[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-1-en-105":3,"doc-seo-572706-105":53,"doc-detail-572706-en":127},{"code":4,"msg":5,"data":6},0,"success",[7,14,19,24,29,34,39,44,49],{"id":8,"doc_module":9,"doc_module_name":10,"category_name":11,"show_sort_weight":12,"slug":13},11,1,"Template","Presentations",90,"presentations",{"id":15,"doc_module":9,"doc_module_name":10,"category_name":16,"show_sort_weight":17,"slug":18},12,"Resumes",80,"resumes",{"id":20,"doc_module":9,"doc_module_name":10,"category_name":21,"show_sort_weight":22,"slug":23},14,"Invoices",70,"invoices",{"id":25,"doc_module":9,"doc_module_name":10,"category_name":26,"show_sort_weight":27,"slug":28},15,"Posters",60,"posters",{"id":30,"doc_module":9,"doc_module_name":10,"category_name":31,"show_sort_weight":32,"slug":33},16,"Social Media",50,"social-media",{"id":35,"doc_module":9,"doc_module_name":10,"category_name":36,"show_sort_weight":37,"slug":38},17,"Forms",40,"forms",{"id":40,"doc_module":9,"doc_module_name":10,"category_name":41,"show_sort_weight":42,"slug":43},18,"Letters",30,"letters",{"id":45,"doc_module":9,"doc_module_name":10,"category_name":46,"show_sort_weight":47,"slug":48},21,"Paper Templates",5,"papers-templates",{"id":50,"doc_module":9,"doc_module_name":10,"category_name":51,"show_sort_weight":4,"slug":52},158,"General","general-158",{"code":4,"msg":54,"data":55},"ok",{"site_id":56,"language":57,"slug":58,"title":59,"keywords":60,"description":61,"schema_data":62,"social_meta":120,"head_meta":122,"extra_data":124,"updated_unix":126},105,"en","ethernet-and-ip-goals-osi-layers-encapsulation-troubleshooting","Ethernet and IP: Goals, OSI Layers, Encapsulation, Troubleshooting","","Ethernet and IP讲义围绕一次入门到中阶的网络课程目标展开，重点说明以OSI分层与简化层模型理解网络：应用层到物理/数据层的职责边界，以及为何常把四层以下统称为“packet”。内容涵盖封装关系（Ethernet帧、IP分组、TCP/UDP数据单元）、各层字段含义（端口、IP地址、校验与CRC）和常见以太网故障排查：物理连接、速率/双工不匹配、MDI/MDIX与自动协商失败等，并简述IP寻址与子网掩码/CIDR的角色。",{"@graph":63,"@context":119},[64,80,102],{"@type":65,"itemListElement":66},"BreadcrumbList",[67,71,74,77],{"item":68,"name":69,"@type":70,"position":9},"https://docshare.wps.com","Home","ListItem",{"item":72,"name":10,"@type":70,"position":73},"https://docshare.wps.com/template/",2,{"item":75,"name":11,"@type":70,"position":76},"https://docshare.wps.com/template/presentations/",3,{"item":78,"name":59,"@type":70,"position":79},"https://docshare.wps.com/template/ethernet-and-ip-goals-osi-layers-encapsulation-troubleshooting/572706/",4,{"url":78,"name":59,"@type":81,"image":82,"author":87,"headline":59,"publisher":90,"fileFormat":93,"inLanguage":57,"description":61,"dateModified":94,"datePublished":95,"encodingFormat":93,"isAccessibleForFree":96,"interactionStatistic":97},"DigitalDocument",{"url":83,"@type":84,"width":85,"height":86},"https://docshare.wps.com/thumbnails/ethernet-and-ip-goals-osi-layers-encapsulation-troubleshooting/572706.png","ImageObject",442,249,{"name":88,"@type":89},"Aurelia","Person",{"url":68,"name":91,"@type":92},"DocShare","Organization","application/pdf","2026-10-21","2026-10-13",true,{"@type":98,"interactionType":99,"userInteractionCount":101},"InteractionCounter",{"@type":100},"ViewAction",8,{"@type":103,"mainEntity":104},"FAQPage",[105,111,115],{"name":106,"@type":107,"acceptedAnswer":108},"本讲义的课程目标包括哪些重点？","Question",{"text":109,"@type":110},"主要目标是更深入理解以太网，并掌握IP相关内容（如TCP/UDP、ARP、ICMP、IP寻址与子网掩码），同时学习排查以太网与IP问题。","Answer",{"name":112,"@type":107,"acceptedAnswer":113},"为什么讲义会强调“封装（Encapsulation）”与各层职责边界？",{"text":114,"@type":110},"讲义用邮政系统类比说明：每一层只负责自己的工作并把结果交给下一层，从而避免重复处理更上/下层的内容。",{"name":116,"@type":107,"acceptedAnswer":117},"常见以太网问题有哪些排查方向？",{"text":118,"@type":110},"包括物理层连接是否正常（是否插好/是否损坏）、速率是否匹配、双工模式是否匹配，以及在交换机到交换机或电脑到电脑连接时MDI/MDIX导致的交叉/直连线问题。","https://schema.org",{"og:url":78,"og:type":121,"og:title":59,"og:site_name":91,"og:description":61},"article",{"robots":123,"canonical":78},"index,follow",{"doc_id":125,"site_id":56},572706,1792033411,{"code":4,"msg":5,"data":128},{"doc_id":125,"user_id":129,"nickname":88,"user_avatar":130,"doc_module":9,"category_id":8,"category_name":11,"doc_title":59,"doc_description":61,"doc_content":131,"file_id":132,"file_url":133,"file_type":134,"file_size":135,"view_count":101,"is_deleted":4,"is_public":9,"is_downloadable":9,"audit_status":9,"page_count":136,"language":137,"language_code":57,"site_id":56,"html_lang":57,"table_of_contents":138,"faqs":139,"seo_title":140,"seo_description":61,"update_tm":141,"read_time":142},1099514068365,"https://ap-avatar.wpscdn.com/avatar/10000253d8d9f28188e?_k=1776742907772140068","Ethernet and IPA slightly less introductory networking class  \nDrew Saunders Networking Systems Stanford University  \nGoals of Class  \n• Slightly more in-depth knowledge of Ethernet.  \n• Internet Protocol, TCP, UDP, ARP, ICMP.  \n• IP addressing, subnet masks.  \n• Some troubleshooting of ethernet and IP problems.  \nNot goals of class  \n• Detailed understanding of TCP/IP.  \n• Server or desktop maintenance or configuration.  \n• How to use email, web, etc.  \n• Routing, SUNet details.  \nOur friend, the 7-layer networking model.  \n7  \n6  \n5  \n4  \n3  \n2  \n1  \nOSI 7-layer model  \n\n| Application |\n| --- |\n| Presentation |\n| Session |\n| Transport |\n| Network |\n| Data |\n| Physical |\n\nDOD 3-layer model  \n\n| Application |\n| --- |\n| Protocol |\n| Local Network\u003Cbr>(LAN) |\n\nSimplified 4/5-layer model  \n\n| Application |\n| --- |\n| Transport |\n| Network |\n| Data |\n| Physical |\n\nData Unit Name  \nData  \nSegments  \nPackets  \nFrames  \nBits  \nWhat“lives”  \nhere?  \nApplications  \nSoftware, Firewalls  \nRouters, Firewalls  \nSwitches, Hubs, WAPs  \nCables, Microwaves  \nOSI (Open Systems Interconnection) mnemonic: All People Seem To Need Data Processing We’ll be using the “simplified model,” and talking mostly about the Network (IP) and Transport (TCP and UDP) layers, plus a little about Data (Ethernet details) .  \nAlthough not strictly correct, people tend to call everything from layer 4 down a “packet.”  \nNetworking layers compared to  \nthe postal system.  \n• What are you sending? (Application)  \n• Where am I going? (Addressing, DNS)  \n• How do I get there? (Routing)  \n• What am I packaged in? (Network, Data)  \n• What carries me? (Data, Physical)  \n• What are the traffic rules on my road/train/flight?(Data, Physical)  \nEncapsulation  \nApplication  \nData  \nTCP (Transport  \nLayer)  \n| Dest. TCP Port | Source TCP Port | Data | Error Checking |\n| --- | --- | --- | --- |\n\nIP  \n(Network Layer)  \n| Header | Dest. IP Address | Source IP Address | \u003Cbr>Data\u003Cbr>|\n| --- | --- | --- | --- |\n\nEthernet (Data Layer)  \n\n| |  |  |  |\n| --- | --- | --- | --- |\n| Dest. HWAddr. | Source HWAddr | Data | CRC Error Checking |\n\nPostal system: Letter (Application) gets letterhead (TCP) gets put in an envelope (IP) gets put in a mail bag (Ethernet) gets carried on a mail truck (Cat5, wireless, etc. -Physical layer)  \nEach layer doesn’t have to worry about all the contents inside, each layer can handle its own job and pass it on to the next destination, i.e.: the post office can move whole bags without having to look at each letterhead on each letter in each envelope every time.  \nMore on Ethernet  \n\n| Preamble | Dest. HW\u003Cbr>Addr. | Source HWAddr | Type | Data | CRC Error Checking |\n| --- | --- | --- | --- | --- | --- |\n\n• Preamble: 64 alternating 0’s and 1’s to synchronize the computers.  \n• Destination: 48-bit (usually done as 12 hex characters) address of the intended receiver, all 1’s (FFFF...) for broadcast.  \n• Source: Your own HW address.  \n• Type: Ethernet II is the only type really used any more, there are 3 others for legacy Layer 3 protocols (Appletalk, IPX, etc.)  \n• Data: The contents, which aren’t the concern of the ethernet layer, but are to be handed off to the next layer.  \n• CRC: Cyclic Redundancy Check. When the computer builds the packet, it does some math based on the packet (which is, after all, just 0’s and 1’s) and puts the result of that calculation at the end. If the receiver does the same math and gets a different result, the packet is rejected and an error is sent back to the sender.  \nCommon Ethernet Problems  \n• Physical layer: Is the cable plugged in? Is it broken? Did someone run their chair over it for the last time?“It worked fine yesterday!”  \n• Speed mis-match. Most modern computers and network equipment can speak at either 10Mbps or 100Mbps or 1000Mbps, but each end has to agree. Auto-negotiation may fail, so one end or both may have to be forced to a specific speed.  \n• Duplex mis-match. Most modern computers and network equipment usefull duplex only (they ","cbCaiaRd2kRGBbH1","https://ap.wps.com/l/cbCaiaRd2kRGBbH1","pdf",5982981,27,"English","# Goals of Class\n# OSI 7-layer, DOD 3-layer, and Simplified 4/5-layer models\n# Data unit names: bits, data, segments, packets, frames\n# Encapsulation: TCP, IP, Ethernet\n## TCP transport layer fields\n## IP network layer fields\n## Ethernet data layer fields\n# More on Ethernet (header components and CRC)\n# Common Ethernet Problems\n## Physical layer connection issues\n## Speed mismatch\n## Duplex mismatch\n## MDI/MDIX problem\n# IP Packet and Header details\n# IP Addressing and subnet masks/CIDR","[{\"question\":\"本讲义的课程目标包括哪些重点？\",\"answer\":\"主要目标是更深入理解以太网，并掌握IP相关内容（如TCP/UDP、ARP、ICMP、IP寻址与子网掩码），同时学习排查以太网与IP问题。\"},{\"question\":\"为什么讲义会强调“封装（Encapsulation）”与各层职责边界？\",\"answer\":\"讲义用邮政系统类比说明：每一层只负责自己的工作并把结果交给下一层，从而避免重复处理更上/下层的内容。\"},{\"question\":\"常见以太网问题有哪些排查方向？\",\"answer\":\"包括物理层连接是否正常（是否插好/是否损坏）、速率是否匹配、双工模式是否匹配，以及在交换机到交换机或电脑到电脑连接时MDI/MDIX导致的交叉/直连线问题。\"}]","Ethernet and IP: Goals, OSI Layers, Encapsulation, Troubleshooting | PDF",1791928951,9]