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ATM³Ì¤jªºÀuÂI«K¬O¦b©ó¨ä¥i¥Ñ¦P¤@Ó¹q¸£¡B¦h¤u¾¹¡B¸ô¥Ñ¾¹¡B¥æ´«¾¹¡Bºô¸ô´N¯à³q¥Î©ó¤£¦P©Ê¯à¡B«~½è©M°Ó·~»Ý¨DªºÀ³¥Î¨t²Î¡C»ÝnATMªº¼u©Ê©M®Ä¯àªºÀ³¥Î¨t²Î¥]¬A¡G(1)¤j²³ªA°È°Ó·~À³¥Î¨t²Î¦p°Ï°ì¡B¼s°ìºô¸ô¤§¶¡ªº¬Û¤¬³sµ²¡B¤j«¬Àɮתº¶Ç¿é¤Î§Y®É¦s¨úÀɮסB®à¤W«¬¹q¸£ªº¦h´CÅéÀ³¥Î¦p¹q¤l¶l¥ó¡B¿ýµ¤Î´CÅé¼½©ñ»P§éÅ|¦¡¥D·F(Collapsed Backbone)ªº®Õ¶éºô¸ôµ¥ªº±±¨î¨t²Î¡C(2)®ø¶O«¬ªA°ÈÀ³¥Î¨t²Î¦p¹q¤l¶l¥ó¤Î¦h«°T®§¨t²Î¡BÀH¿ïµø°TªA°È(Video On Demand¡AVOD)¤Î¤¬°Ê¦¡¹q¤lÀ³¥Î¨t²Î¤Î¹CÀ¸µ¥µ¥¡C(3)¤½²³ªA°ÈÀ³¥Î¨t²Î¦p»·¶Z±Ð¾Ç¡Bµø°T·|ijµ¥µ¥¡C¹Ï3.1¬°ATMºô¸ô¬[ºc¹Ï¡C
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¶Ç²Îªº¸ô¥Ñ¾¹¡A´¿¸g¬O¥ø·~ºô¸ôªº®Ö¤ß²Õ¥ó¡A²{¦bÅܦ¨´£¤É¨ì¤U¤@¥Nºô¸ôªº¥Dn»Ùê¡C¾ãÓÃöÁä´N¦b©ó²Ä¤T¼h¥æ´«¾¹(Layer 3 switch)³Ð³y¤@ÓÄYÂÔªº²Ä¤T¼h¸ô¥Ñ¥\¯à¡A¨ú¥N¥H³nÊ^¬°°ò¦ªº¸ô¥Ñ¾¹¡A¹F¨ì§ó¨³³t¦a¶Ç°e«Ê¥]ªº¥Øªº¡C
²Ä¤T¼h¥æ´«¾¹ªº²£«~¡A¥¦ªº¥X²{»PATM¤Î¥æ´«¾¹¬Û²§ªºI´º¦³Ãö¡A«eªÌ§Æ±æ¼W¥[¸ô¥Ñ¾¹ªº¥\¯à¡A¨Ï¤§¯à°÷¦bMAC¡]Media Access Control¡^¼h¨Ï¥Î¥æ´«¾¹ªº¥\¯à¡A¦P®É¤Sn¥æ´«¾¹¤¤¼W¥[¸ô¥Ñ¾¹ªº¥\¯à¡F«áªÌ§Æ±æ¦bºô¸ô³W¼ÒÅܤj®É¡A¯Â¥Î¥æ´«¾¹ªººô¸ô¯à¤£²£¥Í¼s¼½·¼É¡A¦Ó¥Ñ¸ô¥Ñ¾¹¨Ó¤À¹j©t¥ß¨C¤@ºô¬qªº·¼É¡C¦b³¡¤Àªººô¸ôÀô¹Ò¤U¡A±N¥i¨ú¥N¸ô¥Ñ¾¹ªº³¡¤À¥«³õ¡C²Ä¤T¼h¥æ´«¾¹¨ã¦³¤U¦C´XÓ¯SÂI¡G(1)²Ä¤T¼h¥æ´«¾¹´N¬O¤@³¡¸ô¥Ñ¾¹¡C(2)¥¦ªº¸ô¥Ñ¤¶±¡A»P²Ä¤G¼h¥æ´«»â°ì¬Û¦P¡C(3)¥i¹ê¬I¦³®Äªº¬Fµ¦¹B¥Î¡C(4)ºÞ²z®e©ö¡C¥¦ªº¯S©Ê¬O¥i¥H¹³¶Ç²Îªº¸ô¥Ñ¾¹¤@¼Ë¦a³B²z«Ê¥]¡A¥]¬A¤U¦C¥\¯à¡G(1)®Ú¾Ú²Ä¤T¼h¸ê°T¨M©w«Ê¥]«e¶i¸ô®|¡C(2)³z¹L¦ì¤¸¥[Á` (checksum)§Þ³N½T»{²Ä¤T¼h¼ÐÀYªº§¹¾ã¡C(3)ÃÒ¹ê«Ê¥]²×µ²©M§ó·s¡C(4)³B²z©M¦^À³¥ô¦ó¿ï¾Ü¸ê°T¡C(5)§ó·s¶Ç°e²Îp¸ê®Æ©óºÞ²z¸ê°T®w¤¤¡A¨Ã¥B¦b¥²n®É¹ê¬I¦w¥þºÞ¨î±¹¬I¡C
²Ä¤T¼h¥æ´«¾¹¥Dn³]p¨Ó³B²z°ª®Ä¯àªº°Ï°ìºô¸ô¥æ³q¬y¶q¡A©Ò¥H¥¦¥i¥H³Q©ñ¸m¦bºô¸ô®Ö¤ß©Î¥D·Fªº¥ô¦ó¦a¤è¡A¨Ã¥B«Ü»´©ö¤Î¸gÀÙ¦a´À´«¶Ç²Î§éÅ|¦¡¥D·F¤Wªº¸ô¥Ñ¾¹¡C²Ä¤T¼h¥æ´«¾¹¨Ï¥Î¹³RIP©MOSPFµ¥¤u·~¼Ð·Çªº¸ô¥Ñ³q°T¨ó©w¡A¥i¥H©MWAN¸ô¥Ñ¾¹¥æ´«°T®§¡C²Ä¤T¼h¥æ´«¾¹ªº¨CÓ¤¶±¥ý¤Ñ¨ã¦³²Ä¤G¼h¥æ´«»â°ì(Layer 2 switching domain)¡A¤¹³\¤À°tÓ§O¤lºô¸ôÀW¼e¡A¦ñÀHµÛ¹ïºô¸ô¼s¼½ªº¹jÂ÷¯à¤O¡C¥¦¥i¥H®Ú¾Úª«²zªº¯S©Ê©Î³q°T¨ó©w¸ê°T¥h²Õ´¤£¦Pªº¿é¥X¤J°ð¸s²Õ¡A³oºØ¯à¤O¡A¹ïºô¸ô³]pªÌ¦Ó¨¥¡A¦bºô¸ô®e¶q³W¹º³]p¤W¬O¤@Ó¶W±jªº¤u¨ã¡C³oºØµ²ºc¤Ñ¥Í¨ã¦³ÂX¥R¼u©Ê¡A¯à°÷¤ä´©·¥¦hªº²Ä¤G¼h¥æ´«¾¹¡A¤£½×¥¦Ì¬O¾n¦b¸ê®Æ¤¤¤ß©ÎªÌ¦b½u¸ô¾÷ÂdùØ¡C³o¼Ëªº³]p¼Ò«¬«O¦s¤F¤lºô¸ôªº°ò¦ºc³y¡A¦P®É´£¤É¤lºô¸ôªº©Ê¯à¡A¦Ó¥B¯à°÷¦b¥²n®É¥¬¸p¥æ´«¦¡ªº10¡B100©Î1000 MbpsªºÀW¼e¦Ü®à¤W«¬¤u§@¯¸¡C«O¯d¤lºô¸ôªº·§©À¬O«P¨Ïºô¸ô²¾´Ó¦¨¥\ªºÃöÁä¡A¦]¬°¥¦¤¹³\³vº¥ªº¾E²¾¡AÀ°§Uºô¸ô³]pªÌ»P¦P¹±¶È¦b³¡¥÷³]³Æ¤W¶i¦æ³]©w§Y¥i¡A¦Ó¤£¥²«·s½s¸¹»P³]©w¥þ³¡ªººô¸ô¡C
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3.6 Gigabit Ethernet
Gigabit Ethernet¬O¬Û·í¦¨¥\ªº10 Mbps©M100 Mbps IEEE 802.3 Ethernet ¼Ð·Çªº©µ¦ù[5]¡C´£¨Ñ1000 Mbpsªºì©l¸ê®ÆÀW¼e¡A Gigabit Ethernet»P Ethernet ¸`ÂIºû«ù§¹¾ãªº¬Û®e©Ê¡CGigabit Ethernet¤ä´©¥æ´«¾¹»P¥æ´«¾¹¶¡(switch-to-switch)¤Î¥æ´«¾¹»P²×ºÝ¤u§@¯¸(switch-to-end-station)¶¡·sªº¥þÂù¤u¾Þ§@¼Ò¦¡¡A¨Ã¥B¤ä´©¨Ï¥Î¼W±j¾¹©MCSMA/CD¦s¨ú¤èªkªº¤À¨É³s±µ±Ä¥Î¥bÂù¤u¾Þ§@¼Ò¦¡¶i¦æ¡C³Ìªì¾Þ§@±Ä¥Î¥úÅÖ§@´C¤¶¡AGigabit Ethernet ±N¦P®É¤]¯à°÷¨Ï¥Î²Ä¤ÃþµL¾B½ªÂùµ±½u¤Î¦P¶b¹qÆl½u§@´C¤¶¡C
¨Ï¥Î¤w¦s¦b¡A²{¦¨¥i¥Îªº¡A¸gÃÒ¹ê¥i¥Îªº§Þ³N©M¤èªk¡A¥iÁYµuGigabit Ethernet ²£«~ªº¤W¥«®É¶¡¡C©ó1998¦~6¤ë¨î©w§¹¦¨ªºIEEE 802.3z¼Ð·ÇµÛ¤O©ó¨Ï¥Î¥úÅÖ³q¹D©M¨ä¥Lªº°ª³tºô¸ô¹s²Õ¥ó¡C¥úÅÖ³q¹D½s½X/¸Ñ½X¿nÊ^¹q¸ô©M¥ú¾Çªº¹s²Õ¥ó¬O¤w¸g²{¦¨¥i¥Îªº¡A¨Ã¥B¦b¬Û¹ï§C¦¨¥»¤U¥i¥H³Q³]©w©M³Ì¨Î¤Æ¥H¹F¨ì°ª®Ä¯à¡CGigabit Ethernet³Ìªìªº«Ø¸m±N±Ä¥Î°ª³t¥úÅÖ³q¹D¡A780-nm¥ú¾Çªº¹s²Õ¥ó§@¬°«H¸¹¶Ç¿é´C¤¶¡A¥H¤Î¨Ï¥Î8B/10B½s½X/¸Ñ½X¬[ºc§@¬°§Ç¸¹½s½X©M§Ç¸¹¸Ñ½X¡C²{¦b¥úÅÖ³q¹D§Þ³N¥i¥H±q1.063Gbpsªº¾Þ§@³t²v¼W±j¦Ü1.250Gbps¡A¦]¦¹¥i¥H¨ÑÀ³§¹¾ãªº1000M bps¸ê®Æ¶Ç¿é²v¡C¬°³sµ²¸ûªø¶ZÂ÷¡F¨Ï¥Î³æ¼Ò¥úÅÖ¥i¹F¨ì¦Ü¤Ö2¤½¨½¡A¨Ï¥Î62.5·L¦Ìªº¦h¼Ò¥úÅÖ¥i¹F¨ì¦Ü¤Ö550¤½¤Ø¡F1300-nm ªiªø¥ú¾Ç¦P®É¤]±N³Q±Ä¥Î¡C
Gigabit Ethernetªºªì´ÁÀ³¥Î±NÂê©w©ó¶é°Ï©Î¤j¼Óºô¸ô¡A¥Î¨Ó´£¤É¸ô¥Ñ¾¹¡B¥æ´«¾¹¡B¶°½u¾¹¡B¼W±j¾¹¤Î¦øªA¾÷¤§¶¡ªºÀW¼e¡A¹w³]ªº¨Ò¤l¥]¬A¥æ´«¾¹»P¸ô¥Ñ¾¹¡B¥æ´«¾¹»P¥æ´«¾¹¡B¥æ´«¾¹»P¦øªA¾÷¤Î¼W±j¾¹»P¥æ´«¾¹µ¥¥|ºØ³s±µ¬[ºcªºÀW¼e´£¤É¡CGigabit Ethernet ©|¥¼¦Ò¼{©µ±µ¦Ü¤@¯ëªº®à¤W«¬¹q¸£¤W¡CGigabit Ethernet »P²{¦³Ethernet©Ý¾ëªº§G½u¶ZÂ÷¨î¤ñ¸ûªí¦pªí¤G¡C
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Ethernet10 Base-T |
Fast Ethernet100 Base-T |
Gigabit Ethernet Goals1000 Base-X |
¸ê®Æ¶Ç¿é²v |
10 Mbps |
100 Mbps |
1000 Mbps |
Cat 5 UTP |
100 m(min) |
100 m |
100 m |
STP/Coax¡@ |
500 m |
100 m |
25 m |
Multi-mode Fiber |
2 km |
412 m(hd)**2 km(fd)* |
500 m |
Single-mode Fiber |
25 km |
20 km |
3 km |
**IEEE spec ¥bÂù¤u(half duplex)
* IEEE spec ¥þÂù¤u(full duplex)
4. ºô¸ô¬[ºcµû¦ô
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4.2.1 MPOA¬[ºc
¦p«e¤@³¹©Ò¤¶²Ð¡A¥»©ÒY±Ä¥ÎMPOA¬[ºc®É¡A¬O¥H²{¦³¸ô¥Ñ¾¹©MATM¥æ´«¾¹¬°¥D¡A±N즳ªº¸ô¥Ñ¾¹°h©~I«á¡A¥HÃä½t¥æ´«¾¹¨ú¥N¡C¦¹¬[ºc¥Dn¬O¥HATM forum©Ò»sqªº¼Ð·Ç¬°®Ö¤ß¡A¬OATMºô¸ô¸Ñ¨Mºô¸ô¼h¸ô¥Ñ¥æ´«ªº³Ì·s¬[ºc¤§¤@¡A¥¦¥i¥H²Å¦X¤U¤@¥Nºô¸ôªº»Ý¨D¡C·í¤@¸ê°T«Ê¥]¶i¤Jºô¸ô®É¡A¥ý¨ì¸ô¥Ñ¾¹¨ú±o©Òn³s½uªº»·ºÝ¦ì§}¡AÀH§Y«Ø¥ßVPI/VCI¸ô®|¡A¦Ó©¹«á¶Ç°eªº¤u§@´N¥æ¥ÑÃä½t³]³Æ°õ¦æ¡A¥H¸Ñ¨M¸ô¥Ñ¾¹¡yÀx¦s»P¶Ç°e¡zªº¯ÊÂI¡C¥»©ÒY±Ä¥Î¥»¬[ºc¡A·|²£¥Í¦p¤U´XÂI°ÝÃD¡G1.MPOA¼Ð·Ç¤§»sq¬O¦b1997¦~9¤ë¤~§¹¦¨¡A±N¶·¤@¬qªø®É¶¡ªº¥Í²£´Á¤Î´ú¸Õ´Á¡A¦Ó¥B¬O§_·|¦³¦¹Ãþ²£«~¥X²{¡A¯à§_©ó1998¦~3¤ë«e¥¿¦¡¥X²£¡A¤´¬OÓ¥¼ª¾¼Æ¡F2.¬J¦³¸ô¥Ñ¾¹¤´»Ýt³droutingªº¥ô°È¡A¨ä³s½u³t«×©|µLªkº¡¨¬¥»©Òºô¸ôªº»Ý¨D¡F3.¬[ºc²~ÀV¡G¸ô¥Ñ¾¹ªº³B²z¾¹©MIªOªº®Ä¯à¤£¨¬¡C
MPOAÁö¬°ATM Forum©Ò©w¸qªººô¸ô¼Ð·Ç¨ó©w¡AµM¦Ó¡A¦]¬°MPOA©ó1997¦~9¤ë©l¥¿¦¡§¹¦¨¼Ð·Ç¨î©w¡A¦Ó¥»©Ò²Ä¤T´Áºô¸ô¨ä®É¥¿³B©ó³W¹º§@·~¶¥¬q¡A¬O§_·|¦³¥¿¦¡MPOA²£«~°Ý¥@¡A¤´¤£±o¦Óª¾¡C¦]¦¹¥»¬[ºc¶È©ó¾Ç³N©Ê¤§±´°Q¡C¦ý²Ä¤T´Áºô¸ô³W¹º¨ü¦¹¬[ºc¼vÅT¬Æ²`¡A¦]¬°´£ª@ºô¸ô®Ä¯à¡A¨Ã¾É¤J·s¤@¥Nºô¸ô§Þ³N¬O²Ä¤T´Á³W¹º¥Ø¼Ð¤§¤@¡C
¹Ï4.1 ²Ä¤T´Á©Ò°Ïºô¸ô¬[ºc¹Ï¤@(MPOA)
4.2.2 Fast Ethernet
¥»©Ò³W¹ºªº²Ä¤GÓºô¸ô¬[ºc(¦p¹Ï4.2)¬O¥HFast Ethernet¬°¥D¡A¦b¬J¦³¤³¡¸ô¥Ñ¾¹¤U¦U¥[¸Ë¤@ÁûÃä½t³]³Æ¡A¨C¤@ÓÃä½t³]³Æªº³s±µ°ð§¡¥i°õ¦æ10/100 Mbps¡A¨Ã¦³¤@Ó¨ã100 Mbps¶Ç¿é¯à¤O¡A¥i¥H°õ¦æ¥þÂù¥\200 Mbps¤§Fast Ethernet³s±µ°ð³s±µ¦Ü¸ô¥Ñ¾¹¤W¡C°w¹ï±j¤Æ«n¥D¦øªA¾÷¤§³s½u¥\¯à¡A¦]Ãä½t³]³Æ¨ã¦³ATM¤§³s±µ¤¶±¡A¨Ï¦øªA¾÷¤§ºô¸ô¼ÒÀÀ(LAN Emulation¡ALANE)³æ¯Â¤Æ¡A®e©öºÞ²z©MºûÅ@¡F¦¹Ãä½t³]³Æ¨ã¦³¨ú¥N©M³Æ´©ATM¥æ´«¾¹¤§¥\¯à¡AÃä½t³]³Æ©MATM¥æ´«¾¹¤¤¶¡¨Ã¦³³Æ´©Âù³s½u¡A¥H¼W¶iºô¸ô¤§Ã©w©Ê¡C¦ý¥»¬[ºc¦³¦p¤U´X¶µ¯ÊÂI¡G1.¥»¬[ºcªº©¹«áºô¸ôÂX¥R±N¨ü¨î©ó¬J¦³¸ô¥Ñ¾¹¥»¨ªºÂX¥R¯à¤O¡F2.¬[ºc²~ÀV¡G¸ô¥Ñ¾¹ªº³B²z¾¹©MIªOªº®Ä¯à¤£¨¬¡C
¹Ï4.2 ²Ä¤T´Á©Ò°Ïºô¸ô¬[ºc¹Ï¤G(Fast Ethernet)
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4.2.3 Layer 3 ¥æ´«
¥»©Ò¸g¤Wz¤GºØºô¸ô¬[ºc¤ÀªR¤ñ¸û«á¡A±o¨ìªºµ²½×¬O¡G»P¨ä§ë¸ê¦b±N±Á{²^¨Oªº¸ô¥Ñ¾¹¤W¡A¤£¦p±Nºô¸ôªº¥D·F¥þ³¡±Ä¥Î¨ã¸ô¥Ñ¥\¯àªº¸ô¥Ñ¥æ´«¾¹¤§²Ä¤T¼hºô¸ô¬[ºc(¦p¹Ï4.3)¡C¦]¬°±Ä¥Î¥»¶µ§@ªk¡A¤£¶È¥i±o¨ì§ó¨Îªººô¸ô®Ä¯à¡A¥ç¯àº¡¨¬¤é«áºô¸ôÀô¹Òªº´£ª@»Ý¨D¡C¥»¬[ºc¬O±N¬J¦³ªº¸ô¥Ñ¾¹¥þ³¡¥H¨ã¦³routing¥\¯àªº¥æ´«¾¹¨ú¥N¡A¨ä¤¤¤@³¡¥æ´«¾¹¨Ã¨ã¦³ATM¤¶±¡C¸g¦h¤è¤F¸Ñ¡A¦¹¬[ºc¤w¦³¬Y¨Ç³æ¦ì±Ä¥Î¡A¬[ºc²³æ»PºÞ²z®e©ö¬O¨ä¥DnÀuÂI¡CµM¦Ó¡A¥»¬[ºcªº®Ö¤ß¾÷¾¹(Cisco Light-Stream 1010 ATM ¥æ´«¾¹)¦p¦ó©M¶gÃ䪺²Ä¤T¼h¥æ´«¾¹¤¬³q¬O©Ò±Á{ªº¥t¤@°ÝÃD¡A¦Ó¥B¬J³]ªº¸ô¥Ñ¾¹±ó¤§¤£¥Î¡A¥i¯à³y¦¨¸ê·½ªº®ö¶O¡A¥ç¬O¦³«Ý°Óºe¡C
¹Ï4.3 ²Ä¤T´Á©Ò°Ïºô¸ô¬[ºc¹Ï¤T(Layer 3)
4.2.4 Layer 3 ¤ÎATM¾ã¦XÂù³Æ´© (Layer 3 with ATM switching)
«e¤@¬[ºc¤w´x´¤·s¤@¥Nºô¸ô§Þ³Nªºµo®i¡A¦ý¤´¤£¯àº¡¨¬¥»©Ò²{¦³Àô¹Òªº»Ý¨D¡C²Ä¥|ºØºô¸ô¬[ºc¬O«e¤@¬[ºc¤§§ï¶i¡A§Y¦b©Ò¤º¼W«Ø¤@ӲĤT¼h¥æ´«¾¹ªº¿W¥ß¥Dºô¸ô¡A¨C¤@¥æ´«¾¹©M즳ºô¸ô¤§ATM¤Î¸ô¥Ñ¾¹§¡¬Û¤¬³Æ´©³s±µ¡A¨Ï¦¨¬°Mesh¤§ºô¸ô¬[ºc¡A±Ò°ÊPNNI¤ÎOSPFµ¥³q«H¨ó©w¡A¥H¹F¨ì¨â§¹¥þ¬Û¤¬³Æ´©ºô¸ô¤§¥\¯à(¦p¹Ï4.4)¡F¥»¬[ºcÀuÂI¬°¥ô¦ó¤@ºô¬q¬G»Ù¡A§¡¥i«Ø¥ß¥t¤@³s³q¸ô®|¡A¥ç¥i§JªA«e¬[ºc¤£¤@P©Ò³y¦¨ºûÅ@¤£©ö¤§§xÂZ¡F¨C¤@Ãä½t³]³Æ¦p¨ã¦³routing¥\¯à¡A«h¥i±Nºô¬q¤Á³ÎÀu¥ýµ¥¯Å¡Cºî¦X¥H¤W¥|ºØ¬[ºcªº³]p¦Ò¶q¡A¥H²Ä¥|ºØ¬[ºc³Ì²Å¦X¥»©Òºô¸ô¤§»Ý¨D¡A¨ä²z¥Ñ¦p¤U¡G
¹Ï4.4 ²Ä¤T´Á©Ò°Ïºô¸ô¬[ºc¹Ï¥|(Layer 3 with ATM)
4.3 ³q«H¨ó©w
±ýº¡¨¬Layer 3¤ÎATM¾ã¦XÂù³Æ´©ºô¸ô¨t²ÎÀô¹Ò¡A¤£¦Pªº¼t®a²£«~¶¡ªº³q«H¨ó©w¶¡¤§¬Û®e©Ê¡A¹ï¥»©Ò²Ä¤T´Áºô¸ô¬[³]ªº¦¨±Ñ¡A¨ã¦³ÃöÁä©Êªº¼vÅT¡C¥»©Ò²Ä¤T´Áºô¸ô¬[³]¹Lµ{¤¤¡A³z¹L¹ï·s¤@¥Nºô¸ô§Þ³Nªº¤F¸Ñ»P´x´¤¡A¬ð¯}¤£¦P¼tµP¶¡ATM¥æ´«¾¹ªº¬Û®e³q«H¨î¡A¥Dn¬O¦¨¥\ªº±Ò°Ê¤F¥H¤U´X¶µ³q«H¨ó©w¡A¤Àz¦p¤U¡C
4.3.1 PNNI(Private Network to Network Interface)
¦b¥»©Òªººô¸ô¸Ì¡A¤£¦P¼tµPªºATM¥æ´«§Þ³N¤¤³Ì«nªº¬OPNNI Àô¹Ò³]©w¡APNNI¬OATM©MATM©ÎATM©M²Ä¤T¼h¥æ´«¾¹¶¡·¾³q¤§©³¼h³q«H¨ó©w¡C©úÅã¦a¡A¥»©ÒªºATM¥æ´«¾¹ºô¸ô¤Î²Ä¤T¼h¥æ´«¾¹ºô¸ô¶¡·¾³q³Ì«nªº¤¸¥ó¤§¤@¬°PNNI¤§³q«H¨ó©w¡C
PNNI¬OATM Forum5©Òq¤§ATM°T¸¹(Signaling)¤Î¸ô¥Ñ(Routing)¤§¼Ð·Ç[6¡A7]¡A¥¦¦³¥|Ó¥Dn¥Ø¼Ð¡G1.¨ÏATMºô¸ôºÞ²z§ó²³æ(Simplicity)¤Î§ó¨ã¦³¼u©Ê(Flexibility)¡F2.¨ÏATMºô¸ô¨t²Î§ó¨ã¦³ÂX¥R©Ê¡F3.¨ÏATMºô¸ô°õ¦æ§ó¦³®Äéwªº¸ô¥Ñpºâ¡A¨Ãº¡¨¬ATM-QoSªº»Ý¨D¡F4.¨Ïºô¸ô¤§Àô¹Ò³]©w§ó²©ö¤Î¯à¦Û°Ê×§ïºûÅ@ºô¸ôÀô¹Ò°Ñ¼Æ¡C
³s±µ¤G³¡¤£¦P¼tµPªºATM backbone Switch¤§¨ó©w¦³IISP¤ÎPNNI¡A¨âªÌ³Ì¤jªº¤£¦PÂI¦b©óIISP¥u´£¨ÑÀRºA¸ô¥Ñ(static routing)¥\¯à¡A¦ÓPNNI«h´£¨Ñ°ÊºA¸ô¥Ñ(dynamic routing)¥\¯à¡CIISPÀRºA¸ô¥Ñªº¯ÊÂI¬°¡Ga.³]©wÁcÂø¥B©ö²£¥Í¿ù»~¡Ab.µLªk´£¨Ñ³Æ´©(back-up)¯à¤O¡F¬Û¤Ïªº¡A¥Ñ©óPNNI±Ä¥Î°ÊºA¸ô¥Ñ¡A¥i¥H¦Û°Ê¸g¥Ñ³nÅé¿ï¾Ü³Ì¨Î¸ô®|¡A¦]¦¹¦b¬Y¤@¸ô®|Â_½u®É¡A¥i¥H¦A¿ï¾Ü¥t¤@³Ì¨Î¸ô®|¡A¹F¨ì¦Û°Ê³Æ´©¥\¯à¡C
¥»©Ò²Ä¤G´Áºô¸ô±Ä¥ÎCisco ATM¥æ´«¾¹¡A²Ä¤T´Áºô¸ô«h±Ä¥ÎXylan ATM¥æ´«¾¹¡A¦¹¤G¨t²Î¤¬°µ³Æ´©¡A¦]¦¹PNNIªº³]©w¬O³Ì¥Dnªº§Þ³NÃöÁä¡C
4.3.2 ELAN(Emulated LAN)
ELAN(Emulated LAN)¬OATM LAN Emulation¨ó©w¤¤¥²³Æªº§Þ³N[8]¡A¨ä¥Øªº¦b¾ã¦X¬J¦³ªººô¸ô¨ó©w¤Î³]³Æ¡C¶Ç²Îªººô¸ô§Þ³N±Ä¥Î«Ê¥](packet)¡A¨Ò¦pEthernet¡AToken Ring¡A¤ÎFDDI¡A¦ÓATM«h±Ä¥ÎCell¡A¨âªÌ¤§¶¡µLªkª½±µÂà´«¡F¦³«Ê¥]ªº¨C¤@Ó¸`ÂI(node)¦b³s±µATM³]³Æ®É¡A¥²¶·½T»{¨ä©ÒÄݪºELAN¡A¤~¯à¶¶§Q¦a¦bATM¥æ´«¾¹¤¤¶Ç¿é¡F·í¸ê®Æ¶Ç¿éªº°_©lÂI(source)»P¥Øªº¦a(destination)ÄÝ©ó¦P¤@ÓELAN®É¡AATM¥æ´«¾¹´N¥H¥æ´«ªº¤è¦¡¶Ç¿é¡A·í°_©lÂI»P¥Øªº¦a¤ÀÄݤ£¦PELAN®É¡A´N¥²¶·É§Uroutingªº¤è¦¡¨Ó¶Ç¿é¡C
²¨¥¤§¡AELAN´NÃþ¦ü¶Ç²Î¸ô¥Ñ¾¹ºô¸ô¤¤¤lºô¸ô(subnet)ªºÆ[©À¡A¦bIP©ÎIPXªºÀô¹Ò¤¤¡A¨C¤@Ó¸`ÂI¤@©w¬OÄÝ©ó¬Y¤@Ó¤lºô¸ô©Î¬Y¤@Óºô¬q(segment)¡A¦p¦¹¸ô¥Ñ¾¹¤~¯à¥¿½Tªº§ä¨ì¨C¤@Ó¸`ÂI¡A¦bATMªºÀô¹Ò¤¤ELANªº³]p´N¬O¬°¤FÅýATM¥æ´«¾¹¯à¥¿½T¥B¨³³tªº§ä¨ì¨C¤@Ó¸`ÂI¡C
¥»©ÒªºATM¤Î²Ä¤T¼h¥æ´«¾¹¨â¥Dºô¸ô¬[ºc¤¤¡ACisco ¤§ATM¤¤ELAN¤ÎVLAN¶¡¨ÃµL¤j®t§O¡A¦ý¦b²Ä¤T¼h¥æ´«¾¹¤¤ªºELAN©MVLAN¤§¥\¯à«h¦³©úÅ㤣¦P¡CATM¬Ocellªº§Þ³N¡A¦pªG§ÚÌn¦bCell-basedªºATM¥æ´«ºô¸ô¤¤º¡¨¬LAN¤§¥\¯à¡A¥²»Ý¸g¥ÑELAN¼ÒÀÀLAN¦bcell-based¤§¤Wªº°Ê§@¡C¦]¬°¦b¥»©Ò¨Ï¥Îªººô¸ô³q«H¨ó©w¡A°£¤F»Ýº¡¨¬¯ÂIP¤§¥~¡A©|»Ýº¡¨¬NetBios¡BIPX¤ÎµêÀÀ½u¸ô»yµ¶Ç¿éµ¥¤£¦P¤§¶Ç¿é¥\¯à¡A¦Ó±Ò°ÊELAN¬O¸û¨Îªº¿ï¾Ü¡C
¦b¶Ç²Î¸ô¥Ñ¾¹¬[ºc¤¤¡A¸Ñ¨M¸ó¶Vºô¬q°ÝÃDµLªkª½±µ¥H²Ä¤G¼h¥æ´«¾¹©Î¶°½u¾¹¤è¦¡³s±µ¡A¤£¦Pªººô¬q¶¡¡A¥²¶·¥H¥úÅÖ©ÎUTPµ¥¦ê±µ¡AºÞ²z¤£©ö¡A©ö³y¦¨¥úÅָ귽®ö¶O¡C·s¤@¥Nºô¸ô¥æ´«§Þ³N¤¤ªºELAN¡A¥i¸Ñ¨M¥H©¹¸ó¶Vºô¬q¤§§xÃø¡C¹Ï4.5¬°¥»©ÒELANÅÞ¿è¬[ºc¹Ï¡A¹Ï¤¤¦@«Ø¥ßelan_60¡Belan_21¤Îelan_iner¤TÓELAN¡A¨ä¤¤elan_21¬°¥»©Ò¹ï¥~³s½u¤§ºô¬q¡A¬°§ï¶i¥H©¹¦ê±µªº¯ÊÂI¡A³]©wELAN¤§«á¡A©Ò¦³ÄÝ©ó192.192.21.0ºô¸ô»â°ìªº«Ê¥]§Y¥i¦b¦¹ELAN¤W¶Ç¿é¡C
¹Ï4.5 ¥»©ÒELANÅÞ¿è¬[ºc
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4.3.3 VLAN(Virtual LAN)
¦b¶Ç²Îªº¸ô¥Ñ¾¹/¥æ´«¾¹/¶°½u¾¹ºc¦¨ªººô¸ô¤W¡A¦P¤@¼s¼½ºô°ì(Broadcast domain)³£¬O¥ÑµwÅé¨Ó²Õ¦¨¡A¨Ò¦p¡G¦P¤@³¡¥æ´«¾¹©Î¶°½u¾¹¥²©wÄÝ©ó¦P¤@Ó¼s¼½ºô°ì¡A¦Ó¦b¦P¤@Ó¼s¼½ºô°ì¤U¡A¦P¤@Ӯɶ¡¥u¯à¦³¤@Ónode¶Ç°e¸ê®Æ¡C¤£¦Pªººô¬q¤@©wn³z¹L¸ô¥Ñ¾¹¤~¯à¤¬³q¸ê®Æ¡A³o¼Ëªº¬[ºc²£¥Í¥H¤Uªº¯ÊÂI¡Ga.ºô¬qªº¹º¤À¨ü©ó¥æ´«¾¹¤Î¶°½u¾¹ªºµwÅé¨î¡Fb.§Q¥Î¸ô¥Ñ¾¹¨Ó¹º¤Àºô¬qÄY«¹HI¨Ï¥Î¥æ´«¾¹ªºì©l¥Øªº¡A¨Ï¥Î¥æ´«¾¹¬O¬°¤FÁYµu¶Ç¿é®É¶¡¡A¦ý¸ô¥Ñ¾¹«h¦³«Üªøªº©µ¿ð®É¶¡(latency)¡CVLANªº³]p¬O¨Ï¥Î³nÅ骺¯à¤O¨Ó¨ú¥NµwÅ鹺¤À¼s¼½ºô°ìªº¨î¡A¥H´£°ª¥æ´«¾¹¹º¤Àºô¬qªº¯à¤O¤Î¨Ï¥Î®Ä¯à¡C
¥»©Ò¦bLayer 3¤ÎATM¥æ´«¾¹¶¡±Ò°ÊµêÀÀºô¸ô[9](VLAN)¸Ñ¨M¤Wzªº°ÝÃD¡AVLAN¬O¥HELAN¬°°ò¦¡A§Ų̨́ϥΪ̩Τu§@Àô¹Ò¤§»Ý¨D¡A±NELAN¦A¤©¤Á³Î¬°¤£¦PªºVLAN¡A¨C¤@VLAN¦³¤@ÓµêÀÀ¸ô¥Ñ¾¹t³dºÞ²z¦¹VLAN«Ê¥]¶Ç°e¤Î¼s¼½¡CVLAN§JªA¶Ç²Î¸ô¥Ñ¾¹/¥æ´«¾¹ªº¥ý¤Ñ¤W¨î¡A´£¨Ñºô¸ô¤W¨Ï¥ÎªÌ¸s²Õ©ó¤£¦Pºô¸ô©Îºô¬q¯à±µ¨ì¦P¤@¸s²Õªº¼s¼½«Ê¥]¤§¥\¯à¡C²{¦³VLAN³]©w¥i¨Ìºô¸ôºÞ²z»P¨Ï¥Î»Ý¨D±Ò°Ê¡GPort-based virtual LANs¡AMAC address virtual LANs¡ALayer 3¡AProtocol policy virtual LANs¡A¡Kµ¥µêÀÀºô¸ô¥\¯à¡A¨Ïºô¸ô³]©w§ó¨ã¦³¼u©Ê¡C
¹Ï4.6¬°¥»©ÒVLANÅÞ¿è¬[ºc¹Ï¡A¥»©Ò¾Ö¦³6Óclass C¤§ºô¬q¡A¦Ó©Ò±Á{ªº¬O³o¨Çºô¬q¸g¥Ñ¸ô¥Ñ¾¹¤Á³Î¦¨¤£¦P¤j¤pªº¤lºô¬q¡A³y¦¨¸ô¥Ñ¾¹ªº¸ô®|ªíºÞ²z¸û½ÆÂø¡A¶i¦Ó¼vÅT¸ô¥Ñpºâªºt²ü¡A¦P®É¥ç³y¦¨ºô¸ô¼s¼½ªº°ÝÃD¡A³]©wVLAN¥i¸Ñ¨Mºô¬q¤Á³Î¤Î¼s¼½ºô°ì¤§°ÝÃD¡C¹Ï¤¤ATM uplink¬°Elan ¤§³s½u¸s²Õ¡A¦ÓELAN¸s²Õ¤º¦A¹º¤À Vlan1¡BVlan2¡BVlan3...µ¥¤£¦PIP¤lºô¬qVLAN ¨Ó´£¨Ñ³s±µ¥~À]³s±µ¤§¹B§@¡A²Ä¤T¼h¥æ´«¾¹¤º³¡±Ò°ÊµêÀÀ¸ô¥Ñ¾¹¥\¯à¡A±NIP±Ò°ÊOSPF¤§¹B§@¡A°t¦X¬J³]¸ô¥Ñ¾¹ºô¸ô¶i¦æºô¸ô¸ô¥Ñ¤§¹Bºâ¡A¥i´î¤Öºô¬q¤§®ö¶O»PÁY¤p¼s¼½»â°ìªº½d³ò¡A´£ª@ºô¸ô¤§®Ä¯à¡C
¹Ï4.6 ¥»©ÒVLANÅÞ¿è¬[ºc¹Ï
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4.3.4 OSPF(Open Shortest Path First)
¥»©Òì¥ý¨Ï¥ÎRIPªº°ÊºA¸ô¥Ñ¨ó©w¡A¦¹¨ó©wªººtºâªk(algorithm)¬Opºâ°_©lÂI¨ì¥Øªº¦aªºhop¼Æ¡A¦Ó¿ï¾Ü¤@±øhop¼Æ³Ì¤Öªº¸ô®|¡C®Ú¾Ú¦¹¤@¤èªk«Ø¥ß¸ô¥Ñ¾¹¤ºªº¸ô®|ªí¡A¨Ã±N¦¹¸ô®|ªí¨C30¬í»P¨ä¥L¸ô¥Ñ¾¹¥æ´«¡A¤]´N¬O¨C30¬í¸ô¥Ñ¾¹·|¤¬¬Û¼s¼½¸ô®|ªí¡A¦pªGºô¸ô¤º¦³NÓ¸ô¥Ñ¾¹¡A«h¨C30¬í¤ºªº¼s¼½¦¸¼Æ´N¬ON¦¸¡C¦b¤j«¬ªººô¸ô¤º¡ARIPªº¼s¼½ÅãµM·|¦û¥Îºô¸ô¤Ó¦hÀW¼e¡A¶i¦Ó°§Cºô¸ôªº¨Ï¥Î®Ä¯à¡A©Ò¥HRIP¾A¥Î©ó¤p«¬ªººô¸ô¤¤¡C
OSPF[10]¬°¿ï¾Ü³Ì¨Î¸ô®|ªº¸ô¥Ñ³q«H¨ó©w¡A¨ã¦³°ÊºA¸ô®|¿ï¾Ü¯à¤O¡A¥¦·|®Ú¾Ú¨C¤@Ó¸ô®|ªº¸ê®Æ¬y¶qµ¹¤©¨C¤@Ó¸ô®|¤@Ó¥[ÅvÈ¡A¦A®Ú¾Ú°_©lÂI¦Ü¥Øªº¦aªº¦UÓ¸ô®|Á`¥[ÅvȨӿï¾Ü¤@ӳ̵u¸ô®|¡C¦Ó¥BOSPFªº¸ô®|ªí¥u¦s¦b¤@Ó¥D¸ô¥Ñ¾¹(master router)¡A¥D¸ô¥Ñ¾¹t³d¼s¼½¸ô®|ªíµ¹¨ä¥L¸ô¥Ñ¾¹¡A©Ò¥H¦b©T©w®É¶¡¤º¥u·|¦³¤@¦¸ªº¼s¼½¡A¦Ó¤£¹³RIP¦³N¦¸¼s¼½¡F©Ò¥H¤ñ¸û¾A¥Î©ó¤j«¬ºô¸ô¡C
¥»©Ò²Ä¤G´Á¤uµ{®É¡A±Ä¥Îªº¬O¬Pª¬¬[ºc¥D·F½u¡A¦]¦¹¡A¦b¸ô¥Ñ¿ï¾Ü®ÉRIP³q«H¨ó©w¤w¥i§¹¥þ±±¨î«Ê¥]ªº¶Ç°e¡C¦ý·í«Ø¸m²Ä¤Gºô¸ô¥D·F®É¡Aì¥ýCisco´£¨ÑªºRIPµLªk¤ä´©¦s¦bloopºô¸ô¬[ºcªº¸ô¥Ñ¹Bºâ¡AµLªk²Õ¦¨¥»©Òºô¸ô©Ò»Ýªº³Æ´©ªººô¸ô¬[ºc¡C©ó¬O±Ò°ÊOSPF³q«H¨ó©w¡A¨Ï±o¥»©Ò¨âºô¸ô¥D·F½u¶¡«Ê¥]¸ô®|ªº¿ï¾Ü¡A³z¹LOSPF¿ï¾Ü¦¨¥»³Ì§Cªº¸ô®|¡C·íºô¸ô¬[ºc¨ã³ÆÀH®É¨Ìºô¸ôªº¨Ï¥Îª¬ºApºâ³Ì¨Î¤§¶Ç°e¸ô®|¯à¤O®É¡A¾D¹Jºô¸ô½u¸ô¤¤Â_®É¡AOSPF·|«·spºâ¡A§ä¥X¥t¤@±ø³Ì¨Î¥i¨ì¹F¤§¸ô®|¡A¹F¨ìºô¸ô³Æ´©ªº®ÄªG¡C
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¥»©Ò©Ò°Ïºô¸ô«Ø¸m°_¨B¸û¨ä¥L³æ¦ì±ß¡A¦ý«o¦]¦¹¦Ó±o¨ì¾Ç²ß©M±Ä¥Î³Ì·sºô¸ô§Þ³Nªº¾÷·|¡A¥»©Ò¤w¨ã¦³²Ä¤T¼hºô¸ô¥æ´«(Layer 3 switching)ªº³Ì·sºô¸ô§Þ³N¡A±N¥iº¡¨¬²{¶¥¬q¹ïºô¸ôªº»Ý¨D¡C¦ýºô¸ô§Þ³N¤£Â_±À³¯¥X·s¡A¬°º¡¨¬¥»©Ò¨Ï¥ÎªÌªº»Ý¨D¤Î°t¦X¸ê°T¬ì§Þªº¯ß°Ê¡AÀH®É¹ï·s¤@¥Nºô¸ôªº·s°ÊºAªº´x´¤¬O¥²nªº¡A¤]¬O¥»©ÒÄ~Äò§V¤Oªº¤è¦V¡C
¥»©Ò©^«ü¥Ü¥[¤J°ê¤º¤U¤@¥Nºô»Úºô¸ô(NGI¡ANext Generation Internet)À³¥Îpµeªº¶}µo¡A°Ñ¥[¦¹pµe¥i¨Ï¥»©Ò¹ï·s¤@¥Nºô»Úºô¸ôªº§Þ³N¤W§ó¯à¤F¸Ñ¡Aµ²¦X¥»©Ò¬J¦³ºô¸ô¸ê·½¡A°µ³Ì¦³®ÄªºÀ³¥Î¡A¥H´£¤É¥»©Ò¬ãµo¦¨®Ä¡CºîÆ[¤Wz¡Aºô¸ôÀ³¥Î»Ý¨Dªº¤£Â_ÂX¼W¡A«P¨Ïºô¸ô¬ì§Þªº§ó·s¡A¤]¼W¥[¤Fºô¸ô³W¹º³]pªº§xÃø«×¡A³W¹º³]pªÌ°£¶·¤F¸Ñ¥»©Òºô¸ô²{¦³ª¬ªp©M»Ý¨D¥~¡A§óÀ³¯à´x´¤¸ê°T©Mºô¸ô¬ì§Þªº³Ì·s°ÊºA¡C¬°°t¦X¤é«áªºª@¯Å¡A¥»©Ò±N¤Àºô¸ô·s§Þ³N¡Bºô¸ôºÞ²z©Mºô¸ô¦w¥þ¤T¤è±¶i¦æ¡F¦bºô¸ô·s§Þ³N¤W¡Agigabit router¡BNGI¤ÎIPV6¬O¥Dn«ÂI¡C¦bºô¸ôºÞ²z¤W¡A±NµÛ«©óSNMP¡BRMON2ºô¸ôºÞ²z¸ê®Æ®wªº²Îp¤ÀªRÀ³¥Î»P·s¤@¥NÀ³¥Î¨t²Î¾É¦Vªººô¸ôºÞ²z¤u¨ãªºÀ³¥Î¡Fºô¸ô¦w¥þ¤è±«h¶·°¼«±j¤Æ¥»©Ò©Ò¤º¨¾¤õÀð¨t²Î»P¥D¦øªA¾÷ªº¨t²ÎºÞ²z¡B¨¾¬r³nÅ骺§ó·s»Pºô¸ô¹wĵ¨t²Îªº«Ø¥ßµ¥¤u§@¡C
6. °Ñ¦Ò¤åÄm
[1]Black, Uyless D.,
"ATM :Foundation for Broadband Networks", Prentice-Hall, 1995[2] ATM forum Technical Committee, "Multi-Protocol Over ATM Version 1.0", AF-MPOA-0087.000, July 1997
[3] Peter Newman, Greg Minshall, and Tom Lyon, "IP Switching : ATM Under IP", Ipsilon Networks Inc., http://www.iprg.nokia.com/about/technology/paper/newman0001.htm
[4]. Y. Rekhter, B. Davie, D. Katz, E. Rosen, G. Swallow, "Cisco Systems' Tag Switching Architecture Overview", RFC 2105, Cisco Systems, Inc., February 1997
[5].Gigabit Ethernet Alliance, " White Paper :Gigabit Ethernet ", June 1998, http://www.gigabit-ethernet.org/technology/whitepapers/gige_0698/papers98_toc.html
[6]. ATM forum Technical Committee, "PNNI Version 1.0", AF-PNNI-0055.000, Mar 1996
[7]. ³¯´º³¹, "The PNNI architecture", °ê¥ß¤¤¥¿¤j¾Ç, Oct 1996
[8]. ATM forum Technical Committee, "LAN Emulation over ATM 1.0", AF-LANE-0021.000, Jan 1995
[9]. "White Paper: Auto Tracker Virtual LAN Architecture", xylan Corp., http://www.xylan.com/whitepaper/autotrk/main.html
[10]. J. Moy, "OSPF version 2", RFC 2178, Cascade Communications Corp., July 1997
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