVPN)是指不用建设专用的网络，利用一些控制和管理技术，将光网络中的某一…     

GMPLS--智能光网络的核心技术

GMPLS是MPLS向光网络扩展的产物,能支持分组交换、时分交换、波长交换和光纤交换,它实现了IP和WDM光网络的融合,很好地满足智能光网络控制面的需要.对GMPLS的标签、层次化LSP、路由与寻址、信令和链路管理等方面加以分析,最后对GMPLS的意义进行了概括.     

通用多协议标签交换技术

通用MPLS（GMPLS）是MPLS向光网络扩展的必然产物,它为了适应对智能光网络进行动态控制和传送信令的要求而对传统的MPLS进行了扩展、更新。使用GMPLS可以为用户动态地提供网络资源,以及实现网络的保护和恢复功能。与传统的MPLS相比,GMPLS在以下几个方面得到了改进。多种形式的交换和转发层次向光网络进行了扩展的GMPLS不同于传统的MPLS,主要在于它支持多种类型的交换单元,即GMPLS除了支持分组交换,还支持TDM、波长和光纤交换等（图1）。相应的定义了以下几种类型的接口（图2）：数据分组交换接口（PSC）：该接口…     

通用多协议标签交换技术研究

通用多协议标签交换技术(GMPLS)在光交换网中具有广阔的应用前景,但对它的研究还不够深入.首先指出GMPLS与传统的标签交换技术(MPLS)在7个方面的区别,然后刻画GMPLS光网络的一般结构,对特点进行了分析,指出光IP包交换的实质是光标记的转发与交换.设计了GMPLS光网络的技术方案,对关键技术进行分析,提出了一...     

扩展RSVP-TE的路由排除策略

在实际应用中，以IP网为基础的通用多协议标签交换（GMPLS）控制平面的可靠性尚不能满足自动交换光网络（ASON）电信级的要求，针对这一情况，文章主要探讨了GMPLS信令RSVP-TE的扩展，为建立保护光通道实现路由排除功能，对排除路由对象（XRO，Exclude Route Object）和显示排除路由对象（EXRS，Explicit Exclude Route Subobject）两个对象进行了扩展。     

华为助IETFWSON标准发布

IETF标准组织近日通过华为提交的WSON（波长交换光网络）核心标准文稿（WSON架构,波长标签）成为RFC标准。这标志着智能波分传送标准正式确立,全面进入标准化时代。WSON是未来光纤传送的核心技术,基于WDM传送技术并增加GMPLS智能控制的光交换网络。     

Spectral efficient DWDM optical label/payload generation and transport for next-generation Internet

A novel optical carrier suppression and separation (OCSS) technique is used to generate spectral efficient DWDM optical labels and payload. The advantages and disadvantages of using different techniques to generate optical labels are compared. The transmission performance of the optical label and payload is experimentally and numerically investigated. These numerical and experimental results show that the optical label and payload generation and transport using the OCSS technique can be applied to wide-area metro and core network.     

On Architecture and Limitation of Optical Multiprotocol Label Switching (MPLS) Networks Using Optical-Orthogonal-Code (OOC)/Wavelength Label

To accommodate the explosive packet-based data traffic in WDM networks, intelligent optical routing and switching are required in optical transport networks. Optical multiprotocol label switching networks emerged to meet this demand. In this paper, different schemes for implementing an OMPLS network are introduced. An optical MPLS network using OOC/wavelengths as labels is proposed. Based on an all-optical code converter, the architecture of the optical core router is demonstrated. The fundamental limits on scalability of the proposed core router, namely the label capacity, and the blocking probability of the label switched path setup are investigated, and closed-form solutions are derived.     

All-optical label processor/erasure for label swapping of 12.5 Gbit/s spectrally separated bit-serial DPSK label and payload

A novel all-optical label processor/erasure for DPSK spectrally separated label and payload is demonstrated. Experimental results show the recognition of two different labels at 12.5 Gbit/s at distinct outputs, while the label is simultaneously erased allowing for a new label insertion. The low power and asynchronous label processor/erasure can be scaled to distinguish a larger number of labels, to operate at higher bit rate, and then can be potentially used in an optical label switching network.     

Label swapping versus label preserving in packet switched networks: Impact on the label space size

In recent years, switching and networking solutions exploiting all-optical nodes are gaining increasing interest to achieve the target of ultrawide-bandwidth and low-latency packet or burst processing. On the one hand, many prototypes, validated by experimental demonstration of all-optical label processing solutions, have been developed. On the other hand, the primitive available technology for performing label processing poses several constraints on the label structures; this in turn significantly impacts the traffic engineering aspects of such a network.In this paper, the label assignment problem is studied in a network that makes forwarding decision based on optical packet labels and formulated independently of any technology. Specifically, the problem of assigning labels to identify the label switched path (LSP) packets in a unique and disjoint way is defined, with the objective of optimally minimizing the label space size (i.e. number of labels, or bits, required to uniquely identify the LSPs). The network scenarios where (i) labels have local point-to-point significance (i.e. the label is swapped when traversing each node), and (ii) labels have end-to-end significance (i.e. the label is preserved along the LSP traversing multiple nodes) are both investigated. For both scenarios, labels can be uniquely identified at each node or at each node-port. The label assignment strategies for all the possible scenarios are investigated.Both theoretical and practical methods, i.e. integer linear programming formulations and heuristics, respectively, are used to assess the efficiency of the proposed label preserving solution. Numerical results show that, for a significant set of network topologies, the label space size increase experienced by networks with label preserving capabilities is limited or negligible in both per-node and per-port label identification.     

Label Stacking in Photonic Packet-Switched Networks With Spectral Amplitude Code Labels

Label stacking is used for hierarchical addressing to reduce the size of lookup tables and to increase the speed of the routing process. We propose an optical label stacking using spectral-amplitude codes (SAC) as labels to accomplish ultrafast packet forwarding. We discuss the advantages of this label architecture compared to other proposals in the literature and present experimental results. We experimentally examine two types of optical packets, one with separable SAC labels and the other one with SAC-encoded payloads. In the first case, the SAC label is a collection of spectral tones modulated at the packet rate (low rate), and the payload is on a separate wavelength modulated at the data rate (fast rate). In the second case, the payload data modulates the collection of wavelengths that constitute the code. We implement a network with two forwarding nodes, and we transmit the packets with two labels in the label stack over 80 km of fiber and measure the bit error rate (BER) after two hops. We achieve error-free transmission (BER<10 ^-9) for the packets with SAC labels and SAC-encoded payload at payload bit rates of 10 and 2.5 Gb/s, respectively. This is the first experimental demonstration of optical label stacking to our knowledge     

Enabling Technologies for Next-Generation Optical Packet-Switching Networks

The optical packet-switching network is considered to be one of the most promising solutions for end-to-end delivery of high-bitrate data, video, and voice signals across optical networks of the future. Optical label switching (OLS) technology incurs simpler extraction and processing of the labels so that the optical packets can be routed with low latency to the destinations. We have developed several key enabling technologies for integrated optical networks, including optical label generation, label swapping, optical buffering, clock recovery, and wavelength conversion. We have designed and experimentally demonstrated these enabling techniques that can provide efficient broadband services in future optical networks.     

改进型双二进制归零码信号在标记交换系统中的新应用

提出以改进型双二进制归零码(MD-RZ)信号作为标记,分别采用差分相移键控非归零码(NRZ-DPSK)信号和差分正交相移键控非归零码(NRZ-DQPSK)信号作为载荷进行正交调制的新方案.然后提出了一种从标记信号中提取和恢复时钟的简单方案.比较了背对背系统中2.5 Gbit/s的MD-RZ标记叠加到10 Gbit/s的NRZ-DPSK载荷和20 Gbit/s的NRZ-DQPSK载荷上的频谱特性,证明了MD-RZ标记占空比越大,光分组信号的频带利用率越高.采用传统的二进制强度调制-直接检测(IM-DD)系统的接收机检测得到了背对背系统中不同占空比的2.5 Gbit/s MD-RZ标记的眼图.结果表明,若采用色散补偿技术,两种光分组信号中的MD-RZ标记能够在长距离传输时克服接收端眼图的失真;当入纤功率值高于18 dBm时,占空比取值越大,MD-RZ标记的眼开度代价具有越高的传输鲁棒性.     

多跳相干探测光谱幅度码标记交换系统传输特性分析

提出了一种基于标记栈技术的两跳相干探测光谱幅度码(SAC)标记交换系统.利用仿真软件,搭建了包含两个转发节点、两个156 Mb/s光谱幅度码标记、与40 Gb/s差分正交相移键控(DQPSK)净荷的光标记交换系统.利用接收光功率与光信噪比(OSNR)分析系统传输性能,并得到结论:经两个节点传输后,标记与净荷产生的功率代价与OSNR代价均未超过3 dB.     

A novel architecture of optical code label generation and recognition for optical packet switching

A novel architecture of optical code (OC) label generation and recognition for optical packet switching (OPS) by using super structured fiber Bragg grating (SSFBG) is proposed.The OC label is generated and recognized by a label generator and recognizer,respectively.The label generator is composed of N encoders in parallel,and it can generate 2N kinds of serial optical code labels (SOCLs) for indicating 2N network routing information.The label recognizer can decode SOCLs by N decoders in parallel and provides label information to the switching control unit so that clock information is not required during the decoding process.In the switch nodes,handling of the high-speed information payload stream and the recognition of the OC label are performed in the optical domain,while processing of the routing information remains in the electrical domain.This approach could be a promising solution for an OPS network with high capacity,good quality of service (QoS),multi-service function and high security.In this experiment,we demonstrate 40Gbps 256 label optical packet switching that employs clockless SOCL processing.     

Optical Packet Switching Networks With Binary Multiwavelength Labels

We propose a network structure for routing optical packets based on binary multiwavelength labels. We resolve the main drawbacks of previously proposed optical label switching scenarios: high splitting loss and complex, expensive hardware. In our scheme, the label is mapped bit-by-bit to a selection of wavelength bins. Variable-length packets are self-forwarded via a multistage switch. This structure is scalable, high-speed, simple, practical, and low-cost, exploiting the workhorses of today's optical communications systems: arrayed waveguide gratings, distributed feedback lasers, ${rm LiNbO}_{3}$ switches, and low-speed photodiodes and electronics ($sim {hbox {100}},{hbox {MHz}}$). We also propose a solution to alleviate the sophisticated label swapping processing required in generalized multiprotocol label switching (GMPLS) networks. We time-multiplex the binary multiwavelength labels for the entire optical label switching path. We examine the performance of both schemes experimentally by verifying successful routing and error-free transmission.