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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/627ef4dcebb030486d10030d/bg1.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0"> <span class="ff2 sc1">网络课程设计报告</span></div><div class="t m0 x2 h4 y3 ff2 fs1 fc0 sc1 ls0 ws0">题目:<span class="ff1 sc0">UDP<span class="_ _0"> </span></span>服务器与客户端设计</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></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/627ef4dcebb030486d10030d/bg2.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x3 h5 y4 ff2 fs2 fc0 sc0 ls0 ws0">目录</div><div class="t m0 x4 h6 y5 ff2 fs3 fc0 sc0 ls0 ws0">一、 需求分析<span class="ff3">......<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>......<span class="_ _2"></span>....<span class="_ _2"></span>..<span class="_ _1"></span>3</span></div><div class="t m0 x5 h6 y6 ff2 fs3 fc0 sc0 ls0 ws0">(<span class="ff3">1</span>) 设计的目的与意义<span class="ff3">........<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>.........3</span></div><div class="t m0 x5 h6 y7 ff2 fs3 fc0 sc0 ls0 ws0">(<span class="ff3">2</span>) <span class="ff3">UDP<span class="_ _3"> </span></span>简介<span class="ff3">........<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>...................<span class="_ _2"></span>.....<span class="_ _2"></span>.<span class="_ _1"></span>3</span></div><div class="t m0 x5 h6 y8 ff2 fs3 fc0 sc0 ls0 ws0">(<span class="ff3">3</span>) 系统设计总体要求<span class="ff3">........<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>.........4</span></div><div class="t m0 x4 h6 y9 ff2 fs3 fc0 sc0 ls0 ws0">二、 总体设计<span class="ff3">......<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>......<span class="_ _2"></span>....<span class="_ _2"></span>..<span class="_ _1"></span>4</span></div><div class="t m0 x5 h6 ya ff2 fs3 fc0 sc0 ls0 ws0">(<span class="ff3">1</span>) 总体设计思想<span class="ff3">........<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>.................4</span></div><div class="t m0 x5 h6 yb ff2 fs3 fc0 sc0 ls0 ws0">(<span class="ff3">2</span>) 服务器与客户端工作流程<span class="ff3">........<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>..........<span class="_ _1"></span>5</span></div><div class="t m0 x4 h6 yc ff2 fs3 fc0 sc0 ls0 ws0">三、 详细设计与编码<span class="ff3">......<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>...........<span class="_ _2"></span>..5</span></div><div class="t m0 x5 h6 yd ff2 fs3 fc0 sc0 ls0 ws0">(<span class="ff3">1</span>) 相关函数说明<span class="ff3">........<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>.................5</span></div><div class="t m0 x5 h6 ye ff2 fs3 fc0 sc0 ls0 ws0">(<span class="ff3">2</span>) 相关函数分析<span class="ff3">........<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>.................6</span></div><div class="t m0 x5 h6 yf ff2 fs3 fc0 sc0 ls0 ws0">(<span class="ff3">3</span>) 代码实现<span class="ff3">........<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>..........<span class="_ _2"></span>...8</span></div><div class="t m0 x4 h6 y10 ff2 fs3 fc0 sc0 ls0 ws0">四、 测试的步骤和内容<span class="ff3">......<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.......<span class="_ _2"></span>..9</span></div><div class="t m0 x4 h6 y11 ff2 fs3 fc0 sc0 ls0 ws0">五、 心得体会<span class="ff3">......<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>...............<span class="_ _2"></span>.....<span class="_ _2"></span>...1<span class="_ _4"></span>1</span></div><div class="t m0 x4 h6 y12 ff2 fs3 fc0 sc0 ls0 ws0">六、 参考文献<span class="ff3">......<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>.............<span class="_ _1"></span>............<span class="_ _1"></span>.............<span class="_ _1"></span>...............<span class="_ _2"></span>.....<span class="_ _2"></span>...1<span class="_ _4"></span>1</span></div></div><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' onclick='return false;'><div class="d m1"></div></a><a class="l" rel='nofollow' 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<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/627ef4dcebb030486d10030d/bg3.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x4 h7 y13 ff2 fs4 fc0 sc1 ls0 ws0">一、<span class="_ _5"> </span>需求分析</div><div class="t m0 x4 h5 y14 ff2 fs2 fc0 sc1 ls0 ws0">(<span class="ff4 sc0">1</span>)<span class="_ _6"> </span>设计的目的与意义</div><div class="t m0 x6 h5 y15 ff2 fs2 fc0 sc0 ls0 ws0">随着<span class="_ _2"></span>经济<span class="_ _2"></span>的发展<span class="_ _7"></span><span class="ff5">,</span>社<span class="_ _2"></span>会的<span class="_ _2"></span>进步<span class="_ _2"></span><span class="ff5">,</span>计<span class="_ _2"></span>算机<span class="_ _2"></span>越来<span class="_ _2"></span>越深<span class="_ _2"></span>入到<span class="_ _2"></span>我们<span class="_ _2"></span>日常<span class="_ _2"></span>的工<span class="_ _2"></span>作学<span class="_ _2"></span>习及</div><div class="t m0 x4 h5 y16 ff2 fs2 fc0 sc0 ls0 ws0">生<span class="_ _2"></span>活<span class="_ _2"></span>中<span class="_ _2"></span><span class="ff5">,<span class="_ _2"></span></span>成<span class="_ _2"></span>为<span class="_ _2"></span>我<span class="_ _2"></span>们<span class="_ _2"></span>日<span class="_ _2"></span>常<span class="_ _2"></span>生<span class="_ _2"></span>活<span class="_ _2"></span>中<span class="_ _2"></span>不<span class="_ _2"></span>可<span class="_ _2"></span>缺<span class="_ _2"></span>少<span class="_ _2"></span>的<span class="_ _2"></span>辅<span class="_ _2"></span>助<span class="_ _2"></span>工<span class="_ _2"></span>具<span class="_ _2"></span>。<span class="_ _2"></span>随<span class="_ _2"></span>着<span class="_ _2"></span>科<span class="_ _2"></span>学<span class="_ _2"></span>技<span class="_ _2"></span>术<span class="_ _2"></span>的<span class="_ _2"></span>不<span class="_ _2"></span>断<span class="_ _2"></span>提<span class="_ _2"></span>高<span class="_ _3"> </span><span class="ff5">,</span></div><div class="t m0 x4 h5 y17 ff2 fs2 fc0 sc0 ls0 ws0">计<span class="_ _2"></span>算<span class="_ _2"></span>机<span class="_ _2"></span>科<span class="_ _2"></span>学<span class="_ _2"></span>日<span class="_ _2"></span>渐<span class="_ _2"></span>成<span class="_ _2"></span>熟<span class="_ _7"></span><span class="ff5">,<span class="_ _2"></span></span>其<span class="_ _2"></span>强<span class="_ _2"></span>大<span class="_ _2"></span>的<span class="_ _2"></span>功<span class="_ _2"></span>能<span class="_ _2"></span>已<span class="_ _2"></span>为<span class="_ _2"></span>人<span class="_ _2"></span>们<span class="_ _2"></span>深<span class="_ _2"></span>刻<span class="_ _2"></span>认<span class="_ _2"></span>识<span class="_ _8"></span><span class="ff5">,<span class="_ _2"></span></span>它<span class="_ _2"></span>已<span class="_ _2"></span>进<span class="_ _2"></span>入<span class="_ _2"></span>人<span class="_ _2"></span>类<span class="_ _2"></span>社<span class="_ _2"></span>会<span class="_ _2"></span>的<span class="_ _2"></span>各</div><div class="t m0 x4 h5 y18 ff2 fs2 fc0 sc0 ls0 ws0">个领域<span class="_ _2"></span>并发挥着<span class="_ _2"></span>越来越<span class="_ _2"></span>重要的作<span class="_ _2"></span>用。它<span class="_ _2"></span>已经深入<span class="_ _2"></span>到日常<span class="_ _2"></span>工作和生<span class="_ _2"></span>活的方<span class="_ _2"></span>方面面<span class="_ _7"></span><span class="ff5">,</span></div><div class="t m0 x4 h5 y19 ff2 fs2 fc0 sc0 ls0 ws0">比如<span class="_ _2"></span>文<span class="_ _2"></span>字处<span class="_ _2"></span>理<span class="_ _2"></span>、信<span class="_ _2"></span>息<span class="_ _2"></span>管理<span class="_ _2"></span>、<span class="_ _2"></span>辅助<span class="_ _2"></span>设<span class="_ _2"></span>计、<span class="_ _2"></span>图<span class="_ _2"></span>形图<span class="_ _2"></span>像<span class="_ _2"></span>处理<span class="_ _2"></span>、<span class="_ _2"></span>教育<span class="_ _2"></span>培<span class="_ _2"></span>训以<span class="_ _2"></span>及<span class="_ _2"></span>游戏<span class="_ _2"></span>娱<span class="_ _2"></span>乐</div><div class="t m0 x4 h5 y1a ff2 fs2 fc0 sc0 ls0 ws0">等。<span class="_ _2"></span>各<span class="_ _2"></span>行各<span class="_ _2"></span>业<span class="_ _2"></span>的人<span class="_ _2"></span>们<span class="_ _2"></span>无须<span class="_ _2"></span>经<span class="_ _2"></span>过特<span class="_ _2"></span>别<span class="_ _2"></span>的训<span class="_ _2"></span>练<span class="_ _2"></span>就能<span class="_ _2"></span>够<span class="_ _2"></span>使用<span class="_ _2"></span>电<span class="_ _2"></span>脑完<span class="_ _2"></span>成<span class="_ _2"></span>许许<span class="_ _2"></span>多<span class="_ _2"></span>多复<span class="_ _2"></span>杂<span class="_ _2"></span>的</div><div class="t m0 x4 h5 y1b ff2 fs2 fc0 sc0 ls0 ws0">工<span class="_ _2"></span>作<span class="_ _2"></span>。<span class="_ _2"></span>然<span class="_ _2"></span>而<span class="_ _7"></span><span class="ff5">,</span>虽<span class="_ _2"></span>然<span class="_ _2"></span>现<span class="_ _2"></span>在<span class="_ _2"></span>世<span class="_ _2"></span>界<span class="_ _2"></span>上<span class="_ _2"></span>已<span class="_ _2"></span>经<span class="_ _2"></span>充<span class="_ _2"></span>满<span class="_ _2"></span>了<span class="_ _2"></span>多<span class="_ _2"></span>如<span class="_ _2"></span>牛<span class="_ _2"></span>毛<span class="_ _2"></span>的<span class="_ _2"></span>各<span class="_ _2"></span>种<span class="_ _2"></span>软<span class="_ _2"></span>件<span class="_ _9"> </span><span class="ff5">,<span class="_ _2"></span></span>但<span class="_ _2"></span>它<span class="_ _2"></span>们<span class="_ _2"></span>依<span class="_ _2"></span>然<span class="_ _2"></span>不<span class="_ _2"></span>能</div><div class="t m0 x4 h5 y1c ff2 fs2 fc0 sc0 ls0 ws0">满足用<span class="_ _2"></span>户的各种<span class="_ _2"></span>特殊需<span class="_ _2"></span>要<span class="ff5">,<span class="_ _2"></span></span>人们还<span class="_ _2"></span>不得不<span class="_ _2"></span>开发适合<span class="_ _2"></span>自己特<span class="_ _2"></span>殊需求的<span class="_ _2"></span>软件。<span class="_ _2"></span>以前开</div><div class="t m0 x4 h5 y1d ff2 fs2 fc0 sc0 ls0 ws0">发<span class="_ _a"> </span><span class="ff5">Windows<span class="_ _a"> </span></span>应用<span class="_ _2"></span>软件<span class="_ _2"></span>是专<span class="_ _2"></span>业人<span class="_ _2"></span>员的<span class="_ _2"></span>工作<span class="_ _2"></span><span class="ff5">,<span class="_ _2"></span></span>需要<span class="_ _2"></span>掌握<span class="_ _2"></span>许多<span class="_ _2"></span>专业<span class="_ _2"></span>知识<span class="_ _2"></span>和经<span class="_ _2"></span>过特<span class="_ _2"></span>殊的</div><div class="t m0 x4 h5 y1e ff2 fs2 fc0 sc0 ls0 ws0">培<span class="_ _2"></span>训<span class="_ _2"></span>才<span class="_ _2"></span>能<span class="_ _2"></span>胜<span class="_ _2"></span>任<span class="_ _2"></span>。<span class="_ _2"></span>现<span class="_ _2"></span>在<span class="_ _2"></span>不<span class="_ _2"></span>同<span class="_ _2"></span>了<span class="_ _7"></span><span class="ff5">,<span class="_ _2"></span></span>即<span class="_ _2"></span>使<span class="_ _2"></span>你<span class="_ _2"></span>没<span class="_ _2"></span>有<span class="_ _2"></span>接<span class="_ _2"></span>受<span class="_ _2"></span>过<span class="_ _2"></span>严<span class="_ _2"></span>格<span class="_ _2"></span>的<span class="_ _2"></span>程<span class="_ _2"></span>序<span class="_ _2"></span>设<span class="_ _2"></span>计<span class="_ _2"></span>训<span class="_ _2"></span>练<span class="_ _9"></span><span class="ff5">,</span>使<span class="_ _2"></span>用<span class="_ _2"></span>各<span class="_ _2"></span>种</div><div class="t m0 x4 h5 y1f ff2 fs2 fc0 sc0 ls0 ws0">可视<span class="_ _2"></span>化<span class="_ _2"></span>编程<span class="_ _2"></span>软<span class="_ _2"></span>件也<span class="_ _2"></span>一<span class="_ _2"></span>样能<span class="_ _2"></span>够<span class="_ _2"></span>开发<span class="_ _2"></span>出<span class="_ _2"></span>功能<span class="_ _2"></span>强<span class="_ _2"></span>大、<span class="_ _2"></span>适<span class="_ _2"></span>合自<span class="_ _2"></span>己<span class="_ _2"></span>特殊<span class="_ _2"></span>需<span class="_ _2"></span>求的<span class="_ _2"></span>应<span class="_ _2"></span>用程<span class="_ _2"></span>序<span class="_ _2"></span>了<span class="_ _7"></span>。</div><div class="t m0 x4 h5 y20 ff2 fs2 fc0 sc0 ls0 ws0">特特<span class="_ _2"></span>别<span class="_ _2"></span>是现<span class="_ _2"></span>在<span class="_ _2"></span>越来<span class="_ _2"></span>越<span class="_ _2"></span>发达<span class="_ _2"></span>的<span class="_ _2"></span>网络<span class="_ _2"></span>,<span class="_ _2"></span>随之<span class="_ _2"></span>而<span class="_ _2"></span>来的<span class="_ _2"></span>是<span class="_ _2"></span>巨大<span class="_ _2"></span>的<span class="_ _2"></span>网络<span class="_ _2"></span>数<span class="_ _2"></span>据传<span class="_ _2"></span>输<span class="_ _2"></span>,这<span class="_ _2"></span>就<span class="_ _2"></span>涉</div><div class="t m0 x4 h5 y21 ff2 fs2 fc0 sc0 ls0 ws0">及到一系列的网络编程技术。</div><div class="t m0 x4 h5 y22 ff5 fs2 fc0 sc0 ls0 ws0"> <span class="_ _2"></span> <span class="_ _2"></span> <span class="ff2">通<span class="_ _2"></span>常程<span class="_ _2"></span>序所<span class="_ _2"></span>使用的<span class="_ _2"></span>每个<span class="_ _b"> </span></span>UDP<span class="_ _a"> </span><span class="ff2">端口都<span class="_ _2"></span>与一<span class="_ _2"></span>个有<span class="_ _2"></span>限大<span class="_ _2"></span>小的<span class="_ _2"></span>输入队<span class="_ _2"></span>列相<span class="_ _2"></span>联系<span class="_ _2"></span>。这</span></div><div class="t m0 x4 h5 y23 ff2 fs2 fc0 sc0 ls0 ws0">意味着,来自不同客户的差不多同时到达的请求将由<span class="_ _b"> </span><span class="ff5">UDP<span class="_ _a"> </span></span>自<span class="ff6">动排</span>队。接<span class="ff6">收</span>到的</div><div class="t m0 x4 h5 y24 ff5 fs2 fc0 sc0 ls0 ws0">UDP<span class="_ _c"> </span><span class="ff2">数<span class="_ _2"></span>据<span class="_ _7"></span>报<span class="_ _2"></span>以<span class="_ _7"></span>其<span class="_ _2"></span>接<span class="_ _7"></span><span class="ff6">收<span class="_ _2"></span>顺<span class="_ _7"></span></span>序<span class="_ _2"></span><span class="ff6">交<span class="_ _7"></span>给<span class="_ _2"></span></span>应<span class="_ _7"></span>用<span class="_ _2"></span>程<span class="_ _7"></span>序<span class="_ _2"></span>(<span class="_ _7"></span>在<span class="_ _2"></span>应<span class="_ _7"></span>用<span class="_ _2"></span>程<span class="_ _7"></span>序<span class="_ _2"></span>要<span class="_ _2"></span>求<span class="_ _7"></span><span class="ff6">交<span class="_ _7"></span>送<span class="_ _2"></span>下<span class="_ _7"></span></span>一<span class="_ _2"></span>个<span class="_ _7"></span>数<span class="_ _2"></span>据<span class="_ _2"></span>报</span></div><div class="t m0 x4 h5 y25 ff2 fs2 fc0 sc0 ls0 ws0">时)。<span class="_ _2"></span><span class="ff5">UDP<span class="_ _a"> </span></span>在一个<span class="_ _2"></span><span class="ff6">较低水平<span class="_ _2"></span></span>上完<span class="_ _2"></span>成了通信<span class="_ _2"></span>,在<span class="_ _2"></span><span class="ff6">收</span>到分<span class="_ _2"></span><span class="ff6">组</span>的时<span class="_ _2"></span><span class="ff6">候</span>没有<span class="_ _2"></span>流<span class="ff6">量控<span class="_ _2"></span>制</span>机</div><div class="t m0 x4 h5 y26 ff6 fs2 fc0 sc0 ls0 ws0">制<span class="ff2">,也没有</span>确<span class="ff2">认机</span>制<span class="ff2">,适用</span>于<span class="ff2">可</span>靠性<span class="ff2">能比</span>较好<span class="ff2">的</span>局<span class="ff2">域网,由</span>于<span class="_ _d"> </span><span class="ff5">UDP<span class="_ _3"> </span></span>采取<span class="ff2">了无</span>连</div><div class="t m0 x4 h5 y27 ff2 fs2 fc0 sc0 ls0 ws0">接方<span class="ff6">式<span class="_ _2"></span></span>,<span class="ff6">因此<span class="_ _2"></span>协议</span>简<span class="_ _2"></span><span class="ff6">单</span>,在<span class="_ _2"></span>一<span class="ff6">些</span>特<span class="_ _2"></span><span class="ff6">定</span>的应<span class="_ _2"></span>用中<span class="_ _2"></span><span class="ff6">协议运<span class="_ _2"></span></span>行<span class="ff6">效率<span class="_ _2"></span></span>高。<span class="_ _7"></span><span class="ff5">UDP<span class="_ _a"> </span></span>使用与一</div><div class="t m0 x4 h5 y28 ff6 fs2 fc0 sc0 ls0 ws0">些<span class="ff2">实时<span class="_ _2"></span>的应用,<span class="_ _2"></span>如<span class="_ _a"> </span><span class="ff5">IP<span class="_ _a"> </span></span>电</span>话<span class="_ _2"></span><span class="ff2">等,它们<span class="_ _2"></span>要求<span class="_ _2"></span></span>源主<span class="ff2">机<span class="_ _2"></span>以</span>恒定<span class="_ _2"></span><span class="ff2">的</span>速率<span class="_ _2"></span><span class="ff2">发</span>送<span class="ff2">时<span class="_ _2"></span>数据,<span class="_ _2"></span>并</span>且</div><div class="t m0 x4 h5 y29 ff2 fs2 fc0 sc0 ls0 ws0">在网<span class="_ _2"></span>络<span class="_ _2"></span>出现<span class="_ _2"></span><span class="ff6">拥<span class="_ _2"></span>塞</span>时<span class="_ _2"></span>可<span class="_ _2"></span>以<span class="_ _2"></span><span class="ff6">丢失<span class="_ _2"></span></span>一<span class="_ _2"></span><span class="ff6">些</span>数<span class="_ _2"></span>据<span class="_ _2"></span>,但<span class="_ _2"></span>是<span class="_ _2"></span><span class="ff6">迟延<span class="_ _2"></span></span>不<span class="_ _2"></span>能<span class="_ _2"></span><span class="ff6">太</span>大<span class="_ _2"></span>。<span class="_ _2"></span><span class="ff6">基于<span class="_ _2"></span></span>这<span class="_ _2"></span><span class="ff6">些</span>特<span class="_ _2"></span><span class="ff6">点<span class="_ _2"></span></span>,流</div><div class="t m0 x4 h5 y2a ff6 fs2 fc0 sc0 ls0 ws0">式<span class="ff2">多</span>媒<span class="ff2">体通信,多</span>播<span class="ff2">等应用在传输</span>层采<span class="ff2">用的就是<span class="_ _a"> </span><span class="ff5">UDP<span class="_ _3"> </span></span></span>协议<span class="ff2">。</span></div><div class="t m0 x7 h5 y2b ff6 fs2 fc0 sc0 ls0 ws0">因<span class="_ _2"></span><span class="ff2">为<span class="_ _2"></span></span>本<span class="_ _2"></span><span class="ff2">人<span class="_ _2"></span>能<span class="_ _7"></span></span>力<span class="ff2">有<span class="_ _7"></span>限<span class="_ _2"></span><span class="ff5">,<span class="_ _2"></span></span></span>加<span class="_ _2"></span><span class="ff2">上<span class="_ _2"></span>时<span class="_ _2"></span></span>间<span class="_ _7"></span>紧迫<span class="_ _7"></span><span class="ff5">,<span class="_ _2"></span><span class="ff2">所<span class="_ _2"></span>以<span class="_ _2"></span>设<span class="_ _2"></span>计<span class="_ _2"></span>出<span class="_ _7"></span>来的<span class="_ _7"></span></span></span>本<span class="ff2">系<span class="_ _7"></span>统可<span class="_ _7"></span>能功<span class="_ _2"></span>能<span class="_ _2"></span>比<span class="_ _7"></span></span>较<span class="_ _2"></span><span class="ff2">简</span></div><div class="t m0 x4 h5 y2c ff6 fs2 fc0 sc0 ls0 ws0">单<span class="ff5">,<span class="_ _2"></span></span>另<span class="_ _2"></span>外本<span class="_ _2"></span><span class="ff2">系<span class="_ _2"></span>统是<span class="_ _2"></span></span>单<span class="_ _2"></span><span class="ff2">机<span class="_ _2"></span></span>版<span class="_ _2"></span><span class="ff5">,<span class="_ _2"></span><span class="ff2">不能<span class="_ _2"></span>实<span class="_ _2"></span>现网<span class="_ _2"></span>络<span class="_ _2"></span></span></span>互<span class="ff2">联<span class="_ _2"></span></span>操<span class="_ _2"></span><span class="ff2">作<span class="_ _7"></span><span class="ff5">,</span>这</span>些<span class="_ _2"></span><span class="ff2">都<span class="_ _2"></span>有</span>待<span class="_ _2"></span>于<span class="_ _2"></span><span class="ff2">我<span class="_ _2"></span>在以<span class="_ _2"></span></span>后<span class="_ _2"></span><span class="ff2">的工<span class="_ _2"></span>作</span></div><div class="t m0 x4 h5 y2d ff2 fs2 fc0 sc0 ls0 ws0">学习中进一步<span class="ff6">改</span>进。</div><div class="t m0 x4 h5 y2e ff2 fs2 fc0 sc1 ls0 ws0">(<span class="ff4 sc0">2</span>)<span class="_ _6"> </span><span class="ff4 sc0">UDP<span class="_ _a"> </span></span>简介</div><div class="t m0 x8 h5 y2f ff5 fs2 fc0 sc0 ls0 ws0">UDP<span class="_ _a"> </span><span class="ff6">协议<span class="_ _2"></span><span class="ff2">是<span class="_ _2"></span></span>英<span class="_ _2"></span><span class="ff2">文<span class="_ _a"> </span></span></span>User <span class="_ _2"></span>Datagram <span class="_ _2"></span>Protocol<span class="_ _a"> </span><span class="ff2">的<span class="_ _2"></span><span class="ff6">缩写<span class="_ _2"></span></span>,<span class="_ _2"></span>即用<span class="_ _2"></span>户<span class="_ _2"></span>数据<span class="_ _2"></span>报<span class="_ _2"></span><span class="ff6">协<span class="_ _2"></span>议</span>,</span></div><div class="t m0 x4 h5 y30 ff6 fs2 fc0 sc0 ls0 ws0">主<span class="ff2">要<span class="_ _2"></span>用<span class="_ _2"></span>来</span>支<span class="_ _2"></span>持<span class="_ _2"></span>那些<span class="_ _2"></span><span class="ff2">需<span class="_ _2"></span>要在<span class="_ _2"></span>计<span class="_ _2"></span>算机<span class="_ _2"></span>之<span class="_ _2"></span></span>间<span class="_ _2"></span><span class="ff2">传输<span class="_ _2"></span>数<span class="_ _2"></span>据的<span class="_ _2"></span>网<span class="_ _2"></span>络应<span class="_ _2"></span>用<span class="_ _2"></span>。<span class="_ _2"></span></span>包括<span class="_ _2"></span><span class="ff2">网<span class="_ _2"></span>络视<span class="_ _2"></span></span>频<span class="_ _2"></span><span class="ff2">会</span>议</div><div class="t m0 x4 h5 y31 ff2 fs2 fc0 sc0 ls0 ws0">系统<span class="_ _2"></span>在内<span class="_ _2"></span>的<span class="ff6">众<span class="_ _2"></span></span>多的<span class="_ _2"></span>客户<span class="_ _7"></span><span class="ff5">/</span>服<span class="_ _2"></span>务器<span class="_ _2"></span><span class="ff6">模式<span class="_ _2"></span></span>的网<span class="_ _2"></span>络应<span class="_ _2"></span>用都<span class="_ _2"></span>需要<span class="_ _2"></span>使用<span class="_ _c"> </span><span class="ff5">UDP<span class="_ _a"> </span><span class="ff6">协<span class="_ _2"></span>议</span></span>。<span class="_ _2"></span><span class="ff5">UDP<span class="_ _a"> </span><span class="ff6">协</span></span></div><div class="t m0 x4 h5 y32 ff6 fs2 fc0 sc0 ls0 ws0">议从<span class="_ _2"></span>问<span class="_ _2"></span><span class="ff2">世</span>至<span class="_ _2"></span>今<span class="_ _2"></span><span class="ff2">已经<span class="_ _2"></span></span>被<span class="_ _2"></span><span class="ff2">使<span class="_ _2"></span>用了<span class="_ _2"></span></span>很<span class="_ _2"></span><span class="ff2">多</span>年<span class="_ _2"></span><span class="ff2">,<span class="_ _2"></span>虽然<span class="_ _2"></span>其<span class="_ _2"></span></span>最初<span class="_ _2"></span><span class="ff2">的<span class="_ _2"></span></span>光彩<span class="_ _2"></span><span class="ff2">已<span class="_ _2"></span>经<span class="_ _2"></span></span>被<span class="ff2">一<span class="_ _2"></span></span>些<span class="_ _2"></span><span class="ff2">类</span>似<span class="_ _2"></span>协<span class="_ _2"></span>议<span class="ff2">所</span></div><div class="t m0 x4 h5 y33 ff6 fs2 fc0 sc0 ls0 ws0">掩盖<span class="ff2">,<span class="_ _2"></span>但是即使<span class="_ _2"></span>是在<span class="_ _2"></span></span>今天<span class="ff2">,<span class="_ _2"></span><span class="ff5">U<span class="_ _2"></span>DP<span class="_ _a"> </span></span></span>仍<span class="ff2">然不</span>失<span class="ff2">为<span class="_ _2"></span>一</span>项非<span class="_ _2"></span><span class="ff2">常实用<span class="_ _2"></span>和可行的<span class="_ _2"></span>网络传<span class="_ _2"></span>输<span class="_ _2"></span></span>层</div><div class="t m0 x4 h5 y34 ff6 fs2 fc0 sc0 ls0 ws0">协议<span class="ff2">。</span></div><div class="t m0 x7 h5 y35 ff5 fs2 fc0 sc0 ls0 ws0">UDP<span class="_ _a"> </span><span class="ff6">协议<span class="ff2">的</span>几<span class="ff2">个特</span>性<span class="ff2">:</span></span></div><div class="t m0 x8 h5 y36 ff5 fs2 fc0 sc0 ls0 ws0">1<span class="ff2">)<span class="_ _0"> </span></span>UDP<span class="_ _a"> </span><span class="ff2">是<span class="_ _2"></span>一<span class="_ _2"></span>个<span class="_ _2"></span>无<span class="_ _7"></span><span class="ff6">连</span>接<span class="_ _2"></span><span class="ff6">协<span class="_ _2"></span>议<span class="_ _2"></span></span>,<span class="_ _2"></span>传<span class="_ _2"></span>输<span class="_ _2"></span>数<span class="_ _2"></span>据<span class="_ _2"></span>之<span class="_ _2"></span>前<span class="_ _2"></span><span class="ff6">源<span class="_ _2"></span></span>端<span class="_ _2"></span>和<span class="_ _7"></span><span class="ff6">终</span>端<span class="_ _2"></span>不<span class="_ _2"></span><span class="ff6">建<span class="_ _2"></span>立<span class="_ _2"></span>连<span class="_ _2"></span></span>接<span class="_ _2"></span>,<span class="_ _2"></span><span class="ff6">当<span class="_ _2"></span></span>它</span></div><div class="t m0 x4 h5 y37 ff2 fs2 fc0 sc0 ls0 ws0">想传<span class="_ _2"></span><span class="ff6">送<span class="_ _2"></span></span>时就<span class="_ _2"></span>简<span class="_ _2"></span><span class="ff6">单地<span class="_ _2"></span>去<span class="_ _2"></span>抓取<span class="_ _2"></span></span>来<span class="_ _2"></span>自<span class="_ _2"></span>应用<span class="_ _2"></span>程<span class="_ _2"></span>序的<span class="_ _2"></span>数<span class="_ _2"></span>据,<span class="_ _2"></span>并<span class="_ _2"></span><span class="ff6">尽<span class="_ _2"></span></span>可能<span class="_ _2"></span><span class="ff6">快<span class="_ _2"></span>地把<span class="_ _2"></span></span>它<span class="_ _2"></span><span class="ff6">扔</span>到<span class="_ _2"></span>网<span class="_ _2"></span>络上<span class="_ _7"></span>。</div><div class="t m0 x4 h5 y38 ff2 fs2 fc0 sc0 ls0 ws0">在发<span class="ff6">送<span class="_ _2"></span></span>端,<span class="_ _2"></span><span class="ff5">UDP<span class="_ _a"> </span></span>传<span class="ff6">送</span>数据的<span class="_ _2"></span><span class="ff6">速度<span class="_ _2"></span>仅仅</span>是<span class="_ _2"></span>受应用程<span class="_ _2"></span>序生成<span class="_ _2"></span>数据的<span class="_ _2"></span><span class="ff6">速度<span class="_ _2"></span></span>、计算<span class="_ _2"></span>机的</div><div class="t m0 x4 h5 y39 ff2 fs2 fc0 sc0 ls0 ws0">能<span class="ff6">力</span>和<span class="_ _2"></span>传输<span class="ff6">带<span class="_ _2"></span>宽</span>的限<span class="_ _2"></span><span class="ff6">制;</span>在<span class="_ _2"></span>接<span class="ff6">收</span>端<span class="_ _2"></span>,<span class="_ _2"></span><span class="ff5">UDP<span class="_ _a"> </span><span class="ff6">把</span></span>每个<span class="_ _2"></span><span class="ff6">消</span>息<span class="ff6">段<span class="_ _2"></span>放</span>在队<span class="_ _2"></span>列中,<span class="_ _2"></span>应用程序</div><div class="t m0 x4 h5 y3a ff2 fs2 fc0 sc0 ls0 ws0">每<span class="ff6">次从</span>队列中<span class="ff6">读</span>一个<span class="ff6">消</span>息<span class="ff6">段</span>。</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>