聚合组播路由并行查找算法

目前,组播主干网的核心路由器速率已经达到2.5Gbps～10Gbps,这一速率要求核心路由器每秒能够转发几百万乃至上千万个以上的分组.分组转发的重要一步就是查找路由表,因此快速的路由查找算法是实现高速分组转发的关键.为获取高性能组播路由查找算法,利用位图压缩技术,结合组播路由转发表的特点,设计出一种聚合组播路由并行查找算法,最后在IXP2800网络处理器模拟环境下对算法性能进行测试,达到了OC-192的线速转发性能.该算法适用于各种多线程结构处理器,具有较高的参考价值.     

城域网汇聚交换式路由器——D-Link DES-8000/8100

DES-8000/8100是D-Link推出的16/8槽模块化、高性能的城域网汇聚交换式路由器。该产品采用基于(专用集成芯片)的分组处理器,每端口都实现L2/L3/L4线速交换,可以提供极高的端口密度以及线速路由和交换功能;全面支持基于标准的路由交换协议,保证了与城域网核心路由器的互连互用性;具有强大的网络访问和数据中心流量汇聚功能,可汇聚TDM或以太网传输,并通过POS、ATM或万兆以太网上连至城域网核心层。产品介绍主要性能:基于硬件的精确到K比特的速率限制技术,可按要求提供带宽 IP路由,提供单播和组播功能,提供每个线路卡上硬件的…     

MPLS网络中的可扩展QoS组播研究

MPLS网络中的服务质量组播面临着组播路由状态的可扩展性、服务质量支持困难等瓶颈.针对这些问题,提出一种基于子树共享的新型MPLS服务质量组播方案.本文的贡献有:提出一种组播组到组播分发子树的映射算法,将多个组映射到同一颗子树,以共享的子树为基础构造完整的组播分发树,从而有效地减少MPLS核心网络中的路由状态;将服务质量的考量引入组播分发树的构造过程中,使新的方案能够支持服务质量组播;提出一种简单方便的子树共享实现机制.模拟结果表明,基于子树共享的新型MPLS服务质量组播方案能够有效地减少组播路由状态并提供多种服务质量控制的能力.     

一种基于模拟退火方法的多约束QoS组播路由算法

研究了带宽、时延及时延抖动约束最小代价的QoS组播路由问题,提出一种利用模拟退火方法解决该问题的QoS组播路由算法SABDMA。该算法通过选择合适的模拟退火参数迭代求解,以获得满足QoS约束的最小代价组播树。同时,为避免搜索区域的扩大和计算时间的增加,根据时延和时延抖动的关系,提出采用“路径交换”策略在可行解范围内构造邻域集。仿真结果表明该算法具有可行、稳定、收敛快的特点;能根据组播应用对QoS的限制要求,有效地构造代价较低的组播树,具有较强的实时性。     

组播路由器线速转发机制的设计及Linux实现

设计和实现路由器中一种基于Linux的组播线速转发机制:采用类似单播的第三层交换技术----组播第三层交换技术和采用软、硬件相结合的方案,实现软、硬件的接口,讨论软、硬件协同工作中存在的隧道问题并给出解决方案。该总体方案及实现已应用于实际高速宽带路由器的研制与开发项目中。     

基于WMPLS的无线自组网组播路由机制

将多协议标签交换(MPLS)技术与无线自组网组播机制相结合可以把MPLS在分组转发以及支持服务质量、流量工程等方面的技术优势引入到无线自组网组播路由协议设计中,具此提出了一种基于MPLS技术的组播协议设计方案——标签交换转发组播协议(Label-Switching Forwarding multicast routing protocol,以下简称LSF组播协议)。     

一种公平分配代价的组播路由算法

本文提出了一种公平分配代价的组播路由算法 DFC_ DCMT- -分布式公平分配代价的延迟受限组播路由算法 ,该算法在优化 tree- cost的条件下 ,能够计算出满足延迟限制的、各目的节点公平负担网络代价的点到多点的组播路由树 .本文还给出一种近似算法 ,可减少节点间交换的信息量 ,同时在一般情况下仍保持各目的节点公平负担网络代价 .     

支持QoS的层次组播路由算法框架QHMR

Internel规模的迅速扩大使QoS组播路由的复杂性增加．为此，该文提出了支持QoS的层次组播路由算法框架QHMR(QoS-based Hierarchical Multicast Routing)．在HMR(Hierarchical Multlcast Routing)层次划分的基础上，QHMR对网络的拓扑结构、带宽和组播树分布信息三者的聚集方法进行了定义，并设计了适用于层次网络的支持QoS的组播路由算法．实验结果表明，QHMR能显著减少路由器维护的信息以及路由器之间交换的协议分组，具有良好的可扩展性；同时，较之平面QoS组播路由。QHMR能够得到较理想的路由成功率和组播树代价。     

IP／DWDM光因特网中一种基于人工免疫算法的QOS组播路由算法

本文提出了一种IP／DWDM光因特网中基于人工免疫算法的QoS组播路由算法，当QoS组播请求和需求区间给定时，能够找到一棵基于QoS的柔性费用近优组播路由树。该算法基于人工免疫算法构造QoS组播路由树，并基于波长图对树进行波长分配，将路由和波长分配集成到一个过程中，同时考虑了负载平衡。仿真结果表明，算法为IP／DWDM光因特网中的组播应用构造的QoS组播路由树是可行和有效的。     

DES-3326神州数码三层千兆交换机

神州数码网络公司日前针对中小企业用户推出了一款性价比极佳的三层千兆交换机 DES－ 3326。 　　作为三层交换机 , DES－ 3326交换机提供了基于硬件的 ASIC的二层和三层线速 IP路由速率、协议域过滤和检察功能,甚至可提供第四层交换。 DES－ 3326前面板具有 24个固定 10/100BASE－ TX自适应 MDI/MDIX端口和 2个千兆以太网端口。提供了第二层的包交换,背板带宽为 8.8Gbps,支持 8K MAC地址、支持 16MB包缓冲区、支持广播风暴控制、支持 2层组播,并集成了 IP路由和 QoS功能;作为三层交换机,其路由功能强大,线速 IP包…     

群组集线器多级多平面自路由交换模型

基于多级多平面交换通用架构,提出一种群组集线器Banyan类多级多平面自路由交换模型。采用单元状态描述分路器、合路器和交换单元,群组集线器下的Banyan类网络描述单个交换平面,比特置换描述级间互连,导向传输描述自路由特性。基于该模型推导多种Banyan类交换网络的导向传输特性和阻塞率迭代算法。对该模型进行仿真实验,结果表明该模型在低负载强度的情况下,时延低于BG-CRRD调度算法,在高负载强度的情况下,其阻塞率高于10–2,导致时延的增加。     

Design and performance evaluation of the ATM multicast shuffleout switch

This paper describes a proposal of a multicast ATM switch whose interconnection network is the same as in the Shuffleout switch architecture, that is a multistage arrangement of switching elements in which the self-routing is accomplished by shortest-path and deflection routing. Packet replication is accomplished by means of a functionality added to each switching element that is therefore able not only to replicate the multicast packets as they go through the network but also to route the single copies to each addressed outlet. By suitably engineering the number of stages, the network is able to generate the total number of requested copies per slot within the target packet loss probability. An enhanced version is also discussed that is capable of limiting the packet replications per slot, so as to obtain the desired traffic performance with less network stages.     

基于三层交换的VLAN技术在校园网中的应用

基于三层交换的VLAN划分使网络以子网内线速交换和子网间的线速路由来达到线速通信。因此,三层交换和VLAN技术已成为构建大中型校园网的有效解决方案。在简述这种解决方案优点的基础上,通过组建校园网的实例,探讨了利用三层交换和VLAN技术组建一个可伸缩智能化校园网的过程,表明这种技术对提高校园网络安全性和校园网络管理性的积极作用。     

Survey of Unicast and Multicast Scheduling Algorithms for High Speed Input Queued Switch with Crossbar

The performance of ATM switches are mainly influenced by switching fabric and scheduling algorithms. Input buffered switches have the strong advantage of efficient crossbar usage. This paper presents an input-queued crossbar switches fabric supporting high speed switching, analyzes the scheduling algorithms for unicast trafficts and multicast traffic based on virtual output queueing (VOQ).Focusing on their performance issues, some typical schedulers are compared.     

Algebraic analysis of the topological properties of a banyan network and its application in fault-tolerant switching networks

In this paper, we introduce abstract algebraic analysis of the topological structure of a banyan network, which has become the baseline for most switching networks. The analysis provides the following key results: (1) The switching elements of a switching stage are arranged in order, that is, each stage of a banyan network consists of a series of a cyclic group. (2) The links between switching stages implement a homomorphism relationship in terms of self-routing. Therefore, we can recover the misrouting of a detour fault link by providing adaptive self-routing. (3) The cyclic group of a stage is a subgroup of that of the next stage, so that every stage and its adjacent stage make up a factor group. Based on this analysis, we introduce a cyclic banyan network that is more reliable than other switching networks. We present mathematical analysis of the reliability of the switching network to allow quantitative comparison against other switching networks.     

一种新型的联合单播/组播的两级交换结构*

高速交换结构的设计中一般很难以较低的复杂度实现其对组播业务的支持。提出一种联合单播/组播的两级交换结构TSSIUM,该结构通过对Crossbar结构级联一个组播合路结构实现,因此可以极低的复杂度即可实现对组播业务的支持。理论分析和实测数据均表明,该结构在容许的通信量下可以达到100％的吞吐率。     

一种新型的联合单播/组播的两级交换结构

高速交换结构的设计中一般很难以较低的复杂度实现其对组播业务的支持.提出一种联合单播/组播的两级交换结构TSSIUM,该结构通过对Crossbar结构级联一个组播合路结构实现,因此可以极低的复杂度即可实现对组播业务的支持.理论分析和实测数据均表明,该结构在容许的通信量下可以达到100%的吞吐率.     

ATM工作组交换机的设计与实现

本文给出了一种ATM工作组交换机的硬件体系结构,介绍了系统的各种功能模块,详细讨论了交换结构,交换原理和多播实现等问题。     

基于二进制寻路法和多Omega网络的自路由无阻塞多级网

提出了一种可以无阻塞地传输其输入与输出间任意多播信号的新型自路由无阻塞多级网。该网络采用了循环重建法,以二进制扩散概念为基础。它由一个二进制扩散网络和两个二分之一大小的多播路由网络循环构建而成。多播信号由第一个Omega网复制并二分扩散到输出端口,进入N×N的Omega×Omega-1网络,再进入紧随其后的N/2×N/2的Omega×Omega-1网络……。每个Omega×Omega-1网络负责依照目的地址的有效标志位将输入置换到输出的上半部分和下半部分,再分别进入上下两个子Omega×Omega-1网络中做同样的处理,如此类推,直到全部地址有效位处理完毕,从而完成自路由无阻塞的多播传输。由于各大小不等的Omega×Omega-1网络皆可并行设置和并行路由,故此种新型多Omega网络的设置时间为O(NlogN),路由时间为O(log2N),硬件代价则为O(Nlog2N)。它比现行已知的多播网络设计具有较优的代价。     

A method to evaluate the spatial extensibility of a switching unit and network

Switching units and networks have been analyzed as extensible fabrics,mostly in terms of their scheduling algorithms.The traditional literature on switching extensibility has provided complexity theory only relating to the total numbers of inputs(or outputs)and exchange lines.This paper analyzes switching extensibility in terms of not only the scheduling algorithm and also the fabric itself.It is found that determining extensibility from soft complexity related to the number of inputs(or outputs)of the scheduling algorithm and the fabric extensibility in previous studies without quantization is a flawed conception.A method is thus proposed to express the spatial extensibility of a switching unit or network in terms of the connections of a switching resource and capacity.The method calculates parameter ES(the efciency of switching)of an m×n switching unit and obtains two functions of the switching unit to describe spatial extensibility along with the number of unilateral inputs or outputs.It is found that the range of ES is(0,1]and three types of switching unit and two types of crosspoint networks have ES=1.ES is calculated for banyan,Clos,parallel packet,fully interconnected and recirculation switching networks.The ES value for the banyan switching network is larger than that for other networks,and switching networks are classified into three types that have absolute/linear/denied spatial extensibility according to the limES value.It is demonstrated that a switching network has the largest ES value when it contains only the five types of switching unit for which ES=1.Finally,a group-switching-first self-routing banyan switching network with lower blocking probability and time delay is deduced,and the ES method is contrasted with two other methods of evaluating spatial extensibility in terms of their mathematical expressions and intuitive graphics,for the five types of switching network listed above.