chapter 4 tcp/ip overview connecting people to information

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Chapter 4 TCP/IP Overview Connecting People To Information Connecting People To Information

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Page 1: Chapter 4 TCP/IP Overview Connecting People To Information

Chapter 4

TCP/IP Overview

Connecting People To InformationConnecting People To Information

Page 2: Chapter 4 TCP/IP Overview Connecting People To Information

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• Early protocol suite

Introduction to TCP/IP

UNIX Host

Internet

TCP/IP

UNIX Host

Page 3: Chapter 4 TCP/IP Overview Connecting People To Information

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• Early protocol suite

• Universal

Introduction to TCP/IP

UNIX Host

Internet

TCP/IP

UNIX Host

Page 4: Chapter 4 TCP/IP Overview Connecting People To Information

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Application Layer Overview

*Used by the router

Application

Transport

Internet

Network Interface

Hardware

File Transfer- TFTP *- FTP- NFS

E-Mail- SMTP

Remote Login- Telnet *- rlogin

Network Management- SNMP *

Name Management- DNS*

File Transfer- TFTP *- FTP- NFS

E-Mail- SMTP

Remote Login- Telnet *- rlogin

Network Management- SNMP *

Name Management- DNS*

Page 5: Chapter 4 TCP/IP Overview Connecting People To Information

Transport Layer

Page 6: Chapter 4 TCP/IP Overview Connecting People To Information

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Transport Layer Overview

Transmission ControlProtocol (TCP)

User Datagram Protocol (UDP)

Transmission ControlProtocol (TCP)

User Datagram Protocol (UDP)

Application

Transport

Internet

Network Interface

Hardware

Page 7: Chapter 4 TCP/IP Overview Connecting People To Information

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TCP Segment Format# Bits 616 32 416 6 32

SourcePort

Dest.Port

SequenceNumber

AcknowledgementNumber

HLEN Reserved CodeBits

16

Window

16

Check-sum

16

Urgent

0 or 32

Option Data...

Page 8: Chapter 4 TCP/IP Overview Connecting People To Information

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Port Numbers

TCP

Port Numbers

FTP

TransportLayer

TELNET

DNS

SNMP

TFTP

SMTP

UDP

ApplicationLayer

21 23 25 53 69 161

Page 9: Chapter 4 TCP/IP Overview Connecting People To Information

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TCP Port Numbers

SourcePort

Dest.Port

Host A

Dest. port = 23.

Send packet to my

Telnet

application.

1028 23 …

SP DP

Host ZTelnet Z

Page 10: Chapter 4 TCP/IP Overview Connecting People To Information

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TCP Handshake/Open Connection

Send SYN (seq=100 ctl=SYN)

SYN received

Send SYN (seq=300 ack=101 ctl=syn,ack)

Established(seq=101 ack=301 ctl=ack)

Host A Host B

Established(seq=101 ack=301 ctl=ack Data)

1

2

3

4

SYN received

Page 11: Chapter 4 TCP/IP Overview Connecting People To Information

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• Window size = 1

Sender Receiver

Send 1Receive 1

Receive ACK 2 Send ACK 2

Send 2Receive 2

Receive ACK 3Send ACK 3

Send 3Receive 3

Receive ACK 4 Send ACK 4

TCP Simple Acknowledgment

Page 12: Chapter 4 TCP/IP Overview Connecting People To Information

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Window size = 3Send 5

Window size = 3Send 2

TCP WindowingSender ReceiverWindow size = 3

Send 1

Window size = 3Send 4

Window size = 3Send 3

ACK 1Window size = 2

ACK 2Window size = 2

ACK 3Window size = 2

ACK 4Window size = 2

ACK 5Window size = 2

Page 13: Chapter 4 TCP/IP Overview Connecting People To Information

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TCP Sequence and Acknowledgment Numbers

I justsent #10.

I just got #10,now I need #11.

Source

Port

Dest.

Port…Sequence

#

Acknowledgement

#

1028 23

Source Dest.

1010

Seq.

1

Ack.

102823Source Dest.

1111Seq.

1Ack.

Page 14: Chapter 4 TCP/IP Overview Connecting People To Information

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TCP Sequence and Acknowledgment Numbers

I justsent #10.

I just got #10,now I need #11.

SourcePort

Dest.Port

…Sequence#

Acknowledgement#

1028 23

Source Dest.

1010

Seq.

1

Ack.

1028 23

Source Dest.

1111

Seq.

2

Ack.

102823

Source Dest.

1111

Seq.

1

Ack.

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• No sequence or acknowledgment fields

UDP Segment Format

16Source

Port

16Destination

Port

16Length

16Checksum Data…

# Bits

Page 16: Chapter 4 TCP/IP Overview Connecting People To Information

Internet Layer

Page 17: Chapter 4 TCP/IP Overview Connecting People To Information

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Network Layer Overview

• OSI network layer corresponds to the TCP/IP internet layer

Internet Protocol (IP)

Internet Control MessageProtocol (ICMP)

Address ResolutionProtocol (ARP)

Reverse AddressResolution Protocol (RARP)

Internet Protocol (IP)

Internet Control MessageProtocol (ICMP)

Address ResolutionProtocol (ARP)

Reverse AddressResolution Protocol (RARP)

Application

Transport

Internet

Network Interface

Hardware

Page 18: Chapter 4 TCP/IP Overview Connecting People To Information

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IP Datagram

# Bits 616 32 416 6 32

VERS HLEN Type ofService

TotalLength

Identi-fication

Flags FragOffset

TTL

4

# Bits 16 32 416 32

Protocol HeaderChecksum

Source IPAddress

Destination IPAddress

IPOptions

Data…

4

Page 19: Chapter 4 TCP/IP Overview Connecting People To Information

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• Determines destination upper-layer protocol

Protocol Field

TransportLayer

InternetLayer

TCP UDP

ProtocolNumbers

IP

176

Page 20: Chapter 4 TCP/IP Overview Connecting People To Information

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Internet Control Message Protocol

Application

Transport

Internet

Network Interface

Hardware

ICMP

Destination Unreachable

Echo (Ping)

Other

Page 21: Chapter 4 TCP/IP Overview Connecting People To Information

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ICMP Testing

• Destination unreachable–Host or port unreachable

–Network unreachable

Host AI do not know how to get to Z.

Send ICMP.

To Z

Destination Unreachable

Send data to Z.

DataNetwork

Page 22: Chapter 4 TCP/IP Overview Connecting People To Information

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ICMP Testing (cont.)

• Generated by the ping command

AYes, I am here.

ICMP Echo Reply

Is B reachable?

B

ICMP Echo Request

Page 23: Chapter 4 TCP/IP Overview Connecting People To Information

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Reverse ARP

• Map Ethernet IP

• ARP and RARP are implemented directly on top of the data link layer

Ethernet: 0800.0020.1111IP: 172.16.3.25

Ethernet: 0800.0020.1111 IP = ???

What is my

IP

address?

I heard that

broadcast.

Your IP

address is

172.16.3.25.