ããã¯åå¿è åãã®å°ããªFAQã®ã»ã¬ã¯ã·ã§ã³ã§ãã
ïŒHãããã³ã«ã¯ã©ã®OSIã¬ãã«ã§æ©èœããŸããïŒ
ïŒã«ãŒã¿ãŒãšéå±€åã¹ã€ããã®éãã¯äœã§ããïŒ
ïŒãã©ã¯ãŒãã£ã³ã°ãã¬ãŒã³ãšã³ã³ãããŒã«ãã¬ãŒã³ã®éãã¯äœã§ããïŒ
ïŒMTUãšMSSã®éãã¯äœã§ããïŒ
ïŒVLANãšBVIã®éãã¯äœã§ããïŒ
ïŒãã³ãã«ã€ã³ã¿ãŒãã§ãŒã¹ã¯ã©ã®ããã«æ©èœããŸããïŒ
ïŒNATã®4çš®é¡ã®ã¢ãã¬ã¹ã¯ã©ãããæå³ã§ããïŒ
ïŒNATããŒã«ã§ãããã¯ãŒã¯ã¢ãã¬ã¹ãšãããŒããã£ã¹ãã¢ãã¬ã¹ã䜿çšã§ããŸããïŒ
ïŒãªãIPã¢ãã¬ã¹ãå¿ èŠãªã®ã§ããïŒ ãã¹ãŠã«å¯ŸããŠååãªMACã¢ãã¬ãã·ã³ã°ã§ã¯ãããŸãããïŒ
ïŒQoSã¯åž¯åå¹ ãæ¡åŒµããŸããïŒ
ïŒHãããã³ã«ã¯ã©ã®OSIã¬ãã«ã§æ©èœããŸããïŒ
ãããã¯ãŒã¯ãç 究ãã人ãæåã«çŽé¢ããã®ã¯ãOSIïŒOpen Systems InterconnectionïŒã¢ãã«ã§ãã ããã¯ãIOS / IEC 7498-1ã§å ¬åŒã«å®çŸ©ããã7ã¬ãã«ã®åç §ã¢ãã«ã§ãã ããªãã¯ãããŸã§ã«åºçãããæè²æç®ã§åœŒå¥³ã«äŒããŸãã ãããã³ã«ã®çžäºäœçšãè°è«ãããšããOSIãåç §ããããšã¯éåžžã«äžè¬çã§ãã ãããã£ãŠãããšãã°ãTCPã¯ç¬¬4ã¬ãã«ã®ãããã³ã«ã§ãããIPã®éŠã«äœçœ®ããŠããŸã-第3ã¬ãã«ã®ãããã³ã«ã§ãã
ããããããã¯æ¬åœã«äœãæå³ããã®ã§ããããïŒ ãããã³ã«ãå±ããã¬ãã«ã¯èª°ã決å®ããŸããïŒ OSIã¢ãã«ã¯ãOSIãããã³ã«ãã¡ããªã®äžéšãšããŠ70幎代ã«èæ¡ãããŸãããOSIãããã³ã«ãã¡ããªã¯ãçå£ã«TCP / IPã¹ã¿ãã¯ã®ã©ã€ãã«ãšããŠäœçœ®ä»ããããŸããïŒãã¿ãã¬ïŒTCP / IPã¯ãŸã åã¡ãŸããïŒã å°æ°ã®çåè ãé€å€ããå ŽåïŒç¢ºãã«ãåçã«ãŒãã£ã³ã°ãããã³ã«IS-ISã«ã€ããŠèããããšãããïŒãOSIãããã³ã«ã¯å®éã«ã¯äœ¿çšãããŸããã ãã ããOSIåç §ã¢ãã«ã¯ãããããã©ã®ããã«çžäºäœçšããããèšè¿°ããŠããããã¹ãŠã®çç©ããã掻çºã§ãã ãã ãããããã¡ããªã®ãããã³ã«ãå¥ã®ãã¡ããªã«å®çŸ©ãããã¬ãã«ã«ãã€ã³ãããŸãã
ã»ãšãã©ã®å Žåããã¹ãŠãæ£åžžã«æ©èœããŸããTCPãšUDPãIPã«ä¹ãããããé çªã«ã€ãŒãµããããPPPãªã©ã«ç§»è¡ããŸãã ãããã40幎åã®ã¢ãã«ã§ã¯ãçŸä»£ã®ãããã³ã«ã®ããŒãºãåžžã«æºããããšã¯ã§ããŸããã MPLSãäŸã«åããŸãã å€ãã®å Žåãã¬ãã«2.5ãšåŒã°ããŸããããã¯ããã¬ãŒã ã®åœ¢æããšã³ãããŒãšã³ãã®ã¢ãã¬ã¹æå®ãå®è¡ããã«ããã£ãã«ã®äžéšã§ãããã¯ãŒã¯ã®äžã§æ©èœããããã§ãïŒIPã¢ãã¬ã¹ãšã¯ç°ãªããMPLSã©ãã«ã¯åããŒãã§ãã±ããããã€ã³ãã«ç§»åãããšãã«å€æŽãããŸãå®å ïŒã ãã¡ãããä»ã®2ã€ã®éã«æ°ããã¬ãã«ãè¿œå ãããšãæšæºã¢ãã«ãç Žå£ãããŸãã
å³å¯ã«èšãã°ãTCP / IPã¹ã¿ãã¯ã®åäžã®ãããã³ã«ãOSIã¬ã€ã€ãŒã«æ£åŒã«å²ãåœãŠãããããã§ã¯ãããŸããããããã¯ç°ãªããã¡ããªãŒã§ããããã§ãã ãªã³ãŽãšãªã¬ã³ãžã åç §ã¢ãã«ã¯åç §ã§ãïŒ ç¿»èš³è ã®ã¡ã¢ïŒçµå±ã®ãšããããã·ã¢èªã®ååã¯åç §ã¢ãã«ã«å°ã察å¿ããŠããŸãããåç §ã¯ãã®çæ³æ§ãšããã«æºæ ããããšããæã蟌ã¿ãæã£ãŠããŸã ïŒã OSIã¯ãäžéšã®ãããã³ã«ãä»ã®ãããã³ã«ã«äŸåããŠããããšãããã³ã ãã誰ãè¿œããããŠãããã瀺ãã®ã«åœ¹ç«ã¡ãŸããããããã®æ©èœãæ瀺ããããšã¯ã§ããŸããã
ãããã誰ããçªç¶è³ªåããå ŽåãMPLSã¯ç¬¬3ã¬ãã«ã®ãããã³ã«ã§ãããšçããŠãã ããã
ïŒã«ãŒã¿ãŒãšéå±€åã¹ã€ããã®éãã¯äœã§ããïŒ
æã¯ãã«ãŒã¿ãŒã¯IPã¢ãã¬ã¹ã«åºã¥ããŠãã±ãããéä¿¡ããã€ãŒãµããããE1ãã·ãªã¢ã«ãOC-3ãªã©ã®å¹ åºãã€ã³ã¿ãŒãã§ã€ã¹ãæäŸããŠããŸããã åæã«ãã¹ã€ããã¯MACã¢ãã¬ã¹ã«åºã¥ããŠãã±ããïŒãã¬ãŒã ããããéå±ãªãªãŒã°ã®å ŽåïŒãéä¿¡ããã€ãŒãµãããããŒãã®ã¿ãæã£ãŠããŸããã
ãããã2000幎代åé ã«ããã®éãã«å¯Ÿããæ確ãªç解ãçµãããŸããã2ã€ã®éèŠãªåŸåãçŸããŸããã ãŸããIPã¢ãã¬ã¹ã«åºã¥ããŠãã±ããã転éããæš©å©ãåãåãã ãã§ãªããå®éã®ã«ãŒã¿ãŒã®ãããªåçã«ãŒãã£ã³ã°ãããã³ã«ã«ãåå ãããã«ãã¬ãã«ã¹ã€ãããç»å ŽããŸããã 第äºã«ãéä¿¡äºæ¥è ã¯ãåç·äº€ææè¡ããè¿ä»£çãªã€ãŒãµããããžã®äžå¯éçãªç§»è¡ããã»ã¹ãéå§ããŸãããããã«ãããé«éã§äœã³ã¹ããå®çŸããŸãã çŸåšãã«ãŒã¿ãŒãã€ãŒãµãããã€ã³ã¿ãŒãã§ã€ã¹ã®ã¿ãåããŠããå Žåãã¹ã€ããã®ããã«å®å šã«æ£åžžã§ãã
ã«ãŒã¿ãŒãšéå±€åã¹ã€ããã®å¢çã¯ã©ãã§ããïŒ ãã®å¢çç·ã¯ãŸã ååšããŸããïŒ
ãããã®å®éã®éãã¯ã次ã®ããã€ãã®ç¹ã«ãããŸãã
- ããŒãå¯åºŠã éåžžããšã³ã¿ãŒãã©ã€ãºã¹ã€ããã¯24ãŸãã¯48ããŒããæèŒããŠããŸãã å Žåã«ãã£ãŠã¯ãããã«æ¡åŒµããããã«ç©ã¿éããããšãã§ããŸãã äž»ãªç®æšïŒããã³ãããã«ãèš±ãéãå€ãã®ã€ã³ã¿ãŒãã§ãŒã¹ãããã·ã¥ããããšã å察ã«ãã«ãŒã¿ãŒã«ã¯éåžžãã¯ããã«å°ãªãã€ã³ã¿ãŒãã§ãŒã¹ããããå Žåã«ãã£ãŠã¯ç°ãªããã©ã°ã€ã³ã«ãŒãäžã«ééããããŸãã ïŒãã©ã³ã¹ã¬ãŒã¿ã«æ³šæããŠãã ããïŒãã£ãªã¢ã¯ã©ã¹ã®æ©åšã«ã€ããŠè©±ããŠããå Žåãã«ãŒã¿ã®ã©ã€ã³ã«ãŒãäžã®ããŒãã®å¯åºŠã¯ã¹ã€ãããšéåžžã«å¹æµããŸãïŒã
- ã¹ããŒãã ã¹ã€ããã¯ãã©ãã£ãã¯ãè±ç©ããããã«èšèšãããŠããŸãã çŸåšãæ§ãããªãªãã£ã¹ã¹ã€ããã§ããåç·é床ã§åž¯åå¹ ãæäŸããããšããããããŸãã ããã¯ããã©ãã£ãã¯ãCPUã®é¢äžãªãã«ããŒããŠã§ã¢ãããã»ããã§åŠçããããšããäºå®ã«ããå®çŸãããŸãã ïŒç¿»èš³è ã«ãã泚æïŒããã§ãã«ãŒã¿ãŒã¯ãã©ãã£ãã¯äŒéã«äž»ã«FPGAãšASICã䜿çšãã垯åå¹ ã¯ã¹ã€ããã«å£ããªãããšã«æ³šæããŠãã ããïŒã
- ã€ã³ããªãžã§ã³ã¹ã ã«ãŒã¿ãŒã®éžæãäœåãªããããäž»ãªéãã¯ãç¥çã¹ã¿ããã£ã³ã°ã§ãã ã«ãŒã¿ãŒã¯ãNATãDPIãã¹ããŒããã«ãã¡ã€ã¢ãŠã©ãŒã«ãæå·åãªã©ã®æ©èœãæäŸããŸããããããã¹ãŠã¯ãååãšããŠãã¹ã€ããã§ã¯ãµããŒããããŠããŸããã
ããã¯ãšããããçŸä»£äžçã¯ç¹å®ã®ããŒãºã®ããã«è£œé ãããæ©åšã«åºã¥ããŠããŸãã ãã ããNFVãšSDNã®ä»®æ³ã€ã³ã¿ãŒãã§ã€ã¹ã§ææ¥ãèŠããšãåãããã¯ã¹ããããã¯ãŒã¯äžã®äœçœ®ã«å¿ããŠå®å šã«ç°ãªã圹å²ãæããããšãã§ãããšããçµè«ã«éããŸãã
ïŒãã©ã¯ãŒãã£ã³ã°ãã¬ãŒã³ãšã³ã³ãããŒã«ãã¬ãŒã³ã®éãã¯äœã§ããïŒ
åå¿è ã«ãšã£ãŠãããã¯ééããªãæ··ä¹±ã®åå ã§ãã
ãã©ã¯ãŒãã£ã³ã°ãã¬ãŒã³ã¯ãã°ãã°ããŒã¿ãã¬ãŒã³ãšåŒã°ãããã·ã¢èªã§æãæåãããªãã·ã§ã³ã¯ã¹ã€ããã³ã°ãã¬ãŒã³ã§ãã ãã®ã¿ã¹ã¯ã¯ãã€ã³ãAãããã€ã³ãBãŸã§ãã±ãããå±ããããšã§ãã ã¹ã€ããã³ã°ã®é£è¡æ©ã¯éå€ããŸãã
ã³ã³ãããŒã«ãã¬ãŒã³ - ã³ã³ãããŒã«ãã¬ãŒã³ -ã¹ã€ããã³ã°ãã¬ãŒã³ã®åäœæ¹æ³ãèŠå®ããæ©èœãæäŸããŸãã ã³ã³ãããŒã«ãã¬ãŒã³ã³ã³ãããŒã« ã
ããšãã°ãOSPFãåããã«ãŒã¿ãŒããããŸãã ã«ãŒãã£ã³ã°æ å ±ãé£æ¥ããOSPFã«ãŒã¿ãŒãšäº€æãããããã¯ãŒã¯å šäœã®ã°ã©ããäœæããŠãã«ãŒããèšç®ããŸãã ã«ãŒãã£ã³ã°ããŒãã«ïŒRIBïŒãæ§ç¯ããããšãã«ãŒã¿ãŒã¯ã¹ã€ããã³ã°ããŒãã«ïŒFIBïŒã®æ¢ç¥ã®åå®å ãžã®æé©ãªã«ãŒããã€ã³ã¹ããŒã«ããŸãã ãããã¯ãã³ã³ãããŒã«ãã¬ãŒã³ã®æ©èœã§ãã
åãã«ãŒã¿ãŒãIPãã±ãããåä¿¡ãããšãã¹ã€ããã³ã°ããŒãã«ã§å®å ã¢ãã¬ã¹ãæ¢ããŠããã±ããã®éä¿¡å ãšãªãã€ã³ã¿ãŒãã§ã€ã¹ã決å®ããŸãã 次ã«ããã±ããã¯åºåã€ã³ã¿ãŒãã§ã€ã¹ãããã¡ã«è»¢éããã次ã«ã±ãŒãã«ã«è»¢éãããŸãã ãããã¯ããã©ã¯ãŒãã£ã³ã°ãã¬ãŒã³ã®æ©èœã§ãã
éããæããŸããïŒ ã¹ã€ããã³ã°ãã¬ãŒã³ã¯ãã±ããã®éåä¿¡ãæ åœããã³ã³ãããŒã«ãã¬ãŒã³ã¯ãã±ãããéä¿¡ãã決å®ãæ£ç¢ºã«è¡ãããæ¹æ³ãæ åœããŸãã
éåžžãã¹ã€ããã³ã°ãã¬ãŒã³ã¯ããŒããŠã§ã¢ã§å®è£ ãããŸããã€ãŸããCPUãžã®ã¢ã¯ã»ã¹ãå¿ èŠãšããã«ãç¹å¥ãªãããã»ããã«ãã£ãŠå®è¡ãããŸãïŒããšãã°ããããã¯ãŒã¯ããã»ããµã¯TCAMã䜿çšããŠFIBããåºåã€ã³ã¿ãŒãã§ã€ã¹ããã°ããæœåºããŸãïŒã
ã³ã³ãããŒã«ãã¬ãŒã³ã¯ãCPUãšéåžžã®ã¡ã¢ãªã§ãåäœããŸããããã¯ãããŒãœãã«ã³ã³ãã¥ãŒã¿ãŒã®æäœãšéåžžã«ãã䌌ãŠããŸãã äºå®ãå¶åŸ¡ã¬ãã«ã¯éåžžã«è€éãªæ©èœãå®è¡ããŸãããäžæ¹ã§ã¯ãªã¢ã«ã¿ã€ã ã§å¿ èŠãšããããä»æ¹ã§ã¯ããããããŒããŠã§ã¢ã§å®è£ ããã®ã¯åé¡ã§ãã ããšãã°ãã«ãŒã¿ãã¹ã€ããã³ã°ããŒãã«ã«ã«ãŒããã€ã³ã¹ããŒã«ããå Žåãæ°ããªç§ã®é 延ã¯éèŠã§ã¯ãããŸããããã¹ã€ããã³ã°ã¬ãã«ã§ã¯ããã©ãŒãã³ã¹ãå€§å¹ ã«äœäžããå¯èœæ§ããããŸãã
ïŒMTUãšMSSã®éãã¯äœã§ããïŒ
æ倧äŒéåäœïŒMTUïŒã¯ã1ã€ã®ãã±ãããäŒéã§ããããŒã¿ã®æ倧éã瀺ããŸãã éåžžãEthernerã«é¢ããŠMTUã«ã€ããŠè©±ããŸãïŒãã¡ãããä»ã®ãããã³ã«ã«ãç¬èªã®MTUããããŸãïŒã ã»ãšãã©ã®ãã©ãããã©ãŒã ã®ããã©ã«ãMTUã¯1500ãã€ãã§ãã ããã¯ãããŒãã1,500ãã€ãã®ãã€ããŒããéã¶ãã¬ãŒã ãéä¿¡ã§ããããšãæå³ããŸãã ããã«ã¯ã14ãã€ãã®ã€ãŒãµãããããããŒïŒ802.1qã®å Žåã¯18ïŒãš4ãã€ãã®FSCãã£ãŒã«ãã¯å«ãŸããŸããã æçµçãªãã¬ãŒã ãµã€ãºã¯1518ãã€ãïŒ802.1qã®å Žåã¯1522ïŒã§ãã å€ãã®ããŒãããžã£ã³ããã¬ãŒã ããµããŒãããããã«ãªããŸãããããã«ãããæšæºMTUã¯9000ãã€ã以äžã«å¢å ããŸãã
æ倧ã»ã°ã¡ã³ããµã€ãºïŒMSSïŒã¯ããã±ããã®æ倧TCPãã€ããŒãã瀺ãTCPã®ç¹æ§ã§ãããå®éãããã¯TCPã®MTUã§ãã TCP MSSã¯ãã€ã³ã¿ãŒãã§ã€ã¹ã®ã€ãŒãµãããMTUïŒã€ãŒãµãããã§ã¯ãªãå¯èœæ§ããããŸãïŒã«åºã¥ããŠèšç®ãããŸãã TCPã¯ã€ãŒãµããããã¬ãŒã ã«å§å ¥ããå¿ èŠããããããMSSã¯MTUãããå°ãããªããã°ãªããŸããã çæ³çã«ã¯ãMSSã¯å¯èœãªéãé«ãããå¿ èŠããããŸããããããŒã®MTUãµã€ãºTCPããããŒã®IPãµã€ãºã
MTUã1500ãã€ãã§ãããšä»®å®ããŠã20ãã€ãã®IPv4ã¢ãã¬ã¹ãšããã«20ãã€ãã®TCPãæžç®ããMSS 1460ãã€ããååŸããŸãã æ¡åŒµããããŒãåããIPv6ã¯ãMSSçšã«1440ãã€ãã®ã¿ãæ®ããŸãã
TCP MSSã¯ãæ¥ç¶ã®ã»ããã¢ããäžã«äžåºŠæ±ºå®ãããŸãã åããŒãã¯ãæåã®ãã±ããïŒSYNãã©ã°ã®ãããã®ïŒã®TCPãªãã·ã§ã³ã«MSSãå«ããäž¡æ¹ã®ããŒãã2ã€ã®æå°å€ãMSSã»ãã·ã§ã³ãšããŠéžæããŸãã 確ç«ãããMSSã¯ãã»ãã·ã§ã³ã®åç¶æéäžã«å€æŽãããŸããã
ïŒVLANãšBVIã®éãã¯äœã§ããïŒ
VLANã€ã³ã¿ãŒãã§ãŒã¹ ïŒSVIïŒã¹ã€ããä»®æ³ã€ã³ã¿ãŒãã§ãŒã¹ïŒãŸãã¯RVIïŒã«ãŒãããVLANã€ã³ã¿ãŒãã§ãŒã¹ïŒãšãåŒã°ããŸãïŒã¯ããã«ãã¬ãã«ã¹ã€ããäžã®ä»®æ³ã€ã³ã¿ãŒãã§ãŒã¹ã§ãã ã«ãŒãã£ã³ã°ãæäŸããå€ãã®å ŽåãããŒã«ã«ãããã¯ãŒã¯ã»ã°ã¡ã³ãã®ããã©ã«ãã²ãŒããŠã§ã€ãšããŠæ©èœããŸãã VLANã€ã³ã¿ãŒãã§ã€ã¹ã¯éåžžãã«ãŒã¿ãŒã®ç©çã€ã³ã¿ãŒãã§ã€ã¹ãšããŠåäœããæ§æãããŸããIPãå²ãåœãŠãããVRRPã«åå ããããACLãèšå®ãããã§ããŸãã ããã¯ã¹ã€ããå éšã®ç©çã€ã³ã¿ãŒãã§ã€ã¹ã§ãããšæ³åã§ããŸããããã®VLANãçµç«¯ããã¹ã€ããå€éšã®ã«ãŒãã£ã³ã°ã€ã³ã¿ãŒãã§ã€ã¹ã§ãããšæ³åã§ããŸãã
ããªããžã°ã«ãŒãã®ä»®æ³ã€ã³ã¿ãŒãã§ã€ã¹ïŒBVIïŒã¯åæ§ã®ç®çãæãããŸãããããŒãã¯éåžžL3ã§æ©èœãããããVLANã®æŠå¿µãæããªãã«ãŒã¿ãŒã«ååšããŸãïŒ ç¿»èš³è ã®æ³šæïŒVLANã®æŠå¿µã¯ã«ãŒã¿ãŒã«ãååšããå¯èœæ§ããããŸã ïŒã ããªããžã°ã«ãŒãã¯ã2ã€ä»¥äžã®ããŒãã匷å¶çã«L2ã§åäœããããããã®éã§ãããŒããã£ã¹ããã¡ã€ã³ãåé¢ããŸãã BVIã¯ãããªããžã°ã«ãŒãã®ã€ã³ã¿ãŒãã§ã€ã¹ãæ¥ç¶ããããã«æ¥ç¶ãããŠãããã¹ãŠã®ã»ã°ã¡ã³ãã®ä»®æ³L3ã€ã³ã¿ãŒãã§ã€ã¹ãšããŠæ©èœããŸãã ã«ãŒã¿ãŒãL2ãšL3ã§åæã«å®è¡ãããå Žåãçµ±åã«ãŒãã£ã³ã°ãšããªããžã³ã°ïŒIRBïŒãšåŒã°ããŸãã
VLANã€ã³ã¿ãŒãã§ã€ã¹ã¯ãã«ãã¬ãã«ã¹ã€ããã«äžå¯æ¬ ãªãã®ã§ãããIRBã¯ãããšãã°WiFiã¢ã¯ã»ã¹ãã€ã³ãã§äœ¿çšã§ããããããªãã®ã§ãã
ïŒãã³ãã«ã€ã³ã¿ãŒãã§ãŒã¹ã¯ã©ã®ããã«æ©èœããŸããïŒ
å€ãã®äººããã³ãã«ã€ã³ã¿ãŒãã§ãŒã¹ã®æŠå¿µãç解ããã®ã«èŠåŽããŠããŸãïŒ ç¿»èš³è ã®ã¡ã¢ïŒæ¬åœã«ïŒ ïŒã ãã³ããªã³ã°ãšã¯ã1ã€ã®ãã±ãããå¥ã®ãã±ããã«ã«ãã»ã«åããŠã2ã€ã®ãã€ã³ãéã§è»¢éããããšã§ãã ãã³ãã«ã€ã³ã¿ãŒãã§ã€ã¹ã¯ãåºç€ãšãªããããã¯ãŒã¯ã®ããããžãä¿è·ããã³æœè±¡åããã«ãŒãããVPNã®ã«ãã»ã«åãå®çŸããããã«äœ¿çšãããŸãã IPSecãGREãMPLSãªã©ãå«ãå€ãã®ã«ãã»ã«åæ¹æ³ããããŸãã
ãã³ãã«ã€ã³ã¿ãŒãã§ã€ã¹ã¯æ¬è³ªçã«ä»®æ³ã§ããã«ãããããããã«ãŒãã£ã³ã°ã«é¢ããŠã¯ä»ã®ã€ã³ã¿ãŒãã§ã€ã¹ãšåæ§ã«åäœããŸãããå¯äžã®éãã¯ããã³ãã«ã€ã³ã¿ãŒãã§ã€ã¹ãä»ããŠãã±ãããéä¿¡ããããšãæ°ãããã±ããã«ããã±ãŒãžåãããããšã§ããã«ãŒãã£ã³ã°ã æ°ããåŠåš ããã±ãŒãžãæ°Žææ¥ã«åºçºããæçµçã«ç®çå°ã«å°çããŸãã ãã³ãã«ã®ããäžæ¹ã®ç«¯ã§ãå€åŽã®ããããŒãåé€ãããå ã®ãã±ãããåºãŠããŸãããã®äžã§ãã«ãŒãã£ã³ã°ã®æ±ºå®ãå床è¡ãããŸãã
ïŒNATã®4çš®é¡ã®ã¢ãã¬ã¹ã¯ã©ãããæå³ã§ããïŒ
NATã®ã³ã³ããã¹ãã«ã¯ãIPã¢ãã¬ã¹ã®4ã€ã®ã¯ã©ã¹ããããŸãã
- å éšã°ããŒãã«
- å°å å
- å°å å€
- å€ã®ã°ããŒãã«
æ®å¿µãªããããããã®çšèªãããã¥ã¡ã³ãã§èª¬æãããŠããããšã¯ãã£ãã«ãããŸããã
ãããã¯ãããããlocationãšlocationã® 2ã€ã®å±æ§ãèšè¿°ããŸã ã
å Žæã¯åé¡ã®ããŒãã瀺ããŸãã ãããã¯ãŒã¯ã®å éšïŒNATã®åïŒ-å éšã å€éšãããã¯ãŒã¯ïŒNATåŸïŒ-å€éšã
èŠç¹ã¯ããã®ããŒããèŠãŠããå Žæã瀺ããŸãã ãããã¯ãŒã¯å -ããŒã«ã«; å€éšãããã¯ãŒã¯ãã-ã°ããŒãã«ã
ããšãã°ããã©ã€ããŒãã¢ãã¬ã¹192.168.0.10ã®ã³ã³ãã¥ãŒã¿ãŒããTelnetçµç±ã§ã€ã³ã¿ãŒãããã¢ãã¬ã¹94.142.241.111ã«ãã°ã€ã³ããå ŽåãèããŠã¿ãŸãããã NATããŒã«ãããIPã¢ãã¬ã¹192.0.2.10ãå²ãåœãŠãããŸãã
ãããå€æããŒãã«ã®å€èŠ³ã§ãã
R2# show ip nat translations Pro Inside global Inside local Outside local Outside global tcp 192.0.2.10:32978 192.168.0.10:32978 94.142.241.111:23 94.142.241.111:23
ãããç解ããŸããããïŒ
Inside Global-å éšããŒããå€éšããã©ã®ããã«èŠãããã ã€ã³ã¿ãŒãããäžã®ãµãŒããŒã¯ãNATããŒã«ã®ã¢ãã¬ã¹ãå®éã«èªèããŸãã
Inside Local-å éšããå éšã¢ãã¬ã¹ãã©ã®ããã«èŠããã-ã³ã³ãã¥ãŒã¿ãŒã®ãã©ã€ããŒãã¢ãã¬ã¹
å€éšããŒã«ã«-å€éšã¢ãã¬ã¹ãå éšã§ã©ã®ããã«èŠããã-ãããªãã¯ã¢ãã¬ã¹ãšããŒã23ã衚瀺ãããŸãã
å€éšã°ããŒãã«-å€éšããã®å€éšã¢ãã¬ã¹ã¯æ¬¡ã®ããã«ãªããŸãããNATã¯ãã®ãããªå€æãèªèããªããããã¢ãã¬ã¹ã¯å€éšããŒã«ã«ãšäžèŽããŸãã
ïŒNATããŒã«ã§ãããã¯ãŒã¯ã¢ãã¬ã¹ãšãããŒããã£ã¹ãã¢ãã¬ã¹ã䜿çšã§ããŸããïŒ
ã¯ã
ãŸããNATããŒã«ã®ã³ã³ããã¹ãã§ã¯ããã¹ã¯ãããã¯ãŒã¯ã¢ãã¬ã¹ãšãããŒããã£ã¹ãã¢ãã¬ã¹ã®æŠå¿µã¯ãããŸããã
ããã«çŽ 翻蚳è ã
次ã«ããããã¯ãŒã¯ã¢ãã¬ã¹ãšãããŒããã£ã¹ãã¢ãã¬ã¹ã¯ãµãããããã¹ã¯ã«ãã£ãŠæ±ºå®ãããŸãããµãããããã¹ã¯ããªããšãæå³ã倱ãããŸãã ãããã£ãŠãã¢ãã¬ã¹192.168.0.255ããããŒããã£ã¹ãã¢ãã¬ã¹ãšèŠãªãã192.168.1.0ããããã¯ãŒã¯ã¢ãã¬ã¹ãšèŠãªããã©ããã¯ããã¹ã¯ã«å®å šã«äŸåããŸãã/23ã®å Žåãçãã¯noã/ 24以äžã®å Žåãçãã¯yesã§ãã
ãã®ãããããŒã«ã§ã¢ãã¬ã¹192.168.0.255ãæå®ã§ããã ãã§ãªãã/ 23ãã¹ã¯ã䜿çšããŠã€ã³ã¿ãŒãã§ã€ã¹äžã§æ§æããããšãã§ããŸãã
ïŒãªãIPã¢ãã¬ã¹ãå¿ èŠãªã®ã§ããïŒ ãã¹ãŠã«å¯ŸããŠååãªMACã¢ãã¬ãã·ã³ã°ã§ã¯ãããŸãããïŒ
åå¿è ãMACã¢ãã¬ã¹ãåŠç¿ãå§ãããšããããã¯ã°ããŒãã«ã«äžæã§ãªããã°ãªããªãããšãããããŸãã ãããŠãè«ççãªçåãçããŸããIPããŸã£ãã䜿çšããã«ãã€ã³ã¿ãŒãããå šäœã§ãšã³ãããŒãšã³ãã®ã¢ãã¬ã¹æå®ã«MACã¢ãã¬ã¹ã䜿çšããªãã®ã¯ãªãã§ããã ãã ããIPãåŒãä»ããã«ã¯ããã€ãã®çç±ããããŸãã
ãŸãããã¹ãŠã®ãããã¯ãŒã¯ã«MACã¢ãã¬ã¹ãèšå®ãããŠããããã§ã¯ãããŸããã äžè¬ã«ããã®ã¿ã€ãã¯ãã¡ããª802ã«ã®ã¿åºæã§ããã»ãšãã©ãã¹ãŠãã€ãŒãµããããŸãã¯ãã®ããªãšãŒã·ã§ã³ïŒIEEE 802.11 WiFiãªã©ïŒã§ããäžçã§ã¯ããã®ã¿ã€ããå¿ããã¡ã§ãã ããããæ°å幎åã®ã€ãŒãµãããã®è¥è ã§ã¯ããããã³ã«ã®åéã§ã®ç¡æ³ç¶æ ã暪è¡ããŠããŸãããããŒã¯ã³ãªã³ã°ãã€ãŒãµãããããã¬ãŒã ãªã¬ãŒãATMã¯ã«ãŒã¿ãŒã®å Žæã®ããã«æŠããŸããã ãŸããããŒã¯ã³ãªã³ã°ã®ããŒããšMACã¢ãã¬ã¹ãä»ããATMã®ããŒããšã®çžäºäœçšã確å®ã«ããã«ã¯ããããã¯ãŒã¯å±€ãããã³ã«ãå¿ èŠã§ããã
次ã«ãIPã¢ãã¬ã¹ã¯ã¢ãã€ã«ã§ã-管çè ãå²ãåœãŠãããšããèªåçã«çºè¡ããããšãã§ããŸãããMACã¢ãã¬ã¹ã¯ãããã¯ãŒã¯ã¢ããã¿ãŒã«æ°žä¹ ã«çž«ãä»ããããŸãã æè¡çã«ã¯ããã¡ããMACã¢ãã¬ã¹ãå€æŽã§ããŸãããããã¯æ¬æ¥æå³ããããã®ã§ã¯ãªããçŸåšã䟿å©ãªç®¡çã®ããã®ããŒã«ã¯ãããŸããã
ãããã3çªç®ã®äž»ãªçç±ã¯ãIPãã¹ã±ãŒã©ãã«ã§å·šå€§ãªãããã¯ãŒã¯ã«æ¥ç¶ã§ããããšãšãã€ãŒãµããããå°ããªã»ã°ã¡ã³ãã®éåœã ãšããããšã§ãã IPã¢ãã¬ã¹ã®ã¹ããŒã¹ã¯éå±€çã§ãããMACã¢ãã¬ã¹ã¯ãã©ããã§ãã 1ã€ã®ããŒã«ã«ãããã¯ãŒã¯ã®254ããŒãã¯ã1ã€ã®24ãµããããã«éçŽã§ããŸãã 8/24ãµããããã¯ã1ã€/ 21ã«éçŽã§ããŸãã ããã¯ãéåžžãã¢ãã¬ã¹ãããã¯ãã€ã³ã¿ãŒãããã®è¿ãã«ããããã§ãã ãã®å Žåãã«ãŒã¿ãŒãåŠçããå¿ èŠãããã®ã¯ããµããããã«å°éããæ¹æ³ã ãã§ãã
MACã¢ãã¬ã¹ã¯ãå·¥å Žã§ç䌌ã©ã³ãã ã«å²ãåœãŠãããŠãããããããããç¬ç«ããŠããŸããæåŸã®ãããã ããç°ãªã2ã€ã®ã¢ãã¬ã¹ã¯ãææã®çŽåŸæ¹åã®äž¡ç«¯ã«è¡šç€ºãããå ŽåããããŸãã ã€ã³ã¿ãŒãããäžã§ãšã³ãããŒãšã³ãã®ã¢ãã¬ã¹æå®ã«MACã¢ãã¬ã¹ã䜿çšããããšãçªç¶å§ãŸããšãã«ãŒã¿ãŒã¯ã°ããŒãã«ãããã¯ãŒã¯å ã®åã ã®ããŒãã®ã¢ãã¬ã¹ãç¥ãå¿ èŠããããšããäºå®ã«çŽé¢ããŸãã ããã«ã¡ã¯ãã¢ãã®ã€ã³ã¿ãŒãããã
ããã«çŽ 翻蚳è ã
å ã®èšäºã§åŒ·èª¿ããã質åã¯å®éã«ã¯åçŽãªãã®ã§ã-ã¹ã±ãŒãªã³ã°ã®æ¬ åŠã¯ãã®èããæŸæ£ããã®ã«ååã§ãã
éã®è³ªåã¯ã¯ããã«èå³æ·±ããã®ã§ãããªãMACã¢ãã¬ã¹ãå¿ èŠãªã®ã§ããããïŒ ãã¹ãŠã«ååãªIPã¢ãã¬ãã·ã³ã°ããããŸãããïŒ ããã§ã¯ãã¹ãŠãæ確ã§ã¯ãããŸããã ã¹ã¿ãã¯ã®ååããââãã«TCP / IP /ã€ãŒãµãããã«å€æŽãããL2ã§ã¢ãã¬ã¹æå®ãå®å šã«æŸæ£ãããã»ã°ã¡ã³ãå ã®ããŒããIPãä»ããŠéä¿¡ã§ããããã«ããçŸä»£ã®äžçã§ã¯ã©ãã§ããããã
ARPã¯ããå¿ èŠãããŸãã-ãã±ããã¯IPãä»ããŠäº€æãããŸãïŒãšããã§ãMACåŠç¿ã®ä»£ããã«å®éã«IPåŠç¿ãè¡ãããšãã§ããã¹ã€ãããæ¢ã«ãããŸãïŒã ãããŒããã£ã¹ãã¯ãã¢ãã¬ã¹255.255.255.255ãããå©çšã§ããŸãã
åæã«ãç§ã¯ã€ãŒãµããããL2ãæŸæ£ããããšããŸã£ããææ¡ããŸããããã®ã¬ãã«ã®æœè±¡åãå¿ èŠã§ã-ãããã¯ãŒã¯ã¯ç©ççã«çŽæ¥åäœãããããã¬ãŒãã³ã°ãæŽåæ§ãã§ãã¯ãªã©ãè¡ã£ããããã¹ãã§ã¯ãããŸããã L2ããã¢ãã¬ã¹æå®ãåé€ããã ãã§ãã
å°é£ã¯ããã±ãããäžé£ã®ã«ãŒã¿ãŒãä»ããŠ1ã€ã®ãµããããããå¥ã®ãµããããã«è»¢éããããšãã«å®éã«å§ãŸããŸãã ã€ãŒãµãããã®ãããŒããã£ã¹ãã®æ§è³ªã¯ããã§æããã§ãã IPããããŒã§ã¯ãå®å ã¢ãã¬ã¹ã¯åºå®ãããŠããããã±ãããé²è¡ããŠãå€åããŸããã ãããã£ãŠãã«ãŒã¿ãŒéã§ãã±ãããæ£ãã転éããæ¹æ³ã«ã€ããŠã®çåãçããŸãã çŸåšãNext-Hop MACã¢ãã¬ã¹ãããã«äœ¿çšãããŠããŸãã äºå®ãã«ãŒã¿ãŒã®ã€ãŒãµãããã€ã³ã¿ãŒãã§ã€ã¹ã®èåŸã«ã¯ã1ã€ã®è¿é£ã«ãŒã¿ãŒã§ã¯ãªãã2ã3ããŸãã¯10ãååšããå¯èœæ§ããããããã§ä»ã®Next-hopèå¥åãè¿œå ããå¿ èŠããããŸãã
çŸå®ã®äžçã§ã¯ã99.9ïŒ ã§ã«ãŒã¿ãŒéã®P2Påç·ã䜿çšããŠããããã±ããã«ãã¯ã¹ããããã¢ãã¬ã¹ãè¿œå ããå¿ èŠã¯ãããŸãã-éä¿¡ããçžæã¯ããŸãã-ã±ãŒãã«ã«ãã¬ãŒã ãéä¿¡ããã ãã§ãã ããã§ã¯ãå°ãªããšãæ£åŒã«ã¯ãã¢ãã¬ã¹ããã£ãŒã«ããããPPPãæãåºãããšãã§ããŸãããå®éã«ã¯äœ¿çšãããŠããŸããã
ããããããšããšãŠãŒã¶ãŒãã·ã³ã®ããããŒã«ã«ã»ã°ã¡ã³ãã«å¯ŸããŠã®ã¿èšç»ãããŠããã€ãŒãµãããã®æŠå¿µã¯ãP2Pã·ããªãªãåå¥ã«æäŸããŠããŸããã
ãã®çµæãã€ãŒãµãããã¬ãã«ããã¢ãã¬ã¹æå®ãåé€ã§ããŸããã ãã ããã€ãŒãµãããããããŒã§ã¯Next-Hop IPã¢ãã¬ã¹ã瀺ãããšãã§ãããããMACã¢ãã¬ã¹ã¯äœã§ããããšããçåãæ®ã£ãŠããŸããããã¯åããŒãã§ãå€æŽãããŸãã
äžè¬ã«ãããã¯äºå®ã§ããããã®ã¢ãããŒãã¯ãããã³ã«ã¹ã¿ãã¯ã®ã€ããªãã®ãŒãç Žããã¬ãã«ã®çžäºã®ç¬ç«æ§ãåæãšããŠããŸãã ããã§ãããšãã°ãã€ãŒãµããããç°¡åã«æšãŠãŠã代ããã«xDSLãŸãã¯PONã䜿çšããããã©ã€ããããããã¬ãŒã ãªã¬ãŒã䜿çšãããã§ããŸãããããã¯ç®¡çäžããã³è²¡æ¿äžã®åé¡ã«ãããŸããã ãŸããã€ãŒãµãããäžã§ãç¬èªã®IPCHãããã¯ãŒã¯ãããã³ã«ãæè¡çã«èµ·åã§ããŸããããã¯æå°éã®å€æŽã§æ©èœããŸãïŒæ°ããEthertypeãè¿œå ããŸãïŒã
ãã®åé¡ã¯ãæŽå²çããã³ç®¡ççãªæèããåãé¢ããŠè°è«ããããšã¯ã§ããŸããã çæ³çãªIP +ã€ãŒãµããããããã³ã«ã®å®ç§ãªçµã¿åãããçºèŠãã次ã®300幎ã¯äžççãªå€åã®è åšã«ãããããŠããªããšä»®å®ãããšããŠãã20幎åã«ã¯äžçãç°ãªã£ãŠããããšãèŠããŠããå¿ èŠããããŸãããã äžã€ã ãããã¯ãŒã¯å±€ãšãã£ãã«å±€ãããã»ã©ç·å¯ã«æ¥ç¶ã§ããŸããã§ããã ãããŠä»ããã§ã«æ©èœããŠãããããã¯ãŒã¯ããããŠãã®ããã«ãååãšããŠãã¿ã€ã¿ããã¯ãªåªåãããå¿ èŠã¯ãããŸãããåã«IPã¢ãã¬ã¹ãšMACã¢ãã¬ã¹ãåæã«äœ¿çšããããšã¯åé·ã«æããããã§ãã
ãšããã§ãé©ããããããŸãããã説æãããã¢ã€ãã¢ã®ããã€ãã¯ããªã³ã¯ããŒã«ã«ã¢ãã¬ã¹ã®æŠå¿µãåããIPv6ã®åœ¢ã§ããªããšäžç·ã«ç§ãã¡ã®ç掻ã«å ¥ããŸãã
ïŒQoSã¯åž¯åå¹ ãæ¡åŒµããŸããïŒ
åå¿è ã®éã§ã¯ãQoSãéæ³ã®æè¡ã§ãããåç·ãä»ããŠããå€ãã®ãã±ãããããã·ã¥ã§ãããšèª€è§£ããããšããããŸãã ããã§ã¯ãããŸããã ããšãã°ãã€ã³ã¿ãŒããããã£ãã«ã10Mb / sã«å¶éãããŠããå Žåããã以äžéä¿¡ããããšã¯ã§ããŸããã QoSã®ç®æšã¯ãããã¿ã€ãã®ãã©ãã£ãã¯ãå¥ã®ã¿ã€ãããåªå ãããããšã§ãã ãããã£ãŠãåç·ã®èŒ»èŒ³æïŒ10 Mb / s以äžãéä¿¡ããããšããå ŽåïŒãéèŠåºŠã®äœããã©ãã£ãã¯ã¯ç Žæ£ãããåªå 床ã®é«ãç¡æ転éãåªå ãããŸãã
éåžžãQoSã¯ãé³å£°ããããªäŒè°ãªã©ã®ãªã¢ã«ã¿ã€ã ãã©ãã£ãã¯ããé 延ãæ倱ã蚱容ãããã©ãã£ãã¯ïŒWEBãã¡ãŒã«ãFTPããã¬ã³ããªã©ïŒããä¿è·ããããã«äœ¿çšãããŸãã ããã«ãQoSã¯ããµãŒããŒããã¯ã¢ãããªã©ã®å€§éã®ãã©ãã£ãã¯ã転éããããšã«ããã垯åå šäœã®å æãåé¿ããã®ã«åœ¹ç«ã¡ãŸãã
4Mb / sã®åèšåž¯åå¹ ãæã€2ã€ã®E1ãã£ãã«ãä»ããŠæ¥ç¶ããããªãã£ã¹ãããå Žåã®ç¶æ³ãèæ ®ããŠãã ããã é³å£°ãšããŒã¿ã®äž¡æ¹ããã®åç·ã«æ²¿ã£ãŠéä¿¡ãããŸãã ãã©ãã£ãã¯ã®èŒ»èŒ³äžã«é³å£°ãã©ãã£ãã¯ãå£åããªãããã«ãQoSã䜿çšããŠãä¿èšŒããã垯åãå²ãåœãŠãããšãã§ããŸãã æ®ãã¯ããŒã¿ã«äœ¿çšã§ããŸãã ãã ãããã®åŸããŒã¿ãã©ãã£ãã¯ãèããäœäžããå ŽåãQoSã¯ãã以äžåœ¹ã«ç«ã¡ãŸããããã®å Žåããã£ãã«ãæ¡åŒµããå¿ èŠããããŸãã
翻蚳è ã¯ããã·ã¢èªã®çšèªã§ããã€ãã®èªç±ãèªããŸãããããã«ããã圌ãèããŠããããã«ãæå³ãããããç解ã§ããããã«ãªããŸãã