數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)--網(wǎng)絡(luò)互連與internet技術(shù)（2）-預(yù)覽頁
【正文】 部門以及高新企業(yè)的研發(fā)提供服務(wù) ? 中國公用計算機(jī)互聯(lián)網(wǎng)（ CHINANET） ? 由郵電部 1994年投資建設(shè)，主要用于商業(yè)用途 ? 中國教育與科研網(wǎng)（ CERNET） ? 國家計委投資、教育部主持于 1994年建設(shè)，主要目標(biāo)是將全國的高校連接起來，為教育和科研服務(wù) ? 中國金橋信息網(wǎng)（ CGBNET） ? 又叫國家公用經(jīng)濟(jì)信息通信網(wǎng)，由吉通公司主持建設(shè) ? 其他互聯(lián)網(wǎng)。采用 TCP/IP協(xié)議 ? 入網(wǎng)方式靈活多樣。 帶寬需求呈超高速增長的趨勢 邁特卡爾夫定律 :聯(lián)網(wǎng)定律 ， 網(wǎng)絡(luò)價值隨用戶數(shù)平方成正比。第三章 網(wǎng)絡(luò)互連與 Inter技術(shù) Inter技術(shù) Inter 的形成和發(fā)展 ? Inter的形成 ? 形成階段： ? 1969年分組交換網(wǎng) ARPA建成。 所有電子系統(tǒng)（包括電子通信系統(tǒng)，計算機(jī)）都適用 光纖定律 ： 超摩爾定律 ，骨干網(wǎng)帶寬 9個月 翻番， 10年10000倍 。所有的子網(wǎng)的地位是平等的 ? 具有開放行。 ? 資源分散。 most of the block is wasted TCP/IP協(xié)議 特殊的 IP地址 Special Address Netid Hostid Source or Destination Network address Specific All 0s None Direct broadcast address Specific All 1s Destination Limited broadcast address All 1s All 1s Destination This host on this work All 0s All 0s Source Specific host on this work All 0s Specific Destination Loopback address 127 Any Destination TCP/IP協(xié)議 Network address TCP/IP協(xié)議 Direct broadcast address TCP/IP協(xié)議 Limited broadcast address TCP/IP協(xié)議 This host on this work TCP/IP協(xié)議 Specific host on this work TCP/IP協(xié)議 Loopback address Private Addresses A number of blocks in each class are assigned for private use. They are not recognized globally. TCP/IP協(xié)議 TCP/IP協(xié)議 Class Netid Total A 1 B To 16 C TO 256 Private Addresses TCP/IP協(xié)議 多地址的主機(jī) A mask is a 32bit binary number that gives the first address in the block (the work address) when bitwise ANDed with an address in the block. TCP/IP協(xié)議 子網(wǎng)掩碼 TCP/IP協(xié)議 工作原理 TCP/IP協(xié)議 The work address is the beginning address of each block. It can be found by applying the default mask to any of the addresses in the block (including itself). It retains the id of the block and sets the hostid to zero TCP/IP協(xié)議 掩碼的作用 Given the address and the class C default mask, find the beginning address (work address). The default mask is , which means that the first 2 bytes are preserved and the other 2 bytes are set to 0s. The work address is . TCP/IP協(xié)議 例如： 謝謝觀看 /歡迎下載 BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES. BY FAITH I BY FAITH
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