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Network Communications Technology
Chapter 19Internet Architecture and TCP/IP
Connecting a Network to the Internet
Token Ring
Internal Gateway
Ethernet
InternetExternalGateway
Figure 19.1
NSFNET Backbone (1993)
Figure 19.2
GTE Internet Backbone (2000)
Figure 19.3:
TCP/IP Reference Model
SMTP FTP SNMPTelnet HTTP TFTP
TCP UDP
IPARP
ICMP
RARP
Network Interface Card, or PPP
ApplicationPresentationSession
Transport
Network
Data Link layerPhysical Layer
OSI Model TCP/IP Model
Application LevelTransport Level
InternetLevel
DNS
NetworkLevel
Figure 19.4
TCP/IP Protocols
Internet Protocol (IP) Packet Delivery between Networks
Internet Control Message Transmission and Message Control Protocol (ICMP) between Hosts and Gateways
Address Resolution Protocol Request Physical Address from (ARP) Source
Reverse ARP ARP Response
User Datagram Protocol Best Effort Service (Connectionless, (UDP) no Acknowledgement)
Transmission Control Protocol Reliable Service (Connection) (TCP)
Simple Network Management Diagnostics Protocol (SNMP)
Table 19.1
TCP/IP Application Level
• Simple Mail Transfer Protocol (SMPT, Port 25)
– Send email – POP3 (port 110) for access to received email
• Telnet – Remote login (port 23)
• File Transfer Protocol (FTP, port 20,21, more)
• HTTP – Web Pages (Client/Server, port 80)
• Domain Name System (DNS)
DNS Top-Level Domain Names
More now exist
tv, etc Root
com edu net orggov int mil jp
scsu
cs math
uk
Country
ca
Figure 19.5
UDP Operation
ApplicationTFTP,RPC
UDP Protocol
IP Protocol
NetworkInterface Card
Transmission Media
Data
UDP Header Data
IP Header UDP Header Data
UDP Datagram
IP Datagram
MAC Frame Header IP Datagram FCS
Ethernet or Token Ring Format
Application layer
Transport layer
Network Layer
Data LinkLayer
Figure 19.6
UDP Packet Format
Source Port 16 bitsDefine application TFTP is port 69
Destination Port 16 bitsSpecifies Destination port on server
UDP Length 16 bitsDefine number of bytes in UDP header anddata
Check Sum 16 bitsCheck sum use for error detection of UDPheader and data
DATA
Figure 19.7
TCP OperationApplication
FTP,Telnet,SMTPHTTP
TCP Protocol
IP Protocol
NetworkInterface Card
Transmission Media
Data
TCP Header Data
IP Header TCP Header Data
IP Datagram
MACHeader
IPDatagram
Data
Ethernet or Token Ring Format
Application layer
Transport layer
Network Layer
Link Layer TCP Header
Figure 19.8
TCP Packet Format
Figure 19.9
IP Datagram Packet ProtocolIP VERSION4 bits (currentversion is 4)
Header Length 4 bitsdefine number of 32 bits
word in the header
Type of theService(TOS) 8 bitsspecifies how thedatagram should behandled
Total Lengthspecifies the length ofIP datagram includingthe header in bytes.
Identification16 bits used bydestination to identifydifferent datagramfrom one file
Flags 3 bitscurrently used the first 2 bitsDF and MF bits , DF=1 donot fragment, MF=1 Morefragment is coming
Fragment Offset 13 bitscontains the offset of the fragmentedfrom the beginning of the originaldatagram
Time to Live TTL8 bits specifiesnumber of routers thedatagram can pass
Protocol 8 bitsspecifies the protocol whichdata belongs to such asTCP,UDP,ICMP
Header Checksum 16 bitsthe 16 bit one’s complement sum of theheader
Source IP Address 32 bits IP address of sending machine Destination IP address 32 bits IP address of receiving information Options if Any Padding Data
Figure 19.10
ARP Packet Format
Hardware Type 16 bits Protocol Type 16 bitsHLEN Hardware address Length 8 bits PLEN IP address Length 8 bits
Operation Code 16 bits ARP Request =1 ARP Response =2 RARP Request=3 RARP response =4
Sender Hardware Address48 bits
Sender IP Address32 bits
Target Hardware Address48 bits
Target IP Address32 bits
Figure 19.11
ARP / RARP
32 bit Internet Address
AR
P
RA
RP
48-bit Ethernet Address
Figure 19.12:
IPv4
MAC
A Network
Figure: 19.13
Token Ring
ExternalGateway
InternalGateway
129.47.3.1 129.47.3.3
129.47.3.2
129.47.3.5129.47.3.6
129.47.3.7
129.47.3.4
BiologyDepartment
129.47.3
Computer ScienceDepartment
129.47.1.2
129.47.1.3129.47.1.5 129.47.1.1
129.47.1.4129.47.1
129.47.2.1
129.47.2.2
129.47.2.3
129.47.2.4
129.47.2.5
129.47.2
MathematicsDepartment
IPv4 Addresses
• Class A – 1.0.0.0 to 126.255.255.255– 126 large organizations (all gone)
• Class B – 128.0.0.0 to 191.255.255.255 – 214 networks each with 216 hosts
• Class C – 192.0.0.0 to 223.255.255.255– 221 small networks , 255 hosts
Address Mask
• Separates a network address from the Host address
Figure: 19.14
11111111 11111111 11111111 00000000
255 255 255 0. . .
2 bytes 1 byte 1 byte
Network ID Sub ID Host IDBinary
DottedDecimal
Point-to-Point ProtocolPacket Format
Flag7E
AddressFF
Control03
for PPP
Protocol type0021 means information is IP
datagram
Information FCS Flag7E
1 byte 1 byte 1 byte 2 bytes 0-1500 Bytes 2 bytes 1 byte
Figure 19.15
Demultiplexing Information
Figure 19.16:
IPRARP ARP
UDP
Network Interface Card
MAC Header IP TCP Interface FCS
TCP
ApplicationApplication
IP TCP if Any Information
Setting up a TCP Connection
Figure 19.17:
Source Destination
SYN = 1seq x
SYN = 1ACK x + 1Seq y
Receive andsend ACK x+1
Send data seq x +1ACK y + 1
Send ACK y +1
Receive ACK
Disconnecting a TCP Connection
Figure 19.18:
FIN = 1seq = x
send ACK x+1 send FIN seq = y
RS=1 Seq X+1
RS=1 ACK X+2
Send ACK y +1
Send FINseq = x
Source Destination
IPv6 Format
Figure 19.19:
1 4 5 8 9 32
BasicHeader
VERSION 4 bits FLOW LABLEVersion Number is 6 priority Specifies the type of the information in payload field
such as speech, video information, data
PAY LOAD LENGTH 16 bits NEXT HEADER 8 bits HOP LIMIT 8 bitsIndicates the number of bytes determines which header the function is thein payload fields follows basic IP header same as TTL for IPv4
SOURCE ADDRESS 128 bits
DESTINATION ADDRESS 128 bits
EXTENTION HEADER
PayloadMaximum size of payload is 64K bytes
IP Datagram Extension Headers
Figure 19.20:
Version Priority Flow labelPayload length Next Header 0 Hop limit Source Address
Destination Address
Next header 43 Header length Hop by Hop options
Next Header 06 Header Length
Routing Information TCP Header and data
IPv6 Unicast Address
Figure 19.21:
3 bits 5 bits 16 bits 16 bits 8bits 32 bits 48 bits
Format prefix Registry ID Provider ID Subscriber type Subscriber ID Sub-network ID Interface ID
MAC
IPv4 to IPv6 Migration
Figure 19.22a:IPv4 Imbedded in IPv6
Figure 19.22b:For Station w/o
IPv6 Support
vBNS Backbone (2000)
Figure 19.23: