📄 vlan1.htm
字号:
<table cellpadding=0 cellspacing=0 width="100%">
<tr>
<td><![endif]>
<div>
<p class=MsoNormal><b style='mso-bidi-font-weight:normal'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman";color:blue'>……</span><span lang=EN-US style='color:blue'><o:p></o:p></span></b></p>
</div>
<![if !mso]></td>
</tr>
</table>
<![endif]></v:textbox>
</v:shape><v:line id="_x0000_s1467" style='position:absolute' from="3000,7993"
to="3360,8617" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1468" style='position:absolute;flip:y' from="3960,7837"
to="3961,8305" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1469" style='position:absolute' from="4500,9085"
to="4860,9709" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1470" style='position:absolute' from="6840,11893"
to="7380,12517" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1471" style='position:absolute' from="7560,11581"
to="8460,12361" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1472" style='position:absolute;flip:x' from="2880,11893"
to="3240,12517" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1473" style='position:absolute;flip:x' from="4320,11893"
to="4321,12517" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1474" style='position:absolute;flip:x' from="4500,10489"
to="5400,11269" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1475" style='position:absolute' from="4860,8461"
to="6120,8462" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1476" style='position:absolute' from="4860,11425"
to="6120,11426" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1477" style='position:absolute;flip:y' from="7380,7993"
to="8280,8773" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:line id="_x0000_s1478" style='position:absolute;flip:y' from="7020,7837"
to="7380,8305" strokecolor="red">
<v:stroke endarrow="block"/>
</v:line><v:shapetype id="_x0000_t47" coordsize="21600,21600" o:spt="47"
adj="-8280,24300,-1800,4050" path="m@0@1l@2@3nfem,l21600,r,21600l,21600xe">
<v:stroke joinstyle="miter"/>
<v:formulas>
<v:f eqn="val #0"/>
<v:f eqn="val #1"/>
<v:f eqn="val #2"/>
<v:f eqn="val #3"/>
</v:formulas>
<v:path arrowok="t" o:extrusionok="f" gradientshapeok="t" o:connecttype="custom"
o:connectlocs="@0,@1;10800,0;10800,21600;0,10800;21600,10800"/>
<v:handles>
<v:h position="#0,#1"/>
<v:h position="#2,#3"/>
</v:handles>
<o:callout v:ext="edit" type="oneSegment" on="t"/>
</v:shapetype><v:shape id="_x0000_s1479" type="#_x0000_t47" style='position:absolute;
left:3000;top:9709;width:1578;height:780' adj="-2012,-52255,-1643,4985,8213,12960,8213,12960"
strokecolor="red">
<v:fill opacity="0"/>
<v:textbox>
<![if !mso]>
<table cellpadding=0 cellspacing=0 width="100%">
<tr>
<td><![endif]>
<div>
<p class=MsoNormal><b style='mso-bidi-font-weight:normal'><span
lang=EN-US style='color:red'>ARP Request<o:p></o:p></span></b></p>
<p class=MsoNormal align=center style='text-align:center'><b
style='mso-bidi-font-weight:normal'><span lang=EN-US style='color:red'>Broadcast<o:p></o:p></span></b></p>
</div>
<![if !mso]></td>
</tr>
</table>
<![endif]></v:textbox>
</v:shape><v:shape id="_x0000_s1480" type="#_x0000_t202" style='position:absolute;
left:7500;top:9085;width:2340;height:1404' stroked="f">
<v:textbox>
<![if !mso]>
<table cellpadding=0 cellspacing=0 width="100%">
<tr>
<td><![endif]>
<div>
<p class=MsoNormal><span class=GramE><b style='mso-bidi-font-weight:normal'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>广播帧会传播</span></b></span><b style='mso-bidi-font-weight:
normal'><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>到网络中的每一台主机，</span><span
lang=EN-US><o:p></o:p></span></b></p>
<p class=MsoNormal><b style='mso-bidi-font-weight:normal'><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>并且对每一台计算机的</span><span lang=EN-US>CPU</span></b><b
style='mso-bidi-font-weight:normal'><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>造成负担。</span><span
lang=EN-US><o:p></o:p></span></b></p>
</div>
<![if !mso]></td>
</tr>
</table>
<![endif]></v:textbox>
</v:shape><w:wrap type="none"/>
<w:anchorlock/>
</v:group><![endif]--><![if !vml]><img width=544 height=468
src="VLAN1.files/image006.gif" v:shapes="_x0000_s1432 _x0000_s1433 _x0000_s1434 _x0000_s1435 _x0000_s1436 _x0000_s1437 _x0000_s1438 _x0000_s1439 _x0000_s1440 _x0000_s1441 _x0000_s1442 _x0000_s1443 _x0000_s1444 _x0000_s1445 _x0000_s1446 _x0000_s1447 _x0000_s1448 _x0000_s1449 _x0000_s1450 _x0000_s1451 _x0000_s1452 _x0000_s1453 _x0000_s1454 _x0000_s1455 _x0000_s1456 _x0000_s1457 _x0000_s1458 _x0000_s1459 _x0000_s1460 _x0000_s1461 _x0000_s1462 _x0000_s1463 _x0000_s1464 _x0000_s1465 _x0000_s1466 _x0000_s1467 _x0000_s1468 _x0000_s1469 _x0000_s1470 _x0000_s1471 _x0000_s1472 _x0000_s1473 _x0000_s1474 _x0000_s1475 _x0000_s1476 _x0000_s1477 _x0000_s1478 _x0000_s1479 _x0000_s1480"><![endif]></span><!--[if mso & !supportInlineShapes & supportFields]><span
lang=EN-US><v:shape id="_x0000_i1026" type="#_x0000_t75" style='width:408pt;
height:351pt'>
<v:imagedata croptop="-65520f" cropbottom="65520f"/>
</v:shape><span style='mso-element:field-end'></span></span><![endif]--></p>
<p class=MsoNormal><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>请大家注意一下，这个</span><span lang=EN-US>ARP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>请求原本是为了获得计算机</span><span lang=EN-US>B</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>的</span><span lang=EN-US>MAC</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>地址而发出的。也就是说：<span
style='color:blue'>只要计算机</span></span><span lang=EN-US style='color:blue'>B</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman";color:blue'>能收到就万事大吉了</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>。可是事实上，数据帧却传遍整个网络，导致所有的计算机都收到了它。如此一来，一方面广播信息消耗了网络整体的带宽，另一方面，收到广播信息的计算机还要消耗一部分</span><span
lang=EN-US>CPU</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>时间来对它进行处理。<span style='color:red'>造成了网络带宽和</span></span><span
lang=EN-US style='color:red'>CPU</span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman";color:red'>运算能力的大量无谓消耗</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>。</span></p>
<p class=MsoNormal><span lang=EN-US style='font-size:13.5pt'><br>
</span><b style='mso-bidi-font-weight:normal'><span style='font-size:12.0pt;
font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman";color:red'>广播信息是那么经常发出的吗？</span></b></p>
<p class=MsoNormal><span style='mso-bidi-font-size:10.5pt;font-family:宋体;
mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>读到这里，您也许会问：广播信息真是那么频繁出现的吗？</span><span
lang=EN-US style='mso-bidi-font-size:10.5pt'><o:p></o:p></span></p>
<p class=MsoNormal><span style='mso-bidi-font-size:10.5pt;font-family:宋体;
mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>答案是：是的！<span
style='color:red'>实际上<span class=GramE>广播帧会非常</span>频繁地出现</span>。利用</span><span
lang=EN-US style='mso-bidi-font-size:10.5pt'>TCP/IP</span><span
style='mso-bidi-font-size:10.5pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>协议<span class=GramE>栈</span>通信时，除了前面出现的</span><span
lang=EN-US style='mso-bidi-font-size:10.5pt'>ARP</span><span style='mso-bidi-font-size:
10.5pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>外，还有可能需要发出</span><span lang=EN-US style='mso-bidi-font-size:
10.5pt'>DHCP</span><span style='mso-bidi-font-size:10.5pt;font-family:宋体;
mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>、</span><span
lang=EN-US style='mso-bidi-font-size:10.5pt'>RIP</span><span style='mso-bidi-font-size:
10.5pt;font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>等很多其他类型的广播信息。</span><span lang=EN-US style='mso-bidi-font-size:
10.5pt'><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>ARP</span><span style='font-family:宋体;
mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>广播，是在需要与其他主机通信时发出的。当客户机请求</span><span
lang=EN-US>DHCP</span><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>服务器分配</span><span lang=EN-US>IP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>地址时</span></p>
<p class=MsoNormal><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>，就必须发出</span><span lang=EN-US>DHCP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>的广播。而使用</span><span lang=EN-US>RIP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>作为路由协议时，每隔</span><span lang=EN-US>30</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>秒路由器都会对邻近的其他路由器广播一次路由信息。</span><span lang=EN-US>RIP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>以外的其他路由协议使用多播传输路由信息，这也会被交换机转发（</span><span lang=EN-US>Flooding</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>）。除了</span><span lang=EN-US>TCP/IP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>以外，</span><span lang=EN-US>NetBEUI</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>、</span><span lang=EN-US>IPX</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>和</span><span
lang=EN-US>Apple Talk</span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>等协议也经常需要用到广播。例如在</span><span
lang=EN-US>Windows</span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>下双击打开“网络计算机”时就会发出广播（多播）信息。（</span><span
lang=EN-US>Windows XP</span><span style='font-family:宋体;mso-ascii-font-family:
"Times New Roman";mso-hansi-font-family:"Times New Roman"'>除外……）</span></p>
<p class=MsoNormal><span style='font-family:宋体;mso-ascii-font-family:"Times New Roman";
mso-hansi-font-family:"Times New Roman"'>总之，广播就在我们身边。下面是一些常见的广播通信：</span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:21.0pt;text-indent:-21.0pt;mso-list:l1 level1 lfo3;
tab-stops:list 21.0pt'><![if !supportLists]><span lang=EN-US style='font-family:
Wingdings;mso-fareast-font-family:Wingdings;mso-bidi-font-family:Wingdings'><span
style='mso-list:Ignore'>l<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>ARP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>请求：建立</span><span lang=EN-US>IP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>地址和</span><span lang=EN-US>MAC</span><span style='font-family:
宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman"'>地址的映射关系。</span></p>
<p class=MsoNormal style='margin-left:21.0pt;text-indent:-21.0pt;mso-list:l1 level1 lfo3;
tab-stops:list 21.0pt'><![if !supportLists]><span lang=EN-US style='font-family:
Wingdings;mso-fareast-font-family:Wingdings;mso-bidi-font-family:Wingdings'><span
style='mso-list:Ignore'>l<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>RIP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>：一种路由协议。</span></p>
<p class=MsoNormal style='margin-left:21.0pt;text-indent:-21.0pt;mso-list:l1 level1 lfo3;
tab-stops:list 21.0pt'><![if !supportLists]><span lang=EN-US style='font-family:
Wingdings;mso-fareast-font-family:Wingdings;mso-bidi-font-family:Wingdings'><span
style='mso-list:Ignore'>l<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>DHCP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>：用于自动设定</span><span lang=EN-US>IP</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>地址的协议。</span></p>
<p class=MsoNormal style='margin-left:21.0pt;text-indent:-21.0pt;mso-list:l1 level1 lfo3;
tab-stops:list 21.0pt'><![if !supportLists]><span lang=EN-US style='font-family:
Wingdings;mso-fareast-font-family:Wingdings;mso-bidi-font-family:Wingdings'><span
style='mso-list:Ignore'>l<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>NetBEUI</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>：</span><span lang=EN-US>Windows</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>下使用的网络协议。</span></p>
<p class=MsoNormal style='margin-left:21.0pt;text-indent:-21.0pt;mso-list:l1 level1 lfo3;
tab-stops:list 21.0pt'><![if !supportLists]><span lang=EN-US style='font-family:
Wingdings;mso-fareast-font-family:Wingdings;mso-bidi-font-family:Wingdings'><span
style='mso-list:Ignore'>l<span style='font:7.0pt "Times New Roman"'>
</span></span></span><![endif]><span lang=EN-US>IPX</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>：</span><span lang=EN-US>Novell Netware</span><span
style='font-family:宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:
"Times New Roman"'>使用的网络协议。</span></p>
<p class=MsoNormal style='margin-left:21.0pt;text-indent:-21.0pt;mso-list:l1 level1 lfo3;
tab-stops:list 21.0pt'><![if !su⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -