CDMA核心网络构成

ＣＤＭＡ核心网络主要由以下几部分组 成： ＨＬＲ／ＡＣ／ＳＣＰ：合一设置的归属位置寄存器／鉴权中心／业务控制点 ＭＳＣ／ＳＳＰ：合一设置的移动交换中心／业务交换点 ＭＣ／ＶＭＳ：合一设置的短消息中心／语音信箱 ＶＬＲ：拜访位置寄存器 ＢＳＳ：基站子系统 ＳＣＰ：独立的业务控制点 ＯＭＣ：操作维护中心 ＩＷＦ：网络互联单元 ＳＴＰ;信令转接点 ＣＤＭＡ网络遵循的空中接口标准协议是ＩＳ－９５,该标准可以分为两个阶段即ＩＳ－９５Ａ和ＩＳ－９６Ｂ,ＩＳ－９５Ａ支持的最高速率为９.６ｋｂｐｓ,ＩＳ－９６Ｂ支持的最高速…     

微机总线及接口技术的发展

１总线结构的类型 ＰＣ机的系统总线可分 为 ＩＳＡ、ＥＩＳＡ、ＭＣＡ、ＶＥＳＡ、ＰＣＩ、ＡＧＰ等多种标准。 （ １）ＩＳＡ／ＥＩＳＡ／ＭＣＡ／ＶＥＳＡ总线 ＩＳＡ（Ｉｎｄｕｓｔｒｙ Ｓｔａｎｄａｒｄ　Ａｒｃｈｉｔｅｃｔｕｒｅ）,是ＩＢＭ公司为２８６／ＡＴ电脑制定的总线工业标准,也称为ＡＴ标准。ＩＳＡ总线的影响力非常大,直到现在仍存在大量ＩＳＡ设备。 ＥＩＳＡ（Ｅｘｔｅｎｄｅｄ　Ｉｎｄｕｓｔｒｙ　 Ａｒｃｈｉｔｅｃｔｕｒｅ）,是 ＥＩＳＡ集团（由 Ｃｏｍｐａｑ、ＨＰ、ＡＳＴ等组成）专为３２位ＣＰＵ设计的总线…     

FIELDBUS与NOVELL网互联技术的研究

本文通过对ＦＩＥＬＤＢＵＳ及ＮＯＶＥＬＬ网体系结构的分析，研究了ＦＩＥＬＤＢＵＳ与ＮＯＶＥＬＬ网互联的可能性及互联方法，并对其中的两种方法（基于ＴＣＰ／ＩＰ协议的互联方法和基于应用层的互联方法）的实现技术作了深入的探讨，并在实验室里实现了二者的互联。     

信息港

天域空间 仅售２８０元的ＰＲＯＭＩＳＥ ＵＤＭＡ／６６卡 最近,美国Ｐｒｏｍｉｓｅ公司推出了几款不同档次的ＵＤＭＡ／６６ＲＡＩＤ产品。随着硬盘外部传输率的不断提高, ＵＤＭＡ／６６已成为新一代的外部传输标准。 ＰＲＯＭＩＳＥ ＵＤＭＡ／６６卡采用ＰＲＯＭＩＳＥ公司的ＰＤＣ２０２６２的主控芯片,自带有可编程的ＢＩＯＳ。可以提供两个支持Ｕｌｔｒａ ＤＭＡ／６６协议的ＩＤＥ端口。可以连接４个ＩＤＥ设备。并且支持各种ＩＤＥ标准,（ＩＤＥ,ＥＩＤＥ,Ｆａｓｔ－ＡＴＡ, Ｕｌｔｒａ－ＡＴＡ）。 ＰＲＯＭＩＳＥ ＵＤＭ…     

用增强并口EPP协议扩展计算机的ISA接口

提出了用ＥＰＰ协议和ＣＰＬＤ扩展笔记本电脑的ＩＳＡ接口的方法,给出了详细的技术解决方案。扩展的ＩＳＡ接口可以达到１３１０ｋＢ／ｓ的双向通讯速度,与ＩＳＡ本身的速度相当。用户可以通过扩展的ＩＳＡ接口直接使用市场上的基于ＩＳＡ的接口卡。     

用增强并口EPP协议扩展计算机的ISA接口

提出了用ＥＰＰ协议和ＣＰＬＤ扩展笔记本电脑的ＩＳＡ接口的方法,给出了详细的技术解决方案。扩展的ＩＳＡ接口可以达到１３１０ ＫＢ／ｓ的双向通讯速度,与ＩＳＡ本身的速度相当。用户可以通过扩展的ＩＳＡ接口直接使用市场上的基于ＩＳＡ的接口卡。     

分析与评测

“测试是检验真正六类的标准”自从 １９９７年９月国际 ＩＳＯ／ＩＥＣ布线标准组织召开未来六类／Ｅ级新闻发布会以来,随着其六类／Ｅ级标准的逐渐成熟,六类系统成为未来布线发展的大趋势。但与此同时,真假六类充斥市场,使用户无法辨别。为了建立公平的竞争环境,保护广大用户的利益,本文提醒业界和用户：“现场三节点链路测试是检验六类的基本标准”。 国际标准对六类测试是怎样规定的？ 目前积极研究和制定六类／Ｅ级草案性能指标的两大组织是ＩＳＯ／ＩＥＣ ＪＴＣ１／ＳＣ ２５／ＷＧ３和 ＡＮＳＩ／ＴＬＡ／ＥＩＡ ＴＢ４２． …     

基于嵌入式主板的CM-STB系统设计

本文介绍的 Ｃ Ｍ － Ｓ Ｔ Ｂ类似于 Ｗ Ｅ Ｂ－ Ｔ Ｖ,它以普通电视机或监视器为输出设备,作为 Ｖ Ｏ Ｄ系统的一部分,通过网络互联实现 Ｉｎｔｅｒｎｅｔ Ｗ Ｗ Ｗ 浏览、收发 Ｅ Ｍ Ａ Ｉ Ｌ和点播节目等功能。文中着重介绍的是 Ｃ Ｍ－ Ｓ Ｔ Ｂ的硬件系统结构。     

自已动手架设UBB讨论区

安装ＡＣＴＩＶＥ ＰＥＲＬ ｌ由于 ＵＬＴＩＭＡＴＥ ＢＨＬＬＥＴＩＮＢＯＡＲＤ ＭＭ．Ｍ＊ｕ ＣＧＩ撰写的讨论区程序,因此如果要在ＷＩＮＤＯＷＳ环境下执行,就必须安装ＰＥＲＬ执行程序。所以首先请到这里下载免费的ＡＣＴＩＶＥＰＥＲＬ程序：ＨＴＴＰ：／／ＷＷＷ．ＡＣＴＩＶＥＳＴＡＴＥ．ＣＯＭ／ＤＯＷＮ－ＬＯＡＤ／ＡＣＴＩＶＥＰＥＲＬ／ＷＩＮＤＯＷＳ／５．６／ＡＣＴＩＶＥＰＥＲＬ－５．６．０．６２３－ＭＳＷＩＮ３２－Ｘ８６－ＭＵＬＴＩ—ＴＨＲＥＡＤ．ＭＳＩ。 下载完后,请直接执行ＡＣＴＩＶＥＰＥＲＬ－５．…     

CIMS环境下C/S与B/S混合模式CAPP系统的研究与开发

在基于ＣＩＭＳ环境下,ＣＡＰＰ不仅需要与ＣＡＤ／ＣＡＭ的集成,而且也必须与ＥＲＰ／ＭＨＰＩＩ／ＭＩＳ等分系统集成的思想,该文分析了ＣＡＰＰ与ＣＡＤ／ＣＡＭ、ＥＲＰ／ＭＲＰＩＩ／ＭＩ　、ＣＡＱ、ＦＭＳ／ＦＭＣ等分系统之间的关系和数据流,指出ＣＩＭＳ环境下不同用户对象对ＣＡＰＰ的要求及用户权限的差异。并据此提出基于Ｃ／Ｓ与Ｂ／Ｓ混合模式的ＣＡＰＰ系统设计方法。结合具体 ＣＩＭＳ环境,开发了以 Ｗｅｂ和数据库为支持环境的混合模式集成化 ＣＡＰＰ系统。     

SCI互连技术研究

采用一种适当的系统互连技术构建一个高带宽、低延迟、可伸缩的互连系统是当前并行，分布式处理的趋势。可伸缩一致性接口（SCI）是一种高性价比的系统互连解决方案。该文对SCI作了一些简单介绍，然后提出了一种嵌入式SCI互连系统。     

The Stanford Dash multiprocessor

The overall goals and major features of the directory architecture for shared memory (Dash) are presented. The fundamental premise behind the architecture is that it is possible to build a scalable high-performance machine with a single address space and coherent caches. The Dash architecture is scalable in that it achieves linear or near-linear performance growth as the number of processors increases from a few to a few thousand. This performance results from distributing the memory among processing nodes and using a network with scalable bandwidth to connect the nodes. The architecture allows shared data to be cached, significantly reducing the latency of memory accesses and yielding higher processor utilization and higher overall performance. A distributed directory-based protocol that provides cache coherence without compromising scalability is discussed in detail. The Dash prototype machine and the corresponding software support are described     

SCIPVM: Parallel distributed computing on SCI workstation clusters

Workstation and PC clusters interconnected by SCI (scalable coherent interface) are very promising technologies for high-performance cluster computing. Using commercial SBus to SCI interface cards and system software and drivers, a two-workstation cluster has been constructed for initial testing and evaluation. The PVM system has been adapted to operate on this cluster using both raw channel and shared-memory access to the SCI interconnect, and preliminary communications performance tests have been carried out. To achieve mutual exclusion in accessing shared-memory segments, two protocols were used. Our preliminary results indicate that communications throughput in the range of 17.7 Mbytes/s, and round-trip latencies of 80 μs using the first and 140 μs using the second protocol, can be obtained on SCI clusters. These figures are significantly better (by a factor of 2 to 4) for small and large messages than those attainable on Fast Ethernet LANs. Since these performance results are very encouraging, we expect that, in the very near future, SCI networks will be capable of delivering several tens of Mbytes/s bandwidth and a few tens of microseconds latencies, and will significantly enhance the viability of cluster computing. Copyright © 1999 John Wiley & Sons, Ltd.     

An optical interconnection network and a modified snooping protocol for the design of large-scale symmetric multiprocessors (SMPs)

In symmetric multiprocessors (SMPs), the cache coherence overhead and the speed of the shared buses limit the address/snoop bandwidth needed to broadcast transactions to all processors. As a solution, a scalable address subnetwork called symmetric multiprocessor network (SYMNET) is proposed in which address requests and snoop responses of SMPs are implemented optically. SYMNET not only uses passive optical interconnects that increases the speed of the proposed network, but also pipelines address requests at a much faster rate than electronics. This increases the address bandwidth for snooping, but the preservation of cache coherence can no longer be maintained with the usual snooping protocols. A modified coherence protocol, coherence in SYMNET (COSYM), is introduced to solve the coherence problem. COSYM was evaluated with a subset of Splash-2 benchmarks and compared with the electrical bus-based MOESI protocol. The simulation studies have shown a 5-66 percent improvement in execution time for COSYM as compared to MOESI for various applications. Simulations have also shown that the average latency for a transaction to complete using COSYM protocol was 5-78 percent better than the MOESI protocol. It is also seen that SYMNET can scale up to hundreds of processors while still using fast snooping-based cache coherence protocols, and additional performance gains may be attained with further improvement in optical device technology.     

Analysis of Mean Transfer Delay on SCI Ring

The scalable coherent interface (SCI) is an IEEE standard whose basic topology is ringlet, a kind of buffer insertion ring. SCI ring allows more than one message transfer concurrently, which brings difficulty on modeling SCI ring analytically.This paper presents an analytic expression on mean transfer delay using M/G/1 queuing model with non-preemptive priority. A preliminary performance study is also presented.     

SCI中资源调度算法的分析与仿真

IEEE的1596协议标准SCI是一个面向高速、低延迟应用的互联协议。主要应用在大规模的集群系统以及实时性要求较高的任务系统。为了保证在数据通信中的高速、低延迟,SCI在每个节点输出、输入接口处分别提供了两个重要的资源调度算法——带宽分配协议及队列分配协议。文中将对这两种调度算法进行深入的分析及仿真,并对结果进行分析,提出了下一步的研究方向。     

SCI数据通信技术的研究和实现

随着计算机应用领域的拓展与加深,对计算机性能的要求也越来越高,进而对系统中的信息交互提出了更高的要求。传统的总线技术由于存在固有的限制,已经成为阻碍系统性能提高的瓶颈。SCI的出现克服了总线技术的不足,大大改善了信息交互的效率和带宽,满足了系统中和系统间的互连要求,成为先进互连技术的代表。详细分析了在WindowsXP环境下,开发SCI数据通信程序的原理和方法。     

SCI数据通信技术的研究和实现

随着计算机应用领域的拓展与加深，对计算机性能的要求也越来越高，进而对系统中的信息交互提出了更高的要求。传统的总线技术由于存在固有的限制，已经成为阻碍系统性能提高的瓶颈。SCI的出现克服了总线技术的不足，大大改善了信息交互的效率和带宽，满足了系统中和系统间的互连要求，成为先进互连技术的代表。详细分析了在Windows XP环境下，开发SCI数据通信程序的原理和方法。     

Integrated Memory Controllers with Parallel Coherence Streams

Previous work in scalable hardware distributed shared memory (DSM) multiprocessors has established the critical and dominant role that protocol processing bandwidth (or its inverse, occupancy) plays in determining overall performance in architectures with standalone memory/coherence controllers. However, with recent architectural trends toward integrated (on-chip) memory controllers and the well-known fact that processor frequency is increasing more rapidly than memory systems, we must ask whether parallel coherence processing engines (either multiple integrated protocol processors/cores or multiple protocol threads) are needed in DSM machines constructed from modern processor architectures and, if so, when. We construct a useful analytical model to give the designer insight into when parallel coherence streams will improve performance and verify our model via detailed simulation on 64-threaded microbenchmarks and parallel applications and on single-node multiprogrammed workloads. Surprisingly, and contrary to related work, we find that, in these architectures, adding a second coherence engine has almost no impact on performance. Further, for less-tuned applications that suffer from hot spots (contentious requests to the same memory line), additional engines offer no benefit whatsoever. Even with double the memory bandwidth (or channels), an additional coherence processing stream yields only slight performance improvement. Only for a special class of DSM machines employing directoryless broadcast protocols over unordered interconnects does parallel "snoop" processing offer reasonable performance improvement for communication-intensive applications. Overall, given the architectural trends, this is good news for DSM designers who want to minimize the resources necessary (protocol threads or integrated protocol processor cores for maintaining internode coherence, respectively) to create SMTp-based or multi-CMP-based scalable DSM machines using directory protocols.     

A comparative performance analysis of reliable group rekey transport protocols for secure multicast

In this paper, we present a new scalable and reliable key distribution protocol for group key management schemes that use logical key hierarchies (LKH) for scalable group rekeying. Our protocol called WKA-BKR is based upon two ideas—weighted key assignment and batched key retransmission—both of which exploit the special properties of LKH and the group rekey transport payload to reduce the bandwidth overhead of the reliable key delivery protocol. Using both analytic modeling and simulation, we compare the performance of WKA-BKR with that of other rekey transport protocols, including a recently proposed protocol based on proactive FEC. Our results show that for most network loss scenarios, the bandwidth used by WKA-BKR is lower than that of the other protocols.