電腦網絡精編教程 — 原理與實踐

第 1 章 概述............................................................................................................................................1
1.1 電腦網絡簡介 ...................................................................................................................1
1.1.1 電腦網絡的定義 ...................................................................................................1
1.1.2 電腦網絡的分類 ...................................................................................................3
1.1.3 互聯網邊緣部分 .......................................................................................................5
1.1.4 互聯網核心部分 .......................................................................................................6
1.2 電腦網絡的性能指標 .......................................................................................................8
1.2.1 速率...........................................................................................................................8
1.2.2 帶寬...........................................................................................................................9
1.2.3 時延（delay） ........................................................................................................12
1.2.4 吞吐量.....................................................................................................................15
1.2.5 丟包率.....................................................................................................................18
1.3 電腦網絡體系結構 .........................................................................................................18
1.3.1 分層的體系結構 .....................................................................................................18
1.3.2 協議與分層.............................................................................................................20
1.3.3 TCP/IP 體系結構 ....................................................................................................26
1.4 互聯網的發展 .....................................................................................................................28
1.4.1 互聯網的起源.........................................................................................................28
1.4.2 TCP/IP 互聯網的根基 ............................................................................................29
1.4.3 NSF 互聯網的推進者.............................................................................................30
1.4.4 WWW：互聯網的“分水嶺”..............................................................................30
1.4.5 移動互聯網.............................................................................................................31
1.5 本章實驗.............................................................................................................................32
1.5.1 實驗環境配置.........................................................................................................32
1.5.2 協議封裝.................................................................................................................34
1.5.3 越層封裝.................................................................................................................36
習題 .............................................................................................................................................40
第 2 章 直連網絡..................................................................................................................................43
2.1 直連網絡.............................................................................................................................43
2.1.1 直連網絡的概念 .....................................................................................................43
2.1.2 直連網絡的數據傳輸 .............................................................................................44
2.1.3 直連網絡的硬件組成 .............................................................................................45
2.1.4 導向傳輸媒體.........................................................................................................46
2.1.5 非導向傳輸媒體 .....................................................................................................53
2.2 編碼.....................................................................................................................................57
2.2.1 不歸零編碼 NRZ（Non-Return to Zero）.............................................................58
2.2.2 曼徹斯特編碼（Manchester Encoding）...............................................................59
2.2.3 差分曼徹斯特編碼（Differential Manchester Encoding） ...................................59
2.3 成幀.....................................................................................................................................60
2.3.1 面向字符的協議 PPP..............................................................................................60
2.3.2 面向比特的協議 HDLC .........................................................................................65
2.4 差錯檢測.............................................................................................................................68
2.5 廣播式以太網 .....................................................................................................................70
2.5.1 以太網標準.............................................................................................................70
2.5.2 以太網 MAC 幀......................................................................................................72
2.5.3 以太網 MAC 地址..................................................................................................74
2.5.4 傳輸媒體接入控制 .................................................................................................76
2.5.5 10BASE-T 網絡......................................................................................................83
2.6 交換機.................................................................................................................................84
2.6.1 交換機概述.............................................................................................................84
2.6.2 交換機 MAC 地址學習 ..........................................................................................85
2.6.3 虛擬局域網 VLAN .................................................................................................87
2.7 高速以太網.........................................................................................................................91
2.7.1 快速以太網.............................................................................................................91
2.7.2 吉比特以太網.........................................................................................................94
2.7.3 10 吉比特以太網 ....................................................................................................95
2.7.4 40 吉比特以太網（40GbE）.................................................................................96
2.8 本章實驗.............................................................................................................................98
2.8.1 虛擬局域網.............................................................................................................98
2.8.2 交換機 MAC 地址學習 ........................................................................................103
2.8.3 幀的發送與接收 ...................................................................................................104
習題 ...........................................................................................................................................106
第 3 章 網絡互連................................................................................................................................109
3.1 互連網絡...........................................................................................................................109
3.1.1 互連網絡的概念 ...................................................................................................109
3.1.2 路由器...................................................................................................................113
3.1.3 集線器、交換機和路由器 ...................................................................................116
3.2 網際協議 IP.......................................................................................................................118
3.2.1 IPv4 編址...............................................................................................................119
3.2.2 劃分子網........................................................................................................................125
3.2.3 路由表與轉發表 ...................................................................................................129
3.2.4 路由器分組轉發 ...................................................................................................131
3.2.5 DHCP 協議 ...........................................................................................................135
3.2.6 地址解析協議 ARP ..............................................................................................141
3.2.7 網絡地址轉換 NAT ..............................................................................................145
3.2.8 IP 分組的格式.......................................................................................................147
3.2.9 網際控制報文協議 ICMP.....................................................................................152
3.3 路由選擇協議 ...................................................................................................................160
3.3.1 概述.......................................................................................................................160
3.3.2 內部網關協議 RIP................................................................................................162
3.3.3 內部網關協議 OSPF.............................................................................................170
3.3.4 外部網關協議 BGP ..............................................................................................182
3.4 多協議標簽交換 MPLS....................................................................................................199
3.4.1 概述.......................................................................................................................199
3.4.2 MPLS 中的幾個基本概念....................................................................................200
3.4.3 MPLS 的基本操作................................................................................................202
3.4.4 標簽分發協議 LDP...............................................................................................204
3.5 IPV6 ...................................................................................................................................216
3.5.1 概述.......................................................................................................................216
3.5.2 IPv6 分組的格式...................................................................................................216
3.5.3 IPv6 地址...............................................................................................................220
3.5.4 ICMPv6 .................................................................................................................226
3.5.5 鄰站發現協議 NDP ..............................................................................................228
3.5.6 重復地址檢測 DAD..............................................................................................234
3.6 本章實驗...........................................................................................................................236
3.6.1 獨臂路由接入互連網絡 .......................................................................................236
3.6.2 DHCP 與 NAT.......................................................................................................240
3.6.3 單區域的 OSPF 的配置........................................................................................245
3.6.4 簡單的路由追蹤程序的實現 ...............................................................................248
3.6.5 ARP 協議實現活動主機的探測...........................................................................249
習題 ...........................................................................................................................................252
第 4 章 端到端的通信........................................................................................................................259
4.1 端到端的概念 ...................................................................................................................259
4.1.1 端系統與網絡層 ...................................................................................................259
4.1.2 埠的概念...........................................................................................................261
4.1.3 埠監聽的概念 ...................................................................................................262
4.2 UDP...................................................................................................................................263
4.2.1 概述.......................................................................................................................263
4.2.2 UDP 的特點..........................................................................................................263
4.2.3 UDP 報文的格式 ..................................................................................................265
4.3 TCP....................................................................................................................................267
4.3.1 TCP 概述...............................................................................................................268
4.3.2 TCP 連接的概念...................................................................................................270
4.3.2 TCP 可靠的傳輸...................................................................................................271
4.3.4 TCP 報文段的格式...............................................................................................275
4.3.5 發送 TCP 報文段的時機......................................................................................281
4.3.6 TCP 超時重傳時間...............................................................................................284
4.3.6 TCP 流量控制.......................................................................................................287
4.3.7 TCP 擁塞控制.......................................................................................................293
4.3.8 主動隊列管理 AQM.............................................................................................302
4.3.9 TCP 連接管理.......................................................................................................303
4.3.10 TCP 連接的管理模型.........................................................................................308
4.3.11 TCP 定時器.........................................................................................................311
4.4 TCP 與 UDP 的區別.........................................................................................................311
4.5 本章實驗...........................................................................................................................312
4.5.1 Socket 程序 ...........................................................................................................313
4.5.2 通用的建立 TCP 連接的程序..............................................................................318
4.5.3 埠掃描程序.......................................................................................................323
習題 ...........................................................................................................................................329
第 5 章 互聯網應用層協議................................................................................................................334
5.1 域名系統 DNS ..................................................................................................................334
5.1.1 概述.......................................................................................................................334
5.1.2 域名空間...............................................................................................................335
5.1.3 資源記錄...............................................................................................................337
5.1.4 域名服務器...........................................................................................................341
5.1.5 域名的解析過程 ...................................................................................................344
5.1.6 DNS 報文的格式 ..................................................................................................348
5.2 WEB 與 HTTP....................................................................................................................353
5.2.1 HTTP 協議............................................................................................................353
5.2.2 HTTP 報文的格式 ................................................................................................359
5.2.3 代理服務器...........................................................................................................362
5.2.4 數據同步...............................................................................................................364
5.3 文件傳輸協議 FTP ...........................................................................................................369
5.3.1 概述.......................................................................................................................369
5.3.2 FTP 的工作方式 ...................................................................................................369
5.3.3 FTP 會話 ...............................................................................................................373
5.4 簡單文件傳輸協議 TFTP.................................................................................................374
5.4.1 概述.......................................................................................................................374
5.4.2 TFTP 分組的格式.................................................................................................375
5.4.3 TFTP 實例分析.....................................................................................................377
5.5 遠程登錄 TELNET..............................................................................................................379
5.5.1 網絡虛擬終端 NVT..............................................................................................379
5.5.2 Telnet 控制命令 ....................................................................................................380
5.5.3 選項協商...............................................................................................................381
5.5.4 Telnet 的使用 ........................................................................................................384
5.5.5 Telnet 傳輸效率 ....................................................................................................386
5.5.6 NVT 的安全性......................................................................................................387
5.6 電子郵件 EMAIL................................................................................................................388
5.6.1 概述.......................................................................................................................388
5.6.2 簡單郵件傳輸協議 SMTP....................................................................................389
5.6.3 電子郵件的基本格式 ...........................................................................................392
5.6.4 郵局訪問協議 POP3.............................................................................................393
5.6.5 基於 Web 的電子郵件..........................................................................................399
5.6.6 通用互聯網郵件擴充 MIME ...............................................................................400
5.7 本章實驗...........................................................................................................................404
5.7.1 VMware 中安裝 Ubuntu 22.04 LTS .....................................................................404
5.7.2 安裝配置 DNS ......................................................................................................405
5.7.3 安裝配置 Web 服務..............................................................................................411
5.7.4 域名解析客戶程序設計 .......................................................................................419
習題 ...........................................................................................................................................423
附錄 A 電腦網絡常用縮略詞 ........................................................................................................427
參考文獻................................................................................................................................................431