B-基于TCPIP的互連網絡

第二章基于TCP/IP的互連網絡Evan.wu本章目標通過本章的學習，您應該掌握以下內容：了解TCP/IP協議棧，各個分層的主要功能、IP協議的應用

掌握IP地址分類，子網掩碼的作用，識別網絡標識號、主機標識號，子網的數目

IP子網劃分和可變長子網掩碼基本的IP尋址故障排除TCP/IP介紹早期的協議族全球范圍主機InternetTCP/IP主機TCP/IP協議族7654325432應用層表達層會話層傳輸層網絡層數據鏈路層物理層1應用層傳輸層Internet層數據鏈路層物理層1應用層概述*路由器使用應用層傳輸層Internet層數據鏈路層物理層文件傳輸 -TFTP* -FTP* -NFSE-Mail -SMTP遠程登陸 -Telnet* -rlogin*網絡管理 -SNMP*名稱管理 -DNS*傳輸層概述TransmissionControlProtocol(TCP)UserDatagramProtocol(UDP)應用層傳輸層Internet層數據鏈路層物理層面向連接

非面向連接TCP數據格式源端口(16)目標端口(16)序列號(32)報頭長度(4)確認號(32)保留(6)代碼位(6)窗口(16)校驗和(16)緊急(16)選項(0or32ifany)數據(可變)20

Bytes端口號TCP端口號F

T

P傳輸層T

E

L

N

E

TD

N

SS

N

M

PT

F

T

PS

M

T

PUDP應用層2123255369161R

I

P520TCP端口號源端口目標端口…HostA102823…SPDPHostZTelnetZ目標端口=23.

發(fā)送SYN(seq=100ctl=SYN)接收SYNHostAHostBTCP三次握手1發(fā)送SYN(seq=100ctl=SYN)接收SYN發(fā)送SYN,ACK(seq=300ack=101ctl=syn,ack)HostAHostB接收SYN12TCP三次握手發(fā)送SYN(seq=100ctl=SYN)接收SYN發(fā)送SYN,ACK(seq=300ack=101ctl=syn,ack)建立會話(seq=101ack=301ctl=ack)HostAHostB123接收SYNTCP三次握手TCP簡單確認滑動窗口=1發(fā)送方

接收方TCP簡單確認滑動窗口=1發(fā)送方

接收方發(fā)送1接收1TCP簡單確認滑動窗口=1發(fā)送方

接收方發(fā)送1接收1接收ACK2發(fā)送ACK2TCP簡單確認滑動窗口=1發(fā)送方

接收方發(fā)送1接收1接收ACK2發(fā)送ACK2發(fā)送2接收2TCP簡單確認滑動窗口=1發(fā)送方

接收方發(fā)送1接收1接收ACK2發(fā)送ACK2發(fā)送2接收2接收ACK3發(fā)送ACK3TCP簡單確認滑動窗口=1發(fā)送方

接收方發(fā)送1接收1接收ACK2發(fā)送ACK2發(fā)送2接收2接收ACK3發(fā)送ACK3發(fā)送3接收3TCP簡單確認滑動窗口=1發(fā)送方

接收方發(fā)送1接收1接收ACK2發(fā)送ACK2發(fā)送2接收2接收ACK3發(fā)送ACK3發(fā)送3接收3接收ACK4發(fā)送ACK4TCP順序號和確認號源端口目標端口…順序號#確認號#SourceDest.Seq.Ack.102823101我發(fā)送#10.TCP順序號和確認號我已收到#10,現在我需要#11.源端口目標端口…順序號#確認號#102823SourceDest.10Seq.1Ack.102823SourceDest.11Seq.1Ack.我發(fā)送#10.TCP順序號和確認號102823SourceDest.11Seq.2Ack.102823SourceDest.10Seq.1Ack.102823SourceDest.11Seq.1Ack.我已收到#10,現在我需要#11.我發(fā)送#10.源端口目標端口…順序號#確認號#TCP順序號和確認號102823SourceDest.11Seq.2Ack.102823SourceDest.10Seq.1Ack.102823SourceDest.11Seq.1Ack.102823SourceDest.12Seq.2Ack.我已收到#11,現在我需要#12.我發(fā)送#11源端口目標端口…順序號#確認號#TCP窗口發(fā)送方接收方TCP窗口Windowsize=3Send2發(fā)送方接收方Windowsize=3Send1Windowsize=3Send3Windowsize=3Send2TCP窗口發(fā)送方Windowsize=3Send1Windowsize=3Send3ACK3Windowsize=2數據3被丟棄接收方Windowsize=3Send2TCP窗口發(fā)送方Windowsize=3Send1Windowsize=3Send3ACK3Windowsize=2數據3被丟棄Windowsize=3Send4Windowsize=3Send3接收方Windowsize=3Send2TCP窗口發(fā)送方Windowsize=3Send1Windowsize=3Send3ACK3Windowsize=2數據3被丟棄Windowsize=3Send4Windowsize=3Send3ACK5Windowsize=2接收方UDP數據格式沒有順序號和確認號源端口(16)目標端口(16)長度(16)數據(ifany)1Bit0Bit15Bit16Bit31校驗和(16)8

BytesInternet層概述OSI網絡層對應的是TCP/IP的internet層InternetProtocol(IP)InternetControlMessageProtocol(ICMP)AddressResolutionProtocol(ARP)ReverseAddressResolutionProtocol(RARP)應用層傳輸層Internet層數據鏈路層物理層IP數據版本(4)目標IP地址(32)選項(0or32ifany)數據（可變）報頭長度(4)TOS(8)總長度(16)標識(16)標志(3)分段偏移(13)存活期(8)協議(8)報頭校驗和(16)源IP地址(32)20

Bytes協議域決定上層協議Transport

LayerInternet

LayerTCPUDPProtocol

NumbersIP176ICMP協議ApplicationTransportInternetData

LinkPhysicalDestination

UnreachableEcho(Ping)OtherICMP1ARP協議IP:=???我需要知道的物理地址.ARP協議IP:=???我知道你的請求，這是我的物理地址我需要知道的物理地址.ARP協議IP:Ethernet:0800.0020.1111IP:=???我知道你的請求，這是我的物理地址我需要知道的物理地址.ARP協議映射IP MACLocalARPIP:Ethernet:0800.0020.1111IP:=???我知道你的請求，這是我的物理地址我需要知道的物理地址.RARP協議Ethernet:0800.0020.1111IP=???我的地址是多少？RARP協議Ethernet:0800.0020.1111IP=???我的地址是多少？我聽到了廣播你的地址是5.RARP協議Ethernet:0800.0020.1111IP:5Ethernet:0800.0020.1111IP=???我的地址是多少？我聽到了廣播你的地址是5.RARP協議MACIPEthernet:0800.0020.1111IP:5Ethernet:0800.0020.1111IP=???我的地址是多少？我聽到了廣播你的地址是5.TCP/IP地址介紹斷點連接需要確定的地址路徑選擇ocationisrepresentedbyanaddressSADAHDRDATA網絡位主機位1010110000010000

0111101011001100

172

16

122

204128

64

32

16

8

4

2

1

IP地址IP地址屬于網絡層地址，用于標識網絡中的節(jié)點設備IP地址由32bit構成，每8bit一組，共占用4個字節(jié)IP地址由兩部分組成，網絡位和主機位IP地址的分類A類:B類:C類:D類: 多播組編號E類:用于實驗NetworkHostHostHostNetworkNetworkHostHostNetworkNetworkNetworkHost8比特8比特8比特8比特1A類:0NNNNNNNHostHostHost891617242532(1-126)1B類:10NNNNNNNetworkHostHost891617242532(128-191)1C類:110NNNNNNetworkNetworkHost891617242532(192-223)1D類:1110MMMM多播組多播組多播組891617242532(224-239)IP地址的分類私有地址(RFC1918)私有地址的概念屬于非注冊地址，專門為組織機構內部使用私有地址的分類A類:至55B類:至55C類:至55子網掩碼子網掩碼將一個IP地址的網絡位全置為1，主機位全置為0，這樣一個新的地址就是該IP的子網掩碼子網掩碼的作用用于區(qū)分一個IP地址的網絡位和主機位分類地址的子網掩碼A類：/8B類：/16C類：/24主機地址02118E1172.161212網絡主機..網絡端口E0E1路由表E0

11111111計算可用的主機地址172

1600

10101100

00010000

00000000

0000000016

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

網絡主機

00000000

00000001

11111111

11111111

11111111

11111110......

00000000

00000011

11111101123655346553565536-...265534N2N-2=216-2=65534IP地址分類練習地址類別網絡主機004620IP地址分類練習（答案）地址類別網絡主機004620ABCCBNonexistent0046不設子網的地址網絡…...5354設置子網的地址網絡子網地址00600050E0172.16網絡網絡端口E0E1新路由表2160主機..E1子網地址00600050E0E1172.162160網絡主機..網絡端口E0E1新路由表子網十進制和二進制的轉換1 0 0 0 0 0 0 0 = 1281 1 0 0 0 0 0 0 = 1921 1 1 0 0 0 0 0 = 2241 1 1 1 0 0 0 0 = 2401 1 1 1 1 0 0 0 = 2481 1 1 1 1 1 0 0 = 2521 1 1 1 1 1 1 0 = 2541 1 1 1 1 1 1 1 = 255128 64 32 16 8 4 2 116網絡主機172001010110011111111101011000001000011111111000100000000000000000000101000000000000000000000缺省情況下的子網掩碼缺省情況下子網未劃分0000001060

網絡號利用子網掩碼劃分子網擴展了8位地址的網絡16網絡主機6017220101011001111111110101100000100001111111100010000111111110000001010100000000000000000000000000010子網網絡號128192224240248252254255利用子網掩碼劃分子網擴展了10位地址的網絡網絡主機6092101011001111111110101100000100001111111100010000111111110000001010100000110000001000000000000010子網161722128網絡號128192224240248252254255128192224240248252254255子網掩碼練習地址子網掩碼類別子網002子網掩碼練習（答案）地址子網掩碼類別子網002BAA廣播地址55(Directedbroadcast)55(Localnetworkbroadcast)X55(Allsubnetsbroadcast)地址匯總示例16172216010101100000100001010000000000010HostMaskSubnetBroadcastLastFirst609241地址匯總示例1010110011111111000100001111111111111111101000001100000000000010HostMaskSubnetBroadcastLastFirst609212161722160地址匯總示例1010110011111111000100001111111111111111101000001100000000000010HostMaskSubnetBroadcastLastFirst60921237161722160地址匯總示例101011001111111100010000111111111111111110100000110000001000000000000010HostMaskSubnetBroadcastLastFirst60921234161722160地址匯總示例10101100111111110001000011111111111111111010000011000000100000000000001010111111HostMaskSubnetBroadcastLastFirst6092123456161722160地址匯總示例1010110011111111000100001111111111111111101000001100000010000000000000101011111110000001HostMaskSubnetBroadcastLastFirst6092123456161722160地址匯總示例101011001111111100010000111111111111111110100000110000001000000000000010101111111000000110111110HostMaskSubnetBroadcastLastFirst60921234567161722160地址匯總示例101011001111111110101100000100001111111100010000111111110000001010100000110000001000000000000010101011000001000000000010101111111010110000010000000000101000000110101100000100000000001010111110HostMaskSubnetBroadcastLastFirst609212345678161722160地址匯總示例101011001111111110101100000100001111111100010000111111110000001010100000110000001000000000000010101011000001000000000010101111111010110000010000000000101000000110101100000100000000001010111110HostMaskSubnetBroadcastLastFirst609228912990123456789161722160IPHostAddress: 21SubnetMask:B類地址子網規(guī)劃SubnetAddress=HostAddresses=–54BroadcastAddress=55EightbitsofsubnettingNetworkSubnetHost1010110000010000000000101111111121::1010110011111111Subnet:10101100000100000001000011111111000000100000