\u9023\u7d50\u5c0e\u5411\u5f0f\u00a01970
\u7b2c\u4e00\u500b\u516c\u5171\u8cc7\u6599\u7db2\u8def,CCITT\u767c\u5c55\u6a19\u6e96\u898f\u683c,\u65e9\u671f\u6574\u5408\u7528
\u9023\u7dda\uff1a
1\u96fb\u8166\u548c\u9060\u7aef\u5efa\u7acb\u9023\u7dda\uff08\u64a5\u901a\u96fb\u8a71\uff09
2\u9023\u7dda\u88ab\u8ce6\u4e88\u4e00\u500b\u865f\u78bc\u4ee5\u7528\u65bc\u8cc7\u6599\u50b3\u8f38\u5c01\u5305\u4e2d\uff08\u540c\u6642\u6703\u6709\u591a\u9023\u7dda\uff09
\u8a0a\u6846\uff1aheader3byte(12bit\u96fb\u8a71\u865f\u78bc,\u5c01\u5305\u5e8f\u865f,\u56de\u61c9\u78bc..),data128byte
\u904b\u4f5c\u7d04\u5341\u5e74\u88abframe relay\u8a0a\u6846\u50b3\u9001\u5f0f\u7db2\u8def\u53d6\u4ee3
\u7528\u5927\u91cf\u6aa2\u67e5\u82b1\u6389\u592a\u591a\u983b\u5bec(\u56e0\u7576\u6642\u7dda\u8def\u4e0d\u7a69),\u56fa\u5b9a\u901f\u7387,\u6700\u9ad8\u901f\u738764k,\u7121\u58c5\u585e\u63a7\u5236\u00a0<\/p>\n\n\n\n
X.25\u898f\u7bc4\u4e09\u5c64\uff1a
\u7db2\u8def\u5c64:\u7528PLP(packet layer protocol,\u5c01\u5305\u5c64\u5354\u5b9a)
\u3000\u8ca0\u8cac\u672c\u7aefDTE\u8207\u53e6\u4e00\u7aefDTE\u9593\u9023\u7dda\u5efa\u7acb\u8207\u670d\u52d9\u5354\u5546,\u53ca\u6d41\u91cf,\u932f\u8aa4\u63a7\u5236
\u3000\u8ca0\u8cac\u5efa\u7acb\u5206\u5c01\u4ea4\u63db\u7db2\u8def\u7684\u865b\u64ec\u96fb\u8def(SVC),\u56e0\u5728\u7db2\u8def\u5c64\u5efa\u6240\u4ee5\u53ef\u4ee5\u591a\u689d\u865b\u64ec\u96fb\u8def
\u3000\u6bcf\u689dVC\u7686\u6709\u8b58\u5225\u78bc\u7a31\u70baLCN(logical channel number,\u908f\u8f2f\u983b\u9053\u865f\u78bc)\u5728\u8fd1\u7aef\u53ca\u9060\u7aef\u7684DTE\u548cDCE\u4e4b\u9593
\u3000\u652f\u63f4PVC\u56fa\u63a5\u5f0f\u865b\u64ec\u96fb\u8def(\u7531X.25\u7db2\u8def\u63d0\u4f9b\u8005\u5efa\u7acb)
\u8cc7\u6599\u9023\u7d50\u5c64:\u4f7f\u7528LAPB\u63d0\u4f9b\u8cc7\u6599\u93c8\u7d50\u63a7\u5236(hdlc\u7684\u5b50\u96c6\u5408)
\u3000\u5404\u7bc0\u9ede\u6709\u6d41\u91cf\u63a7\u5236\u548c\u932f\u8aa4\u63a7\u5236
\u3000\u8a0a\u6846\u548chdlc\u540c,\u56e0\u901a\u8a0a\u70ba\u9ede\u5c0d\u9ede\u6240\u4ee5address\u6b04\u4f4d00000001\u662f\u7d66dte\u767c\u9001\u6307\u4ee4\u8207\u56de\u61c9\u7528,00000011\u662f\u7d66DCE\u767c\u9001\u6307\u4ee4\u8207\u56de\u61c9\u7528
\u3000\u8a0a\u6846\u985e\u578b\u6709\uff1aI-frame(\u5c01\u88ddPLP\u7528),S-frame(\u6d41\u91cf,\u932f\u8aa4\u63a7\u5236\u7528),U-frame(\u5efa\u7acb\u548c\u5207\u65b7DTE,DCE\u9023\u7dda)
\u3000U-frame\u5e38\u7528SABM,SABME,UA,DISC
\u3000DTE,DCE\u901a\u8a0a\u4e09\u968e\u6bb5
\u3000\u3000\u93c8\u7d50\u8a2d\u5b9a\uff1aDTE\u6216DCE\u9001\u51faSABM,\u5c0d\u65b9\u56de\u61c9UA\u5247\u5b8c\u6210
\u3000\u3000\u50b3\u9001\u8cc7\u6599\uff1a\u53ef\u7528I-frame\u6216U-frame\u6536\u9001\u7db2\u8def\u5c64\u5c01\u5305
\u3000\u3000\u93c8\u7d50\u5207\u65b7\uff1a\u67d0\u4e00\u65b9\u9001\u51faDISC,\u5c0d\u65b9\u56de\u61c9UA\u5247\u65b7\u7dda
\u5be6\u9ad4\u5c64:\u898f\u7bc4X.21\u6216X.21bis\u5354\u5b9a
ps:\u82e5\u60f3\u4f7f\u7528tcp\/ip\u5247\u7db2\u8def\u5c64\u6703\u91cd\u8986<\/p>\n\n\n\n
……………………………………………………..<\/p>\n\n\n\n
X.25v2,\u9023\u7d50\u5c0e\u5411\u5f0f,\u9023\u7d50\u7531vc(victual circuits)\u6240\u7d44\u6210
1980,\u7531ansi\u548citu-t\u5236\u5b9a
1991\u5e74\u4e00\u6708\u6210\u7acbFRF(Frame Relay Forum,\u8a0a\u6846\u50b3\u9001\u8ad6\u58c7)\uff0c\u4ee5\u4fbf\u5c07\u8a0a\u6846\u50b3\u9001\u5404\u9805\u76f8\u95dc\u670d\u52d9\u4e88\u4ee5\u6a19\u6e96\u5316<\/p>\n\n\n\n
\u7279\u6027\uff1a
\u6709CIR\u4fdd\u8b49\u983b\u5bec
\u7121\u6d41\u91cf\u63a7\u5236,\u7531\u7b2c\u4e09\u5c64\u8ca0\u8cac
\u7121\u932f\u8aa4\u63a7\u5236,\u9047\u5230\u932f\u8aa4\u76f4\u63a5\u4e1f\u68c4,\u932f\u8aa4\u63a7\u5236\u7531\u7b2c\u4e09\u5c64\u8ca0\u8cac
\u7c21\u5316\u7684frame\u63a7\u5236\u4f7f\u5ef6\u9072\u964d\u4f4e,\u56e0\u4f9d\u5e8f\u50b3\u9001,\u7121\u9023\u7dda\u5efa\u7acb,\u7121\u6d41\u91cf\u63a7\u5236,\u7121\u932f\u8aa4\u63a7\u5236
\u6709\u58c5\u585e\u63a7\u5236,\u5229\u75283\u500b\u64c1\u585e\u4f4d\u5143de,fecn,becn\u8655\u7406
\u53ef\u9ede\u5c0d\u9ede\u53ca1\u9ede\u5c0d\u591a\u9ede(\u4e3b\u516c\u53f8\u5c0d\u591a\u5206\u516c\u53f8)
\u7d71\u8a08\u591a\u5de5\u7684\u4ea4\u63db\u6280\u8853,\u4e5f\u7a31Fast Packet(\u5feb\u901f\u5206\u5c01)\u4ea4\u63db\u6280\u8853,\u63d0\u4f9b\u7684\u8a0a\u52d9\u91cf\u4ecb\u65bcLAN\u8207WAN\u4e4b\u9593
\u652f\u63f4PVC,SVC(\u9700\u85c9\u7531\u7db2\u8def\u5c64\u5354\u5b9aIP\u6216ISDN\u5e6b\u5fd9),SPVC
\u3000PVC\u7684\u52d5\u4f5c\u67092\u7a2e,\u50b3\u9001\u8cc7\u6599,\u6216IDLE(\u7a7a\u9592)
\u3000SVC\u7684\u52d5\u4f5c\u67094\u7a2e,\u4f86\u6e90\u7aef\u8ddf\u76ee\u7684\u7aef\u8981\u5efa\u7acb\u7dda\u8def,\u7136\u5f8c\u50b3\u9001\u8cc7\u6599,\u9001\u5b8c\u5c31\u6703IDLE,\u5982\u679cTIMEOUT\u5c31\u7d50\u675f\u9023\u7d50
\u975e\u56fa\u5b9a\u901f\u7387,\u901f\u7387\u50b3\u8f38\u70ba64Kbps(DS0)\u52301.544Mbps(T1)\u4ecb\u65bcISDN\u8207ATM\u4e4b\u9593,\u53ca44.376mbps,…\u7b49
\u6839\u64da\u9810\u8a2d\u88ab\u5206\u985e\u70baNBMA\u7db2\u8def<\/p>\n\n\n\n
\u512a\u9ede\uff1a
\u50b3\u9001\u985e\u4f3c\u5927\u7bc4\u570d\u7684\u5340\u7db2,\u53ef\u5728\u591a\u8fa6\u516c\u5ba4\u9593\u4e92\u9023,\u4e14\u4fbf\u5b9c
\u6bd4\u8f03\u5bb9\u6613\u5b78\u7fd2,\u540c\u6642\u4e5f\u6bd4\u8f03\u5bb9\u6613\u5be6\u4f5c
\u53ef\u548c\u6578\u64da\u901a\u4fe1\u5206\u516c\u53f8\u7684\u8d85\u9ad8\u901f\u6578\u64da\u4ea4\u63db\u7db2\u8def(ATM)\u4e92\u9023
\u9023\u63a5\u65b9\u5f0f\u7c21\u55ae,\u7db2\u8def\u6613\u65bc\u7dad\u8b77,\u901a\u4fe1\u5169\u7aef\u53ef\u63a1\u4e0d\u540c\u50b3\u8f38\u901f\u7387\uff0c\u964d\u4f4e\u901a\u4fe1\u6210\u672c
\u9069\u7528\u65bc1.544Mbps(T1)\u901f\u7387\u4ee5\u4e0b\uff0c\u50b3\u9001\u6578\u64da\u3001\u8a9e\u97f3\u7684\u7db2\u8def<\/p>\n\n\n\n
\u61c9\u7528\uff1a
1\u63d0\u4f9b\u5927\u578b\u8cc7\u8a0a\u7db2\u8def\u4e4b\u9ad8\u901f\u6578\u64da\u4ea4\u63dbbackbone(\u4e3b\u5e79)\u7db2\u8def\u3002
2\u63d0\u4f9b\u570b\u5167VAN(\u52a0\u503c\u578b\u7db2\u8def)\u696d\u8005\u4e4b\u4e3b\u5e79\u7db2\u8def\u3002
3\u63d0\u4f9bEthernet(\u4e59\u592a\u7db2\u8def)\u53caToken Ring(\u7b26\u8a18\u74b0)\u7b49\u7db2\u8def\u7684\u9023\u63a5\u7f3a\u9ede\uff1a
\u7121\u6cd5\u61c9\u4ed8\u66f4\u9ad8\u901f\u7684\u5354\u5b9a,\u5982B-ISDN
\u5927\u8a0a\u6846\u53ef\u80fd\u8b93\u5c0f\u8a0a\u6846\u7522\u751fdelay
\u4e0d\u9069\u5408\u50b3\u9001delay\u654f\u611f\u7684\u8cc7\u6599,\u5982\u5373\u6642\u8072\u97f3,\u8996\u8a0a
\u6c92\u6709\u8fa6\u6cd5\u63d0\u4f9b\u50cfATM\u90a3\u6a23\u7684\u5404\u7a2e\u9ad8\u968e\u670d\u52d9
nbma\u7684Routing Update\u7684Reachability Issue(\u53ef\u5230\u9054\u6027\u554f\u984c)
nbma\u7684Broadcast Replication(\u91cd\u8907\u767c\u9001\u5ee3\u64ad\u5c01\u5305)\u554f\u984c<\/p>\n\n\n\n
\u8a0a\u6846\u50b3\u9001\u898f\u7bc41.5\u5c64
\u8cc7\u6599\u93c8\u7d50\u5c64\u7684MAC\uff1a\u53ea\u4f54\u5176\u4e2d\u4e00\u90e8\u4efd,\u8a0a\u6846\u63a1LAPF(HDLC\u7c21\u5316\u7248)
\u3000\u5141\u8a31\u50b3\u9001\u7a81\u7206\u6027\u8cc7\u6599,\u8a0a\u6846\u50b3\u9001\u55ae\u4f4d\u5927\u5c0f\u4e0d\u56fa\u5b9a,\u53ef\u5bb9\u8a319\u5343\u500bbyte
\u3000\u6536\u5230\u932f\u8aa4\u7684\u8a0a\u6846\u6642\u5c07\u4e4b\u4e1f\u68c4(\u56e0\u932f\u8aa4\u63a7\u5236\u4ea4\u7d66\u7db2\u8def\u548c\u50b3\u8f38\u5354\u5b9a\u8ca0\u8cac)
\u3000FRAD(frame relay assembler\/disassembler,\u8a0a\u6846\u50b3\u9001\u7d44\u5408\/\u62c6\u89e3\u5668):\u7528\u4f86\u8655\u7406\u5176\u4ed6\u5354\u5b9a\u7684\u8a0a\u6846
\u3000VOFM(voice over frame relay\u8a0a\u6846\u50b3\u9001\u4e0a\u7684\u8a9e\u97f3\u50b3\u8f38):\u7528pcm\u58d3\u7e2e\u50b3\u5230\u7db2\u8def,\u7d93\u6fdf\u4f46\u7121\u597d\u54c1\u8cea
\u3000traffic control(\u8a0a\u52d9\u63a7\u5236):pvc\u53ea\u9700\u5354\u5b9a\u4e00\u6b21,svc\u6bcf\u6b21\u9023\u7dda\u9700\u5354\u5546
\u3000CIR(Committed Information Rate,\u7d04\u5b9a\u8cc7\u8a0a\u901f\u7387):\u4fdd\u8b49\u80fd\u5920\u4f7f\u7528\u7684\u50b3\u8f38\u901f\u7387,\u8d85\u904e\u5247\u4ee5best effort(\u76e1\u529b\u5f0f)\u50b3\u9001
\u3000access rate(\u5b58\u53d6\u901f\u7387):\u6700\u5927\u50b3\u8f38\u901f\u7387
\u3000committed burst size(\u7d04\u5b9a\u7a81\u7206\u91cf):\u8d85\u904eCIR,\u4e14\u53ef\u80fd\u5230\u9054access rate\u7684\u901f\u7387
\u3000excess burst(\u8d85\u6ea2\u7a81\u7206\u91cf)
\u5be6\u9ad4\u5c64:\u652f\u63f4\u4efb\u4f55ansi\u6a19\u6e96\u7684\u5354\u5b9a ex:u.35,x.21,eia\/tia232,eia\/tia449,eia\/tia530
\u3000\u65e9\u671f\u63a1\u7528T-Carrier,\u50b3\u8f38\u901f\u7387\u6700\u9ad8\u53ea\u6709T3\u6216E3,\u73fe\u5728\u6709SONET,\u53ef\u5728\u9ad8\u901f\u5149\u7e96\u7dda\u8def\u4e0a\u904b\u4f5c
ps:\u7db2\u8def\u5c64\u53ef\u652f\u63f4ip,ipx,apple talk,…\u7b49\u5354\u5b9a<\/p>\n\n\n\n
frame relay\u8a0a\u6846(\u50cfhdlc)\uff1aflag+address(\u53ef\u5ef6\u4f38)+\u5354\u5b9a+fcs+flag
address\u4f4d\u57402byte:DLCI(6bit)+C\/R+EA+DLCI(4bit)+FECN+BECN+DE+EA,(DLCI\u517110bit)
address\u4f4d\u57403byte:2byteaddress+DLCI(6bit)+0+EA,(DLCI\u517116bit)
address\u4f4d\u57404byte:2byteaddress+DLCI(7bit)+EA+DLCI(6bit)+0+EA,(DLCI\u517123bit)
C\/R\u6307\u4ee4\/\u56de\u61c9:\u63d0\u4f9b\u7d66\u4e0a\u5c64\u8b58\u5225\u8a0a\u6846\u662f\u6307\u4ee4\u6216\u56de\u61c9
EA\u5ef6\u4f38\u4f4d\u5740:\u70ba0\u8868\u9084\u6709\u4e00\u500b\u4f4d\u5143\u7d44\u5728\u5f8c\u9762,\u70ba1\u8868\u76ee\u524d\u4f4d\u5143\u7d44\u662f\u6700\u5f8c\u4e00\u500b
FECN(forward explicit congestion notification,\u5411\u524d\u58c5\u585e\u6307\u793a):\u8a2d\u70ba1\u6642,\u901a\u77e5\u76ee\u5730DTE\u5df2\u767c\u751f\u58c5\u585e
BECN(backward explicit congestion notification,\u5411\u5f8c\u58c5\u585e\u6307\u793a):\u8a2d\u70ba1\u6642,\u901a\u77e5\u5f8c\u9762\u8def\u7531\u5668\u5df2\u767c\u751f\u58c5\u585e
DE(Discard Eligibility,\u4e1f\u68c4\u8cc7\u683c):\u662f\u5426\u53ef\u907a\u68c4\u4f4d\u5143,\u70ba1\u8868\u58c5\u585e\u6642\u8a0a\u6846\u53ef\u4e1f\u68c4
ps:\u7576\u50b3\u9001\u7684\u5c01\u5305\u8d85\u904eCIR\u6642,\u4e14isp\u7db2\u8def\u58c5\u585e,\u5247\u8d85\u904e\u90e8\u5206\u7684frame relay\u8a0a\u6846\u6703\u6a19\u793ade\u4f4d\u5143<\/p>\n\n\n\n
DLCI(datalink connection identifion,\u8cc7\u6599\u93c8\u7d50\u9023\u7d50\u8b58\u5225\u78bc)
\u7528\u4f86\u8fa6\u5225\u4e0d\u540c\u7684vc,\u4e14\u53ea\u5c0d\u672c\u5730\u7aef\u7684\u9023\u7dda\u6709\u610f\u7fa9
\u5efa\u7acbvc\u5f8c,DTE\u6703\u5728DCE\u9593\u5f97\u5230\u4e00\u500bDLCI\u4ee5\u5b58\u53d6\u9060\u7aefDTE
DLCI\u4e5f\u53ef\u5728DCE\u9593\u5efa\u7acb
\u5169\u4e0d\u540c\u4ecb\u9762\u7684\u5169\u4e0d\u540c\u9023\u7dda\u53ef\u80fd\u6709\u76f8\u540cDLCI
\u8a0a\u6846\u50b3\u9001\u4ea4\u63db\u6a5f\u7684\u8def\u7531\u8868\u5c07\u9032\u4f86\u4ecb\u9762\u8207DLCI\u7d44\u5408\u5c0d\u61c9\u5230\u51fa\u53bb\u4ecb\u9762\u8207DLCI\u7d44\u5408
ps:\u81ea\u52d5\u5c0d\u61c9DLCI\u8207IP\u53ef\u4f7f\u7528IARP<\/p>\n\n\n\n
LMI(local management interface,\u5c40\u7aef\u7ba1\u7406\u754c\u9762)
\u63d0\u4f9bkeepalive,multicast,\u5141\u8a31dte\u6aa2\u67e5dce
\u8def\u7531\u5668\u8207\u9023\u7d50\u7684\u7b2c\u4e00\u500bframe relay\u4ea4\u63db\u6a5f\u4e4b\u9593\u6240\u7528\u7684\u4fe1\u865f\u6a19\u6e96
\u53ef\u50b3\u9001\u6709\u95dcisp\u8207dte\u4e4b\u9593vc\u7684\u904b\u4f5c\u8207\u72c0\u614b,\u5305\u62ec:
keepalive(\u4fdd\u6301\u5b58\u6d3b):\u78ba\u8a8d\u8cc7\u6599\u4ecd\u7136\u901a\u66a2
multicasting(\u591a\u9ede\u50b3\u64ad):LMI\u898f\u683c\u7684\u64f4\u5145\u9078\u9805,\u4f8b\u5982\u53ef\u7528\u4f86\u5206\u9001\u8def\u5f91\u8cc7\u8a0a\u8207ARP\u8acb\u6c42
global addressing(\u5168\u57df\u4f4d\u5740):\u63d0\u4f9b\u5168\u57df\u610f\u7fa9\u7d66dlci,\u8b93\u904b\u4f5c\u50cflan\u4e00\u6a23
vc state(\u865b\u64ec\u96fb\u8def\u72c0\u614b):\u63d0\u4f9bDLCI\u72c0\u614b,\u5305\u62ec:
\u3000active state(\u4f5c\u7528\u72c0\u614b):\u6bcf\u4ef6\u4e8b\u90fd\u5728\u904b\u4f5c,\u8def\u7531\u5668\u53ef\u4ea4\u63db\u8cc7\u8a0a
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\u8a0a\u606f\u683c\u5f0f\u6709ANSI T1.617 Annex D\u548cITU-T Q.933 Annex A,\u6216CISCO<\/p>\n","protected":false},"excerpt":{"rendered":"
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