TCP/IP – Transmission Control Protocol/ Internet Protocol

In this presentation, we will discuss in details about the TCP/ IP framework, the backbone of every ebusiness.
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1. Transmission Control Protocol
(TCP) / Internet Protocol (IP)

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2. Overview of TCP/IP

Oldest networking standard developed for US
department’s ARPANET

Most popular network protocol

Allows reasonably efficient and error — free
transmission

A file transfer protocol , sends large files
uncorrupted across unreliable networks
Compatible with a variety of data link protocols
hence popular

3. An Internet

A, B, C, D, E, F —host (computers)
1, 2, 3, 4, 5 — physical networks

a, b, c, d, e, f — routers/gateways

For TCP/IP, the same internet appears differently. TCP/IP considers all
interconnected. physical networks as one huge network (1+2:

4. TCP/IP and OSI model
es

Application

NFS

Presentation a 2 [lu

E lla lé

Application

RPL

Session

Transport layer (2protocols)—> TCP UDP | H

! Segment or:
! user diagrami

Network ICMP P (Supports 4 protocols) il Creates

H

layer ARP RARP i Datagram

Encapsulated

Data link layer

Protocols defined by the ¡Frame
underlying networks i

Physical layer

Bits

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5. NETWORK LAYER

ICMP (Internet control message protocol) -
handles error & controls messages

IGMP

ARP (Address resolution protocol) — obtaining the
physical address of a mode when the internet
address is known

RARP (Reverse address resolution protocol) —
allows a host to discover its internet address when
it knows only its physical address

6. Internet Protocol (IP) -1

Transmission mechanism used for TCP/IP
Unreliable & connectionless datagram
protocol

Assumes the unreliability of the underlying
layers & gives best to get a transmission
through to its destination

For good quality IP must be paired with a
reliable protocol like TCP

7. Internet Protocol (IP) — 2

» IP transports data in packets known as
datagrams

« IP functionality in a limited way is not a
weakness

« IP provides bare-bone transmission
functions ; frees the user to add only those
facilities necessary for a given application;
allows for maximum efficiency

8. IP Datagram

20-65536 bytes
20-60 bytes
(a) Datagram

|

Header Data

Ly VER | HLEN | Service type Total length of the

‘ - IP Datagram 16 bits
4 bits | 4 bits 8 bits (2 byte field)
Version Flags |Fragmentation

LENS Identification 16 bits 3 bits | Offset 13 bits

VER -

Time to live Protocol Header checksum
8 bits 8 bits 16 bits
Source IP address
Destination IP address
Option

Header length

(b) Header

vvzeNGKAR

9. IP datagram- 1

e Service type : defines how the datagram
should be handled; includes bits that define
the priority of the datagram; also contains
bits that specify type of service the sender
desires such as the level of throughput,
reliability and delay

¢ Total length : can define up to 65,536
bytes;two byte field.

10. IP datagram- 2

® Flags : Bits in the flags deal with fragmentation.
(Datagram can/cannot be fragmented; can be the first,
middle or last fragment etc.)

Fragmentation offset : A pointer shows the offset of the
data in the original datagram

Time to live : This field defines the number of hops a
datagram can travel before it is discarded; source host,
when it creates the datagram sets this field to an initial
value; when the datagram travels through the internet
router by router each router decrements this value by 1. If
this value becomes 0 before the datagram reaches its final
destination, the datagram is discarded. This prevents a
datagram from going back & forth between routers

11. Internet address - 1

¢ Protocol : field defines which upper layer protocol
data are encapsulated
Source address, destination address : Each field is
a four byte(32 bit) Internet address. It identifies
the original source & final destination of the
datagram respectively.
Options : The field gives more functionality to the
IP datagram. It carries field that control routing,
timing, management and alignment.

12. Internet address - 2

Addressing : Physical addresses are on NICs. It
identifies individual devices. The internet
requires an additional addressing constituent :

An address that identifies the connection of a
host to its network

Each internet consists of four bytes (32 bits)
defining three fields :

Class type
Netid
. Hostid

13. Internet address

each internet consists of four bytes (32 bits)
defining three fields :

Class type

Netid } varying lengths & depends on the

Hostid Class of the address

Class type E

14. Class A

Class B

Class C

Class D

Class E

Internet classes

byte 2

byte 3

byte 4

Hostid

Hostid

Hostid

Netid

Hostid

Netid

Hostid

Multicast address

Reserved for future use

Address

|

Lowest

15. Class range of internet addresses

Class A

Class B

Class C

Class D

Class E

From
Netid

Hostid

Netid

Lo) .
Hostid

0

.0.0.0

127

1299 «255.255

Netid

Hostid

128.0

0.0

Netid

192.0.0.

Hostid

Netid

Hostid

127

299.

255.255

Netid

Hostid

127

255

255.255

Hos

id

224.0.

0.0

.255:255.255

240 .0

.0.0

253.

255.255

16. Network & hosts addresses in an
internet

139.6.0.2 139.6.0.3
C, C

Network 1
139.6.0.0

139.6.0.4
178.5:2:3 171.26.05.08
R Gateway

Cio Gateway Ca Router]

178 .5.0.0))171.26.01. C, Cy

Network Network 2
E 171.26.01.05 171.26.01.06 [171.26.00.0
171.26.00.
Cy x
178.5.2.1 178.5.2.2 182:2:0.0

17. ARP request/response

Router

or host
ARP packet a \ \ \

questions about the

physical address of

anode. IP address it
gives

Host 1

Host 2

Host 3

One of the nodes
responds
identifying itself
as the right node
& gives the
physical address

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18. UDP Datagram Format

Le variable

k———8 bytes ——#

Header

Source port Destination port
address 16 bits Address 16 bits

Total length Clocksum
16 bits 16 bits

19. Delivers a
datagram

IP

Host-to-host protocol
Source host Destination host

20. NS
SD SS

Port-to-port addresses

PS

NV 3 x
EEE yw!

TCP or UDP

TCP or UDP

4

IP

IP

4

Data Link

Data Link

Physical

Physical

21. TCP segment

Header

(a) Datagram

|

Source port address

16 bits

Destination port address
16 bits

Sequence number

32 bits

HLEN —

Acknowledge number

32 bits

Header lengt

HLEN | Reserved | "| ® | ?

4 bits 16 bits

rlcls
glkln

: A E Window size

IM 16 bits

Control checksum

16 bits

Urgent pointer
16 bits

Options and

adding

22. Client/server Paradigm

Server
dient Server

Result

24. Using TELNET to login

User working
online

25. Steps involved in TELNET
(remote login) - 1

Ba Remote

Local host

Terminal
(Real)

TELNET
server

TELNET
Client

TCPNB

Standard Standard
code code

26. Steps involved in TELNET
(remote login) - 2

TELNET client transforms the output from the
actual terminal to standard code

TELNET server in the remote host receives the
information in the standard code

TELNET server will transform the information
into character accepted by remote host

The remote host is pooled into thinking that a
terminal is locally connected to it. (in other
words a virtual terminal is connected to the local
host)

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27. User
interface

Protocol
interpreter

FTP

Control connection

Protocol
interpreter

TCP/IP,

Data
transfer unit

Local host

Data connection

Data
Transfer
unit

Remote host

Remote

28. Local procedure call

C program
calling the
open
Function
is used here

C program
to access a
disk

Local
Disk

Local
host

User application

program

Local
procedure

29. Remote procedure call - 1

C program

Calling the
Open
Function

I]

Is used here

C program
to access a
dis

client]

S

RPC
Client

C program

Remote

host

Local
Disk

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30. 1.

Remote procedure call - 2

A program issues a call to the NFS client
process. NFS client formats the call for the
RPC client and passes it.

. RPC client transforms the data to a format

called XDR.(external data presentation) &
provides the interface with TCP/IP
transport mechanisms.

31. Remote procedure call - 3

3. At the remote host, RPC server retrieves the call
translates it out of XDR and passes it to the NFS
server.

4. NFS server relays the call to the remote disk.

5. The remote disk finally responds as if to a call &
opens the file to the NFS server. Similar process
is followed in the reverse order to work in the
opposite way.

32. Electronic Mail

(Sending & Receiving)

Spool Mail boxes Mail boxes Spool

NV) =,

Database Alias |, Database
Or disk aa or disk

Mail Ge ail transfer H DE qn =
agents Agents i MTA ATA)
(MTA) (MTA) : en —

Internet WELINGKAR

33. Router R;

Manager

um.

Router R,

Router

Router Ry

Router R;

Router R

Managed
(Agent)

Manager

TT

Routers R, to Ry are
Managed (Agent)

u

ua, Managed
(Agent)

34. World Wide Web

Web server B (Denmark)

Web server A (Mumbai)

_ lL .—

E
I TE

I >4

|

Web server C (Japan

a 1% Web server D (Chennai)

À

1 1

Î >
f

x

1 4

35. World wide web

“ Requires

A functional
architecture
A structural
architecture

A navigational
architecture

36. A Functional Architecture

<html>

<head>

<title> DATAMATION
Plugin </title>

</head>

<body>

<hp> newswire</hl>
<hl> DATAMATION
Magazine </hl>

<hl> Media kit </hl>

http://www.datamation.com

Proxy server

LAN HTML documents
interpreted by browsers

From
to the

internet

a

Fire wall

37. A structural architecture

DA
http://www.datamation.com

Newswire —
Live wire :
DATAMATION MANAGEMENT

Table of contents
Feature index

Cover story
Management
Desktops

Networks
[>> Software
E
Servers

38. Browser architecture

Many commercial browsers exist

These interpret and display a web
document. Each of these use the same
architecture

Browser has three parts :
Controller

Client programs
Interpreters

39. Browser architecture

controller

BROWSER

INTERPRETERS

[GOPHER]

40. Static documents

Fixed content documents are created and
stored in a server

Client accesses the document, a copy of the
document is received

User can use a browsing program to display
the document

User cannot change the contents;but the
contents can be changed in the server

41. Client

Static documents

Request for a

URL

Document

document

Response

42. Dynamic documents -1

These do not exist in predefined format
Documents are created by a web server
when a browser requests the document
When the request arrives, the web server
runs an application program to create the
dynamic document

Server then returns the output in response to
the browsers request for document

43. Dynamic documents - 2

Contents of document varies as these are
created for each request. Time and date are
types of dynamic information.

Client can request that the server run a
program in UNIX and send the result back

44. Dynamic documents

URL

Request for a

=

¡Document

document

=

Client

Response

Server

45. Dynamic documents
Steps

+ Client requests for
running a program.

« Running the program
creates document.

+ Respond

46. Active documents

Produce the
document D

D

P

Request for a
>
document
Copy of the program
Client Response Pl sent Server

Running the
program P1

47. Active documents
Steps

+ Client requests for a
copy of the program

Copy of the program

is sent by server.

Running the program
and creating the
document at the
client’s end.

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