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<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/626d840240256a40ce5ebd17/bg1.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">《电子商务与实践<span class="_ _0"></span>》——中国科学技<span class="_ _0"></span>术大学商学院——<span class="_ _0"></span>（ <span class="_ _1"> </span>2004.<span class="_ _0"></span>9<span class="ff2">~</span>200<span class="_ _0"></span>5.1<span class="_ _1"> </span>）</div></div><div class="c x0 y3 w3 h4"><div class="t m0 x2 h5 y4 ff1 fs1 fc1 sc0 ls0 ws0">第二讲 电子商务的基础设施</div><div class="t m0 x3 h6 y5 ff1 fs2 fc0 sc0 ls0 ws0">主讲人：苟清龙</div><div class="t m0 x3 h6 y6 ff1 fs2 fc0 sc0 ls0 ws0">单 位：中国科学技术大学</div><div class="t m0 x3 h6 y7 ff1 fs2 fc0 sc0 ls0 ws0">信息管理与决策科学系</div><div class="t m0 x3 h7 y8 ff2 fs2 fc0 sc0 ls0 ws0">Email: <span class="fc2">tslg@ustc.edu.cn</span></div></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
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<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/626d840240256a40ce5ebd17/bg2.jpg"><div class="c x0 y3 w3 h4"><div class="t m0 x4 h8 y9 ff2 fs3 fc0 sc0 ls0 ws0">22/5/1<span class="_ _2"> </span> <span class="_ _3"> </span>2</div><div class="t m0 x5 h5 ya ff1 fs1 fc1 sc0 ls0 ws0">电子商务的基础设施</div><div class="t m0 x6 h9 yb ff3 fs4 fc3 sc0 ls0 ws0"></div><div class="t m0 x7 ha yc ff1 fs5 fc0 sc0 ls0 ws0">数据路由选择和基础<span class="_ _0"></span>协议</div><div class="t m0 x6 h9 yd ff3 fs4 fc3 sc0 ls0 ws0"></div><div class="t m0 x7 ha ye ff1 fs5 fc0 sc0 ls0 ws0">互联网的应用</div><div class="t m0 x6 h9 yf ff3 fs4 fc3 sc0 ls0 ws0"></div><div class="t m0 x7 ha y10 ff1 fs5 fc0 sc0 ls0 ws0">标注语言</div><div class="t m0 x6 h9 y11 ff3 fs4 fc3 sc0 ls0 ws0"></div><div class="t m0 x7 ha y12 ff2 fs5 fc0 sc0 ls0 ws0">WWW<span class="_ _4"> </span><span class="ff1">技术</span></div><div class="t m0 x6 h9 y13 ff3 fs4 fc3 sc0 ls0 ws0"></div><div class="t m0 x7 ha y14 ff1 fs5 fc0 sc0 ls0 ws0">互联网、内部网和外<span class="_ _0"></span>部网</div><div class="t m0 x6 h9 y15 ff3 fs4 fc3 sc0 ls0 ws0"></div><div class="t m0 x7 ha y16 ff1 fs5 fc0 sc0 ls0 ws0">互联网接入的各种方<span class="_ _0"></span>案及其优缺点</div></div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/626d840240256a40ce5ebd17/bg3.jpg"><div class="c x0 y3 w3 h4"><div class="t m0 x4 h8 y9 ff2 fs3 fc0 sc0 ls0 ws0">22/5/1<span class="_ _2"> </span> <span class="_ _3"> </span>3</div><div class="t m0 x5 hb y17 ff1 fs6 fc1 sc0 ls0 ws0">第一节 数据路由<span class="_ _5"></span>选择和基础协议</div><div class="t m0 x6 h9 yb ff3 fs4 fc3 sc0 ls0 ws0"></div><div class="t m0 x8 ha yc ff1 fs5 fc0 sc0 ls0 ws0">包交换网</div><div class="t m0 x9 hc y18 ff3 fs7 fc2 sc0 ls0 ws0"></div><div class="t m0 xa hd y19 ff1 fs8 fc0 sc0 ls0 ws0">线路交换不适<span class="_ _5"></span>合计算机通信</div><div class="t m0 xb he y1a ff3 fs9 fc3 sc0 ls0 ws0"></div><div class="t m0 xc h6 y1b ff1 fs2 fc0 sc0 ls0 ws0">什么是线路交换</div><div class="t m0 xc hf y1c ff3 fsa fc4 sc0 ls0 ws0"></div><div class="t m0 xd h3 y1d ff1 fs0 fc0 sc0 ls0 ws0">电话公司的交换设备<span class="_ _0"></span>（既可能是机械的也可能<span class="_ _0"></span>是计</div><div class="t m0 xd h3 y1e ff1 fs0 fc0 sc0 ls0 ws0">算机化的）选择特定<span class="_ _0"></span>的电话线，或称为线路，<span class="_ _0"></span>并把</div><div class="t m0 xd h3 y1f ff1 fs0 fc0 sc0 ls0 ws0">线路连接起来在打电<span class="_ _0"></span>话和接电话的人之间形成<span class="_ _0"></span>一条</div><div class="t m0 xd h3 y20 ff1 fs0 fc0 sc0 ls0 ws0">通路。这种中央控制<span class="_ _0"></span>的单线连接模式叫做线路<span class="_ _0"></span>交换。</div><div class="t m0 xb he y21 ff3 fs9 fc3 sc0 ls0 ws0"></div><div class="t m0 xc h6 y22 ff1 fs2 fc0 sc0 ls0 ws0">线路交换不适合计算机通信</div></div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
<div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/626d840240256a40ce5ebd17/bg4.jpg"><div class="c x0 y3 w3 h4"><div class="t m0 x4 h8 y9 ff2 fs3 fc0 sc0 ls0 ws0"><span class="fc5 sc0">22/</span><span class="fc5 sc0">5/</span><span class="fc5 sc0">1</span><span class="_ _2"> </span><span class="fc5 sc0"> </span><span class="_ _3"> </span><span class="fc5 sc0">4</span></div><div class="t m0 xe h10 y23 ff3 fsb fc2 sc0 ls0 ws0"></div><div class="t m0 xf h6 y24 ff1 fs2 fc0 sc0 ls0 ws0">包交换网的工作原理</div></div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
<div id="pf5" class="pf w0 h0" data-page-no="5"><div class="pc pc5 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/626d840240256a40ce5ebd17/bg5.jpg"><div class="c x0 y3 w3 h4"><div class="t m0 x4 h8 y9 ff2 fs3 fc0 sc0 ls0 ws0">22/5/1<span class="_ _2"> </span> <span class="_ _3"> </span>5</div><div class="t m0 xb h6 y25 ff1 fs9 fc0 sc0 ls0 ws0">①<span class="_ _6"> </span><span class="fs2">在包交换网络中，文件和信息被分解成包，在</span></div><div class="t m0 xc h6 y26 ff1 fs2 fc0 sc0 ls0 ws0">这些包上用表示信息源和目的地的代码打上电</div><div class="t m0 xc h6 y27 ff1 fs2 fc0 sc0 ls0 ws0">子标签。这些包在网络中从一台计算机传输到</div><div class="t m0 xc h6 y28 ff1 fs2 fc0 sc0 ls0 ws0">另一台计算机，直至到达目的地。目的地的计</div><div class="t m0 xc h6 y29 ff1 fs2 fc0 sc0 ls0 ws0">算机把这些包集中起来，并把每包中的信息重</div><div class="t m0 xc h6 y2a ff1 fs2 fc0 sc0 ls0 ws0">新集合成原先的数据。</div><div class="t m0 xb h6 y2b ff1 fs9 fc0 sc0 ls0 ws0">②<span class="_ _6"> </span><span class="fs2">在包交换中，每个包从源到目的地的最佳路径</span></div><div class="t m0 xc h6 y2c ff1 fs2 fc0 sc0 ls0 ws0">是由途经的各个计算机决定的。决定包的传送</div><div class="t m0 xc h6 y2d ff1 fs2 fc0 sc0 ls0 ws0">路径的计算机通常叫做路由器，确定最佳路径</div><div class="t m0 xc h6 y2e ff1 fs2 fc0 sc0 ls0 ws0">的程序叫做路由算法。</div></div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
