三维片上网络内核测试

片上网络是一种新兴的大规模集成电路的设计方法.片上网络的测试包括对内核、路由器和通信通道的测试.本文主要提出了一种新的片上网络内核测试方法.该方法通过重用片上网络通信结构,采用基于单播的多播数据传递方式,以及一种无死锁的完全自适应路由方法来传递测试数据,显著地提高了通信效率,提升了测试的并行性,降低了测试成本.     

SoC设计中的片上通信体系结构研究

以超深亚微米工艺和IP核复用技术为支撑的系统芯片(SoC)技术,是目前超大规模集成电路和嵌入式电子产品设计的主流.SoC中各IP核之间的片上通信体系结构是SoC设计关键技术之一,同时对SoC的性能起着至关重要的作用.提出一种SoC中的混合片上通信体系结构,该体系结构将传统的共享总线与片上网络相结合,既保留了片上共享总线面积小的优点,又具有片上网络的并行通信的优点.此外,该混合片上通信还可以扩展到二维网络.     

WiNoC中无线通信拥塞与故障感知的容错路由算法

在无线片上网络中,无线通信拥塞和故障对整个片上网络的通信效率具有严重影响.为此本文提出了一种针对无线通信拥塞和故障的容错路由算法,首先设计了无线通信拥塞和故障感知模型,该模型能够感知无线节点通信对的拥塞和故障信息,并对其编码发送给子网中的路由器;然后子网中的路由器根据接收到的无线节点通信对状态信息,判断数据包是否使用无线传输.实验表明,本文方案相较于对比对象能够在较小的额外面积、功耗开销下,保证较低的网络延迟和较高的网络吞吐率,并对无线节点通信对的永久性故障具有良好的容错能力.     

基于云进化算法的3D NoC测试端口优化选择

针对于三维片上网络测试时,如何选择测试端口以提高测试效率的难题,采用基于云模型的进化算法对三维片上网络测试端口进行位置寻优,并对IP核的测试数据进行合理分配,在测试功耗约束条件下,以重用片上网络作为测试访问机制,基于XYZ路由算法和非抢占式测试调度方式,对三维片上网络IP核实施并行测试,以提高测试效率。研究结果表明,该方法可对测试端口的位置及组合方案进行精确寻优,且有效减少了测试时间。     

片上网络通信架构的BIST测试方法

为了保证NoC(network on chip,片上网络)中IP核之间的正确通信,需要对片上网络通信架构进行测试。本文针对Mesh NoC的功能测试,提出了一种测试通信架构的BIST(built-in self test,内建自测试)方法。该方法在NI(network interface,资源网络接口)中添加BIST模块TPG(test pattern generator,测试向量产生器)和TRA(test response analyzer,测试响应分析器),利用TPG产生测试数据,TRA分析测试响应,来实现通信架构的测试过程。实验结果表明,该方法在增加面积开销较小的情况下,不仅降低了测试成本,还降低了测试时间。     

NoC_MPSim:基于片上网络通信架构多核仿真平台

实现了一个用于探索基于片上网络通信架构多核系统设计空间的可配置仿真平台--NoC_MPSim.该平台包含处理器工具链、平台自动化配置脚本以及一个包含处理器、网络适配器以及多种路由器的RTL模型库,可根据用户输入的系统配置信息自动生成周期精确的多核仿真系统.针对片上网络通信架构的特征,定义了基于该通信架构的多核系统的高层次通信抽象模型,并借鉴并行机中的消息传递机制,提出了一种可有效隐藏网络乱序的并行编程模型及其通信原语,并完成其所需要的软\硬件建模.应用提出的编程模型,实现了MUSIC算法基于四核仿真系统的分布式并行计算,并经实验得到该并行MUSIC算法在该系统中加速比可达2.6.     

基于自适应遗传算法的无线激光通信网络负载均衡成簇算法

由于无线激光通信网络吞吐量低、节点传输延时高和存在分组丢失率多等问题，提出基于自适应遗传算法的无线激光通信网络负载均衡成簇算法。利用AGCH算法对无线激光通信网络节点进行分组和成簇，从中取得簇头节点，构建资源调度模型，利用该模型对簇头节点中的资源进行分配调度，采用自适应遗传算法对建立的模型进行求解，以此提升无线激光通信网络负载均衡效果，实现无线激光通信网络负载均衡。实验结果表明，通过对该算法进行网络吞吐量测试、节点传输延时测试和分组丢失率测试，验证了该算法的有效性强、实用性高。     

一种片上网络路由测试方法研究

对片上网络路由器的结构进行了分析,建立了相应的故障模型.针对此故障模型结合内建自测试,提出了一种基于量子遗传算法的测试矢量传递路径寻优方法.该算法具有收敛速度快,精度高等优点.最后通过对测试故障覆盖率和测试时间进行分析表明这种测试方法具有较高的故障覆盖率、较少的测试时间.     

片上网络存储器的BIST电路设计

片上网络（Network-on-Chip ,NoC）作为解决片上系统存在的问题而提出的一种解决方案,正受到越来越多的关注,测试技术是NoC设计工作的重要组成部分。该设计针对NoC系统中SRAM存储器模块,研究了SRAM的故障模型,建立了片上网络通信架构的功能模型,复用片上网络作为测试存取路径,设计完成了基于M arch C＋算法的BIST电路设计。该方案采用Verilog语言完成设计,并且在基于FPGA的NoC系统平台上实现了对SRAM的测试。实验结果表明,在面积开销增加较小的情况下,该方法具有较高的故障覆盖率。     

片上网络容错路由算法分析和评价

片上网络技术是借鉴并行分布式计算机及传统计算机网络的概念解决片上多核系统的通信问题.片上网络代替片上总线通信,解决了片上总线结构所引起的可扩展性、效率、面积、功耗等问题.然而,片上网络在数据传输过程中可能由于各种原因产生故障,因此片上网络可靠性研究是当前一个研究热点.首先总结了片上网络故障分类,比较和分析了当前片上网络...     

Multicast-enabled network-on-chip routers leveraging partitioned allocation and switching

Multicast on-chip communication is encountered in various cache-coherence protocols targeting multi-core processors, and its pervasiveness is increasing due to the proliferation of machine learning accelerators. In-network handling of multicast traffic imposes additional switching-level restrictions to guarantee deadlock freedom, while it stresses the allocation efficiency of Network-on-Chip (NoC) routers. In this work, we propose a novel partitioned NoC router microarchitecture, called SmartFork, which employs a versatile and cost-efficient multicast packet replication scheme that allows the design of high-throughput and low-cost NoCs. The design is adapted to the average branch splitting observed in real-world multicast routing algorithms. Compared to state-of-the-art NoC multicast approaches, SmartFork is demonstrated to yield high performance in terms of latency and throughput, while still offering a cost-effective implementation.     

Multicast-Kommunikation im Internet

The Internet supports group communications by its multicast concept. Several Internet protocol extensions and new protocols have been developed in order to realize multicast in the Internet. This paper focuses on the IP multicast architecture, in particular on the IP multicast extensions and the corresponding multicast routing protocols. The IP multicast model has significant impacts on the underlying network technologies and on the transport protocols and applications on top of IP. These impacts are also discussed in the paper.     

接口标记容错路由算法

随着片上系统(SoC)集成度的不断提高,IP核之间的通信故障成为亟待解决的问题,片上网络(NoC)是解决SoC通信问题的有效途径。容错路由算法是NoC设计中的关键技术,对NoC的通信效率有重要影响。在Valiant随机路由算法和源路由算法的基础上,提出了一种接口标记容错路由算法。该算法吸取了Valiant随机路由算法能平衡网络负载、降低拥塞概率的优良性能与源路由算法中路径不需要计算与查找的特点,减小了传输时延,提高了路由器的利用率。     

A reliable multicast framework for light-weight sessions andapplication level framing

This paper describes scalable reliable multicast (SRM), a reliable multicast framework for light-weight sessions and application level framing. The algorithms of this framework are efficient, robust, and scale well to both very large networks and very large sessions. The SRM framework has been prototyped in wb, a distributed whiteboard application, which has been used on a global scale with sessions ranging from a few to a few hundred participants. The paper describes the principles that have guided the SRM design, including the IP multicast group delivery model, an end-to-end, receiver-based model of reliability, and the application level framing protocol model. As with unicast communications, the performance of a reliable multicast delivery algorithm depends on the underlying topology and operational environment. We investigate that dependence via analysis and simulation, and demonstrate an adaptive algorithm that uses the results of previous loss recovery events to adapt the control parameters used for future loss recovery. With the adaptive algorithm, our reliable multicast delivery algorithm provides good performance over a wide range of underlying topologies     

WDM光网络中光层组播技术的研究

本文分析了光层组播原理。在物理层实现组播 ,使该技术在整个互联网实施实时交互音像通信和有效抑止“电子瓶颈”效应有着重大作用。文中对两种不同结构具有光层组播的OXC进行了分析比较。并且对WDM光网络中的无阻塞组播通信波长满足条件进行了分析探讨。     

OMAC: A new access control architecture for overlay multicast communications

Multicast communications concern the transfer of data among multiple users. Multicast communications can be provided at the network layer—an example is IP multicast—or at the application layer, also called overlay multicast. An important issue in multicast communications is to control how different users—senders, receivers, and delivery nodes—access the transmitted data as well as the network resources. Many researchers have proposed solutions addressing access control in IP multicast. However, little attention has been paid to overlay multicast. In this paper, we investigate the access control issues in overlay multicast and present OMAC: a new solution to address these issues. OMAC provides access control for senders, receivers, and delivery nodes in overlay multicast. The proposed architecture, which is based on symmetric key cryptosystem, centralizes the authentication process in one server whereas it distributes the authorization process among the delivery nodes. Moreover, delivery nodes are utilized as a buffer zone between end systems and the authentication server, making it less exposed to malicious end systems. To evaluate our work, we have used simulation to compare the performance of OMAC against previous solutions. Results of the simulation show that OMAC outperforms previous multicast access control schemes. Copyright © 2010 John Wiley & Sons, Ltd.     

Communication-aware VFI partitioning for GALS-based networks-on-chip

The voltage/frequency island (VFI) design paradigm is a practical architecture for energy-efficient networks-on-chip (NoC) systems. In VFI-based NoC systems, each island can be operated with different voltage and clock frequency and thus it is important to carefully partition processing elements (PEs) into islands based on their workloads and communications. In this paper, we propose an energy-efficient design scheme that optimizes energy consumption and hardware costs in VFI-based NoC systems. Since on-chip networks take up a substantial portion of system power budget in NoC-based systems, the proposed scheme uses communication-aware VFI partitioning and tile mapping/routing algorithms to minimize the inter-VFI communications. Experimental results show that the proposed design technique can reduce communication energy consumption by 32–51% over existing techniques and total energy consumption by 3–14%.     

Multicast forwarding over ATM: Native approaches

Multicasting is growing in importance as new multimedia applications are devised. Throughout this article, multicasting is understood as the efficient multipoint-to-multipoint transmission of information (in terms of network resource consumption) between the members of a group. Most multicast services have been designed up to now to work over connectionless environments. The approach adopted by connection-oriented networks has been to try to imitate these connectionless multicast schemes with the aim of supporting IP multicast or network-layer broadcast. However, these solutions present drawbacks in terms of delay or signaling overhead. The goal of native ATM multicasting is to provide multicast communications support by taking into account the characteristics of ATM. Therefore, the design philosophy of multicast must be rethought by making it more suitable for connection-oriented networks. Native ATM multicasting is based on mechanisms implemented at the switches to allow the correct ATM-layer multicast forwarding of information. These mechanisms seek to avoid the delay and signaling problems of current solutions, e.g., LAN emulation and IP multicast over ATM. This article provides a survey of the literature on the strategies that offer multicast communications in ATM environments, with special stress on native ATM multicast forwarding mechanisms. Other aspects, such as signaling, quality of service, traffic control, and routing, are not addressed in detail in this article.     

基于LKH混合树的组播密钥更新方案

IP组播通信越来越得到广泛的应用，其密钥动态管理是一个值得关注的问题。本文主要对组播密钥更新方案进行分析，并对基于LKH密钥树的更新方案进行了改进。     

An analytical approach to the performance evaluation of the balanced gamma switch under multicast traffic

This paper presents the performance evaluation of a new cell‐based multicast switch for broadband communications. Using distributed control and a modular design, the balanced gamma (BG) switch features high performance for unicast, multicast and combined traffic under both random and bursty conditions. Although it has buffers on input and output ports, the multicast BG switch follows predominantly an output‐buffered architecture. The performance is evaluated under uniform and non‐uniform traffic conditions in terms of cell loss ratio and cell delay. An analytical model is presented to analyse the performance of the multicast BG switch under multicast random traffic and used to verify simulation results. The delay performance under multicast bursty traffic is compared with those from an ideal pure output‐buffered multicast switch to demonstrate how close its performance is to that of the ideal but impractical switch. Performance comparisons with other published switches are also studied through simulation for non‐uniform and bursty traffic. It is shown that the multicast BG switch achieves a performance close to that of the ideal switch while keeping hardware complexity reasonable. Copyright © 2006 John Wiley & Sons, Ltd.