TCP/IP Model

puffyyaphankyonkersΔίκτυα και Επικοινωνίες

26 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

71 εμφανίσεις

9.
1

©

2004 by Prentice Hall

9

THE INTERNET AND THE


NEW INFORMATION

TECHNOLOGY

INFRASTRUCTURE

** MODIFIED **

Chapter


9.
2

©

2004 by Prentice Hall

The New Information Technology (IT) Infrastructure

Figure 9
-
1

9.
3

©

2004 by Prentice Hall

Connectivity



Measures how well computers and
computer
-
based devices communicate


Open System




Software systems / not proprietary



Operate on different hardware platforms

Standards and Connectivity for Digital Integration

9.
4

©

2004 by Prentice Hall

Models of Connectivity for Networks



Transmission Control
Protocol/Internet Protocol (TCP/IP)



Open Systems Interconnect (OSI)




Standards and Connectivity for Digital Integration

9.
5

©

2004 by Prentice Hall

(TCP/IP) Reference Model

Figure 9
-
2

9.
6

©

2004 by Prentice Hall

More on
Network

Protocols

Protocol

Rules network uses to transfer data


9.
7

©

2004 by Prentice Hall

TCP/IP


Transmission
Control
Protocol/Intern
et Protocol
(TCP/IP)


Suite of small,
specialized
protocols
called
subprotocols

OSI Model

TCP/IP

Figure 3
-
1: TCP/IP compared to the OSI Model

9.
8

©

2004 by Prentice Hall

Internet Protocol (IP)


Provides information about how and
where data should be delivered


Subprotocol that enables TCP/IP to
internetwork


To internetwork is to traverse more than one
LAN segment and more than one type of
network through a router


In an internetwork, the individual networks
that are joined together are called
subnetworks

9.
9

©

2004 by Prentice Hall

Internet Protocol (IP)

data format

Figure 3
-
2: Components of an IP datagram

9.
10

©

2004 by Prentice Hall

Internet Protocol (IP)


IP datagram



IP portion of TCP/IP frame that acts as an envelope
for data


Contains information necessary for routers to
transfer data between subnets

Figure 3
-
2: Components of an IP datagram

9.
11

©

2004 by Prentice Hall

Internet Protocol (IP)


IP is an unreliable, connectionless
protocol, which means it does not
guarantee delivery of data


Connectionless


Allows protocol to service a request without
requesting verified session and without
guaranteeing delivery of data

9.
12

©

2004 by Prentice Hall

Transport Control Protocol (TCP)


TCP


Provides reliable data delivery services


Connection
-
oriented

subprotocol


Requires establishment of connection
between communicating nodes before
protocol will transmit data


TCP segment


Holds TCP data fields


Becomes encapsulated by IP datagram

9.
13

©

2004 by Prentice Hall

Transport Control Protocol (TCP)

data format


Port


Address on host where application makes itself
available to incoming data

Figure 3
-
3:
A TCP
segment

9.
14

©

2004 by Prentice Hall

Encapsulate TCP inside IP

TPC information + message

Connection oriented &

reliable



IP datagram has Source IP ADDRESS and

destination IP ADDRESS

It is

Connectionless & unreliable

9.
15

©

2004 by Prentice Hall

Addressing in TCP/IP


An IP Address looks like this


203.188.65.109


The values between periods are called
“octets”


Each octet is a number between 0 and 255


The total number of octets is 4


Total number of bits is 4 x 8 = 32


Maximum number of address is 2^32

9.
16

©

2004 by Prentice Hall

Addressing in TCP/IP


Remember a byte (8 bits) can have


00000000 to 11111111 unique
values


Or 0 to 255


We would rather work with decimal
numbers than binary numbers


So, 124.345.50.333 is invalid, why?


9.
17

©

2004 by Prentice Hall

Addressing in TCP/IP


How many addresses can be made
starting with these octets: 203.188.65.X



203.188.65.0


203.188.65.1


203.188.65.2


………


203.188.65.255



9.
18

©

2004 by Prentice Hall

Viewing Current IP Information

command:
ipconfig /all

9.
19

©

2004 by Prentice Hall

Addressing in TCP/IP


Though 8 bits have 256 possible combinations,
only the numbers 1 through 254 are used to
identify networks and hosts


Numbers 0 and 255 are reserved for
broadcasts


Broadcast are transmissions to all stations on a network

Table 3
-
1: Commonly used TCP/IP classes

9.
20

©

2004 by Prentice Hall

Figure 9
-
4

Addressing in TCP/IP

Analysis of an Internet Address


9.
21

©

2004 by Prentice Hall

Domain Names

Table 11
-
3: Domain naming conventions

9.
22

©

2004 by Prentice Hall

Addressing in TCP/IP

Analysis of an Internet Address


9.
23

©

2004 by Prentice Hall

Addressing in TCP/IP


The domain names are IP
Addresses!!!



www.prenhall.com

= 198.4.159.10



Cool Trick: Go to command prompt and
type:
WHOIS 198.4.159.10

9.
24

©

2004 by Prentice Hall

Addressing in TCP/IP

9.
25

©

2004 by Prentice Hall

Addressing in TCP/IP


With IP ADDRESS background we
can easily answer


Firewalls


How ISPs work (dynamic static)


Extranets, Intranets


9.
26

©

2004 by Prentice Hall

Firewall

= Restricts IP Addresses


Firewall


Specialized device (typically a router)


Selectively filters or blocks traffic between
networks


May be strictly hardware
-
based or may
involve a combination of hardware and
software


Host


Computer connected to a network using
the TCP/IP protocol

9.
27

©

2004 by Prentice Hall

Firewall

= Restricts IP Addresses

ROUTER blocks all IP address except 166.144.x.x

9.
28

©

2004 by Prentice Hall

Internet Service Provider (ISP)


Commercial organization with a permanent
connection to Internet


They “bought” a bunch of IP Addresses


They kept some permanent


Lend most of the IP Address out to customers


i.e. people wanting internet access!


Maybe 50,000 customers, but only 10, 000 IP
Addresses


Analogy: towels at the gym


Internet Service Provider (ISP)


9.
29

©

2004 by Prentice Hall

Internet Service Provider (ISP)



Static IP address (Web Sites)


IP address manually assigned to a
device


Dynamic Host Configuration Protocol
(DHCP)
---
(consumer logging on to
ISP)


Manages dynamic distribution of IP
addresses on a network

9.
30

©

2004 by Prentice Hall

Model of an Extranet

Figure 9
-
6

Controlling Access too different Networks

Extranets, Intranets……

9.
31

©

2004 by Prentice Hall

Controlling Access too different Networks

Extranets, Intranets……

9.
32

©

2004 by Prentice Hall

Figure 9
-
3

Client/Server Computing on the Internet

9.
33

©

2004 by Prentice Hall

LISTSERV



E
-
mail broadcast from mailing list
servers


Chatting


Live, interactive conversations over
public network





Internet Tools for Communication

9.
34

©

2004 by Prentice Hall


Instant messaging


Service that allows participants to
create their own private chat channels


Internet telephony


Two
-
way voice transmission over the
Internet


Internet Tools for Communication

9.
35

©

2004 by Prentice Hall

Figure 9
-
5

GATEWAY

SERVERS

GATEWAY

How are you?

( )

A

B

C

How are you?

( )

A

B

C

Fine, thank you!

( )

X

Y

Z

Fine, thank you!

( )

X

Y

Z

A

B

C

X

A

Y

B

Z

C

B

C

A

Y

Z

X

X

Y

Z

Internet Tools for Communication

Good example of packet switching

9.
36

©

2004 by Prentice Hall

Telnet


Allows users to log on to one
computer system while working on
another


File Transfer Protocol (FTP)


Tool for retrieving and transferring
files from a remote computer

Internet Tools for Communication

9.
37

©

2004 by Prentice Hall

TCP/IP Application Layer Protocols


Telnet


Used to log on to remote hosts using TCP/IP
protocol suite


File Transfer Protocol (FTP)


Used to send and receive files via TCP/IP


Simple Mail Transfer Protocol (SMTP)


Responsible for moving messages from one e
-
mail
server to another, using the Internet and other
TCP/IP
-
based networks


Simple Network Management Protocol
(SNMP)


Manages devices on a TCP/IP network