--- url: /notes/计算机网络/NetWork/index.md --- 期末考试习题复习 **第1章** > ![img](data:image/png;base64,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) 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（1）数据长度为![img](data:image/png;base64,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) > > （2）数据长度为![img](data:image/png;base64,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) > > 从以上计算结果可得出什么结论？ ``` 1S=1000ms 1ms=1000us 1us=1000ns 数据链路层以下：1K=1000,1M=10^6,1G=10^9 网络层以上：1K=1024=2^10,1M=2^20,1G=2^30 ``` 发送时延=数据帧长度(bit)/发送速率(bit/s) 传播延时=信道长度(**m**)/电磁波在信道上的传播速率(**m/s**) (1)发送时延![img](data:image/png;base64,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) 传播时延![img](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAMkAAAAdCAIAAACPC99rAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAi1SURBVHhe7Zt/VJPXGccv82Cw58BZmaEVBsPzMjOktSdt2ECcmFQJtp4I9gxB6ogncGacltAd7NBD8RfaGXeC1FNak2JRnOImE1A7YCSDGVADIgxk0EQYyiRqmPj7hLrs3ve9bxKSAMHhadD3889773N/vOHe7/vc5973xctisQAGhmfA9/D1hebxf27dG8FphinjBdfWUJM8OXlLaX3P4CNsYZgyXuw10aDK0izesZLtzX7ZB5sYpowXwG897r1Qc3kAZ8hcTU1D5020CPZ3Vmnq6lrLP1yy+yKzKE41z7e2Hl4pTX0zfk2GsKSHMhgOJUj/7jcvxKRYKDk9BGZ4L0lJTYiTyJIH2vupGgxTxvOtrZdeFcgb/7b7bZwFF0sVvLzMqFCCJ+RVfllrjH7/9S+khSr5vhvvLifASM+heD+f1WVNZalhPl4h22ubC+P9vHwii67g5gyT4jlfE/0DA+0DqQd3/EJ/MFi7ednab8Lib927770gs+roB+nZB7e/EwQefjP0+uGT0oqtR2bu6mgvmrNNcjT88M0ayb0H3+LmDJPCPW0ZVIsWqQw4AzRZXlkanLaDrgSvXi5w1WQ0dv3CpBW7OyPo7h3MbtL8oWBjV9KJ2i1vz8EWKy/Nj+INtn2dIN+VOHfGQPeNrWV7lwUM/OvfKYsX4BoMk8ItbRk0XwExH9CaERSAAgGVRDiKhkjfKYtR6uEG1KKWAZkaXvXKGJmIjwrtRTOO3PgK1By1AzFiPmHfKg2UkGXn0glc2X1CInhLFcoPeAGg9YJuSUQINlvpazkbKOT6A9DVUpccF+0NjM1nWAvYTZpLD3ENhklAztP4wBnGWkGoaeHYgTRgBakJiQleSG2hQlJhCFpt9ikaJws0ONwL9+s22l0cDifIF/gGcTi7tBaLqTE/lrtiQ1osN1ttwnVsDFet5cjbYALeJuH4IEwM/imJ5Sss7jaT5QyTwg1twRm2m3NX0qKAE4KKkJRcgzoZrS2ly7r4BvbKoptNVlseCxpUK2ON6DRnwjXRoMotQFd6WRIUaDPCqCSNXeTTeWDRAeIc6phUmhJKQmaViIJcFe0h0sm6GFpA5GqnyRIUyHa6WPfo5fjp4i0PwWDQ2QnqaZb3acAE2jKo0jIioTroCEivlDk/Y+TQoJparS6iBCoI6RCGRdSQiRSWEpBmpwYsDhi1QWBVl1GXphIWUzUdRET7rWk9If2d2khi1O+nDkAii64MtRauDPDxCdt98XEPeRjit/okPvkd6Slb95ofGhO/H/6qwkgZPZcJtNXfGalWiHCGDOoLHL0WKQ1NVhrYCT2VmN8PdYVkQ3o3HPWHZWiR4y+h1GBbEyF8hRoIXKgLB/PI/TlMguczar8Ccfaw6Mmh/S/1x3efrAv9Q4X0H00HSluWlg1USQyHP5ZW+Cu62ovCNR1YW02qtEd5erPFbCwRPJkxizJ6LhNoi68YtZCNXsOoiGgjqsBXnEundl1QFPTaZlvlxgnCXKvLeujR3wmct3NWqNn5zsG/hoZ+LmicPay1BhyXAvKP5yRL+Xf72gB45/30+eSR3OyEHNmyAO87xhupi7lkK0D8bKV6z7663icBiYdVK/woo+fi1hkEDTpasqoAPp0CoB5jZbKte1SK9FxjAUfaMRQj+GKQkabSqHJ1Yj51B7Ij2A/9vCN3gGfoqRk8tWmN/M/VKqnos05sehrI30fjdLznwitbIYhIEIMfnrsdmkbpOqE/TLY2/jFhU+I8bwDaG469FTUfJhBB75V2HHyj4r2Q+NLpEGtOSlvQbekjctGsalSLBDql3jk6x4znt2y6GwcivUQJMgQZgJKWoytATEHAdf/Wte+/tjA6Opw9dW+qHXy7qy0MDZShoACd35G5yw0nllMyMrTX+seEvwJTfS1nfQTzhw8VnLnddyh9Z/OTAF7S3h0J1cUNfWQbj2ZS2oKQI1cCcjO01jFxxXh+a1S8NREobBvvwf//IFZlsja/yRXphIk/xqZnjy0cC/tKrLc+Iu0XK98QcpGg7nY1NC9/KxwZZ/nPuZqdqAr95buzH4xc+0Iwy8trZtD6of2/XxmKij0ccp7HxxY/2QOttm00JRScd1GfPJFw2mBS2Pk0azPUH50ZM1ajKzy6er66urq+w+jyhNNs7Kg/1zNsl4OVz199hHL12WvLTRaLqXw1dVTqFsP12UlFzGnqxLijLc+m49PV2UfPX27aExOc34JtNIP1ebHcKC6b1jWURZSkvKu3Sc7nydvMFv0RUWzKRx9tSBQfGUP4TpgvbBOipgwTMv21hTE3bg3OrieTeqUSezSzccBotvnMweMJy0uvw4RJt+On7G0XkM0OkzqbYAXnqxvzo3wBK6FUVyUlWMBXWk07Pdhhm1yYXU/mTeqcCF/oPVnsPC1ZxuDAZOMtD2Wkp2R788fp0aBbmbmv/fa3105n5qsfAu+AwAC8x0Lcv3eLEzirVZW6SvFf3tw7D7AZYzR4iysPhHzyO11cxc0aySnJ5usbO9qLwu+bcQV4ly/zen/z28Vo939b8/nZdVqz2Xhk06uzqWIGB7DGpjOmS3Jh1LZG6t2zuf/M+h+9LCruIgMqhM1vwZQvmysth8EWTLqIIdHL6j2X4IIHi0kPZ1bLkqyRmL5YKKmyvuE299fkxBKi/Zec33kzkEx3vzXSU5a6SvkTZUNeNDoYAvrSwitx6/eKQ48XNjh9FxNCRAZuOrg/ca7PUPtf/XjzsNnG5YZTooVcb7RTm/mLmCAAWhsaucSwBu34B8q2/GXd9hXkXcDd07mfGH++u7Zy6dGcs9dJE4MTWGPTE+hWYEAUxCFJOdZLWW3xVu+xFA6HYLNYbIIsNncfX8ONTduwgity9d1Mm5yztgoGU7DbYCoaa8kPZhHocxxTlURYbIv3/1kcx2bB0fONyHHxrQ4DCfN/1e4wVPtriSHzxHp0Us7gLoy2GJ4Vz8k+kcHjAOB/qALFxVuqAaEAAAAASUVORK5CYII=) (2)发送时延![img](data:image/png;base64,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) 传播时延=5ms 若数据长度大而发送速率低， 则会对发送时延产生大的影响；数据长度短，发送速率高，会影响传播时延 > 1-24 试述具有五层协议的网络体系结构的要点，包括各层的主要功能 法定OSI-RM：七层 事实TCP/IP：四层 教学：五层 （1）**应用层**：通过应用进程之间的交互完成特定网络应用 （2）**运输层**：两个主机中进程之间的通信，提供通用的数据传输服务 （3）**网络层**：封装分组，完成路由的选择 （4）**数据链路层**：两个相邻接点之间封装帧，传输帧 （5）**物理层**：透明传输比特流 OSI的体系结构 ![image-20220428172325404](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281723488.png) TCP/IP的体系结构 ![image-20220428172338858](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281724552.png) 五层协议的体系结构 | 5 | 应用层 | | ---- | ---------- | | 4 | 运输层 | | 3 | 网络层 | | 2 | 数据链路层 | | 1 | 物理层 | > 1-29 有一个点对点链路，长度为50km。若数据在此链路上的传播速度为2\* > ![img](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAA0AAAAAoCAIAAABYTg2/AAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAABvqSURBVHhe7Z1NaGXZVsfTguLAgQj9EBprYIo3MCgK1uNJFUgCDhxYAxFEeFDFszLRHiQDPyYtQvHAj0EyKHGQDKoGDpw4KHkIDhKFCoJBQehChAShUKEHgo83eI0OyvVfa+291tof55yb3HRVXu8fdOfsvdf33neffW9O3Xzw9u3bjcFgMBgMBoPB7eEH9OdgMBgMBoPB4JYwDnCDwWAwGAwGt4xxgBsMBoPBYDC4ZYxn4AaDweCL5fP/+pd//PSzz3/4o5/9ha2v/KB2DgaDwSq8v5/AXR4/+GD/VBtr4nT/gw+WGD3df3B8qddLoXi7ShP2KCQJKOjnXoUDV1SqFFmZZsBTWRCIo+3Vp3jt0G6cIs1yfmiYE9BEknQzr6SL0tREu4Dk6s4KF1G7mrk3pFLK+qBUqm3OQxJTEZbD3SUTBzp+kxD91DgDjRwT84mwTEfona7X//zL3/jG3/zQV3/mzmd//PO/e/p/2vsuKV8BCipzHDdiTJQ0UdyKppnBYHAjvLcHuMvT52d7D7e1tQ5o59k53NvbO9xZsFuf7d7VHUnBxlTcZFbZ9Jv2iMvLc81yc/vxxvNT2f2sN3P/6OItcXF0n5un+zuHG4c7amy1WHpgQ777+ukL77hImZx6r0A9bx88fX33Pd+9LZm7u2d+RnYOrYV8Np+82PokzdDxg0cbL1492WzNSkCnyEiT5Tl9eXj/8famtq7Mu1s3lMDeU6pG4vTZ7j3fztAreOPx9kaqefRbOd588nRPYz3Z29g7kZhTjk9ePH5+Fyru0NA0eDvW63c+u/zK5k9+9OObd3/qR7/7+fe0913C5Wivhs0nry7yqyE1Ibp9gNkK0NQNBoMvDn3lvRe0bngVvLevDJsWVVxW99rISbqX9OG7TGu/aml27VnGJECN+0cnZQ046GyAZS7YbyoEbFylKGKKLyWPlhET4oS5j3C6DurVaK8UUMFV81pCEX8xP/BcQONFL4Xmp5/eGehVgO027NVIBKl0LiJXzXxpFiWwta4bksrOI6yfYaHY5RTFozYsEIclQSAS6sAPzrKOrjTBYnqdMa9hOAaTUH9tS7Mk7avwvdfHv/zhhx99+LU/+If/1q6rQaE3ErsajYSqysyUqjXNg8HgplhygKMXNrbYJS9NFS2k6VWvLHx5w8yVN8ca9u/twf5UKL19yPrJQiFS9xjdfe1kr5EmWSp7rYJUw709eNKtlH503U4jAVe1iUDofnE0CDSck07PIoYMp2sJZs0JM+thxoHE6sPRa7oKkUvDzXESiIIETE6npLPqraUuKKfOG103/aEUilyTUMzQt+DZoum+AJIOkmtTpNQWzNZhbo3r1fszTfThyLzHx2ZnUYULHyiFkLz8x7e/+fXf/Kt//ffTP/y5zd/5++9I51XwE7IWLN0Kzio7tKSE1Nuo72AwuCFmD3CyEcuWNffSJCkVcvJeFdfzGw6kmlxhcxBbLZ+8A9lA1ynIjklKrmUjy00/JCyx52RCIBjOOyXTuFtqBs3cFlGaa2JCIaBCVyKZRHRJrxGw7yVTarktex1gcQ7LlmLWT9UQBd2qU8pkxsWV7lnu3kUC+dpjuYHmzS5V2SqKIIoPpFweFog6TQaEK60b851RYW+cTMuJUNuEOZII2x9RKyYJO2qWLRyRF0o6mxZjqmE+LJhm6X2srpuZCCshuqaHILwJtN3GQMBovVOineIgCR767re/+bU//zf0/O/f/tZPfOufePAKeNvXQutR2wpFBLkjjLhen/tgMLhZZp+Bw4MOBxMP/ng2n7zCs0K42n58/+z1G1y+eX2Wn5lB9/nl9HMnp/t3d8/qrUR3zJU43cczXaSbEqCO/CwHEsPDHPbgR2fv8Y7Twzj6sBE3H/UepJm19+b1PWz4kDu4ww/vkOXT5/x4VnrCR6LbPtDCZiiVnUPcISHVfHaljzxIVDwHFmk+HWRPE5Gu9jHxaZjqvoIct+6obM3ps92No49lik5fHm6cpUe6EvJgE0KiqwfHxwj/wfFp7l0KrU+NiGNszg/qjNpuUAIHD/mmxqtk5/XTp/c4MDzbFbJBFTEDuZqhsjnA0/2d86MXrafFmqToEMThzqONF/YyvPl1U5amvQNsffzq1eaz2srl8aPde3z4lYVxcbRXl5oDg+TZ2fnWC3KAValPG25sPDx4+2LjkdRvA9OGCVO0tvYMHJ50a3H99drc0Xg9Ptp4Slk9RYyaf3OnbK7tH/n6N37x2a/+ym///uNf+r3/+dNf+2kebUAV4X9CABfymg2lxkJMthmRYVZ5WUjorsDGna2VN93BYPCFcUP/iAG3E30AmfaAw5e679B2dpZ2wSa0BX2yRe/AbevN2B5cPKjcgbaw5pbq4Tv6pEQFndmOznfu7uo9fPPJ03u7z3r3wRm2D8w3ng3GFpoOGelNrUhgK4cTOxe8fMiDfCuK59B55P6F25TcV+0qU973y5teS0Jxc98kz61GTIfhjXubfDd/QLN/cpRvlAz13n3+mKJTh2e7z7cuTvbOdulIRYFPLqcOVM27u/dOuhnIuuG1eEH1lyk52L6ztUHOcNuUf4Ug63DnUA5Sl+e5hqGe6gX/egD/esFusv5fTszM3l6M9V2tG5BnT09N2wewEs8LOGDi3KlQxQ4tU4G9nu7jGHSfyvKGqgKDHKeezPgFf79x5OXaUp75IyO+LlnbehW8FGr96smdjfPXfLa0yajorO0f2/6TTz/96z/7o+d/989/8etfnfoWkcNdXuWHO7QUKU3/7rf81yOXx5+cl6tudWx9Eg+evQ4uB4PBe8WVD3DuhV6928OHaLSFp90OJx6RfLmV39u2ON2nbYq3nvCGWODbFJPuVdOsvoW5+6mnePdO7p/SDYO3ZbD98dF5OqBG5uzxAYBaLJeKmOqaP18I1dVzAW/pLMag2lO3kTkmTqFvXp/d28TttUU18UA+c8AHQ3mYjXC53NThMyBngPLGp6W4LzooS+l1c6mf594PHz4shWvOZw9fQCWdZWQOSCrPII9sbj8+/2T/WTq/aTLu9PD6mbyzSHNKiEnyyj4JO1eEXzetMnvvdN3kV2bOm8pwkT+H5nn2B0yieL2Sos4dPh+U6aaqULedx+TKXvIGGXv1hBbkzsaevM+jPN3njGter4mwoykUycLatdf2ItIqD//wF9Bx7TAeOzc372FFNJNcjpzs9R3Iq4OH97R/MBi8f1z5AOfe4MajEu1W+P2T29tsAz/YrLZGj23EjbtreY5aM8VdJhIyxK/C9vbOP0kbZXsjX2CPRfJeqS5SXfNdLFY3427++VZ6dbYPTjb8cSpxeXlOB27EZPdXgFtr68MRFIe/ZQK54XdgsClGVCCz/VDDphsPzTcd3WXN0N3TpPFM0XkrsCuBGyndh1PJI+60sH2ARkoXmcudEgfdw8P2l2bgpr+15afFTOKzEn446tpQBvun79G6USiijjsC5838MZ/sDh1hfdXnM2jzJU8WZIOR32+/xddf5AVyI+u13tEWM7W2rwU+By7fwcgS0N8854qvxuXxcVC8s6XfUcMrT/oStkmndyeDweALZb2/QsVe3d/r8DnE+bLPTdzem1jLDbCPblAUo9wN7LYTty7Z8Q8Ont7b7T78BpbaE8p981qQg9WPPHRoefy8+mIs+yyC7g4PX/J9AZlUH4sx5JgmGL91ZHBThFD9gQaBTxD0C9FwlEvfjea6BTJycm+XvwNsAsQEpsX4DrfkPnz5ZvMF/34RyO9RAeae7lv56O7At6N1fw1Hfpd4LXmDpMoZiQeAta6ba0MTrVcemkGuJT+16NdHhb7q89nLv+TFNlYYP51oJjCp+Svd1r5eoXzV0xuYXNtXp/z1qQNZUOH8bz5t75nh5f7d5xvhgImP9fQhheroGTbpqxZoMBhcA339dSnPTY2jVaZ8Sy/v9s3ClK4jvnlOkJnG5yarQZabNhCiurRLCyPcUbKB4l9c+fiW2iMwzqXJFzoQgMaRCDhZw2uR7KJCkRHIsa2kQLrOGIacZR4U6iiDmYD6SddqIcpav3U77zJMjdSnOaYm/dRmHViNWGvglUWI/0lk9izBoQwueCwDfJtEkomYSRp0WkTzX+y5Gicn1JWsOBvqa43rJqPFbeCjC0VgYN0MurAFdl4Zpl7pi7YTcawTViIG4C3WebajATkiogxqKgC26Eg+rX8m/AryDpWUljarPBUfa/DUFi9hdRXLIZMdupb/8xhJTZgSWW0MBoOb5r36Il8lbhJ5M1l5/6vJW2AkOIQ/abluuYyBKdSp5LGl9giMIiTq4Mgs2wTJiQsXOUm5VnBXjE0gVhsF4QGyKJYsIudEdQF60SzsOAmveEOkIBd5aleIepN2KkCmzA/uaFxzxBGJR0vDzqQO8nGwDWmyvTq0VikRASRpLLlWiUSOzxmMAdKwmPMOukA0a7CSmPKenfEga1CvCYlfbTfkU7hpqE7SwcdTEjchZ048MehF08dKOIkqjvcMCrUIfppUvkm01ql6XkH6xGXbltV8pcAGg8H1GH/MfjAYDAaDweCWcUNfIzIYDAaDwWAwuCnGAW4wGAwGg8HgljEOcIPBYDAYDAa3jHGAGwwGg8FgMLhljAPcYDAYDAaDwS1jHOAGg8FgMBgMbhnjALf8e8oHg8FgMBgM3gsWHODyn36ik479YZ/cq1A7o1KlSIuGmbYOOdeB0321b10NcCwr/wxRG/57he0/R59dFcn34TIs8+uML6DjH2m6IvjaxDhiYfvZkJyNFNYz1M/d7KWmPyuKcx9MFIppLIbKJZ6ssTOf04atyo75cyqAmrNJXJXCVYsytFYsQYYo25E0Sj87zqf1jUV+XY55nPrWPwNOC/YzhW4a6+Q+gYsjhhRbHhpZ3U/JwukgsS4uCBfSuuajDLATMLy0aUmvhyL0FmWqndDrblIsbS+shJJGG4aUaf2VqavRvPOQ1y4mPiVVRL08DUgev4N18n2BfJ/vBBf2dfL6bd16Gb+RO/9hoCTkv9octL/AO35zd/093ySi+lNAqfRX42LXng4WVA6oCrWmE0BPTQu2wDBoipFHdNKYVs1CKIQheb+fdS66WJzLJDvMUfmLKpYqmixtUBeiwA/DC9lICjbKEirurLtLAgqlyZw54pUGAvdiawcOzG+iSqdFOzEiR9/CDcacM9SdexFexBSW+XVSUQHevT7app5tIQIn5gOK3ut4sk38MEqhxYT8rNHwm6ExU4m4THoiSvPvrFXEMIKObzixqEGtK8wHEc0QoU6OTj/pzxTgWiDg2j6ym8XSKmMU9dLs4kowbhDmGoLeK9KI9C13aHlpra2YRnclgZZ6XYa2WItuwbwFV4qVa/B9zQp/C5WqydOEP/wY4IrmastUcsFTqWGjXkWiLEDXPAk2e2xBDWQ/xbwX/rnPCZkBfzmPCgejFTRK8RZGubNylAPy8dZiJbV/r0bXfOlXvIedXlzkodqaEEraFILXBI+Ka5HFYFJx2lVUbkyAYlGCYnYVrxmtUEvlnbu2EcfJCUVNUk2KqK9Mz77Bnmx+QsHqHKI9iKJ+Hh95WduyDdQhD6U/C5awYBb7Xe8MkBOLIBsW3JjQyG42hCmiMllHq/IaUKEGJ3tpAAlPmChtICtH1iz6I2Z/vfPBwRvoK+PwrrWrYjqM1eh7SXBEi19hjJsDse9UlFUqIbNVzmrpWAPjof4rcTGWWrdEMl7GHYhuSbSKo06FespcHc5Ap/rRz/JXzpeO2QOc1c5RTA/wK+T+3h6Kr3NDP+qSu9UoMxUnsuFgEu+9hzqMpqllfpuRAglRGwHos5IT4b6WJSfjX40IXmMQ1WmgWOdLBrxNc5WueqZT9hg3/WAsQoLQ6ZYceuaeDbX/BKh4Dn6TVzKe4nI4q+E6xyTW5mhYFuqc1Vzstsx9f7u3ZTQyN17i5KUGsVa5EgAxldlySq4zqctPMSkjwLwt9cv2Z3B6kboYLiAMrmklzRKymHYbyXWYojUvTFU8JOFK0L0uShcnS2316UZcz0dhmq476wB0ip9lYmzRCnqic1RNiEYbQQbmxptIjOKylQOxYiUqM5yk60zq8lNMyghYOYtkDm6Cl9pO9BUkKvGQFhMcoBGAurdfXMscB63Uk8UcrTp+qZk5wLnCWtm0tmmBCDzRZdVR7mbB3bKAzv3iAE993HbuexSzHCKIEQps2qScPElnVQl8isIvkXXqIcZHE18WSLOjRLDd/jCDYzasGKoAZb7kvFk2pqydyQn/bGPqe3RAdxbwVpF6XK2Di3SluDFu+NSSsIsCRiEV4I+BnR5i0ujSu2zrqkn2ogD1hlARBHXQD9+tvbiEGTXR7s24fDwQSwF3RBI5hIWvHDFYxiEgwmTQ3LIsDwWSt8V+1zgDhOtax0paCZgslKoIZ6aNKR33Z4bJeZIziHmfxbU6aGBRrnc+LDoZ7q8Dol8clSGBOiRokQ/64Z27WFr167iC2KqvMCbk0WZxJVrxCiSz+itxEU496lWvIqL25SjFSTh0QbnIbuEK5oxTstbJV17F6FfyS8vMAU4PBqmmXHD5abiKhrLr/MjCjGUv1j5dl5rlvArF6vPj4qaJ900q1DTF5AoX0ZdRDWUlgaxlP3JdW/KhwkAhUVg0MFB+lm4eE21dDpyALmmokIskeYWcfGjK3dTuGIRk8icx0FU2KIPSgyuBxtBOFp37IIfxVJYUVwDCXjNfc6uQ95YNp6I+NJ8GSRaWzLhvsQ8Wa/f2mZSpkyfx3LPslQMHdMrWVEpIPERwcbSXr3xZvbdlfh3socJbXzIDwQp1oJ0c+QC8HMYnV9Iy2GSdlM+ghvzNCkxL5IiTL/qZo/D+YyxuftpRUqfWx+PlxDMCbMOyK6+DKZqBKoi3Y4qcdNUUzrYnVAdJ4trDijOI6LJKwN56X4krkBNlJxXm1fuaW0mwZeVrzIX3ymP0Mytki1Ckew4PODfq3fUkSKE7o19i5v8Rgy+mnwqbKIZbNK6Lg3CDUHQdmAtDjaNTJILhKOsJsxl0HEW/NnNvys3lWEKyxVDSTtnKcMg9kYeCifq134T8wFEtQj2WlETjhehasjzC+1juRlcLNgM5pw+3BdkG9qL6CG+wvWBLrlLJQpwZHTXhpog5KKxQS7oTMHAUD6Gl3xxQpu4BpOemHy0WQjj8izWMtXs7cCINR4k6DJ8ea2fUDTpFolYuu6gZgkPsSvmxJoRTc1W/a5oBp2OLQ4VKe4yOmnDpcgFs3urSXu61a4LtFyk4YKepZ4SKp0CyxWbKTJFoBcbX8YqIFVR9dIpg0ohibeLD1GX4/VrB9mSy7LwM3JGCNHyNGeuohZWYYrcSjqKLmiENZKxMvRKXYqGsxrwnWzgtH8tWMJ9U04AZTNquh6H29Jx/eZk+wKFwGaoglxzTFuDS8nRZ4YMmcBPt1ogpEDrjaeIZv55614TX6V0TSSt1I0q6CFEEIEBDKpe6ojAZA7ETGqpSxGCocW0FnHrlTwYdloGMOHErk/0iIfX4Ejon+VcuDCwGezkp7TVNuuIxZ6uScmPZVtJLwj4uARL8MSQeRbJslaSv6KC9meUuDTtRzonOYVimDAasj1o5CDPb7pWrecw6KAOLPa40mqagMrVykCI4VGtT0wVQx5tkV/OrItefAedrTStpITAuvxLzYXqXNTLad0njofYtuAjkzzzRVe0/12oC50r11vCKWG0dGN0BBc5cwAR6GiqFINKYJ9qpY6l6yGzqqAslrFyJIEWQhG9T0wVa5xV0Zwn6sjeViEF2O0PlWmoC1boyKQ9Ll658XmYtDcBchoeDmAhUQQyEtX8Cp6JxDoJoXPvOhOC3QG+ldw2cfRqidaCtGGL2ltVpvH63k4Ep75JtVa68B4a72xYzEzLFEDULOeoxl1It1iFKi7mWEMBlLEjGnHBF1EhSMrI6XTTgMbNl7hNuTGzwkumbxIjoqCb/oAlzSWQDTI4w+xI33JUxKYipo9TwMaPDlINsNtzubUGSvSGlqpgP1Y+2TE2XG3hjFaW0mVvJr/lIBlslcZGQWHsGXEDTqYkD6hIjaJaU/qfg2FyASnBZgLBZfEpoEbBk4eac5Lo2TWHy0w/+CYiIJZIMoD5Fbk4qRsCNZHmldeDChcNAqQovoa/qIDiUymmkFVakWkk+dSF0tCIJVloup5crqJx6Suk65pWofFXRAJKaWUkJlKS+12RkOHmkVnYe/KaB0MnUPYMuiw9wF0dHfK62pRDXBbes9HESvOgKa98b6V0HeIDebwSratEpLbFFIUczTE+a+nlnAk2BDOx2ZMRIHKodelcERoOQaxS1VOkaU7nQ7xBwnyg58jRmw07TXo8cF1O4M2lGSlEXOYDf70bN5EnwrRyfIKE07KucZhpCZCVTIZEi4tSEssq1e2ti4C38hDHBvxttmSqVgy6IqQlSI5Rh6veni/2STz8u1htJqxzKVQRpYabQmEKIxnwP22n5uQq84nyALZwvxGnBxFYGhhrdFdkhC4cSRAMqSHGkWrBwUQNNIyH2Chmgcmy0DBNKrLLK+oOlJFEEUcFeowR1hTBauTVohRUJQYLSUx0uwiusrlIJovKRS+rgFLn8M78/hWA018LMlfdDDHl95EeQTBpg3SorIFZFtCOi5uZWMA001Zvh+fYgsOwAh9rz8UwudCBAdcavuSDgZI2kleeXKW3RaJjj3JDrbLWKQUYgjkDcqDaDYcO7yHCIlQdQ2BZSUC37mX7kAnw2DNTxUY+ZkJd2ELIQXbd4x2+FWiHUTtoVyKZ5uILHzFZttejJVgqxBl6TrlVPkZjQnSJWy1CpMknqM06LFLO09Xuj7d4CEpoYBWmnNnM+yhhSaYpGTZiTLCTQ581JIXIPNf1ojmW5XxhMo6qDEb70WuJ4dgYsoDK0qidHOGNyOWSxLl9tnR2X3ZJfVIfgbHBOSC79R83ZP/t09mNgbhRxJCnthiBf+ugk3vn41IbiLQAaTQYgKL9i4x66KIWJ5BW44ehETXpZpmEPtD15pl9hjBphCbXG/p1gDLJ0SaMmy6qFBPq8W0kv91AzBBXPbxCeTFKsmbkYrCCDOpKtRcdxtLQKRMIHgx4VkcvmCtZGJ4sYhTc5aDB/gMPUoYJUSS6kTqWDZkLm0hU6TgMNy3T5brqWTlEWls1qJqvaqLcGYFFdlUMRmCDBMgavZF5YUGgGpjTiW4BzWeppJsk9hxrTStGTCCnLmLdikaukCPKlA2K5EKoj7ZY8ucnCJRaeqaEvKcTwHVnce6Rr5yn5lU0uWSpDkX6SyIa6PkE3kyuhtVtgN+7UBc0a+DTUOrszOw2Jin4xSGOp3y9iBkwnJpjEuzZNfBlkqAghp55gX504UyQruPVpJLxPPw2B3sC658P7yYF5JemhIXPWtVmGcz3gc5ndyVcYk22VpjgX1l5YCTFl/hoSFd2CeZs95TZkMir48AOdAYmprUJwlhiGXBkaDeauYN4PCGIHrJbfl50P6D8t3GAwGAwGg8HgNrDgj9kPBoPBYDAYDN4nxgFuMBgMBoPB4FaxsfH/TFEw4PuXoF0AAAAASUVORK5CYII=) 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1B=8bit 100字节=100\*8bit **第2章** > 2-05 物理层的接口有哪些方面的特性？各包含些什么内容？ （1）**机械特性**：指明接口所用接线器的形状和尺寸、引脚数目和排列、固定和锁定装置 （2）**电气特性**：指明在接口电缆的各条线上出现的电压的范围 （3）**功能特性**：指明某条线上出现的某一电平的电压的意义 （4）**过程特性**：指明对于不同功能的各种可能事件的出现顺序 **规格化内积** ``` 使用CDMA的每一个站被指派一个唯一的m bit码片序列。 一个站如果要发送比特1，则发送它自己的m bit码片序列 若发送比特0，则发送该码片序列的二进制反码 ``` > 2-16 共有四个站进行码分多址CDMA通信。四个站的码片序列为： > > A：（-1 -1 -1 +1 +1 -1 +1 +1） > > B:（-1 -1 +1 -1 +1 +1 +1 -1） > > C:（-1 +1 -1 +1 +1 +1 -1 -1） > > D:（-1 +1 -1 -1 -1 -1 +1 -1） > > 现收到这样的码片序列：（-1 +1 -3 +1 -1 -3 +1 +1）。问哪个站发送数据了？发送数据的站发送的是1还是0？ S*A=（-1 +1 -3 +1 -1 -3 +1 +1）*（-1 -1 -1 +1 +1 -1 +1 +1）/8=（+1 -1 +3 +1 -1 +3 +1 +1）/8=1 A发送1 S*B=（-1 +1 -3 +1 -1 -3 +1 +1）*（-1 -1 +1 -1 +1 +1 +1 -1）/8=（+1 -1 -3 -1 -1 -3 +1 -1）/8=-1 B发送0 S*C=（-1 +1 -3 +1 -1 -3 +1 +1）*（-1 +1 -1 +1 +1 +1 -1 -1）/8=（+1 +1 +3 +1 -1 -3 -1 -1）/8=0 C无发送 S*D=（-1 +1 -3 +1 -1 -3 +1 +1）*（-1 +1 -1 -1 -1 -1 +1 -1）/8=（+1 +1 +3 -1 +1 +3 +1 -1）/8=1 D发送1 **第3章** > 3-04 数据链路层的三个基本问题（封装成帧、透明传输和差错检测）为什么都必须加以解决？ 封装成帧：PDU格式定义 透明传输：帧定界 PPP：字节填充/零比特填充 Ethernet->通过数学概率的形式规避部分出现定界问题 差错控制： CSMA/CD 协议的要点 （1）先听后发 （2）边听边发 （3）冲突停止 （4）随机重发 **CRC冗余校验** > 3-07 要发送的数据为**1101011011**。采用CRC的生成多项式是P(X)=X^4 + X + 1 。试求应添加在数据后面的余数 > > 要发送的数据在传输过程中最后一个1变成了0，问接收端能否发现？ > > 若要发送的数据在传输过程中最后两个1都变成了0，问接收端能否发现？ > > 采用CRC校验后，数据链路层的传输是否就变成了可靠的传输？ P(X)=X^4 + X + 1 --> 10000+10+1=10011 ![image-20220428172848311](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281728361.png) **除数5位，被除数添加4【5-1】个0** ![image-20220428172921939](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281729982.png) 除法运算得出的余数，就是添加在**数据后面**的**检验序列** 余数不为0，接收端能够发现 ![image-20220428172949127](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281729167.png) 余数不为0，接收端能够发现 > 3-08 要发送的数据为101110.采用CRC的生成多项式是P(X)=X^3 + 1 。试求应添加在数据后面的余数 1000+1=1001 ![image-20220428173048321](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281730356.png) **除数4位，被除数添加3【4-1】个0** > 3-20 假定1km长的CSMA/CD网络的数据率为1Gbit/s。设信号在网络上的传播速率为200 000 km/s。 > > 求能够使用此协议的最短帧长 端到端的传播时延=（1km）/（200 000km/s）=5 µs 争用期2₹（₹是以太网单程端到端的传播时延） ![image-20220428173144257](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281731285.png) \=L/C![img](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAGkAAAARCAIAAABRkRXBAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAHrSURBVFhHY/z//z/DKCALMEHpUUA6GA078sFo2JEPCIXdrRnmjOjAaf4DqCyl4O4cG8bC/VDOkAMEwu7l+f3c069+////ZIOoevfF//9/7cpiN1FWgEoTAgTC5u7+BQyzcxyhPAaG/YXQ2AGCIRCkBMJOPHzlvgwtDoa7l3Z/8jPTY2BgVTLM05SDylII9k9JZUhwVIZwQMHsdHr2HWC9Dwb9iCAdtADqVPzg4+ZYhtjNH6E84sGd2dYMBfugHHSwrwBJDq/KQQqIqit+n927ytFRhw/KxQSgRIMCCOe4u3NqTyPl10dXj1prUyk90wsQFXbXz25X8DLGU8gppxyBxgUUEMxxKPkVGJJ3T0NZQwgQE3YPzm574GmsCeUBwbvjbQ5iHIwcYv7zb/0GCZCc7vZvmlDQnAIPOgZlZVOGo1cfQXlDBUATCm7w68F8Twaz6TehXCC4OlHXevrNX79erotlx18K4ijFgMLWiFoBAkBKh1iJRzDswH4CAoRn789zBDdXwHJQFg4A0wwF0KABVhIYQQcCKKqHQDASV8+iABLCDhsAhdBQq1GxA6LqClSgoG3/bsPBaz9+v7p06JKNNrHtZBgA1StDofFGBICGIUng7b5KbV4GBl7thBU3f0HFRiAYHb8jFzAwAAB5jUgM9WiGlQAAAABJRU5ErkJggg==) **帧长单位Mbit/s** 要发送（1Gbit/s）\*（10µs）=10000 bit 最短帧长10000bit，或1250字节 > 3-33 在图中，以太网交换机有6个接口，分别接到5台主机和一个路由器 > > ![image-20220428173218068](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281732476.png) > > 在下面表的"动作"一栏中，表示先后发送了4个帧。假定在开始时，以太网交换机的交换表是空的。 > > 试把该表中其他的栏目都填写完。 ![image-20220428173334212](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281733247.png) **第4章** > 4-05 IP地址分为几类？各如何表示？IP地址的主要特点是什么？ IP地址共分为5类 **全0全1除外** A类：**1**.0.0.0 ~ **126**.0.0.0 B类：**128**.0.0.0 ~ **191**.255.255.255 C类：**192**.0.0.0 ~ **223**.255.255.255 D类：**224**.0.0.0 ~ **239**.255.255.255 E类：**240**.0.0.0 ~ **255**.255.255.255 **主要特点** （1）IP地址是标志一个主机和一条链路的接口 （2）每个IP地址由网络号和主机号组成 （3）不同网络号的局域网必须使用路由器互连 （4）在IP地址中，所有分配到网络号的网络都是平等的 > 4-17 一个3200位长的TCP报文传到IP层，加上160位的首部后成为数据报。 > > 下面的互联网由两个局域网通过路由器连接起来，但第二个局域网所能传送的最长数据帧中的数据部分 > > 只有1200位，因此数据报在路由器必须进行分片。试问第二个局域网向其上层要传送多少比特的数据？ IP数据报的总长度-IP数据报的首部=1200-160=1040 bit TCP交给IP的数据3200 bit=1040+1040+1040+80，必须划分**4**个数据报片 4个数据报片的总长度=1200+1200+1200+240=3840 bit > 4-22 一个数据报长度为4000字节（固定首部长度）。现在经过一个网络传送，但此网络能够传送的最大数据长度为1500字节。试问应当划分为几个短些的数据报片？各数据报片的数据字段长度、片偏移字段和MF标志为何数值？ 数据报总长度减去首部长度，得出IP数据报的数据部分长度=4000-**20**=3980 B 划分一个数据报片的长度=1500-20=1480 B 3980=1480+1480+1020 应当划分3个数据报片 | 3个数据报片 | 数据字段长度 | 总长度 | 片偏移字段 | MF标志 | | ----------- | ------------ | ------ | ----------------- | ------ | | 原始数据报 | 3980 | 4000 | **0** | 0 | | 1 | 1480 | 1500 | **0**(0/8) | 1 | | 2 | 1480 | 1500 | **185**(1480/8) | 1 | | 3 | 1020 | 1040 | **370**(2\*1480/8) | 0 | > 4-41 假定网络中的路由器B的路由表由如下的项目（"目的网络"，"距离"，"下一跳路由器"） ![image-20220428173813159](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281738196.png) 现在B收到从C发来的路由信息（'目的网络'，'距离'） ![image-20220428173838572](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281738606.png) 试求出路由器B更新后的路由表（详细说明步骤） **修改从C发来的路由表 跳数+1** | ![img](data:image/png;base64,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) | 5 | | ------------------------------------------------------------ | ---- | | ![img](data:image/png;base64,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) | 9 | | ![img](data:image/png;base64,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) | 5 | | ![img](data:image/png;base64,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) | 4 | | ![img](data:image/png;base64,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) | 6 | **下一跳改为C** | ![img](data:image/png;base64,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) | 7 | C | 无新信息，不更新 | | ------------------------------------------------------------ | ---- | ---- | -------------------------------- | | ![img](data:image/png;base64,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) | 5 | C | 相同的下一跳，更新 | | ![img](data:image/png;base64,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) | 9 | C | 新项目，添加 | | ![img](data:image/png;base64,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) | 5 | C | 不同的下一跳，距离更短，更新 | | ![img](data:image/png;base64,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) | 4 | E | 不同的下一跳，距离一样，不更新 | | ![img](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAADoAAAARCAIAAAADsiiKAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAFqSURBVEhLY/z//z/D0AFMUHqIgFHn0hIQ49z9hYxAoDfpGpj3cmUgiGsz5y6YS2cAzGoEwc3pqVlZ1taz78C4Zp7zH/yCcOgLiEoMH16KBaQEvFmwHxKgL+5xB9nKs4LZdAbEOPfWuQ/KqoZ2kbcg7r106pi9njJEit6ACOe+PH9aQFuBwcwz+9a6E08ZXl4/qm9lCJWjNyDs3E+nt3KAnWfolnZm6YGH1058N1EdkJQABISde+PsT4jzWE28086smb33uYuxAkji3fE2BzEORkY+nar970AC9ADQLIcL/DpWLZq1C1oK/NpXwMvODuGC2LHrXv76//3qJGvRhpMQFbQGBEJ3f5lV6+tpbmX7wTxWG79kBk87PVBYf//69hcDKwsrA7OsotbrD1/BCmgPoM4mHXw82WXBy8DAq+3jqEq30CXfuWDw69Oj493u7vOgFQjNAUXOPVjKK2qYMPvcWyif9mBItXcZGACJMIrHKnEZ3QAAAABJRU5ErkJggg==) | 4 | F | 不同的的下一跳，距离更大，不更新 | > 4-42 假定网络中的路由器A的路由表有如下的项目 > > ![image-20220428174014893](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281740930.png) > > 现在收到从C发来的路由信息 > > ![image-20220428174029044](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281740079.png) > > 试求出路由器A更新后的路由表（详细说明步骤） 跳数加1 | ![img](data:image/png;base64,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) | 3 | | ------------------------------------------------------------ | ---- | | ![img](data:image/png;base64,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) | 2 | | ![img](data:image/png;base64,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) | 4 | | ![img](data:image/png;base64,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) | 8 | 下一跳改为C | ![img](data:image/png;base64,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) | 3 | C | 不同的下一跳，距离更短，更新 | | ------------------------------------------------------------ | ---- | ---- | ------------------------------ | | ![img](data:image/png;base64,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) | 2 | C | 相同的下一跳，距离相等，不更新 | | ![img](data:image/png;base64,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) | 1 | F | 不同的下一跳，距离更大，不更新 | | ![img](data:image/png;base64,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) | 5 | G | 不同的下一跳，距离更大，不更新 | 分组转发算法（**传统分类IP地址**）【p134】 ![image-20220428174226147](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281742190.png) **划分子网**下的分组转发算法【p140】 ![image-20220428174242500](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281742546.png) （3）RIP/OSPF【p154，159】 **RIP**协议的特点\*\*： （1）\*\*仅和相邻路由器交换信息 （2）路由器交换的信息是**当前自己的路由表** （3）**按固定的时间间隔**交换路由信息 **距离向量算法** （1）对地址为X的相邻路由器发送过来的RIP报文 修改"**下一跳**"字段的地址为X 所有的"**距离**"字段的值加1 （2）对修改后的RIP报文中的每一个项目 若原来的路由表中没有目的网络N，则添加到路由表； 否则，若下一跳路由器地址是X，则替换原来的项目； 否则，若收到的项目中的距离d小于路由表中的距离，则更新； 否则什么都不做 **OSPF**协议的基本特点： （1)使用洪泛法向本自治系统中**所有路由器**发送信息 （2）发送的信息是与本路由器**相邻的所有路由器的链路状态** （3）只有当链路状态**发生变化**时，路由器才向所有路由器用洪泛法发送此信息 **划分子网** 1、网络192.168.40.0是C类网络 ​ 子网划分只能从第4个字节开始 设子网位为nbit,2^n-2>=6 n合适的取值为3，即将第4个字节的高3位用于子网位0 子网掩码是一个32bit的二进制，其中为1的位表示网络位或子网位，为0的位表示主机位 子网掩码=255.255.255.11100000=255.255.255.224 2、2^(8-3)-2=30 每个子网可分配主机30个 3、第1子网ID=192.168.40.00100000=192.168.40.32 可分配IP地址范围： 192.168.40.00100001-192.168.40.00111110 即192.168.40.33-192.168.40.62 第2子网ID=192.168.40.01000000=192.168.40.64 可分配IP地址范围： 192.168.40.01000001-192.168.40.01011110 即192.168.40.65-192.168.40.94 .. 第3子网ID=192.168.40.96 可分配IP地址范围：192.168.40.97-126 **第5章** > 5-13 一个UDP用户数据报的数据字段为8192字节。在链路层要使用以太网来传送。试问应当划分为几个IP数据报片？说明每一个IP数据报片的数据字段长度和片偏移字段的值 UDP用户数据报长度=8192+**8**=8200 B IP数据报的数据部分=UDP首部+UDP用户数据报的数据部分 以太网数据字段最大长度为1500 B 划分的IP数据报的数据部分=1500-20=1480 B 8200=1480\*5+800 应当划分6个IP数据报片 | 6个数据报片 | 数据字段长度 | 总长度 | 片偏移字段 | | ----------- | ------------ | ------ | ----------------- | | 原始数据报 | 8192 | 8200 | **0** | | 1 | 1480 | 1500 | **0**(0/8) | | 2 | 1480 | 1500 | **185**(1480/8) | | 3 | 1480 | 1500 | **370**(2*1480/8) | | 4 | 1480 | 1500 | **555**(3*1480/8) | | 5 | 1480 | 1500 | **740**(4*1480/8) | | 6 | 800 | 820 | **925**(5*1480/8) | ## 网课习题 ### **第一章--概述** 1、在我国第一个实现IPv6的网络是（ ）。A.CHINANet B.EDUNet C.**CERNET2** D.UNINET 2、因特网起源于（ ）网络。 **&&** 互联网起源于（ ）网络。A.**ARPANET** B.Ethernet C. CATV D.CERNET 3、人们把（ ）年作为因特网的诞生时间。A.1969 B.**1983** C.1985 D.1993 4、中国目前最大的ISP是（ ）。A.中国移动B.中国联通 C.**中国电信** D.中国网通 5、在互联网的标准化中，负责近期工程技术研究的是( ）A.ISO B.IRTF C.**IETF** D.IAB 6、所有的RFC最终都将成为（ ）A.互联网标准 B.**历史的\*\*\*\*RFC** C.建议标准D.ISO标准 7、中国教育和科研计算机网简称为（ ）A.CHINANET B.EDUNET C.**CERNET** D.UNINET 8、我国在（ ）年正式接入互联网，并被国际承认。A.1980 B.1989 C.**1994** D.1997 9、目前负责中国互联网相关管理工作的机构是（ ）。A.工信部 B.**CNNIC** C.CERNET D.邮电部 10、我国第一个公用分组交换网 CNPAC 在（ ）年建成运行。A.1980 B.**1989** C.1994 D.1997 11、从网络的作用范围进行分类，网络可以分为PAN、LAN、（ ）、WAN。A.**城域网** B.广域网 C.局域网 D.个人区域网 12、从作用范围来分，校园网属于（ ）。A.**LAN** B.MAN C.WAN D.PAN 13、ISO提出的网络体系结构是（ ）。A.**OSI** B.TCP/IP C.SNA D.IEEE 14、目前互联网上使用的事实上的国际标准是（ ）。A.OSI B.**TCP/IP** C.SNA D.IEEE ![image-20220428174634100](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281746157.png) ### 第二章--物理层 ![image-20220428175007627](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281750710.png) ### **第三章--数据链路层** 1. PPP帧的标志字段等于0x（ ）A.80 B.**7e** C.ff D.88 2. 数据链路层封装的PDU称为( )A.分组 B.**帧** C.报文 D.比特流 3. 数据链路除了物理线路外，还必须有（ ）来控制这些数据的传输。A.软件 B.逻辑链路 C.**通信协议** D.网卡 4. 数据链路层的帧中封装的数据一般为上一层的（ ）A.**分组** B.帧C.报文D.比特流 5. 数据链路层协议需要解决的三个基本问题是封装成帧、透明传输与（ ）A.加密技术B.身份验证C.可靠机制 D.**差错控制** 6. 数据链路层中使用最为广泛的检错技术是（ ）A.海明码检验 B.**循环冗余检验** C.奇偶检验 D.公钥加密 7. 某CRC生成多项式P有n位，则其冗余码应该是（ ）位。A.**n-1** B.n C.n+1 D.32 8. PPP帧的标志字段等于0x（ ）。A.80 B.7e C.ff D.88 9. 在目前的局域网中，（ ）拓扑最为常见。 A.**星形** B.总线C.环形D.网状 10. 世界上第一个以太网的规约是（ ）。A.**DIX Ethernet V2** B.IEEE 802.3 C.OSI/RM D.TCP/IP 11. 10BASE-T中的T表示使用的传输媒体是（ ）。A.粗同轴电缆 B.细同轴电缆 C.**双绞线** D.光缆 12. 10BASE-T中的BASE表示（ ）。A.**基带信号** B.宽带信号C.基本速率D.原始以太网 13. 理想情况下以太网的极限信道利用率为（ ）。A.a/(1+a) B.**1/(1+a)** C.1/a D.(a+1)/a 14. 以太网帧格式规定，其数据部分最长为（ ）字节。A.64 B.128C.1000 D.**1500** 15. 使用双绞线组建以太网时，其网线最大长度为（ ）米。A.10 B.50 C.64 D.**100** 16. 当以太网的连接距离超过100米时，在物理层上扩展范围最好的方法是使用（ ）。A.双绞线 B.**光缆** C.同轴电缆 D.无线电 17. 目前在数据链路层扩展局域网是使用（ ）设备。A.集线器B.转发器C.路由器 D.**交换机** 18. 当以太网出现环路时，可以使用（ ）协议避免广播风暴的出现。A.CSMA/CD B.**STP** C.CRC D.FTTx 19. 100 BASE-T 以太网的最短帧长为（ ）字节。A.32 B.48 C.**64** D.128 20. 1000 BASE-T要求使用的双绞线必须是（ ）类线以上。A.3 B.4 C.**5** D.超5 21. 10 GBASE-T以太网中使用的双绞线必须是（ ）类线以上。A.5 B.5E C.6 D.**6A** 22. **MAC**地址共定义有（**48**）**bit** 23. 用户使用拨号电话线与Modem接入因特网时，一般都是使用（ ）协议。A.ISP B.**PPP** C.PPPOE D.CSMA/CD ![image-20220428175157990](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281751066.png) ### **第四章--网络层** 1、下列协议属于网际层的是（）A.**ICMP** B.CSMA/CD C.TCP D.HTTP 2、IP 地址的编址方法有（**3**）种。 3、IP地址211.85.1.122属于（**C**）类IP地址。 4、IP地址表示合法的是（）。A.256.123.9.1 B.0.127.1.0 C.**192.168.40.100** D.200.3.6 5、MAC地址共有（**48** ）bit。 6、IP 地址是 141.14.72.24，子网掩码是 255.255.192.0，其网络地址为（）A.**141.14.64.0** B.141.14.52.0 C.141.14.32.0 D.141.14.128.0 **IP\*\*\*\*地址和子网掩码**都换算成二进制,然后进行与运算(1和1为1，其余都为0) 7、B类IP地址默认的子网掩码为（ ）A.255.0.0.0 B.**255.255.0.0** C.255.255.255.0 D.255.255.255.255 8、相对分类的IP地址而言，在划分子网的情况下，路由表项将增加（ ）内容。A.下一跳 B.目的网络地址C.子网掩码D.生存时间 9、CIDR地址192.168.40.0/22的掩码为（ ）。A.255.255.0.0 B.**255.255.252.0** C.255.255.255.0 D.255.255.255.255 **22**代表**22**位为子网位或者网络位，**32-22=10**位为主机位，11111111.11111111.11111100.00000000(255.255.252.0) 10、CIDR记法中，10/10表示的掩码为（ ）。A.255.0.0.0 B.**255.192.0.0** C.255.255.0.0 D.255.255.255.0 **11111111.11**000000.0.0(255.192.0.0) 11.互联网有两大类路由选择协议：IGP与（ ）A.**EGP** B.RIP C.OSPF D.ARP 12.内部网关协议 IGP有多种，最常见的有OSPF与（ ）A.EGP B.**RIP** C.OSPF D.ARP 13.外部网关协议中目前使用**最多**的是（ ）A.EGP B.IGRP C.EIGRP **D.BGP-4** 14.内部网关协议 IGP 中最先得到**广泛**使用的协议是（ ）A.EGP **B.RIP** C.OSPF D.ARP 15.RIP认为不可达网络的距离为（ **16** ）。 16.整个的路由器结构可划分为两大部分：路由选择部分与（ ）部分。A.**分组转发** B.地址缓存 C.转发表D.路由表 17.BGP协议中，每一个自治系统中至少要选择一个路由器作为该自治系统的（ ）。A.管理员B.**发言人** C.代理D.缓存结点 18.路由器是（ ）层设备。A.物理B.数据链路 C.**网络** D.传输 19.RFC 1918定义的第2个地址块前缀为（ ）位。A.8 B.**12** C.16 D.24 20.内部主机与外部主机通信时，在NAT路由器上发生了（**2** ）次地址转换。 21.某主机在发送IP分组时，需要首先使用（）的子网掩码计算目标IP地址对应的网络地址。A.目的主机 B.**本机** C.路由器D.交换机 22.RIP 允许一条路径最多只能包含 （ **15** ）个路由器。 23.BGP中，用来与相邻的另一个BGP发言人建立关系的报文是（ ）。A.**打开报文**B.更新报文C.保活报文D.通知报文 ![image-20220428175322040](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281753105.png) ![image-20220428175333955](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281753012.png) ### 第五章--运输层 1.用户提出服务请求,网络将用户请求传送到服务器;服务器执行用户请求,完成所要求的操作并将结果送回用户,这种工作模式称为（ ） **A.客户服务器模式** B.点到点模式 C.SMA/CD模式 D.令牌环模式 2. 应用层的各种进程通过（ ）实现与运输实体的交互 A.程序 **B.端口** C.进程 D.调用 3.熟知端口的范围是（ ） A.0～99 **B.0～1023** C.0～255 D.0～65535 满分：4.00 分 得分：4.00 分 4.欲保证一个报文可靠、无差错的传输到接收端，下列哪种说法正确（ ） **A.TCP最适合** B.UDP 最适合 C.两个都可以 D.不能比较 满分：4.00 分 得分：4.00 分 5.下述的哪一种协议是不属于TCP/IP模型的协议（ ） A.TCP B.UDP C.ICMP **D.HDLC** 6. UDP 协议校验的数据是（ ） A.首部＋伪首部 B.首部 **C.首部＋数据** D.伪首部＋数据 7. UDP中伪首部中的IP地址内容和编排顺序是（ ） A.只有源IP地址 B.只有目的IP地址 **C.源IP地址＋目的IP地址** D.目的IP地址+源IP地址 满分：4.00 分 得分：4.00 分 8.TCP 的主要功能是（ ） A.进行数据分组 **B.保证可靠传输** C.确定数据传输路径 D.提高传输速度 满分：4.00 分 得分：4.00 分 9.TCP报文中确认序号指的是 （ ） A.已经收到的最后一个数据序号 **B.期望收到的第一个字节序号** C.出现错误的数据序号 D.请求重传的数据序号 满分：4.00 分 得分：4.00 分 10.（ ）的功能不属于TCP协议的职责 A.端到端的流量控制 B.重传出错或被丢弃的数据 C.识别接收次序与发送次序不同的数据 **D.发现网络错误时候报告网络错误** 11.在TCP/IP参考模型中,运输层的主要作用是在互联网络的源主机和目的主机对等实体之间建立用于会话的（ ）。 A.物理连接 B.操作连接 **C.端到端连接** D.控制连接 12.下列不属于通信子网的是（ ） A.物理层 B.数据链路层 C.网络层 **D.运输层** 13.可靠的传输协议中的“可靠”指的是（ ） A.使用面向连接的会话 B.使用“尽力而为”的传输 C.用滑动窗口来维持可靠性 **D.使用确认机制来确保传输的数据不丢失** 14.在 TCP/IP 参考模型中TCP协议工作在：（ ） A.应用层 **B.运输层** C.互连层 D.主机-网络层 满分：4.00 分 得分：4.00 分 15.TCP报文段中**序号字段**指的是（ ） **A.数据部分第一个字节** B.数据部分最后一个字节 C.报文首部第一个字节 D.报文最后一个字节 16.TCP报文中**确认序号**指的是（ ） A.已经收到的最后一个数据序号 **B.期望收到的第一个字节序号** C.出现错误的数据序号 D.请求重传的数据序号 17.TCP报文的首部最小长度是（ 20 ）字节。 18.TCP的确认是对接收到的数据中（ ） 表示确认 **A.最高序号** B.第一个序号 C.第二个序号 D.倒数第二个序号 19.TCP协议是采用（ ）进行编号的 A.按报文段 **B.字节** C.数据帧 D.IP数据报 满分：4.00 分 得分：4.00 分 20.TCP采用（ ）的方式进行流量控制 **A.可变发送窗口** B.固定发送窗口 C.固定接收窗口 D.以上都不是 ![image-20220428175608565](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281756617.png) ### **第六章--应用层** 1.在互联网上共有（ **13** ）个不同的根域名服务器 2.FTP进行控制连接时使用的默认端口号为( **21** ) 3.FTP进行数据连接时使用的默认端口号为（**20**） 4.使用（ **URL** ）来标志万维网上的各种文档 5.（ **URL** ）是互联网资源的位置表示形式 6.目前互联网中使用最多的URL协议是（**HTTP**） 7.万维网站点使用（ **Cookie** ）来跟踪用户 8.通过（ **DHCP** ）协议可以在网络中动态地获得IP地址 9.有关网络域名系统的描述中，不正确的是（ ） A.网络域名系统的缩写为DNS B.每个域名可以由几个域组成，域与域之间用"."分开 C.**域名中的最左端的域称为顶级域** D.cn是常用的顶级域名代码 10.系统对WWW 网页存储的默认格式是( HTML ) ![image-20220428175635895](https://note-1259190304.cos.ap-chengdu.myqcloud.com/note/202204281756953.png)