{"id":1926,"date":"2026-04-15T20:29:24","date_gmt":"2026-04-15T12:29:24","guid":{"rendered":"http:\/\/www.preluna.xyz\/?p=1926"},"modified":"2026-04-15T21:34:15","modified_gmt":"2026-04-15T13:34:15","slug":"%e5%b1%80%e5%9f%9f%e7%bd%91-%e4%bb%a5%e5%a4%aa%e7%bd%91-csma-cd-%e9%ab%98%e9%80%9f%e4%bb%a5%e5%a4%aa%e7%bd%91-csma-ca-vlan","status":"publish","type":"post","link":"http:\/\/www.preluna.xyz\/index.php\/2026\/04\/15\/%e5%b1%80%e5%9f%9f%e7%bd%91-%e4%bb%a5%e5%a4%aa%e7%bd%91-csma-cd-%e9%ab%98%e9%80%9f%e4%bb%a5%e5%a4%aa%e7%bd%91-csma-ca-vlan\/preluna\/text\/","title":{"rendered":"\u5c40\u57df\u7f51\u2014\u4ee5\u592a\u7f51\u2014CSMA\/CD\u2014\u9ad8\u901f\u4ee5\u592a\u7f51\u2014CSMA\/CA\u2014VLAN"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">\u8fd9\u4e00\u5757\u600e\u4e48\u4e32\u8d77\u6765\u7406\u89e3<\/h2>\n\n\n\n<p>\u6570\u636e\u94fe\u8def\u5c42\u91cc\uff0c\u5c40\u57df\u7f51\u8fd9\u4e00\u7ae0\u8868\u9762\u4e0a\u77e5\u8bc6\u70b9\u5f88\u591a\uff0c\u5b9e\u9645\u4e0a\u4e3b\u7ebf\u5f88\u6e05\u695a\uff1a\u5148\u8ba4\u8bc6\u5c40\u57df\u7f51\u662f\u4ec0\u4e48\uff0c\u518d\u770b\u6700\u5178\u578b\u7684\u5c40\u57df\u7f51\u2014\u2014\u4ee5\u592a\u7f51\uff1b\u4ee5\u592a\u7f51\u7684\u6838\u5fc3\u53c8\u5206\u6210\u4e24\u90e8\u5206\uff0c\u4e00\u90e8\u5206\u662f\u201c\u5e27\u600e\u4e48\u5199\u3001\u5730\u5740\u600e\u4e48\u7f16\u201d\uff0c\u53e6\u4e00\u90e8\u5206\u662f\u201c\u591a\u53f0\u673a\u5668\u600e\u4e48\u4e89\u7740\u53d1\u201d\uff0c\u8fd9\u5c31\u843d\u5230\u4e86 MAC \u5730\u5740\u548c\u4ecb\u8d28\u8bbf\u95ee\u63a7\u5236\u534f\u8bae\u4e0a\u3002\u518d\u5f80\u540e\uff0c\u9ad8\u901f\u4ee5\u592a\u7f51\u5176\u5b9e\u662f\u5728\u7ee7\u627f\u4ee5\u592a\u7f51\u57fa\u672c\u683c\u5f0f\u7684\u524d\u63d0\u4e0b\u4e0d\u65ad\u63d0\u901f\uff1b\u65e0\u7ebf\u5c40\u57df\u7f51\u56e0\u4e3a\u7269\u7406\u73af\u5883\u4e0d\u540c\uff0c\u4ecb\u8d28\u8bbf\u95ee\u63a7\u5236\u5c31\u4ece CSMA\/CD \u6362\u6210\u4e86 CSMA\/CA\uff1b\u6700\u540e VLAN \u5219\u662f\u5728\u4ea4\u6362\u5f0f\u4ee5\u592a\u7f51\u73af\u5883\u91cc\u7ee7\u7eed\u505a\u903b\u8f91\u5212\u5206\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u8fd9\u4e00\u7ae0\u771f\u6b63\u8981\u6293\u7684\u662f\u4e00\u6761\u7ebf\uff1a<\/p>\n\n\n\n<p>\u5c40\u57df\u7f51\u57fa\u672c\u6982\u5ff5 \u2192 \u4ee5\u592a\u7f51\u4e0e IEEE 802.3 \u2192 MAC \u5730\u5740 \u2192 CSMA\/CD \u2192 \u6700\u77ed\u5e27\u957f\u4e0e\u9000\u907f \u2192 \u9ad8\u901f\u4ee5\u592a\u7f51 \u2192 \u65e0\u7ebf\u5c40\u57df\u7f51 CSMA\/CA \u2192 VLAN<\/p>\n\n\n\n<p>\u53ea\u8981\u8fd9\u6761\u7ebf\u987a\u4e86\uff0c\u540e\u9762\u7684\u5224\u65ad\u9898\u3001\u8ba1\u7b97\u9898\u548c\u6982\u5ff5\u9898\u5c31\u4e0d\u4f1a\u6563\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u5c40\u57df\u7f51\u7684\u57fa\u672c\u6982\u5ff5\uff1a\u4e09\u4e2a\u8981\u7d20\u5230\u5e95\u662f\u4ec0\u4e48<\/h2>\n\n\n\n<p>408 \u548c\u56fd\u5185\u6559\u6750\u91cc\uff0c\u5c40\u57df\u7f51\u901a\u5e38\u6293\u4e09\u4e2a\u57fa\u672c\u8981\u7d20\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u7f51\u7edc\u62d3\u6251<\/li>\n\n\n\n<li>\u4f20\u8f93\u4ecb\u8d28<\/li>\n\n\n\n<li>\u4ecb\u8d28\u8bbf\u95ee\u63a7\u5236\u65b9\u5f0f<\/li>\n<\/ol>\n\n\n\n<p>\u7f51\u7edc\u62d3\u6251\u8bf4\u7684\u662f\u8fde\u63a5\u5f62\u6001\uff0c\u6bd4\u5982\u603b\u7ebf\u578b\u3001\u661f\u578b\u3001\u73af\u578b\u3002<br>\u4f20\u8f93\u4ecb\u8d28\u8bf4\u7684\u662f\u9760\u4ec0\u4e48\u4f20\uff0c\u53cc\u7ede\u7ebf\u3001\u540c\u8f74\u7535\u7f06\u3001\u5149\u7ea4\u3001\u65e0\u7ebf\u7535\u6ce2\u3002<br>\u4ecb\u8d28\u8bbf\u95ee\u63a7\u5236\u65b9\u5f0f\u8bf4\u7684\u662f\u591a\u53f0\u4e3b\u673a\u5171\u7528\u4fe1\u9053\u65f6\uff0c\u8c01\u5148\u53d1\u3001\u600e\u4e48\u9632\u51b2\u7a81\u3001\u51b2\u7a81\u540e\u600e\u4e48\u529e\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e09\u4e2a\u8981\u7d20\u91cc\uff0c\u8003\u8bd5\u6700\u5bb9\u6613\u53cd\u590d\u8003\u7684\u662f\u7b2c\u4e09\u4e2a\uff0c\u4e5f\u5c31\u662f\u4ecb\u8d28\u8bbf\u95ee\u63a7\u5236\u3002\u56e0\u4e3a\u5c40\u57df\u7f51\u7684\u5178\u578b\u7279\u70b9\u5c31\u662f\u201c\u5171\u4eab\u4fe1\u9053\u201d\u6216\u8005\u201c\u5e7f\u64ad\u4fe1\u9053\u201d\uff0c\u4e00\u65e6\u591a\u53f0\u4e3b\u673a\u540c\u65f6\u8981\u53d1\uff0c\u5c31\u4e00\u5b9a\u4f1a\u51fa\u73b0\u534f\u8c03\u95ee\u9898\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4ee5\u592a\u7f51\u4e0e IEEE 802.3\uff1a\u8003\u7814\u91cc\u600e\u4e48\u533a\u5206<\/h2>\n\n\n\n<p>\u4ece\u8003\u8bd5\u89d2\u5ea6\u770b\uff0c\u6700\u5e38\u89c1\u7684\u8bf4\u6cd5\u662f\uff1a<\/p>\n\n\n\n<p>\u4ee5\u592a\u7f51\u662f\u76ee\u524d\u5e94\u7528\u6700\u5e7f\u6cdb\u7684\u5c40\u57df\u7f51\u6280\u672f\u3002<br>IEEE 802.3 \u662f\u4ee5\u592a\u7f51\u7684\u6807\u51c6\u5316\u7248\u672c\u3002<\/p>\n\n\n\n<p>\u4f46\u505a\u9898\u65f6\u8fd8\u8981\u77e5\u9053\u4e00\u4e2a\u7ec6\u8282\uff1a<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. Ethernet II \u4e0e IEEE 802.3 \u7684\u5173\u952e\u5dee\u522b<\/h3>\n\n\n\n<p>\u6700\u4e3b\u8981\u533a\u522b\u5728\u5e27\u4e2d\u201c\u7c7b\u578b\/\u957f\u5ea6\u201d\u90a3\u4e2a\u5b57\u6bb5\u7684\u542b\u4e49\u4e0d\u540c\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Ethernet II\uff1a\u8be5\u5b57\u6bb5\u8868\u793a\u201c\u7c7b\u578b\u201d\uff0c\u6307\u51fa\u4e0a\u5c42\u662f\u4ec0\u4e48\u534f\u8bae\uff0c\u6bd4\u5982 IP<\/li>\n\n\n\n<li>IEEE 802.3\uff1a\u8be5\u5b57\u6bb5\u8868\u793a\u201c\u957f\u5ea6\u201d\uff0c\u4e0a\u5c42\u534f\u8bae\u7c7b\u578b\u7531 LLC \u5b50\u5c42\u8fdb\u4e00\u6b65\u8bf4\u660e<\/li>\n<\/ul>\n\n\n\n<p>\u4e0d\u8fc7\u5728\u8003\u7814\u91cc\uff0c\u5f88\u591a\u9898\u4e0d\u4f1a\u6b7b\u6263\u8fd9\u4e24\u4e2a\u683c\u5f0f\u7684\u5de5\u7a0b\u7ec6\u8282\uff0c\u5f80\u5f80\u76f4\u63a5\u628a\u201c\u4ee5\u592a\u7f51\u201d\u548c\u201cIEEE 802.3\u201d\u6df7\u7740\u8bf4\u3002\u505a\u9898\u65f6\u4e00\u822c\u9ed8\u8ba4\u5b83\u4eec\u662f\u540c\u4e00\u7c7b\u5c40\u57df\u7f51\u6280\u672f\uff0c\u53ea\u5728\u9898\u76ee\u4e13\u95e8\u6bd4\u8f83\u5e27\u683c\u5f0f\u65f6\u518d\u7ec6\u5206\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u4ea4\u6362\u6280\u672f\u4e0a\uff0c\u4ee5\u592a\u7f51\u91c7\u7528\u4ec0\u4e48\u6280\u672f<\/h3>\n\n\n\n<p>\u8fd9\u9898\u5f88\u5bb9\u6613\u88ab\u95ee\u6210\u5224\u65ad\u6216\u9009\u62e9\u3002<\/p>\n\n\n\n<p>\u4ece\u201c\u4fe1\u9053\u5171\u4eab\u65b9\u5f0f\u201d\u89d2\u5ea6\u8bf4\uff0c\u4f20\u7edf\u4ee5\u592a\u7f51\u91c7\u7528<strong>\u5e7f\u64ad\u901a\u4fe1\u65b9\u5f0f<\/strong>\u3002<br>\u4ece\u201c\u8f6c\u53d1\u5355\u4f4d\u201d\u89d2\u5ea6\u8bf4\uff0c\u4ee5\u592a\u7f51\u5c5e\u4e8e<strong>\u5206\u7ec4\u4ea4\u6362<\/strong>\u3002<br>\u4ece\u201c\u73b0\u4ee3\u7ec4\u7f51\u5f62\u6001\u201d\u770b\uff0c\u4ea4\u6362\u5f0f\u4ee5\u592a\u7f51\u9760<strong>\u4e8c\u5c42\u4ea4\u6362\u673a<\/strong>\u8fdb\u884c\u5e27\u8f6c\u53d1\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u505a\u9898\u4e00\u5b9a\u770b\u9898\u5e72\u95ee\u7684\u662f\u54ea\u4e00\u4e2a\u89d2\u5ea6\u3002<br>\u5982\u679c\u9898\u76ee\u95ee\u201c\u5c40\u57df\u7f51\u6309\u4ea4\u6362\u6280\u672f\u5206\u7c7b\uff0c\u4ee5\u592a\u7f51\u5c5e\u4e8e\u4ec0\u4e48\u201d\uff0c\u5e38\u7b54\u201c\u5e7f\u64ad\u5f0f\u7f51\u7edc\u201d\u3002<br>\u5982\u679c\u9898\u76ee\u628a\u7535\u8def\u4ea4\u6362\u3001\u62a5\u6587\u4ea4\u6362\u3001\u5206\u7ec4\u4ea4\u6362\u653e\u4e00\u8d77\u6bd4\u8f83\uff0c\u90a3\u5e94\u7b54\u201c\u5206\u7ec4\u4ea4\u6362\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">10Base-5 \u8fd9\u7c7b\u540d\u79f0\u600e\u4e48\u8bb0<\/h2>\n\n\n\n<p>\u8fd9\u7c7b\u540d\u79f0\u662f\u6807\u51c6\u547d\u540d\u6cd5\uff0c\u975e\u5e38\u559c\u6b22\u51fa\u9009\u62e9\u9898\u3002<\/p>\n\n\n\n<p>\u4ee5 <code>10Base-5<\/code> \u4e3a\u4f8b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>10<\/code>\uff1a\u901f\u7387 10 Mb\/s<\/li>\n\n\n\n<li><code>Base<\/code>\uff1a\u57fa\u5e26\u4f20\u8f93<\/li>\n\n\n\n<li><code>5<\/code>\uff1a\u6700\u5927\u7f51\u6bb5\u957f\u5ea6\u7ea6 500 m<\/li>\n<\/ul>\n\n\n\n<p>\u7c7b\u4f3c\u5730\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>10Base-2<\/code>\uff1a10 Mb\/s\uff0c\u57fa\u5e26\uff0c\u7ea6 200 m<\/li>\n\n\n\n<li><code>10Base-T<\/code>\uff1a10 Mb\/s\uff0c\u57fa\u5e26\uff0c\u53cc\u7ede\u7ebf Twisted Pair<\/li>\n\n\n\n<li><code>10Base-F<\/code>\uff1a10 Mb\/s\uff0c\u57fa\u5e26\uff0c\u5149\u7ea4 Fiber<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e00\u4e2a\u5f88\u597d\u8bb0\u7684\u53e3\u8bc0<\/h3>\n\n\n\n<p>\u201c\u524d\u9762\u770b\u901f\u5ea6\uff0c\u4e2d\u95f4\u770b\u9891\u5e26\uff0c\u540e\u9762\u770b\u8ddd\u79bb\u6216\u4ecb\u8d28\u3002\u201d<\/p>\n\n\n\n<p>\u4e5f\u53ef\u4ee5\u538b\u7f29\u6210\uff1a<\/p>\n\n\n\n<p>\u201c10 \u662f\u901f\u7387\uff0cBase \u662f\u57fa\u5e26\uff0c\u6570\u5b57\u591a\u534a\u8868\u8ddd\u79bb\uff0c\u5b57\u6bcd\u591a\u534a\u8868\u4ecb\u8d28\u3002\u201d<\/p>\n\n\n\n<p>\u8fd9\u91cc\u6700\u5bb9\u6613\u9519\u7684\u662f\u540e\u534a\u6bb5\u4e0d\u662f\u6c38\u8fdc\u8868\u793a\u8ddd\u79bb\u3002<br>\u50cf <code>T<\/code>\u3001<code>F<\/code> \u8fd9\u79cd\u5b57\u6bcd\u5c31\u8868\u793a\u4ecb\u8d28\u7c7b\u578b\uff0c\u4e0d\u518d\u8868\u793a\u8ddd\u79bb\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4ee5\u592a\u7f51\u7684 MAC \u5730\u5740\uff1a\u8fd9\u4e00\u5757\u600e\u4e48\u8003<\/h2>\n\n\n\n<p>MAC \u5730\u5740\u662f\u6570\u636e\u94fe\u8def\u5c42\u6700\u7a33\u5b9a\u7684\u57fa\u7840\u8003\u70b9\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u57fa\u672c\u5b9a\u4e49<\/h3>\n\n\n\n<p>MAC \u5730\u5740\u662f\u7f51\u5361\u7684\u786c\u4ef6\u5730\u5740\uff0c\u957f\u5ea6\u4e3a 48 \u4f4d\uff0c\u4e5f\u5c31\u662f 6 \u5b57\u8282\u3002<br>\u901a\u5e38\u5199\u6210 6 \u7ec4\u5341\u516d\u8fdb\u5236\u6570\uff0c\u4f8b\u5982\uff1a<\/p>\n\n\n\n<p><code>00-1A-2B-3C-4D-5E<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u7ed3\u6784<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u524d 24 \u4f4d\uff1a\u5382\u5546\u6807\u8bc6\u7b26 OUI<\/li>\n\n\n\n<li>\u540e 24 \u4f4d\uff1a\u5382\u5546\u81ea\u884c\u5206\u914d<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">3. \u5e38\u8003\u70b9<\/h3>\n\n\n\n<p>\u7b2c\u4e00\uff0cMAC \u5730\u5740\u5de5\u4f5c\u5728\u6570\u636e\u94fe\u8def\u5c42\u3002<br>\u7b2c\u4e8c\uff0c\u7f51\u5361\u7684\u4e3b\u8981\u529f\u80fd\u6a2a\u8de8<strong>\u7269\u7406\u5c42\u548c\u6570\u636e\u94fe\u8def\u5c42<\/strong>\u3002\u8fd9\u4e2a\u5224\u65ad\u9898\u662f\u5bf9\u7684\u3002\u56e0\u4e3a\u7f51\u5361\u65e2\u8981\u5b8c\u6210\u7535\/\u5149\u4fe1\u53f7\u76f8\u5173\u5904\u7406\uff0c\u4e5f\u8981\u5b8c\u6210\u6210\u5e27\u3001\u5730\u5740\u8bc6\u522b\u3001\u5dee\u9519\u68c0\u6d4b\u7b49\u94fe\u8def\u5c42\u529f\u80fd\u3002<br>\u7b2c\u4e09\uff0cMAC \u5730\u5740\u662f\u201c\u5e73\u9762\u5730\u5740\u201d\uff0c\u4e0e IP \u5730\u5740\u4e0d\u540c\uff0c\u5b83\u4e0d\u4f53\u73b0\u7f51\u7edc\u5c42\u6b21\u7ed3\u6784\u3002<br>\u7b2c\u56db\uff0c\u5e7f\u64ad\u5730\u5740\u662f\u5168 1\uff0c\u5373 <code>FF-FF-FF-FF-FF-FF<\/code>\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">CSMA\/CD\uff1a\u6574\u7ae0\u6700\u6838\u5fc3\u7684\u4e00\u5757<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u516b\u4e2a\u5b57\u8bb0\u4f4f\u6838\u5fc3\u6d41\u7a0b<\/h3>\n\n\n\n<p>\u201c\u5148\u542c\u540e\u53d1\uff0c\u8fb9\u542c\u8fb9\u53d1\uff0c\u51b2\u7a81\u505c\u53d1\uff0c\u968f\u673a\u91cd\u53d1\u201d<\/p>\n\n\n\n<p>\u8fd9\u516b\u4e2a\u5b57\u57fa\u672c\u5c31\u662f\u6240\u6709\u9009\u62e9\u9898\u548c\u5224\u65ad\u9898\u7684\u51fa\u53d1\u70b9\u3002<\/p>\n\n\n\n<p>\u5177\u4f53\u542b\u4e49\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5148\u542c\u540e\u53d1\uff1a\u53d1\u9001\u524d\u5148\u76d1\u542c\u4fe1\u9053<\/li>\n\n\n\n<li>\u8fb9\u542c\u8fb9\u53d1\uff1a\u53d1\u9001\u8fc7\u7a0b\u4e2d\u7ee7\u7eed\u76d1\u542c<\/li>\n\n\n\n<li>\u51b2\u7a81\u505c\u53d1\uff1a\u68c0\u6d4b\u5230\u51b2\u7a81\u7acb\u523b\u505c\u6b62\u53d1\u9001<\/li>\n\n\n\n<li>\u968f\u673a\u91cd\u53d1\uff1a\u7b49\u5f85\u968f\u673a\u9000\u907f\u65f6\u95f4\u540e\u518d\u91cd\u4f20<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u5b83\u9002\u7528\u4e8e\u4ec0\u4e48\u73af\u5883<\/h3>\n\n\n\n<p>CSMA\/CD \u9002\u7528\u4e8e<strong>\u6709\u7ebf\u5171\u4eab\u4ecb\u8d28\u3001\u534a\u53cc\u5de5<\/strong>\u7684\u4ee5\u592a\u7f51\u3002<\/p>\n\n\n\n<p>\u8fd9\u53e5\u8bdd\u975e\u5e38\u91cd\u8981\uff0c\u56e0\u4e3a\u5b83\u76f4\u63a5\u51b3\u5b9a\u4e86\u4e24\u4e2a\u9ad8\u9891\u5224\u65ad\u9898\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5728\u4f7f\u7528 CSMA\/CD \u7684\u4ee5\u592a\u7f51\u4e2d\uff0c\u7ad9\u70b9\u80fd\u5426\u5168\u53cc\u5de5\u901a\u4fe1\uff1f\u4e0d\u80fd<\/li>\n\n\n\n<li>\u80fd\u5426\u534a\u53cc\u5de5\u901a\u4fe1\uff1f\u53ef\u4ee5<\/li>\n<\/ul>\n\n\n\n<p>\u66f4\u51c6\u786e\u5730\u8bf4\uff0c<strong>CSMA\/CD \u53ea\u5b58\u5728\u4e8e\u534a\u53cc\u5de5\u5171\u4eab\u5f0f\u4ee5\u592a\u7f51\u4e2d<\/strong>\u3002<br>\u4e00\u65e6\u662f\u5168\u53cc\u5de5\u4ea4\u6362\u5f0f\u4ee5\u592a\u7f51\uff0c\u5c31\u6ca1\u6709\u51b2\u7a81\uff0c\u4e5f\u5c31\u4e0d\u9700\u8981 CSMA\/CD\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u6700\u77ed\u5e27\u957f\u4e3a\u4ec0\u4e48\u8981\u7b97<\/h2>\n\n\n\n<p>\u8fd9\u90e8\u5206\u662f\u8ba1\u7b97\u9898\u9ad8\u53d1\u533a\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u539f\u7406<\/h3>\n\n\n\n<p>\u4e3a\u4e86\u4fdd\u8bc1\u201c\u53d1\u9001\u65b9\u5728\u81ea\u5df1\u8fd8\u6ca1\u53d1\u5b8c\u65f6\uff0c\u5c31\u80fd\u53d1\u73b0\u6700\u8fdc\u5904\u53d1\u751f\u7684\u51b2\u7a81\u201d\uff0c\u5fc5\u987b\u6ee1\u8db3\uff1a<\/p>\n\n\n\n<p>\u6700\u77ed\u5e27\u7684\u53d1\u9001\u65f6\u5ef6 \u2265 \u4fe1\u53f7\u5728\u7f51\u7edc\u4e2d\u5f80\u8fd4\u4e00\u6b21\u7684\u4f20\u64ad\u65f6\u5ef6<\/p>\n\n\n\n<p>\u5199\u6210\u5f0f\u5b50\u5c31\u662f\uff1a<\/p>\n\n\n\n<p><code>\u6700\u77ed\u5e27\u957f \/ \u6570\u636e\u7387 \u2265 2\u03c4<\/code><\/p>\n\n\n\n<p>\u5176\u4e2d <code>\u03c4<\/code> \u662f\u7aef\u5230\u7aef\u5355\u7a0b\u4f20\u64ad\u65f6\u5ef6\u3002<\/p>\n\n\n\n<p>\u4e8e\u662f\u6709\uff1a<\/p>\n\n\n\n<p><code>\u6700\u77ed\u5e27\u957f = 2\u03c4 \u00d7 \u6570\u636e\u4f20\u8f93\u901f\u7387<\/code><\/p>\n\n\n\n<p>\u8fd9\u5c31\u662f\u6240\u6709\u6700\u77ed\u5e27\u957f\u3001\u6700\u5927\u8ddd\u79bb\u3001\u6700\u5c0f\u53d1\u9001\u957f\u5ea6\u9898\u7684\u603b\u516c\u5f0f\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u6807\u51c6\u4ee5\u592a\u7f51\u7684\u6700\u77ed\u5e27\u957f<\/h3>\n\n\n\n<p>\u7ecf\u5178\u4ee5\u592a\u7f51\u89c4\u5b9a\u6700\u77ed\u5e27\u957f\u662f <strong>64B<\/strong>\uff0c\u4e5f\u5c31\u662f <strong>512 bit<\/strong>\u3002<br>\u8fd9\u91cc\u7684 64B \u6307\u7684\u662f\u4ece\u76ee\u7684\u5730\u5740\u5b57\u6bb5\u5f00\u59cb\u5230 FCS \u7ed3\u675f\uff0c\u4e0d\u5305\u542b\u524d\u5bfc\u7801\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. \u4e3a\u4ec0\u4e48\u4f1a\u6709\u5e27\u586b\u5145<\/h3>\n\n\n\n<p>\u5982\u679c\u4e0a\u5c42\u771f\u6b63\u4ea4\u7ed9 MAC \u7684\u6570\u636e\u592a\u77ed\uff0c\u4e0d\u8db3\u4ee5\u8ba9\u6574\u4e2a\u5e27\u8fbe\u5230 64B\uff0c\u5c31\u5fc5\u987b\u5728\u6570\u636e\u5b57\u6bb5\u540e\u9762\u8865\u4e00\u4e9b\u586b\u5145\u5b57\u8282\uff0c\u8ba9\u5e27\u957f\u8fbe\u5230\u6700\u5c0f\u503c\u3002<\/p>\n\n\n\n<p>\u4ee5\u592a\u7f51\u6570\u636e\u5b57\u6bb5\u8303\u56f4\u662f 46B \u5230 1500B\u3002<br>\u6240\u4ee5\u5f53\u6570\u636e\u5b57\u6bb5\u5c0f\u4e8e 46B \u65f6\uff0c\u8981\u586b\u5145\u5230 46B\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. \u586b\u5145\u548c FCS \u7684\u5173\u7cfb<\/h3>\n\n\n\n<p>\u586b\u5145\u5b57\u8282\u662f\u4e3a\u4e86\u6ee1\u8db3<strong>\u6700\u5c0f\u5e27\u957f\u8981\u6c42<\/strong>\uff0c\u672c\u8d28\u4e0a\u662f MAC \u5c42\u7684\u9644\u52a0\u5185\u5bb9\u3002<br>\u63a5\u6536\u65b9\u6536\u5230\u5e27\u540e\uff0c\u4f1a\u5148\u8fdb\u884c FCS \u68c0\u6d4b\uff1b\u82e5 FCS \u6b63\u786e\uff0c\u518d\u6839\u636e\u957f\u5ea6\u7b49\u4fe1\u606f\u628a\u771f\u6b63\u7684\u6570\u636e\u4ea4\u7ed9\u4e0a\u5c42\uff0c\u586b\u5145\u90e8\u5206\u4e0d\u4f1a\u4f5c\u4e3a\u6709\u6548\u4e0a\u5c42\u6570\u636e\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u70b9\u5f88\u5bb9\u6613\u51fa\u5224\u65ad\u9898\uff1a<br>\u201c\u6700\u5c0f\u5e27\u957f\u4e0d\u8db3\u65f6\uff0c\u4ee5\u592a\u7f51\u901a\u8fc7\u586b\u5145\u89e3\u51b3\u3002\u201d\u5bf9\u3002<br>\u201c\u586b\u5145\u540e\u6709\u6548\u8f7d\u8377\u5c31\u53d8\u5927\u4e86\u3002\u201d\u9519\u3002\u6709\u6548\u6570\u636e\u6ca1\u6709\u53d8\uff0c\u53ea\u662f MAC \u5c42\u8865\u9f50\u4e86\u5e27\u957f\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e8c\u8fdb\u5236\u6307\u6570\u9000\u907f\u7b97\u6cd5\uff1a\u600e\u4e48\u7b97\uff0c\u600e\u4e48\u80cc<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u6838\u5fc3\u673a\u5236<\/h3>\n\n\n\n<p>\u53d1\u751f\u51b2\u7a81\u540e\uff0c\u4e0d\u662f\u7acb\u523b\u91cd\u53d1\uff0c\u800c\u662f\u968f\u673a\u7b49\u4e00\u6bb5\u65f6\u95f4\u3002<\/p>\n\n\n\n<p>\u8bbe\u53d1\u751f\u4e86\u7b2c <code>i<\/code> \u6b21\u51b2\u7a81\uff0c\u5219\uff1a<\/p>\n\n\n\n<p><code>r<\/code> \u4ece <code>{0, 1, ..., 2^k - 1}<\/code> \u4e2d\u968f\u673a\u53d6<br>\u5176\u4e2d <code>k = min(i, 10)<\/code><\/p>\n\n\n\n<p>\u7b49\u5f85\u65f6\u95f4\u4e3a\uff1a<\/p>\n\n\n\n<p><code>\u9000\u907f\u65f6\u95f4 = r \u00d7 \u4e89\u7528\u671f<\/code><\/p>\n\n\n\n<p>\u800c\u6807\u51c6\u4ee5\u592a\u7f51\u7684\u4e89\u7528\u671f\u5c31\u662f <strong>512 bit \u65f6\u95f4<\/strong>\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u4e00\u53e5\u8bdd\u8bb0\u5fc6<\/h3>\n\n\n\n<p>\u201c\u524d 10 \u6b21\u6307\u6570\u7ffb\u500d\uff0c\u4e4b\u540e\u5c01\u9876 1023\uff1b\u8fde\u7eed 16 \u6b21\u51b2\u7a81\uff0c\u76f4\u63a5\u4e22\u5f03\u3002\u201d<\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7b2c 1 \u6b21\u51b2\u7a81\uff1a<code>r \u2208 {0,1}<\/code><\/li>\n\n\n\n<li>\u7b2c 2 \u6b21\u51b2\u7a81\uff1a<code>r \u2208 {0,1,2,3}<\/code><\/li>\n\n\n\n<li>&#8230;<\/li>\n\n\n\n<li>\u7b2c 10 \u6b21\u53ca\u4ee5\u540e\uff1a\u6700\u5927\u90fd\u6309 <code>1023<\/code> \u4e2a\u4e89\u7528\u671f\u6765\u7b97<\/li>\n\n\n\n<li>\u8fde\u7eed 16 \u6b21\u51b2\u7a81\uff1a\u53d1\u9001\u5931\u8d25\uff0c\u4e22\u5f03\u8be5\u5e27<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">3. \u4e89\u7528\u671f\u600e\u4e48\u6362\u6210\u65f6\u95f4<\/h3>\n\n\n\n<p><code>\u4e89\u7528\u671f = 512 bit \u65f6\u95f4 = 512 \/ \u6570\u636e\u7387<\/code><\/p>\n\n\n\n<p>\u4f8b\u5982\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>10 Mb\/s\uff1a<code>512 \/ 10^7 = 51.2 \u03bcs<\/code><\/li>\n\n\n\n<li>100 Mb\/s\uff1a<code>512 \/ 10^8 = 5.12 \u03bcs<\/code><\/li>\n\n\n\n<li>1 Gb\/s\uff1a<code>512 \/ 10^9 = 0.512 \u03bcs<\/code><\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u9ad8\u901f\u4ee5\u592a\u7f51\uff1a100M\u30011G\u300110G \u600e\u4e48\u8003<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u5feb\u901f\u4ee5\u592a\u7f51\uff08100 Mb\/s\uff09<\/h3>\n\n\n\n<p>\u6838\u5fc3\u601d\u8def\u662f\uff1a<strong>\u901f\u5ea6\u63d0\u9ad8\uff0c\u4f46\u5e27\u683c\u5f0f\u57fa\u672c\u4e0d\u53d8<\/strong>\u3002<br>\u4ecd\u7136\u4fdd\u7559\u4ee5\u592a\u7f51 MAC \u673a\u5236\uff0c\u6700\u5c0f\u5e27\u957f\u4ecd\u6309 64B \u8fd9\u4e2a\u6846\u67b6\u6765\u7406\u89e3\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u5409\u6bd4\u7279\u4ee5\u592a\u7f51\uff081 Gb\/s\uff09<\/h3>\n\n\n\n<p>\u8003\u8bd5\u91cc\u8981\u8bb0\u4f4f\u4e24\u4ef6\u4e8b\uff1a<\/p>\n\n\n\n<p>\u7b2c\u4e00\uff0c\u5409\u6bd4\u7279\u4ee5\u592a\u7f51\u65e2\u53ef\u4ee5\u534a\u53cc\u5de5\uff0c\u4e5f\u53ef\u4ee5\u5168\u53cc\u5de5\u3002<br>\u7b2c\u4e8c\uff0c\u534a\u53cc\u5de5\u65f6\u82e5\u4ecd\u4f7f\u7528 CSMA\/CD\uff0c\u4f1a\u9047\u5230\u201c\u4f20\u64ad\u65f6\u5ef6\u76f8\u5bf9\u8fc7\u5927\u201d\u7684\u95ee\u9898\uff0c\u56e0\u6b64\u6807\u51c6\u4e2d\u5f15\u5165\u4e86<strong>\u8f7d\u6ce2\u6269\u5c55<\/strong>\u3001<strong>\u5e27\u7a81\u53d1<\/strong>\u7b49\u673a\u5236\u6765\u9002\u914d\u3002<\/p>\n\n\n\n<p>\u4f46\u4ece\u73b0\u5728\u505a\u9898\u548c\u5b9e\u9645\u7f51\u7edc\u89d2\u5ea6\uff0c\u770b\u5230\u5343\u5146\u4ee5\u592a\u7f51\uff0c\u901a\u5e38\u9ed8\u8ba4\u662f<strong>\u4ea4\u6362\u5f0f\u5168\u53cc\u5de5<\/strong>\uff0c\u57fa\u672c\u4e0d\u518d\u7528 CSMA\/CD\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. \u5341\u5409\u6bd4\u7279\u4ee5\u592a\u7f51\uff0810 Gb\/s\uff09<\/h3>\n\n\n\n<p>\u8fd9\u4e2a\u7279\u522b\u5bb9\u6613\u8003\uff1a<\/p>\n\n\n\n<p><strong>\u5341\u5409\u6bd4\u7279\u4ee5\u592a\u7f51\u53ea\u5de5\u4f5c\u5728\u5168\u53cc\u5de5\u65b9\u5f0f\u4e0b\uff0c\u4e0d\u518d\u4f7f\u7528 CSMA\/CD\u3002<\/strong><\/p>\n\n\n\n<p>\u8fd9\u662f\u4e2a\u5f88\u7a33\u7684\u5224\u65ad\u70b9\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u5149\u7ea4\u4ee5\u592a\u7f51\u80fd\u4e0d\u80fd\u4f7f\u7528 CSMA\/CD<\/h2>\n\n\n\n<p>\u8fd9\u9898\u5bb9\u6613\u51fa\u201c\u5bf9\u8fd8\u662f\u9519\u201d\uff0c\u4f46\u5b83\u5176\u5b9e\u5e26\u4e00\u70b9\u8bed\u5883\u3002<\/p>\n\n\n\n<p>\u66f4\u7a33\u59a5\u7684\u7b54\u6cd5\u662f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4ece\u73b0\u4ee3\u4e3b\u6d41\u5e94\u7528\u770b\uff0c\u5149\u7ea4\u4ee5\u592a\u7f51\u901a\u5e38\u5de5\u4f5c\u5728\u4ea4\u6362\u5f0f\u5168\u53cc\u5de5\u65b9\u5f0f\u4e0b\uff0c<strong>\u4e00\u822c\u4e0d\u4f7f\u7528 CSMA\/CD<\/strong><\/li>\n\n\n\n<li>\u4ece\u6807\u51c6\u548c\u5386\u53f2\u5b9e\u73b0\u89d2\u5ea6\uff0c\u90e8\u5206\u5171\u4eab\u5f0f\u3001\u534a\u53cc\u5de5\u5149\u7ea4\u4ee5\u592a\u7f51\u66fe\u53ef\u4ee5\u914d\u5408 CSMA\/CD \u4f7f\u7528<\/li>\n<\/ul>\n\n\n\n<p>\u6240\u4ee5\u5982\u679c\u9898\u76ee\u6ca1\u6709\u7279\u522b\u5f3a\u8c03\u201c\u73b0\u4ee3\u4ea4\u6362\u5f0f\u5168\u53cc\u5de5\u201d\uff0c\u800c\u662f\u7b3c\u7edf\u95ee\u201c\u5149\u7ea4\u4ee5\u592a\u7f51\u4e5f\u53ef\u4ee5\u4f7f\u7528 CSMA\/CD \u5417\u201d\uff0c\u6700\u597d\u7ed3\u5408\u6559\u6750\u8bed\u5883\u3002<br>\u6309\u8003\u7814\u5e38\u89c1\u53e3\u5f84\uff0c\u901a\u5e38\u66f4\u503e\u5411\u4e8e\u7b54\uff1a<strong>\u73b0\u4ee3\u5149\u7ea4\u4ee5\u592a\u7f51\u901a\u5e38\u4e0d\u4f7f\u7528 CSMA\/CD<\/strong>\u3002<br>\u4f46\u82e5\u9898\u76ee\u5f3a\u8c03\u201c\u534a\u53cc\u5de5\u5171\u4eab\u4ecb\u8d28\u201d\uff0c\u5219\u4e0d\u80fd\u7edd\u5bf9\u8bf4\u201c\u4e0d\u53ef\u80fd\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">CSMA\/CA\uff1a\u65e0\u7ebf\u5c40\u57df\u7f51\u4e3a\u4ec0\u4e48\u4e0d\u7528 CD\uff0c\u800c\u8981\u7528 CA<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u4e3a\u4ec0\u4e48\u65e0\u7ebf\u5c40\u57df\u7f51\u4e0d\u7528 CSMA\/CD<\/h3>\n\n\n\n<p>\u6839\u672c\u539f\u56e0\u662f\uff1a<strong>\u65e0\u7ebf\u73af\u5883\u91cc\u5f88\u96be\u4e00\u8fb9\u53d1\u4e00\u8fb9\u53ef\u9760\u5730\u68c0\u6d4b\u78b0\u649e<\/strong>\u3002<\/p>\n\n\n\n<p>\u539f\u56e0\u53ef\u4ee5\u4ece\u4e09\u4e2a\u89d2\u5ea6\u8bb0\uff1a<\/p>\n\n\n\n<p>\u7b2c\u4e00\uff0c\u53d1\u9001\u65f6\u672c\u673a\u53d1\u51fa\u7684\u4fe1\u53f7\u592a\u5f3a\uff0c\u4f1a\u6df9\u6ca1\u522b\u4eba\u53d1\u6765\u7684\u5f31\u4fe1\u53f7\uff0c\u4e0d\u5bb9\u6613\u5728\u53d1\u9001\u540c\u65f6\u51c6\u786e\u68c0\u6d4b\u51b2\u7a81\u3002<br>\u7b2c\u4e8c\uff0c\u65e0\u7ebf\u6709\u9690\u85cf\u7ad9\u95ee\u9898\u3002A \u548c C \u90fd\u53ef\u80fd\u542c\u4e0d\u5230\u5f7c\u6b64\uff0c\u4f46\u90fd\u80fd\u7ed9 B \u53d1\uff0c\u5bfc\u81f4\u51b2\u7a81\u3002<br>\u7b2c\u4e09\uff0c\u65e0\u7ebf\u4f20\u64ad\u73af\u5883\u590d\u6742\uff0c\u78b0\u649e\u68c0\u6d4b\u4ee3\u4ef7\u9ad8\u3001\u6548\u679c\u5dee\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u65e0\u7ebf\u5c40\u57df\u7f51\u4e0d\u505a\u201c\u78b0\u649e\u68c0\u6d4b\u201d\uff0c\u6539\u505a\u201c\u78b0\u649e\u907f\u514d\u201d\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. CSMA\/CA \u7684\u4e3b\u8981\u7279\u70b9<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u53d1\u9001\u524d\u5148\u76d1\u542c\u4fe1\u9053<\/li>\n\n\n\n<li>\u4fe1\u9053\u7a7a\u95f2\u540e\uff0c\u4e0d\u662f\u7acb\u523b\u53d1\u9001\uff0c\u800c\u662f\u5148\u7b49\u5f85\u4e00\u6bb5\u5e27\u95f4\u95f4\u9694<\/li>\n\n\n\n<li>\u518d\u6267\u884c\u968f\u673a\u9000\u907f<\/li>\n\n\n\n<li>\u53d1\u9001\u540e\u9760\u63a5\u6536\u65b9\u8fd4\u56de ACK \u786e\u8ba4<\/li>\n\n\n\n<li>\u5fc5\u8981\u65f6\u4f7f\u7528 RTS\/CTS \u8fdb\u4e00\u6b65\u51cf\u5c11\u51b2\u7a81<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u91cc\u6700\u5bb9\u6613\u9519\u7684\u5730\u65b9\u662f\uff1a<\/p>\n\n\n\n<p><strong>CSMA\/CA \u4e0d\u662f\u4fdd\u8bc1\u7edd\u5bf9\u4e0d\u4f1a\u51b2\u7a81\uff0c\u800c\u662f\u5c3d\u91cf\u907f\u514d\u51b2\u7a81\u3002<\/strong><br>\u6240\u4ee5\u201cCA \u65e2\u7136\u53eb\u51b2\u7a81\u907f\u514d\uff0c\u56e0\u6b64\u4e0d\u4f1a\u51fa\u73b0\u51b2\u7a81\u201d\u662f\u9519\u7684\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u5e27\u95f4\u95f4\u9694\uff1aSIFS\u3001PIFS\u3001DIFS \u7684\u5173\u7cfb\u548c\u4f5c\u7528<\/h2>\n\n\n\n<p>\u65e0\u7ebf\u5c40\u57df\u7f51\u91cc\u4e0d\u540c\u4f18\u5148\u7ea7\u7684\u53d1\u9001\uff0c\u9700\u8981\u9760\u4e0d\u540c\u957f\u5ea6\u7684\u5e27\u95f4\u95f4\u9694\u6765\u533a\u5206\u3002<\/p>\n\n\n\n<p>\u957f\u5ea6\u5173\u7cfb\u4e00\u5b9a\u8981\u80cc\u4f4f\uff1a<\/p>\n\n\n\n<p><code>SIFS &lt; PIFS &lt; DIFS<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u542b\u4e49<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>SIFS<\/code>\uff1a\u6700\u77ed\uff0c\u7528\u4e8e ACK\u3001CTS\u3001\u5206\u7247\u95f4\u54cd\u5e94\u7b49\uff0c\u4f18\u5148\u7ea7\u6700\u9ad8<\/li>\n\n\n\n<li><code>PIFS<\/code>\uff1a\u70b9\u534f\u8c03\u529f\u80fd\u4f7f\u7528<\/li>\n\n\n\n<li><code>DIFS<\/code>\uff1a\u5206\u5e03\u5f0f\u534f\u8c03\u529f\u80fd\u4e0b\uff0c\u666e\u901a\u7ad9\u70b9\u7ade\u4e89\u53d1\u9001\u524d\u7b49\u5f85\u7684\u65f6\u95f4<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e00\u4e2a\u8bb0\u6cd5<\/h3>\n\n\n\n<p>\u201cS \u6700\u77ed\uff0cP \u5c45\u4e2d\uff0cD \u6700\u957f\uff1b\u54cd\u5e94\u4f18\u5148\u4e8e\u534f\u8c03\uff0c\u534f\u8c03\u4f18\u5148\u4e8e\u666e\u901a\u53d1\u9001\u3002\u201d<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u201c\u63a8\u8fdf\u201d\u4e0e\u201c\u9000\u907f\u201d\u7684\u533a\u522b<\/h2>\n\n\n\n<p>\u8fd9\u7c7b\u9898\u76ee\u63aa\u8f9e\u6709\u65f6\u4e0d\u7edf\u4e00\uff0c\u4f46\u672c\u8d28\u662f\u5728\u533a\u5206\u4e24\u79cd\u7b49\u5f85\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u63a8\u8fdf\uff08defer\uff09<\/h3>\n\n\n\n<p>\u5f53\u7ad9\u70b9\u53d1\u73b0\u4fe1\u9053\u5fd9\uff0c\u6216\u8005\u8fd8\u6ca1\u6ee1\u8db3\u6700\u57fa\u672c\u7684\u5e27\u95f4\u95f4\u9694\u6761\u4ef6\u65f6\uff0c\u5b83\u53ea\u80fd\u5148\u7b49\uff0c\u8fd9\u79cd\u7b49\u662f\u201c\u88ab\u52a8\u7b49\u5f85\u201d\uff0c\u8fd8\u6ca1\u6709\u8fdb\u5165\u968f\u673a\u7ade\u4e89\u9636\u6bb5\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u9000\u907f\uff08backoff\uff09<\/h3>\n\n\n\n<p>\u5f53\u4fe1\u9053\u7a7a\u95f2\u5e76\u6ee1\u8db3 DIFS \u540e\uff0c\u7ad9\u70b9\u8fd8\u8981\u968f\u673a\u9009\u4e00\u4e2a\u9000\u907f\u8ba1\u65f6\u5668\uff0c\u6309\u65f6\u9699\u5012\u8ba1\u65f6\uff1b\u5982\u679c\u4e2d\u9014\u4fe1\u9053\u53c8\u5fd9\uff0c\u8ba1\u65f6\u5668\u51bb\u7ed3\uff0c\u5f85\u4fe1\u9053\u518d\u6b21\u7a7a\u95f2\u5e76\u7ecf\u8fc7 DIFS \u540e\u7ee7\u7eed\u5012\u8ba1\u65f6\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u533a\u522b\u53ef\u4ee5\u6982\u62ec\u4e3a\uff1a<\/p>\n\n\n\n<p>\u63a8\u8fdf\u662f\u201c\u5148\u522b\u53d1\uff0c\u6761\u4ef6\u8fd8\u6ca1\u5230\u201d\uff1b<br>\u9000\u907f\u662f\u201c\u6761\u4ef6\u5230\u4e86\uff0c\u4f46\u4e3a\u4e86\u51cf\u5c11\u51b2\u7a81\uff0c\u8fd8\u8981\u968f\u673a\u7b49\u4e00\u6bb5\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">802.11 \u4e2d\u5730\u5740\u5b57\u6bb5\u7684\u542b\u4e49\u53d6\u51b3\u4e8e\u4ec0\u4e48<\/h2>\n\n\n\n<p>\u4f60\u9898\u76ee\u91cc\u5199\u6210\u4e86\u201c802.1\u201d\uff0c\u8fd9\u91cc\u5927\u6982\u7387\u662f <strong>802.11<\/strong>\u3002<\/p>\n\n\n\n<p>\u5728 802.11 MAC \u5e27\u4e2d\uff0c\u5730\u5740\u5b57\u6bb5\u7684\u5177\u4f53\u542b\u4e49\u53d6\u51b3\u4e8e\u63a7\u5236\u5b57\u6bb5\u4e2d\u7684\uff1a<\/p>\n\n\n\n<p><code>To DS<\/code> \u548c <code>From DS<\/code><\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u201c\u662f\u5426\u53d1\u5f80\u5206\u5e03\u7cfb\u7edf\u201d\u201c\u662f\u5426\u6765\u81ea\u5206\u5e03\u7cfb\u7edf\u201d\u8fd9\u4e24\u4e2a\u6807\u5fd7\u4f4d\u3002<br>\u56e0\u6b64\u540c\u6837\u662f\u5730\u5740 1\u3001\u5730\u5740 2\u3001\u5730\u5740 3\uff0c\u5728\u4e0d\u540c\u60c5\u51b5\u4e0b\u542b\u4e49\u53ef\u80fd\u5206\u522b\u662f\u63a5\u6536\u5730\u5740\u3001\u53d1\u9001\u5730\u5740\u3001\u76ee\u7684\u5730\u5740\u3001\u6e90\u5730\u5740\u3001BSSID \u7b49\u3002<\/p>\n\n\n\n<p>\u8fd9\u662f\u4e2a\u975e\u5e38\u5178\u578b\u7684\u9009\u62e9\u9898\u70b9\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">VLAN\uff1a\u8fd9\u5757\u8981\u6293\u4ec0\u4e48<\/h2>\n\n\n\n<p>VLAN \u672c\u8d28\u4e0a\u662f<strong>\u628a\u4e00\u4e2a\u7269\u7406\u5c40\u57df\u7f51\u5212\u5206\u6210\u591a\u4e2a\u903b\u8f91\u5c40\u57df\u7f51<\/strong>\u3002<br>\u6700\u6838\u5fc3\u7684\u6548\u679c\u5c31\u662f\uff1a<strong>\u5212\u5206\u5e7f\u64ad\u57df<\/strong>\u3002<\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0c\u4ea4\u6362\u673a\u867d\u7136\u80fd\u9694\u79bb\u51b2\u7a81\u57df\uff0c\u4f46\u9ed8\u8ba4\u4e0d\u80fd\u9694\u79bb\u5e7f\u64ad\u57df\uff1b\u914d\u7f6e VLAN \u540e\uff0c\u5e7f\u64ad\u57df\u4e5f\u88ab\u8fdb\u4e00\u6b65\u5212\u5f00\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. 802.1Q \u6807\u7b7e<\/h3>\n\n\n\n<p>802.1Q \u662f VLAN \u7684\u6807\u8bb0\u6807\u51c6\uff0c\u5b83\u4f1a\u5728\u539f\u6765\u4ee5\u592a\u7f51\u5e27\u4e2d\u63d2\u5165\u4e00\u4e2a <strong>4 \u5b57\u8282<\/strong> \u7684 VLAN \u6807\u7b7e\u3002<\/p>\n\n\n\n<p>\u63d2\u5165\u4f4d\u7f6e\u662f\uff1a<\/p>\n\n\n\n<p>\u6e90 MAC \u5730\u5740\u4e4b\u540e\uff0c\u7c7b\u578b\/\u957f\u5ea6\u5b57\u6bb5\u4e4b\u524d\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. 4 \u5b57\u8282\u6807\u7b7e\u91cc\u8003\u4ec0\u4e48<\/h3>\n\n\n\n<p>\u4e3b\u8981\u8bb0 <code>VID<\/code>\uff0c\u4e5f\u5c31\u662f VLAN ID\uff0c\u7528\u6765\u6807\u8bc6\u5e27\u5c5e\u4e8e\u54ea\u4e2a VLAN\u3002<br>\u4e25\u683c\u8bf4 4 \u5b57\u8282\u7531 TPID \u548c TCI \u7ec4\u6210\uff0cVID \u662f TCI \u91cc\u7684 12 \u4f4d\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. \u63d2\u5165\u6807\u7b7e\u540e\u6700\u5927\u5e27\u957f\u662f\u5426\u4fdd\u6301\u4e0d\u53d8<\/h3>\n\n\n\n<p>\u4e0d\u4f1a\u4fdd\u6301\u4e0d\u53d8\u3002<br>\u539f\u6807\u51c6\u4ee5\u592a\u7f51\u6700\u5927\u5e27\u957f 1518B\uff0c\u63d2\u5165 802.1Q \u6807\u7b7e\u540e\u53ef\u4ee5\u5230 <strong>1522B<\/strong>\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u9898\u76ee\u91cc\u201c\u63d2\u5165 VLAN \u6807\u7b7e\u540e\uff0c\u4ee5\u592a\u7f51\u6700\u5927\u5e27\u957f\u4e5f\u9700\u8981\u4fdd\u6301\u4e0d\u53d8\u201d\u662f\u9519\u7684\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. \u914d\u4e86 VLAN\uff0c\u4e24\u53f0\u4e3b\u673a\u901a\u4fe1\u4e00\u5b9a\u7528 802.1Q \u5e27\u5417<\/h3>\n\n\n\n<p>\u4e0d\u4e00\u5b9a\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u4e3b\u673a\u63a5\u5728\u4ea4\u6362\u673a\u7684 <strong>access \u7aef\u53e3<\/strong>\uff0c\u4e3b\u673a\u6536\u5230\u548c\u53d1\u51fa\u7684\u901a\u5e38\u8fd8\u662f\u666e\u901a\u4ee5\u592a\u7f51\u5e27\uff1b<br>\u4ea4\u6362\u673a\u4e4b\u95f4\u7684 <strong>trunk \u94fe\u8def<\/strong> \u624d\u5e38\u5e38\u643a\u5e26 802.1Q \u6807\u7b7e\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e5f\u662f\u5f88\u5e38\u89c1\u7684\u5224\u65ad\u70b9\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u9ad8\u9891\u5224\u65ad\u9898\u4e0e\u9009\u62e9\u9898\uff0c\u4e00\u6b21\u6027\u7406\u987a<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. \u5c31\u4ea4\u6362\u6280\u672f\u800c\u8a00\uff0c\u4ee5\u592a\u7f51\u91c7\u7528\u4ec0\u4e48\u6280\u672f<\/h3>\n\n\n\n<p>\u5e38\u89c1\u7b54\u6cd5\uff1a<strong>\u5e7f\u64ad\u5f0f\u901a\u4fe1\u6280\u672f<\/strong>\u3002<br>\u82e5\u653e\u5728\u4ea4\u6362\u65b9\u5f0f\u6bd4\u8f83\u91cc\uff0c\u4e5f\u5c5e\u4e8e<strong>\u5206\u7ec4\u4ea4\u6362<\/strong>\u3002\u505a\u9898\u770b\u9898\u5e72\u8bbe\u95ee\u89d2\u5ea6\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. \u7f51\u5361\u5b9e\u73b0\u7684\u4e3b\u8981\u529f\u80fd\u5728\u7269\u7406\u5c42\u548c\u6570\u636e\u94fe\u8def\u5c42\uff0c\u5bf9\u5417<\/h3>\n\n\n\n<p>\u5bf9\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. \u5149\u7ea4\u4ee5\u592a\u7f51\u4e5f\u53ef\u4ee5\u4f7f\u7528 CSMA\/CD \u534f\u8bae\uff0c\u5bf9\u8fd8\u662f\u9519<\/h3>\n\n\n\n<p>\u6309\u73b0\u4ee3\u4e3b\u6d41\u5e94\u7528\u8bed\u5883\uff0c\u591a\u5224<strong>\u9519<\/strong>\uff1b<br>\u82e5\u9898\u76ee\u5f3a\u8c03\u5171\u4eab\u5f0f\u534a\u53cc\u5de5\u5149\u7ea4\u4ee5\u592a\u7f51\uff0c\u5219\u4e0d\u80fd\u7edd\u5bf9\u5426\u5b9a\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. \u5728 CSMA\/CD \u4ee5\u592a\u7f51\u4e2d\uff0c\u7ad9\u70b9\u80fd\u5426\u5168\u53cc\u5de5\u901a\u4fe1<\/h3>\n\n\n\n<p>\u4e0d\u80fd\u3002CSMA\/CD \u5bf9\u5e94\u534a\u53cc\u5de5\u5171\u4eab\u4ecb\u8d28\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5. \u5728 CSMA\/CD \u4ee5\u592a\u7f51\u4e2d\uff0c\u7ad9\u70b9\u80fd\u5426\u534a\u53cc\u5de5\u901a\u4fe1<\/h3>\n\n\n\n<p>\u53ef\u4ee5\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">6. \u5bf9\u6b63\u786e\u6536\u5230\u7684\u6570\u636e\u5e27\u8fdb\u884c\u786e\u8ba4\u7684 MAC \u534f\u8bae\u662f\u4ec0\u4e48<\/h3>\n\n\n\n<p>\u65e0\u7ebf\u5c40\u57df\u7f51\u7684 <strong>CSMA\/CA<\/strong> \u901a\u8fc7 ACK \u8fdb\u884c\u786e\u8ba4\u3002<br>\u800c\u4ee5\u592a\u7f51 MAC \u672c\u8eab<strong>\u4e0d\u5bf9\u5355\u4e2a\u6b63\u786e\u6536\u5230\u7684\u6570\u636e\u5e27\u9010\u5e27\u786e\u8ba4<\/strong>\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">7. \u4ee5\u592a\u7f51 MAC \u534f\u8bae\u63d0\u4f9b\u7684\u662f\u4ec0\u4e48\u670d\u52a1<\/h3>\n\n\n\n<p><strong>\u65e0\u8fde\u63a5\u3001\u4e0d\u53ef\u9760\u7684\u5c3d\u6700\u5927\u52aa\u529b\u4ea4\u4ed8\u670d\u52a1\u3002<\/strong><\/p>\n\n\n\n<p>\u8fd9\u53e5\u8bdd\u8981\u80cc\u719f\u3002<br>\u4e0d\u786e\u8ba4\u3001\u4e0d\u91cd\u4f20\u3001\u4e0d\u4fdd\u8bc1\u6309\u5e8f\uff0c\u662f\u9ad8\u9891\u8003\u70b9\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">8. \u5173\u4e8e CSMA\/CA \u534f\u8bae\uff0c\u4e0b\u5217\u6b63\u786e\u7684\u662f\u54ea\u4e00\u9879<\/h3>\n\n\n\n<p>\u4f60\u7ed9\u7684\u51e0\u4e2a\u8bf4\u6cd5\u91cc\uff0c\u53ea\u6709\u8fd9\u4e00\u9879\u662f\u5bf9\u7684\uff1a<\/p>\n\n\n\n<p>\u201c\u63a5\u6536\u65b9\u6536\u5230\u6570\u636e\u5e27\u540e\uff0c\u9700\u8981\u5411\u53d1\u9001\u65b9\u8fd4\u56de\u786e\u8ba4\u5e27\u3002\u201d<\/p>\n\n\n\n<p>\u5176\u4f59\u51e0\u9879\u90fd\u9519\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u201c\u4e0d\u4f1a\u51fa\u73b0\u51b2\u7a81\u201d\u9519<\/li>\n\n\n\n<li>\u201c\u76d1\u542c\u5230\u7a7a\u95f2\u540e\u7acb\u5373\u53d1\u9001\u201d\u9519\uff0c\u901a\u5e38\u8981\u5148\u7b49\u5f85 DIFS\uff0c\u518d\u9000\u907f<\/li>\n\n\n\n<li>\u201c\u4e0d\u9700\u8981\u4f7f\u7528\u9000\u907f\u7b97\u6cd5\u201d\u9519\uff0cCSMA\/CA \u4ecd\u8981\u9000\u907f<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">9. \u5173\u4e8e 802.1Q \u5e27\u63cf\u8ff0\u4e2d\u9519\u8bef\u7684\u662f\u54ea\u9879<\/h3>\n\n\n\n<p>\u9519\u8bef\u9879\u662f\uff1a<\/p>\n\n\n\n<p>\u201c\u63d2\u5165 VLAN \u6807\u7b7e\u540e\uff0c\u4ee5\u592a\u7f51\u7684\u6700\u5927\u5e27\u957f\u4e5f\u9700\u8981\u4fdd\u6301\u4e0d\u53d8\u3002\u201d<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u8ba1\u7b97\u9898 1\uff1a100 Mb\/s \u4ee5\u592a\u7f51\uff0c\u7b2c\u4e8c\u6b21\u91cd\u4f20\u524d\u6700\u5927\u9000\u907f\u65f6\u95f4<\/h2>\n\n\n\n<p>\u9898\u610f\u6309\u8003\u7814\u4e60\u60ef\u7406\u89e3\u4e3a\uff1a100 Mb\/s \u4ee5\u592a\u7f51\uff0c\u67d0\u7ad9\u5df2\u53d1\u751f\u4e24\u6b21\u51b2\u7a81\uff0c\u73b0\u5728\u51c6\u5907\u8fdb\u884c\u7b2c\u4e8c\u6b21\u91cd\u4f20\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e00\u6b65\uff1a\u7b97\u4e89\u7528\u671f<\/h3>\n\n\n\n<p>100 Mb\/s \u4e0b\uff1a<\/p>\n\n\n\n<p><code>\u4e89\u7528\u671f = 512 \/ 100000000 s = 5.12 \u03bcs<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e8c\u6b65\uff1a\u7b2c\u4e8c\u6b21\u91cd\u4f20\u5bf9\u5e94\u7684\u968f\u673a\u8303\u56f4<\/h3>\n\n\n\n<p>\u82e5\u5df2\u7ecf\u7ecf\u5386\u4e24\u6b21\u51b2\u7a81\uff0c\u5219\uff1a<\/p>\n\n\n\n<p><code>r \u2208 {0,1,2,3}<\/code><\/p>\n\n\n\n<p>\u6700\u5927\u4e3a 3\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e09\u6b65\uff1a\u7b97\u6700\u5927\u9000\u907f\u65f6\u95f4<\/h3>\n\n\n\n<p><code>\u6700\u5927\u9000\u907f\u65f6\u95f4 = 3 \u00d7 5.12 \u03bcs = 15.36 \u03bcs<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7ed3\u8bba<\/h3>\n\n\n\n<p>\u6700\u5927\u9000\u907f\u65f6\u95f4\u662f <strong>15.36 \u03bcs<\/strong>\u3002<\/p>\n\n\n\n<p>\u8fd9\u91cc\u6700\u5bb9\u6613\u9519\u7684\u70b9\u662f\u628a\u201c\u7b2c\u4e8c\u6b21\u91cd\u4f20\u201d\u8bef\u770b\u6210\u201c\u7b2c\u4e00\u6b21\u51b2\u7a81\u540e\u7acb\u5373\u51c6\u5907\u91cd\u4f20\u201d\u3002<br>\u505a\u9898\u65f6\u8981\u5148\u5224\u65ad\uff1a\u9898\u76ee\u8bf4\u7684\u662f\u201c\u7b2c\u51e0\u6b21\u51b2\u7a81\u540e\u201d\uff0c\u8fd8\u662f\u201c\u7b2c\u51e0\u6b21\u91cd\u4f20\u524d\u201d\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u8ba1\u7b97\u9898 2\uff1a1 Gb\/s\uff0c\u6700\u5c0f\u6b63\u5e38\u5e27\u957f 800 bit\uff0c\u6c42\u6700\u8fdc\u7ad9\u70b9\u8ddd\u79bb<\/h2>\n\n\n\n<p>\u9898\u76ee\uff1a\u4f20\u8f93\u901f\u7387 1 Gb\/s\uff0c\u4f20\u64ad\u901f\u7387 200000 km\/s\uff0c\u6700\u5c0f\u5e27\u957f 800 bit\u3002\u95ee\u6700\u8fdc\u4e24\u4e2a\u7ad9\u70b9\u7684\u8ddd\u79bb\u6700\u591a\u662f\u591a\u5c11\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e00\u6b65\uff1a\u5957\u6700\u77ed\u5e27\u957f\u6761\u4ef6<\/h3>\n\n\n\n<p><code>\u6700\u77ed\u5e27\u53d1\u9001\u65f6\u95f4 \u2265 \u5f80\u8fd4\u4f20\u64ad\u65f6\u5ef6<\/code><\/p>\n\n\n\n<p>\u5373\uff1a<\/p>\n\n\n\n<p><code>800 \/ 10^9 \u2265 2\u03c4<\/code><\/p>\n\n\n\n<p>\u5f97\u5230\uff1a<\/p>\n\n\n\n<p><code>\u03c4 \u2264 400 ns<\/code><\/p>\n\n\n\n<p>\u8fd9\u91cc <code>\u03c4<\/code> \u662f\u5355\u7a0b\u4f20\u64ad\u65f6\u5ef6\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e8c\u6b65\uff1a\u7531\u4f20\u64ad\u65f6\u5ef6\u7b97\u8ddd\u79bb<\/h3>\n\n\n\n<p>\u4f20\u64ad\u901f\u7387\uff1a<\/p>\n\n\n\n<p><code>v = 200000 km\/s = 2 \u00d7 10^8 m\/s<\/code><\/p>\n\n\n\n<p>\u6240\u4ee5\uff1a<\/p>\n\n\n\n<p><code>d = v \u00d7 \u03c4 = 2 \u00d7 10^8 \u00d7 400 \u00d7 10^-9 = 80 m<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7ed3\u8bba<\/h3>\n\n\n\n<p>\u6700\u8fdc\u4e24\u4e2a\u7ad9\u70b9\u4e4b\u95f4\u7684\u8ddd\u79bb\u6700\u591a\u662f <strong>80 m<\/strong>\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u6613\u9519\u70b9<\/h3>\n\n\n\n<p>\u5f88\u591a\u4eba\u4f1a\u628a\u5355\u7a0b\u65f6\u5ef6\u548c\u5f80\u8fd4\u65f6\u5ef6\u6df7\u6389\uff0c\u591a\u4e58\u6216\u5c11\u4e58\u4e00\u4e2a 2\u3002<br>\u8bb0\u4f4f\u4e00\u53e5\u8bdd\u5c31\u591f\u4e86\uff1a<\/p>\n\n\n\n<p>\u201c\u6700\u77ed\u5e27\u957f\u7ea6\u675f\u7684\u662f\u5f80\u8fd4\u65f6\u95f4 2\u03c4\uff0c\u6700\u540e\u6c42\u8ddd\u79bb\u65f6\u518d\u56de\u5230\u5355\u7a0b \u03c4\u3002\u201d<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u8ba1\u7b97\u9898 3\uff1a10Base-T \u51b2\u7a81 11 \u6b21\u540e\uff0c\u4e0b\u4e00\u6b21\u5c1d\u8bd5\u524d\u6700\u5927\u7b49\u5f85\u65f6\u95f4<\/h2>\n\n\n\n<p>\u9898\u76ee\uff1a\u5728 10Base-T \u51b2\u7a81\u57df\u5185\uff0c\u8fde\u7eed\u53d1\u751f 11 \u6b21\u51b2\u7a81\uff0c\u95ee\u518d\u6b21\u5c1d\u8bd5\u53d1\u9001\u8be5\u6570\u636e\u5e27\u524d\u6700\u5927\u65f6\u95f4\u95f4\u9694\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e00\u6b65\uff1a10 Mb\/s \u4e0b\u4e89\u7528\u671f<\/h3>\n\n\n\n<p><code>512 \/ 10^7 s = 51.2 \u03bcs<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e8c\u6b65\uff1a11 \u6b21\u51b2\u7a81\u65f6\u7684\u9000\u907f\u4e0a\u9650<\/h3>\n\n\n\n<p>\u6307\u6570\u9000\u907f\u5230\u7b2c 10 \u6b21\u540e\u5c01\u9876\uff0c\u6240\u4ee5\u7b2c 11 \u6b21\u51b2\u7a81\u540e\u4ecd\u6309\uff1a<\/p>\n\n\n\n<p><code>r \u2208 {0,1,2,...,1023}<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c\u4e09\u6b65\uff1a\u6700\u5927\u7b49\u5f85\u65f6\u95f4<\/h3>\n\n\n\n<p><code>\u6700\u5927\u9000\u907f\u65f6\u95f4 = 1023 \u00d7 51.2 \u03bcs = 52377.6 \u03bcs<\/code><\/p>\n\n\n\n<p>\u4e5f\u5c31\u662f\uff1a<\/p>\n\n\n\n<p><code>52.3776 ms<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7ed3\u8bba<\/h3>\n\n\n\n<p>\u6700\u5927\u65f6\u95f4\u95f4\u9694\u662f <strong>52.3776 ms<\/strong>\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u8ba1\u7b97\u9898 4\uff1a10 Mb\/s\uff0c\u7532\u4e59\u76f8\u8ddd 2 km\uff0cCSMA\/CD \u4e24\u95ee<\/h2>\n\n\n\n<p>\u5df2\u77e5\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6570\u636e\u4f20\u8f93\u901f\u7387\uff1a10 Mb\/s<\/li>\n\n\n\n<li>\u7532\u4e59\u8ddd\u79bb\uff1a2 km<\/li>\n\n\n\n<li>\u4f20\u64ad\u901f\u7387\uff1a200000 km\/s<\/li>\n<\/ul>\n\n\n\n<p>\u5148\u7b97\u5355\u7a0b\u4f20\u64ad\u65f6\u5ef6\uff1a<\/p>\n\n\n\n<p><code>\u03c4 = 2 \/ 200000 s = 10^-5 s = 10 \u03bcs<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c 1 \u95ee\uff1a\u82e5\u53d1\u751f\u51b2\u7a81\uff0c\u4ece\u5f00\u59cb\u53d1\u9001\u5230\u53cc\u65b9\u90fd\u68c0\u6d4b\u5230\u51b2\u7a81\uff0c\u6700\u77ed\u548c\u6700\u957f\u5206\u522b\u591a\u4e45<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">\u6700\u77ed\u60c5\u51b5<\/h4>\n\n\n\n<p>\u7532\u4e59\u51e0\u4e4e\u540c\u65f6\u53d1\u9001\u3002<br>\u7531\u4e8e\u4e24\u7aef\u76f8\u8ddd 2 km\uff0c\u5bf9\u65b9\u4fe1\u53f7\u4f20\u5230\u672c\u7aef\u90fd\u9700\u8981 <code>10 \u03bcs<\/code>\uff0c\u56e0\u6b64\u4e24\u53f0\u4e3b\u673a\u90fd\u5728 <code>10 \u03bcs<\/code> \u5de6\u53f3\u68c0\u6d4b\u5230\u51b2\u7a81\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u6700\u77ed\u65f6\u95f4\u662f\uff1a<\/p>\n\n\n\n<p><strong>10 \u03bcs<\/strong><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u6700\u957f\u60c5\u51b5<\/h4>\n\n\n\n<p>\u7532\u5148\u53d1\uff0c\u4e59\u5728\u201c\u521a\u597d\u8fd8\u6ca1\u542c\u5230\u7532\u4fe1\u53f7\u201d\u524d\u7684\u4e00\u77ac\u95f4\u5f00\u59cb\u53d1\u9001\u3002<br>\u8fd9\u6837\u4e59\u5728 <code>10 \u03bcs<\/code> \u65f6\u68c0\u6d4b\u5230\u6765\u81ea\u7532\u7684\u4fe1\u53f7\uff0c\u800c\u7532\u8981\u7b49\u4e59\u7684\u4fe1\u53f7\u518d\u4f20\u56de\u53bb\uff0c\u63a5\u8fd1 <code>20 \u03bcs<\/code> \u624d\u80fd\u68c0\u6d4b\u5230\u51b2\u7a81\u3002\u9898\u76ee\u95ee\u7684\u662f\u201c\u5230\u4e24\u53f0\u4e3b\u673a\u5747\u68c0\u6d4b\u5230\u51b2\u7a81\u4e3a\u6b62\u201d\uff0c\u56e0\u6b64\u53d6\u8f83\u665a\u7684\u90a3\u4e2a\u65f6\u523b\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u6700\u957f\u65f6\u95f4\u63a5\u8fd1\uff1a<\/p>\n\n\n\n<p><strong>20 \u03bcs<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7ed3\u8bba<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6700\u77ed\uff1a<code>10 \u03bcs<\/code><\/li>\n\n\n\n<li>\u6700\u957f\uff1a<code>20 \u03bcs<\/code><\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">\u7b2c 2 \u95ee\uff1a\u7532\u53d1 1518B \u5e27\uff0c\u4e59\u6210\u529f\u6536\u5230\u540e\u7acb\u523b\u56de 64B \u786e\u8ba4\u5e27\uff0c\u7532\u6536\u5230\u786e\u8ba4\u540e\u518d\u53d1\u4e0b\u4e00\u4e2a\uff0c\u6c42\u6709\u6548\u6570\u636e\u4f20\u8f93\u901f\u7387<\/h3>\n\n\n\n<p>\u8fd9\u9898\u672c\u8d28\u4e0a\u662f\u201c\u505c\u6b62\u7b49\u5f85\u5f0f\u201d\u7684\u94fe\u8def\u5229\u7528\u7387\u8ba1\u7b97\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7b2c\u4e00\u6b65\uff1a\u7b97\u7532\u53d1\u9001\u4e00\u4e2a\u6570\u636e\u5e27\u6240\u9700\u65f6\u95f4<\/h4>\n\n\n\n<p>\u6807\u51c6\u6700\u957f\u4ee5\u592a\u7f51\u5e27 1518B\uff1a<\/p>\n\n\n\n<p><code>1518 \u00d7 8 \/ 10^7 = 1214.4 \u03bcs<\/code><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7b2c\u4e8c\u6b65\uff1a\u7b97\u8be5\u5e27\u6700\u540e\u4e00\u4f4d\u5230\u8fbe\u4e59\u7684\u65f6\u95f4<\/h4>\n\n\n\n<p>\u518d\u52a0\u4e00\u4e2a\u5355\u7a0b\u4f20\u64ad\u65f6\u5ef6\uff1a<\/p>\n\n\n\n<p><code>1214.4 + 10 = 1224.4 \u03bcs<\/code><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7b2c\u4e09\u6b65\uff1a\u4e59\u53d1\u9001\u786e\u8ba4\u5e27\u6240\u9700\u65f6\u95f4<\/h4>\n\n\n\n<p>\u786e\u8ba4\u5e27 64B\uff1a<\/p>\n\n\n\n<p><code>64 \u00d7 8 \/ 10^7 = 51.2 \u03bcs<\/code><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7b2c\u56db\u6b65\uff1a\u786e\u8ba4\u5e27\u6700\u540e\u4e00\u4f4d\u5230\u8fbe\u7532\u7684\u65f6\u95f4<\/h4>\n\n\n\n<p>\u518d\u52a0\u4e00\u4e2a\u5355\u7a0b\u4f20\u64ad\u65f6\u5ef6\uff1a<\/p>\n\n\n\n<p><code>1224.4 + 51.2 + 10 = 1285.6 \u03bcs<\/code><\/p>\n\n\n\n<p>\u6240\u4ee5\u4e00\u4e2a\u201c\u53d1\u6570\u636e\u5e27\u2014\u6536\u786e\u8ba4\u5e27\u201d\u7684\u5468\u671f\u662f\uff1a<\/p>\n\n\n\n<p><code>1285.6 \u03bcs<\/code><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7b2c\u4e94\u6b65\uff1a\u7b97\u6709\u6548\u6570\u636e\u91cf<\/h4>\n\n\n\n<p>\u6709\u6548\u6570\u636e\u4f20\u8f93\u901f\u7387\u901a\u5e38\u6309\u771f\u6b63\u627f\u8f7d\u7684\u7528\u6237\u6570\u636e\u6765\u7b97\u3002<br>\u6700\u957f\u4ee5\u592a\u7f51\u5e27 1518B \u4e2d\uff0c\u771f\u6b63\u7684\u6570\u636e\u5b57\u6bb5\u6700\u5927\u662f <strong>1500B<\/strong>\u3002<\/p>\n\n\n\n<p>\u56e0\u6b64\u4e00\u4e2a\u5468\u671f\u4f20\u9001\u7684\u6709\u6548\u6570\u636e\u91cf\u4e3a\uff1a<\/p>\n\n\n\n<p><code>1500 \u00d7 8 = 12000 bit<\/code><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u7b2c\u516d\u6b65\uff1a\u6c42\u6709\u6548\u901f\u7387<\/h4>\n\n\n\n<p><code>\u6709\u6548\u901f\u7387 = 12000 bit \/ 1285.6 \u03bcs<\/code><\/p>\n\n\n\n<p>\u7ea6\u7b49\u4e8e\uff1a<\/p>\n\n\n\n<p><code>9.33 Mb\/s<\/code><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u7ed3\u8bba<\/h3>\n\n\n\n<p>\u4e3b\u673a\u7532\u7684\u6709\u6548\u6570\u636e\u4f20\u8f93\u901f\u7387\u7ea6\u4e3a <strong>9.33 Mb\/s<\/strong>\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\u8fd9\u9898\u4e3a\u4ec0\u4e48\u5bb9\u6613\u9519<\/h3>\n\n\n\n<p>\u6700\u5bb9\u6613\u9519\u6709\u4e09\u5904\uff1a<\/p>\n\n\n\n<p>\u7b2c\u4e00\uff0c\u628a 1518B \u5168\u90e8\u5f53\u6210\u6709\u6548\u6570\u636e\u3002\u5176\u5b9e\u6709\u6548\u6570\u636e\u901a\u5e38\u53d6 1500B\u3002<br>\u7b2c\u4e8c\uff0c\u6f0f\u6389\u4e24\u4e2a\u4f20\u64ad\u65f6\u5ef6\u3002\u6570\u636e\u5e27\u5230\u4e59\u8981\u4e00\u4e2a <code>\u03c4<\/code>\uff0c\u786e\u8ba4\u5e27\u56de\u7532\u8fd8\u8981\u4e00\u4e2a <code>\u03c4<\/code>\u3002<br>\u7b2c\u4e09\uff0c\u628a\u5b83\u5f53\u6210\u4ee5\u592a\u7f51\u672c\u8eab\u7684\u786e\u8ba4\u673a\u5236\u3002\u5b9e\u9645\u4e0a\u4ee5\u592a\u7f51 MAC \u672c\u8eab\u4e0d\u9010\u5e27\u786e\u8ba4\uff0c\u8fd9\u91cc\u662f\u9898\u76ee\u4eba\u4e3a\u52a0\u4e86\u4e00\u4e2a\u201c\u786e\u8ba4\u5e27\u540e\u624d\u80fd\u7ee7\u7eed\u53d1\u201d\u7684\u7ea6\u675f\uff0c\u672c\u8d28\u662f\u505c\u6b62\u7b49\u5f85\u98ce\u683c\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u8fd9\u4e00\u7ae0\u6700\u5bb9\u6613\u6df7\u6dc6\u7684\u51e0\u4e2a\u70b9<\/h2>\n\n\n\n<p>\u7b2c\u4e00\uff0cCSMA\/CD \u548c CSMA\/CA \u4e0d\u8981\u6df7\u3002<br>\u524d\u8005\u662f\u201c\u78b0\u649e\u68c0\u6d4b\u201d\uff0c\u6838\u5fc3\u662f\u8fb9\u53d1\u8fb9\u542c\uff1b\u540e\u8005\u662f\u201c\u78b0\u649e\u907f\u514d\u201d\uff0c\u6838\u5fc3\u662f\u5e27\u95f4\u95f4\u9694\u3001\u9000\u907f\u3001ACK\u3001RTS\/CTS\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e8c\uff0c\u5168\u53cc\u5de5\u548c CSMA\/CD \u4e0d\u80fd\u540c\u65f6\u5b58\u5728\u3002<br>\u4e00\u770b\u5230\u201c\u5168\u53cc\u5de5\u4ea4\u6362\u5f0f\u4ee5\u592a\u7f51\u201d\uff0c\u5c31\u5e94\u8be5\u7acb\u523b\u60f3\u5230\u201c\u6ca1\u6709\u51b2\u7a81\uff0c\u4e0d\u7528 CSMA\/CD\u201d\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e09\uff0c\u6700\u77ed\u5e27\u957f\u9898\u4e00\u5b9a\u6293\u4f4f\u201c\u5f80\u8fd4\u4f20\u64ad\u65f6\u5ef6\u201d\u3002<br>\u516c\u5f0f\u7edf\u4e00\u5199\u6210\uff1a<\/p>\n\n\n\n<p><code>\u6700\u77ed\u5e27\u957f = 2\u03c4 \u00d7 \u6570\u636e\u7387<\/code><\/p>\n\n\n\n<p>\u7b2c\u56db\uff0cVLAN \u7684\u672c\u8d28\u662f\u9694\u79bb\u5e7f\u64ad\u57df\uff0c\u4e0d\u662f\u51b2\u7a81\u57df\u3002<br>\u51b2\u7a81\u57df\u4e3b\u8981\u9760\u4ea4\u6362\u673a\u7aef\u53e3\u9694\u79bb\uff1b\u5e7f\u64ad\u57df\u4e3b\u8981\u9760 VLAN \u5212\u5206\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e94\uff0c802.1Q \u6807\u7b7e\u63d2\u5165\u540e\uff0c\u5e27\u6700\u5927\u957f\u5ea6\u4f1a\u589e\u52a0\uff0c\u4e0d\u662f\u4fdd\u6301\u4e0d\u53d8\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u6700\u540e\u505a\u4e00\u4e2a\u8003\u524d\u901f\u8bb0\u7248<\/h2>\n\n\n\n<p>\u5c40\u57df\u7f51\u4e09\u8981\u7d20\uff1a<strong>\u62d3\u6251\u3001\u4ecb\u8d28\u3001\u4ecb\u8d28\u8bbf\u95ee\u63a7\u5236<\/strong>\u3002<br>\u4ee5\u592a\u7f51\u547d\u540d\uff1a<strong>\u524d\u901f\u7387\uff0c\u4e2d\u57fa\u5e26\uff0c\u540e\u8ddd\u79bb\u6216\u4ecb\u8d28<\/strong>\u3002<br>MAC \u5730\u5740\uff1a<strong>48 \u4f4d\uff0c\u524d 24 \u4f4d\u5382\u5546\uff0c\u540e 24 \u4f4d\u81ea\u7f16<\/strong>\u3002<br>CSMA\/CD\uff1a<strong>\u5148\u542c\u540e\u53d1\uff0c\u8fb9\u542c\u8fb9\u53d1\uff0c\u51b2\u7a81\u505c\u53d1\uff0c\u968f\u673a\u91cd\u53d1<\/strong>\u3002<br>\u6700\u77ed\u5e27\u957f\uff1a<strong>\u6700\u77ed\u53d1\u9001\u65f6\u95f4 \u2265 \u5f80\u8fd4\u4f20\u64ad\u65f6\u5ef6<\/strong>\u3002<br>\u9000\u907f\u7b97\u6cd5\uff1a<strong>\u524d 10 \u6b21\u6307\u6570\u6269\u5f20\uff0c\u4e4b\u540e\u5c01\u9876 1023\uff0c16 \u6b21\u5931\u8d25\u4e22\u5f03<\/strong>\u3002<br>\u4ee5\u592a\u7f51\u670d\u52a1\uff1a<strong>\u65e0\u8fde\u63a5\u3001\u4e0d\u53ef\u9760\u3001\u5c3d\u529b\u4ea4\u4ed8<\/strong>\u3002<br>\u5168\u53cc\u5de5\u4ea4\u6362\u5f0f\u4ee5\u592a\u7f51\uff1a<strong>\u65e0\u51b2\u7a81\uff0c\u4e0d\u7528 CSMA\/CD<\/strong>\u3002<br>CSMA\/CA\uff1a<strong>\u76d1\u542c + IFS + \u968f\u673a\u9000\u907f + ACK + \u53ef\u9009 RTS\/CTS<\/strong>\u3002<br>\u5e27\u95f4\u95f4\u9694\uff1a<strong>SIFS &lt; PIFS &lt; DIFS<\/strong>\u3002<br>VLAN\uff1a<strong>\u5212\u5206\u5e7f\u64ad\u57df<\/strong>\u3002<br>802.1Q\uff1a<strong>\u63d2\u5165 4B \u6807\u7b7e\uff0cVID \u6807\u8bc6 VLAN\uff0c\u6700\u5927\u5e27\u957f\u53ef\u5230 1522B<\/strong>\u3002<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u8fd9\u4e00\u5757\u600e\u4e48\u4e32\u8d77\u6765\u7406\u89e3 \u6570\u636e\u94fe\u8def\u5c42\u91cc\uff0c\u5c40\u57df\u7f51\u8fd9\u4e00\u7ae0\u8868\u9762\u4e0a\u77e5\u8bc6\u70b9\u5f88\u591a\uff0c\u5b9e\u9645\u4e0a\u4e3b\u7ebf\u5f88\u6e05\u695a\uff1a\u5148\u8ba4\u8bc6\u5c40\u57df\u7f51\u662f\u4ec0\u4e48\uff0c\u518d\u770b\u6700 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