智能光网中的联合路由

在IP／MPLS智能光网络中的LSP路由分为独立路由和联合路由两类。由于综合考虑了光层和IP层的可用资源信息和拓扑信息，联合路由能够提供比独立路由方案更高的资源利用率。文中提出了联合路由算法的设计目标，综述了联合路由算法的研究现状，并给出了下一步的研究方向。     

MA5200G助力运营商打造精品城域网

1 引言 随着IP宽带路由技术的不断发展和业界多年对IP宽带网上实际应用的探讨,运营商的城域网已逐步成为未来电信多业务的承载网,并确定了以大容量、高带宽、高处理能力的路由器为承载核心,构建物理和逻辑层次清晰的三层路由网络(IP城域网)和二层宽带接入网的网络架构.在这个网络优化和多业务转型的过程中,IP核心网络"边缘智能化"将成为实现运营商网络和业务转型的关键.     

IP路由与交换

路由技术是网络互连的基础，IP交换是二层交换技术加三层转发技术。本文描述了交换与路由的基本概念、IP路由协议、组播路由以及IP交换类型和快速IP交换。     

智能光网中的联合路由

在IP/MPLS智能光网络中的LSP路由分为独立路由和联合路由两类。由于综合考虑了光层和IP层的可用资源信息和拓扑信息,联合路由能够提供比独立路由方案更高的资源利用率。文中提出了联合路由算法的设计目标,综述了联合路由算法的研究现状,并给出了下一步的研究方向。     

ASON域间路由的特点与应用

自动变换光网络（ASON）是传送网发展的趋势，而路由技术是整个ASON的核心技术之一。主要讨论了ASON域间路由的特点及其在网络中的应用。首先介绍了域的概念和网络的分缀与分层；然后讨论了ASON路由与IP路由的不同之处；接着讨论了ASON域间路由的特点，并对几种路由协议进行了分析，阐述了多层网络的路由问题；给出ASON域间路由在网络中的不同应用方式。     

IP over WDM网络路由机制研究

对于IP over WDM成功应用的一个关键因素，是其路由机制能否提供象多层体系结构那样具有快速路由功能的健壮性，本文对IP over WDM网络在不同组网模型下的路由机制进行了深入的分析和研究。     

基于增强学习的协作主动路由信息交换机制

分组交换网是当今全球通信基础设施的重要部分，IP网络终将与其他网络相互融合，演化成为新一代网络技术，现有路由协议的实现是单一的，并且将数据库、最优路径计算和网络状态分发机制捆绑在一起。主动路由选择是一个把上述困难作为目标的新路由选择策略。主动路由选择机制被设计用来提供基于用户服务模式的路由选择。本文提出了一种基于增强学习的协作主动路由信息交换机制，主动路由代理获悉网络基础结构不同属性的当前状态，并在这个基础上建立和维护路由表，实现主动路由选择机制。     

IP/WDM网络生存性策略分析

本文在研究网络生存性基本问题的基础上，分析IP层中缩短IP动态路由恢复时间的改进策略和基于MPLS的生存性策略；同时，对不同方案的资源利用率和保护倒换时间进行了比较；最后探讨了多层生存性协调可能遇到的挑战。     

分组传输网路由端口的IP自动分配方法设计与实现

在分组传输网设备首次部署开通组网时，分组传输设备之间运行的静态路由协议或动态路由协议都需要分组传输设备互联路由端口之前存在路由端口IP地址。当首次开通组网的网络规模巨大时，需要网络管理员对网络设备路由端口IP进行详细的规划和配置。该过程一旦出现异常或错误将导致全网的路由协议运行出现故障。故设计并实现基于二层组播报文的路由端口IP自动分配协议和具体实现的方法。通过该方法，可有效的实现大规模组网环境下的各分组传输设备之间路由端口的IP地址的自动分配。可有效降低网络管理员对分组传输设备的配置，提高网络设备开通的效率。     

思博伦通信发布下一代IP路由器测试系统

近日，思博伦通信宣布其TRT交互式路由测试系统能够评估综合性的IP路由网络中的音频、视频和数据服务。网络设备制造商通过使用TRT交互式路由测试系统能够仿真复杂的网络情况、判定被测设备情况、支撑复杂的IP路由，对网络设备进行测试。TRT交互式路由测试系统可以评估与应用相关的IP服务质量，允许运营商评估和部署复杂的路由技术，例如第2层和第3层MPLS VPN和组播流媒体。     

基于自由分层的通道区布线算法

本文在分析线网之间关系的基础上提出了自由分层条件下的通道区布线模型:同层限制图Gs,相交图Gi,基于这一模型,分析了二层布线条件下对线网分层和布线序的基本限制,导出了分层的基本原则,在此基础上,分析了线网可Overlap的性质和条件,从总体分析的思想出发,提出了直接以完成布线通道区所需面积最小化为目标的分层布线算法,实验结果表明,通道区布线面积和通孔的致目比基于横竖分层的布线算法有较大减少,对于Deutsch′s diffjcult example,该算法获得18个track解。     

A Bandwidth Guaranteed Integrated Routing Algorithm in IP over WDM Optical Networks

In this paper, we have developed an integrated online algorithm for dynamic routing of bandwidth guaranteed label switched paths (LSPs) in IP-over-WDM optical networks. Traditionally, routing at an upper layer (e.g., IP layer) is independent of wavelength routing at the optical layer. Wavelength routing at the optical layer sets up a quasi-static logical topology which is then used at the IP layer for IP routing. The coarse-grain wavelength channels and the pre-determined virtual topologies with respect to some a priori assumed traffic distribution are barriers to efficient resource use and inflexible to changing traffic. We take into account the combined knowledge of resource and topology information at both IP and optical layers. With this added knowledge, an integrated routing approach may extract better network efficiencies, be more robust to changing traffic patterns at the IP layer than schemes that either use dynamic routing information at the IP layer or use a static wavelength topology only. LSP set-up requests are represented in terms of a pair of ingress and egress routers as well as its bandwidth requirement, and arrive one-by-one. There is no a priori knowledge regarding the arrivals and characteristics of future LSP set-up requests. Our proposed algorithm considers not only the importance of critical links, but also their relative importance to routing potential future LSP set-up requests by characterizing their normalized bandwidth contribution to routing future LSP requests with bandwidth requirements. Moreover, link residual bandwidth information that captures the link's capability of routing future LSPs is also incorporated into route calculation. Extensive simulation was conducted to study the performance of our proposed algorithm and to compare it with some existing ones, such as the integrated minimum hop routing algorithm and the maximum open capacity routing algorithm. Simulation results show that our proposed algorithm performs better than both routing algorithms in terms of the number of LSP set-up requests rejected and the total available bandwidth between router pairs.     

Packet forwarding

A packet network is viewed as consisting of two major interacting layers: a lower layer responsible for the determination of a set of paths that can be used to carry packet flows, and an upper layer responsible for actually sending the flows over these paths, on a per-packet basis. A systematic review is provided of the various techniques that can be used to perform the actual packet-by-packet routing operation at the upper layer, called the packet forwarding function. The function components of a routing system and its characteristics (responsiveness to changes in network state and degree of centralization) are discussed. Five routing techniques are then examined, namely source, directory, destination, global-path, and channel-link-path routing     

Cooperation of Network and Service Layer in Mobile Ad hoc Networks

In this article, we investigate how a service discovery protocol at the service layer in Mobile Ad Hoc Networks can be improved, by utilizing routing information from the network layer. We consider in this article proactive routing protocols as basis for the underlying routing mechanism, and focus on the optimization of proactive service discovery protocols. First we introduce a general framework, enabling the cooperation of service layer and network layer, and then we propose the optimization scheme. The performance evaluation done by simulation shows that the proposed cooperation scheme can optimize the service discovery protocol, i.e. reduce the communication cost of service discovery, by utilizing routing table and topology information.     

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.     

Adaptive Routing Strategies in IEEE 802.16 Multi-Hop Wireless Backhaul Networks Based On Evolutionary Game Theory

The high frequency segment (10-66GHz) of the IEEE 802.16 standard seems promising for the implementation of wireless backhaul networks carrying large volumes of Internet traffic. In contrast to wireline backbone networks, where channel errors seldom occur, routing decisions in IEEE 802.16 networks are conditioned by wireless channel impairments rather than by congestion, exclusively. This renders a cross-layer routing approach between the routing and the physical layers more appropriate during fading periods. In this paper, an adaptive cross-layer routing scheme is presented based on the selection of the most reliable path in terms of packet error ratio (unipath routing). The paper argues that routing Internet traffic through wireless backhaul networks is modeled more realistically employing evolutionary rather than conventional game theory. The stability of the proposed routing algorithm is proven and the dependence of the speed of convergence on various physical layer parameters is investigated. Is is also shown that convergence may be further accelerated by increasing the amount of information from the physical layer, specifically the physical separation between the alternative paths provided to the routing layer.     

A routing layer based approach for energy efficient service discovery in mobile ad hoc networks

Service discovery can be greatly enhanced in terms of efficiency, both regarding service discoverability and energy consumption, by piggybacking service information into routing messages. Thus, service discovery does not generate additional messages and a node requesting a service, in addition to discovering that service, it is simultaneously informed of the route to the service provider. We extended the Zone Routing Protocol in order to encapsulate service information in its routing messages. Our extended protocol, E‐ZRP, may be seen as a representative of routing layer protocols providing service discovery functionality. Simulations demonstrate the superiority of this routing layer‐based service discovery scheme over that of a similar, but application layer based service discovery scheme. In order to have a thorough evaluation of our approach we introduced a new metric, called Service Availability Duration (SAD), which characterizes the ‘quality’ of discovered services and experimentally examines the implications of network density and node mobility on the availability of services discovered with E‐ZRP, as a typical representative of routing layer based service discovery protocols. Copyright © 2008 John Wiley & Sons, Ltd.     

基于跨层网络编码感知的无线传感器网络节能路由算法研究

编码感知路由可以发现路由中的网络编码机会,减少数据传输次数,提高网络吞吐量,是近年来路由算法研究的一个热点.当前编码感知路由存在编码条件失效、未考虑节点能量的问题,不适合直接应用于无线传感器网络.本文提出基于跨层网络编码感知的无线传感器网络节能路由算法CAER (Cross layer coding Aware Energy efficient Routing).提出并证明了修正后的网络编码条件,以解决编码条件失效问题.基于跨层思想,将网络编码感知机制与拓扑控制、覆盖控制结合,挖掘潜在编码机会.提出综合考虑节点编码机会、节点能量的跨层综合路由度量CCRM (Cross layer Coding aware Routing Metric).仿真结果表明,相比现有编码感知路由,CAER能够提高网络编码感知准确性,增加网络编码机会数量5%~15%,延长网络生存时间8%~12%.     

一种带权动态调整的总体布线算法及其实现

本文对现有的总体布线方法及宏单元阵列总体布线问题进行了详细分析,提出了一种基于带权动态调整思想的适合于宏单元阵列一层半和双层版图模式的总体布线算法,其目标是合理地利用已确定的布线区域,使各线网均匀地分布在芯片上,获得尽可能高的布通率。     

End-to-end throughput improvement for single radio multi-channel multi-path wireless mesh networks: a cross layer design

The distinguished feature of fixed backbone nodes in the wireless mesh networks (WMNs) can be utilized to design an efficient cross layer which cooperates routing and scheduling schemes for increasing end-to-end throughput. With only single radio nodes, by well designing the scheduling and routing schemes for multiple paths, we show that WMN can gain more throughput and reduce communication interference. Much of recent work has focused on those issues applied for “multi-channel, multi-path” environment using multi-radios that is costly and much more complex for implementation. Also, almost all of the proposals work on layer 2 or layer 3 separately that cannot support each other in performing efficiently. Instead, our paper introduces a cross-layer design with new routing algorithm that can balance the numbers of multi-paths and the needed transmission data in each communication session. We also propose a new channel scheduling and queuing models in MAC layer compatible with routing scheme and define a threshold with an effective algorithm to choose the optimal number of disjoint paths for routing scheme. The simulation results show that our multi-path routing scheme performs better than previous proposals in term of throughput improvement which can directly reduce the time of each communication session, especially in case of big size data transmission.