1 00:00:00,000 --> 00:00:04,580 2 00:00:04,580 --> 00:00:06,580 DOUG LLOYD: Kama wameweza wamekuwa kuangalia video hizi 3 00:00:06,580 --> 00:00:09,030 ili na sisi kupendekeza, sisi ni juu ya kufanyiwa 4 00:00:09,030 --> 00:00:10,260 kidogo ya mabadiliko utamaduni. 5 00:00:10,260 --> 00:00:13,093 Kwa sababu sasa, sisi ni kwenda kuanza kuzungumza juu ya biashara na mtandao 6 00:00:13,093 --> 00:00:13,669 teknolojia. 7 00:00:13,669 --> 00:00:15,835 Hivyo hadi sasa, tumekuwa kweli wamekuwa wakifanya mengi ya C. 8 00:00:15,835 --> 00:00:17,370 >> Na wakati sisi tumekuwa kuendesha programu yetu, 9 00:00:17,370 --> 00:00:19,500 tumekuwa mbio yao kutoka mstari amri. 10 00:00:19,500 --> 00:00:23,080 Hiyo ni pretty kiasi gani watumiaji kuwa wamekuwa mazungumzo na mipango 11 00:00:23,080 --> 00:00:23,760 kwamba sisi kuandika. 12 00:00:23,760 --> 00:00:26,859 Wao kuchukua kitu kuchochea, kitu hutokea katika dirisha terminal, 13 00:00:26,859 --> 00:00:27,650 na kisha ni kosa. 14 00:00:27,650 --> 00:00:30,957 >> Wakati mwingine unaweza kuwa na kuendelea data kwamba bado baadaye. 15 00:00:30,957 --> 00:00:32,040 Lakini hiyo ni pretty kiasi. 16 00:00:32,040 --> 00:00:33,081 Ni katika mstari amri. 17 00:00:33,081 --> 00:00:34,775 Ni njia pekee mtumiaji anaweza kuingiliana. 18 00:00:34,775 --> 00:00:36,650 Kutokana na hatua hii mbele, sisi ni kwenda kuanza 19 00:00:36,650 --> 00:00:39,980 transitioning ili watumiaji unaweza kuingiliana na tovuti yetu. 20 00:00:39,980 --> 00:00:42,688 Hivyo sisi ni kwenda kuwa kuandika tovuti, ambazo hazikuandikwa katika C, 21 00:00:42,688 --> 00:00:46,600 lakini majina yao yameandikwa aina ya wengine lugha ya programu, ikiwa ni pamoja na PHP, 22 00:00:46,600 --> 00:00:50,810 na ni aina ya lugha msaidizi, HTML, CSS, na kadhalika. 23 00:00:50,810 --> 00:00:53,130 Hivyo sisi ni kwenda kuanza kuzungumza juu ya mambo hayo. 24 00:00:53,130 --> 00:00:55,740 >> Kabla ya kuingia katika mtandao programu yenyewe, 25 00:00:55,740 --> 00:00:58,720 Nadhani ni pengine vizuri Wazo kuchukua hatua nyuma na majadiliano 26 00:00:58,720 --> 00:01:02,720 kuhusu jinsi kompyuta na binadamu kiutendaji juu ya mtandao. 27 00:01:02,720 --> 00:01:07,520 Hivyo video hii ni kweli utangulizi, mwongozo wa msingi, na mtandao. 28 00:01:07,520 --> 00:01:10,951 Sasa, caveat hapa ni CS50 sio mitandao darasani. 29 00:01:10,951 --> 00:01:13,700 Hivyo nini tunakwenda kuwa kuzungumza kuhusu hapa ni kiwango cha pretty juu. 30 00:01:13,700 --> 00:01:17,240 Sisi siyo kwenda kwa kupata katika ngazi yoyote chini 31 00:01:17,240 --> 00:01:19,540 maelezo ya jinsi mambo haya yote kazi. 32 00:01:19,540 --> 00:01:21,290 Kama wewe ni nia kwa kuwa, ningependa sana 33 00:01:21,290 --> 00:01:24,580 kupendekeza kuchukua darasa juu ya mitandao ya kompyuta. 34 00:01:24,580 --> 00:01:26,540 Na tupate hata kuwaambia uongo nyeupe au mbili tu 35 00:01:26,540 --> 00:01:31,590 kwa madhumuni ya kujipatia uelewa wa jumla wa wazi. 36 00:01:31,590 --> 00:01:35,780 >> Hivyo kwa kuwa alisema, hebu majadiliano juu ya jinsi sisi kiutendaji na mtandao. 37 00:01:35,780 --> 00:01:37,570 Hivyo hapa sisi ni. 38 00:01:37,570 --> 00:01:38,430 Hapa ni yetu. 39 00:01:38,430 --> 00:01:41,096 Sisi ni pretty kuangalia mbele kwa kupata kwenye mtandao, ambayo 40 00:01:41,096 --> 00:01:42,810 kama sisi wote tunajua, ni chock kamili ya paka. 41 00:01:42,810 --> 00:01:45,210 >> Sasa sisi tu kuungana na biashara kama hii? 42 00:01:45,210 --> 00:01:46,360 Naam, pengine si. 43 00:01:46,360 --> 00:01:48,620 Shirikishi, unajua kwamba, kusema kwa mfano, 44 00:01:48,620 --> 00:01:51,190 wakati mabadiliko yako Wi-Fi mtandao kwenye kompyuta yako, 45 00:01:51,190 --> 00:01:54,010 huna kuona mtu mmoja aitwaye biashara isipokuwa kwamba tu hivyo hutokea 46 00:01:54,010 --> 00:01:58,870 kuwa jina la eneo lako Wi-Fi. 47 00:01:58,870 --> 00:01:59,370 Sawa? 48 00:01:59,370 --> 00:02:00,880 >> Ni kawaida kitu kama nyumbani. 49 00:02:00,880 --> 00:02:03,338 Au kama wewe ni katika kazi, inaweza jina la kampuni yako. 50 00:02:03,338 --> 00:02:05,340 Kuna si moja tu chaguo aitwaye mtandao. 51 00:02:05,340 --> 00:02:09,710 Na hivyo kitu au baadhi mambo zipo katika kati ya wakati 52 00:02:09,710 --> 00:02:11,490 tunataka kuungana na mtandao. 53 00:02:11,490 --> 00:02:12,740 Je, ni baadhi ya mambo hayo? 54 00:02:12,740 --> 00:02:14,110 Naam, sisi ni kwenda kuzungumza kuhusu hilo. 55 00:02:14,110 --> 00:02:16,180 Sisi ni pia kwenda kuzungumza kuhusu baadhi ya mambo muhimu 56 00:02:16,180 --> 00:02:18,710 tunahitaji ili kuweza kuunganisha na mtandao. 57 00:02:18,710 --> 00:02:21,214 Na ya kwanza ya haya mambo ni anwani ya IP. 58 00:02:21,214 --> 00:02:23,380 Hivyo wameweza pengine habari IP mrefu kabla. 59 00:02:23,380 --> 00:02:24,630 Ina maana gani? 60 00:02:24,630 --> 00:02:28,270 Naam, IP ni kimsingi kitambulisho kipekee 61 00:02:28,270 --> 00:02:30,820 ya kompyuta yako kwenye mtandao. 62 00:02:30,820 --> 00:02:33,640 Tu kama kila nyumba au Ofisi ina anwani kipekee 63 00:02:33,640 --> 00:02:36,660 ambayo mtu anaweza kutuma barua. 64 00:02:36,660 --> 00:02:40,750 >> Vile vile, kila kompyuta ikiwa ni anataka kupokea data au kutuma data, 65 00:02:40,750 --> 00:02:43,040 anahitaji kuwa na anwani ya kipekee. 66 00:02:43,040 --> 00:02:45,720 Hivyo kwamba wakati habari ni alimtuma au kupokea, 67 00:02:45,720 --> 00:02:49,720 ni kuwa ametumwa kutoka au kupokea eneo sahihi. 68 00:02:49,720 --> 00:02:52,660 Mpango huu kushughulikia, kama mimi Alisema, inaitwa IP kushughulikia. 69 00:02:52,660 --> 00:02:57,690 IP ni anasimama kwa Itifaki ya Internet, ambayo tutaweza majadiliano juu tena hivi karibuni. 70 00:02:57,690 --> 00:03:00,230 >> Sasa, je IP kushughulikia kuangalia kama? 71 00:03:00,230 --> 00:03:04,330 Naam, mpango kimsingi alikuwa, wakati ilikuwa ya kwanza kutekelezwa, 72 00:03:04,330 --> 00:03:07,846 kutoa kila kompyuta kipekee 32-bit mahali. 73 00:03:07,846 --> 00:03:08,720 Kwamba mengi ya vipande. 74 00:03:08,720 --> 00:03:10,900 Hiyo ni anwani za bilioni 4. 75 00:03:10,900 --> 00:03:14,190 >> Na kwa ujumla, badala ya kutumia nukuu hexadecimal, ambayo 76 00:03:14,190 --> 00:03:18,450 tumekuwa kutumika hapo awali katika mazingira ya kuyatumia katika C kuzungumzia anwani, 77 00:03:18,450 --> 00:03:21,580 sisi kwa kawaida kuwakilisha IP anwani katika kidogo zaidi 78 00:03:21,580 --> 00:03:24,370 ya kirafiki binadamu njia, anayewakilisha yao 79 00:03:24,370 --> 00:03:28,680 kama nguzo nne za bits 8 kuwakilishwa kama idadi decimal. 80 00:03:28,680 --> 00:03:34,920 Kwa sababu wanadamu hawana mara nyingi kusema hexadecimal, kama wewe ni programu. 81 00:03:34,920 --> 00:03:38,400 Lakini watu ambao wanatumia biashara si programmers lazima. 82 00:03:38,400 --> 00:03:41,660 >> Na hivyo kufanya kuwa rahisi na kupatikana kwa ajili yao 83 00:03:41,660 --> 00:03:45,430 kuwa na uwezo wa kuzungumza kuhusu nini wao IP ni katika kesi wao labda 84 00:03:45,430 --> 00:03:47,690 haja ya kuwaita na mtu troubleshoot kitu, 85 00:03:47,690 --> 00:03:51,610 ni bora kufanya hivyo katika zaidi kawaida kawaida idadi alisema 86 00:03:51,610 --> 00:03:52,880 format. 87 00:03:52,880 --> 00:03:57,570 Na hivyo IP tu inaonekana pretty kiasi kama hii, w.x.y.z, 88 00:03:57,570 --> 00:04:00,650 ambapo kila moja ya barua hizo inawakilisha thamani mashirika yasiyo ya hasi 89 00:04:00,650 --> 00:04:02,960 katika aina mbalimbali ya 0-255. 90 00:04:02,960 --> 00:04:07,950 Kumbuka kwamba 8-bit idadi wanaweza kushikilia maadili 256 tofauti. 91 00:04:07,950 --> 00:04:10,520 >> Na hivyo ndiyo sababu mbalimbali wetu ni 0 hadi 255. 92 00:04:10,520 --> 00:04:15,030 Na tuna makundi manne ya 8 bits kwa jumla kuu ya 32 bits. 93 00:04:15,030 --> 00:04:17,920 Na hivyo IP nguvu kuangalia kitu kama hii. 94 00:04:17,920 --> 00:04:24,120 Hii ni aina ya kurefusha maisha chaguo-msingi IP, 123.45.67.89. 95 00:04:24,120 --> 00:04:28,850 Wote ni katika aina mbalimbali ya 0 kwa 255, hivyo hiyo ni anwani ya IP halali. 96 00:04:28,850 --> 00:04:34,040 >> Hapa katika Chuo Kikuu cha Harvard, wote wa IP yetu kuanza na 140.247. 97 00:04:34,040 --> 00:04:37,130 Hiyo ni njia tu kwamba IP anwani katika eneo hili kijiografia 98 00:04:37,130 --> 00:04:38,130 kuwa alipewa. 99 00:04:38,130 --> 00:04:42,750 Na hivyo hii inaweza kuwa IP kwamba yanaweza kuwepo hapa katika Harvard. 100 00:04:42,750 --> 00:04:46,810 >> Hivyo kama nilivyosema, ikiwa kila IP ni 32 bits, tuna kuhusu bilioni 4 101 00:04:46,810 --> 00:04:49,290 kutoa nje, kidogo zaidi ya bilioni 4. 102 00:04:49,290 --> 00:04:51,470 Lakini tunaweza aina ya kuona tatizo, sawa? 103 00:04:51,470 --> 00:04:53,190 Nini idadi ya watu duniani sasa hivi? 104 00:04:53,190 --> 00:04:56,560 >> Naam, ni mahali fulani kaskazini mwa watu bilioni 7. 105 00:04:56,560 --> 00:04:58,800 Na katika dunia ya Magharibi angalau, watu wengi 106 00:04:58,800 --> 00:05:02,644 na kifaa zaidi ya moja uwezo wa kuunganishwa mtandao. 107 00:05:02,644 --> 00:05:03,560 Nina moja hapa hapa. 108 00:05:03,560 --> 00:05:04,880 Na mimi na mwingine mmoja katika mfuko wangu. 109 00:05:04,880 --> 00:05:06,340 Na mimi kuwa moja nyuma katika ofisi yangu. 110 00:05:06,340 --> 00:05:07,387 >> Na hivyo ndiyo tatu. 111 00:05:07,387 --> 00:05:09,970 Na kwamba hana hata kuhesabu wale ambao nina nyumbani, pia. 112 00:05:09,970 --> 00:05:12,160 Na hivyo hiyo ni aina ya tatizo, sawa? 113 00:05:12,160 --> 00:05:15,380 Tuna watu wasiopungua bilioni 7 na anwani bilioni 4 tu. 114 00:05:15,380 --> 00:05:18,719 >> Na kila kifaa zinatakiwa kwa kuwa ya kipekee kutambuliwa. 115 00:05:18,719 --> 00:05:21,260 Tumeanzisha baadhi workarounds kukabiliana na tatizo hili, 116 00:05:21,260 --> 00:05:23,240 kitu kinachoitwa binafsi IP, ambayo sisi siyo 117 00:05:23,240 --> 00:05:24,573 kwenda kupata katika katika video hii. 118 00:05:24,573 --> 00:05:31,920 Lakini kimsingi, inaruhusu zaidi mtandao, mtandao, kwa namna ya bandia 119 00:05:31,920 --> 00:05:35,610 nje kidogo kwamba una kipekee anuani kwa kuwa na anwani binafsi 120 00:05:35,610 --> 00:05:38,730 na kisha kuelekeza yao kwa njia ya anwani moja moja, ambayo 121 00:05:38,730 --> 00:05:41,220 ni pamoja na kompyuta mbalimbali. 122 00:05:41,220 --> 00:05:43,200 >> Lakini hiyo ni kweli si muda mrefu kurekebisha mrefu. 123 00:05:43,200 --> 00:05:45,250 Hata kuwa fasta si kwenda mara milele. 124 00:05:45,250 --> 00:05:50,030 Na hivyo tunahitaji kuwa na tofauti njia ya kukabiliana na hii. 125 00:05:50,030 --> 00:05:51,904 >> Hivyo kama nilivyosema, tulikuwa kuhusu bilioni 4. 126 00:05:51,904 --> 00:05:53,820 Lakini hiyo si kwenda kuwa nzuri ya kutosha, sawa? 127 00:05:53,820 --> 00:05:56,540 Na hivyo njia ambayo ina imeamuliwa huko tuko 128 00:05:56,540 --> 00:05:59,240 kwenda kukabiliana na hii ni kufanya IP tena. 129 00:05:59,240 --> 00:06:03,344 Badala ya anwani 32-bit, tuko kwenda na anwani 128-bit. 130 00:06:03,344 --> 00:06:05,260 Hivyo badala ya bilioni 4 anwani, tunakwenda 131 00:06:05,260 --> 00:06:11,130 kuwa na kwamba idadi kubwa ya anwani, ambayo ni bilioni 340,000,000,000 bilioni 132 00:06:11,130 --> 00:06:14,150 bilioni, hivyo mengi ya IP. 133 00:06:14,150 --> 00:06:18,240 >> Na mpango huu mpya inaitwa IPv6 ni kawaida ni jinsi gani inajulikana. 134 00:06:18,240 --> 00:06:21,242 Mpango wa miaka kuwa IPv4. 135 00:06:21,242 --> 00:06:23,450 Ni kidogo ya tatizo katika kwamba tatizo hili limekuwa 136 00:06:23,450 --> 00:06:25,470 kujulikana juu kwa kweli kwa muda mrefu. 137 00:06:25,470 --> 00:06:28,025 138 00:06:28,025 --> 00:06:32,201 >> Na utaona hii mengi katika mazingira ya kompyuta na kompyuta. 139 00:06:32,201 --> 00:06:33,700 Tuko vizuri katika unatarajia matatizo. 140 00:06:33,700 --> 00:06:36,449 Lakini sisi ni mbaya wakati wa kushughulika pamoja nao hata kama tunajua kuhusu wao. 141 00:06:36,449 --> 00:06:38,340 Hivyo IPv6 imekuwa karibu kwa muda. 142 00:06:38,340 --> 00:06:40,510 Na tu katika michache ya mwisho Miaka kuwa sisi kweli 143 00:06:40,510 --> 00:06:47,190 kuanza kumalizika katika anwani hizi IPv6 awamu ya nje anwani IPv4. 144 00:06:47,190 --> 00:06:49,520 Lakini baadhi ya maeneo kufanya kuwa nao. 145 00:06:49,520 --> 00:06:52,200 Na wao kuangalia sawa kwa IP mara kwa mara. 146 00:06:52,200 --> 00:06:53,520 Lakini wao ni mengi zaidi. 147 00:06:53,520 --> 00:06:59,900 >> Hivyo badala ya sasa kuwa nne makundi ya 8 ka kwa anwani yako, 148 00:06:59,900 --> 00:07:03,580 sasa tuna nane makundi ya 16 ka. 149 00:07:03,580 --> 00:07:06,680 Na mara 8 16 ni 128. 150 00:07:06,680 --> 00:07:11,210 Na sisi kuwakilisha hizo katika chini kawaida hexadecimal fomu. 151 00:07:11,210 --> 00:07:16,930 Kwa sababu ya kuwa na idadi 16-bit ina maana kwamba badala ya kuwa mbalimbali cha 0 kwa 255, 152 00:07:16,930 --> 00:07:20,350 Tunatarajia kuwa aina mbalimbali ya 0 kwa 65,535. 153 00:07:20,350 --> 00:07:22,470 >> Na hivyo kuwa na rundo wale kukwama kwa pamoja 154 00:07:22,470 --> 00:07:24,680 itakuwa vigumu sana kusoma. 155 00:07:24,680 --> 00:07:27,480 Na hivyo sisi kawaida kutumia hex tu nje ya urahisi. 156 00:07:27,480 --> 00:07:31,180 Na hivyo kawaida anuani IPv6 ili kuangalia kitu kama hiki. 157 00:07:31,180 --> 00:07:35,860 >> Ni hakika mengi kwa muda mrefu kuliko anuani IPv4 tumeona kabla. 158 00:07:35,860 --> 00:07:39,280 Lakini hii itakuwa halali IPv6 mahali. 159 00:07:39,280 --> 00:07:41,570 Hii moja pia ni kuhusu IPv6 mahali. 160 00:07:41,570 --> 00:07:44,331 >> Hii moja kinachotokea kwa mali ya Google. 161 00:07:44,331 --> 00:07:46,080 Na taarifa kuna rundo la zeros huko. 162 00:07:46,080 --> 00:07:47,930 Wakati mwingine anwani hizi wanaweza kupata muda mrefu. 163 00:07:47,930 --> 00:07:50,530 Na kwa kuwa bado tuko pretty mapema katika IPv6, 164 00:07:50,530 --> 00:07:54,250 wakati mwingine kunaweza kuwa na chunks kubwa ya zeros katika pale kwamba hatuna haja. 165 00:07:54,250 --> 00:08:01,920 >> Kama wewe ni kusoma hii kwa sauti kubwa, ni 2001.4860.4860.0.0.0.0.8844. 166 00:08:01,920 --> 00:08:03,325 Ni aina ya mengi, sawa? 167 00:08:03,325 --> 00:08:05,450 Hivyo kama unaweza kuona kundi la zeros, waweza wakati mwingine 168 00:08:05,450 --> 00:08:08,990 kuona anwani IPv6 kama hii, ambako saza zeros 169 00:08:08,990 --> 00:08:10,959 na kutumia matumbo mara mbili badala yake. 170 00:08:10,959 --> 00:08:11,750 Hii ni sawa, ingawa. 171 00:08:11,750 --> 00:08:14,610 Kwa sababu tunajua kwamba kuna watu wanatakiwa kuwa nane chunks tofauti. 172 00:08:14,610 --> 00:08:17,190 Na hivyo kwa maana halisi, tunaona nne. 173 00:08:17,190 --> 00:08:20,620 Hivyo tunajua kwamba lazima kuwe na seti nne ya zeros kama hii, kwamba kujaza katika. 174 00:08:20,620 --> 00:08:23,760 >> Hivyo wakati mwingine, unaweza kuona anuani IPv6 kutokuwa na 175 00:08:23,760 --> 00:08:26,650 chunks nane kutengwa kama sisi kufanya hapa. 176 00:08:26,650 --> 00:08:28,760 Unaweza kuona kuangalia kama hii. 177 00:08:28,760 --> 00:08:31,310 Na kwamba tu ina maana kwamba kila kitu huna kuona katika 178 00:08:31,310 --> 00:08:37,450 kati ya ambapo kwamba matumbo mara mbili ni sifuri tu kutengwa. 179 00:08:37,450 --> 00:08:37,998 >> Hivyo, sawa. 180 00:08:37,998 --> 00:08:40,039 Tunajua kidogo zaidi kuhusu IP sasa. 181 00:08:40,039 --> 00:08:41,250 Lakini jinsi gani sisi kupata yao? 182 00:08:41,250 --> 00:08:44,727 Hatuwezi kuchukua moja tu tunataka. 183 00:08:44,727 --> 00:08:47,810 Kama sisi alifanya hivyo, sisi inaweza kuishia mapigano mtu kwa anwani ya IP huo. 184 00:08:47,810 --> 00:08:50,050 Au mtu anaweza kuwa waliochaguliwa ni hapo awali. 185 00:08:50,050 --> 00:08:52,799 Kama sisi kujaribu na kuchukua hiyo, tunakwenda kukimbia katika kidogo ya tatizo. 186 00:08:52,799 --> 00:08:56,300 Na hivyo hatuwezi tu kuchukua IP kwamba tunataka. 187 00:08:56,300 --> 00:08:58,410 >> Hivyo njia kwamba sisi kupata IP ni mahali fulani 188 00:08:58,410 --> 00:09:02,960 kati ya kompyuta yetu na biashara, kwamba biashara kubwa huko nje, 189 00:09:02,960 --> 00:09:07,500 kuna kitu kinachoitwa DHCP server, Jeshi Nguvu Configuration Itifaki 190 00:09:07,500 --> 00:09:08,630 server. 191 00:09:08,630 --> 00:09:09,960 Ni Mouthful kubwa ya maandishi. 192 00:09:09,960 --> 00:09:12,670 Lakini kwa kweli yote ni gani ni inateua wewe IP. 193 00:09:12,670 --> 00:09:16,960 >> DHCP server yako ina orodha ya anazungumzia iweze kihalali kuwapa. 194 00:09:16,960 --> 00:09:18,160 Na anatoa moja. 195 00:09:18,160 --> 00:09:19,743 Hiyo ni pretty much wote kuna hiyo. 196 00:09:19,743 --> 00:09:23,810 Sasa kabla DHCP, kazi hii ya kumshirikisha anwani 197 00:09:23,810 --> 00:09:25,106 akaanguka msimamizi wa mfumo. 198 00:09:25,106 --> 00:09:27,730 Hivyo mtu halisi ingekuwa manually kuwapa kompyuta yako 199 00:09:27,730 --> 00:09:30,670 na anuani wakati kuunganishwa na mtandao. 200 00:09:30,670 --> 00:09:34,307 Hivyo DHCP tu aina ya automates hii mchakato wa kutoa IP. 201 00:09:34,307 --> 00:09:35,390 Lakini hiyo ni jinsi ya kupata hiyo. 202 00:09:35,390 --> 00:09:37,431 Ni tu mpango mbio mahali fulani kati ya wewe 203 00:09:37,431 --> 00:09:40,920 na biashara ambayo ina benki ya IP iweze kutoa nje. 204 00:09:40,920 --> 00:09:43,170 Na wakati kuungana kwa mtandao, inakupa moja. 205 00:09:43,170 --> 00:09:44,660 Basi hebu kupitia upya mchoro huu. 206 00:09:44,660 --> 00:09:49,660 Mahali fulani kati ya wewe na biashara, kuna DHCP server. 207 00:09:49,660 --> 00:09:50,160 SAWA. 208 00:09:50,160 --> 00:09:51,500 Hivyo hiyo ni nzuri. 209 00:09:51,500 --> 00:09:53,537 Sasa, hebu majadiliano juu ya DNS. 210 00:09:53,537 --> 00:09:55,370 Hivyo tumekuwa aliyesema ingawa anwani hizi IP. 211 00:09:55,370 --> 00:09:57,840 Tunajua kwamba kama sisi ni kwenda kipekee kutambua 212 00:09:57,840 --> 00:10:01,740 kifaa kwenye mtandao, ni ina kuwa na anwani ya kipekee. 213 00:10:01,740 --> 00:10:04,150 >> Na tunaweza kutembelea kwamba kushughulikia kama sisi alitaka. 214 00:10:04,150 --> 00:10:09,600 Lakini umefanya pengine kamwe typed katika kitu kama 192.168.1.0 215 00:10:09,600 --> 00:10:11,490 ndani ya browser yako, sawa? 216 00:10:11,490 --> 00:10:13,980 Huwezi aina katika idadi kwenye kivinjari chako. 217 00:10:13,980 --> 00:10:19,410 Kwa kawaida aina katika majina someka binadamu kama google.com au cs50.harvard.edu, 218 00:10:19,410 --> 00:10:20,640 sawa? 219 00:10:20,640 --> 00:10:22,880 >> Wale si anwani ya IP, ingawa. 220 00:10:22,880 --> 00:10:27,320 Hivyo ipo huduma hii aitwaye Jina Domain 221 00:10:27,320 --> 00:10:33,990 System, DNS, kwamba tafsiri ya IP anwani maneno kueleweka binadamu 222 00:10:33,990 --> 00:10:37,690 au misemo kwamba ni zaidi ya kukumbukwa kuliko kukumbuka seti ya namba nne 223 00:10:37,690 --> 00:10:40,430 au, hivi karibuni, seti ya nane idadi hexadesimoli. 224 00:10:40,430 --> 00:10:42,400 Hiyo itakuwa kweli changamoto, sawa? 225 00:10:42,400 --> 00:10:45,560 >> Kufikiria kabla Siku za simu za mkononi. 226 00:10:45,560 --> 00:10:47,730 Wewe alikuwa kukariri yako yako rafiki ya namba za simu. 227 00:10:47,730 --> 00:10:49,230 Ni inaweza kuwa na kujipatia mgumu baada ya muda mfupi. 228 00:10:49,230 --> 00:10:51,190 Na vile vile, kama unataka kutembelea rundo ya Nje, 229 00:10:51,190 --> 00:10:53,570 pengine hawataki kumbuka rundo la idadi. 230 00:10:53,570 --> 00:10:56,640 Wewe d badala kukumbuka rundo la maneno. 231 00:10:56,640 --> 00:11:01,930 >> Hivyo ramani hii, kutafsiri hii, bila seti ya namba kwa majina someka binadamu 232 00:11:01,930 --> 00:11:04,520 aina ya hufanya DNS kurasa njano ya mtandao. 233 00:11:04,520 --> 00:11:06,270 Na unaweza kufikiria juu ya ni kana kwamba ni tu 234 00:11:06,270 --> 00:11:14,305 orodha kubwa mbio kutoka 0.0.0.0 zote njia ya chini kwa 255.255.255.255, ambayo 235 00:11:14,305 --> 00:11:21,490 itakuwa possible-- ya juu hiyo ni mbalimbali kamili kutoka sekunde 0 na 255s ya yote 4 236 00:11:21,490 --> 00:11:25,525 bilioni-ish IPv4 anwani. 237 00:11:25,525 --> 00:11:27,400 Mimi linaloundwa na zile za juu na chini. 238 00:11:27,400 --> 00:11:30,500 Lakini moja katikati kuna ni kweli IP. 239 00:11:30,500 --> 00:11:38,440 Hivyo kama sisi alitembelea 74.125.202.138, inaonekana kwamba tafsiri na tovuti ya kwamba 240 00:11:38,440 --> 00:11:40,490 huko, io-- nini heck ni kwamba? 241 00:11:40,490 --> 00:11:46,290 Naam, si kila jina kwamba ramani ni kweli wazi ni nini, sawa? 242 00:11:46,290 --> 00:11:48,920 >> Hivyo wakati mwingine mtu ambaye anamiliki IP 243 00:11:48,920 --> 00:11:52,090 Huenda jina jeshi lake jambo kwamba wao ni kweli si. 244 00:11:52,090 --> 00:11:55,442 Kwa mfano, IP kwamba kama wewe walikwenda huko, ni kweli tu google.com. 245 00:11:55,442 --> 00:11:57,540 Lakini Google ina mengi watumishi wa tofauti. 246 00:11:57,540 --> 00:11:59,322 >> Na hawawezi kuwaita zote google.com. 247 00:11:59,322 --> 00:12:03,530 Hivyo kuwa yao wenyewe mfumo wa ndani kwa ajili ya kutafsiri 248 00:12:03,530 --> 00:12:09,125 google.com kwa kompyuta chochote kweli ni kushikamana na anwani ya IP huo. 249 00:12:09,125 --> 00:12:11,250 Na kisha kuna mwingine mfumo uliopo kati 250 00:12:11,250 --> 00:12:15,120 kutafsiri kwamba gobbledygook hapa google.com. 251 00:12:15,120 --> 00:12:16,830 Lakini sisi si kupata ndani ya kwamba. 252 00:12:16,830 --> 00:12:18,920 >> Na vile vile kwa IPv6s, sisi ni pia kwenda 253 00:12:18,920 --> 00:12:22,089 kuwa na kurasa njano kwamba utakuwa na mengi kubwa. 254 00:12:22,089 --> 00:12:23,880 Na vile vile, katika katikati there-- ilikuwa 255 00:12:23,880 --> 00:12:26,496 mgumu kupata IPv6 anwani hiyo ilikuwa halali. 256 00:12:26,496 --> 00:12:27,620 Lakini nimeona moja kwa Google. 257 00:12:27,620 --> 00:12:30,460 >> Lakini Google tovuti Ireland ni. 258 00:12:30,460 --> 00:12:34,170 Lakini kama wewe akaenda kuwa hotuba IPv6, kama browser yako alikuwa IPv6 wenye uwezo, 259 00:12:34,170 --> 00:12:36,940 ambayo ingeweza kuleta kwa Google Ireland Mzee. 260 00:12:36,940 --> 00:12:39,460 Hivyo kuna kwenda. 261 00:12:39,460 --> 00:12:41,830 >> Lakini hii si kweli kabisa, sawa? 262 00:12:41,830 --> 00:12:43,710 Mfumo huu inaonekana mbaya, sawa? 263 00:12:43,710 --> 00:12:47,220 Kama kuna orodha kubwa ya 4 mambo bilioni kwa kuwa na kuangalia juu, 264 00:12:47,220 --> 00:12:48,270 hiyo ni pretty kubwa. 265 00:12:48,270 --> 00:12:52,634 Hakuna kurasa njano ya dunia, sawa? 266 00:12:52,634 --> 00:12:54,800 Kama bado kupata njano kurasa mikononi you-- 267 00:12:54,800 --> 00:12:56,841 I got yangu siku nyingine, na mimi tu recycled yake. 268 00:12:56,841 --> 00:12:59,070 Lakini kama wewe kufanya kupata njano kurasa mikononi wewe, 269 00:12:59,070 --> 00:13:02,120 huwezi kupata kitabu kwamba ni kila namba ya simu ambayo ipo katika dunia, 270 00:13:02,120 --> 00:13:02,620 sawa? 271 00:13:02,620 --> 00:13:05,500 Kupata orodha ya namba za simu za mitaa, 272 00:13:05,500 --> 00:13:07,670 ndio wewe ni zaidi uwezekano wa kuwaita. 273 00:13:07,670 --> 00:13:09,400 >> Na hiyo ni kweli nini DNS ni. 274 00:13:09,400 --> 00:13:12,860 Kama unafikiri kuhusu hilo, DNS ni kweli ndani njano kurasa. 275 00:13:12,860 --> 00:13:17,350 Na kubwa servrar DNS kama google.coms, wao 276 00:13:17,350 --> 00:13:19,180 ni kweli tu zaidi kama maktaba kwamba 277 00:13:19,180 --> 00:13:25,470 kuwa na nakala ya yote ya njano ndani kurasa au wote wa kumbukumbu za mitaa DNS. 278 00:13:25,470 --> 00:13:29,520 Kwa hiyo, kuna kweli hakuna there moja ya DNS kamili ya biashara, 279 00:13:29,520 --> 00:13:32,410 kama hakuna mtu kurasa njano ya dunia. 280 00:13:32,410 --> 00:13:36,450 >> Kuna hizi ndogo zote za mitaa wadogo DNSs ambazo zipo huko nje. 281 00:13:36,450 --> 00:13:39,010 Na kuna huduma ambazo jumla ya mabao yao pamoja. 282 00:13:39,010 --> 00:13:42,174 Lakini wao wanategemea wale mifumo ndogo DNS 283 00:13:42,174 --> 00:13:45,340 kuhuisha taarifa zao, ili wana taarifa sahihi zaidi. 284 00:13:45,340 --> 00:13:48,500 >> Hivyo tena, mlinganisho huu ni kujumlisha kubwa 285 00:13:48,500 --> 00:13:51,910 Mifumo DNS ni kama maktaba kwamba kuwa na nakala 286 00:13:51,910 --> 00:13:56,410 ya kila kurasa njano ya dunia. 287 00:13:56,410 --> 00:13:58,350 Hawana wenyewe kuboresha vitabu hivyo. 288 00:13:58,350 --> 00:14:01,620 Wanategemea vitabu anaingia, ili waweze update habari 289 00:14:01,620 --> 00:14:04,560 kama wanahitaji hiyo. 290 00:14:04,560 --> 00:14:07,700 >> Hivyo mfumo DNS si kuzuia kubwa. 291 00:14:07,700 --> 00:14:11,026 Ni madaraka nchini wengi, wengi servrar. 292 00:14:11,026 --> 00:14:13,400 Hivyo sasa tunajua kwamba mahali fulani kati yetu na biashara 293 00:14:13,400 --> 00:14:18,350 kuna DNS server kama vile DHCP server. 294 00:14:18,350 --> 00:14:20,910 >> Sasa, pointi kupata, nini pointi za ufikivu zetu? 295 00:14:20,910 --> 00:14:23,840 Naam, pointi kupata wewe pengine pretty ukoo na kutoka kwa kweli 296 00:14:23,840 --> 00:14:24,964 kuunganisha na mtandao. 297 00:14:24,964 --> 00:14:28,820 Hiyo ni mtandao kwamba wewe kuchagua, nyumbani au kazi ya mtandao wako 298 00:14:28,820 --> 00:14:30,310 au kuwa na nini. 299 00:14:30,310 --> 00:14:32,597 >> Na mimi nina generalizing dhana ya kupata uhakika 300 00:14:32,597 --> 00:14:33,930 hapa kwa madhumuni ya video hii. 301 00:14:33,930 --> 00:14:35,721 Lakini kuna kweli mambo mengi ambayo 302 00:14:35,721 --> 00:14:38,766 inaweza zitakunjwa katika pointi kupata. 303 00:14:38,766 --> 00:14:41,890 Kuna dhana ya ruta, ambayo ni aina ya neno la jumla kwamba sisi kutumia. 304 00:14:41,890 --> 00:14:45,940 >> Lakini kuna pia swichi na mambo kweli kuitwa 305 00:14:45,940 --> 00:14:49,070 kupata pointi ambazo ni tofauti na Dhana hii ya jumla ya upatikanaji 306 00:14:49,070 --> 00:14:49,780 uhakika. 307 00:14:49,780 --> 00:14:54,510 Lakini kimsingi nini kinachotokea ni pamoja na IPv4, mimi 308 00:14:54,510 --> 00:14:57,030 Alisema tuna dhana hii ya anuani za binafsi, sawa? 309 00:14:57,030 --> 00:15:03,680 Na badala ya kila mashine kuwa anwani ya kipekee IP, ambayo 310 00:15:03,680 --> 00:15:07,720 sisi kukimbia nje ya, kwa sababu tuko juu ya vifaa bilioni 4 311 00:15:07,720 --> 00:15:09,860 kujaribu kuungana na biashara, nini cha kufanya 312 00:15:09,860 --> 00:15:12,810 ni badala kuwapa IP na router. 313 00:15:12,810 --> 00:15:15,960 Hiyo router au kupata uhakika tu nyumbani kwako, kwa mfano. 314 00:15:15,960 --> 00:15:19,280 >> Na kazi router kama kwa aina ya kazi kama askari wa trafiki, 315 00:15:19,280 --> 00:15:23,540 kuruhusu kila mtu ambaye ni kushikamana kwa kuwa router kutumia IP sawa 316 00:15:23,540 --> 00:15:25,115 kushughulikia kupata nje. 317 00:15:25,115 --> 00:15:25,990 Je, hiyo mantiki? 318 00:15:25,990 --> 00:15:29,414 Basi kila mtu katika nyumba yako ina IP binafsi. 319 00:15:29,414 --> 00:15:31,830 Hawawezi kuungana na biashara, au biashara badala 320 00:15:31,830 --> 00:15:34,870 hawezi kusema nao, kupitia kwamba anwani binafsi. 321 00:15:34,870 --> 00:15:37,656 Wanaweza tu kuzungumza nao kupitia anwani katika router. 322 00:15:37,656 --> 00:15:39,530 Na ni ya ruta kazi ya kuchukua maelezo 323 00:15:39,530 --> 00:15:42,900 kwamba wewe ni kutuma ruta na kuielekeza mahali sahihi 324 00:15:42,900 --> 00:15:46,890 na kwa taarifa kwamba kuja ndani ya router kwa ruta 325 00:15:46,890 --> 00:15:48,860 kutuma na wewe. 326 00:15:48,860 --> 00:15:52,470 >> Hivyo ruta ni kweli vifaa here-- hasa ruta 327 00:15:52,470 --> 00:15:59,010 katika nyumba yako, aina ya kawaida ya matumizi kesi kwa people-- zaidi 328 00:15:59,010 --> 00:16:00,870 ambayo ina IP umma. 329 00:16:00,870 --> 00:16:03,910 Hiyo ni kifaa kwamba kushikamana na mtandao. 330 00:16:03,910 --> 00:16:07,190 Na kuungana kwa router kuwa na mtiririko wa taarifa 331 00:16:07,190 --> 00:16:09,910 kwa njia hiyo kwa niaba yako. 332 00:16:09,910 --> 00:16:14,420 >> Kama nilivyosema, mtandao wa kisasa nyumbani, ruta na swichi na kupata uhakika 333 00:16:14,420 --> 00:16:16,420 ni kila aina ya kutunza juu katika kifaa moja. 334 00:16:16,420 --> 00:16:19,240 Wakati mwingine Modem ni kutunza katika huko pia. 335 00:16:19,240 --> 00:16:20,800 Hiyo kawaida tu kuitwa ruta. 336 00:16:20,800 --> 00:16:23,210 Lakini ni kweli wote wa mambo hayo kwa pamoja. 337 00:16:23,210 --> 00:16:27,870 >> Kubwa mitandao wadogo biashara au kinachojulikana Networks Wide Area, WANs, 338 00:16:27,870 --> 00:16:29,570 kweli kuweka vifaa hivi tofauti. 339 00:16:29,570 --> 00:16:30,470 Wana kubadili. 340 00:16:30,470 --> 00:16:31,550 Wana ruta. 341 00:16:31,550 --> 00:16:33,510 Wana pointi nyingi upatikanaji. 342 00:16:33,510 --> 00:16:36,250 >> Kwa mfano, katika chuo kikuu utaona mambo 343 00:16:36,250 --> 00:16:40,300 kwamba kuangalia kama kinachojulikana ruta lililotoka wote ni karibu chuo. 344 00:16:40,300 --> 00:16:44,120 Hayo ni mambo yote upatikanaji kwamba kati yake ndani ya ruta, swichi, nakadhalika, 345 00:16:44,120 --> 00:16:45,250 kupita habari pamoja. 346 00:16:45,250 --> 00:16:49,120 Kwa sababu mitandao hii ni hivyo kubwa kwamba moja moja kupata uhakika 347 00:16:49,120 --> 00:16:51,870 haiwezi kufunika eneo lake kubwa. 348 00:16:51,870 --> 00:16:54,990 >> Na hivyo mitandao hii kubwa, mitandao ya biashara, nakadhalika, 349 00:16:54,990 --> 00:16:57,710 kupasuliwa hizi katika tofauti vifaa, hivyo mtandao na wadogo 350 00:16:57,710 --> 00:16:59,780 na kukua kama inahitajika. 351 00:16:59,780 --> 00:17:04,180 Hivyo tena, mahali fulani kati yetu na biashara, tuna kupata uhakika. 352 00:17:04,180 --> 00:17:05,430 Na kwamba ni nini sisi kuungana na. 353 00:17:05,430 --> 00:17:08,992 Na kupitia huko, sisi wanaweza kupata internet. 354 00:17:08,992 --> 00:17:10,700 Kama nilivyosema mwanzo wa video hii, 355 00:17:10,700 --> 00:17:12,540 hii si kweli juu ya mitandao. 356 00:17:12,540 --> 00:17:13,990 Hivyo hii si hadithi nzima. 357 00:17:13,990 --> 00:17:15,109 Na nimekuwa aina ya glossed juu yake. 358 00:17:15,109 --> 00:17:17,150 Na labda nimekuwa kushoto wewe hata kidogo kuchanganyikiwa 359 00:17:17,150 --> 00:17:18,670 kama yale baadhi ya mambo haya ni. 360 00:17:18,670 --> 00:17:19,329 Lakini hiyo ni sawa. 361 00:17:19,329 --> 00:17:20,599 >> Hatuna haja ya hadithi nzima. 362 00:17:20,599 --> 00:17:25,250 Ni kutosha kwa ajili yetu ili kujua kusonga mbele tu kimsingi kidogo 363 00:17:25,250 --> 00:17:27,450 kuhusu jinsi biashara kazi. 364 00:17:27,450 --> 00:17:30,670 Kwa hiyo kile tunajua ni tuna hizi mitandao binafsi katika nyumba yetu. 365 00:17:30,670 --> 00:17:32,880 >> Na sisi kuungana na router. 366 00:17:32,880 --> 00:17:36,674 Na kwamba router ni kushikamana na mtandao kwa ujumla. 367 00:17:36,674 --> 00:17:38,090 Lakini ni nini biashara kwa ujumla? 368 00:17:38,090 --> 00:17:39,930 Mimi kuendelea kusema hayo, lakini ni nini? 369 00:17:39,930 --> 00:17:43,610 >> Naam, ni kweli tu haya yote mitandao ya mtu binafsi katika nyumba yangu, 370 00:17:43,610 --> 00:17:47,460 na katika nyumba yako, na katika kila mmoja nyumba, kwamba ni kushikamana pamoja. 371 00:17:47,460 --> 00:17:52,030 Ni iliyounganishwa mtandao, baina ya wavu. 372 00:17:52,030 --> 00:17:53,840 Hivyo badala ya kufikiri kuhusu biashara 373 00:17:53,840 --> 00:17:59,080 kama wingu hii kubwa, hii Ethereal jambo ambalo lipo huko nje, 374 00:17:59,080 --> 00:18:02,470 ni kweli tu uhusiano miongoni mwa wote wa mitandao hii. 375 00:18:02,470 --> 00:18:03,500 >> Hivyo hapa sisi kwenda. 376 00:18:03,500 --> 00:18:04,752 Tuna mtandao wetu wa ndani. 377 00:18:04,752 --> 00:18:07,210 Na sisi siyo mtu pekee pengine kwenye mtandao wetu wa ndani 378 00:18:07,210 --> 00:18:08,335 kujaribu kutumia mtandao. 379 00:18:08,335 --> 00:18:10,940 Kuna pengine kadhaa mmoja wetu kujaribu kupata katika. 380 00:18:10,940 --> 00:18:13,870 >> Na sisi siyo tu mtandao ambayo ipo katika dunia, sawa? 381 00:18:13,870 --> 00:18:18,300 Kuna mitandao mingine, pia kwamba ni kujaribu kuungana na mtandao. 382 00:18:18,300 --> 00:18:21,400 Lakini biashara ni la, tena, chombo tofauti. 383 00:18:21,400 --> 00:18:25,592 >> Ni tu mkusanyiko wa sheria ili kuruhusu mitandao hii, mitandao hii ndogo, 384 00:18:25,592 --> 00:18:27,300 bluu, zambarau, na mtandao nyekundu 385 00:18:27,300 --> 00:18:28,980 hapa, kuwasiliana na kila mmoja. 386 00:18:28,980 --> 00:18:31,230 Hivyo hakuna kitu ni wao ni wote kuunganisha na. 387 00:18:31,230 --> 00:18:35,010 Wao ni yote tu kushikamana kwa kila mmoja, haki? 388 00:18:35,010 --> 00:18:37,710 >> Na hivyo mahali fulani juu ya haya mitandao ipo huduma 389 00:18:37,710 --> 00:18:39,095 kwamba sisi kweli wanataka. 390 00:18:39,095 --> 00:18:41,220 Hivyo labda katika mtandao bluu Hapa ndipo Google anaishi. 391 00:18:41,220 --> 00:18:43,303 Na katika mtandao zambarau Hapa ndipo Picha anaishi. 392 00:18:43,303 --> 00:18:46,310 Na katika mtandao nyekundu, vizuri, labda hapo ndipo wale paka wote ni. 393 00:18:46,310 --> 00:18:49,440 >> Na hivyo kama tunataka kupata taarifa kuhusu paka, 394 00:18:49,440 --> 00:18:55,166 sisi tu traverse minyororo hii ya mitandao kupata taarifa tunataka. 395 00:18:55,166 --> 00:18:57,040 Na hapa, nimekuwa kuwakilishwa mtandao kama wote 396 00:18:57,040 --> 00:18:58,414 kuwa na uwezo wa kuzungumza na kila mmoja. 397 00:18:58,414 --> 00:19:00,300 Na tunaweza tu kuzungumza na mtandao. 398 00:19:00,300 --> 00:19:01,910 Lakini mtandao hawezi kuzungumza nyuma na sisi. 399 00:19:01,910 --> 00:19:03,326 >> Lakini hiyo si kweli aidha, haki? 400 00:19:03,326 --> 00:19:04,610 Hii yote ni njia mbili mitaani. 401 00:19:04,610 --> 00:19:07,860 Taarifa wanaweza kati yake kwa njia mitandao na kurudi. 402 00:19:07,860 --> 00:19:09,007 >> Jinsi gani kufanya hivyo? 403 00:19:09,007 --> 00:19:11,090 Naam, hakika ni biashara mfumo wa itifaki. 404 00:19:11,090 --> 00:19:11,970 Na tunakwenda kuanza kuzungumza juu ya kile 405 00:19:11,970 --> 00:19:14,130 itifaki hayo ni katika video ya baadaye. 406 00:19:14,130 --> 00:19:16,940 >> Lakini tena, biashara si jambo tofauti. 407 00:19:16,940 --> 00:19:20,760 Ni mkusanyiko wa sheria kwamba amefafanua jinsi mitandao kuwasiliana, 408 00:19:20,760 --> 00:19:23,410 mitandao hii ndogo, hizi mtandao wa ndani kwamba sisi ni kutumika, 409 00:19:23,410 --> 00:19:26,600 Watu katika nyumba zetu, watu katika shule zetu, watu katika kazi yetu, 410 00:19:26,600 --> 00:19:29,160 wote kugawana mtandao. 411 00:19:29,160 --> 00:19:31,900 Na jinsi mitandao hii kuunganisha na kuzungumza na kila mmoja, 412 00:19:31,900 --> 00:19:34,160 hiyo ni kweli nini biashara ya yote juu. 413 00:19:34,160 --> 00:19:36,090 Basi hebu, katika siku zijazo video, majadiliano juu ya baadhi 414 00:19:36,090 --> 00:19:38,940 ya itifaki kuwa wanaunda biashara kwa matumaini 415 00:19:38,940 --> 00:19:42,320 kukupa kidogo zaidi ya zilizofanyiwa ufahamu. 416 00:19:42,320 --> 00:19:43,320 Mimi nina Doug Lloyd. 417 00:19:43,320 --> 00:19:45,260 Hii ni CS50. 418 00:19:45,260 --> 00:19:47,351