并行网络模拟中的远程路由计算和查找方法

提出了一种基于边界路由器的远程路由计算和查找方法，以边界路由器为核心计算远程路由信息，查找时通过路径长度比较实现最短路径的选择。该方法有效降低了远程路由表规模，提高了并行模拟器的运行效率。与PDNS相比，远程路由表规模缩减90％，初始化占用内存节省约20％，模拟运行时间减少25％。     

基于IP地址分段的DDoS路由追踪技术研究

DDoS攻击已经成为当今网络安全的最大隐患。文中提出了基于IP地址分段的DDoS路由追踪技术，分析了边界路由器IP地址重叠分段方法以及在地址重构过程中误报的产生，阐述了降低误报率的方法。最后．通过在模拟环境下，验证了该路由追踪技术误报率低、所需边界路由器少、地址重建复杂度小。     

一种自适应动态缓存策略准入控制算法

针对片上网络的死锁问题,基于虚拟网络的自适应路由算法,设计了一个完全自适应片上路由器.重点介绍了路由算法及路由器的系统结构,设计实现了一个低代价、高效的完全自适应路由器,并在2DMesh拓扑结构下对其性能进行了模拟验证.实验结果表明,该路由器实现了无死锁的自适应路由,并提高了网络吞吐量,降低了平均网络延迟.     

一种完全自适应片上路由器的设计

针对片上网络的死锁问题,文中根据所提出的完全自适应路由思想—基于虚拟网络的自适应路由算法,设计了一个完全自适应片上路由器.重点介绍了路由算法及路由器的系统结构,最终设计实现了一个高效、低代价的完全自适应路由器,并在2D Mesh拓扑结构下对其性能进行了模拟验证.实验得出该路由器实现了无死锁的自适应路由,并降低了平均网络延迟,提高了网络吞吐量.     

基于流记录的非对称路由检测

针对同时使用多个ISP接入服务的校园网,网络边界路由的错误配置导致非对称路由现象发生,提出了一种基于流记录的非对称路由检测(FARD, flow-based asymmetry routing detection)方法。该方法利用TCP面向连接的传输特性结合IP地址的归属,基于边界路由器提供的流记录数据定位网络中可能存在非对称路由的IP地址。算法基于CERNET 2个主节点的接入路由器流记录进行了验证。     

基于DynamipsGUI的网络路由优化实验设计

策略路由是网络优化的常用方法。利用DynamipsGUI搭建网络环境,配置路由策略,模拟了报文大小分别为60、500和1800三种数据报文从路由器转发时,路由器根据路由策略将数据报文从不同路径转发的过程,实验结果与设计完全一致。     

互联网BGP路由收敛问题研究现状的分析

文章重点分析了互联网边界网关协议(BGP)路由收敛问题,叙述了当前国际上对这个问题的几种解决方案,并指出了这几种解决方案所存在的问题.作者提出了自己的观点:BGP路由收敛问题与各路由器有不同的路由策略;各路由器BGP的数据更新时延不同;各链路连接失败和恢复的次序不同;路由更新消息的粒度与多方因素有关,应该找出一种综合的解决方法.     

跨域场景下的联邦路由机制设计

随着多网融合的发展,独立自治域网络之间的高效互联互通已成为一个关键理论技术问题。由于域内信息的私密性,各自治域之间不会共享相关的数据,传统的域间路由协议无法提供高效的跨域路由机制。为克服现有协议存在的不足,提出了一种基于机器学习的联邦路由机制,该机制通过各自治域的神经网络模型和参数隐式地共享域内信息,不仅可打破现存的数据孤岛问题,还可极大地减少域间信息共享所需要传输的数据量,进而降低全网路由信息收敛时延,基于该联邦路由机制,边界路由器也能够根据全网状态信息制定全局的优化路由转发策略。     

基于提前分配路径的低时延片上路由器结构

该文针对片上网络提出一种基于提前分配路径的低时延片上路由器结构(PAPR).新路由器采用提前路由计算和提前分配路径来缩短路由器流水线深度.提前路由计算为虚信道提前分配提供了可靠保障,即使在虚信道路径提前分配失败的情况下,也不影响分组在网络中的传输时延.该文提出基于缓存状态的仲裁算法BSTS(Buffer Status)综合考虑当前节点缓存信息和下游节点缓存信息,不但降低了分组等待时延,而且降低了缓存空闲的概率.仿真结果表明,新路由器能明显改善网络的时延和吞吐性能,相比采用滑动迭代轮询仲裁iSLIP(iterative Round-Robin Matching with SLIP(Serial Line Interface Protocal))算法的经典虚信道路由器,网络平均端到端时延降低了24.5％,吞吐率提高了27.5％;与采用轮询迭代RRM(Round-Robin Matching)算法的经典虚信道路由器相比,平均端到端时延降低了39.2％,吞吐率提高了47.2％.路由器硬件开销和平均功耗分别增加仅为8.9％,5.9％.     

移动IP路由策略分析

移动IP技术实现了对移动数据业务的支持,但由于存在有防火墙和边界路由器的安全限制,以及移动主机和通信对端对移动性支持与否,存在有适合不同应用范围的路由方案.文中详细讨论了各种不同路由策略及其优缺点.     

Using tunneling techniques to realize virtual routers

The evolution of the router architecture has gradually changed from a conventional architecture, which processes all functions on one operating system/processor, to a remote architecture, which can be split into a control plane and a data plane with their respective functions. The control plane is mainly responsible for the operations of the routing/signaling protocols and the data plane is responsible for forwarding the large amount of data packets. Furthermore, the remote architecture facilitates the realization of virtual routers. Virtual routers are created basically by logically splitting a routing processor in the control plane into many virtual routing units that have independent routing tables, use independent protocols, and connect to the external network through different interfaces. A virtual router with a remote architecture is more flexible and efficient than conventional routers; however, it requires an additional communication mechanism between the control plane and the data plane. We propose using existing tunneling techniques to provide a communication mechanism between the control plane and the data plane. Many design and implementation issues on the software architecture and protocol ramification are identified. We discuss solutions to these issues and successfully demonstrate a working virtual router with our proposed solutions.     

A router-assisted session tree configuration mechanism for reliablemulticast

A session tree based mechanism provides an efficient method to avoid well-known feedback implosion. However, it is not easy to configure an efficient session tree for IP multicast because it does not provide any explicit membership and routing topology information to the upper layer protocol. Incongruity between a session tree built on the transport layer and the corresponding routing tree on the network layer would incur large cost to handle control messages. This problem can be solved if a router that knows the information of routing topology can support the configuration of a session tree. Thus this letter proposed a router-assistant mechanism which minimizes the change of router functions and allows the routers to assist in providing a reliable multicast transport service     

Two Techniques for Fast Computation of Constrained Shortest Paths

Computing constrained shortest paths is fundamental to some important network functions such as QoS routing, MPLS path selection, ATM circuit routing, and traffic engineering. The problem is to find the cheapest path that satisfies certain constraints. In particular, finding the cheapest delay-constrained path is critical for real-time data flows such as voice/video calls. Because it is NP-complete, much research has been designing heuristic algorithms that solve the epsiv-approximation of the problem with an adjustable accuracy. A common approach is to discretize (i.e., scale and round) the link delay or link cost, which transforms the original problem to a simpler one solvable in polynomial time. The efficiency of the algorithms directly relates to the magnitude of the errors introduced during discretization. In this paper, we propose two techniques that reduce the discretization errors, which allows faster algorithms to be designed. Reducing the overhead of computing constrained shortest paths is practically important for the successful design of a high-throughput QoS router, which is limited at both processing power and memory space. Our simulations show that the new algorithms reduce the execution time by an order of magnitude on power-law topologies with 1000 nodes. The reduction in memory space is similar.     

一个低代价的完全自适应路由器设计

互连网络路由器是ＭＰＰ系统的关键器件，其性能优劣直接影响系统性能，本文在ｍｅｓｈ结构上，针对完全自适应器由算法实现难度较大的问题，在性能、低价和实现复杂性 进行合理折衷，给出了一个代价低、自适应性强的完全自适应路由算法ＬＣＦＡＡ，对传统的虫孔路由切换技术进行改进，提出了弹性虫孔路由切换技术，并采用基于虚通道的综合流控策略，设计了一个简洁高交的完全自适应路由器ＬＦＲ，其逻辑在ＸｉｌｉｎｘＸＡＣＴ的Ｃ     

实验性互联网中仿真路由器的配置方法

由于路由器的价格还比较昂贵，利用路由器组建实验性互联网的费用比较高，所以能够用于学生做实验的路由器几乎很少，甚至没有。为了让学生全面理解并掌握路由器的原理、作用、配置方法，可以使用计算机仿真路由器，同样可以实现路由。本文介绍了在实验性互联网络中如何用计算机仿真路由器，并阐述了路由配置方法。     

A load balancing bufferless deflection router for network-on-chip

The bufferless router emerges as an interesting option for cost-efficient in network-on-chip (NoC) design. However, the bufferless router only works well under low network load because deflection more easily occurs as the injection rate increases. In this paper, we propose a load balancing bufferless deflection router (LBBDR) for NoC that relieves the effect of deflection in bufferless NoC. The proposed LBBDR employs a balance toggle identifier in the source router to control the initial routing direction of X or Y for a flit in the network. Based on this mechanism, the flit is routed according to XY or YX routing in the network afterward. When two or more flits contend the same one desired output port a priority policy called nearer-first is used to address output ports allocation contention. Simulation results show that the proposed LBBDR yields an improvement of routing performance over the reported bufferless routing in the flit deflection rate, average packet latency and throughput by up to 13%, 10% and 6% respectively. The layout area and power consumption compared with the reported schemes are 12% and 7% less respectively.     

一个2D-Mesh上的完全自适应路由器设计

路由器在大规模并行处理机系统(MPP)中,对互连网络通信性能和系统性能发挥起着关键作用.本文根据所提出的完全自适应路由思想——基于通道方向的完全自适应路由,设计了一个2D-Mesh上完全自适应路由算法.进一步,采用了一种新的高速网络互连技术——源同步技术,最终设计、实现了一个高效、简洁的完全自适应路由器,并在Xilinx XACT的CAD工具上进行了模拟验证.     

Novel hardware architecture for fast address lookups

For every packet an IP router receives, it makes a routing decision based on the packet's destination address. The router's forwarding rate is usually limited by the rate at which it can make these decisions. We describe a new method for implementing route lookups in hardware. Our method can be implemented in the forwarding engine of a network processor or router using a small on-chip SRAM and an off-chip DRAM, and it achieves a rate of one lookup per DRAM random access time. We present our method and discuss an implementation that uses a DRAM with 64 ns random access time to give over 15 million lookups per second. Our tests show that the method performs well for realistic routing tables while using only modest amounts of memory.     

基于区分服务的边缘路由器的服务质量

Internet real-time multimedia communication brings a further challenge to Quality of Service （QoS）. A higher QoS in communication is required increasingly. As a new framework for providing QoS services, Differentiated Services （DiffServ） is undergoing a speedily standardization process at the IETF. DiffServ not only can offer classified level of services, but also can provide guaranteed QoS in a certain extent. In order to provide QoS, DiffServ must be properly configured. The traditional DiffServ mechanism provides classifier for edge router to mark the different traffic streams, and then the core router uses different Drop Packet Mechanisms to drop packets or transmit data packets according to these classified markers. When multiple edge routers or other core routers transmit data packets high speedily to a single core router, the core router will emerge bottleneck bandwidth. The most valid solution to this problem is that the edge router adopts drop packet mechanism. This paper proposes an Modified Edge Router Mechanism that let the edge router achieve marking, dropping and transmitting packets of hybrid traffic streams based on DiffServ in a given bandwidth, the core router will only transmits packets but won＇t drop packets. By the simulation of ns2, the modified mechanism ensure the QoS of high priority traffics and simplify the core router, it is a valid method to solve the congestion of the core router.     

A novel architecture of optical code label processing in parallel designed for all optical routing system

A novel architecture of optical code label routing is designed based on optical code division multiplexing techniques, which performs the data packet forwarding and processing in parallel with a way of making the label and payload encoded and decoded separately. It uses optical polarity characteristics to realize the separation of the label and payload, employs fiber Bragg grating to encode/decode the label and payload so as to process them in parallel, and makes the forwarding and routing process realized in the optical domain. In the core router, the separation of the label and payload guarantees that the switch processing only includes the short label code recognition, without processing the payload. The payload recognition is carried out in the edge router. Thus, the router can simplify the processing of encoding and decoding in the core router, accelerating the switching, and increase the throughput greatly. Moreover, the novel routing scheme not only supports the varying of data packets, transparent transmission, fine granularity switching, and so on, but also is suitable for the aggregation of data service. It is attractive for the future development of all optical routing.