光传送网向光分组交换网演进的策略探讨

光分组交换(OPS)是分组交换技术向光层的渗透和延伸,OPS网是未来光网络中承栽话音和数据等多种业务的理想平台.受IP业务的拉动以及目前不断发展的光交换技术的推动,OPS网络必将有着非常广阔的应用前景.文章描述了OPS传送网的分层结构以及网络组成结构,给出了近期、中期和远期3个发展阶段OPS传送网的分层参考模型,基于该参考模型,探讨了现有光传送网在3个发展阶段向OPS传送网演进的策略.     

Traffic models for slotted optical packet switched networks

Optical packet switching (OPS) has emerged as a promising architecture for the future all-optical network scenario. In order to have a successful deployment of OPS networks, several networking issues must be resolved, e.g., how to resolve contentions and how to provide Quality-of-Service (QoS) differentiation. Such networking studies often rely on teletraffic analysis in order to quantify the performance of the OPS network. In this paper, we introduce new and review existing traffic models for slotted buffer-less OPS networks. In particular, we present a novel asymmetric traffic model, suitable for studying the effects of non-uniform traffic. Optical packet switches with and without wavelength conversion are studied. Numerical evaluations and a comparison study of the presented traffic models are reported. The main contributions of this paper are to advance the field of establishing a theoretical framework for slotted OPS networks and to act as a tutorial for teletraffic engineering in such networks. http://www.item.ntnu.no/~haraldov.     

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.     

核心通信网的光分组交换

文章首先简单说明了新一代通信网需要使用分级交换的由来。接着详细叙述了光分组交换在未来光通信网的应用，包括节点结构、分组格式、输入、输出接口和一些特别重要的技术，如再生、同步、信头处理、缓冲、空间交换和波长转换等。     

Benchmarking and viability assessment of optical packet switching for metro networks

Optical packet switching (OPS) has been proposed as a strong candidate for future metro networks. This paper assesses the viability of an OPS-based ring architecture as proposed within the research project DAVID (Data And Voice Integration on DWDM), funded by the European Commission through the Information Society Technologies (IST) framework. Its feasibility is discussed from a physical-layer point of view, and its limitations in size are explored. Through dimensioning studies, we show that the proposed OPS architecture is competitive with respect to alternative metropolitan area network (MAN) approaches, including synchronous digital hierarchy, resilient packet rings (RPR), and star-based Ethernet. Finally, the proposed OPS architectures are discussed from a logical performance point of view, and a high-quality scheduling algorithm to control the packet-switching operations in the rings is explained.     

Common packet data channel (CPDC) for integrated wireless DS-CDMAnetworks

A common packet data channel (CPDC) architecture is proposed to support bursty, packet-based services in direct sequence code-division multiple-access (DS-CDMA) integrated wireless access networks. The architecture employs an asynchronous transfer mode (ATM) strategy in the forward CPDC link and a spread ALOHA-type random access strategy in the reverse CPDC link. A congestion control algorithm using base station broadcast and portable terminal random delay call reattempt is described. A performance analysis of the CPDC architecture and algorithms is carried out, and formulas for the bit error rate, blocking probability, system delay time, transmission time, and waiting time for packet data calls are derived. The interference caused by a CPDC to stream services in the network is determined, and the capacity of a CPDC is evaluated in terms of the number of packet data subscribers that can be served with a specified grade of service (GOS)     

On the design of asynchronous optical packet switch architectures with shared delay lines and converters

Optical packet switching (OPS) is a promising technology to enable next-generation high-speed IP networks. A major issue in OPS is packet contention that occurs when two or more packets attempt to access the same output fiber. In such a case, packets may be dropped, leading to degraded overall switching performance. Several contention resolution techniques have been investigated in the literature including the use of fiber delay lines (FDLs), wavelength converters (WCs), and deflection routing. These solution typically induce extra complexity to the switch design. Accordingly, a key design objective for OPS is to reduce packet loss without increasing switching complexity and delay. In this paper, we investigate the performance of contention resolution in asynchronous OPS architectures with shared FDLs and WCs in terms of packet loss and average switching delay. In particular, an enhanced FDL-based and a novel Hybrid architecture with shared FLDs and WCs are proposed, and their packet scheduling algorithms are presented and evaluated. Extensive simulation studies show that the performance of proposed FDL-based architecture outperforms typical OPS architectures reported in the literature. In addition, it shown that, for the same packet loss ratio, the proposed hybrid architecture can achieve up to 30% reduction in the total number of ports and around 80% reduction in the overall length of fiber as compared to the FDL-based architectures.     

移动分组业务迁移至IP承载网的方案研究

介绍了新型IP承载网的网络结构和接入模型,提出了一种可行的将现有移动分组业务从原IP网络迁移至新型IP承载网的方案,并保持迁移过程中全国各省移动分组业务稳定运行。     

基于QoS的3G网络系统设计与研究

为了有效地解决无线通信网络在宽带业务不断增加时产生的拥塞问题,提出了将区分服务模型应用于第三代移动通信网络以满足不同业务对QoS的需求。详细分析了区分服务模型的关键技术以及区分服务模型的系统结构,将区分服务模型和第三代移动通信分组域核心网系统结合起来,设计了支持QoS的第三代移动分组域核心网络。实验表明提出的模型较好地解决了第三代移动网络分组域核心网的QoS问题,提高了对不同业务的服务质量。     

Contribution to future metropolitan access network planning considering link failures in photonic switched networks

Photonic switching for traffic optimization in Metropolitan Access Optical Networks using technologies of optical packet/burst switching (OPS/OBS) seems to be a future-proof solution considering high capacity and the highly variable traffic in these networks. Looking for this future, we propose a study based on the analyze of survivability of traffic unconsidering protection mechanism but considering mesh and ring efficient topologies with node architecture to OPS. The results are obtained through computer modeling and simulation. The main parameters analyzed are as follows: capacity, average number of hops, packet loss fraction, and link utilization for each topology. These parameters are adopted to evaluate the performance of each topology considering failures. Minimum electronic buffering is included at node ingress (client side) to avoid packet loss in the access to the optical layer: high throughput and low latency. It is also observed that optical buffering is not necessary for adequate network performance.     

浅谈IP多媒体子系统业务平台

文章研究了3GPP在UMTSRel5、Rel6演进版本中提出的IP多媒体子系统(IMS),描述了IMS在基于分组域上提供电话和非电话业务的系统架构。IMS的提出对固网和移动网络的融合起到了很大的推动作用,研究基于IMS的统一业务平台对下一代业务平台体系架构具有一定参考意义。     

The study of QoS guarantee in the optical burst switching internet backbone

Optical switching technology can be categorized into optical circuit switching (OCS), optical packet switching (OPS) and optical burst switching (OBS). OCS is suitable for large amounts of data transmission; however, the channel utilization is inefficient when the traffic flows are intermittent. OPS can be easily adapted to any higher layer and is suitable for bursty traffic, but it requires a highly complex technology and optical buffer. The new switching paradigm, OBS, can provide higher bandwidth utilization and meanwhile avoid the complexity in OPS technology.In this paper, we investigate how the quality of service (QoS) can be guaranteed and reliable transmission can be supported in the OBS-based Internet backbone. We propose the adjustable-time-counter-based (ATCB) burst assembly and the non-real time packet retransmission mechanisms and apply them in the ingress router of the OBS Internet backbone to guarantee the quality of real time applications and lossless requirement of non-real time services. Moreover, traffic shaped is performed for real time packets in the egress router so that the real time property is preserved with a low jitter. Simulation results show that the burst blocking probability using the ATCB burst assembly is improved, compared with the time-counter-based (TCB) and burst-length-threshold-based (BLTB) mechanisms. The delay, loss and jitter of real time service conform to the QoS requirement. Meanwhile, the delay of non-real time service also falls in the acceptable range.     

The Data Vortex Optical Packet Switched Interconnection Network

A complete review of the data vortex optical packet switched (OPS) interconnection network architecture is presented. The distributed multistage network topology is based on a banyan structure and incorporates a deflection routing scheme ideally suited for implementation with optical components. An implemented 12-port system prototype employs broadband semiconductor optical amplifier switching nodes and is capable of successfully routing multichannel wavelength-division multiplexing packets while maintaining practically error-free signal integrity (BER $ ≪ {hbox{ 10}}^{ - 12}$ ) with median latencies of 110 ns. Packet contentions are resolved without the use of optical buffers via a distributed deflection routing control scheme. The entire payload path in the optical domain exhibits a capacity of nearly 1 Tb/s. Further experimental measurements investigate the OPS interconnection network's flexibility and robustness in terms of optical power dynamic range and network timing. Subsequent experimental investigations support the physical layer scalability of the implemented architecture and serve to substantiate the merits of the data vortex OPS network architectural paradigm. Finally, modified design considerations that aim to increase the network throughput and device-level performance are presented.      

面向5G业务的乡镇SPN规划及组网架构

切片分组网凭借其技术优势已成为5G业务主流传送承载网的技术之一。伴随乡镇、农村5G业务高速发展及各类5G垂直行业对5G业务的更高更广需求,前期在市区县城区域部署的SPN已无法完全满足业务需求。为满足乡镇、农村的5G业务发展需求,需考虑将SPN下沉至乡镇层级。基于乡镇5G业务发展趋势,综合考虑乡镇SPN建设条件,结合SPN架构、组网拓扑等条件,搭建乡镇SPN架构模型并深入分析获得某地市实际应用场景建设方案,为后期乡镇SPN建设提供参考和思路。     

A flexible and distributed architecture for adaptive end-to-end QoS provisioning in next-generation networks

A novel distributed end-to-end quality-of-service (QoS) provisioning architecture based on the concept of decoupling the end-to-end QoS provisioning from the service provisioning at routers in the differentiated service (DiffServ) network is proposed. The main objective of this architecture is to enhance the QoS granularity and flexibility offered in the DiffServ network model and improve both the network resource utilization and user benefits. The proposed architecture consists of a new endpoint admission control referred to as explicit endpoint admission control at the user side, the service vector which allows a data flow to choose different services at different routers along its data path, and a packet marking architecture and algorithm at the router side. The achievable performance of the proposed approach is studied, and the corresponding results demonstrate that the proposed mechanism can have better service differentiation capability and lower request dropping probability than the integrated service over DiffServ schemes. Furthermore, it is shown that it preserves a friendly networking environment for conventional transmission control protocol flows and maintains the simplicity feature of the DiffServ network model.     

Physical and logical validation of a network based on all-opticalpacket switching systems

The large growth of telecommunication traffic demand generated by multiple new applications and expected to last at least for the next decade will force telecom operators to consider offering more flexible transport services. All-optical packet switching is a powerful technique to provide this flexibility and to support in a cost-efficient way a wide range of bandwidth consuming applications. After a very brief introduction about the packet-switched network architecture studied in the framework of the ACTS KEOPS project, we describe the structure of the packet-switching node we have defined. We then move into physical and logical analysis of the network including more than 40 network sections based on 160 Gb/s throughput optical packet switching nodes could operate error free. In addition, logical simulations have proved that such networks could provide a quality of service (packet loss rate and packet transfer delay per node) compatible with a large variety of service classes. Both results validate the feasibility of the network concept and pace the way toward a flexible network based on all-optical switching techniques     

Multi-bit rate passive double star system using time-unit packet

This paper proposes a new optical access network system; the multi-bit rate passive double star (multi-bit rate-PDS) system. The multi-bit rate-PDS system passes multi-bit rate data streams between the optical service unit (OSU) and the optical network unit (ONU) using the time-unit packet (TP). This simplifies the provision of user flexibility and provides very economical network services to users. We describe the architecture and frame structure of the multi-bit rate-PDS system, and elaborate the advantage of its user accommodation. Furthermore, we show how to decide the multiplexed bit rates in the multi-bit rate-PDS system and how to realize the receiver circuit for multi-bit rate data packet streams     

Supporting packet-data QoS in next generation cellular networks

In the past few years, the Internet has grown beyond anyone's reasonable imagination into a universal communication platform. At the same time the cellular networks, with their ability to reach a person “anywhere, anytime,” have grown impressively as well. Thus the combination of mobile networks and the Internet into the so called “mobile Internet” promises to be an important technology area. The indications are clear: the cellular networks are rapidly adopting suitable network models for supporting packet data services. A key component of this packet data service model is quality of service (QoS), which is crucial for supporting disparate services envisioned in the future cellular networks. We describe the packet data QoS architecture and specific mechanisms that are being defined for multi-service QoS provisioning in the Universal Mobile Telecommunication Systems     

An extensible, programmable, commercial-grade platform for internet service architecture

With their increasingly sophisticated applications, users promote the notion that there is more to a network (be it an intranet, or the Internet) than mere L1-3 connectivity. In what shapes a next generation service contract between users and the network, users want the network to offer services that are as ubiquitous and dependable as dial tones. Typical services include application-aware firewalls, directories, nomadic support, virtualization, load balancing, alternate site failover, etc. To fulfill this vision, a service architecture is needed. That is, an architecture wherein end-to-end services compose, on-demand, across network domains, technologies, and administration boundaries. Such an architecture requires programmable mechanisms and programmable network devices for service enabling, service negotiation, and service management. The bedrock foundation of the architecture, and also the key focus of the paper, is an open-source programmable service platform that is explicitly designed to best exploit commercial-grade network devices. The platform predicates a full separation of concerns, in that control-intensive operations are executed in software, whereas, data-intensive operations are delegated to hardware. This way, the platform is capable of performing wire-speed content filtering, and activating network services according to the state of data and control flows. The paper describes the platform and some distinguishing services realized on the platform.     

A Per-Flow Based Node Architecture for Integrated Services Packet Networks

As the Internet transforms from the traditional best-effort service network into QoS-capable multi-service network, it is essential to have new architectural design and appropriate traffic control algorithms in place. This paper presents a network node architecture and several traffic management mechanisms that are capable of achieving QoS provisioning for the guaranteed service (GS), the controlled-load (CL) service, and the best-effort (BE) service for future integrated services networks. A key feature of our architecture is that it resolves the out-of-sequence problem associated with the traditional design. We also propose two novel packet discarding mechanisms called selective pushout (SP) and selective pushout plus (SP+). Simulation results show that, once admitted into the network, our architecture and traffic management algorithms provide, under all conditions, hard performance guarantees to GS flows and consistent (or soft) performance guarantees to CL flows, respectively; minimal negative impact to in-profile GS, CL and BE traffic should there be any out-of-profile behavior from some CL flows.