【正文】 小型網(wǎng)絡(luò)（網(wǎng)絡(luò)少于有 250 臺主機(jī)） 。其中有一部分地址用于識別網(wǎng)絡(luò)系統(tǒng)連接的，而其余的是用來識別系統(tǒng)本身的。通常情況下，這個(gè)地址通過點(diǎn)分為四個(gè) 8 位的數(shù)字。互聯(lián)網(wǎng)協(xié)議規(guī)定，如果在相同的物理網(wǎng)絡(luò)中，在任何網(wǎng)絡(luò)上的任何系統(tǒng)都能夠很 輕易的實(shí)現(xiàn)通信。 按照慣例， TCP/IP 是一整套協(xié)議，都是基于互聯(lián)網(wǎng)協(xié)議 （ IP 協(xié)議）?？傊粋€(gè)協(xié)議定義了 “ 信息通信的規(guī)則 ” ，網(wǎng)絡(luò)中的每臺 計(jì)算機(jī)必須遵循以便使所有的系統(tǒng)可以進(jìn)行數(shù)據(jù)交換。當(dāng)然，物理硬件必須存在， 像 典型的網(wǎng)絡(luò)接 口卡（網(wǎng)卡）或一個(gè)撥號網(wǎng)絡(luò)連接的串行通信端口。在開始利用該控件編程之前，我們先來學(xué)習(xí)一下 通常sockets 編程中 基本術(shù)語和概念。在工程部 件里包含了這個(gè)控件，設(shè)置它的屬性和響應(yīng)它的事件你可以更加迅速而 容易的實(shí)現(xiàn)網(wǎng)絡(luò)程序的應(yīng)用。另外一種方式是通過設(shè)置屬性和響應(yīng)事件來使用所提供的更高層次的接口的組件。假定讀者已經(jīng)熟悉可視化程序設(shè)計(jì)而且已經(jīng)安裝了SocketWrench 控件， 如果你對 socket 編程已經(jīng)有所了解 ，那你可以跳過這一節(jié) 的內(nèi)容? 當(dāng)在利用 Windows Sockets 創(chuàng)建一個(gè)程序時(shí)，有兩個(gè)基本途徑。 SocketTools 容納了一些備受歡迎的互聯(lián)網(wǎng) 應(yīng)用協(xié)議的組件及類庫，如ftp ， pop3 ， smtp 和 。在 Windows Sockets 編程之后，本文將介紹基本概念并且使用 SocketWrench 來實(shí)現(xiàn)你的第一個(gè)應(yīng)用程序。t have this overhead, and is considerably faster than TCP. In those situations where speed is paramount, or the number of packets sent over the work must be kept to a minimum, UDP is the solution. 譯文如下： TCP/IP 入門介紹 作者 Catalyst Development Catalyst Development 是全球公認(rèn)的領(lǐng)先的互聯(lián)網(wǎng)軟件之一，其屢獲殊榮的產(chǎn)品已廣泛為世界各地成千上萬的企業(yè)、政 府和獨(dú)立開發(fā)商所使用 。s used at all. UDP has the advantage over TCP in two critical areas: speed and packet overhead. Because TCP is a reliable protocol, it goes through great lengths to insure that data arrives at it39。s responsibility is to wait, listen and respond to ining connections. Once the connection has been established, both sides may send and receive data until the connection is closed. User Datagram Protocol Unlike TCP, the User Datagram Protocol (UDP) does not present data as a stream of bytes, nor does it require that you establish a connection with another program in order to exchange information. Data is exchanged in discrete units called datagrams, which are similar to IP datagrams. In fact, the only features that UDP offers over raw IP datagrams are port numbers and an optional checksum. UDP is sometimes referred to as an unreliable protocol because when a program sends a UDP datagram over the work, there is no way for it to know that it actually arrived at it39。t need to write code to handle dropped or outoforder datagrams, and instead can focus on the application itself. And because the data is presented as a stream of bytes, existing code can be easily adopted and modified to use TCP. TCP is known as a connectionoriented protocol. In other words, before two programs can begin to exchange data they must establish a connection with each other. This is done with a threeway handshake in which both sides exchange packets and establish the initial packet sequence numbers (the sequence number is important because, as mentioned above, datagrams can arrive out of order。s destination. In fact, datagrams may be lost, duplicated or delivered out of order during their travels over the work. Needless to say, this kind of unreliability can cause a lot of problems for software developers. What39。ll cover the basic terminology and concepts behind sockets programming in general. Transmission Control Protocol (TCP) When two puters wish to exchange information over a work, there are several ponents that must be in place before the data can actually be sent and received. Of course, the physical hardware must exist, which is typically either a work interface card (NIC) or a serial munications port for dialup working connections. Beyond this physical connection, however, puters also need to use a protocol which defines the parameters of the munication between them. In short, a protocol defines the rules of the road that each puter must follow so that all of the systems in the work can exchange data. One of the most popular protocols in use today is TCP/IP, which stands for Transmission Control Protocol/Inter Protocol. By convention, TCP/IP is used to refer to a suite of protocols, all based on the Inter Protocol (IP). Unlike a single local work, where every system is directly connected to each other, an inter is a collection of works, bined into a single, virtual work. The Inter Protocol provides the means by which any system on any work can municate with another as easily as if they were on the same physical work. Each system, monly referred to as a host, is assigned a unique 32bit number which can be used to identify it over the work. Typically, this address is broken into four 8bit numb