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传统的以太网是一个广播型网络，网络中的所有主机通过HUB 或交换机相连，处在 同一个广播域中。HUB 是物理层设备，没有交换功能，接收的报文会向所有端口转 发；交换机是链路层设备，具备根据报文的目的MAC 地址进行转发的能力，但在 收到广播报文或未知单播报文（报文的目的MAC 地址不在交换机MAC 地址表中） 时，也会向除交换机报文入端口之外的所有端口转发。 上述情况使网络中的主机会收到大量并非以自身为目的地的报文，在浪费大量带宽 资源的同时，也造成了严重的安全隐患。 隔离广播域的传统方法是使用路由器，但是路由器成本较高，而且端口较少，无法 划分细致的网络。 为解决以太网交换机在LAN 中无法限制广播的问题，出现了VLAN（Virtual Local Area Network，虚拟局域网）技术。-err

ARM JTAG调试原理,讲述了ARM的JTAG调试的原理及方法-The principle and method of debugging ARM via JTAG

操作系统概论英文电子版 .doc格式 有21章 高等教育出版社-electronic version. Doc format Chapter 21 Higher Education Pre

Data Structures & Algorithms in Java by Robert Lafore ISBN: 1571690956 Sams © 1998, 617 pages Beautifully written and illustrated, this book introduces you to manipulating data in practical ways using Java examples

Writing Robust Java Code The AmbySoft Inc. Coding Standards for Java v17.01d Scott W. Ambler Software Process Mentor This Version: January 15, 2000 Copyright 1998-1999 AmbySoft Inc.Purpose of this White Paper This white paper describes a collection of standards, conventio code. They are based on sound, proven software engineering p understand, to maintain, and to enhance. Furthermore, by foll productivity as a Java developer should increase remarkably ¨C write high-quality code right from the start you will have a much development process. Finally, following a common set of codi making teams of developers significantly more productive.-Writing Robust Java CodeThe AmbySoft Inc. Coding Standards for Javav17.01dScott W. AmblerSoftware Process MentorThis Version: January 15, 2000Copyright 1998-1999 AmbySoft Inc.Purpose of this White PaperThis white paper describes a collection of standards, conventiocode. They are based on sound , proven software engineering p

非接触IC卡读写程序编制-non-contact IC card reader programming

c++primer第三版中文版（PDF）-c++ primer third edition of the Chinese version (PDF)

fundamentals of wimax technology.

本篇文章叙述了锁相环原理，是学习锁相技术不可多得一篇好文章-This article describes the principle of phase-locked loop, phase-locking technology is invaluable to learn a good article

VC绘图程序教程 -VC mapping procedures Tutorial