ethernet\u7684\u985e\u578b\u8207802.3\u4ee3\u865f
802.3\/a\/i :ethernet
802.3u:fast ethernet
802.3z:\u5728\u5149\u7e96\u4e0a\u7684gigabit ethernet
802.3ab:\u5728utp\u4e0a\u7684gigabit ethernet
802.3ae:10gigabit ethernet
ps:
10m,100m,1000m
\u5728layer2\u90fd\u662f\u76f8\u540c\u7684,\u6240\u4ee5\u7db2\u8def\u53ef\u4ee5\u4e92\u901a
\u4f46\u5728layer1\u662f\u4e0d\u540c\u7684,\u6240\u4ee5\u901f\u5ea6\u6703\u53d7\u5230\u9650\u5236<\/p>\n\n\n\n
…………………………………<\/p>\n\n\n\n
ethernet(\u4e59\u592a\u7db2\u8def) IEEE\u5b9a\u7fa9\u4e59\u592a\u7db2\u63a5\u7dda(\u8ddd\u96e2*5\u70ba\u7db2\u8def\u6700\u5927\u9577\u5ea6) \u5982\u4e0b: PS ……………………………………… \u4fdd\u7559\u6240\u6709\u820a\u683c\u5f0f\u4ecb\u9762\u7a0b\u5e8f\u898f\u5247 1000base-x<\/strong>:IEEE802.3z-1998 1000base-T<\/strong>:IEEE802.3ab-1999 \u5176\u4ed6\u88dc\u5145 10gbe\/10gigabit<\/strong><\/p>\n\n\n\n 802.3ae,2002 10GBASE-CX4<\/strong> ethernet\u7684\u985e\u578b\u8207802.3\u4ee3\u865f802.3\/a\/i&n …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[26],"tags":[],"class_list":["post-801","post","type-post","status-publish","format-standard","hentry","category-osi-layer2"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/801","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/comments?post=801"}],"version-history":[{"count":0,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/801\/revisions"}],"wp:attachment":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/media?parent=801"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/categories?post=801"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/tags?post=801"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/strong>line encoding(\u7dda\u6027\u7de8\u78bc)\u578b\u614b\u70bamanchester(\u66fc\u5fb9\u65af\u7279)
csma\/cd\u7684\u5b58\u53d6\u6a5f\u5236,\u6700\u5927\u9577\u5ea62500\u516c\u5c3a
10mbps\u5728mac\u5b50\u5c641bit\u9700100ns(\u5948\u79d2)
slot time(\u8a0a\u69fd\/\u8a0a\u6846\u6642\u9593)\u70ba512bit-times(64byte),\u6642\u9593\u9593\u9694\u70ba51.2\u5fae\u79d2
interframe spacing(\u8a0a\u6846\u9700\u9593\u9694)96bit,\u6240\u9700\u6642\u9593\u70ba9.6\u5fae\u79d2(96bit*100ns)
\u8a0a\u6846\u9577\u5ea6\u6700\u5c0f64byte,\u6700\u59271518byte
collision jam size(\u78b0\u649e\u64c1\u585e\u5927\u5c0f)\u70ba32bit<\/p>\n\n\n\n
10base5(thick ethernet)<\/strong>
\u3000\u4f7f\u7528RG11\u7c97\u540c\u8ef8 500\u5c3a \u652f\u63f4100\u7bc0\u9ede \u53ea\u6709\u534a\u96d9\u5de5 BUS\u62d3\u6a38 \u4e5f\u7a31\u70ba802.3
\u3000\u6700\u65e9\u768410m\u4e59\u592a\u7db2\u8def,\u7e9c\u7dda\u9ad4\u7a4d\u5927\u91cd\u91cf\u91cd\u5177\u96e3\u5b89\u88dd,\u4f46\u8ddd\u96e2\u9577
10base2(thin ethernet)<\/strong>
\u3000\u4f7f\u7528RG58\u7d30\u540c\u8ef8 185\u5c3a \u652f\u63f430\u7bc0\u9ede \u53ea\u6709\u534a\u96d9\u5de5 BUS\u62d3\u6a38 \u4e5f\u7a31\u70ba802.3a
\u30001985\u5e74\u554f\u4e16,\u5f88\u9577\u6642\u9593\u70ba10m\u4e59\u592a\u7db2\u8def\u4e3b\u6d41,\u53ef\u8655\u7406\u7d42\u7aef\u96fb\u963b\u7684\u554f\u984c,\u5bb9\u6613\u5b89\u88dd\u6210\u672c\u66f4\u4f4e
10baseT(twisted-pair ethernet)<\/strong>
\u3000\u4f7f\u7528UTPcat3,4,5 100\u5c3a \u652f\u63f41024\u7bc0\u9ede \u5168\u96d9\u5de5\u534a\u96d9\u5de5 STAR\u62d3\u6a38 \u4e5f\u7a31\u70ba802.3i
\u30001990\u5e74\u554f\u4e16,\u7531\u65bc\u8ddd\u96e2\u53ea\u6709100\u516c\u5c3a,\u4fc3\u4f7frepeater\u53cahub\u76f8\u7e7c\u554f\u5e02,\u4e26\u5ef6\u9577\u8ddd\u96e2\u5230500\u516c\u5c3a,\u4e5f\u7522\u751f\u4e86543\u6cd5\u5247
\u3000\u9700\u6c42\u589e\u52a0\u4f7f\u983b\u5bec\u51fa\u73fe\u9650\u5236,\u5f8c\u4f86switch\u8207\u5de5\u4f5c\u7ad9\u9ede\u5c0d\u9ede\u7684\u9023\u7dda\u89e3\u6c7a\u4e86\u983b\u5bec\u554f\u984c
10baseF
<\/strong>\u3000FIBER 2000\u5c3a 1024\u7bc0\u9ede
1base5(starLAN)<\/strong>
\u3000UTP 500\u5c3a
10broad36
<\/strong>\u300075\u6b50\u59c6\u540c\u8ef8 1800\u5c3a*2 \u9069\u5408CATV<\/p>\n\n\n\n
base\u4ee3\u8868\u6578\u4f4d\u7684Baseband(\u57fa\u983b\u8a0a\u865f)\u540c\u4e00\u6642\u9593\u5c31\u53ea\u6709\u4e00\u7d44\u8a0a\u865f\u5728\u50b3\u8f38
broad\u4ee3\u8868\u985e\u6bd4\u7684Broadband\u5c04\u983b\u8a0a\u865f\u4ee5\u4e0d\u540c\u7684\u8f09\u6ce2\uff0c\u50b3\u8f38\u4e0d\u540c\u7684\u8a0a\u865f(PSK\u7de8\u78bc)<\/p>\n\n\n\n
Fast Ethernet(\u5feb\u901f\u4e59\u592a\u7db2\u8def)<\/strong>
\u6700\u5927\u9577\u5ea6250\u516c\u5c3a\uff1a\u8ddd\u96e2\u77ed10\u500d
\u8a0a\u6846\u5927\u5c0f64-1518byte
100mbps\u5728mac\u5b50\u5c641bit\u970010ns(\u5948\u79d2)
slot time(\u8a0a\u69fd\u6642\u9593)\u70ba512bit(64byte),\u6642\u9593\u9593\u9694\u70ba5.12\u5fae\u79d2
\u8a0a\u6846\u9700\u9593\u969496bit,\u6240\u9700\u6642\u9593\u70ba0.96\u5fae\u79d2(96bit*10ns)
\u6539\u70ba\u4f4d\u5143\u7de8\u78bc\u6cd5(bit encoding) ex:8b6t,4b5b
\u7de8\u78bc\u7684\u7b2c\u4e00\u500b\u90e8\u4efd\u4f7f\u75284b\/5b(4\u4f4d\u5143\/5\u4f4d\u5143),\u7b2c\u4e8c\u90e8\u4efd\u4f7f\u7528line encoding(\u7dda\u6027\u7de8\u78bc)
\u9700synchronization(\u540c\u6b65\u5316),\u7121\u8cc7\u6599\u50b3\u905e\u6642\u4e5f\u8981\u5fc5\u9808\u586b\u6eff\u7a7a\u767d\u7684\u6642\u9593\u4e26\u7dad\u6301\u540c\u6b65
collision jam size(\u78b0\u649e\u64c1\u585e\u5927\u5c0f)\u70ba32bit<\/p>\n\n\n\n
\u9808\u5728 MAC \u6b21\u5c64\u8207 PMD \u6b21\u5c64\u9593\u52a0\u4e0a\u4e00\u500b CS \u6b21\u5c64(\u8868\u7db2\u5361\u9808\u63db)
\u652f\u63f4Auto-negotiation
\u5feb\u901f\u4e59\u592a\u7db2\u8def\u63a5\u7e9c\u65b9\u5f0f,(\u661f\u72c0)
100baseT,t\u4ee3\u8868\u96d9\u7d5e\u7dda,\u5206\u70ba100baseT2,100baseT4,100baseTX
100BaseX:\u4e5f\u7a31\u70ba802.3u\u5206\u70baTX\u8207FX
100baseT<\/strong>4<\/strong>:
\u30004pair,cat3,4,5utp,\u96fb\u8a71\u7dda\u7cfb\u7d71\u4f7f\u7528
\u3000\u3000\u7b2c134\u5c0d\u7528\u4f86\u50b3\u8a0a\u6846,\u7b2c2\u5c0d\u7528\u4f86\u5075\u6e2c\u78b0\u649e
\u3000\u3000\u7b2c234\u5c0d\u7528\u4f86\u63a5\u8a0a\u6846,\u7b2c1\u5c0d\u7528\u4f86\u5075\u6e2c\u78b0\u649e
\u3000\u6700\u9577\u652f\u63f4100\u516c\u5c3a,\u8a0a\u865f\u901f\u5ea625mhz,\u534a\u96d9\u5de5
\u3000\u75288B6T\u7de8\u78bc\u6cd5,
\u3000NEXT(Next-end Crosstalk, \u8fd1\u7aef\u4e32\u97f3):\u8f03\u5f37\u7684\u8a0a\u865f\u53ef\u80fd\u8aa4\u5224\u6210\u4e32\u97f3
\u3000\u885d\u649e\u6642\u6703\u9001\u51fa\u64fe\u4e82\u8a0a\u865f (jam sequence) \u505c\u6b62\u50b3\u9001\u8a0a\u6846
100base-T2<\/strong>:
\u30002paiir,cat3,4,5UTP\u7dda,\u9700\u6578\u4f4d\u4fe1\u865f\u8655\u7406\u5668\u8655\u7406\u7de8\u78bc\u6a5f\u5236,
\u3000\u6700\u9577\u652f\u63f4100\u516c\u5c3a,\u5168\u96d9\u5de5\u534a\u96d9\u5de5
100base-TX<\/strong>:
\u30002pair,cat5UTP,or 2*150\u6b50\u59c6STP,\u9023\u63a5\u5668\u53efRJ-45\u6216shielded(\u906e\u853d\u5f0fDB-9)\u63a5\u982d
\u3000\u6700\u9577\u652f\u63f4100\u516c\u5c3a,\u8a0a\u865f\u901f\u5ea6125mhz,\u5168\u96d9\u5de5\u534a\u96d9\u5de5
\u3000\u75284b\/5b\u7de8\u78bc\u6cd5,\u5728scrambled(\u96dc\u4e82\u62fc\u6e4a)\u4e26\u8f49\u63db\u6210MTL3(multilevel transmission3,\u591a\u5c64\u6b21\u4e4b\u50b3\u8f38\u4e09\u5c64)
100base-FX<\/strong>\uff1a
\u3000\u5169\u689d\u591a\u6a21FIBER,\u591a\u6a21\u534a\u96d9\u5de5400\u5c3a\u5168\u96d9\u5de52\u516c\u91cc,\u6216\u55ae\u6a2120~100\u516c\u91cc
\u3000\u6bcf\u689d\u7dda\u7528\u65bc\u4e0d\u540c\u65b9\u5411,\u4e0d\u53ef\u7528hub,\u9023\u63a5\u5668\u70baMIC(\u96d9\u5de5\u5a92\u9ad4\u4ecb\u9762\u9023\u63a5\u5668)\u6216ST\u6216SC
\u3000\u75284b\/5b\u7de8\u78bc\u6cd5,\u3000
100base-SX<\/strong>:
\u3000FIBER,275\/550\u5c3a<\/p>\n\n\n\n
…………………………………………………………………………………………..
Gigabit Ethernet (<\/strong>1995)<\/strong>
\u4fdd\u7559\u6240\u6709\u820a\u683c\u5f0f\u4ecb\u9762\u7a0b\u5e8f\u898f\u5247
\u8f09\u6ce2\u5ef6\u4f38Carrier Extension\u6280\u8853,\u8a0a\u6846\u7206\u767c(Frame Bursting)\u6280\u8853
burst limit(\u7a81\u767c\u91cf\u9650\u5236):65536\u4f4d\u5143
\u63a1\u661f\u72c0\u67b6\u69cb\u5bb9\u932f\u6027\u9ad8
\u7686\u63a1\u9ede\u5c0d\u9ede\u914d\u7f6e(star,\u7528switch,hub\u7b49),\u800c\u975e\u4e4b\u524d\u7684\u591a\u9ede\u914d\u7f6e(bus)
\u8a0a\u6846\u5927\u5c0f64-1518byte(\u6216\u8a0a\u6846\u5927\u5c0f512-1518byte)
1000mbps\u5728mac\u5b50\u5c641bit\u97001ns(\u5948\u79d2)
slot time(\u8a0a\u69fd\u6642\u9593)\u70ba4096bit(512byte),\u6642\u9593\u9593\u9694\u70ba4.096\u5fae\u79d2
\u5ef6\u4f38\u8f09\u6ce2\u9577\u5ea6448byte
\u8a0a\u6846\u9700\u9593\u969496bit,\u6240\u9700\u6642\u9593\u70ba0.096\u5fae\u79d2(96bit*1ns)
collision jam size(\u78b0\u649e\u64c1\u585e\u5927\u5c0f)\u70ba32bit
\u8a0a\u865f\u7cfb\u7d71\u5c6c\u5168\u96d9\u5de5<\/p>\n\n\n\n
1996\u516d\u6708 IEEE 802.3z\u4efb\u52d9\u5c0f\u7d44 (task force)\u6210\u7acb
1997\u4e00\u6708 \u958b\u59cb\u5be9\u67e5\u7b2c\u4e00\u7248\u7684\u8349\u6848(Draft D1)
1998\u4e8c\u6708 \u5be9\u67e5\u7b2c4.1\u7248\u7684\u8349\u6848(Draft D4.1),\u6210\u7acbGigabit Ethernet\u6a19\u6e96
\u4f7f\u7528fiber,\u4f7f\u75288b10b(8bit\/10bit)\u7de8\u78bc\u8f49\u63db\u6210NRZ(\u4e0d\u518d\u56de\u5230\u96f6\u6e96\u4f4d)\u7dda\u6027\u7de8\u78bc
1000base-SX:fiber,62.5\u5fae\u7c73MMF275m,50\u5fae\u7c73MMF550m,\u8a0a\u865f\u662f\u77ed\u6ce2\u96f7\u5c04\u6216LED,\u6ce2\u9577850nm,s\u4ee3\u8868short
1000base-LX\/LH:fiber,9\u5fae\u7c73SMF10km,62.5\u820750\u5fae\u7c73MMF550m,\u8a0a\u865f\u662f\u9577\u6ce2\u96f7\u5c04,\u6ce2\u95771310nm,l\u4ee3\u8868long
1000base-CX:2pair stp,25m
1000BASE-ZX:fiber,9\u5fae\u7c73SMF70km,8\u5fae\u7c73SMF100km,\u8a0a\u865f\u662f\u96fb\u5c04,\u6ce2\u95771550
ps:
STP(Shielded twisted pair)
MMF(Multimode fiber)\u591a\u6a21\u5149\u7e96
SMF(singlemode fiber)\u55ae\u6a21\u5149\u7e96<\/p>\n\n\n\n
4pair,cat5eutp,\u4f7f\u7528\u5168\u90e8\u76848\u689d,\u6bcf\u689d\u63d0\u4f9b250mbps\u7684\u50b3\u8f38\u91cf
\u30001347\u8ca0\u8cac\u50b3\u905e,2568\u8ca0\u8cac\u63a5\u6536
\u6700\u9577\u652f\u63f4100\u5c3a
\u7de8\u78bc\u7b2c\u4e00\u90e8\u4efd\u4f7f\u75288b1q4(8bit-1quinary quarter,4\u7d445\u9805\u4f4d\u5143\u7d44)
\u7b2c\u4e8c\u90e8\u4efd\u4f7f\u75284d-pam5(4dimensional 5level pulse amplitude modulation,4\u7dad5\u7d1a\u8108\u885d\u8abf\u5e45\u6280\u8853)<\/p>\n\n\n\n
1
\u5168\u96d9\u5de5\u9ede\u5c0d\u9ede\u93c8\u8def\uff08Full-duplex point-to-point links\uff09:Gigabit EtherSwitch\u4ea4\u63db\u6a5f,\u5168\u96d9\u5de5,\u7121\u78b0\u649e
\u534a\u96d9\u5de5\u5171\u4eab\u885d\u649e\u7279\u6027\u7684\u7db2\u57df (Half-duplex shared collision domain):Ethernet Hub\u96c6\u7dda\u5668\u93c8\u8def,\u55aerepeater\u4e0b\u5141\u8a31\u76f4\u5f91200\u5c3a\u6210\u529f\u50b3\u9001
\u8a0a\u69fd\u6642\u9593(slot time):\u7db2\u8def\u4e2d\u6700\u9577\u7684\u4f86\u56de\u50b3\u905e\u5ef6\u9072\u6642\u9593\u6240\u63a8\u7b97\u800c\u4f86
\u8a0a\u7206\u6700\u5927\u9577\u5ea6\uff08\u8a0a\u7206\u4e0a\u9650\uff09:12,000\u4f4d\u5143\u6642\u9593,1997\u8b8a\u70ba65,536\u4f4d\u5143\u6642\u9593
2
\u534a\u96d9\u5de5\u4e0b\u89e3\u6c7a25\u516c\u5c3a\u554f\u984c\uff08\u589e\u52a0\u534a\u5f91\uff09
\u8f09\u6ce2\u5ef6\u4f38:\u589e\u52a0\u8a0a\u69fd\u6642\u9593\u514b\u670d\u6700\u77ed\u8a0a\u6846\u8207\u6642\u69fd\u6642\u9593\u7684\u5dee\u7570\u554f\u984c
\u6700\u77ed\u8a0a\u6846\u4fdd\u630164byte,\u6bcf\u6210\u529f\u50b3\u4e00\u6b21\u589e\u52a064byte
\u8f09\u6ce2\u5ef6\u4f38\u7b26\u865f\u4f4d\u7f6e\u5728\u8a0a\u6846\u6aa2\u67e5\u78bc(FCS)\u4e4b\u5f8c
\u50b3\u9001\u6642\u9047\u5230\u78b0\u649e\u5247\u9001\u51fa\u64fe\u4e82\u8a0a\u865f(jam signal 32bit)\u4f86\u505c\u6b62
\u8a0a\u6846\u7206\u767c\uff1a\u5728\u4e00\u500b\u8a0a\u7206(burst)\u4e2d\u50b3\u9001\u8a31\u591a\u7b46\u8a0a\u6846,\u4e4b\u9593\u4ee5\u5ef6\u4f38\u8f09\u6ce2\u5206\u96e2
\u6bcf\u500b\u8a0a\u7206\u7684\u7b2c\u4e00\u7b46\u8a0a\u6846\u50b3\u9001\u6642\u9593\u9808\u81f3\u5c11\u7b49\u65bc\u4e00\u500b\u6642\u69fd\u6642\u9593,\u8a0a\u6846\u904e\u77ed\u4ee5\u5ef6\u4f38\u8f09\u6ce2\u52a0\u9577\u81f3512byte
1\u50b3\u9001\u524d\u8a2d\u5b9a\u65d7\u6a19\u8868\u6b64\u8a0a\u6846\u662f\u8a0a\u7206\u7b2c\u4e00\u7b46\u8a0a\u6846\uff0c\u4e26\u555f\u52d5\u8a0a\u7206\u8a08\u6642\u5668
2\u82e5\u8a72\u8a0a\u6846\u9577\u5ea6\u4e0d\u53ca\u6642\u69fd\u6642\u9593,\u5247\u50b3\u9001\u5ef6\u4f38\u8f09\u6ce2\u586b\u6eff
3\u6210\u529f\u50b3\u9001\u4e14\u672a\u903e\u6642\u5247\u50b3\u900196bit\u5ef6\u4f38\u8f09\u6ce2
4\u82e5\u6709\u8a0a\u6846\u5373\u53ef\u50b3,\u7121\u5247\u7d50\u675f\u8a0a\u7206
…………………………………………………………………………………………..<\/p>\n\n\n\n
\u53ea\u652f\u63f4\u5168\u96d9\u5de5,\u4e0d\u9700csma\/cd
\u652f\u63f410m\/100m\/1000m\u7684\u4e59\u592a\u7db2\u8def
10gbps\u5728mac\u5b50\u5c641bit\u97000.1ns(\u5948\u79d2)
\u8a0a\u6846\u5927\u5c0f512-1518byte
\u8a0a\u6846\u9700\u9593\u969496bit,\u6240\u9700\u6642\u9593\u70ba0.0096\u5fae\u79d2(96bit*0.1ns)
interframe spacistretch ratio(\u8a0a\u6846\u9593\u9593\u9694\u4f38\u5c55\u6bd4\u4f8b)\u70ba104bit
\u6700\u5927\u50b3\u8ddd\u96e240\u516c\u91cc
\u53ef\u8207sonet(\u540c\u6b65\u5149\u7e96\u7db2\u8def),sdh(\u540c\u6b65\u6578\u4f4d\u968e\u5c64)\u76f8\u5bb9
\u4f7f\u75288B\/10B\u7de8\u78bc
ps:
IEEE 802.3ae standard differ from their predecessors only at the PHY(physical layer)
The standard defines several different transceivers that can be used as PMD(Physical Media Dependent) interfaces <\/p>\n\n\n\n
InfiniBand,15m,4x\u9023\u63a5\u5668\u548cCX4\u96fb\u7e9c,\u77ed\u96e2\u77ed
10GBASE-LX4\/LW4<\/strong>
fiber,MMF50\u5fae\u7c73300m,MMF62.5\u5fae\u7c73300m,SMF9\u5fae\u7c7310km
\u4f7f\u7528WWDM(wide-wavelength division multiplexing)
10GBASE-SR\/SW
<\/strong>fiber,MMF50\u5fae\u7c7366m,MMF50\u5fae\u7c73(2GHZ)300m,MMF62.5\u5fae\u7c7333m
10GBASE-LR\/LW<\/strong>
fiber,SMF9\u5fae\u7c7310km
10GBASE-ER\/EW<\/strong>
fiber,SMF9\u5fae\u7c7340km
ps:
S=short, L=long, E=extra-long wavelength
R=LAN PHY, W=WAN PHY
ps:
10GBASE-SW,10GBASE-LW,10GBASE-EW
\u7528\u65bcWAN,\u8207SONET,SDH\u8a2d\u5099\u5408\u4f5c <\/p>\n","protected":false},"excerpt":{"rendered":"