大规模异构光网络智能组网技术与实验演示环境(英文)

A novel routing architecture named DREAMSCAPE is presented to solve the problem of path computation in multi-layer, multi-domain and multi-constraints scenarios, which includes Group Engine (GE) and Unit Engine (UE). GE, UE and their cooperation relationship form the main feature of DREAMSCAPE, i.e. Dual Routing Engine (DRE). Based on DRE, two routing schemes are proposed, which are DRE Forward Path Computation (DRE-FPC) and Hierarchical DRE Backward Recursive PCE-based Computation (HDRE-BRPC). In order to ...     

Energy efficient fault-tolerant multipath routing scheme for wireless sensor networks

In wireless sensor network （MSN）, reliability is the main issue to design any routing technique. To design a comprehensive reliable wireless sensor network, it is essential to consider node failure and energy constrain as inevitable phenomena. In this paper we present energy efficient node fault diagnosis and recovery for wireless sensor networks referred as energy efficient fault tolerant multipath routing scheme for wireless sensor network. The scheme is based on multipath data routing. One shortest path is used for main data routing in our scheme and other two backup paths are used as alternative path for faulty network and to handle the overloaded traffic on main channel. Shortest pat data routing ensures energy efficient data routing. Extensive simulation results have revealed that the performance of the proposed scheme is energy efficient and can tolerates more than 60% of fault.     

Virtual Path Based Routing Scheme for UWASN

Underwater acoustic sensor networks （UWASN） is a key technology for the ocean exploitation. Routing schemes specially designed for it are urgently needed. In this paper, we consider energy aware and energy balance routing schemes and aim to prolong network lifetime. By introducing the concept of ＂virtual path＂, we propose a routing scheme named virtual path based routing, which gets more global information, especially the energy information, in a local and distributed way. Simulations show that our scheme can balance the energy consumption and prolong the network lifetime with no loss of the network performance.     

Query routing mismatch alleviation architecture for P2P file lookup in MANETs

A cross-layer optimized query routing mismatch alleviation(QRMA)architecture is proposed to mitigate the problem of query routing mismatch(QRM)phenomenon between the structured peer to peer(P2P)overlay and the routing layer in mobile Ad-hoc networks(MANETs),which is an important issue that results in the inefficiency of lookup process in the system.Explicated with the representative Chord protocol,the proposal exploits the information of topologic neighbors in the routing layer of MANETs to find if there is any optimized alternative next hop in P2P overlay during conventional lookup progress.Once an alternative next hop is detected,it will take the shortcut to accelerate the query procedure and therefore alleviate the QRM problem in scalable MANETs without any assistance of affiliation equipments such as GPS device.The probability of finding out such an alternative node is formulated and the factors that could increase the chance are discussed.The simulation results show that the proposed architecture can effectively alleviate the QRM problem and significantly improve the system performance compared with the conventional mechanism.     

A two-layer recurrent Neural Network based approach for overlay multicast

Overlay multicast has become one of the most promising multicast solutions for IP network, and Neutral Network（NN） has been a good candidate for searching optimal solutions to the constrained shortest routing path in virtue of its powerful capacity for parallel computation. Though traditional Hopfield NN can tackle the optimization problem, it is incapable of dealing with large scale networks due to the large number of neurons. In this paper, a neural network for overlay multicast tree computation is presented to reliably implement routing algorithm in real time. The neural network is constructed as a two-layer recurrent architecture, which is comprised of Independent Variable Neurons （IDVN） and Dependent Variable Neurons （DVN）, according to the independence of the decision variables associated with the edges in directed graph. Compared with the heuristic routing algorithms, it is characterized as shorter computational time, fewer neurons, and better precision.     

Wireless Cooperative Mesh Network:A New Architecture for Network Convergence

The convergence of heterogeneous wireless networks is a trend in the evolution of wireless networks.A new architecture for network convergence,named Wireless Cooperative Mesh Network,is proposed to solve such emerging problems in convergence as transmission mode selection,load balancing,routing and handover.The new architecture is based on the structure of Wireless Mesh Networks (WMNs),and cooperative communication is also employed to further optimize its structure and upgrade its performance.It can thus obtain advantages of both the Mesh technology (high spectrum efficiency and dynamic self-organization) and cooperative communication (high diversity gain and high energy efficiency).The new architecture serves as an efficient solution for wireless network convergence.     

Virtual channel load-balanced routing algorithm for Torus networks

In order to improve the network performance furthermore,a routing algorithm for 2D-Torus is investigated from the standpoint of load balance for virtual channels.The 2D-Torus network is divided into two virtual networks and each physical channel is split into three virtual channels.A novel virtual channel allocation policy and a routing algorithm are proposed,in which traffic load is distributed to those three virtual channels in a more load-balanced manner by introducing a random parameter.Simulations of the proposed algorithm are developed with a SystemC-based test bench.The results show that compared with the negative first for Torus networks(NF-T) algorithm,the proposed algorithm can achieve better performance in terms of network latency and throughput under different traffic patterns.It also shows that a routing algorithm with load balance for virtual channels can significantly improve the network performance furthermore.     

Overlay networking： applications and research challenges

Overlay networking is one of the perspective solutions to today‘s Internet challenges. At basic service level, overlay networks can serve as a supplement and enhancement of existing services, such as routing and addressing. At high application level, overlay networks can be used for applications, which are difficult to deploy in existing IP architecture with some specific reasons, e.g., they need high-level information, which is hard to obtain by underlying layers. To address the heterogeneity of today‘s Internet, overlay networks provide ways to service availability and desirable performance while retaining scalability. In contrast to changing the existing network layer, overlay networks allow bootstrapping, which is most important in the development of Internet infrastructure. Various applications of overlay networking are clarified in this paper. Research challenges including routing and searching in overlay networking are also identified.     

A Framework of Information Service Platform in E-Government

For exchanging and sharing information and services in e-government, a framework of information service platform (ISP) is presented. The multi-layer architecture of the ISP is introduced. They are. user's requirement layer, business service layer, business process layer, business function layer and data layer. The lower layers are based on the architecture of web services and the upper layers are related to the institutional and organizational issues. In order to deal with the variation of user's requirements and changing environment, the matching and mapping processes with adaptive mechanism are illustrated.     

基于GMPLS的多区域／多层面网络的需求分析

主要介绍基于GMPLS的多区域／多层面网络的基本概念与功能需求，并对功能需求分成两个方面进行分析，主要讨论了在该网络体系结构下实现相应的功能需求需要对GMPLS协议进行的扩展以及引入的新机制。     

基于PCE的ASON路由技术研究

由因特网工程任务组(IETF)路径计算单元(PCE)工作组定义的基于PCE的多协议标签交换/通用多协议标签交换(MPLS/GMPLS)网络结构能有效解决多层网络中端到端的路径计算问题.文章从自动交换光网络(ASON)路由技术的发展趋势出发,根据有关PCE的RFC文档对PCE的体系结构、发现机制和策略进行了较为系统的说明,重点对PCE在ASON路由中的应用及PCE路径保护和恢复机制进行了阐述,表明PCE技术将成为ASON路由技术的首要选择.     

Resilience in GMPLS path management: model and mechanism

The recent advent of converging the IP and optical networks has necessitated the development of a generalized multiprotocol label switching framework. Resilience becomes more important than ever before in a GMPLS network since a single cut of an optical fiber may generate hundreds of link and node failures at high layers of the GMPLS architecture. In this article we briefly survey the current work regarding GMPLS recovery management, and present a new resilience-based dynamic GMPLS path management strategy. We present a simple model to represent the resilience requirements in GMPLS path management, and propose fast path management algorithms. The salient feature of the proposed approach is that it enables the paths to be dynamically selected under multiple simultaneous failure occurrences while satisfying the resilience requirement. Backup path design rules are developed, and the condition for backup path availability is derived for the special mesh-type GMPLS network. Finally, a simple example is shown to illustrate the effectiveness of the proposed resilience model and path management mechanism.     

Layer-preference policies in multi-layer GMPLS networks

We address the problem of routing Label Switched Paths (LSPs) in multi-layer networks based on the Generalized MultiProtocol Label Switching (GMPLS) paradigm. In particular, we pursue policies for choosing the appropriate layer to host a new LSP request, as we find that such layer-preference policies have significant impact on network performance. We discuss several simple layer-preference policies and we reveal why these simple policies ruin network performance in the long run. Consequently, we develop an efficient heuristics, the Min-phys-hop routing and wavelength assignment algorithm, to govern the selection of the best layer of a multi-layer network in which to host new LSP requests. We discuss the applicability of this algorithm with respect to the state-of-the-art GMPLS standards, above all, the GMPLS routing extensions to OSPF-TE. By extensive simulations, we justify that the Min-phys-hop algorithm produces close-to-optimal blocking and resource consumption under almost all possible selections of input parameters, and this is regardless of the wavelength and Optical-Electrical-Optical (OEO) conversion capability present in the network.     

GMPLS的动态路由机制研究

GMPLS由MPLS演进而来,它是MPLS向光层扩展的必然产物,路由技术是GMPLS的一项关键技术。这里简要回顾了MPLS技术,在此基础上对GMPLS中与路由相关的关键技术做了介绍,讨论GMPLS中现有的路由选择策略,论述基于GMPLS支持的对等网络模型对一种联合的网络结构及其控制平面的结构,最后提出基于GMPLS的网络中一种有QoS保证的动态路由机制。     

Hierarchical routing and traffic grooming in IP/MPLS-based ASON/GMPLS multi-domain networks

Routing, connection setup, and path computation are well-known problems in multi-domain networks, which have been largely analyzed in pure IP (packet) networks. In circuit-switched optical multi-domain networks, there remain, however, a number of routing and path computation challenges. Traffic grooming means combining a number of low-speed traffic streams so that the high capacity of each lightpath may be used as efficiently as possible, as path computation implements the core of the grooming function, it is obvious that solutions for the traffic grooming problem in optical multi-domain networks are still not sufficiently investigated. In this study we propose a methodology to address the problems of routing, connection setup, and traffic grooming in optical multi-domain networks, which adapts a two-level hierarchical routing scheme and full-mesh topology abstraction algorithm to improve routing scalability and lower inter-domain blocking probabilities; additionally our proposed methodology adapts a scheme for traffic grooming in DWDM multi-domain networks to improve the resources usage. To test our proposed methodology we propose a detailed IP/MPLS-based ASON/GMPLS multi-domain multilayer test framework.     

基于PNNI的ASON路由协议

通用多协议标签交换(GMPLS )是将多协议标签交换 /流量工程(MPLS-TE )进行光网络扩展,并被广泛接受作为自动交换光网络(ASON )控制面协议的理想选择,然而标准化组织正讨论研究将专用网网间接口( PNNI )协议用于 ASON 控制面的潜力。文中主要通过对 PNNI 的路由分层概念、 PNNI 的路由信息分发机制和 PNNI 的路径选择机制的介绍,给出 PNNI 路由的几个扩展,以适合 ASON 的路由需求。     

Applying PTF/VTF routing policies in multilayer IP/MPLS-based ASON/GMPLS multi-domain networks

The IP/MPLS-based ASON/GMPLS hybrid network architecture enables the interaction between the IP layer and the optical dense wavelength division multiplexing (DWDM) layer. This architecture makes it possible to transfer huge amounts of traffic data on DWDM networks, while supporting Internet Protocol (IP)-based service applications. Additionally, this architecture provides a unified routing scenario, which allows the dynamic routing in both the IP layer and/or optical layer. Cross- layer routing has been addressed in single domain networks scenarios, where the routing policies Physical Topology First (PTF) and Virtual Topology First (VTP) have been proposed and applied. However, applying cross-layer routing using both routing topology policies PTF and VTF has not been investigated in a multi-domain networks scenario yet. In this study, we address this issue and propose a routing scheme to establish traffic connections in the optical WDM layer and the IP layer, which makes the applicability of PTF and VTF in multilayer multi-domain network feasible.