OSI\/RM(Open System Interconnection reference model,\u958b\u653e\u5f0f\u901a\u4fe1\u7cfb\u7d71\u4e92\u806f\u53c3\u8003\u6a21\u578b)
1978\u5e74,\u7531ISO(\u570b\u969b\u6a19\u6e96\u5316\u7d44\u7e54)\u63d0\u51fa
\u8a66\u5716\u4f7f\u4e0d\u540c\u7684\u7db2\u8def\u80fd\u4e92\u76f8\u901a\u8a0a\u7684\u67b6\u69cb
\u6b64\u67b6\u69cb\u53c8\u7a31stack(\u5806\u758a)\u6216\u5354\u5b9a\u5806\u758a<\/p>\n\n\n\n
\u7279\u8272\u5982\u4e0b:
\u5404\u5c64\u4e0d\u77e5\u5225\u5c64\u5982\u4f55\u5de5\u4f5c,\u53ea\u77e5\u540c\u5c64\u7d1a\u5354\u5b9a
\u5c64\u8207\u5c64\u9593\u6709\u65e2\u5b9a\u5354\u8b70\u76f8\u4e92\u4ea4\u63db\u8655\u7406\u7d50\u679c
\u8d8a\u63a5\u8fd1\u61c9\u7528\u5c64\u8d8a\u8cb4\u8d8a\u6162\u8d8a\u4e0d\u53ef\u9760
\u7db2\u8def\u5143\u4ef6\u6a19\u6e96\u5316,\u4ee5\u4fbf\u5bb9\u8a31\u591a\u5ee0\u5546\u767c\u5c55\u548c\u652f\u63f4
ps:\u6b64\u70ba\u908f\u8f2f\u6027\u968e\u5c64,\u6709\u6642\u4e00\u5354\u5b9a\u5c0d\u61c9\u5230\u591a\u5c64,\u6216\u4e00\u5c64\u6709\u591a\u500b\u5354\u5b9a\u5728\u6e9d\u901a<\/p>\n\n\n\n
\u512a\u9ede\u5982\u4e0b:
\u53ef\u8b93\u61c9\u7528\u7a0b\u5f0f\u7684\u958b\u767c\u8005\u53ea\u9700\u4f9d\u7167\u5206\u5c64\u5f0f\u6a21\u5f0f\u898f\u683c\u7684\u5176\u4e2d\u4e00\u5c64\u4f86\u6539\u8b8a\u7a0b\u5f0f
\u5c07\u7db2\u8def\u901a\u8a0a\u6d41\u7a0b\u5207\u5272\u6210\u8f03\u7c21\u55ae\u7684\u5143\u4ef6,\u6709\u52a9\u65bc\u5143\u4ef6\u7684\u958b\u767c\u8a2d\u8a08\u8207\u6aa2\u4fee,
\u591a\u5bb6\u5ee0\u5546\u53ef\u958b\u767c\u6a19\u6e96\u5316\u7684\u7db2\u8def\u5143\u4ef6,\u7c4d\u7531\u5b9a\u7fa9\u5404\u5c64\u529f\u80fd\u4fc3\u9032\u6a19\u6e96\u5316
\u9632\u6b62\u53e6\u4e00\u5c64\u7684\u8b8a\u66f4\u5f71\u97ff\u5230\u5176\u4ed6\u5c64\u7d1a<\/p>\n\n\n\n
PDU(protocol data unit,\u5354\u5b9a\u8cc7\u6599\u55ae\u5143)<\/strong> ……………………………………..<\/p>\n\n\n\n \u4f7f\u7528\u8005\u7fa4\u7d44<\/p>\n\n\n\n Application Layer<\/strong>:\u8207\u61c9\u7528\u7a0b\u5f0f\u4ecb\u9762\u6e9d\u901a Presentation Layer<\/strong>:\u70ba\u4e0d\u540c\u5e73\u81fa\u7684\u61c9\u7528\u5c64\u63d0\u4f9b\u6578\u64da\u548c\u8a0a\u606f\u7684\u8a9e\u6cd5\u8868\u793a\u8b8a\u63db\u65b9\u6cd5 Session Layer<\/strong>:\u5b9a\u7fa9\u5982\u4f55\u9023\u63a5\u548c\u639b\u65b7\u9023\u63a5,\u5728\u7db2\u8def\u4e0a\u9762\u7684\u6578\u64da\u5982\u4f55\u4ea4\u63db Transport Layer<\/strong>:\u8a2d\u5b9a\u7bc0\u9ede\u9593\u8cc7\u6599\u50b3\u905e,\u932f\u8aa4\u6aa2\u6e2c\u548c\u4fee\u6b63\u7684\u65b9\u6cd5 ……………………………………..<\/p>\n\n\n\n \u7db2\u8def\u7fa4\u7d44<\/p>\n\n\n\n Network Layer<\/strong>:\u63d0\u4f9b\u8def\u7531\u548c\u5b9a\u5740\u7684\u529f\u80fd Data Link Layer<\/strong>:\u4fdd\u8b49\u7121\u932f\u7684\u7269\u7406\u4e0a\u7684\u6578\u64da\u50b3\u8f38 Physical Layer<\/strong>:\u78ba\u4fdd\u539f\u59cb\u7684\u6578\u64da\u53ef\u5728\u5404\u7a2e\u7269\u7406\u5a92\u9ad4\u4e0a\u9032\u884c\u50b3\u8f38 OSI\/RM(Open System Interconnec …<\/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":[30],"tags":[],"class_list":["post-748","post","type-post","status-publish","format-standard","hentry","category-networkconcept"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/748","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=748"}],"version-history":[{"count":0,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/748\/revisions"}],"wp:attachment":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/media?parent=748"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/categories?post=748"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/tags?post=748"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
OSI\/RM:<\/p>\n\n\n\n\u7b2c7\u5c64 application layer(\u61c9\u7528\u5c64)
\u7b2c6\u5c64 presentation layer(\u8868\u9054\u5c64)
\u7b2c5\u5c64 session layer(\u4ea4\u8ac7\u5c64)<\/td>\u61c9\u7528\u5c64<\/td><\/tr> \u7b2c4\u5c64 transport layer(\u50b3\u8f38\u5c64)
\u7b2c3\u5c64 network layer(\u7db2\u8def\u5c64)
\u7b2c2\u5c64 data link layer(\u8cc7\u6599\u9023\u7d50\u5c64)
\u7b2c1\u5c64 physical layer(\u5be6\u9ad4\u5c64)<\/td>\u8cc7\u6599\u6d41\u5c64<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\u76f8\u5c0d\u7684\u6bcf\u4e00\u5c64\u4ea4\u63db\u8cc7\u8a0a\u7684\u5354\u5b9a,\u5404\u5c64pdu\u5982\u4e0b
layer1\u70babit(\u4f4d\u5143),
layer2\u70baframe(\u8a0a\u6846),\u5728\u8cc7\u6599\u9023\u7d50\u5c64\u8dd1\u7684\u6700\u5c0f\u8cc7\u8a0a\u55ae\u4f4d
layer3\u70bapacket(\u5c01\u5305),\u5728\u7db2\u8def\u4e0a\u9762\u9032\u884c\u50b3\u8f38\u7684\u6700\u5c0f\u8cc7\u8a0a\u55ae\u4f4d
layer4\u70basegment(\u5340\u6bb5\/\u7247\u6bb5)\u6216Datagram(\u8cc7\u6599\u6bb5),\u5728\u50b3\u8f38\u5c64\u7684\u8cc7\u8a0a\u55ae\u4f4d,\u6703\u88ab\u5207\u6210\u5c01\u5305\u7d66\u7db2\u8def\u5c64
layer5~7\u70bamessage
ps:
layer4\u7684PDU\u4e5f\u7a31\u70baTPDU
ps:
fragment(\u788e\u7247):IP\u5305\u8d85\u51fa\u7db2\u7d61\u4e0a\u6700\u5927\u9650\u5236\u503c,\u5b83\u5c31\u6703\u5206\u6210\u82e5\u5e72\u5c0f\u5305 \u4f86\u6e90\u7aefosi mode\u7684\u5c64\u5fc5\u9808\u8207\u76ee\u5730\u7aef\u76f8\u5c0d\u61c9\u7684\u5c64\u6e9d\u901a,\u6b64\u5f62\u5f0f\u4e5f\u7a31peer-to-peer communication(\u5c0d\u7b49\u5f0f\u901a\u8a0a)
\u4e0a\u5c64\u7684pdu\u7d66\u4e0b\u5c64\u6642,\u4e0b\u5c64\u6703\u5c07\u4e0a\u5c64pdu\u9032\u884cencapsulation(\u5c01\u88dd)\u6210\u70ba\u4e0b\u5c64\u7684pdu,\u800cdecapsulation(\u89e3\u5c01\u88dd)\u5247\u76f8\u53cd
encapsulation\u9806\u5e8f\u70badata>segments>packet>frames>bits
decapsulation\u9806\u5e8f\u70babits>frames>packet>segments>data\u7528OSI\/RM\u6bd4\u7167PC1\u548cPC2\u5efa\u7acb\u9023\u7dda\u7684\u72c0\u6cc1<\/p>\n\n\n\napplication layer
presentation layer
session layer
transport layer
network layer
data link layer
physical layer
…………………
pc1<\/td>
<–><\/td>
network layer
data link layer
physical layer
……………..
router1<\/td>
<–> internet <–><\/td>
network layer
data link layer
physical layer
……………..
router2<\/td>
<–><\/td>application layer
presentation layer
session layer
transport layer
network layer
data link layer
physical layer
…………………
pc2<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\u529f\u80fd:\u5b9a\u7fa9\u61c9\u7528\u7a0b\u5f0f\u5982\u4f55\u9032\u5165OSI\u6a21\u5f0f\u9032\u884c\u50b3\u9001
\u8207\u6b64\u5c64\u76f8\u95dc\u7684\u6709:web,ftp,email,…\u7b49
ps:telnet\u53ef\u6e2c\u8a66\u5169\u4e3b\u6a5f\u5728\u61c9\u7528\u5c64\u7684\u9023\u7d50\u72c0\u6cc1<\/p>\n\n\n\n
\u5b9a\u7fa9\u4e86\u6578\u64da\u7684syntax(\u8a9e\u6cd5),\u8b8a\u66f4,\u683c\u5f0f,\u82e5\u8a9e\u6cd5\u548c\u683c\u5f0f\u4e0d\u540c\u6642,\u5c07\u5b9a\u7fa9\u5982\u4f55\u7ffb\u8b6f\u8207\u8f49\u63db
\u529f\u80fd\uff1a\u8ca0\u8cac\u5728\u4e0d\u540c\u6a5f\u5668\u4e4b\u9593,\u91dd\u5c0d\u7279\u5b9a\u4e3b\u6a5fCPU\u9032\u884c\u7de8\u78bc\u8f49\u63db
\u505a\u6cd5\uff1a\u7a0b\u5f0f\u7522\u751f\u8cc7\u6599\u50b3\u9001\u6642,\u6703\u63db\u6210\u7db2\u8def\u6a19\u6e96\u7de8\u78bc\u683c\u5f0f\u518d\u4ea4\u7531\u4e0b\u5c64\u8655\u7406,\u6216\u4ee5\u6709\u610f\u7fa9\u65b9\u5f0f\u986f\u793a\u7d66\u4e0a\u5c64,\u5982\u4e0b:
1\u5b57\u5143\u78bc\u8f49\u63db ex:ASCII\u8f49EBCDIC \u78bc
2\u8cc7\u6599\u5f62\u614b\u8f49\u63db ex:CR\u78bc,CR-LF \u78bc,\u6574\u6578,\u6d6e\u9ede\u6578\u9593\u8f49\u63db
ps:ndr(network data representations,\u7db2\u8def\u8cc7\u6599\u8868\u793a\u683c\u5f0f):asn.1,xdr
osi\u5efa\u8b70\u7528asn.1\u62bd\u8c61\u8a9e\u610f\u8868\u793a\u6cd5\u505a\u8f49\u8b6f
\u7de8\u8f49\u78bc\u4e5f\u53ef\u7528XDR(External Data Representation,\u5916\u90e8\u6578\u64da\u8868\u793a\u6cd5)
3\u8cc7\u6599\u58d3\u7e2e\u63d0\u9ad8\u901f\u5ea6,\u53ef\u5206\uff1a
\u3000losslessdata(\u7121\u640d\u58d3\u7e2e)\uff1aRLE\u9023\u7e8c\u9577\u5ea6\u7de8\u78bc,\u7d71\u8a08\u58d3\u7e2e(\u6469\u65af\u78bc,\u54c8\u592b\u66fc\u7de8\u78bc,LZW\u7de8\u78bc),\u76f8\u5c0d\u58d3\u7e2e
\u3000lossydata(\u6709\u640d\u58d3\u7e2e)\uff1ajpeg,mpeg
4\u52a0\u89e3\u5bc6\u589e\u52a0\u5b89\u5168\u6027
\u5176\u4ed6\u8207\u6b64\u5c64\u76f8\u95dc\u7684\u6709,pict,tiff,midi,quicktime,rtf<\/p>\n\n\n\n
\u529f\u80fd\uff1a\u5efa\u7acb\u548c\u7ba1\u7406\u96fb\u8166\u7a0b\u5f0f\u8207\u96fb\u8166\u7a0b\u5f0f\u9593\u7684\u6e9d\u901a\u6a21\u5f0f,\u6536\u9001\u670d\u52d9
\u505a\u6cd5\uff1a\u5b9a\u7fa9\u9023\u7dda\u8acb\u6c42,\u7d50\u675f,\u50b3\u9001,\u63a5\u6536\u72c0\u614b\u7684\u8a2d\u5b9a\u7b49\u52d5\u4f5c,\u5982\u4e0b
1\u5141\u8a31\u7a0b\u5f0f\u4ee5\u96fb\u8166\u540d\u7a31\u8a3b\u518a\u6210\u7db2\u8def\u4e0a\u552f\u4e00\u7684\u4f4d\u5740
2\u5728\u96fb\u8166\u9593\u5efa\u7acb,\u76e3\u6e2c\u548c\u7d50\u675fVirtual Circuit(\u865b\u64ec\u96fb\u8def)
3\u8ca0\u8cac\u96fb\u8166\u9593\u4fe1\u606f\u540c\u6b65,\u76e3\u6e2c\u8cc7\u6599\u6e9d\u901a\u72c0\u614b,\u8655\u7406\u932f\u8aa4\u4fe1\u606f
4\u5728\u7db2\u8def\u4e0a\u5340\u5206\u4e0d\u540c\u61c9\u7528\u7684\u8cc7\u6599
\u8207\u6b64\u5c64\u76f8\u95dc\u7684\u6709:NFS,X-window system,appletalk\u4ea4\u8ac7\u5354\u5b9a,netbios,rpc,sql…\u7b49<\/p>\n\n\n\n
\u529f\u80fd:\u78ba\u4fdd\u8cc7\u6599\u6b63\u78ba\u7684\u50b3\u9001\u5230\u76ee\u7684\u5730\u548c\u6c7a\u5b9a\u50b3\u8f38\u9806\u5e8f,\u8cc7\u6599\u6d41\u63a7\u5236,\u591a\u8def\u50b3\u8f38
\u505a\u6cd5:\u5c07\u96fb\u8166data stream\u8b8a\u6210segment\u5f62\u614b\u4e26\u6aa2\u6e2c,\u6216\u91cd\u7d44\u56de\u8cc7\u6599,\u5982\u4e0b
1\u63a5\u7ba1\u4e0a\u5c64\u5354\u5b9a\u50b3\u4f86\u7684\u8cc7\u6599\u9032\u884c”\u5206\u62c6”\u548c”\u6253\u5305”
2\u7528\u9ede\u5c0d\u9ede\u50b3\u9001\u8cc7\u6599\u548c\u56de\u61c9\u7684\u78ba\u8a8d
3\u5f97\u5230\u63a5\u6536\u7aef\u8cc7\u6599\u7de9\u885d\u5340\u98fd\u548c\u4fe1\u606f\u5f8c,\u66ab\u505c\u8cc7\u6599\u767c\u9001
4\u5728\u55ae\u4e00\u4f4d\u5740\u4e0a\u8655\u7406\u4e0d\u540c\u7684\u7a0b\u5f0f\u5354\u5b9a(\u5982ftp\ufe51http\ufe51telnet\u7b49),\u4e26\u5206\u5225\u9032\u884c\u8ffd\u8e64\u53ca\u8f49\u63db
\u6b64\u5c64\u662fOSI\u6700\u91cd\u8981\u7684\u4e00\u5c64,\u662f\u552f\u4e00\u8ca0\u8cac\u7e3d\u9ad4\u7684\u6578\u64da\u50b3\u8f38\u548c\u6578\u64da\u63a7\u5236\u7684\u4e00\u5c64
\u8207\u6b64\u5c64\u76f8\u95dc\u7684\u6709:tcp,udp,spx,netbios,netbeui,socket,…\u7b49<\/p>\n\n\n\n
\u529f\u80fd\uff1a\u8b93packet(\u5c01\u5305)\u5728\u4e0d\u540c\u7684\u7db2\u8def\u4e4b\u9593\u6210\u529f\u5730\u9032\u884c\u50b3\u905e,\u58c5\u585e\u63a7\u5236
\u505a\u6cd5\uff1a\u767c\u9001\u7aef\u50b3\u5c01\u5305\u524d\u5efa\u7acbheader,\u4f5c\u70ba\u7db2\u8def\u9593\u8def\u7531\u4f9d\u64da,\u5982\u4e0b:
1\u898f\u5b9a\u7db2\u8def\u5b9a\u5740\u65b9\u5f0f,\u4e0d\u540c\u7db2\u8def\u9593\u8cc7\u6599\u50b3\u905e\u65b9\u5f0f,\u8655\u7406\u5b50\u7db2\u8def\u9593\u7684\u50b3\u905e,\u6c7a\u5b9a\u8def\u7531\u8def\u5f91,\u7db2\u8def\u74b0\u5883,\u8cc7\u6599\u8655\u7406\u9806\u5e8f,\u7b49\u7b49\u5de5\u4f5c\u3002
2\u8ca0\u8cac MAC\u4f4d\u5740\u548c\u7db2\u8def\u4f4d\u5740(\u5982IP\u4f4d\u5740,IPX\u4f4d\u5740)\u9593\u7684\u89e3\u91cb\u548c\u8f49\u63db
3router\u7de9\u885d\u5340\u98fd\u548c\u6642,\u6703\u901a\u77e5\u6578\u64da\u50b3\u8f38\u8a2d\u5099\u4f7f\u7528\u5176\u5b83\u8def\u5f91\u6216\u66ab\u505c\u767c\u9001\u5c01\u5305(\u58c5\u585e\u63a7\u5236)
4\u5c01\u5305\u9ad4\u7a4d\u8d85\u904erouter\u7684MTU(Maximum Transmission Unit)\u6642,\u5141\u8a31router\u5c0d\u5c01\u5305\u91cd\u7d44\u518d\u50b3
\u8207\u6b64\u5c64\u76f8\u95dc\u7684\u6709:IP,IPX,appletalk,decnet,rip,eigrp,ospf…\u7b49
\u76f8\u95dc\u8a2d\u5099\u6709:router,layer3 switch,…\u7b49
ps:DECnet(Digital Equipment Corperation):DEC\u516c\u53f8\u6240\u63a1\u7528\u7684\u4e00\u7a2e\u7db2\u8def\u5354\u5b9a<\/p>\n\n\n\n
\u529f\u80fd\uff1a\u6307\u5b9a\u4e86\u8981\u63a1\u7528\u7684frame\u683c\u5f0f,\u5efa\u7acb\u8207\u7ba1\u7406\u5169\u500b\u7db2\u8def\u5be6\u9ad4\u9593\u8cc7\u6599\u93c8\u8def
\u505a\u6cd5\uff1a
1\u5236\u5b9a\u4e0d\u540c\u7db2\u8def\u5f62\u614b\u7684frame\u683c\u5f0f,\u8655\u7406\u5be6\u9ad4\u5c64\u7684\u8f49\u63db\u548c\u7ba1\u7406
2\u6d41\u91cf\u63a7\u5236
3\u932f\u8aa4\u5075\u6e2c\u53ca\u66f4\u6b63:\u932f\u8aa4\u6aa2\u6e2c\u65b9\u5f0f,\u907a\u5931\u91cd\u9001,\u78ba\u8a8d,\u4fee\u5fa9\u7a0b\u5e8f,\u4f4d\u5740\u6aa2\u67e5…\u7b49
4\u93c8\u8def\u7684\u5efa\u7acb\u8207\u522a\u9664
5\u5176\u4ed6:\u50b3\u9001\u63a5\u6536\u9806\u5e8f,\u50b3\u905e\u65b9\u5f0f,\u91cd\u7d44\u5206\u754c
\u8207\u6b64\u5c64\u76f8\u95dc\u7684\u6709:ethernet,token ring,isdn,ppp,frame relay,atm,hdlc,…\u7b49
\u76f8\u95dc\u8a2d\u5099\u6709:switch,Physical Address(\u7db2\u5361\u5be6\u9ad4\u4f4d\u5740)
ps:\u56e0\u4f4d\u65bc\u7269\u7406\u5c64\u8207\u7db2\u8def\u5c64\u4e4b\u9593,\u662fOSI\u4e2d\u6bd4\u8f03\u91cd\u8981\u7684\u4e00\u5c64
ps:\u64a5\u63a5\u7528PPP\u5354\u5b9axDLC\u5354\u5b9a\u5728\u6b64\u5c64
ps:Virtual Circuit(\u865b\u64ec\u96fb\u8def)\u9023\u63a5\u548cLogical Link(\u908f\u8f2f\u9023\u7d50)\u7684\u5efa\u7acb\u548c\u7d50\u675f <\/p>\n\n\n\n
\u529f\u80fd:\u7db2\u7d61\u9593\u7684\u8a2d\u5099\u4f48\u7dda,\u786c\u9ad4\u7684\u4fe1\u865f\u8f49\u6210\u96fb\u8166\u7406\u89e3\u7684\u96fb\u5b50\u4fe1\u865f.\u8655\u7406\u5404\u4f4d\u5143\u5728\u5be6\u969b\u7dda\u8def\u7684\u50b3\u9001
\u76f8\u95dc\u8a2d\u5099\u6709:hub,\u7db2\u5361,…\u7b49<\/p>\n","protected":false},"excerpt":{"rendered":"